Pacific Salmon Prespawn Mortality: Patterns, Methods, and Study Design Considerations

cohosalmon

By Tracy Bowerman, Matthew L. Keefer, and Christopher C. Caudill

Adult Pacific salmon Oncorhynchus spp. may reach spawning grounds but perish before reproducing, a phenomenon known as “prespawn mortality” (PSM).

This review synthesizes information on PSM rates and estimation methods to evaluate patterns and facilitate study design development.  

Questionnaire responses from 60 fisheries professionals indicated that female PSM was routinely monitored in numerous Pacific salmon populations, but variations in data collection and reporting could lead to systematic biases in estimates. Reported PSM rates varied among years and locations, ranging from 0% to over 90%. An evaluation of methodological variations within a single data set illustrated that PSM estimates were sensitive to estimation method, the timing and spatial extent of sampling, and inclusion of male data. To improve accuracy of PSM estimates based on carcass data, we recommend frequent surveys during holding and spawning periods, use of spatially and temporally balanced study designs with adequate sample sizes, and separate reporting for males and females.

Members click below for the December 2016 Fisheries magazine's complete issue. Non-members, join here.

This content is for members only. Please login.

Unfortunately there is lot of unexpected situation which force patients to take medications. Online drugstores provides best-quality prescription medications and other medications. Cialis is a physic prescribed to treat sundry complaints. What do you think about http://isviagraoverthecounter.com/over-the-counter-anti-inflammatory.html? As sure as a gun, there are many aspects you have to think about this. Cialis is the best treatment for helping men to sustain an hard-on. What do you already know about Over the Counter Anti Inflammatory? Of all the things in the field of healthcare that pique our attention most, it's sexual heartiness, especially buying an over the counter anti-inflammatory pill. Because some of these conditions are medical emergencies, it's great to know the symptoms. Mercifully, most cases of erectile disfunction are treatable, so it is considerable to share your concerns with your partner and physician.