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Morphological features to distinguish the larval stage of invasive Ruffe from native fish species
Citation:
Peterson, Greg, J. Lietz, J. Hoffman, AND E. Pilgrim. Morphological features to distinguish the larval stage of invasive Ruffe from native fish species. IAGLR Conference, Burlington, VT, May 25 - 29, 2015.
Impact/Purpose:
not applicable
Description:
Larval fish surveys are used in a variety of research and monitoring activities, including identification of nursery habitat and invasive species early detection. Morphologically-based taxonomic identification of larvae collected from these surveys, however, is often challenging. Current keys for Great lakes basin larval fishes are limited for many species, often lacking descriptions for certain developmental stages. Families such as Cyprinidae, Percidae and Centrarchidae present particular challenges for species-level identification. In our surveys, we had difficulty correctly identifying Ruffe, (Gymnocephalus cernuus), a recently-introduced species in the family Percidae. Ruffe is not included in the existing Great Lakes larval fish key and is inconsistently described in the scientific literature. Using DNA-based taxonomic identification we discovered and verified erroneous descriptions of larval Ruffe that may have led to misidentification by confusing it with native species. Here, we describe key morphological diagnostics for larval Ruffe identification, as well as morphologically similar and potentially confusing native species of the families Percidae and Centrarchidae. This is the first study to provide such diagnostics, and thus aids correct morphologically-based identification of Great Lakes fish larvae.