Growth, condition, diet, and consumption rates of northern pike in three Arizona reservoirs

Inferring occurrence of growth checks in pike (Esox lucius) scales by using sequential isotopic analysis of otoliths

“…Corroborative methods, as presented in this paper, or direct validations based on length distributions of juveniles or on the recapture of individually marked pike on a subsample before studying a population age structure, are necessary when scales are used to determine the ages of fish. Variability in growth exists among Lake Annecy fish of similar size as was shown by Flinders and Bonar for pike populations from different origins. Pike caught in February with a TL ranging 510 to 570 mm are 2 years old while pike caught later during the year (June) with a TL of 600 mm are from the previous cohort.…”

An experimental approach to determine esocid prey preference in replicated pond systems

“…Throughout the United States, millions of rainbow trout are stocked annually as sport fish in put-and-take fisheries; however, we have known for more than 50 years that stocked rainbow trout are highly susceptible to predation (Johnson and Hasler 1954), and more recently they have been shown to end up as the primary forage base for piscivores (Marwitz and Hubert 1997, Yule et al 2000, Flinders and Bonar 2008. Additionally, elevated body condition of top predators is correlated with the stocking of rainbow trout (Marwitz andHubert 1997, Flinders andBonar 2008), and exceptional growth rates of top predators have been related to the availability of soft-rayed prey fishes with high energy density and minimal handling time, such as rainbow trout (Beyerle 1971, Johnson andMartinez 2000). These findings suggest that apex predators (including esocids) are taking advantage of energy subsidies in the form of stocked rainbow trout.…”

Tiger muskellunge predation on stocked salmonids intended for recreational fisheries

“…Esocids (Marwitz and Hubert 1997, Flinders and Bonar 2008, Lepak et al 2012a, 2012c and other piscivores like walleye (Sander vitreus; Yule et al 2000, Baldwin et al 2003, Lepak et al 2012b) are consuming stocked fish, which is expected given that hatchery-reared fish have relatively limited experience with predators (Suboski and Temple ton 1989, Brown and Smith 1998, Ferrari et al 2010). …”

“…Specifically, northern pike have been shown to prefer to consume rainbow trout over white suckers when both were available in small, artificial pond systems (Lepak et al 2012a). Additionally, elevated growth rates and body condition in top predators have been correlated with stocking of soft-rayed prey fish (salmonids) with high energy density and minimal handling time (Marwitz and Hubert 1997, Johnson and Martinez 2000, Flinders and Bonar 2008. These findings suggest that apex predators are taking advantage of energy subsidies in the form of stocked fish.…”

“…Although esocid dietary habits (northern pike primarily) have been evaluated previously in small experimental systems or inferred from diet data with limited temporal scale (e.g., Flinders andBonar 2008, Lepak et al 2012a), tiger muskellunge diets specifically have not been evaluated across multiple (5) reservoirs using stable isotope analysis. This technique is beneficial because isotopic signatures used to characterize diets of large piscivores are integrated across time, and the mixing model is able to account for variability in isotopic signatures of prey sources.…”