Epibenthic fishes and decapod crustaceans in northern estuaries: A comparison of vegetated and unvegetated habitats in maine

Abstract

Species richness and abundance of epibenthic fishes and decapod crustaceans were quantified with day- time beam trawl tows and throw traps to provide information on nekton assemblages in Zostera marina and unvegetated sandy habitats in northern latitudes. Sampling at randomly selected stations with a 1.0-m beam trawl occurred in eelgrass (Zostera marina) and unvegetated sandy substrates of two mid-coastal Maine estuaries: Casco Bay and Weskeag River. Random 1.0-m throw trap samples were collected in Zostera and adjacent unvegetated sandy substrates in Casco Bay and Weskeag River as well. Species richness and faunal abundances were positively associated with the occurrence of Zostera within Weskeag River and Casco Bay estuaries using both gear types. A total of 17 species of fishes and 6 species of decapods were collected in the two estuaries using both gears. Populations of most species were dominated by young- of-the-year and juvenile life history stages. Number and densities of fishes were higher in Zostera, due primarily to the abundances of eelgrass residents such as threespine, Gasterosteus aculeatus, and fourspine sticklebacks, Apeltes quadracus, grubby, Myoxocephalus aenaeus, and cunner, Tautogolabrus adspersus. Crangon septemspinosa dominated decapod catch per unit effort and density in both estuaries and habitats.