Understanding the relationship between anglers and fish is important to the management of angling fisheries. We compared angler catch rates estimated from creel surveys with (1) population density estimates of age-3 and older walleyes Sander vitreus based on mark-recapture and (2) mean growth of walleyes aged 4-6 in Oneida Lake during 1957-1959, 1997, and 2002-2003. We also compared walleye catchability to walleye population density. Angler catch rates were not related to walleye population density; however, by combining population density and walleye growth, we were able to explain 97% of the variability in angler catch rates, perhaps because growth rates were related to prey abundance. Catchability of walleyes decreased as population density increased. Consideration of these effects should improve our understanding of angler-fish dynamics and allow fishery managers to better predict the effects of management actions.

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Angler catch rates have been used to compare angler success in sport fisheries among years or systems, to assess relative fish abundance, and to evaluate management efforts. Understanding the factors that influence angler catch rates is critical for the proper interpretation and application of these data. Information for 10,998 angler trips was collected through an angler diary program conducted during 1994-1998 and direct-contact roving creel surveys conducted during 1997 and 2002-2004 to examine the influences of angler party size and trip length on the catch rates for walleye Sander vitreus, smallmouth bass Micropterus dolomieu, and yellow perch Perca flavescens at Oneida Lake, New York. Party size and trip length were correlated; therefore, we constructed separate models combining data for year, party size, and trip length to examine the relationship between these factors and the angler catch rate. In both the diary program and the creel survey, the angler catch rates for all species decreased significantly as the party size increased. For diary program data only, trip length also was negatively related to the angler catch rate, but party size typically accounted for more of the variation in angler catch rates than did trip length. Our results indicate that when party size or trip length varies among systems or years, failure to account for these factors may hinder the ability to accurately measure and compare angler catch rates. In addition, angler catch rates calculated with data from roving interviews (incomplete trips) may be biased because of party size. Catch data should be collected from each angler individually for parties consisting of more than one angler.

We compared one established population (Cayuta Lake) and one expanding population (Canadarago Lake) of landlocked alewives Alosa pseudoharengus to evaluate compensatory responses of alewives to predation by walleyes Sander vitreus. Alewives have been present in Cayuta Lake since at least 1977, and during the years 1995 to 2009 the population ranged from 24,470 fish/ha in 2000 to 3,800 fish/ha in 2007. Alewives were first observed in Canadarago Lake during 1999, and the population remained at low densities (<26 fish/ha) until reaching 370 fish/ha in 2006 and 1,050 fish/ha in 2009. Differences in zooplankton reflected higher planktivory rates in Cayuta Lake than in Canadarago Lake. Density of age‐3 and older walleyes was higher in Canadarago Lake (21–24 fish/ha) than in Cayuta Lake (12–14 fish/ha), despite elevated stocking rates of fingerling walleyes in Cayuta Lake during 2002–2006. Alewife density explained 77–84% of the variation in alewife length at age and 48–84% of the variation in condition (ages 0, 1, and 2) among years and lakes. Alewife length at age under low densities in Canadarago Lake was similar to observations in anadromous populations. Alewife recruitment (number of fall age‐0 recruits/spawner) was higher in Canadarago Lake than in Cayuta Lake. The combined data yielded a Beverton–Holt stock–recruitment curve that rose rapidly at low alewife densities, and 50% of the maximum recruitment was predicted to occur at 400 spawners/ha. Compensatory responses of alewives at low densities include decreased cannibalism and increased growth rates of both adults and age‐0 fish. Compensatory responses should be considered when evaluating the piscivore levels needed to control alewife populations or, conversely, when evaluating the risk of alewife population collapse in response to increased predation rates. Although alewife abundance declined in response to the experimental walleye stocking in Cayuta Lake, we were unable to increase the walleye population sufficiently to decrease alewife recruitment.