Recommendation domains for pond aquaculture

This publication introduces the methods and results of a research project that has developed a set of decision-support tools to identify places and sets of conditions for which a particular target aquaculture technology is considered feasible and therefore good to promote. The tools also identify the nature of constraints to aquaculture development and thereby shed light on appropriate interventions to realize the potential of the target areas. The project results will be useful for policy planners and decision makers in national, regional and local governments and development funding agencies, aquaculture extension workers in regional and local governments, and researchers in aquaculture systems and rural livelihoods. (Document contains 40 pages)

Recommendation domains for pond aquaculture: country case study: development and status of freshwater aquaculture in Malawi

This monograph is a result of a 3-year project to produce a decision-support toolkit with supporting databases and case studies to help researchers, planners and extension agents working on freshwater pond aquaculture. The purpose of the work was to provide tools and information to help practitioners identify places and conditions where pond aquaculture can benefit the poor, both as producers and as consumers of fish. This monograph is the case study for Malawi. Written in three parts, it describes the historical background, practices, stakeholder profiles, production levels, economic and institutional environment, policy issues, and prospects for aquaculture in the country. First, it documents the history and current status of the aquaculture in the country. Second, it assesses the technologies and approaches that either succeeded or failed to foster aquaculture development and discusses why. Third, it identifies the key reasons for aquaculture adoption.

Recommendation domains for pond aquaculture: country case study: development and status of freshwater aquaculture in Cameroon

This report is an output of the project “Determination of high-potential aquaculture development areas and impact in Africa and Asia”. This monograph is the case study for Cameroon. Written in three parts, it describes the historical background, practices, stakeholder profiles, production levels, economic and institutional environment, policy issues, and prospects for aquaculture in the country. First, it documents the history and current status of the aquaculture in the country. Second, it assesses the technologies and approaches that either succeeded or failed to foster aquaculture development and discusses why. Third, it identifies the key reasons for aquaculture adoption.

Recommendation domains for pond aquaculture: country case study: development and status of freshwater aquaculture in Bangladesh

This report is an output of the project “Determination of high-potential aquaculture development areas and impact in Africa and Asia”. This monograph is the case study for Cameroon. Written in three parts, it describes the historical background, practices, stakeholder profiles, production levels, economic and institutional environment, policy issues, and prospects for aquaculture in the country. First, it documents the history and current status of the aquaculture in the country. Second, it assesses the technologies and approaches that either succeeded or failed to foster aquaculture development and discusses why. Third, it identifies the key reasons for aquaculture adoption.

Recommendation domains for pond aquaculture: country case study: development and status of freshwater aquaculture in Henan Province, China

This monograph is the case study for China, with a particular focus on Henan Province, the project location. Written in three parts, it first describes the historical background, production levels and trends, economic and institutional environment, policy issues, and market situation in China in general. The main part of the study presents findings from two different surveys conducted in Henan Province. County-level information is used to analyze the current situation of aquaculture, providing a more disaggregated picture than what is generally available from national statistics. Data collected in a survey of fish farmers in two locations in Henan are then analyzed with regard to the prevailing aquaculture technology and production practices, economic performance of pond fish farming, and the key reasons for aquaculture adoption. In the final chapter, constraints and opportunities for the aquaculture sector in China in general are discussed. (pdf contains 68 pages.)

Stocks of Dolphins (Stenella spp. and Delphinus delphis) in the Eastern Tropical Pacific: A Phylogeographic Classification

Current information is reviewed that provides clues to the intraspecific structure of dolphin species incidently killed in the yellowfin tuna purse-seine fishery of the eastern tropical Pacific (ETP). Current law requires that management efforts are focused on the intraspecific level, attempting to preserve local and presumably locally adapted populations. Four species are reviewed: pantropical spotted, Stenella attenuata; spinner, S. longirostTis; striped, S. coeruleoalba; and common, Delphinus delphis, dolphins. For each species, distributional, demographic, phenotypic, and genotypic data are summarized, and the putative stocks are categorized based on four hierarchal phylogeographic criteria relative to their probability of being evolutionarily significant units. For spotted dolphins, the morphological similarity of animals from the south and the west argues that stock designations (and boundaries) be changed from the current northern offshore and southern offshore to northeastern offshore and a combined western and southern offshore. For the striped dolphin, we find little reason to continue the present division into geographical stocks. For common dolphins, we reiterate an earlier recommendation that the long-beaked form (Baja neritic) and the northern short-beaked form be managed separately; recent morphological and genetic work provides evidence that they are probably separate species. Finally, we note that the stock structure of ETP spinner dolphins is complex, with the whitebelly form exhibiting characteristics of a hybrid swarm between the eastern and pantropical subspecies. There is little morphological basis at present for division of the whitebelly spinner dolphin into northern and southern stocks. However, we recommend continued separate management of the pooled whitebelly forms, despite their hybrid/intergrade status. Steps should be taken to ensure that management practices do not reduce the abundance of eastern relative to whitebelly spinner dolphins. To do so may lead to increased invasion of the eastern's stock range and possible replacement of the eastern spinner dolphin genome.(PDF file contains 24 pages.)

Chromosomal and histological evidences of infertility in F2 and F2 backcross. Hybrid generations of Clarias anguillaris and Heterobranchus longifilis

Male meiosis was studied in 9 different mating combinations in parental, first, second and backcross generation hybrids of Clarias anguillaris and Heterobranchus longifilis. 27 bivalents were recorded in metaphase I for seven mating combinations. The number of bivalents in F1 hybrid male x C. anguillaris female could not be determined due to a high degree of clumping of the chromosomes. All metaphase I cells observed in female F1 hybrid x male H. longifilis had three complex bivalents consisting of 43.3% giant ring and 56.7% giant rod chromosomes. The number of ring bivalents per cell was higher in parental H. longifilis than parental C. anguillaris. The number of ring bivalents per cell increased from F1 (6.7 and 8.2) to F2 backcross (13.5) hybrid generations indicating increasing chromosomal instability of backcross hybrids over Fl and F2 hybrids

Growth response, feed conversion rate and cost benefits of hybrid catfish fed maggot meal based diets in outdoor tanks

The growth response, feed conversion ratio and cost benefits of hybrid catfish, Heterobranchus longifilis x Clarias gariepinus fed five maggot meal based diets were evaluated for 56 days in outdoor concrete tanks. Twenty-five fingerlings of the hybrid fish were stocked in ten outdoor concrete tanks of dimension 1.2mx0.13mx0.18m and code MM sub(1)-MM sub(5) in relation to their diet name. Five isonitrogenous and isocaloric maggot meal based diets namely MM sub(1)-0% maggot meal, MM sub(2)-25% maggot meal, MM sub(3)-50% maggot meal, MM sub(4-)75% maggot meal and MM sub(5-) 100% maggot meal were used for the experiment. The higher the proportion of maggot in the meal, the higher the ether extract and crude fiber. No significance difference P>0.05 exists between ash content of the experimental diets. Diet MM sub(2) had the best growth performance and highest MGR with a significant difference P<0.05 with other diets fed fish. No significance differences P>0.05 exists between the growth parameters for diets MM sub(1), MM sub(3), and MM sub(4). A positive correlation (r=1.0) exists (P<0.05, 0.25) between the growth parameters for the different experimental diets. Highest correlation r super(2)=0.9981 exists P<0.05 between MGR within the treatments. However, there no significant (P>0.05) difference in expenditure but there is between the profit indices and incidence of cost between the trials. MM sub(2) has the best yield cost and net profit. Without any reservation, inclusion of maggot based meal diet is recommended as feed of hybrid catfish to 75% inclusion for growth and profit incidence

Growth response and survival of F1 hybrid fry of Heterobranchus longifilis and Clarias gariepinus reared in glass aquaria and plastic basins

The growth response of F1 hybrid fry of female Heterobranchus longifilis and male Clarias gariepinus were investigated under laboratory conditions in glass aquaria glass tanks and plastic basins. The larvae were produced artificially after inducement with Ovarptim. The hatching percentage was very high. Weekly mean length and weight were monitored for 6 weeks. The average length increase was higher in aquaria glass tanks than in plastic basins. However, there were depressed and irregular weight increases in both types of rearing troughs while significant weight increase (P<0.05) was recorded at week 6 in the plastic basin. Generally, the growth rate and survival in both containers were not significantly different

The survival and growth of hybrid Clarias gariepinus and Heterotis longifilis fed with live and frozen Dapthnids

Six glass tanks, each containing dechlorinated tap water and stocked with 3-day-old Heterobranchus, larvae hybrid between, Heterobranchus longifilis (male and Clarias gariepinus (female) were administered two types of feeding trials viz: live and frozen Dapthnids. Each treatment was replicated three times. The larvae were each fed approximately 50 Dapthnids per feeding time for fifteen days. Morphometric measurements of weigh and total length were taken before and after the experiment, and water quality parameters were monitored throughout the experimental period. At the end of the experiment, fish larvae fed frozen, Dapthnids, showed higher survival rate than Heterobranchus fed live Dapthnids. Even though the statistical analysis revealed that there was no significant difference (P>0.05) in survival. However, the Heteroclarias fed live dapthnids performed better in terms of growth rate than Heteroclarias fed frozen dapthnids. The statistical analysis did not show significant difference (P>0.05) between the final length and weight of two treatments. Heteroclarias fed live dapthnids had higher length and weight than Heteroclarias fed frozen dapthnids. It was therefore concluded that based on this experiment there is the likelihood that frozen zooplankton (Daphnids) do not encourage growth of Heteroclarias, but improves its survival. However, it's suggested that frozen zooplankton can be used to supplement live zooplankton in situation of sacrcity

Potential of grouper hybrid (Epinephelus fuscoguttatus x E. polyphekadion) for aquaculture

The marine grouper species are considered high value food fish in several countries. However, controlled breeding and hatchery production of grouper fingerlings for commercial farming is still in its infancy. Investigations on the growth performance of the brown marbled grouper Epinephelus fuscoguttatus (Forskal), camouflage grouper E. polyphekadion (Bleeker) and their hybrid (E. fuscoguttatus x E. polyphekadion) under hatchery and growout culture conditions indicate the potential of grouper hybrids for aquaculture.

The commercial use of chicken processing wastes to raise hybrid catfish (Clarias gariepinus) x Clarias macrocephalus) in Thailand

The article highlights the commercial use of chicken processing wastes on nursery and growout operations of hybrid catfish (Clarias gariepinus x Clarias macrocephalus) farm in Thailand.

Portable canvas tanks for culture of hybrid catfish (Clarias gariepinus x Clarias macrocephalus) by small-scale farmers in Malaysia

This paper describes the trials made with a simple portable canvas-tarpaulin tank system developed at the University Sains Malaysia for culture of hybrid catfish (Clarias gariepinus x Clarias macrocephalus) by Malaysia small scale farmers.