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Title The captive propagation and rearing of the Silver Kob, Argyrosomus Inodorus in Namibia
Full text http://hdl.handle.net/1995/325
Date 2008
Author(s) Tjipute, Martin
Abstract A RESEARCH PROPOSAL SUBMITTED IN FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY THE UNIVERSITY OF NAMIBIA BY MARTIN TJIPUTE, OCTOBER, 2007 Main Supervisor: Dr Lawrence Keith Oellermann,(University of Namibia) Co-supervisor: Prof Pieter Britz (Rhodes University, South Africa) - The Namibian Government has identified aquaculture as a key growth area in the diminishing fishing sector. The Namibian marine aquaculture industry has concentrated on oyster farming for the most part, but the sub-sector needs to diversify away from shellfish to allow for future growth and stability. For most of the Namibian coast, marine aquaculture is restricted to onshore farming in ponds or tanks. This is relatively expensive, and therefore limits cultivation to higher-value species, such as the silver kob, Argyrosomus inodorus. This indigenous fish belongs to the Sciaenidae, a family of marine fishes currently under investigation for their culture potential in countries as diverse as South Africa, Australia and the USA. The silver kob grows relatively quickly, is sort-after for its palatability, can be induced to spawn under artificial conditions and is commonly available, making up some 70% of recreational shore angling catches and 58% of all line fish catches in Namibia. The silver kob appears to be a strong candidate for aquaculture in Namibia, and this project aims to investigate key aspects of the propagation, husbandry, larviculture, environmental tolerances, growth and survival of the species under captive conditions; in order to assess its potential. The study will be conducted at the Sam Nujoma Marine and Coastal Resources Research Centre's marine research facility, using broodstock fish caught in the wild at Toscanini Bay in the Skeleton Coast Nature Reserve, and larvae and juveniles propagated at SANUMARC. The project will consist of six parts, including an examination of the reproductive biology of silver kob using fish sampled throughout the year; the development of a spawning protocol for brood stock fish using hormonal and environmental induction; a description and photographic documentation of the egg and larval development of the species; the development of a technique for the larviculture of silver kob; the development of a method to wean post-larvae from live to inert artificial food, and the observation of the effects of different feeding regimes on the growth and survival of these fish; and lastly, the elucidation of the temperature preference of the species, and it's tolerances for the key limiting environmental factors in tank culture, such as oxygen levels and ammonia concentrations. Data obtained from the conducted experiments will be analyzed using descriptive and comparative statistical methods, represented graphically where possible, and through the use of photomicrographs. Where comparative experiments are carried out, all treatments will be replicated in triplicate, and variability between samples will be tested for significance (P < 0.05) using ANOVA. Relationships between the treatments will be described using an appropriate multiple range test. Using the silver kob as the study vehicle, the project will introduce marine fin-fish aquaculture to Namibia, resulting in the development of appropriate husbandry practices and hatchery and on-growing protocols. This is a necessary step to allow the Namibian marine aquaculture industry to diversity away from its dependence on molluscan shellfish farming.
Subject(s) Captive propagation; Rearing; Silver Kob; Argyrosomus Inodorus; Namibia; Marine aquaculture; Kob
Language en
Relation Postgraduate Studies Centre: Research proposals
Type of publication Thesis
Format 168448 bytes; 32768 bytes; application/msword; application/msword
Repository Windhoek - University of Namibia
Added to C-A: 2011-06-07;13:50:48