Genetic Diversity Among Walleye Sander Vitreus Populations In Inland Ontario

Author : Andrew Peter Bade
Publisher :
ISBN 13 :
Total Pages : 232 pages
Book Rating : 4.:/5 (131 download)

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Download or read book The Behavioral Ecology of Walleye (Sander Vitreus) written by Andrew Peter Bade and published by . This book was released on 2021 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many migratory animals time reproduction using environmental cues (e.g., photoperiod) that signal favorable conditions for offspring (e.g., food availability). However, environmental change can decouple these cues from the conditions relevant to offspring success. In turn, variation in reproductive behaviors may be critical to population persistence in a changing environment. For example, while natal homing can lead to valuable local adaptations in a stable environment, straying to new breeding sites can buffer against environmental change. Among exploited species, knowledge of reproductive behavior, such as spawn timing (phenology) and spawning site selection, has proven useful to fisheries management by influencing angling dynamics, estimates of biological reference points, and stock delineations. Thus, a well-developed understanding of reproductive phenology, breeding site selection, and fishery dynamics could help agencies effectively conserve and manage fisheries in ecosystems experiencing environmental change. Accordingly, my dissertation research sought to better understand the reproductive behaviors and angling dynamics of Lake Erie’s walleye population. In collaboration with other researchers and agency biologists, I used acoustic telemetry, creel surveys, environmental monitoring data, and quantitative techniques to discern the spawning behaviors and angling dynamics of this population. We assessed the timing of residency in spawning sites, focusing on how environmental cues and individual characteristics drive observed variation (Chapter 2), developed a quantitative framework to estimate the frequencies of each potential spawning site selection strategy (Chapter 3), demonstrated sex based-differences in spawning behavior and male-biased walleye harvest during the spawning season (Chapter 4), and modeled the impact of fishery characteristics and angler behaviors on recreational catch outcomes (Chapter 5). Each chapter generated new insights to the benefit of fisheries management through advances in our understanding of reproductive ecology and angling dynamics. In Chapter 2, we found that the timing of residency in spawning sites differed between sexes and among spawning locations and was controlled by photoperiod and temperature. The varying responses to warming suggest that reproductive resilience is promoted by conserving local spawning populations and a broad age structure. The findings from Chapter 3 demonstrated that, although spawning site fidelity and annual spawning are common, apparent skipped spawning also occurs (~ 14% of observations). Accounting for this potential skipped spawning led to revised biological reference points, owing to adjusted estimates of spawning stock biomass. Additionally, although few walleye strayed, the pattern of straying indicated that some stocks mix heavily. In Chapter 4, we found strong evidence for sex-specific spawning behaviors, with males occupying spawning grounds longer than females, which helped explain male-biased walleye harvest on the spawning grounds. Lastly, in Chapter 5, modeling creel survey data showed that angler decisions influenced catch outcomes more than abundance of the targeted walleye population. The findings from this chapter can help anglers maximize their probability of fishing success, given desired catch outcomes. The improved understanding of Lake Erie walleye reproductive behavior, angling dynamics, and the relationships between them, should help agencies worldwide keep their valued fish populations sustainable in the face of continued environmental change.