Sharing systems and patterns of ownerships of several common small scale gears are analysed and compared with those of the small and medium trawlers operating in San Miguel Bay, Philippines. Significant differences between these two groups were found in concentration of ownership, presence of non economic social relationships between owners and crewmen, and flexibility of sharing arrangements. These differences are discussed in the terms of existing legal definitions of "municipal" and "commercial" fisheries.
The parameters a and b of the length-weight relationship of the form W=aL super(b) are presented for 37 fish species, belonging to 17 families, caught during a demersal trawl survey over the period December 1995 to March 1998 in the Gulf of Salamanca, Colombia
A trophic model of the coastal ecosystem in the waters of Bangladesh, Bay of Bengal (from the shoreline to 150 m depth) is presented. The model consists of 15 ecological groups. The biomasses of the groups (particularly the demersal species) were estimated from demersal trawl surveys conducted in the area between 1984 and 1986. The model estimated that the average trophic level of the trawl fishery catch was 2.7 in these years.
Seasonal trawling bans or closed seasons are among the most conventional management measures. They are more easily enforceable and, if implemented at the appropriate time of the year, usually produce good results. The purpose of ths paper is to describe a very successful experiment of this type undertaken recently in Cyprus, and the surprisingly good results draw attention to the particular usefulness of such a measure in very heavily overfished areas.
Mini trawlers are the smallest trawlers operating in San Miguel Bay, Philippines. This paper examines the costs and earnings of this type of gear and offers explanations for the high pure profits earned. Variations in catch and incomes are related to differences in the various sharing systems and to variations in fishing effort.
This article (in Tagalog) briefly describes the intensive multidisciplinary 3 year research project conducted by the University of the Philippines and ICLARM to document the conditions of the fisheries and fishing communities of San Miguel Bay (Philippines) so that these communities could be integrated into the development planning of the Bicol River Basin Development Project. The research project had three parts, biology, economics and sociology.
Bottom trawl surveys were conducted in the southwest monsoon season in 1996 (survey 1) and in the northeast monsoon season in 1996-97 (survey 2) throughout Vietnamese waters. The surveys mainly covered the depth zone 50-200 m but in the northeast monsoon season the depth zone 20-50 m was included in the northern and southern areas. Overall, 273 trawl hauls were conducted. The total biomass for Vietnamese waters in the depth zone 20-200 m was estimated at 700 000 t . Biomass estimates are given for the most abundant species.
We provide a review of the assemblage structure of demersal fish resources in four South and Southeast Asian countries. Multivariate techniques (classification and ordination analysis) were used to analyze scientific trawl survey data from a collaborative project in the region. Analyses covered major coastal fishing areas in Bangladesh, Indonesia, Malaysia, and the Philippines. This represents the first such assessment of fish assemblages for the region using a standard analysis framework. Results indicate that spatial patterns of demersal assemblages are influenced by depth.
The biomass of 40 ecological groups, the diet composition of prey and predators, production/biomass (P/B) and consumption/biomass (Q/B) ratios, and catches were used as basic input to parameterize an Ecopath model of the Gulf of Thailand. Following construction of a mass-balance ecosystem model, a time-dynamic simulation model (Ecosim) was used to simulate the impact of change in fishing effort. This was done using time series data to validate the historic fisheries development in the Gulf of Thailand prior to using the model for forward-looking simulations.