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Inter-annual plasticity of squid life history
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Inter-annual plasticity of squid life history and population

structure: ecological and management implications




Oecologia (2004) 139: 515–524



G. T. Pecl . N. A. Moltschaniwskyj . S. R. Tracey .

A. R. Jordan



ABSTRACT



Abstract Population size and structure, as well as

individual growth rates, condition, and reproductive

output, respond to environmental factors, particularly in

short-lived and fast-growing squid species. We need to

understand the mechanisms through which populations

respond to environmental conditions, to predict when or if

established relationships, used as management tools to

forecast recruitment strength, might break down completely.

Identifying characteristics of successful recruits who

have grown under different environmental scenarios may

improve our understanding of the mechanistic connections

between environmental conditions and the temporal

variation in life history characteristics that ultimately

affect recruitment. This 5-year study sought to determine

the association between key life history characteristics of

southern calamary Sepioteuthis australis (growth rate,

body size, and patterns of repro-somatic energy allocation)

and the environmental conditions experienced by individuals

on the east coast of Tasmania, Australia. Among

years, all population and individual parameters examined

were highly variable, despite the environmental regime

during the study not encompassing the extremes that may

occur in this dynamic region. Temperature was not clearly

associated with any of the individual or population

differences observed. Populations of apparently similar

abundance were composed of individuals with strikingly

different biological characteristics, therefore seeking

relationships between abundance and environmental parameters

at gross levels did not shed light on the

mechanisms responsible for population size. Importantly,

inter-annual differences in squid size, condition, reproductive

investment, and possibly growth rate, were sexspecific,

indicating that males and females responded

differently to similar factors. Among years differences in

body size were extreme, both among the male component

of the population and between genders. The relative

importance of many size-based processes that contribute to

population size and structure (e.g. predation, starvation,

competition, and reproductive success) will therefore vary

inter-annually.



Keywords Temporal variability . Growth . Environment recruitment

. Reproduction . Condition


Attached Files
.pdf   Erratum_Final_Oecologia.pdf (Size: 33.04 KB / Downloads: 891)
.pdf   Pecl_et_al_2004_Oecologia.pdf (Size: 294.74 KB / Downloads: 2,285)
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