Effects of temperature and food availability on larval cod survival: a model for behaviour in vertical gradients

N Fouzai,C Jørgensen,Ø Fiksen,AF Opdal

doi:10.3354/meps11326

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 529:199-212 (2015) - DOI: https://doi.org/10.3354/meps11326 Effects of temperature and food availability on larval cod survival: a model for behaviour in vertical gradients Nadia Fouzai1,*, Anders F. Opdal2, Christian Jørgensen2, Øyvind Fiksen1,2 1Department of Biology, University of Bergen, PO Box 7803, 5020 Bergen, Norway 2Uni Research, 5020 Bergen, Norway *Corresponding author: nadia.fouzai@bio.uib.no ABSTRACT: Recruitment success in living marine resources is variable due to high survival variability of early life stages. Improving our understanding of how environmental and ecological factors mechanistically interact and influence larval fish growth and survival is necessary to better predict year-class strength and expected physiological and behavioural responses to climate warming. We use a state-dependent optimality model for the behaviour of larval Atlantic cod Gadus morhua to analyse trade-offs related to growth and survival. Temperature-dependent maximum growth rates and vertical profiles of temperature and stochastic prey availability are used as inputs within a mechanistic modelling framework that finds optimal behavioural strategies of vertical migration and foraging activity. The fitness criterion used is maximization of survival probability until the larvae reach a given body size (15 mm). Detailed descriptions of predation, physiology, growth and survival of larval cod emerge from simulations of the optimal strategies. The model shows that the effect of temperature on survival is complex. Increasing temperature may lead to faster growth and higher survival, but only when there is sufficient food. In poor food environments, higher temperatures make larvae more susceptible to predation as they take higher risks to satisfy their metabolic costs. Overall, these results suggest that larval Atlantic cod, especially those from warmer-water stocks, may experience reduced survival and recruitment in climate-change scenarios that predict both elevated temperatures and reduced food supply. KEY WORDS: Larval cod · Optimal behaviour · Growth · Recruitment · Optimality model · Trade-off Full text in pdf format Supplementary material PreviousNextCite this article as: Fouzai N, Opdal AF, Jørgensen C, Fiksen Ø (2015) Effects of temperature and food availability on larval cod survival: a model for behaviour in vertical gradients. Mar Ecol Prog Ser 529:199-212. https://doi.org/10.3354/meps11326 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 529. Online publication date: June 08, 2015 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2015 Inter-Research.

Highlights

Climate change is an important driver of structure and dynamics in marine populations and ecosystems (Johnson et al 2011)
Higher temperatures make larvae more susceptible to predation as they take higher risks to satisfy their metabolic costs. These results suggest that larval Atlantic cod, especially those from warmer-water stocks, may experience reduced survival and recruitment in climate-change scenarios that predict both elevated temperatures and reduced food supply
The model is parameterized for larval Atlantic cod, but many of the resulting predictions can be generalized to species having pelagic larval stages that share the relevant characteristics of flexible behaviour, trade-offs between growth and survival, and high mortality rates

Summary

Introduction

Climate change is an important driver of structure and dynamics in marine populations and ecosystems (Johnson et al 2011). It can affect ecosystem productivity, phenology, species distributions and abundance (Perry et al 2005). There are several mechanisms, e.g. match or mismatch between first feeding larvae and their prey or predators (Cushing 1973, 1975, Anderson 1988, Bailey & Houde 1989), and retention processes during oceanic drift between spawning and nursery areas (Sinclair 1988), which may influence recruitment variability (Houde 2008). Small changes in food abundance or temperature conditions can positively or negatively impact the behaviour and survival of larval stages

Methods

Results

Conclusion