Record Details
Life-history strategies of rainbow trout (Oncorhynchus mykiss) across a volcanic disturbance gradient at Mount St. Helens, Washington
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Life-history strategies of rainbow trout (Oncorhynchus mykiss) across a volcanic disturbance gradient at Mount St. Helens, Washington |
| Names |
Blackman, Tara Elizabeth
(creator) Reeves, Gordon H. (advisor) |
| Date Issued | 2014-12-03 (iso8601) |
| Note | Graduation date: 2015 |
| Abstract | In this study, I examine the influence of habitat gradients created by the 1980 eruption of Mount St. Helens, Washington USA on a recently established Rainbow Trout (Oncorhynchus mykiss) population in the Spirit Lake basin. My goal was to evaluate the responses of fish in seven streams across a volcanic disturbance gradient that included three major zones: Pyroclastic Flow (PF), Debris Avalanche (DA), and Blowdown Forest (BD). I compared fish habitat association and demography, sex ratios among age classes, and odds ratios of maturation to determine life-history responses. Age-1 maturing males were the most common life-history observed for non-young-of-year males across all fish-bearing streams. The propensity toward an early-maturing strategy seems to be mediated by two factors: one, stream resources limit residency (no fish older than age-2) and two, a strong relationship between length and maturity. Sex ratios for age-1 fish ranged in proportion from 100% male-biased in one of three fish-bearing PF streams, 65% male-biased (though not statistically different from 1:1) in one of two DA streams, to a roughly 1:1 ratio in all other streams. These results suggest that the disturbance gradient in the Spirit Lake basin may shift the ecological costs and benefits for sex-specific flexibility in life-history strategies across the landscape. |
| Genre | Thesis/Dissertation |
| Access Condition | http://creativecommons.org/licenses/by-nc-nd/3.0/us/ |
| Topic | life-history |
| Identifier | http://hdl.handle.net/1957/54659 |
