An egg production method for estimating spawning biomass of pelagic fish: Application to the northern anchovy, Engraulis mordax

Fishery scientists engaged in estimating the size of free-swimming populations have never had a technique available to them whereby all the parameters could be estimated from a resource survey and where no parameter values need to be assumed. Recognizing the need for a technique of this kind, the staff of the Coastal Fisheries Resources Division of the Southwest Fisheries Center (SWFC) devised an egg production method for anchovy biomass assessment. Previously, anchovy biomass was estimated by approximate methods derived from a long-time series and anchovy larval abundance, which required about 5 ma of shiptime each year to integrate the area under a seasonal spawning curve. One major assumption used in the larval abundance census method is that there is constant proportionality between larval numbers and spawning biomass. This has now proved to be erroneous. (PDF file contains 105 pages.)

Management of environmental issues for sustainable fisheries production from aquaculture in Nigeria

Aquaculture depends largely upon a good aquatic environment. The quality of the aquatic medium determines success to a large extent in aquaculture. The medium is particularly vulnerable to excessive abstraction (i.e surface or groundwater) and contamination from a range of sources (industrial, agricultural or domestic) as well as risks of self-pollution. Environmental management options proffered so far include: improvements in farming performance (especially related to feed and feeding strategies, stocking densities, water quality management, disease prevention and control, use of chemicals, etc.) and in the selection of sites and culturable species, treatment of effluents, sensitivity of recipient waters and enforcement of environmental regulations and guidelines specific to the culture system. There are presently conceptual frameworks for aquatic environment management backed by legal administrative tools to create or enforce rational system for water management, fisheries and aquaculture development strengthened by adaptive institutionalisation

Strategies for increasing freshwater fish production in the Green Revolution Programme

Sources of fish and fishery products in Nigeria were reviewed. The problems of various agencies involved in freshwater fish production in Nigeria were also analysed, such problems included shortage of manpower, inadequate training for personnel, shortage of funds, lack of infrastructures, among others