18-01-2007, 06:15 AM
[quote name='scifly' post='7908' date='Jan 8 2007, 12:09 AM']Hi Jon
Sounds like you are having a ripe old time of it. By way of introduction, I completed a Masters degree on chokka squid (previously Loligo vulgaris reynaudii, now L. reynaudii) in South Africa so got to learn a bit about the little critters. As you know, jigging in South Africa is via hand jig with a heavy lead jig on the bottom and one or two plastic "floaters" higher up the line. You seem to have been doing everything right. There have been a lot of papers written on the dynamics of the fishing aggregations (SA fishers target spawning aggregations of squid) and a good link to info is here [url="http://www.oceanafrica.com/publications/"]http://www.oceanafrica.com/publications/[/url]. You are quite right that the squid will move away from dirty water and in SA, fishers often look for deeper spawning squid by using drogues or parachutes to drift over deeper reefs. Another question: have you made use of a sounder to look for aggregations? Chokka typically formed a mushroom shaped signature on the sounder or else a plume from the bottom towards the surface. Any other specific questions shoot them my way and I may be able to help. Graham Pierce at the University of Aberdeen is probably quite a good contact to talk to as is Peter Boyle.
Regards
Len[/quote]
Hi Scifly,
sounds like you have studied in far greater detail the same fishery i had a look at back in October. We were invited (a colleague of mine from CEFAS and a representative from the SEAFISH industry authority) by a producer (Christy's and sons) in St Francis Bay and are currently trying to develop the methods used over there in an English environment. Several limitations apply not least funding but 20 days have been identified and we have thus far conducted 11, with some limited success.
Two main species that make up the squid landings here in the SW are L.Forbesi and L.Vulgaris and we have caught both species on jigs. Of course this in itself proves nothing as there has existed in the SW for 20-30 years an artisanal inshore jig fishery. This fishery reflects the erratic nature of squid abundance and those that exploit this fishery do so in conjunction with line fishing for Mackerel (S. scombre), potting for crab and lobster and gill netting for mixed species, tending to target squid only when the conditions are just right. This fishery has more often than not targetted large males of both species over rough ground and known reefs and from our catches in these areas the majority of fish would seem to be large "bull" males, often >50cm. Another characteristic of this fishery is that very little squid is caught through the day, the most productive times being first and last light. Our survey so far seems to supports this, L.Forbesi being particularly scarce during the night whereas L.Vulgaris seems easier to catch at night.
As you will be aware the SA fleet are equipped with Japanese squid lights and an average vessel typically burns around 50-60,000watts of metal halide light. The cost of this would be prohibitive to the survey funding so we have attempted to compromise by hiring a generator/light rig of the type commonly seen illuminating roadworks here in the UK. This we have situated on the stern of the chartered fishing vessel where we can play with the light and shadow characteristics by raising and lowering the telescopic lighting head. The head consists of 4x1000watt lamps and although this is very much smaller (by at least a factor of 10) and directional in
nature where the Japanese lights are none directional this set up still provides us with brighter lights than conventional deck lighting.
Abundance of squid is, i believe, far less than in SA and we have not yet discovered any "nests". I have fished from the SW for 20 years before working for CEFAS and in that time i have not witnessed nor do i know of anyone who has witnessed a "nest" of squid, although static gear fishermen are often aware of increases or decreases in squid breeding as the eggs are often secreted to their pots and ropes.
It is entirely possible that the L.Vulgaris is to be found in small highly mobile hunting/sexually orientated packs and our limited experiences of catching squid at night under lights sort of supports this. Also L.Forbesi has much smaller eye than L.Vulgaris and i wonder if this goes someway to explain why L.Forbesi is not caught at night.
More questions than answers. Bloody squid!!
Thanks for link has proven very interesting.
Regards Jon
Sounds like you are having a ripe old time of it. By way of introduction, I completed a Masters degree on chokka squid (previously Loligo vulgaris reynaudii, now L. reynaudii) in South Africa so got to learn a bit about the little critters. As you know, jigging in South Africa is via hand jig with a heavy lead jig on the bottom and one or two plastic "floaters" higher up the line. You seem to have been doing everything right. There have been a lot of papers written on the dynamics of the fishing aggregations (SA fishers target spawning aggregations of squid) and a good link to info is here [url="http://www.oceanafrica.com/publications/"]http://www.oceanafrica.com/publications/[/url]. You are quite right that the squid will move away from dirty water and in SA, fishers often look for deeper spawning squid by using drogues or parachutes to drift over deeper reefs. Another question: have you made use of a sounder to look for aggregations? Chokka typically formed a mushroom shaped signature on the sounder or else a plume from the bottom towards the surface. Any other specific questions shoot them my way and I may be able to help. Graham Pierce at the University of Aberdeen is probably quite a good contact to talk to as is Peter Boyle.
Regards
Len[/quote]
Hi Scifly,
sounds like you have studied in far greater detail the same fishery i had a look at back in October. We were invited (a colleague of mine from CEFAS and a representative from the SEAFISH industry authority) by a producer (Christy's and sons) in St Francis Bay and are currently trying to develop the methods used over there in an English environment. Several limitations apply not least funding but 20 days have been identified and we have thus far conducted 11, with some limited success.
Two main species that make up the squid landings here in the SW are L.Forbesi and L.Vulgaris and we have caught both species on jigs. Of course this in itself proves nothing as there has existed in the SW for 20-30 years an artisanal inshore jig fishery. This fishery reflects the erratic nature of squid abundance and those that exploit this fishery do so in conjunction with line fishing for Mackerel (S. scombre), potting for crab and lobster and gill netting for mixed species, tending to target squid only when the conditions are just right. This fishery has more often than not targetted large males of both species over rough ground and known reefs and from our catches in these areas the majority of fish would seem to be large "bull" males, often >50cm. Another characteristic of this fishery is that very little squid is caught through the day, the most productive times being first and last light. Our survey so far seems to supports this, L.Forbesi being particularly scarce during the night whereas L.Vulgaris seems easier to catch at night.
As you will be aware the SA fleet are equipped with Japanese squid lights and an average vessel typically burns around 50-60,000watts of metal halide light. The cost of this would be prohibitive to the survey funding so we have attempted to compromise by hiring a generator/light rig of the type commonly seen illuminating roadworks here in the UK. This we have situated on the stern of the chartered fishing vessel where we can play with the light and shadow characteristics by raising and lowering the telescopic lighting head. The head consists of 4x1000watt lamps and although this is very much smaller (by at least a factor of 10) and directional in
nature where the Japanese lights are none directional this set up still provides us with brighter lights than conventional deck lighting.
Abundance of squid is, i believe, far less than in SA and we have not yet discovered any "nests". I have fished from the SW for 20 years before working for CEFAS and in that time i have not witnessed nor do i know of anyone who has witnessed a "nest" of squid, although static gear fishermen are often aware of increases or decreases in squid breeding as the eggs are often secreted to their pots and ropes.
It is entirely possible that the L.Vulgaris is to be found in small highly mobile hunting/sexually orientated packs and our limited experiences of catching squid at night under lights sort of supports this. Also L.Forbesi has much smaller eye than L.Vulgaris and i wonder if this goes someway to explain why L.Forbesi is not caught at night.
More questions than answers. Bloody squid!!
Thanks for link has proven very interesting.
Regards Jon