Index numbers and productivity measurement in multispecies fisheries: an application to the Pacific Coast Trawl Fleet

This study is concerned with the measurement of total factor prodnctivity in the marine fishing industries in general and in the Pacific coast trawl fishery in particular. The study is divided into two parts. Part I contains suitable empirical and introductory theoretical material for the examination of productivity in the Pacific coast trawl Deet. It is self-contained, and contains the basic formulae, empirical results, and discussion. Because the economic theory of index numbers and productivity is constantly evolving and is widely scattered throughout the economics literature, Part D draws together the theoretical literature into one place to allow ready access for readers interested in more details. The major methodological focus of the study is upon the type of economic index number that is most appropriate for use by economists with the National Marine Fisheries Service. This study recommends that the following types of economic index numbers be used: chain rather than fIxed base; bilateral rather than multilateral; one of the class of superlative indices, such as the Tornqvist or Fisher Ideal. (PDF file contains 40 pages.)

Investment opportunities in fish seed technology

An examination is made of the requirements for the commercial propagation of carp and tilapia in Nigeria. It is concluded that the operation of a successful Fish Hatchery and fry production system will depend on the following factors: 1) Correct initial planning for intended production (both species and intended numbers); 2) Design of the appropriate facilities to enable required production; 3) Selection of top calibre, dedicated and experienced hatchery staff; and, 4) The ethical responsibility taken by the hatchery management to produce only the highest quality seed under the best possible conditions. Purchasing farmers are dependent on this

Dangers and opportunities in managing temporary ponds

Although there is a growing awareness of the value of temporary ponds in Europe, there is still remarkably little information available to help guide their conservation and management. General principles which can be used to guide the management of temporary ponds as a whole have yet to be established. The aim of this article, therefore, is to give a broader overview of the main principles of temporary pond conservation, particularly by building on a number of general principles for managing ponds previously described by Biggs et al. (1994) and Williams et al. The authors emphasise the importance of surveys in order to get data on which to base management strategies. The main principles of temporary pond management are described, and examples of three case studies of ponds in England are given.

Fishpen culture as a new production system in dammed valleys in the mid-Casamance, Senegal

Fishpen culture is a possible means to increase fish production in Casamance, Senegal and to develop aquaculture without negative environmental effects. To study this possibility, a fishpen study was conducted in two dammed valleys, Guidir and Balobar in the area. Wild Sarotherodon melanotheron from 7.7 to 25.4 g and Tilapia guineensis from 7.7 to 35.0 g were stocked at densities ranging from 1.5 to 2.5 individuals/ super(m). Results are summarized in this article.

Breeding performance of Macrobrachium rosenbergii in captivity

The key factor in success of a Macrobrachium hatchery is to yield maximum number of larvae with minimum number of brooders. Suitable environmental conditions were provided and the breeding performance of females of M. rosenbergii was observed. A total number of 140 females brought from wild were used for this purpose. Each female was tagged and given a code number which made it possible to record the gestation period, interbreed period, number of breeding and larval yield of individual female during each breeding. Females were found to breed six times during the ten months duration. Of the total females studied, 99.12 % bred once, while only 2.16 % females bred six times in a total span of ten months. The average number of larvae decreased successively from first to fourth breeding. The average interbrood period was minimum between the first and second breeding and maximum between the fourth and fifth breeding. The highest average larval yield of 25,428 was recorded in the first breeding, the lowest of 4,596 in the fourth breeding. The possible reasons for variations in interbrood period and larval yield are discussed.