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ENERGETICS, PREDATION, AND RATION AFFECT SIZE-DEPENDENT GROWTH AND MORTALITY OF FISH DURING WINTER

ENERGETICS, PREDATION, AND RATION AFFECT SIZE-DEPENDENT GROWTH AND MORTALITY OF FISH DURING WINTER Winter temperatures may reduce energy costs for ectotherms. However, variable mid-temperate and low-latitude winters may interact with scaling of size, metabolism, and energy reserves to cause energy deficits and require trade-offs between foraging and predation. A dynamic optimization model explored how ration, fall fat, and both non- and size-selective predation influenced foraging (i.e., fast or forage) and energy allocation (i.e., length or fat) decisions that maximize winter survival of age-0 largemouth bass ( Micropterus salmoides ). During a mid-latitude (38°° N) winter, a pond experiment in which age-0 fish occurred with or without adult conspecific predators tested a subset of the model. In the model without predators, winter foraging occurred, with small size only reducing survival when low ration and low fall fat caused small fish to exhaust reserves. With predation, all sizes foraged to maintain mass and fat reserves when ration was sufficiently high, with small fish also growing in length. When modeled predation was nonselective, size-dependent mortality varied in complex ways. In contrast, size-selective predators consistently reduced survival of small fish. Generally consistent with the model, fish in ponds without predators gained mass and energy content, while those with predators only maintained these parameters. All small individuals grew more than large counterparts in length. Mortality in ponds never depended on size but was ∼∼20%% higher with predators. Energy deficits often demand active foraging during mid-temperate winters, with predation rather than energy depletion influencing size-dependent survival. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Ecology Ecological Society of America

ENERGETICS, PREDATION, AND RATION AFFECT SIZE-DEPENDENT GROWTH AND MORTALITY OF FISH DURING WINTER

Garvey, James E.; Ostrand, Kenneth G.; Wahl, David H.
Ecology , Volume 85 (10) – Oct 1, 2004
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References (52)

Publisher
Ecological Society of America
Copyright
Copyright © 2004 by the Ecological Society of America
Subject
Regular Article
ISSN
0012-9658
DOI
10.1890/03-0329
Publisher site
See Article on Publisher Site

Abstract

Winter temperatures may reduce energy costs for ectotherms. However, variable mid-temperate and low-latitude winters may interact with scaling of size, metabolism, and energy reserves to cause energy deficits and require trade-offs between foraging and predation. A dynamic optimization model explored how ration, fall fat, and both non- and size-selective predation influenced foraging (i.e., fast or forage) and energy allocation (i.e., length or fat) decisions that maximize winter survival of age-0 largemouth bass ( Micropterus salmoides ). During a mid-latitude (38°° N) winter, a pond experiment in which age-0 fish occurred with or without adult conspecific predators tested a subset of the model. In the model without predators, winter foraging occurred, with small size only reducing survival when low ration and low fall fat caused small fish to exhaust reserves. With predation, all sizes foraged to maintain mass and fat reserves when ration was sufficiently high, with small fish also growing in length. When modeled predation was nonselective, size-dependent mortality varied in complex ways. In contrast, size-selective predators consistently reduced survival of small fish. Generally consistent with the model, fish in ponds without predators gained mass and energy content, while those with predators only maintained these parameters. All small individuals grew more than large counterparts in length. Mortality in ponds never depended on size but was ∼∼20%% higher with predators. Energy deficits often demand active foraging during mid-temperate winters, with predation rather than energy depletion influencing size-dependent survival.

Journal

Ecology – Ecological Society of America

Published: Oct 1, 2004

Keywords: ectotherm ; fat ; growth ; largemouth bass ; length ; Micropterus salmoides ; predation ; survival ; winter

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