From spawner habitat selection to stock-recruitment: Implications for assessment

Area of Science:

• Fisheries Ecology
• Population Dynamics
• Ecological Modeling

Background:

• The stock-recruitment relationship is fundamental to fisheries ecology.
• The effect of spawner habitat selection on this relationship is not well understood.

Purpose of the Study:

• To investigate how four distinct spawner behaviors influence stock-recruitment relationships.
• To assess the impact of these behaviors on parameter estimates for Beverton-Holt and Ricker models.

Main Methods:

• Simulated stock-recruitment data across multiple habitats.
• Incorporated four spawner behaviors: proportional, ideal free, random, and stepwise.
• Applied Beverton-Holt and Ricker stock-recruitment functions.

Main Results:

• Proportional spawner distribution resulted in minimal bias in recruitment and parameter estimates.
• Ideal free distribution led to larger bias, with random and stepwise behaviors causing the most significant bias.
• Measurement error (20%-60%) and population density introduced more variability in bias than spawner behavior alone.

Conclusions:

• Spawner behavior influences stock-recruitment dynamics and model parameterization.
• For exploited stocks with imperfect observation, measurement error and limited spawner abundance data are critical management concerns.