Degree-day accumulation influences annual variability in growth of age-0 walleye

Abstract

a b s t r a c tThe growth of age-0 fishes influences survival, especially in temperate regions where size-dependent over-winter mortality can be substantial. Additional benefits of earlier maturation and greater fecundity may exist for faster growing individuals. This study correlated prey densities, growing-degree days, water-surface elevation, turbidity, and chlorophyll a with age-0 walleye Sander vitreus growth in a southcentral Nebraska irrigation reservoir. Growth of age-0 walleye was variable between 2003 and 2011, with mean lengths ranging from 128 to 231 mm by fall (September 30th-October 15th). A set of a priori candidate models were used to assess the relative support of explanatory variables using Akaike's information criterion (AIC). A temperature model using the growing degree-days metric was the best supported model, describing 65% of the variability in annual mean lengths of age-0 walleye. The second and third best supported models included the variables chlorophyll a (r 2 = 0.49) and larval freshwater drum density (r 2 = 0.45), respectively. There have been mixed results concerning the importance of temperature effects on growth of age-0 walleye. This study supports the hypothesis that temperature is the most important predictor of age-0 walleye growth near the southwestern limits of its natural range.

Factors influencing recruitment of walleye and white bass to three distinct early ontogenetic stages

“…; Uphoff et al. ; Kaemingk et al. ); these factors are more identifiable if fish abundances are monitored during each of the early ontogenetic stages from hatch to recruitment (Forney ; Hoxmeier et al.…”

“…Age‐0 walleye growth (and presumably survival) was positively affected by the number of growing‐degree days in a nearby reservoir (Uphoff et al. ). The negative relationship between spring warming rate and age‐0 larval white bass abundance was unexpected, given that growth of white bass has been positively correlated to water temperature (Ruelle ) or air temperature (Pope et al.…”

“…Our models explained 40%-80% (68 AE 9%; mean AE SE) and 71%-97% (81 AE 6%) of the variability in catch for walleye and white bass respectively; this compares favourably with other models describing year-class strength of walleye (31%, Quist et al 2003;57%-97%, Hoxmeier et al 2004;66%-69%, DeBoer et al 2013) and white bass (31%-36%, DeBoer et al 2013) in multiple water bodies. Environmental factors often explain much of the variation in year-class strength observed in fish populations (Boehlert & Mundy 1988;Hansen et al 1998;Daskalov 1999;DeBoer et al 2013;Uphoff et al 2013;Kaemingk et al 2014a); these factors are more identifiable if fish abundances are monitored during each of the early ontogenetic stages from hatch to recruitment (Forney 1976;Hoxmeier et al 2006), as survival gradually increases through early ontogenetic stages (Houde 2002).…”

“…Additionally, fish grow faster when enzymatic and metabolic activity increases with temperature (Higley et al 1986;Clarke & Johnston 1999), and there is a high correlation between growth and survival for age-0 fish (reviewed by Sogard 1997). Age-0 walleye growth (and presumably survival) was positively affected by the number of growing-degree days in a nearby reservoir (Uphoff et al 2013). The negative relationship between spring warming rate and age-0 larval white bass abundance was unexpected, given that growth of white bass has been positively correlated to water temperature (Ruelle 1971) or air temperature (Pope et al 1997;Phelps et al 2011).…”

“…First-year survival, and therefore year-class strength (i.e. the relative number of individuals in a cohort), of fish is often less consistent in dynamic and unpredictable environments because abiotic and biotic environmental factors can interact to affect year-class strength of fish (Boehlert & Mundy 1988;Hansen et al 1998;Daskalov 1999;DeBoer et al 2013;Uphoff et al 2013;Kaemingk et al 2014b). For a particular cohort, environmental regulation of year-class strength likely begins before that cohort even hatches; environmental factors can affect parental fish condition and thus reproductive investment by adult fish (Baltz & Moyle 1982;Johnston & Leggett 2002;DeBoer et al 2015).…”