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

• Published in: Ecology and evolution 2022-12, Vol.12 (12), p.e9679-n/a
• Main Authors: Skoglund, Stefan, Whitlock, Rebecca, Petersson, Erik, Palm, Stefan, Leonardsson, Kjell
• Format: Article
• Language: English
• Subjects: Behavior; behavior biology; Bias; Ecological effects; Ecology; Ekologi; Error analysis; Estimates; Fish; Fisheries; fisheries management; Habitat selection; Habitats; Parameters; Population density; population ecology; population productivity; Productivity; Recruitment; Spawning; stock‐recruitment
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.9679

The relationship between the spawning stock size and subsequent number of recruits is a central concept in fisheries ecology. The influence of habitat selection of spawning individuals on the stock‐recruitment relationship is poorly known. Here we explore how each of four different spawner behaviors might influence the stock‐recruitment relationship and estimates of its parameters in the two most commonly used stock‐recruitment functions (Beverton‐Holt and Ricker). Using simulated stock‐recruitment data generated by four different spawner behaviors applied to multiple discrete habitats, we show that when spawners were distributed proportionally to local carrying capacities, there was small or no bias in estimated recruitment and stock‐recruitment parameters. For an ideal free distribution of spawners, larger bias in the estimates of recruitment and stock‐recruitment parameters was obtained, whereas a random and a stepwise spawner behavior introduced the largest bias. Using stock‐recruitment data corresponding to a “realistic” range of population densities and adding measurement error (20%–60%) to the simulated stock‐recruitment data generated larger variation in the estimation bias than what was introduced by the spawner behavior. Thus, for exploited stocks at low population density and where spawning stock size and recruitment cannot be observed perfectly, partial observation of the possible spawner abundance range and measurement error might be of higher concern for management. Total female abundance compared with the number of females at five local spawning sites with a common environment (environment 1). Panels represents combinations of the four spawner behaviors (rows) and two SR relationship (columns). Note that the two axes are shown on logarithmic scales.