Twenty species of freshwater fishes were collected from Minnesota, Iowa and Michigan and their whole-body carbon, nitrogen and phosphorus contents and the respective C:N:P ratios were determined. Patterns were examined in intra-and interspecific variation, allometry and variation caused by habitat and trophic level in whole fish while controlling for the role of phylogeny. Stoichiometric variation was greater across than within species, C:N:P allometry was speciesspecific, nutrient content within a species was somewhat habitat-specific and P concentration showed a strong phylogenetic signal. Stoichiometric relationships with allometry and feeding guild were observed but were not significant in an analysis accounting for non-independence of closely related species. Supportive evidence for the hypothesis that the considerable variation in whole fish phosphorus concentrations could be ascribed to differences in bone and scale development, as previously suggested, is shown. Whole fish Ca:P ratios had a nearly constant stoichiometry consistent with the chemical signature of bone. This result combined with a phylogenetic signal for fish P indicated that the great stoichiometric variability among fish taxa in P content was derived almost entirely from skeletal investment.

Wetland restoration is expected to reduce external phosphorous (P) loading to hypereutrophic Upper Klamath Lake in Oregon, USA, where P was identified as the primary driver of lake productivity. However, previous laboratory experiments showed that a large P release could occur when former agricultural land is re-flooded for restoration, thus presenting an initial challenge for wetland restoration projects. We tested whether results from those experiments were supported during the initial phase of restoration at the Williamson River Delta adjacent to Upper Klamath Lake. Our objectives were to document post-flood surface water nutrient concentrations, estimate the P mass released from the newly flooded wetlands, and compare these results to the laboratory experiments. Phosphorus concentrations in the wetlands ranged from 0.1 to 0.63 mg P/L and were up to six times greater than in the lakes, corroborating that the wetlands released P upon flooding. However, we estimated 2 Mg P released within three weeks of flooding, which is much lower than the anticipated 64-Mg release from these wetlands, and a fraction of the annual 21-25 Mg load from the Delta before reconnection. This pulse is expected to be short-term; longer term studies will address the role of these wetlands in retaining nutrients.

We examined habitat use by age‐0 Lost River suckers Deltistes luxatus and shortnose suckers Chasmistes brevirostris over six substrate classes and in vegetated and nonvegetated areas of Upper Klamath Lake, Oregon. We used a patch occupancy approach to model the effect of physical habitat and water quality conditions on habitat use. Our models accounted for potential inconsistencies in detection probability among sites and sampling occasions as a result of differences in fishing gear types and techniques, habitat characteristics, and age‐0 fish size and abundance. Detection probability was greatest during mid‐ to late summer, when water temperatures were highest and age‐0 suckers were the largest. The proportion of sites used by age‐0 suckers was inversely related to depth (range = 0.4‐3.0 m), particularly during late summer. Age‐0 suckers were more likely to use habitats containing small substrate (<64 mm) than those containing large substrate (>64 mm) and habitats with vegetation than those without vegetation. Relatively narrow ranges in dissolved oxygen, temperature, and pH prevented us from detecting effects of these water quality features on age‐0 sucker nearshore habitat use.

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