Effects of source–sink dynamics on harvest policy performance for yellow perch in southern Lake Michigan

Reconciling stock assessment and management scales under conditions of spatially varying catch histories

“…Combining the areas, they found, often leads to either over-or underharvesting the resource. Wilberg et al (2008) also found that 'state-specific' harvest policies that explicitly consider subpopulation spatial dynamics outperformed those that ignored spatial complexity, even when the underlying population dynamics were uncertain. Punt et al (2000) illustrated how allowing for spatial structure in the stock assessment of Australian school shark (Galeorhinus galeus) decreased overall stock assessment uncertainty and uncovered a highly depleted population not recognized when all areas were combined into one assessment.…”

Evaluating alternative harvest policies for yellow perch in southern Lake Michigan

“…Adults are thought to generally remain within areas much smaller than those managed by each state, and thus most mixing of the population across management-area boundaries likely occurs during early life stages because larvae are pelagic and disperse via passive drift (Dettmers et al, 2005;Beletsky et al, 2007). As a result, mature yellow perch may be contributing to recruitment in areas other than where they reside (also see Wilberg et al, 2008). Indeed, there is substantial correlation in yellow perch recruitment among management areas (Wilberg, unpublished data), although this may also be influenced by regional-level drivers.…”

“…This possibility was not incorporated into the current analysis. However, Wilberg et al (2008) used the yellow perch simulation model described here to explore how sensitive our results are to such extreme cases of "source-sink" population dynamics. Data that better characterize the stock-recruitment relationship for yellow perch could be very informative (sensu Clemen and Reilly, 2001), especially if these data reduced the uncertainty attributed to mixing of recruits among management areas.…”

Dinámica metapoblacional, ocupación espacial y migración en bivalvos de importancia comercial: el caso de la almeja Tawera gayi (Bivalvia: Veneridae) en el Mar Interior de Chiloé

“…Por muchos años se consideró la existencia de estas dos estrategias por separado, y ante esto los esfuerzos del manejo pesquero se enfocaron en categorizar las poblaciones entre fuentes y sumideros, considerando incluso que al proteger la población fuente o madre, se aseguraba la sustentabilidad de la especie (Wilberg et al 2008). Sin embargo, teóricamente es posible que la alternancia de estos procesos sea más bien un efecto compensatorio sobre la probabilidad de ocupación del espacio por parte de las metapoblaciones (Thomas & Jones, 1994).…”