Juvenile steelhead Oncorhynchus mykiss enter the northern California Current ecosystem from the Columbia River and other Pacific Northwest coastal rivers and include several populations that are listed under the U.S. Endangered Species Act. However, relatively little is known about the response of these populations to interannual variability in ocean conditions… These findings highlight the potential for warm ocean years to influence the diet composition and morphology of Columbia River steelhead populations and may lead to a better understanding of factors influencing survival of juvenile steelhead during early marine residence…Read More

Photo Credit: NOAA Fisheries/Oregon State University

Climate change impacts to ocean ecosystems are altering the distribution and abundance of fish populations and impacting the people whose health, well‐being, and livelihoods depend on them. Thousands of published papers make it very clear that fish are on the move, alterations in productivity are occurring, and natural and human ecosystems are responding to climate variability and change…Read More

Photo Credit: NASA

Electrofishing studies in the 1990s established that higher frequencies of pulsed DC (e.g., 60 Hz) generally result in more spinal injury to fish in comparison with lower pulse frequencies (e.g., 30 Hz). In response to those findings, some agencies adopted low pulse frequency standards to minimize fish injury. However, those earlier studies did not assess whether capture efficiency (CE) was also influenced by pulse frequency. We sampled small trout streams (1–6‐m average width; SE = 0.14 m) by backpack electrofishing with settings of 30 and 60 Hz to evaluate the effect of pulse frequency on both CE and spinal injury rates for Cutthroat Trout Oncorhynchus clarkii , Rainbow Trout O. mykiss , and Brook Trout Salvelinus fontinalis…Read More

Photo Credit: Jim Reynolds

The Rainbow Trout Oncorhynchus mykiss is a salmonid fish that is maintained in aquaculture facilities and used as a source of protein around the world. Veterinarians need accurate, efficient tools and straightforward assessments to evaluate the health status of fish, like Rainbow Trout, that are cultivated on farms. In this study, two genetically distinct broodstock lines of Rainbow Trout originally obtained from two different U.S. states but propagated at Rushing Waters Trout Farm (Palmyra, Wisconsin) were evaluated. Groups originating from both states (State A: n = 20; State B: n = 20) were surveyed with a modified health assessment in a prospective, randomized, single‐blind study…Read More

Photo Credit: Dr. Michael Collins