| Description |
This portion of the data release presents fish diet data from Chinook and coho salmon collected in the Elwha River estuary, Washington, in 2006, 2007, 2013, and 2014 (there are no associated USGS Field Activities numbers because data were collected predominantly by biologists from the Lower Elwha Klallam Tribe). Fish were collected using a beach seine at six locations throughout the estuary. Fish were transferred to buckets containing aerated ambient water and kept cool until handling. We anesthetized fish in a diluted solution of tricaine methanesulfonate (MS-222) to count, identify, and measure fork length (FL) to the nearest mm and weight to the nearest 0.1 g. After recovery from anesthesia, all fish were released at the point of capture. Stomach contents from a sub-sample of Chinook and coho were extracted via non-lethal gastric lavage and preserved in ethanol. When possible, stomach contents from ten individuals of each species between 55–199 mm fork length were collected at each site during each sampling event. Fish with no regurgitated prey were recorded as empty stomachs. Fish diet samples were sent to a professional taxonomist for processing and identification to the lowest practical taxonomic level. Aquatic taxa were typically identified to the genus or species level and terrestrial taxa to family or genus. Some less-common taxa or partially-digested prey items were identified to Order or Class. The locations of samples were determined with a hand-held global positioning system. Fish diet data are provided in a comma-delimited spreadsheet. [More]
|
