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Date Permissions Signed

5-31-2022

Date of Award

Spring 2022

Document Type

Masters Thesis

Department or Program Affiliation

Huxley College of the Environment, Marine and Estuarine Science

Degree Name

Master of Science (MS)

Department

Environmental Sciences

First Advisor

Bingham, Brian L., 1960-

Second Advisor

Sobocinski, Kathryn L.

Third Advisor

Pearce, Christopher

Abstract

There has been recent interest in Washington State, USA in the culture of the California sea cucumber (Apostichopus californicus) for both wild-stock enhancement and as an aquaculture resource. The species is a good candidate for Integrated Multi-Trophic Aquaculture (IMTA), where the animals are supported entirely on the excess organic biodeposits from existing floating aquaculture operations (e.g., bivalves or finfish). In IMTA, excess nutrients and organic materials from higher-trophic-level organisms are taken up by lower-trophic-level species, providing both environmental benefits and secondary products for sale. Unfortunately, a reliable longterm tagging and tracking method is not currently known for A. californicus, which has negatively impacted management of the wild fishery and complicates IMTA efforts. A tagging method is needed for both entities to delineate wild individuals from cultured. To resolve this problem, I tested four tagging methods on large and small sea cucumbers: 1) a stainless-steel suture through the body wall, 2) a stainless-steel suture through the cloaca, 3) an 8-mm PIT tag inserted into a tentacle, and 4) a papilla clip. Tag retention time, water parameters, and stress indicators were monitored throughout the study. In a second study, controlled mesocosms were used to measure feeding of A. californicus on three diets that replicated the waste deposited under floating aquaculture – mussel biodeposits, biodeposits mixed with the algae Palmeria mollis, and P. mollis alone. I specifically examined whether A. californicus processed different quantities of the three waste types, and whether different size sea cucumbers removed different quantities of carbon and nitrogen from the waste. In a third study, A. californicus were deployed beneath existing Mytilus galloprovincialis aquaculture rafts to assess the effects of A. californicus density (2 or 4 individuals m-² (top, bottom, and side cage area)) and location (directly under raft or 250 m away from raft) on survival, growth, and nitrogen and carbon assimilation. Results indicate that sea cucumbers tagged with a body wall tag exhibited the longest median retention time (87 and 72 days for small and large individuals) with no additional stress than was seen in untagged control sea cucumbers. Feeding experiments revealed that sea cucumbers will more effectively assimilate nutrients from waste types that are higher in organic quality, and that larger sea cucumbers processed more of the P. mollis diet than they did the other diets. In the third study, sea cucumbers that were grown at a density of 2 individuals m-² exhibited a higher growth rate than those that were grown at a density of 4 individuals m-² under mussel aquaculture with maximum growth in late summer. Carbon and nitrogen present in cage biodeposits sediments were reduced in late summer when sea cucumber were present in cages. However, density had no effect. By the end of the study, the organic quality of mussel biodeposits had dropped to the point that there was no obvious effect of sea cucumber on total carbon or nitrogen in cage sediments. The three components of this study increase our understanding of A. californicus as potential subjects for multitrophic aquaculture. Specifically, I suggest options to improve tracking of A. californicus and inform resource managers of seasonally dependent nutrient assimilation when A. californicus are farmed under mussel aquaculture.

Type

Text

Keywords

Apostichopus californicus, Mytilus galloprovincialis, California Sea Cucumber, Mediterranean Mussel, Integrated Multitrophic Aquaculture, IMTA, Aquaculture

Publisher

Western Washington University

OCLC Number

1322485739

Subject – LCSH

Sea cucumbers--Research--Washington (State); Aquaculture--Research--Washington (State); Sustainable aquacuture; Fish tagging--Washington (State)

Geographic Coverage

Washington (State)

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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