A practical guide for ex-ante impact evaluation in fisheries and aquaculture

This guide provides a framework for ex-ante evaluation of fisheries and aquaculture projects in developing countries. Ex-ante impact evaluations check the potential of a project or program to deliver benefits from proposed interventions. Providing extensive annotated literature citations, this guide is designed for use by practitioners who may not be fisheries or aquaculture specialists. The guide uses concepts from results-based management, organized into five modules that structure the investigation and provide insights regarding alignment of the proposed intervention with stakeholder interests, feasibility of design, potential constraints to implementation, possible impact pathways and distributional effects of the intervention. Separately published case studies of investments in Bangladesh, Malawi and Ghana illustrate application of the guide.

Studies on the occurrence of coliforms and streptococci in coastal waters of Bombay

The distribution of coliforms and streptococci in Bombay coastal waters was investigated in order to determine the state of pollution in the area. Findings show the incidence of pollution to be of a recurring nature, primarily due to discharge of raw or improperly treated sewage; thus regular monitoring of the incidence of coliforms and streptococci is of importance in determining the public health safety of the beaches and coastal waters.

Studies on the filtration, feeding and excretion rates in Perna viridis, Marcia cor and Crassostrea gryphoides (Mollusca: Bivalvia) using P³² labelled Ankistrodesmes

The study deals with a series of experiments to investigate feeding and excretion in three species of bivalves: Perna viridis (Linné), Marcia cor (Sowerby) and Cassostrea gryphoides (Gould) from Manora Channel, Karachi. Bivalves were fed with suspensions of Ankistrodesmes labelled with P³². These animals showed a considerable variation in the average filtration rates depending upon species and the body lenght. Exceptionally high content of the P³² introduced with Akistrodesmes, got excreted as pseudofaeces and faeces within first three days following its absorption as a meal. The assimilated P³² is partly released as faecal material and its major proportion is directly transferred to the solution. As expexted the gonad and kidney are the main organs found responsible for excretion as comared to other body parts. Although, the assimilated P³² is mostly concentrated in the digestive glands, the results also show a significant presence of P³² in the gonads. Accumulation of P³² was the least in the foot.

Studies on phenolase enzymes in prawns. Pt. 1. The distribution and physical properties of phenolases in Penaeid prawns

The distribution of phenolases in certain species of Penaeid prawns has been studied. Attempts were made to locate the regions of maximum enzyme activity in the prawns. The relative dopase activity has been examined in extracts from head, tail, shell with cuticles and muscle. The head juice and tail extracts were found to register very high order of enzyme activity. Metapenaeus affinis, Metapenaeus monoceros and Penaeus indicus record comparatively higher enzyme activity than Parapenaeopsis stylifera and Metapenaeus dobsoni, no definite relationship has been found between the relative activity of the enzyme and size grade at least in one species examined. Experiments were done to determine the pH optima of the enzyme and the influence of pH on its deactivation. Exposure to higher temperatures up to 55°c was shown to activate the crude enzyme considerably. The possible implications of the observations have been discussed.

Comparative studies on growth of fry of GIFT and Existing strain of Nile tilapia (Oreochromis niloticus L.)

Comparative study on growth of fry in nursery system of Genetically Improved Farmed Tilapia (GIFT) and Existing strain of Nile tilapia (Oreochromis niloticus) was performed. The trials were conducted in a series of hapa for two months. The initial mean weight of GIFT and Existing strains of tilapia were 1.03 and 1.12g, respectively and the stocking density for both the strains was maintained at 150/m³. Fishes were fed with supplementary feed 31.29% of protein level. After two months the final cumulative mean weight of GIFT and Existing strain were observed to be 8.38 and 5.51g, respectively. The net gain for weight of GIFT and existing strain were estimated to be 666% and 368% and the mean survival were 95.75% and 81.25%, respectively. The GIFT strain showed significantly (P<0.05) higher net gain in growth in weight and also higher (P<0.01) survival than that of existing strain.

Studies on the induced breeding and post-larval rearing of shing (Heteropneustes fossilis Bloch)

An experiment was conducted on induced breeding and fry rearing of shing, Heteropneustes fossilis (Bloch) in the Department of Aquaculture, Bangladesh Agricultural University for a period of four months from April to July 1994. Hatching rate was calculated at 21.50h and was found to be 45 to 55 % and the survival rate of larvae was 30 to 40 % at 26 to 29°C. Survival rate and growth rate of post larvae were found to be 50 to 60% and 96.6 to 117.2% respectively. Feed-3 (F3) showed the highest survival rate and growth rate of post larvae.

Studies on the gonadosomatic index and fecundity of chapila (Gudusia chapra Ham.)

The study was conducted in pond to determine the fecundity and gonadosomatic index of chapila, Gudusia chapra. The male fish was found to attain sexual maturity at 7.7 cm and 7.41 g and that of the female at 9.3 cm and 14.65 g by standard-length and body-weight respectively. The investigated fishes were found to be male and female at the ratio of 1:3 and generally female was found to be larger than male. The fish was found to spawn for several months with two spawning peaks, one in April and another in August as indicated by the peaks of gonadosomatic index and ova diameter. Fecundity of the fish ranged from 25,220 to 154,528 with an average value of 72,383 and was found to increase with the increase in length and weight of the fish. The relationships between fecundity and standard-length, body-weight, gonad-length and gonad weight of the fish were found to be linear and significant.

Studies on fecundity, sex ratio and crossbreeding in different strains of Guppy

Studies on the fecundity, sex ratio and crossbreeding in different strains of the guppy Poecilia reticulata such as Butterfly I, Butterfly II and Cobra strains was carried out. The highest fecundity among Butterfly I strain was at the 5th breed while it was highest at the 6th and 8th breed among Butterfly II and Cobra strain respectively. The average male percentage was 39.88%, 43.39% and 45.02% among Butterfly I, Butterfly II and Cobra strains respectively. The crossbreeding of strains showed good results among crossbreeds of Butterfly II (♀) X Cobra (♂) and Butterfly I (♀) X Cobra (♂). The crossbreed among the Butterfly I (♀) X Cobra (♂) proved to be excellent from the point of view of more percentage, rapid growth, and brilliant body and finnage colouration.

Further studies on the water bugs of the genus Anisops (Hemiptera:Notonectidae) in Ceylon

In the present paper a short account is given of the biology of Anisops in Ceylon, their distribution and descriptions of Anisops ali and A. occipitalis. All the other Ceylonese species are described by Leong and Fernando (1962 . Brooks (1951) has given detailed descriptions of all the Ceylonese species except Anisops ali. A revised key to the Ceylonese Anisops is given and includes for the first time A. ali whose male has so far not been described and therefore omitted from the keys of Brooks (1951) and Leong and Fernando (1962).

Some key concepts in fisheries research and management, with emphasis on Mozambique

Some basic concepts of fishery economics and management, and fish population dynamics are recalled, as presented during a course held at the Instituto de Investigaçāo Pesqueira from 23 February to 15 March 1988 in Maputo, Mozambique. Also, some basic elements of length-based stock assessment are reviewed, with emphasis on their implementation through the “Compleat Elefan" package, used extensively during this course, when the participants analyzed their data and wrote first draft of manuscripts incorporating the results of these analyses. Some problems relative to sampling and to seasonal growth oscillations are discussed with special reference to conditions in Mozambique.

Studies on the fish ponds at Pitipana, Negombo 1: seasonal and diurnal variation of some hydrobiological factors

The present paper is a part of a detailed investigation on the biology of grey mullet, Mugli cephalus L., and the feasibility of its culture in the brackish waters of Sri Lanka. The authors present the results of investigation on the water quality of five experimental ponds at the Pitipana Brackishwater Fisheries Station, Negombo, carried out over a period of one year, December 1976 to November 1977, together with studies on the primary productivity are presented.

Studies on the preparation of fish silage. 1. Effect of quality of raw material and type of acid

An experiment was undertaken in which silver bellies (Leiognathus splendens) of different quality were used to produce silages using different concentrations of hydrochloric acid and formic acid. The quality and storage life of the various preparations are reported. Silages which keep for at least 30 days can be produced from silver belly held for 3 or 12 hours at 28°C by: 1) reducing the pH by addition of hydrochloric acid; 2) adding 0.5% formic acid and reducing the pH to 3.5 with hydrochloric acid; or 3) adding 2.5% formic acid.

Studies on the preparation of fish silage. 2. Rate of liquefaction in different parts of silver belly

An experiment was undertaken to determine from which part of silver belly (Leiognathus splendens) carcasses originate the autolytic enzymes responsible for liquefaction of silage. Findings show that it is important to leave head and viscera present in order to get a satisfactory liquefaction in silage prepared from silver belly using 3.5% formic acid. The storage life of silage produced from various parts of the fish carcasses is also discussed.