Size-dependent vulnerability of marine fish larvae to predation: An individual-based numerical experiment
- University of South Alabama, Mobile, AL (United States). Dept. of Marine Sciences
- Maryland Univ., Solomons, MD (United States). Chesapeake Biological Lab.
- Oak Ridge National Lab., TN (United States)
An individual-based predation model permitted 20-d simulations to be initiated with populations of individual theoretical'' ctenophore-, medusae-, and planktivorous fish-like predators and larvae prey that varied in size, growth rate, and swimming speed similarly to populations in the field. Results of predation experiments in 3.2 M{sup 3} mesocosms were used to estimate parameters in a Gerritsen-Strickler type encounter model which is embedded into the individual-based framework. Larval susceptibility with size also was estimated for each predator. Model simulations indicate that the relationship between larval size and vulnerability to predation, and ultimately cohort survival rate, depends upon attributes both of individual predators and larval prey and that bigger or faster growing larvae within a cohort are not always most likely to survive. Despite the finding that cohort-specific mortality generally decreased as the mean size (length) of the members of the cohort increased, mean size or growth rate of individual surviving larvae each day was lower or not significantly different from those that died in most simulations until larvae reached a size threshold when susceptibility decreased more rapidly with larval size than encounter rate increased. After the size threshold was reached, a switch'' occurred whereby predation began to select for survivors of longer mean length. The time necessary to reach the threshold depends on growth rate of the larvae, size of the predators and the variance structure of these parameters.
- Research Organization:
- Oak Ridge National Lab., TN (United States)
- Sponsoring Organization:
- USDOE; EPRI; National Science Foundation (NSF); USDOE, Washington, DC (United States); Electric Power Research Inst., Palo Alto, CA (United States); National Science Foundation, Washington, DC (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 7159942
- Report Number(s):
- CONF-9209228-1; ON: DE93000437; CNN: OCE-8701304; RP2932-2
- Resource Relation:
- Conference: 80. statutory meeting of the International Council for the Exploration of the Sea, Wassermunde (Germany), 24 Sep 1992
- Country of Publication:
- United States
- Language:
- English
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