Description and identification of larval fishes in Alaskan freshwaters

Abstract

Identification of larval fish is important for assessing fish populations and human impact on fish ecosystems but is difficult due to subtle differences between larvae of different species. A key to larval fishes is valuable for successful population studies. This thesis is a preliminary study towards the development of a key to the larval stages of Alaskan freshwater fishes. Early life history information on 23 of approximately 40 Alaskan freshwater species was obtained from the literature. Six of these species (sheefish, Stenodus leucichthys; Arctic grayling, Thymallus arcticus; Arctic char, Salvelinus alpinus; Dolly Varden, S. malma; longnose sucker, Catostomus catostomus; and slimy sculpin, Cottus coqnatus) were laboratory-reared or collected near Fairbanks for additional information. Technical illustrations and morphometric data were prepared for each of the six species. This study indicates that follow-up research on several whitefishes will be critical for developing a comprehensive larval fish key to Alaskan freshwater species.