Record Details
Early self-sorting behavior in Chinook salmon is correlated with variation in growth, behavior and morphology later in life.
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Early self-sorting behavior in Chinook salmon is correlated with variation in growth, behavior and morphology later in life. |
| Names |
Unrein, Julia R.
(creator) Schreck, Carl B. (advisor) |
| Date Issued | 2014-12-10 (iso8601) |
| Note | Graduation date: 2015 |
| Abstract | Juvenile Chinook salmon (Oncorhynchus tshawytscha) exhibit an array of life history tactics in Oregon's Willamette River Basin, yet we do not know to what extent it is driven by phenotypic plasticity or whether it is predetermined and how conditions in the early rearing environment may affect phenotype expression. We have found hatchery-origin fry sort themselves into distinct surface and bottom oriented phenotypes within days of first feeding and this orientation persists after separation. Surface and bottom phenotypes demonstrated differences in head and body morphology at 2 months post-swim up across three brood years (BY). The surface phenotype exhibits a shorter head and deeper body compared to bottom phenotype. The BY 2012 surface phenotype spent 3 times longer, on average, interacting with their mirror image in an open arena than the bottom phenotype. Tests conducted with BY 2013 fish indicated that bottom-oriented fish engaged in swimming-against-mirror behavior 5 times more than the surface phenotype when the mirror was near gravel refuge. After 8 months of rearing, the BY 2012 surface phenotype was 10% larger than bottom fish and morphometric differences persisted. Surface and bottom phenotypes from BY 2013, were reared under two temperatures and as either separate or combined phenotype groups. The two phenotypes grew at the same rate at 12°C, irrespective of separate or combined rearing, but at 7°C surface fish were significantly larger than bottom fish after three months until temperatures increased after which the two phenotypes converged. While equal in size, the morphologies of the BY 2013 orientation phenotypes were consistent with previous findings. These differences seen in body shape between the surface and bottom oriented groups are similar to differences exhibited between wild subyearling and yearling life history types in the basin. Such phenotypic differences may offer potential for predicting juvenile life history trajectory early in life. |
| Genre | Thesis/Dissertation |
| Topic | Chinook salmon -- Vertical distribution -- Oregon -- Willamette River Watershed |
| Identifier | http://hdl.handle.net/1957/54856 |
