Date of Award
Master of Science
Natural Resource Ecology and Management
Joseph E Morris
Over the last century, there has been a shift in the United States population towards a more urbanized environment, with the vast majority of Americans (~80%) now living in urban areas. This has caused an alteration in recreational interests, as participation rates associated with traditionally rural activities (i.e., recreational angling), have steadily declined. Increased urban development and decreased angler participation have persuaded fishery managers that efforts to recruit and retain community (i.e., urban) anglers was necessary in contemporary fisheries management. However, distinct biotic and abiotic characteristics and diverse angler preferences and motivations in community fisheries make traditional fisheries management approaches frequently inadequate to meet management goals. Although introductions of novel species in community fisheries are often encouraged to meet diverse angler desires, investigations of their populations to assess viability in this environment are limited. For instance, Yellow Perch Perca flavescens is a popular sport and food fish across its range and investigations into its survival and reproduction are extensive. However, this research has been predominately conducted on natural lakes, rivers, and reservoirs, and little is known about populations in community fisheries, although this information is essential for effective management. Therefore, the overarching goal of the research was to assess whether Yellow Perch is a viable stocking option in central Iowa’s community ponds. The specific objectives of this research project included: (1) evaluate factors that influence Yellow Perch exploitation and survival in central Iowa’s community ponds, (2) evaluate factors that influence Yellow Perch reproduction and recruitment in central Iowa’s community ponds, and (3) to investigate the importance of coarse woody habitat complexity on Yellow Perch skein deposition and survival. My first chapter involved two years of fishery dependent (angler tag reporting) and independent (capture-recapture) data to estimate post-stocking angler exploitation and survival of adult Yellow Perch in community fishing ponds using a joint live-recapture and dead-recovery model. Angler tag returns indicated that the majority of captured fish were harvested (66%) and were female (71%). Logistic regression analysis suggested that increased Yellow Perch size (TL) was important to an angler’s decision to harvest. Seasonal exploitation ranged from 0-37% and was more prevalent in cold water seasons. The most supported model indicated that Yellow Perch survival was negatively related to harvest (β = -0.14; 95% CI = -0.17 to -0.10) and a quadratic effect of water temperature (β = 0.28; 95% CI = 0.02 to 0.53). Cumulative survival ranged from 0.22-0.92, and only one of the four ponds received considerable exploitation and subsequent low survival. This suggests stocking location and past angler experiences may be important indicators of potential harvest. The second chapter evaluated use of habitat additions as a spawning surface, two years of Yellow Perch early life history (i.e., egg, larvae, and juvenile) data, and angler exploitation to evaluate factors influencing reproduction and recruitment of Yellow Perch. A priori generalized linear model combinations consisted of biotic (habitat availability, juvenile Largemouth Bass abundance, adult largemouth Bass abundance, Yellow Perch stock size) and abiotic (water temperature) explanatory variables. We also used yield-per-recruit modeling in FAMS (Fishery Analysis and Modeling Simulator) to simulate the influence of community angler exploitation and three minimum length limits (150, 202, and 254 mm) on yield, spawning potential ratio, and mean size at harvest of stocked Yellow Perch. Yellow Perch deposited more skeins on introduced cedar trees than all other available habitats. Larval Yellow Perch density was positively related with mean monthly water temperature whereas juvenile Yellow Perch abundance was negatively related with juvenile Largemouth Bass abundance. Simulation modeling indicated that increased angler harvest with no minimum length limit may be contributing to growth and recruitment overfishing, but these relationships diminished with minimum length limits of 202 or 254-mm. Chapter 3 evaluated the effects of tree complexity on Yellow Perch skein deposition and survival using a nest survival model. We introduced 30 cedar trees that were manipulated to five complexities and conducted snorkeling surveys every two days where number and viability of skeins was recorded. Yellow Perch preferred to deposit skeins on more complex trees while deposition on low complexity trees was random. Nest survival models estimated that skeins deposited on the highest and lowest tree complexities had lower survival than skeins deposited on intermediate tree complexities. Collectively, our results indicate that increased exploitation can remove ~80% of a stocked adult Yellow Perch population in a community pond within two years; however, without exorbitant angler harvest survival was high. Additionally, the increased exploitation may have been due to angler familiarity and available amenities in one pond, suggesting site selection for novel stockings in community ponds is important. An abundant juvenile Largemouth Bass population may apply excessive predation pressure on young-of-the-year Yellow Perch causing recruitment to the juvenile stage to be completely lost. Increased exploitation may also have ramifications on successful reproduction and recruitment, as evidence of growth and recruitment overfishing suggests that the heavily exploited populations may not be sustainable unless harvest regulations such as minimum length limits are established. Finally, Yellow Perch prefer to deposit skeins on introduced trees in community ponds, and the intermediate complexities are optimal for skein survival. We recommend periodically replacing habitat as it decomposes past the intermediate complexity in an attempt to maximize Yellow Perch reproductive success.
Stephen John Grausgruber
Grausgruber, Stephen John, "Factors that influence Yellow Perch survival and reproduction in Iowa’s community ponds" (2021). Graduate Theses and Dissertations. 18500.