Shrimp farming is considered a “risky business” and often compared to gambling for farmers. It is associated with a diverse range of risks and uncertainties, including volatile markets, climate variability, and production risks. In order to mitigate the effects of unpredictability farmers may decide on a particular stocking density and adopt different risk management strategies.
The success of marine stocking programs hinges on releasing hatchery-produced juvenile animals into the optimal marine habitat. This study sought to identify optimal microhabitat features of coastal seagrass meadows for juvenile sea cucumbers Holothuria scabra, a species cultured widely for stock restoration, sea ranching and sea farming.
A brief account is given of a workshop organized by the South Pacific Research Coordination Unit of the ForumFisheries Agency in order to examine the use of length frequency data as a tool in fish population assessment in the South Pacific region. The workshop concentrated on the ELEFAN suite of programmes and length frequency data for species from a variety of taxa and habitats were analyzed.
The introduction of Tilapia rendalli in Lake Sauce is described,outlining the various biological investigations which were necessaryfor management of the lake and biomass estimation, age determinationand overcrowding.
An assessment is made of the Indian Ocean yellowfin tuna (Thunnus albacares ) stock, using data from a sport fishery in the Pemba Channel off the Kenya-Tanzania border in conjunction with commercial catch figures for theIndian Ocean. The long-term maximum sustainable yield is estimated to be around 113,000 tons/annum; dataindicate that catch levels of yellowfin tuna in the Indian Ocean exceed the MSY by a dangerous amount.
Relative biomass per recruit of adult (i.e. sexually mature) fin to shellfish is shown to help in identifying levels of fishing mortality likely to lead to recruitment overfishing. This is illustrated with data from a Malaysian penaeid shrimp fishery.
The Tuna and Billfish Assessment Programme is a 3-year programme designed to provide a better understanding of the stocks of tuna and billfish throughout the central and western Pacific and also to determine the status of the stocks of the commercially important species. It will provide data as a basis for the assessment of optimum yields and will provide governments with information upon which sound fisheries development and resource management can be based. The specific topics to be covered by the Programme are listed.
A brief account of the USAID funded fish stock assessment collaborative Research Support Program is given, with emphasis on its Philippine module, devoted to empirical analyses, modelling and field studies aimed at improved management of exploited multispecies fish stocks.
Tropical sea cucumber mariculture has potential to become a profitable industry and contribute towards natural population replenishment. Here, we synthesise the fields of progress, current impediments and research opportunities in tropical sea cucumber aquaculture arising from recent studies and an Indo-Pacific symposium. We present novel comparisons of data from hatcheries, earthen ponds and sea pens from published and unpublished studies in various countries. Of the few tropical species to have been cultured, only the sandfish Holothuria scabra has been bred extensively.
The Abbassa selection line (developed by selective breeding) and the Kafr El Sheikh commercial strain (widely used in Egypt), both Oreochromis niloticus, were compared at two stocking densities (two and four fish m-2). Harvest weight, length, depth, width and head length were recorded. The Abbassa line showed a superior harvest weight (28 per cent) over the Kafr El Sheikh strain. Males were heavier than females, but the between-sex difference was greater in the commercial than in the Abbassa line (39 and 31 per cent respectively).