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A gonad conditioning study of the greenlip abalone (Haliotis laevigata)

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Lleonart, Mark (1992) A gonad conditioning study of the greenlip abalone (Haliotis laevigata). Research Master thesis, University of Tasmania.

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Abstract

The Australian greenlip abalone Haliotis laeviqata is of
commercial importance in the abalone diving industry. The
species is also believed to have culture potential and
accordingly control over reproduction is considered valuable.
The major purpose of the study was to accelerate gonad
development resulting in spawning outside the natural spawning
season.
Abalone were collected from Franklin sound in the Furneaux
group of islands off the north-east tip of Tasmania. The
important features of the conditioning tank were elevated
water temperature, the provision of water movement within the
tank to distribute feed to sedentary abalone and a diet of
preferred red algae.
Animals collected on 27 April 1990 were induced to spawn on
21 August 1990, 112 days or 1750 degree days following
commencement of gonad conditioning. The natural spawning
season of the source population was found to be November to
March.
A variety of methods for measuring reproductive development
of abalone were used. This allowed the utility of individual
methods to be examined and comparisons made between methods.
Two gonad indices, the gonad bulk index (GBI) and the modified
gonad bulk index (MGBI) were used as were a number of
assessment methods with a histological component: oocyte
size/frequency distribution, mean oocyte diameter, an ovarian
phase method and percentage mature spermatozoa. The MGBI was
considered more sensitive than the GBI, detecting first
significant gonad growth following six weeks of gonad
conditioning, compared to nine weeks for the GBI.
The gonad indices increased from initial values of 14.1 ±
4.4, n=10 and 0.4 ± 0.2, n=10 for GBI and MGBI respectively to
72.3 ± 9.2, n=10 and 7.0 ± 2.0, n=10 following 105 days of
gonad conditioning. Mean oocyte diameter (Am) increased from
30.7 ± 2.0, n=5 initially to 109.7 ± 6.0, n=5 during the same
time period. The percentage of male germ cells present as
mature spermatozoa increased from zero to 90.6 ± 16.3, n=5
following 24 weeks of conditioning.

Item Type: Thesis (Research Master)
Keywords: Abalones, Abalones, Abalone culture
Copyright Holders: The Author
Copyright Information:

Copyright 1992 the Author - The University is continuing to endeavour to trace the copyright
owner(s) and in the meantime this item has been reproduced here in good faith. We
would be pleased to hear from the copyright owner(s).

Additional Information:

Includes bibliographical references (leaves 148-162). Thesis (M.App.Sc.)--University of Tasmania, 1993

Date Deposited: 19 Dec 2014 02:34
Last Modified: 11 Mar 2016 05:55
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