02-08-2006, 09:16 PM
[left][color="#006600"]Sepioteuthis Lessoniana References[/color][/left]
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Akiyama, S., Kaihara, S., & Arimoto, T. (2004). Capture characteristics of a trammel net for oval squid sepioteuthis lessoniana in tateyama bay, chiba prefecture. Bulletin of the Japanese Society of Scientific Fisheries, 70(6) 865-871. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
In order to understand the capture characteristics of a trammel net for herded oval squid Sepioteuthis lessoniana, fishing method and catch composition were surveyed in Tateyama Bay, Chiba Prefecture, in 2002 and 2003. A trammel net with an inner mesh size of 85 mm an outer mesh size of 360 mm was used in the fishing operation. The trammel net was operation was divided into three stages: setting, herding and hauling. A total of 1,491 oval squid, 933 fish and 63 others were caught in 363 hauls. The discard rate based on the catch in number of the trammel net was estimated as 17 percent. The mean mantle length of oval squid was 28.0 plus or minus 5.8 cm. Oval squid smaller than 17 cm in mantle length were not captured by the trammel net. Oval squid were mostly taken in the central anc bottom part of the trammel net, and 95 percent of the oval squid were pocketed by the bag-shaped inner net.
Akiyama, S., Kaihara, S., Arimoto, T., & Toaki, T. (2004). Size selectivity of a trammel net for oval squid sepioteuthis lessoniana. Fisheries Science, 70(6) 945-951. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
The size selectivity of a trammel net for herded oval squid Sepioteuthis lessoniane in Tateyama Bay, Chiba Prefecture, was estimated by comparison between the mantle length frequency distributions of oval squid caught by a trammel net and by a set net. The measured mesh sizes of the inner net of the trammel net and of the final section of the set net were 85.3 and 11.3 mm, respectively. In the trammel net fishery where oval squid are herded into the net, most of the oval squid are caught in the bag-shaped inner net. Hence, the logistic function was employed for the size selectivity curve of the trammel net. The 'share each length's catch total' (SELECT) model was implemented for the estimation of the selectivity curve. The size selectivity r(l) of the trammel net for the oval squid was expressed as a logistic function of the mantle length l: r(l) = exp(-18.57 + 0.88 l)/[1 + exp(-18.57 + 0.88 l)]. From these logistic parameter estimates, the 50% selection mantle length and selection range (L sub(75)-L sub(25)) were calculated as 21.07 and 2.49 cm, respectively. The selection probability of oval squid whose mantle girth was equivalent to the mesh perimeter of the inner net was 0.09. Accordingly, oval squid of a girth smaller than the mesh perimeter were likely to pass through the mesh to escape from the net.
Chacko, D., Samuel, V. D., & Patterson, J. (2004). Effect of salinity and fly-ash on the embryonic development of the bigfin squid, sepioteuthis lessoniana. Journal of the Marine Biological Association of India, 46(2) 162-168. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Cephalopods breed in the near shore waters where the salinity fluctuations are more likely. Also, pollution from the adjoining industries is common in some of these areas. During the study, an attempt was made to find out the effect of salinity on the hatching of eggs of the bigfin squid, Sepioteuthis lessoniana. Embryonic development was found to be good at salinities 28ppt, 32ppt and 36ppt, while it was poor at 40ppt. No development was observed in 24ppt. Like wise, the effect of fly ash on the eggs of this species was tested at various concentrations in gram per liter of seawater. Mortality and premature hatching were observed at concentrations 25g, lOg, 5g, 1g, O.5g and O.lg. At 0.Olg concentration, the hatching was normal but the hatchlings died within two days.
Forsythe, J. W. (2002). Clinical variation in the growth rate versus temperature relationship of the reef squid, sepioteuthis lessoniana, from japan, okinawa and thailand. Bulletin of Marine Science, 71(2) 1120. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
The Pacific reef squid, Sepioteuthis lessoniana occurs over a broad geographic range in the Indo-Pacific. From the Red Sea in the east to Hawaii in the west and from North-Central Japan in the North to the Central coast of Australia in the south, this species is fished commercially in shallow coastal waters throughout its range. S. lessoniana is known to grow quickly reaching sizes of 1-2 kg in less than 1 yr and it is found in waters ranging in temperature from 16 degree C to 34 degree C. Over the past several years it has been possible to obtain field collected eggs of this species from the temperate/subtropical area of Tokyo Bay in Japan, the sub-tropical/tropical waters of Okinawa and the tropical waters of the Gulf of Thailand. Growth rate data were collected for each geographic group by culturing two groups of hatchlings concurrently at two different temperatures and comparing growth rates. These findings were then compared to other geographic groups. In growing these different groups through the life cycle, it became apparent that this species did not respond to temperature variation in a uniform manner when comparing results across this geographic cline. There was great consistency within groups with growth rate at a given temperature being very predictable. The slope of the relationship between growth rate and water temperature was almost identical between groups but the relative elevation of the relationship differed significantly. At a common seawater temperature S. lessoniana hatchlings from Japan grow faster than their congeners from Okinawa or Thailand. What does this tell us about how S. lessoniana adapts to different geographic environments and acute (El Nino/La Nina) temperature anomalies as well as possible responses to chronic (global warming) temperature change?.
Forsythe, J. W., Walsh, L. S., Turk, P. E., & Lee, P. G. (2001). Impact of temperature on juvenile growth and age at first egg-laying of the pacific reef squid sepioteuthis lessoniana reared in captivity. Mar.Biol, 138(1) 103-112. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Cephalopod mollusks exhibit highly plastic life cycle traits influenced primarily by the interactive effects of food availability, light cycle and temperature, with the latter perhaps the most influential. Hatchlings of the tropical reef squid Sepioteuthis lessoniana were hatched from field-collected eggs in the laboratory and cultured at different temperatures to evaluate the effect of temperature on growth rates. All groups showed rapid, sustained growth rates from hatching to a size of 10-25 g. Beyond this size range, growth was slower and not clearly exponential in form. Growth rate was closely linked to temperature. Squids grown at approximately 27 degree C attained a size of 10 g in as little as 45 days at sustained growth rates of 12.2% body weight /day (%bw/day), while squids cultured at 20 degree C required almost 100 days to attain the same size at rates of 5.7%bw/day. At an age of 55 days and approximately 1 g body weight, juvenile squids cultured at 20 degree C were able to accelerate growth rates from 5.7%bw/day to over 12%bw/day when temperature was raised to 27 degree C. They maintained this growth rate to a size of about 10 g and an age of at least 75 days post-hatching, indicating that body size and not age is the limiting factor for this rapid post-hatching growth. By comparison, conspecifics cultured near 27 degree C from hatching had shifted out of the rapid post-hatching growth phase by day 50 at sizes between 10 and 50 g. The hatchlings from temperate to subtropical Japan had consistently higher growth rates at comparable temperatures than hatchlings from tropical Okinawa. When plotted as growth rate versus temperature, the Japanese group had a clearly higher slope to the relationship than the tropical populations, equivalent to a 2%bw/day difference in growth rate at 25 degree C. Age at first egg-laying was decreased at higher culture temperatures; however, overall life span was not.
Furuya, H., Ota, M., Kimura, R., & Tsuneki, K. (2002). The kidneys of cephalopods: A unique habitat for dicyemids and chromidinids. Zoological Science, 19(12) 1423. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Fluid-filled renal and pancreatic coela, "kidneys", of cephalopods are unique habitats for the establishment and maintenance of parasites. The kidneys of 25 species of cephalopods were examined for parasite fauna and for histological comparison. Two phylogenetically distant organisms, dicyemid mesozoans and chromidinid ciliates, were found in 20 cephalopod species. Most benthic cephalopods were infected with dicyemids. Two pelagic species of cephalopods, Sepioteuthis lessoniana and Todarodes pacificus, also harbor dicyemids. Chromidinids were found only in decapods. Dicyemids and chromidinids occasionally occurred simultaneously in Euprymna morsei, Sepia kobiensis, Sepiella japonica, and T. pacificus. No parasites were found in the kidneys of small cephalopod species, Idiosepius paradoxus and Octopus parvus. Comparative histological study revealed that the external surface of kidneys varies morphologically in various cephalopod species. The rugged and convoluted external surface provides foothold for dicyemids and chromidinids. Thus the presence or absence of parasites is related to at least partly a degree of complexity in the external surface of kidneys.
Hayashi, S. (2003). Recent trend in oval squid, sepioteuthis lessoniana, fishery in toyama bay. Bulletin of Toyama Prefectural Fisheries Experiment Institute, (14) 11-28. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
The oval squid, Sepioteuthis lessoniana (Lesson, 1830), is one of the important species for fisheries in Toyama Prefecture. The landing of oval squid in Toyama Prefecture ranged from 17 tons/year (in 1996) to 439 (in 2000). Main fishing season for oval squid in Toyama Bay is in the autumn, during Septemper to December. Ratio of landings by set nets to the total landings is 99.2%, those by lift nets 0.5% and by trolling and gill-nets, 0.3%. There are two peaks of landings of oval squid in a year. The first peak occurs from May to June and the second from October to November. The first consists of adult squids and the second of juveniles reproduced from the first. The year landing is closely related to the mean water temperature during May to November. Mantle lengths of the squids for autumn in 1992 with high water temperature were larger than those landed in 1993 with low temperature.
Ikeda, Y., Ueta, Y., Sakurazawa, I., & Matsumoto, G. (2004). Transport of the oval squid sepioteuthis lessoniana ferussac, 1831 in lesson 1830-1831 (cephalopoda: Loliginidae) for up to 24 h and subsequent transfer to an aquarium. Fisheries Science, 70(1) 21-27. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Conditions for transporting live young and subadults of the squid Sepioteuthis lessoniana were investigated in a laboratory experiment and transport trial. In the lab experiment, survival was examined for various seawater conditions and transport procedures. The quality of the water containing the squid decreased (pH 4 degree C) after 24 h, but 12 of 33 examined squid (body weight (BW) 5.0-877 g) survived these changes. Squid survival was high when the BW : seawater volume ratio started below 30. Also, survival was higher in large containers such as a styrofoam box with large (>1620 cm super(2)) bottom area. Based on these criteria, 24 squid (BW 4 degree C) after 24 h, but 12 of 33 examined squid (body weight (BW) 5.0-877 g) survived these changes. Squid survival was high when the BW : seawater volume ratio started below 30. Also, survival was higher in large containers such as a styrofoam box with large (>1620 cm super(2)) bottom area. Based on these criteria, 24 squid (BW 2 h) acclimation period survived the transfer.
Jackson, G. D., & Moltschaniwskyj, N. A. (2002). Spatial and temporal variation in growth rates and maturity in the indo-pacific squid sepioteuthis lessoniana (cephalopoda: Loliginidae). Marine Biology, 140(4) 747-754. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Age, growth and maturity parameters are described for the Indo-Pacific squid Sepioteuthis lessoniana both temporally and spatially (equatorial, tropical and subtropical). Tropical squid that grew through periods of warming water temperatures grew 9% faster than squid that grew through periods of cool water temperatures. The tropical spring-hatched and equatorial squid had similar growth rates (3.24, 3.18 g/day) and these were significantly faster than the tropical summer/autumn hatched squid (2.89 g/day). The oldest squid aged was 224 days, but the majority of individuals were 400 g, 85% greater than tropical arid equatorial squid. Geographical differences revealed that subtropical mature winter females and males had mean ages > 150 days, respectively 17% and 23% older than their tropical mature winter counterparts. Temporal differences in age at maturity were also evident with tropical winter females and males having a mean age of ~6140 days, respectively 41% and 25% older than their summer counterparts. Cooler subtropical and winter tropical squid had the heaviest gonads ( > 15 g ovaries, > 1.5 g testes) compared to summer tropical and equatorial squid. However, relative gonad investment (GSI) values of the cooler squid were significantly lower with cool subtropical and winter tropical females having GSI values < 3 which was about half the value of the warmer water females. This study revealed considerable plasticity in the size-at-age of this species. The tropical population had growth parameters that fluctuated between an equatorial strategy (fast growth, small body size, and small gonads) and a subtropical strategy (large body size, slower growth, and large gonads) depending on season.
Jackson, G. D., & Moltschaniwskyj, N. A. (2001). The influence of ration level on growth and statolith increment width of the tropical squid sepioteuthis lessoniana (cephalopoda: Loliginidae): An experimental approach. Marine Biology, 138(4) 819-825. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Juvenile squids were grown in individual 2.6-1 floating enclosures and were fed either a high- or a low-ration diet of fish and the crustacean Acetes. Squids were maintained for a maximum of 44 days in two experiments. The high-ration individuals reached a significantly larger size in both experiments (27, 25.5 mm mean mantle length, ML) compared to their low-ration siblings (19 mm mean ML) in both experiments. The statolith increment widths prior to the start of the experiment were significantly wider (between 3 and 4 mu m) compared to the increment widths after the start of the experiment (between 2 and 3 mu m) both for the low- and the high-ration squids. High-ration squids also had significantly wider increments and larger statoliths than their low-ration siblings. Even though we detected consistent trends in daily statolith increment widths for the different feeding regimes, we could not detect variation in increment widths at a daily level of resolution (i.e. as a result of differences in day-to-day food intake at an individual level). This was probably due to the relatively consistent diet experienced by each individual. These experiments revealed that ration level influences squid growth rate, statolith size and daily statolith increment width.
Jaruwat Nabhitabhata, Panya Asawangkune, Sabaithip Amornjaruchit, Pichitra Promboon, Phuket Marine Biological Cent. (Thailand), & Suganthi Devadason Marine Research Inst. (SDMRI), Tuticorin (India). (2001). In Hylleberg J. (Ed.), Tolerance of eggs and hatchlings of neritic cephalopods to salinity changes. Retrieved August 2, 2006, from [url="http://www.csa.com/"]www.csa.com[/url]
Hatching of eggs of two species of neritic cephalopods, the bigfin squid (Sepioteuthis lessoniana) and pharaoh cuttlefish (Sepia pharaonis) differed significantly following brief immersion at eight levels of salinity, 12-44 ppt at 4 ppt intervals. More than 80% of eggs of both species hatched in 24, 28 and 32 ppt as did cuttlefish eggs at 36 ppt. Bigfin squid eggs failed to hatch in 12 and 40 ppt and eggs of cuttlefish failed to hatch in 16, 20, 40 and 44 ppt. Optimum salinity range for hatching was estimated at 21.8-36.6 ppt for bigfin squid and 22.5-37.5 ppt for cuttlefish. Outside the optimum range, the salinity tended to cause premature hatching, death of the embryos before organogenesis at high salinity, and abnormal development at low salinity. Survival of hatchlings of both species differed significantly after brief change to the eight levels of salinity in 24 hrs. The highest survival was in 28 and 32 ppt for bigfin squids (more than 70%) and in 24, 28, 32 and 36 ppt for cuttlefish (more than 80%). The range of optimum salinity for the survival was 23.2-35.5 ppt for bigfin squid and 21.4-39.4 ppt for pharaoh cuttlefish. Survival during gradual change of salinity was similar to that following sudden change. The benthic cuttlefish tolerated low salinity better than planktonic squid. Short-term immersion of hatchlings in salinities outside the optimum range, within the tolerable time, may be applied in control and treatment of diseases and parasites in aquaculture.
Koyama, J., Nanamori, N., & Segawa, S. (2000). Bioaccumulation of waterborne and dietary cadmium by oval squid, sepioteuthis lessoniana, and its distribution among organs. Marine pollution bulletin, 40(11) 961-967. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Bioaccumulation of cadmium (Cd) by oval squid, Sepioteuthis lessoniana, the relative contributions of Cd in water and food to bioaccumulation, and the distribution of cadmium among organs were studied. In a bioconcentration test, oval squid was exposed to 0.2 mg Cd/l seawater for 14 days, then was reared in Cd-free seawater for 14 days. After the exposure and elimination periods, the Cd concentrations in the whole body were 3.10 plus or minus 0.18 and 1.90 plus or minus 0.05 mu g/g wet weight (ww), respectively. The bioconcentration factor (BCF) was 15.5 after exposure for 14 days. The liver exhibited the highest Cd concentration (49.3 mu g/g ww), and had the highest proportion of organ Cd content (42.8%) to whole-body burden at the end of the exposure period. In a biomagnification test, oval squid was exposed to 0.12 mg Cd/l seawater for 15 days and was simultaneously fed mummichog, Fundulus heteroclitus, that were simultaneously exposed to the same Cd concentration. For a further eight days the squid was kept in Cd-free seawater and was fed mummichog that were also kept in Cd-free seawater. After the exposure and elimination periods, the Cd concentrations in the whole body were 4.18 plus or minus 0.69 and 2.80 plus or minus 0.44 mu g/g ww, respectively. The concentration of whole-body Cd in the oval squid that was derived from water was estimated at 1.86 mu g/g ww after calculation of a BCF from the bioconcentration test. The contribution of Cd derived from water to the whole-body Cd burden appeared similar to that of the Cd derived from food. In the biomagnification test, the liver Cd concentration (58.8 mu g/g ww) and its proportion of the whole-body Cd concentration (40.6%) were the highest among those of all the organs after exposure for 15 days, regardless of the uptake route. Because wild squid seem to be exposed to much lower Cd concentrations in water and are subjected to similar Cd concentrations in their prey, compared with squid of the present study, the main Cd source for squid would appear to be dietary.
Mhitu, H., Mgaya, Y., Ngoile, M., Western Indian Ocean Marine Science Association, Zanzibar (Tanzania), & Institute of Marine Sciences, Zanzibar (Tanzania) University of Dar es Salaam. (2001). In Richmond M. D., Francis J.(Eds.), Growth and reproduction of the big fin squid, sepioteuthis lessoniana, in the coastal waters of zanzibar. Zanzibar (Tanzania): IMS/WIOMSA. Retrieved August 2, 2006, from [url="http://www.csa.com/"]www.csa.com[/url]
Aspects of growth and reproduction of the bigfin reef squid Sepioteuthis lessoniana (Lesson, 1830) in the coastal waters of Zanzibar were investigated with a view to obtaining basic information that could be used in the management of the squid fishery in the area. A total of 664 specimens, comprising 344 females and 320 males, were collected between April 1994 and March 1995. The size of individuals ranged from 63 mm to 347 mm and 72 mm to 277 mm dorsal mantle length (DML) for males and females respectively. Growth was not significantly different (p > 0.001) between males and females as revealed by length (L)-weight (W) relationship, thus the following expression was used to describe the growth of S. lessoniana; W = 0.0005 L super(2.255). Both males and females exhibited allometric growth. Gonad maturation, as revealed by maturity stages and indices, peaked in July, indicating that spawning period begins around July. Size at maturity was determined by statistical and graphical methods. Size (DML plus or minus 95 CL) at maturity as determined by the statistical method was 138.9 plus or minus 6.4 mm and 162 plus or minus 4.3 mm for males and females respectively, while the graphical method yielded 149.5 mm for males and 162.8 mm for females. Fecundity for female individuals ranged from 180 to 1180 eggs with a mean of 680 eggs for individuals of size range 140-249 mm DML.
Pecl, G. (2001). Flexible reproductive strategies in tropical and temperate sepioteuthis squids. Mar.Biol, 138(1) 93-101. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
A major difficulty confronting the determination of cephalopod reproductive life history is assessing over what portion of the life span an individual is reproductively mature and actively depositing eggs. This paper assesses the potential of the tropical Sepioteuthis lessoniana and two genetic types of the temperate Sepioteuthis australis, to spawn multiple batches of eggs at discrete times throughout the adult life span. This is achieved by histological examination of the ovarian gametogenic cycle and detailed morphological assessments of the reproductive system, in conjunction with other biological information. The genetic type of S. australis found at the northern limits of its Australian distribution showed evidence of a high correlation between body size and quantity of mature eggs, suggesting that eggs may be accumulating to be laid in a single batch. Although maturation was also a sizerelated process in S. lessoniana and Tasmanian S. australis, oviduct size was not correlated with body weight in mature females, which is indicative of multiple spawning. Further supporting evidence includes relatively low gonadosomatic indices, the heavier weight of the ovary relative to the oviduct, and the feeding activity of mature animals. Mature S. lessoniana and S. australis individuals were present at each location over very wide age and size ranges. In Tasmanian waters, there were distinct seasonal differences in the reproductive biology of S. australis. Summer-caught individuals had much higher gonadosomatic indices and may have been laying larger batches of eggs compared with winter-caught individuals. Summer-caught females also showed a negative correlation between egg size and egg number within the oviduct, suggesting that some individuals were producing fewer, larger eggs and others many smaller eggs. Evidence suggests that considerable flexibility is inherent in the reproductive strategy of both S. lessoniana and S. australis.
Pratoomchat, B., Natsukari, Y., Miki, I., & Chalermwat, K. (2001). Allozyme determination of genetic diversity in japanese and thai populations of oval squid (sepioteuthis lessoniana lesson, 1830). Umi/la mer, 39(3) 133-139. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Genetic variation and genotypic population structure of two geographic populations of oval squid (Sepioteuthis lessoniana Lesson, 1830), captured from Nagasaki (Japan) and Rayong (Thailand) were investigated using multi-locus allozyme analysis. On the basis of 22 loci screened, the percentage of polymorphic loci and observed heterozygosity were 45.45% and 0.28 for Japanese and 50.00% and 0.23 for Thai populations, respectively. These results suggest relatively high genetic distances between these population were observed (D=0.003). A lack of genetic differentiation between the Japanese and Thai populations of S. lessoniana suggests a panmictic gene pool of S. lessoniana over a wide geographic area.
Samuel, V. D., & Patterson, J. (2002). Intercapsular embryonic development of the big fin squid sepioteuthis lessoniana (loliginidae). Indian Journal of Marine Sciences, 31(2) 150-152. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
The egg masses of big fin squid, Sepioteuthis lessoniana were collected from the wild and their intercapsular embryonic development was studied. The average incubation period of the egg varied between 18-20 days. The cleavage started on the first day and the mantle developed between third and fifth day. The yolk started decreasing eighth day onwards. The tentacles with the sucker primordia on the tip were prominent from tenth day. The yolk totally reduced between thirteenth and seventeenth day and the paralarvae hatched out on eighteenth day. The developmental stages of the embryo inside the capsules during the incubation period is understood.
Semmens, J. M. (2002). Changes in the digestive gland of the loliginid squid sepioteuthis lessoniana (lesson 1830) associated with feeding. Journal of experimental marine biology and ecology, 274(1) 19-39. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Changes associated with feeding in the histological and cytological structure of the digestive gland of the loliginid squid Sepioteuthis lessoniana were examined, along with the nature of both the intracellular and extracellular enzymes produced by the gland. The timing of the release of the extracellular enzymes during the digestive cycle was also determined using a quantitative experimental program. Like that of all coleoid cephalopods, the digestive gland was characterised by one type of cell with several functional stages. As is the case for other loliginid squids, however, the digestive cells did not contain the large enzyme-carrying boules that characterise the digestive glands of most cephalopods. Instead, smaller secretory granules were found in the digestive cells and these may be the enzyme carriers. The prominent rough endoplasmic reticulum, large mitochondria and active Golgi complexes present in the digestive cells are characteristic of cephalopods and indicate a high metabolic activity. Like that of other cephalopods, endocytotic absorption of nutrients and intracellular digestion occurs in the digestive gland of this squid. From quantitative and qualitative examinations of structural changes in the digestive gland of S. lessoniana after feeding, a schedule of its function during the course of digestion was proposed. This indicated that digestion was very rapid, being completed in as little as 4 h in S. lessoniana. Extracellular digestive enzymes were only released after the first hour following feeding, which implies that they are stored in the stomach between meals to increase digestive efficiency.
Sharifuddin Bin Andy Omar, Danakusumah, E., Rani, C., Siswanto, E., Hade, A., & Phuket Marine Biological Cent. (Thailand) et al. (2001). In Hylleberg J. (Ed.), Incubation period and hatching rate of bigfin squid, sepioteuthis lessoniana, in 24 to 38 ppt salinity. Retrieved August 2, 2006, from [url="http://www.csa.com/"]www.csa.com[/url]
Together with Sepiella inermis and Loligo spp., the bigfin squid Sepioteuthis lessoniana (Lesson, 1830) is one of the important species, which have high value in Indonesia. In the present study, the effect of salinity on the incubation period and hatching rate of S. lessoniana was done at the Bojonegara Research Station for Coastal Aquaculture, Indonesia in 2000. Squid eggs were collected from Banten Bay waters. Eight salinities from 24-38 ppt were tested at 2 ppt intervals. 40 ppt salinity was lethal. The highest hatching rate (97%) was found in 32 ppt and the lowest (20%) in 38 ppt. The mantle length of the larvae ranged from 5.29 to 5.91 mm and the weight from 0.028 to 0.031 g.
Shuichi Shigeno, Kotaro Tsuchiya, & Susumu Segawa. (2001). Conserved topological patterns and heterochronies in loliginid cephalopods: Comparative developmental morphology of the oval squid sepioteuthis lessoniana. Invertebrate reproduction and development, 39(3) 161-174. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Development of the oval squid Sepioteuthis lessoniana is marked by a large embryonic size resulting in the most fully developed planktonic hatchlings within loliginids. We analyzed the embryonic development with special reference to the external morphology and the surface ultrastructure with a scanning electron microscope to identify both phylogenetic conservation and diversity of structures in the organogenesis of a loliginid. Developmental states of various cilia, namely the scattered, tuft, and uniform types are described. The ciliature pattern of S. lessoniana is more closely similar to the patterns of other loliginids than to those of sepioids and sepiolids, although characteristic numerous uniform-type cilia exist in the embryos of S. lessoniana. The conserved pattern can be recognized in the oganogenesis of S. lessoniana and other loliginids; on the other hand, heterochronic variations are noted, particularly in photosensitive organs and chromatophores. Eye pigmentation does not start at the same stage as in other loliginids and it is unlikely that the heterochronic variation of eye pigmentation is correlated to embryonic size. Chromatophores of S. lessoniana appeared earlier than those of other loliginids. Although hatchlings of S. lessoniana have a more strongly developed arm crown than other loliginids, the suckers arise at similar stages. These ontogenetic variations in loliginids may be considered together with the early mode of life.
Thompson, J. T., & Kier, W. M. (2002). Ontogeny of squid mantle function: Changes in the mechanics of escape-jet locomotion in the oval squid, sepioteuthis lessoniana lesson, 1830. Biological Bulletin, Marine Biological Laboratory, Woods Hole, 203(1) 14-26. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
In Sepioteuthis lessoniana, the oval squid, ontogenetic changes in the kinematics of the mantle during escape-jet locomotion imply a decline in the relative mass flux of the escape jet and may affect the peak weight-specific thrust of the escape jet. To examine the relationship between ontogenetic changes in the kinematics of the mantle and the thrust generated during the escape jet, we simultaneously measured the peak thrust and the kinematics of the mantle of squid tethered to a force transducer. We tested an ontogenetic series of S. lessoniana that ranged in size from 5 to 40 mm dorsal mantle length (DML). In newly hatched squids, thrust peaked 40 ms after the start of the escape jet and reached a maximum of between 0.10 mN and 0.80 mN. In the largest animals, thrust peaked 70 ms after the start of the escape jet and reached a maximum of between 18 mN and 110 mN. Peak thrust was normalized by the wet weight of the squid and also by the cross-sectional area of the circumferential muscle that provides power for the escape jet. The weight-specific peak thrust of the escape jet averaged 0.36 in newly hatched squid and increased significantly to an average of 1.5 in the largest squids measured (P < 0.01). The thrust per unit area of circumferential muscle averaged 0.25 mN/mm super(2) in hatchlings and increased significantly to an average of 1.4 mN /mm super(2) in the largest animals tested (P < 0.01). The impulse of the escape jet was also lowest in newly hatched individuals (1.3 mN times s) and increased significantly to 1000 mN times s in the largest squids measured (P < 0.01). These ontogenetic changes in the mechanics of the escape jet suggest (1) that propulsion efficiency of the exhalant phase of the jet is highest in hatchlings, and (2) that the mechanics of the circumferential muscles of the mantle change during growth.
Thompson, J. T., & Kier, W. M. (2001). Ontogenetic changes in fibrous connective tissue organization in the oval squid, sepioteuthis lessoniana lesson, 1830. Biological Bulletin, Marine Biological Laboratory, Woods Hole, 201(2) 136-153. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Ontogenetic changes in the organization and volume fraction of collagenous connective tissues were examined in the mantle of Sepioteuthis lessoniana, the oval squid. Outer tunic fiber angle (the angle of a tunic collagen fiber relative to the long axis of the squid) decreased from 33.5 degree in newly hatched animals to 17.7 degree in the largest animals studied. The arrangement of intramuscular collagen fiber systems 1 (IM-1) and 2 (IM-2) also changed significantly during ontogeny. Because of the oblique trajectory of the IM-1 collagen fibers, two fiber angles were needed to describe their organization: (1) IM-1 sub(SAG), the angle of an IM-1 collagen fiber relative to the squid's long axis when viewed from a sagittal plane and (2) IM-1 sub(TAN), the angle of an IM-1 collagen fiber relative to the squid's long axis when viewed from a plane tangential to the outer curvature of the mantle. The sagittal component (IM-1 sub(SAG)) of the IM-1 collagen fiber angle was lowest in hatchling squid (32.7 degree ) and increased exponentially during growth to 43 degree in squid with a dorsal mantle length (DML) of 15 mm. In squid larger than 15 mm DML, IM-1 sub(SAG) fiber angle did not change. The tangential component (IM-1 sub(TAN)) of IM-1 collagen fiber angle was highest in hatchling squid (39 degree ) and decreased to 32 degree in the largest squid examined. IM-2 collagen fiber angle (the angle of an IM-2 collagen fiber relative to the outer surface of the mantle) was lowest in hatchling squid (34.6 degree ) and increased exponentially to about 50 degree in 15-mm DML animals. In squid larger than 15 mm DML, IM-2 fiber angle increased slightly with size. The volume fraction of collagen in IM-1 and IM-2 increased 68 and 36 times, respectively, during growth. The ontogenetic changes in the organization of collagen fibers in the outer tunic, IM-1, and IM-2 may lead to ontogenetic differences in the kinematics of mantle movement and in elastic energy storage during jet locomotion.
Thompson, J. T., & Kier, W. M. (2001). Ontogenetic changes in mantle kinematics during escape-jet locomotion in the oval squid, sepioteuthis lessoniana lesson, 1830. Biological Bulletin, Marine Biological Laboratory, Woods Hole, 201(2) 154-166. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
We investigated the kinematics of mantle movement during escape jet behavior in an ontogenetic series of Sepioteuthis lessoniana, the oval squid. Changes in mantle diameter during the jet were measured from digitized S-VHS video fields of tethered animals that ranged in age from hatchlings to 9 weeks. The amplitude of both mantle contraction and mantle hyperinflation (expressed as percent change from the resting mantle diameter) during an escape jet was significantly greater in hatchlings than in older, larger squid (P < 0.05). The maximum amplitude of mantle contraction during the escape jet decreased from an average of -40% in hatchlings to -30% in the largest animals studied. The maximum amplitude of mantle hyperinflation decreased from an average of 18% in hatchlings to 9% in the largest squid examined. In addition, the maximum rate of mantle contraction decreased significantly during ontogeny (P < 0.05), from a maximum of 8.6 mantle circumference lengths per second (L/s) in hatchlings to 3.8 L/s in the largest animals studied. The ontogenetic changes in the mantle kinematics of the escape jet occurred concomitantly with changes in the organization of collagenous connective tissue fiber networks in the mantle. The alteration in mantle kinematics during growth may result in proportionately greater mass flux during the escape jet in newly hatched squid than in larger animals.
Thompson, J. T., & Kier, W. M. (2006). Ontogeny of mantle musculature and implications for jet locomotion in oval squid sepioteuthis lessoniana. Journal of Experimental Biology, 209(3) 433-443. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
We examined the relationship between mantle muscle structure and mantle kinematics in an ontogenetic series (5-85 mm dorsal mantle length) of oval squid, Sepioteuthis lessoniana. Thick filament length increased during growth in the mantle muscle fibres that power jet locomotion (i.e. the circular muscles). The thick filament length of both the superficial mitochondria-rich (SMR; analogous to vertebrate red muscle fibres) and central mitochondria-poor (CMP; analogous to vertebrate white muscle fibres) circular muscles increased significantly during ontogeny. Thick filaments in the SMR circular muscle fibres of newly hatched squid (N=5) ranged from 0.7 to 1.4 mu m and averaged 1.0 mu m, while the thick filaments of the SMR fibres of the largest squids (N=4) studied ranged from 1.2 to 3.4 mu m and averaged 1.9 mu m. The ontogeny of thick filament length in the CMP circular muscle fibres showed a similar trend. The range for hatchling CMP circular muscles was 0.7-1.4 mu m, with an average of 1.0 mu m, whereas the range and average for the largest squids studied were 0.9-2.2 mu m and 1.5 mu m, respectively. Within an individual hatchling, we noted no significant differences between the thick filament lengths of the SMR and CMP fibres. Within an individual juvenile, the thick filaments of the SMR fibres were similar to 25% longer than the CMP fibres. The change in thick filament length may alter the contractile properties of the circular muscles and may also result in a decrease in the rate of mantle contraction during jetting. In escape-jet locomotion, the maximum rate of mantle contraction was highest in newly hatched squid and declined during ontogeny. The maximum rate of mantle contraction varied from 7-13 muscle lengths per second in newly hatched squid (N=14) and from 3-5 muscle lengths per second in the largest squids (N=35) studied.
Tokai, T., & Ueta, Y. (2002). Size selectivity of squid jig for oval squid sepioteuthis lessoniana, and its relationship to prey-size selectivity. Bulletin of Marine Science, 71(2) 1141-1142. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Squid jigging and small sized set net fisheries catch the oval squid Sepioteuthis lessoniana in the coastal waters along the Pacific Ocean coast of Tokushima Prefecture, Japan. Most squid jigs used there are ready-made, colored, and prawn-shaped lures with a double ring of barbless hooks, and their body lengths (length of shrimp-shaped part of the jig, apart from the hooks) are about 12 cm. In this study, the set nets were regarded as a non-selective fishing gear due to the small enough mesh of the net, and their catch as a representative of the size frequency of the squid population in the fishing area. Size selectivity curve of squid-jig fisheries was estimated with the extended SELECT (Share Each LEngth's Catch Total) analysis model by comparing the size distributions of catches by squid-jigs and by set-nets carried out simultaneously in the same fishing area. As a result, size-selectivity r(l) in the squid jig size was expressed as a logistic function of mantle length l, r(l) = exp (-10.0 + 0.485 l) / [1 + exp(-10.0 + 0.485 l)]. From these logistic-parameter estimates, retention probability of the oval squid of 12cm mantle length was calculated to be 1.5 %. This implies that oval squid of smaller size than the jig of 12cm body length were not caught by the squid jig. In general, before squid seizes prey with its tentacles and arms the squid judges with their high visual acuity whether the prey size is appropriate or not. In rearing experiments, oval squid were most likely to attack a prey smaller than their body size, and when the squid seized a little larger prey they often discarded parts of the prey. In contrast, oval squid of a small size were often preyed on by rudder-fish Girella punctata of a size larger than the squid. Thus, oval squid appeared to feed on prey of a size smaller or a size relative to their own body size and may be unable, or select not, to attack prey larger than their own body size. These mean that oval squid have prey-size selectivity. For squid jigging to succeed, the squid must attack the jig as it would a prey; therefore a likely explanation of the squid jig size-selectivity found here is that it is a type of prey-size selectivity by the oval squid.
Triantafillos, L., & Adams, M. (2005). Genetic evidence that the northern calamary, sepioteuthis lessoniana, is a species complex in australian waters. ICES Journal of Marine Science, 62(8) 1665-1670. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Allozyme electrophoresis was used to investigate the taxonomic status of northern calamary Sepioteuthis lessoniana (Lesson 1830) from two sites in Shark Bay, Western Australia. Of the 40 squid examined at 38 presumptive loci, four individuals from the oceanic site were clearly differentiated from the rest by fixed allelic differences at four loci (Acp, Got2, Idh2, and PepD) and near-fixed differences at another three (Est, Ocdh, and 6Pgd). The genetic distances between these two groups of individuals (13% Fixed Differences and Nei, D (1978)=0.178) were roughly twofold greater than those between the two cryptic taxa in the southern calamary S. australis, but are considerably smaller than those between the northern and southern calamary. The most likely explanation for these data is that S. lessoniana comprises two ''cryptic'' biological species in this region. Further studies are needed to delineate the total number of species found throughout Australasia for this important loliginid squid.
Walsh, L. S., Turk, P. E., & Lee, P. G. (2002). Mariculture of the loliginid squid sepioteuthis lessoniana through seven successive generations. Aquaculture, 212(1-4) 245-262. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Sepioteuthis lessoniana is a commercially important squid throughout the Indo-West Pacific and is a useful species in biomedical research. It has now been cultured through seven successive generations in closed, recirculating seawater systems. Egg viability was highest in the parental generation (34.9%) and significantly decreased in the next six generations with a viability rate of 1.56-13%. The highest hatchling survival was in G4 (80.3%) and the lowest was in G3 (26.3%). Water quality was maintained at acceptable levels during each successive generation (NH40.1 ppm, NO20.05 ppm, NO350 ppm, pH>8.0). Life spans ranged from 169 to 262 days (5.6-8.7 months) with a mean of 208 days (6.9 months). The seven generations reached mean adult sizes at 500-900 g. The age of sexual maturity for females was recorded for all populations except G6 and ranged from 146 to 224 days (4.9-7.5 months) with an average of 171 days (5.7 months). Sex ratios did not consistently vary from 1:1 in any generation. Live food (i.e., crustaceans and fish) was the only food supplied throughout their life cycle.
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Akiyama, S., Kaihara, S., & Arimoto, T. (2004). Capture characteristics of a trammel net for oval squid sepioteuthis lessoniana in tateyama bay, chiba prefecture. Bulletin of the Japanese Society of Scientific Fisheries, 70(6) 865-871. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
In order to understand the capture characteristics of a trammel net for herded oval squid Sepioteuthis lessoniana, fishing method and catch composition were surveyed in Tateyama Bay, Chiba Prefecture, in 2002 and 2003. A trammel net with an inner mesh size of 85 mm an outer mesh size of 360 mm was used in the fishing operation. The trammel net was operation was divided into three stages: setting, herding and hauling. A total of 1,491 oval squid, 933 fish and 63 others were caught in 363 hauls. The discard rate based on the catch in number of the trammel net was estimated as 17 percent. The mean mantle length of oval squid was 28.0 plus or minus 5.8 cm. Oval squid smaller than 17 cm in mantle length were not captured by the trammel net. Oval squid were mostly taken in the central anc bottom part of the trammel net, and 95 percent of the oval squid were pocketed by the bag-shaped inner net.
Akiyama, S., Kaihara, S., Arimoto, T., & Toaki, T. (2004). Size selectivity of a trammel net for oval squid sepioteuthis lessoniana. Fisheries Science, 70(6) 945-951. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
The size selectivity of a trammel net for herded oval squid Sepioteuthis lessoniane in Tateyama Bay, Chiba Prefecture, was estimated by comparison between the mantle length frequency distributions of oval squid caught by a trammel net and by a set net. The measured mesh sizes of the inner net of the trammel net and of the final section of the set net were 85.3 and 11.3 mm, respectively. In the trammel net fishery where oval squid are herded into the net, most of the oval squid are caught in the bag-shaped inner net. Hence, the logistic function was employed for the size selectivity curve of the trammel net. The 'share each length's catch total' (SELECT) model was implemented for the estimation of the selectivity curve. The size selectivity r(l) of the trammel net for the oval squid was expressed as a logistic function of the mantle length l: r(l) = exp(-18.57 + 0.88 l)/[1 + exp(-18.57 + 0.88 l)]. From these logistic parameter estimates, the 50% selection mantle length and selection range (L sub(75)-L sub(25)) were calculated as 21.07 and 2.49 cm, respectively. The selection probability of oval squid whose mantle girth was equivalent to the mesh perimeter of the inner net was 0.09. Accordingly, oval squid of a girth smaller than the mesh perimeter were likely to pass through the mesh to escape from the net.
Chacko, D., Samuel, V. D., & Patterson, J. (2004). Effect of salinity and fly-ash on the embryonic development of the bigfin squid, sepioteuthis lessoniana. Journal of the Marine Biological Association of India, 46(2) 162-168. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Cephalopods breed in the near shore waters where the salinity fluctuations are more likely. Also, pollution from the adjoining industries is common in some of these areas. During the study, an attempt was made to find out the effect of salinity on the hatching of eggs of the bigfin squid, Sepioteuthis lessoniana. Embryonic development was found to be good at salinities 28ppt, 32ppt and 36ppt, while it was poor at 40ppt. No development was observed in 24ppt. Like wise, the effect of fly ash on the eggs of this species was tested at various concentrations in gram per liter of seawater. Mortality and premature hatching were observed at concentrations 25g, lOg, 5g, 1g, O.5g and O.lg. At 0.Olg concentration, the hatching was normal but the hatchlings died within two days.
Forsythe, J. W. (2002). Clinical variation in the growth rate versus temperature relationship of the reef squid, sepioteuthis lessoniana, from japan, okinawa and thailand. Bulletin of Marine Science, 71(2) 1120. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
The Pacific reef squid, Sepioteuthis lessoniana occurs over a broad geographic range in the Indo-Pacific. From the Red Sea in the east to Hawaii in the west and from North-Central Japan in the North to the Central coast of Australia in the south, this species is fished commercially in shallow coastal waters throughout its range. S. lessoniana is known to grow quickly reaching sizes of 1-2 kg in less than 1 yr and it is found in waters ranging in temperature from 16 degree C to 34 degree C. Over the past several years it has been possible to obtain field collected eggs of this species from the temperate/subtropical area of Tokyo Bay in Japan, the sub-tropical/tropical waters of Okinawa and the tropical waters of the Gulf of Thailand. Growth rate data were collected for each geographic group by culturing two groups of hatchlings concurrently at two different temperatures and comparing growth rates. These findings were then compared to other geographic groups. In growing these different groups through the life cycle, it became apparent that this species did not respond to temperature variation in a uniform manner when comparing results across this geographic cline. There was great consistency within groups with growth rate at a given temperature being very predictable. The slope of the relationship between growth rate and water temperature was almost identical between groups but the relative elevation of the relationship differed significantly. At a common seawater temperature S. lessoniana hatchlings from Japan grow faster than their congeners from Okinawa or Thailand. What does this tell us about how S. lessoniana adapts to different geographic environments and acute (El Nino/La Nina) temperature anomalies as well as possible responses to chronic (global warming) temperature change?.
Forsythe, J. W., Walsh, L. S., Turk, P. E., & Lee, P. G. (2001). Impact of temperature on juvenile growth and age at first egg-laying of the pacific reef squid sepioteuthis lessoniana reared in captivity. Mar.Biol, 138(1) 103-112. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Cephalopod mollusks exhibit highly plastic life cycle traits influenced primarily by the interactive effects of food availability, light cycle and temperature, with the latter perhaps the most influential. Hatchlings of the tropical reef squid Sepioteuthis lessoniana were hatched from field-collected eggs in the laboratory and cultured at different temperatures to evaluate the effect of temperature on growth rates. All groups showed rapid, sustained growth rates from hatching to a size of 10-25 g. Beyond this size range, growth was slower and not clearly exponential in form. Growth rate was closely linked to temperature. Squids grown at approximately 27 degree C attained a size of 10 g in as little as 45 days at sustained growth rates of 12.2% body weight /day (%bw/day), while squids cultured at 20 degree C required almost 100 days to attain the same size at rates of 5.7%bw/day. At an age of 55 days and approximately 1 g body weight, juvenile squids cultured at 20 degree C were able to accelerate growth rates from 5.7%bw/day to over 12%bw/day when temperature was raised to 27 degree C. They maintained this growth rate to a size of about 10 g and an age of at least 75 days post-hatching, indicating that body size and not age is the limiting factor for this rapid post-hatching growth. By comparison, conspecifics cultured near 27 degree C from hatching had shifted out of the rapid post-hatching growth phase by day 50 at sizes between 10 and 50 g. The hatchlings from temperate to subtropical Japan had consistently higher growth rates at comparable temperatures than hatchlings from tropical Okinawa. When plotted as growth rate versus temperature, the Japanese group had a clearly higher slope to the relationship than the tropical populations, equivalent to a 2%bw/day difference in growth rate at 25 degree C. Age at first egg-laying was decreased at higher culture temperatures; however, overall life span was not.
Furuya, H., Ota, M., Kimura, R., & Tsuneki, K. (2002). The kidneys of cephalopods: A unique habitat for dicyemids and chromidinids. Zoological Science, 19(12) 1423. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Fluid-filled renal and pancreatic coela, "kidneys", of cephalopods are unique habitats for the establishment and maintenance of parasites. The kidneys of 25 species of cephalopods were examined for parasite fauna and for histological comparison. Two phylogenetically distant organisms, dicyemid mesozoans and chromidinid ciliates, were found in 20 cephalopod species. Most benthic cephalopods were infected with dicyemids. Two pelagic species of cephalopods, Sepioteuthis lessoniana and Todarodes pacificus, also harbor dicyemids. Chromidinids were found only in decapods. Dicyemids and chromidinids occasionally occurred simultaneously in Euprymna morsei, Sepia kobiensis, Sepiella japonica, and T. pacificus. No parasites were found in the kidneys of small cephalopod species, Idiosepius paradoxus and Octopus parvus. Comparative histological study revealed that the external surface of kidneys varies morphologically in various cephalopod species. The rugged and convoluted external surface provides foothold for dicyemids and chromidinids. Thus the presence or absence of parasites is related to at least partly a degree of complexity in the external surface of kidneys.
Hayashi, S. (2003). Recent trend in oval squid, sepioteuthis lessoniana, fishery in toyama bay. Bulletin of Toyama Prefectural Fisheries Experiment Institute, (14) 11-28. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
The oval squid, Sepioteuthis lessoniana (Lesson, 1830), is one of the important species for fisheries in Toyama Prefecture. The landing of oval squid in Toyama Prefecture ranged from 17 tons/year (in 1996) to 439 (in 2000). Main fishing season for oval squid in Toyama Bay is in the autumn, during Septemper to December. Ratio of landings by set nets to the total landings is 99.2%, those by lift nets 0.5% and by trolling and gill-nets, 0.3%. There are two peaks of landings of oval squid in a year. The first peak occurs from May to June and the second from October to November. The first consists of adult squids and the second of juveniles reproduced from the first. The year landing is closely related to the mean water temperature during May to November. Mantle lengths of the squids for autumn in 1992 with high water temperature were larger than those landed in 1993 with low temperature.
Ikeda, Y., Ueta, Y., Sakurazawa, I., & Matsumoto, G. (2004). Transport of the oval squid sepioteuthis lessoniana ferussac, 1831 in lesson 1830-1831 (cephalopoda: Loliginidae) for up to 24 h and subsequent transfer to an aquarium. Fisheries Science, 70(1) 21-27. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Conditions for transporting live young and subadults of the squid Sepioteuthis lessoniana were investigated in a laboratory experiment and transport trial. In the lab experiment, survival was examined for various seawater conditions and transport procedures. The quality of the water containing the squid decreased (pH 4 degree C) after 24 h, but 12 of 33 examined squid (body weight (BW) 5.0-877 g) survived these changes. Squid survival was high when the BW : seawater volume ratio started below 30. Also, survival was higher in large containers such as a styrofoam box with large (>1620 cm super(2)) bottom area. Based on these criteria, 24 squid (BW 4 degree C) after 24 h, but 12 of 33 examined squid (body weight (BW) 5.0-877 g) survived these changes. Squid survival was high when the BW : seawater volume ratio started below 30. Also, survival was higher in large containers such as a styrofoam box with large (>1620 cm super(2)) bottom area. Based on these criteria, 24 squid (BW 2 h) acclimation period survived the transfer.
Jackson, G. D., & Moltschaniwskyj, N. A. (2002). Spatial and temporal variation in growth rates and maturity in the indo-pacific squid sepioteuthis lessoniana (cephalopoda: Loliginidae). Marine Biology, 140(4) 747-754. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Age, growth and maturity parameters are described for the Indo-Pacific squid Sepioteuthis lessoniana both temporally and spatially (equatorial, tropical and subtropical). Tropical squid that grew through periods of warming water temperatures grew 9% faster than squid that grew through periods of cool water temperatures. The tropical spring-hatched and equatorial squid had similar growth rates (3.24, 3.18 g/day) and these were significantly faster than the tropical summer/autumn hatched squid (2.89 g/day). The oldest squid aged was 224 days, but the majority of individuals were 400 g, 85% greater than tropical arid equatorial squid. Geographical differences revealed that subtropical mature winter females and males had mean ages > 150 days, respectively 17% and 23% older than their tropical mature winter counterparts. Temporal differences in age at maturity were also evident with tropical winter females and males having a mean age of ~6140 days, respectively 41% and 25% older than their summer counterparts. Cooler subtropical and winter tropical squid had the heaviest gonads ( > 15 g ovaries, > 1.5 g testes) compared to summer tropical and equatorial squid. However, relative gonad investment (GSI) values of the cooler squid were significantly lower with cool subtropical and winter tropical females having GSI values < 3 which was about half the value of the warmer water females. This study revealed considerable plasticity in the size-at-age of this species. The tropical population had growth parameters that fluctuated between an equatorial strategy (fast growth, small body size, and small gonads) and a subtropical strategy (large body size, slower growth, and large gonads) depending on season.
Jackson, G. D., & Moltschaniwskyj, N. A. (2001). The influence of ration level on growth and statolith increment width of the tropical squid sepioteuthis lessoniana (cephalopoda: Loliginidae): An experimental approach. Marine Biology, 138(4) 819-825. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Juvenile squids were grown in individual 2.6-1 floating enclosures and were fed either a high- or a low-ration diet of fish and the crustacean Acetes. Squids were maintained for a maximum of 44 days in two experiments. The high-ration individuals reached a significantly larger size in both experiments (27, 25.5 mm mean mantle length, ML) compared to their low-ration siblings (19 mm mean ML) in both experiments. The statolith increment widths prior to the start of the experiment were significantly wider (between 3 and 4 mu m) compared to the increment widths after the start of the experiment (between 2 and 3 mu m) both for the low- and the high-ration squids. High-ration squids also had significantly wider increments and larger statoliths than their low-ration siblings. Even though we detected consistent trends in daily statolith increment widths for the different feeding regimes, we could not detect variation in increment widths at a daily level of resolution (i.e. as a result of differences in day-to-day food intake at an individual level). This was probably due to the relatively consistent diet experienced by each individual. These experiments revealed that ration level influences squid growth rate, statolith size and daily statolith increment width.
Jaruwat Nabhitabhata, Panya Asawangkune, Sabaithip Amornjaruchit, Pichitra Promboon, Phuket Marine Biological Cent. (Thailand), & Suganthi Devadason Marine Research Inst. (SDMRI), Tuticorin (India). (2001). In Hylleberg J. (Ed.), Tolerance of eggs and hatchlings of neritic cephalopods to salinity changes. Retrieved August 2, 2006, from [url="http://www.csa.com/"]www.csa.com[/url]
Hatching of eggs of two species of neritic cephalopods, the bigfin squid (Sepioteuthis lessoniana) and pharaoh cuttlefish (Sepia pharaonis) differed significantly following brief immersion at eight levels of salinity, 12-44 ppt at 4 ppt intervals. More than 80% of eggs of both species hatched in 24, 28 and 32 ppt as did cuttlefish eggs at 36 ppt. Bigfin squid eggs failed to hatch in 12 and 40 ppt and eggs of cuttlefish failed to hatch in 16, 20, 40 and 44 ppt. Optimum salinity range for hatching was estimated at 21.8-36.6 ppt for bigfin squid and 22.5-37.5 ppt for cuttlefish. Outside the optimum range, the salinity tended to cause premature hatching, death of the embryos before organogenesis at high salinity, and abnormal development at low salinity. Survival of hatchlings of both species differed significantly after brief change to the eight levels of salinity in 24 hrs. The highest survival was in 28 and 32 ppt for bigfin squids (more than 70%) and in 24, 28, 32 and 36 ppt for cuttlefish (more than 80%). The range of optimum salinity for the survival was 23.2-35.5 ppt for bigfin squid and 21.4-39.4 ppt for pharaoh cuttlefish. Survival during gradual change of salinity was similar to that following sudden change. The benthic cuttlefish tolerated low salinity better than planktonic squid. Short-term immersion of hatchlings in salinities outside the optimum range, within the tolerable time, may be applied in control and treatment of diseases and parasites in aquaculture.
Koyama, J., Nanamori, N., & Segawa, S. (2000). Bioaccumulation of waterborne and dietary cadmium by oval squid, sepioteuthis lessoniana, and its distribution among organs. Marine pollution bulletin, 40(11) 961-967. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Bioaccumulation of cadmium (Cd) by oval squid, Sepioteuthis lessoniana, the relative contributions of Cd in water and food to bioaccumulation, and the distribution of cadmium among organs were studied. In a bioconcentration test, oval squid was exposed to 0.2 mg Cd/l seawater for 14 days, then was reared in Cd-free seawater for 14 days. After the exposure and elimination periods, the Cd concentrations in the whole body were 3.10 plus or minus 0.18 and 1.90 plus or minus 0.05 mu g/g wet weight (ww), respectively. The bioconcentration factor (BCF) was 15.5 after exposure for 14 days. The liver exhibited the highest Cd concentration (49.3 mu g/g ww), and had the highest proportion of organ Cd content (42.8%) to whole-body burden at the end of the exposure period. In a biomagnification test, oval squid was exposed to 0.12 mg Cd/l seawater for 15 days and was simultaneously fed mummichog, Fundulus heteroclitus, that were simultaneously exposed to the same Cd concentration. For a further eight days the squid was kept in Cd-free seawater and was fed mummichog that were also kept in Cd-free seawater. After the exposure and elimination periods, the Cd concentrations in the whole body were 4.18 plus or minus 0.69 and 2.80 plus or minus 0.44 mu g/g ww, respectively. The concentration of whole-body Cd in the oval squid that was derived from water was estimated at 1.86 mu g/g ww after calculation of a BCF from the bioconcentration test. The contribution of Cd derived from water to the whole-body Cd burden appeared similar to that of the Cd derived from food. In the biomagnification test, the liver Cd concentration (58.8 mu g/g ww) and its proportion of the whole-body Cd concentration (40.6%) were the highest among those of all the organs after exposure for 15 days, regardless of the uptake route. Because wild squid seem to be exposed to much lower Cd concentrations in water and are subjected to similar Cd concentrations in their prey, compared with squid of the present study, the main Cd source for squid would appear to be dietary.
Mhitu, H., Mgaya, Y., Ngoile, M., Western Indian Ocean Marine Science Association, Zanzibar (Tanzania), & Institute of Marine Sciences, Zanzibar (Tanzania) University of Dar es Salaam. (2001). In Richmond M. D., Francis J.(Eds.), Growth and reproduction of the big fin squid, sepioteuthis lessoniana, in the coastal waters of zanzibar. Zanzibar (Tanzania): IMS/WIOMSA. Retrieved August 2, 2006, from [url="http://www.csa.com/"]www.csa.com[/url]
Aspects of growth and reproduction of the bigfin reef squid Sepioteuthis lessoniana (Lesson, 1830) in the coastal waters of Zanzibar were investigated with a view to obtaining basic information that could be used in the management of the squid fishery in the area. A total of 664 specimens, comprising 344 females and 320 males, were collected between April 1994 and March 1995. The size of individuals ranged from 63 mm to 347 mm and 72 mm to 277 mm dorsal mantle length (DML) for males and females respectively. Growth was not significantly different (p > 0.001) between males and females as revealed by length (L)-weight (W) relationship, thus the following expression was used to describe the growth of S. lessoniana; W = 0.0005 L super(2.255). Both males and females exhibited allometric growth. Gonad maturation, as revealed by maturity stages and indices, peaked in July, indicating that spawning period begins around July. Size at maturity was determined by statistical and graphical methods. Size (DML plus or minus 95 CL) at maturity as determined by the statistical method was 138.9 plus or minus 6.4 mm and 162 plus or minus 4.3 mm for males and females respectively, while the graphical method yielded 149.5 mm for males and 162.8 mm for females. Fecundity for female individuals ranged from 180 to 1180 eggs with a mean of 680 eggs for individuals of size range 140-249 mm DML.
Pecl, G. (2001). Flexible reproductive strategies in tropical and temperate sepioteuthis squids. Mar.Biol, 138(1) 93-101. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
A major difficulty confronting the determination of cephalopod reproductive life history is assessing over what portion of the life span an individual is reproductively mature and actively depositing eggs. This paper assesses the potential of the tropical Sepioteuthis lessoniana and two genetic types of the temperate Sepioteuthis australis, to spawn multiple batches of eggs at discrete times throughout the adult life span. This is achieved by histological examination of the ovarian gametogenic cycle and detailed morphological assessments of the reproductive system, in conjunction with other biological information. The genetic type of S. australis found at the northern limits of its Australian distribution showed evidence of a high correlation between body size and quantity of mature eggs, suggesting that eggs may be accumulating to be laid in a single batch. Although maturation was also a sizerelated process in S. lessoniana and Tasmanian S. australis, oviduct size was not correlated with body weight in mature females, which is indicative of multiple spawning. Further supporting evidence includes relatively low gonadosomatic indices, the heavier weight of the ovary relative to the oviduct, and the feeding activity of mature animals. Mature S. lessoniana and S. australis individuals were present at each location over very wide age and size ranges. In Tasmanian waters, there were distinct seasonal differences in the reproductive biology of S. australis. Summer-caught individuals had much higher gonadosomatic indices and may have been laying larger batches of eggs compared with winter-caught individuals. Summer-caught females also showed a negative correlation between egg size and egg number within the oviduct, suggesting that some individuals were producing fewer, larger eggs and others many smaller eggs. Evidence suggests that considerable flexibility is inherent in the reproductive strategy of both S. lessoniana and S. australis.
Pratoomchat, B., Natsukari, Y., Miki, I., & Chalermwat, K. (2001). Allozyme determination of genetic diversity in japanese and thai populations of oval squid (sepioteuthis lessoniana lesson, 1830). Umi/la mer, 39(3) 133-139. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Genetic variation and genotypic population structure of two geographic populations of oval squid (Sepioteuthis lessoniana Lesson, 1830), captured from Nagasaki (Japan) and Rayong (Thailand) were investigated using multi-locus allozyme analysis. On the basis of 22 loci screened, the percentage of polymorphic loci and observed heterozygosity were 45.45% and 0.28 for Japanese and 50.00% and 0.23 for Thai populations, respectively. These results suggest relatively high genetic distances between these population were observed (D=0.003). A lack of genetic differentiation between the Japanese and Thai populations of S. lessoniana suggests a panmictic gene pool of S. lessoniana over a wide geographic area.
Samuel, V. D., & Patterson, J. (2002). Intercapsular embryonic development of the big fin squid sepioteuthis lessoniana (loliginidae). Indian Journal of Marine Sciences, 31(2) 150-152. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
The egg masses of big fin squid, Sepioteuthis lessoniana were collected from the wild and their intercapsular embryonic development was studied. The average incubation period of the egg varied between 18-20 days. The cleavage started on the first day and the mantle developed between third and fifth day. The yolk started decreasing eighth day onwards. The tentacles with the sucker primordia on the tip were prominent from tenth day. The yolk totally reduced between thirteenth and seventeenth day and the paralarvae hatched out on eighteenth day. The developmental stages of the embryo inside the capsules during the incubation period is understood.
Semmens, J. M. (2002). Changes in the digestive gland of the loliginid squid sepioteuthis lessoniana (lesson 1830) associated with feeding. Journal of experimental marine biology and ecology, 274(1) 19-39. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Changes associated with feeding in the histological and cytological structure of the digestive gland of the loliginid squid Sepioteuthis lessoniana were examined, along with the nature of both the intracellular and extracellular enzymes produced by the gland. The timing of the release of the extracellular enzymes during the digestive cycle was also determined using a quantitative experimental program. Like that of all coleoid cephalopods, the digestive gland was characterised by one type of cell with several functional stages. As is the case for other loliginid squids, however, the digestive cells did not contain the large enzyme-carrying boules that characterise the digestive glands of most cephalopods. Instead, smaller secretory granules were found in the digestive cells and these may be the enzyme carriers. The prominent rough endoplasmic reticulum, large mitochondria and active Golgi complexes present in the digestive cells are characteristic of cephalopods and indicate a high metabolic activity. Like that of other cephalopods, endocytotic absorption of nutrients and intracellular digestion occurs in the digestive gland of this squid. From quantitative and qualitative examinations of structural changes in the digestive gland of S. lessoniana after feeding, a schedule of its function during the course of digestion was proposed. This indicated that digestion was very rapid, being completed in as little as 4 h in S. lessoniana. Extracellular digestive enzymes were only released after the first hour following feeding, which implies that they are stored in the stomach between meals to increase digestive efficiency.
Sharifuddin Bin Andy Omar, Danakusumah, E., Rani, C., Siswanto, E., Hade, A., & Phuket Marine Biological Cent. (Thailand) et al. (2001). In Hylleberg J. (Ed.), Incubation period and hatching rate of bigfin squid, sepioteuthis lessoniana, in 24 to 38 ppt salinity. Retrieved August 2, 2006, from [url="http://www.csa.com/"]www.csa.com[/url]
Together with Sepiella inermis and Loligo spp., the bigfin squid Sepioteuthis lessoniana (Lesson, 1830) is one of the important species, which have high value in Indonesia. In the present study, the effect of salinity on the incubation period and hatching rate of S. lessoniana was done at the Bojonegara Research Station for Coastal Aquaculture, Indonesia in 2000. Squid eggs were collected from Banten Bay waters. Eight salinities from 24-38 ppt were tested at 2 ppt intervals. 40 ppt salinity was lethal. The highest hatching rate (97%) was found in 32 ppt and the lowest (20%) in 38 ppt. The mantle length of the larvae ranged from 5.29 to 5.91 mm and the weight from 0.028 to 0.031 g.
Shuichi Shigeno, Kotaro Tsuchiya, & Susumu Segawa. (2001). Conserved topological patterns and heterochronies in loliginid cephalopods: Comparative developmental morphology of the oval squid sepioteuthis lessoniana. Invertebrate reproduction and development, 39(3) 161-174. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Development of the oval squid Sepioteuthis lessoniana is marked by a large embryonic size resulting in the most fully developed planktonic hatchlings within loliginids. We analyzed the embryonic development with special reference to the external morphology and the surface ultrastructure with a scanning electron microscope to identify both phylogenetic conservation and diversity of structures in the organogenesis of a loliginid. Developmental states of various cilia, namely the scattered, tuft, and uniform types are described. The ciliature pattern of S. lessoniana is more closely similar to the patterns of other loliginids than to those of sepioids and sepiolids, although characteristic numerous uniform-type cilia exist in the embryos of S. lessoniana. The conserved pattern can be recognized in the oganogenesis of S. lessoniana and other loliginids; on the other hand, heterochronic variations are noted, particularly in photosensitive organs and chromatophores. Eye pigmentation does not start at the same stage as in other loliginids and it is unlikely that the heterochronic variation of eye pigmentation is correlated to embryonic size. Chromatophores of S. lessoniana appeared earlier than those of other loliginids. Although hatchlings of S. lessoniana have a more strongly developed arm crown than other loliginids, the suckers arise at similar stages. These ontogenetic variations in loliginids may be considered together with the early mode of life.
Thompson, J. T., & Kier, W. M. (2002). Ontogeny of squid mantle function: Changes in the mechanics of escape-jet locomotion in the oval squid, sepioteuthis lessoniana lesson, 1830. Biological Bulletin, Marine Biological Laboratory, Woods Hole, 203(1) 14-26. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
In Sepioteuthis lessoniana, the oval squid, ontogenetic changes in the kinematics of the mantle during escape-jet locomotion imply a decline in the relative mass flux of the escape jet and may affect the peak weight-specific thrust of the escape jet. To examine the relationship between ontogenetic changes in the kinematics of the mantle and the thrust generated during the escape jet, we simultaneously measured the peak thrust and the kinematics of the mantle of squid tethered to a force transducer. We tested an ontogenetic series of S. lessoniana that ranged in size from 5 to 40 mm dorsal mantle length (DML). In newly hatched squids, thrust peaked 40 ms after the start of the escape jet and reached a maximum of between 0.10 mN and 0.80 mN. In the largest animals, thrust peaked 70 ms after the start of the escape jet and reached a maximum of between 18 mN and 110 mN. Peak thrust was normalized by the wet weight of the squid and also by the cross-sectional area of the circumferential muscle that provides power for the escape jet. The weight-specific peak thrust of the escape jet averaged 0.36 in newly hatched squid and increased significantly to an average of 1.5 in the largest squids measured (P < 0.01). The thrust per unit area of circumferential muscle averaged 0.25 mN/mm super(2) in hatchlings and increased significantly to an average of 1.4 mN /mm super(2) in the largest animals tested (P < 0.01). The impulse of the escape jet was also lowest in newly hatched individuals (1.3 mN times s) and increased significantly to 1000 mN times s in the largest squids measured (P < 0.01). These ontogenetic changes in the mechanics of the escape jet suggest (1) that propulsion efficiency of the exhalant phase of the jet is highest in hatchlings, and (2) that the mechanics of the circumferential muscles of the mantle change during growth.
Thompson, J. T., & Kier, W. M. (2001). Ontogenetic changes in fibrous connective tissue organization in the oval squid, sepioteuthis lessoniana lesson, 1830. Biological Bulletin, Marine Biological Laboratory, Woods Hole, 201(2) 136-153. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Ontogenetic changes in the organization and volume fraction of collagenous connective tissues were examined in the mantle of Sepioteuthis lessoniana, the oval squid. Outer tunic fiber angle (the angle of a tunic collagen fiber relative to the long axis of the squid) decreased from 33.5 degree in newly hatched animals to 17.7 degree in the largest animals studied. The arrangement of intramuscular collagen fiber systems 1 (IM-1) and 2 (IM-2) also changed significantly during ontogeny. Because of the oblique trajectory of the IM-1 collagen fibers, two fiber angles were needed to describe their organization: (1) IM-1 sub(SAG), the angle of an IM-1 collagen fiber relative to the squid's long axis when viewed from a sagittal plane and (2) IM-1 sub(TAN), the angle of an IM-1 collagen fiber relative to the squid's long axis when viewed from a plane tangential to the outer curvature of the mantle. The sagittal component (IM-1 sub(SAG)) of the IM-1 collagen fiber angle was lowest in hatchling squid (32.7 degree ) and increased exponentially during growth to 43 degree in squid with a dorsal mantle length (DML) of 15 mm. In squid larger than 15 mm DML, IM-1 sub(SAG) fiber angle did not change. The tangential component (IM-1 sub(TAN)) of IM-1 collagen fiber angle was highest in hatchling squid (39 degree ) and decreased to 32 degree in the largest squid examined. IM-2 collagen fiber angle (the angle of an IM-2 collagen fiber relative to the outer surface of the mantle) was lowest in hatchling squid (34.6 degree ) and increased exponentially to about 50 degree in 15-mm DML animals. In squid larger than 15 mm DML, IM-2 fiber angle increased slightly with size. The volume fraction of collagen in IM-1 and IM-2 increased 68 and 36 times, respectively, during growth. The ontogenetic changes in the organization of collagen fibers in the outer tunic, IM-1, and IM-2 may lead to ontogenetic differences in the kinematics of mantle movement and in elastic energy storage during jet locomotion.
Thompson, J. T., & Kier, W. M. (2001). Ontogenetic changes in mantle kinematics during escape-jet locomotion in the oval squid, sepioteuthis lessoniana lesson, 1830. Biological Bulletin, Marine Biological Laboratory, Woods Hole, 201(2) 154-166. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
We investigated the kinematics of mantle movement during escape jet behavior in an ontogenetic series of Sepioteuthis lessoniana, the oval squid. Changes in mantle diameter during the jet were measured from digitized S-VHS video fields of tethered animals that ranged in age from hatchlings to 9 weeks. The amplitude of both mantle contraction and mantle hyperinflation (expressed as percent change from the resting mantle diameter) during an escape jet was significantly greater in hatchlings than in older, larger squid (P < 0.05). The maximum amplitude of mantle contraction during the escape jet decreased from an average of -40% in hatchlings to -30% in the largest animals studied. The maximum amplitude of mantle hyperinflation decreased from an average of 18% in hatchlings to 9% in the largest squid examined. In addition, the maximum rate of mantle contraction decreased significantly during ontogeny (P < 0.05), from a maximum of 8.6 mantle circumference lengths per second (L/s) in hatchlings to 3.8 L/s in the largest animals studied. The ontogenetic changes in the mantle kinematics of the escape jet occurred concomitantly with changes in the organization of collagenous connective tissue fiber networks in the mantle. The alteration in mantle kinematics during growth may result in proportionately greater mass flux during the escape jet in newly hatched squid than in larger animals.
Thompson, J. T., & Kier, W. M. (2006). Ontogeny of mantle musculature and implications for jet locomotion in oval squid sepioteuthis lessoniana. Journal of Experimental Biology, 209(3) 433-443. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
We examined the relationship between mantle muscle structure and mantle kinematics in an ontogenetic series (5-85 mm dorsal mantle length) of oval squid, Sepioteuthis lessoniana. Thick filament length increased during growth in the mantle muscle fibres that power jet locomotion (i.e. the circular muscles). The thick filament length of both the superficial mitochondria-rich (SMR; analogous to vertebrate red muscle fibres) and central mitochondria-poor (CMP; analogous to vertebrate white muscle fibres) circular muscles increased significantly during ontogeny. Thick filaments in the SMR circular muscle fibres of newly hatched squid (N=5) ranged from 0.7 to 1.4 mu m and averaged 1.0 mu m, while the thick filaments of the SMR fibres of the largest squids (N=4) studied ranged from 1.2 to 3.4 mu m and averaged 1.9 mu m. The ontogeny of thick filament length in the CMP circular muscle fibres showed a similar trend. The range for hatchling CMP circular muscles was 0.7-1.4 mu m, with an average of 1.0 mu m, whereas the range and average for the largest squids studied were 0.9-2.2 mu m and 1.5 mu m, respectively. Within an individual hatchling, we noted no significant differences between the thick filament lengths of the SMR and CMP fibres. Within an individual juvenile, the thick filaments of the SMR fibres were similar to 25% longer than the CMP fibres. The change in thick filament length may alter the contractile properties of the circular muscles and may also result in a decrease in the rate of mantle contraction during jetting. In escape-jet locomotion, the maximum rate of mantle contraction was highest in newly hatched squid and declined during ontogeny. The maximum rate of mantle contraction varied from 7-13 muscle lengths per second in newly hatched squid (N=14) and from 3-5 muscle lengths per second in the largest squids (N=35) studied.
Tokai, T., & Ueta, Y. (2002). Size selectivity of squid jig for oval squid sepioteuthis lessoniana, and its relationship to prey-size selectivity. Bulletin of Marine Science, 71(2) 1141-1142. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Squid jigging and small sized set net fisheries catch the oval squid Sepioteuthis lessoniana in the coastal waters along the Pacific Ocean coast of Tokushima Prefecture, Japan. Most squid jigs used there are ready-made, colored, and prawn-shaped lures with a double ring of barbless hooks, and their body lengths (length of shrimp-shaped part of the jig, apart from the hooks) are about 12 cm. In this study, the set nets were regarded as a non-selective fishing gear due to the small enough mesh of the net, and their catch as a representative of the size frequency of the squid population in the fishing area. Size selectivity curve of squid-jig fisheries was estimated with the extended SELECT (Share Each LEngth's Catch Total) analysis model by comparing the size distributions of catches by squid-jigs and by set-nets carried out simultaneously in the same fishing area. As a result, size-selectivity r(l) in the squid jig size was expressed as a logistic function of mantle length l, r(l) = exp (-10.0 + 0.485 l) / [1 + exp(-10.0 + 0.485 l)]. From these logistic-parameter estimates, retention probability of the oval squid of 12cm mantle length was calculated to be 1.5 %. This implies that oval squid of smaller size than the jig of 12cm body length were not caught by the squid jig. In general, before squid seizes prey with its tentacles and arms the squid judges with their high visual acuity whether the prey size is appropriate or not. In rearing experiments, oval squid were most likely to attack a prey smaller than their body size, and when the squid seized a little larger prey they often discarded parts of the prey. In contrast, oval squid of a small size were often preyed on by rudder-fish Girella punctata of a size larger than the squid. Thus, oval squid appeared to feed on prey of a size smaller or a size relative to their own body size and may be unable, or select not, to attack prey larger than their own body size. These mean that oval squid have prey-size selectivity. For squid jigging to succeed, the squid must attack the jig as it would a prey; therefore a likely explanation of the squid jig size-selectivity found here is that it is a type of prey-size selectivity by the oval squid.
Triantafillos, L., & Adams, M. (2005). Genetic evidence that the northern calamary, sepioteuthis lessoniana, is a species complex in australian waters. ICES Journal of Marine Science, 62(8) 1665-1670. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Allozyme electrophoresis was used to investigate the taxonomic status of northern calamary Sepioteuthis lessoniana (Lesson 1830) from two sites in Shark Bay, Western Australia. Of the 40 squid examined at 38 presumptive loci, four individuals from the oceanic site were clearly differentiated from the rest by fixed allelic differences at four loci (Acp, Got2, Idh2, and PepD) and near-fixed differences at another three (Est, Ocdh, and 6Pgd). The genetic distances between these two groups of individuals (13% Fixed Differences and Nei, D (1978)=0.178) were roughly twofold greater than those between the two cryptic taxa in the southern calamary S. australis, but are considerably smaller than those between the northern and southern calamary. The most likely explanation for these data is that S. lessoniana comprises two ''cryptic'' biological species in this region. Further studies are needed to delineate the total number of species found throughout Australasia for this important loliginid squid.
Walsh, L. S., Turk, P. E., & Lee, P. G. (2002). Mariculture of the loliginid squid sepioteuthis lessoniana through seven successive generations. Aquaculture, 212(1-4) 245-262. Retrieved August 2, 2006, from the ASFA: Aquatic Sciences and Fisheries Abstracts database.
Sepioteuthis lessoniana is a commercially important squid throughout the Indo-West Pacific and is a useful species in biomedical research. It has now been cultured through seven successive generations in closed, recirculating seawater systems. Egg viability was highest in the parental generation (34.9%) and significantly decreased in the next six generations with a viability rate of 1.56-13%. The highest hatchling survival was in G4 (80.3%) and the lowest was in G3 (26.3%). Water quality was maintained at acceptable levels during each successive generation (NH40.1 ppm, NO20.05 ppm, NO350 ppm, pH>8.0). Life spans ranged from 169 to 262 days (5.6-8.7 months) with a mean of 208 days (6.9 months). The seven generations reached mean adult sizes at 500-900 g. The age of sexual maturity for females was recorded for all populations except G6 and ranged from 146 to 224 days (4.9-7.5 months) with an average of 171 days (5.7 months). Sex ratios did not consistently vary from 1:1 in any generation. Live food (i.e., crustaceans and fish) was the only food supplied throughout their life cycle.