Fish, instream habitat, and physical stream conditions were surveyed in 29 agricultural streams in the Red River of the North basin during summer 1994 and the Minnesota River basin during summer 1997. Our goal was to determine which instream habitat and physical conditions should be considered for stream restoration. Principle components analysis identified six axes that explained 79% of the total variability in instream habitat and physical conditions. Percent run, percent boulder, percent woody debris, percent overhanging vegetation, percent sand, and frequency of erosion were the variables best associated with these axes. Multiple linear regression analysis of the instream habitat and physical conditions explained 14–50% of the variability in fish community composition. Managers of agricultural warmwater streams in the northern Midwest should emphasize these six instream habitat and physical conditions, and the factors that influence them, during stream restoration.

Existing models of hooking mortality for walleyes Sander vitreus in large polymictic lakes are inadequate for estimating the number of catch‐and‐release mortalities in deeper, stratified lakes where fish are predominantly caught from depths greater than 10 m. To improve the understanding of how water depth affects catch‐and‐release mortality, logistic regression was used to investigate how depth of capture, fish length, and epilimnetic water temperature affect hooking mortality rates. In 2006 and 2007, 319 walleyes were caught by anglers at 5.8–17.1‐m depths during a total of 10 angling events (July–September) on Rainy Lake, Minnesota. Fish were released into holding cages that allowed them the opportunity to reestablish themselves at their depths of capture; survival was recorded after 5 d (2 d for one cage). After accounting for the effects of experimental handling time (i.e., the time between hook removal and fish placement in the holding cage), capture depth had the largest effect on mortality; increases in either factor were associated with higher mortality rates. A mixed‐effects model showed that pseudoreplication (i.e., correlations in survival rates among fish held in the same cage) did not detrimentally affect model parameter estimates or significance tests. In contrast to previous studies of hooking mortality in Minnesota, neither water temperature nor fish length best explained the mortality rates. By providing improvements over previous models, the logistic hooking mortality model developed in this study will allow managers to more effectively estimate hooking mortality rates in Rainy Lake and other deep lakes. Received February 11, 2011; accepted May 13, 2011

We examined differences in sex‐specific growth and weight–length relationships for five Minnesota populations of black crappies Pomoxis nigromaculatus. Male black crappies typically grew slightly faster than females, but observed differences in mean total lengths (TLs) at age were always 15 mm or less and were typically less than 10 mm. We detected few differences in log10(weight)–log10(TL) regressions between sexes, and predicted weights at 200 and 250 mm differed between sexes by less than 10 g. Our results indicate that biologists are justified in pooling sexes when estimating population metrics such as growth and condition because the minor differences in growth and weight–length relationships we observed would be unlikely to affect management decisions. Furthermore, while our evaluation did not specifically examine angler harvest selectivity, the small differences in growth and weight–length relationships observed between sexes seemed unlikely to promote sex‐selective angler harvest within the lakes we examined. However, it remains possible that male growth advantages of more than 10 mm may promote selective removal of male fish in black crappie fisheries regulated by minimum length limits, where anglers may use the minimum length limit as a target when selecting fish for harvest and are more likely to measure individual fish.

is an element of the comprehensive body of information developed as part of the NAWQA Program. The program depends heavily on the advice, cooperation, and information from many Federal, State, interstate, Tribal, and local agencies and the public. The assistance and suggestions of all are greatly appreciated.

This report is an element of the comprehensive body of information developed as part of the NAWQA Program. The program depends heavily on the advice, cooperation, and information from many Federal, State, interstate, Tribal, and local agencies and the public. The assistance and suggestions of all are greatly appreciated.