Patterns of larval fish abundance in a bottomland hardwood wetland

Abstract

Larval fishes were collected with light traps and iehthyoplankton nets for two consecutive years during spring and early summer in the channel and floodplain (tupelo and oak forest) of the Cache River, Arkansas. A total of 8,113 individuals were collected between the greas. Twenty-eight species were confirmed, but total number of taxa, including genus and family level groupings, was 35. Pirate perch (Aphredoderus sayanus) was the most abundant species, with 21% of the total catch consisting of this fish. Percidae (darters) was the dominant family, comprising at least seven species and accounting for 57% of the total numbers of fish collected. The families Cyprinidae and Centrarchidae were also common. Specimens that could not be identified to species made up nearly 56% of the eatch. Species richness was similar among the three habitats probably due to hydraulic mixing, but individuals in the families Centrarchidae, Cyprinidae, and Percidae were more abundant in tupelo and oak habitats than in channel for net and light trap catches. Mean catch of total individuals in nets and light traps was greater in floodplain habitats than in the channel, particularly during spring 1989. Large catches in spring 1989 corresponded to higher water levels that expanded the aquatic/oak forest transition zone compared to lower water levels in 1988. Thus, late winter and spring floods that inundate the oak forest appear to be a major factor in regulating abundance of larval fishes in this bottomland hardwood wetland.