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Date Permissions Signed

4-25-2020

Date of Award

Spring 2020

Document Type

Masters Thesis

Department or Program Affiliation

Department of Biology

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Donovan, Deborah Anne, 1964-

Second Advisor

Strom, Suzanne L., 1959-

Third Advisor

Bingham, Brian L., 1960-

Abstract

Haliotis kamtschatkana Jonas (pinto or northern abalone) is the only abalone native to the Pacific Northwest of North America. Haliotis kamtschatkana populations are in decline, and current restoration efforts in Washington State rely on out-planting hatchery-produced juveniles. Although several other abalone species are cultured extensively, little information exists on the cultivation of H. kamtschatkana, and hatchery production of this species has largely been a matter of trial and error. Hatcheries report highest mortalities in the postlarval stage, especially the first 3 to 6 months. Postlarvae feed on films of benthic diatoms, and the purpose of this study was to test 6 benthic diatom species as suitable diatom diets for H. kamtschatkana. Diatom diet suitability might rely on several factors, including morphology of the radula. The radula is a crucial feeding structure for gastropods and may display morphological plasticity, but it has never been characterized in H. kamtschatkana postlarvae. We investigated survival, growth, and radula morphology of H. kamtschatkana postlarvae when fed one of 6 benthic diatom species for 61 days post-settlement. Amphora salina best supported survival, especially in the first 20 days post-settlement (mean of 60% [SD, 22%] at day 20, mean of 47% [SD, 16%] at day 61), and Achnanthes brevipes yielded exceptionally low survival (mean of 12% [SD, 13%] and day 20, mean of 1% [SD, 3%] at day 61). Postlarvae fed Cylindrotheca closterium grew fastest among treatments (linear mixed model shell length = 293*e0.021t, measured 1,110 µm [SD, 244 µm] at day 61), followed by postlarvae fed Amphora salina, Navicula incerta, or Nitzschia laevis (no significant difference between these diets; linear mixed model shell length = 302*e0.018t, measured 894 µm [SD, 132 µm] at day 61).

We found no effect of diatom diet on radula morphology, but morphology was similar to that of other abalone species, with similar correlations between morphological characteristics and shell length. We recommend that radula development of other species may be used as a proxy for H. kamtschatkana radula development, in the absence of further investigation.

We recommend A. salina as a suitable diet for newly settled H. kamtschatkana postlarvae, and that a combination of A. salina and C. closterium be investigated to support both survival and growth.

Type

Text

Keywords

Abalone, benthic diatoms, hatchery, mariculture, morphology, feeding, postlarvae

Publisher

Western Washington University

OCLC Number

1154419960

Subject – LCSH

Pinto abalone--Mortality--Salish Sea (B.C. and Wash.); Pinto abalone--Food--Salish Sea (B.C. and Wash.); Diatoms--Salish Sea (B.C. and Wash.); Radula

Geographic Coverage

Salish Sea (B.C. and Wash.)

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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Creative Commons License

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