The in situ relationships between season of hatching, growth and condition in the southern calamary, Sepioteuthis australis
Pecl, GT, The in situ relationships between season of hatching, growth and condition in the southern calamary, Sepioteuthis australis, Marine and Freshwater Research, 55, (4) pp. 429-438. ISSN 1323-1650 (2004) [Refereed Article]
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 4-5% BW day-1. 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 170-190 days of age compared with winter-hatched individuals (1002 ± 98 g and 632 ± 27 g respectively). The length-mantle 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.