ANALYSES FOR DIFFERENTIATING LITTORAL FISH ASSEMBLAGES WITH CATCH DATA FROM MULTIPLE SAMPLING GEARS

We evaluated analytical approaches to discriminating littoral fish assemblages with catch data from multiple sampling gears. Eight littoral sites were sampled with seines, fyke nets, and gill nets in Lake Mendota, Wisconsin, in summer 1990. No one gear sampled the full composition represented by the total catch. Fyke nets best discerned differences among littoral fish assemblages. Young-of-year (age-0) bluegills Lepomis macrochirus and age-0 black crappies Pomoxis nigromaculatus caught in the fyke nets were the strongest discriminators among sites. Gill nets did not differentiate among sites. With the seine and fyke net, analysis of absolute abundance data detected differences among sites; analysis of presence-absence and rank abundance data did not. Fish caught in fyke nets were the most frequent significant correlates in site ordinations based on log-abundance data for taxa, defined as a combination of species, age (age 0 or adult) and gear type. Retention of gear designation in site ordination attributes facilitated the assessment of gears for differentiating littoral fish assemblages.