Relationships between the harpacticoid copepod Tigriopus californicus Baker and post larval red abalone, Haliotis rufescens Swainson

Graduation Date

1984

Document Type

Thesis

Program

Other

Program

Thesis (M.S.)--Humboldt State University, Natural Resources, Fisheries, 1984

Committee Chair Name

George Allen

Committee Chair Affiliation

HSU Faculty or Staff

Keywords

Mortality, Tigriopus californicus (Baker), Humboldt State University -- Theses -- Fisheries, Abalones, Copepoda

Abstract

High post-larval abalone mortality is a major problem for abalone culturists today. The purpose of this study was to determine if the copepod (Tigriopus californicus) caused mortalities among larval abalone (Haliotis rufescens). A significant (P0.01) relationship existed between the concentration of copepods and abalone mortality. However, no significant difference of mortality was found between abalone with copepods directly in cultures or abalone with only copepod effluent water passed into cultures. Therefore, copepods did not directly kill abalone. Indirect exposure of copepods to abalone were investigated by analyzing water quality parameters. Bacterial studies showed a trend of increasing concentration of Vibrio anguillarum with increasing concentrations of copepods. Species in the genera Vibrio are deadly to fish and shellfish in the marine environment. Thus, V. anguillarum was suspected as the primary cause of young abalone mortality in this study. Ultraviolet treated seawater and the antibiotic neomycin were tested in abalone cultures with and without copepods to determine if Vibrio free conditions increased abalone survival. Treated abalone cultures were Vibrio free and contained abalone which survived superior to non-treated, Vibrio present groups.

https://scholarworks.calstate.edu/concern/theses/70795b047

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