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Differences in lateral line morphology between hatchery- and wild-origin steelhead
Andrew D Brown1, Joseph A Sisneros, Tyler Jurasin
1Department of Speech & Hearing Sciences, University of Washington, Seattle, WA, USA.
Plos One
|April 5, 2013
Summary
Hatchery steelhead (Oncorhynchus mykiss) juveniles show morphological defects in mechanosensory systems. These differences predict reduced survival compared to wild juveniles due to impaired sensory function.
Area of Science:
- Aquatic Ecology
- Fish Biology
- Conservation Science
Background:
- Salmonid survival-to-adulthood shows disparities between hatchery and wild juveniles.
- Hatchery practices may impact juvenile development and subsequent survival rates.
Purpose of the Study:
- To investigate if hatchery-reared steelhead juveniles possess morphological defects in mechanosensory systems.
- To compare the lateral line structure, otolith composition, and brain weight of hatchery and wild steelhead juveniles.
Main Methods:
- Collected juvenile steelhead (Oncorhynchus mykiss) from two hatcheries and wild populations.
- Analyzed lateral line neuromast density, otolith mineralogy (aragonite vs. vaterite), and brain weight.
Main Results:
- Wild juveniles had more superficial lateral line neuromasts than hatchery juveniles.
- Hatchery juveniles showed a higher proportion of vaterite otoliths, while wild juveniles had aragonite otoliths.
- Wild juveniles exhibited significantly larger brain weights compared to hatchery juveniles.
Conclusions:
- Morphological differences in mechanosensory systems suggest reduced sensitivity to hydrodynamic and acoustic signals in hatchery steelhead.
- These defects may contribute to lower survival fitness in hatchery-reared steelhead post-release.
- Further physiological and behavioral studies are needed to confirm functional significance.
