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The role of hatchling size in generating the intrinsic size-at-age variability of cephalopods: extending the Forsythe Hypothesis

Citation

Pecl, GT and Steer, MA and Hodgson, K, The role of hatchling size in generating the intrinsic size-at-age variability of cephalopods: extending the Forsythe Hypothesis, Marine and Freshwater Research, 55, (4) pp. 387-394. ISSN 1323-1650 (2004) [Refereed Article]

DOI: doi:10.1071/MF03153

Abstract

Cephalopods are characterised by extreme variability in size-at-age, with much of this variation attributed to effects of temperature and food. However, even siblings reared under identical conditions display a wide range of sizes after a period of growth. Hatchling size may represent a source of variation encompassed within adult size-at-age data (i) within a given cohort (variation in hatchling size suggests that a cohort's growth trajectory will have a 'staggered start') and (ii) as hatchling size also varies as a function of incubation temperature this will vary across broader scales (i.e. between cohorts). Field-hatchling size data for Sepioteuthis australis were used in simple deterministic simulations, extending Forsythe's (1993) temperature hypothesis, to investigate the influence of hatchling size on adult size-at-age variability. Within a cohort, our growth projections suggest that after 90 days, a large hatchling growing at a specific constant percentage daily growth rate (% BW day-1), would be approximately double the size of the small hatchling growing at exactly the same rate, irrespective of the growth rate used. When considering growth of different cohorts, decreases in hatchling size, as temperatures increase during a spring/summer spawning season, may be partially counteracting the 'Forsythe-effect' of increased growth rate at higher temperatures.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Population Ecology
Objective Division:Environment
Objective Group:Flora, Fauna and Biodiversity
Objective Field:Marine Flora, Fauna and Biodiversity
Author:Pecl, GT (Professor Gretta Pecl)
Author:Steer, MA (Dr Michael Steer)
Author:Hodgson, K (Ms Kate Hodgson)
ID Code:31511
Year Published:2004
Web of Science® Times Cited:32
Deposited By:TAFI - Marine Research Laboratory
Deposited On:2004-08-01
Last Modified:2005-04-06
Downloads:0

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