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Modelling size-at-age in wild immature female octopus: a bioenergetics approach


Andre, J and Pecl, GT and Grist, EPM and Semmens, JM and Haddon, M and Leporati, S, Modelling size-at-age in wild immature female octopus: a bioenergetics approach, Marine Ecology - Progress Series, 384, (May) pp. 159-174. ISSN 0171-8630 (2009) [Refereed Article]

DOI: doi:10.3354/meps08035


The population dynamics of cephalopods are poorly understood because intra-specific size-at-age is characteristically variable. Much of the variation observed is attributed to temperature and food, but other generally overlooked factors such as hatchling size and inherent growth capacities also affect size-at-age. In the present paper, we investigated the relative influence of the principal abiotic (environmental temperature) and biotic (food consumption, hatchling size, inherent growth capacity) factors affecting size-at-age in immature octopus. Using a bioenergetics model and size-at-age data of wild-caught immature Octopus pallidus, we simulated the juvenile growth trajectories of individuals hatched in different seasons (summer, autumn and winter) based on food availability, metabolism, environmental temperature and individual variability, under an assumption of 2- phase growth. Simulations predict that the effect of hatchling size on size-at-age was secondary to that of inherent growth capacity. Projections suggest that wild immature populations comprise a mixture of individuals displaying exponential growth and 2-phase growth and that the proportion of each depends primarily on the individuals' inherent growth capacities and food availability. High food intake was projected to decrease the number of individuals displaying 2-phase growth by delaying the transition between the 2 growth phases, resulting in larger individuals. Overall, individuals hatched in summer grew to larger sizes and matured earlier than individuals hatched in autumn or winter, independent of food availability. The size-at-age distribution of the summer and autumn cohorts tended to become bimodal under certain food intake levels, which highlights the importance of coupling size data with accurate age estimates in future octopus population studies.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Population ecology
Objective Division:Animal Production and Animal Primary Products
Objective Group:Fisheries - wild caught
Objective Field:Fisheries - wild caught not elsewhere classified
UTAS Author:Andre, J (Dr Jessica Andre)
UTAS Author:Pecl, GT (Professor Gretta Pecl)
UTAS Author:Semmens, JM (Professor Jayson Semmens)
UTAS Author:Leporati, S (Mr Stephen Leporati)
ID Code:58196
Year Published:2009
Web of Science® Times Cited:11
Deposited By:TAFI - Zoology
Deposited On:2009-09-15
Last Modified:2012-03-05

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