Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub

    Description

    Fish maturity status, sex ratio, and age and size at first maturity are important parameters in population assessments and life history studies. In most empirical studies of these variables, fish are sacrificed and dissected to obtain data. However, maturity status and the sex of mature individuals can be determined by inserting an endoscope through a small incision in the body cavity wall and viewing the gonads. The objective of this study was to evaluate endoscopy in a field setting for gonadal assessment of stream-resident forms of salmonids that mature at small sizes. Ninety-one brook trout Salvelinus fontinalis (60­210 mm fork length [FL]) were obtained via electrofishing and anesthetized. Maturity status and sex of mature individuals were determined with an endoscope. After recovery, individuals were euthanized with anesthetic and were dissected to validate the endoscopic classification. Endoscopy correctly determined the maturity status and sex of mature individuals for 96% of the brook trout; the highest accuracy was observed for the smallest (60­70 mm FL) and largest (.140 mm FL) individuals examined. In the misclassifications, visceral fat hampered visibility and was mistaken for mature testes. Immediate post-procedure mortality was 3.3% and was limited to individuals smaller than 70 mm FL. Endoscopy is a useful technique that can be used in field settings to assess maturity status and sex of mature fish with a low rate of immediate mortality.

    Publication Notes

    • You may send email to rmrspubrequest@fs.fed.us to request a hard copy of this publication.
    • (Please specify exactly which publication you are requesting and your mailing address.)
    • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.

    Citation

    Swenson, Erica A.; Rosenberger, Amanda E.; Howell, Philip J. 2007. Validation of endoscopy for determination of maturity in small salmonids and sex of mature individuals. Transactions of the American Fisheries Society. 136: 994-998.

    Keywords

    endoscopy, maturity, salmonids, fish

    Related Search


    XML: View XML
Show More
Show Fewer
Jump to Top of Page
https://www.fs.usda.gov/treesearch/pubs/31520