Simulated Influences of Hatching-Date Dependent Survival on Year Class Composition and Abundance
Mark W.Rogers*, Micheal S.Allen
Identifiers and Pagination:Year: 2010
First Page: 169
Last Page: 179
Publisher Id: TOFISHSJ-3-169
Article History:Received Date: 18/10/2009
Revision Received Date: 19/05/2010
Acceptance Date: 19/05/2010
Electronic publication date: 11/10/2010
Collection year: 2010
open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: (https://creativecommons.org/licenses/by/4.0/legalcode). This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Juvenile fish survival is often strongly density dependent and results in relatively consistent average recruitment over a wide range of spawning stock biomasses. Hatching date-dependent mortality can limit contributions of individual hatching sub-cohorts (i.e., fish hatched in one period relative to another within the overall hatching distribution) to the year class and influence the potential for compensatory survival. We used trophic-based ecosystem models to evaluate effects of hatching date- dependent survival on the potential for compensation and regulation of year class strength and adult biomass by simulating variable early-life mortality. We built one model using data for north Florida lakes to represent a contracted spawning distribution and one model for south Florida lakes to represent a protracted spawning distribution using data for largemouth bass Micropterus salmoides with hatching-date dependent survival. Hatching datedependent survival strongly influenced contributions of individual hatching sub-cohorts to year classes (up to 70+% change in sub-cohort biomass), but total effects on year class strength and adult biomass were small (range -9% to +13% total biomass change). Total survival to age-1 was largely regulated by predation such that increases in individual subcohort survival did not result in large increases in total recruitment. Ecosystem models indicated that spawning distributions affected sub-cohort interactions to influence compensation and regulation, which had implications for understanding adult spawning periodicity and fisheries management.