12-10-2004, 11:48 PM
The in situ relationships between season of hatching, growth and
condition in the southern calamary, Sepioteuthis australis
Gretta T. Pecl
Abstract. This paper examines seasonal patterns in growth and condition of Sepioteuthis australis from temperate waters of Tasmania, Australia. Growth was described by a power function and was fast for a temperate species, with
an average rate over the lifetime of 4ââ¬â5%BW dayâ1. Sepioteuthis australis is an annual species, however spawning and hatching of juveniles appears to occur all year round. Analysis of individual juvenile growth demonstrated a
correlation between seasonally increasing temperatures and progressively faster growth. Season of hatching also had a clear effect on adult growth; summer-hatched individuals were larger at 170ââ¬â190 days of age compared with
winter-hatched individuals (1002ñ98 g and 632ñ27 g respectively). The lengthââ¬âmantle weight relationship of adults was also dependent on season of hatching, with individuals hatched in summer and spring having heavier mantles at a given length than those hatched in winter or autumn. Differential rates of growth or varying levels of condition, or perhaps both, may affect the survivorship of individuals. Growth, condition and potentially lifespan of S. australis are dependent on environmental factors, with the dynamic nature of oceanographical conditions on the east coast of Tasmania resulting in a highly variable and fluctuating population structure.
Extra keywords: environment, growth plasticity, life-history, population structure, temperature.
condition in the southern calamary, Sepioteuthis australis
Gretta T. Pecl
Abstract. This paper examines seasonal patterns in growth and condition of Sepioteuthis australis from temperate waters of Tasmania, Australia. Growth was described by a power function and was fast for a temperate species, with
an average rate over the lifetime of 4ââ¬â5%BW dayâ1. Sepioteuthis australis is an annual species, however spawning and hatching of juveniles appears to occur all year round. Analysis of individual juvenile growth demonstrated a
correlation between seasonally increasing temperatures and progressively faster growth. Season of hatching also had a clear effect on adult growth; summer-hatched individuals were larger at 170ââ¬â190 days of age compared with
winter-hatched individuals (1002ñ98 g and 632ñ27 g respectively). The lengthââ¬âmantle weight relationship of adults was also dependent on season of hatching, with individuals hatched in summer and spring having heavier mantles at a given length than those hatched in winter or autumn. Differential rates of growth or varying levels of condition, or perhaps both, may affect the survivorship of individuals. Growth, condition and potentially lifespan of S. australis are dependent on environmental factors, with the dynamic nature of oceanographical conditions on the east coast of Tasmania resulting in a highly variable and fluctuating population structure.
Extra keywords: environment, growth plasticity, life-history, population structure, temperature.