Diet of Adult Olympic Mudminnow,Novumbra hubbsi

Abstract

Abstract Olympic mudminnow (Novumbra hubbsi) is a small species endemic to western Washington State that inhabits marshy, wetland-type areas with abundant aquatic macrophytes. Because they can be locally abundant and may be the only fish species present, they may have important effects on the aquatic community. However, little is known about their diet under natural conditions. To get a detailed account of their feeding ecology, Olympic mudminnow were sampled from six sites. Three sites were sampled monthly from February to August 2012 and the other three sites were sampled once in June 2012. Gastric lavage was used to collect stomach samples from fish ≥ 40 mm total length (TL). Stomach samples were collected from 477 fish (40–75 mm TL). Olympic mudminnow diet was comprised primarily of aquatic invertebrates. By weight, oligochaetes and chironomid larvae were the predominant prey types but by number, copepods were the predominant prey type. Of the three monthly sample sites, diet overlap between seasons w...