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Date of Award

Spring 2025

Document Type

Masters Thesis

Department or Program Affiliation

Biology

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Cooper, W. James, 1969-

Second Advisor

Love, Brooke

Third Advisor

Olson, M. Brady (Michael Brady)

Abstract

Surf smelt (Hypomesus pretiosus) are a species of forage fish that spawn throughout the year on gravel beaches in the Salish Sea. They are a key component of maintaining a balanced and healthy ecosystem. Despite their importance, they are an understudied species, and little is known about their life history outside of their spawning behavior. Spawning on the upper intertidal region of beaches leaves embryos exposed to varying air temperatures throughout their development. In this experiment, I exposed freshly fertilized surf smelt embryos to an elevated air temperature of 26°C for 48 hours during three different stages of development to determine when they were most susceptible to thermal stress. An additional group of embryos that were never exposed to the elevated temperature were used as a control. Embryos exposed at the earliest stage of development (two days post fertilization) had the most negative response to increased temperature, with only 0.3% surviving to hatching. Embryos exposed at 4 days post fertilization (dpf) had a higher rate of hatching success than the 2 dpf treatment, but they had a high rate of physical deformities, e.g. body curvature. Embryos exposed at 6 dpf had the highest rate of hatching success among the experimental treatments and were the largest larvae at hatch. These results contribute valuable information that furthers our knowledge of this important species, while encouraging informed management decisions that support healthy ecosystems in the Salish Sea.

Type

Text

Keywords

forage fish, climate change, development, surf smelt, temperature

Publisher

Western Washington University

OCLC Number

1523694483

Subject – LCSH

Smelts--Embryos--Effect of temperature on; Smelts--Development; Smelts--Effect of global warming on; Smelts--Climatic factors

Format

application/pdf

Genre/Form

masters theses

Language

English

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author’s written permission.

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