Conservation needs of fisheries resources and reorientation for sustainable captive and culture practices

A discussion is presented on the importance of conservation of fishery resources, considering in particular the situation in Nigeria and providing also an outline of various legislations made by government. Suggestions are given regarding the following: education on the importance of conservation; fish farming or aquaculture; restocking or rejuvenation of depleted water bodies; stock assessment; monitoring and surveillance; provision of fishing inputs; and, extension research linkage

Hatchery and culture technology for the sea cucumber Holothuria scabra Jaeger, in India

The seed of the sea cucumber Holothuria scabra jaeger is being produced at the Central Marine Fisheries Research Institute in India. This article describes the techniques being used in the production of seed and the experiments being carried out for the rearing of juveniles. Trials to grow juveniles in hatcheries on prawn farms have shown spectabular results that are both cost efficient and environmentally friendly.

Prawn culture and policy options: technology import and culture through fishermen vis a vis industry

Recent developments in aquaculture has created an awareness that prawn culture is a dollar spinner, in which industry can step in to earn foreign exchange by producing an expensive food iten which has a high market demand abroad. The Government has to take a policy decision whether the prawn culture should be done through small fishermen to improve their socio-economic condition or through private industry with the high technology input and predefined objectives of export trade. Perhaps a simultaneous operation of the two could be allowed best in the interest of India. Perhaps in the interest of quick development and adoption of high production technology, through fishermen organization, the development is encouraged through the implimentation of welfare and area development schemes. In some selected areas private industry may be encoureged to use high production technology to develop prawns.

Eyes on their fingertips: some aspects of the arts, science, technology and culture of the fisherfolk of Trivandrum, India

Eyes on Their Finger Tips deals with the traditional marine wisdom of a set of people and the rarest of rare experiences they have had at sea. Through these numerous chapters he takes us into the seas of the fishers. It is a voyage which we cannot make in reality. But through the heroic deeds of his father, the riddles of oldman Sebesti, the shark story of brother Kamalappan, and the rituals of his mother, we get a fascinating peep into the wisdom of the watery world of the small-scale fishers of Trivandrum, Kerala, India.

Seed production and culture techniques of Genetically Improved Farmed Tilapia (GIFT) in brackishwater environment

Effects of different levels of salinity on survival, growth and gonadal development of Genetically Improved Farmed Tilapia (GIFT) were studied under laboratory conditions in glass aquarium, for a period of ten weeks. The initial individual size of the GIFT was 20.23±4.45 and the salinity levels tested were 0, 5, 10, 15 and 20 ppt. The highest survival of 87.5% was found in 0 ppt and the lowest 60.5% in 20 ppt. Though the survival decreased progressively with increased salinity, there were no significant differences (P>0.05) among 0, 5, and 10 ppt. Similar to what has been observed in survival, the specific growth rate (SGR %/day) also decreased as of 1.30, 1.24, 1.08, 0.90 and 0.71, respectively, with the increased salinity of 0, 5, 10, 15 and 20 ppt. The gonadal development was highest in 0 ppt with a GSI value of 3.75 and lowest of 2.01 in 20 ppt. In the second experiment, gonadal development and seed production performance of GIFT in brackishwater condition were investigated for a period of three months. Each of the three fine meshed hapas of 20 square meters made from nylon net was placed in a freshwater (0 ppt) and in a brackish water (10-15 ppt) pond of the Brackishwater Station (BS). GIFT of 65 g average weight from a single cohort were stocked into three hapas at a rate of 2 per m. The male vs female ratio was 1:3. The development of gonad was faster with the higher gonadosomatic index (GSI %) of 3.85 % in freshwater condition than that of 2.73 % in brackish water. Within three months of the study period, a total of 70,510 and 44,250 GIFT fry were produced respectively, in freshwater and brackishwater conditions. Finally under third experiment, a participatory on-farm trial was carried out to evaluate the production performance of GIFT in monoculture and in polyculture with silver barb in coastal freshwater pond conditions. Nine ponds were selected for three treatment combinations of GIFT monoculture (T1), GIFT and silver barb polyculture (T2), and silver barb monoculture (T3). The ponds have been stocked in April, 05 at a density of 25,000 fry per ha. Fishes were fed with rice bran at the rate of 6% bw per day. In one month culture period, GIFT attained an average weight of 16.27 g in monoculture and 17.23 g in polyculture, against an average stocking weight of 0.37 g. Silver barb reached an average weight of 16.62 g in polyculture with GIFT and 10.01 g in monoculture, against an average stocking weight of 3.79 g.

Seed production and culture techniques of climbing perch, Anabas testudineus

Six treatments each with 12 replications designed to optimize the dose of inducing agent PG to achieve fertilization and hatching success of climbing perch, Anabas testudineus were tested. The females were given single injection of 7-12 mg PG/kg body weight and the males were given 4 mg PG/kg body weight. Fertilization and hatching rate varied from 67±4.55% to 66±3.0% and 59±4.88% to 57±6.21% for the doses of 10, 11 and 12 mg PG/kg of body weight, respectively. The hormone dose had significant (P<0.05) effect on fertilization and hatching. Six mini shallow cisterns (570 cm x 105 cm) were used to investigate the efficacy of zooplankton and Artemia nauplii as feed for spawn rearing. Three-day old spawns were stocked in six mini shallow cisterns at a stocking density of 100 individuals/L of water. Two treatments each with three replications were used to develop culture technique of the climbing perch. In case of treatment-1, the spawns were fed with Artemia nauplii three times daily, while in treatment-2, zooplankton were used as feed in the same manner as in treatment-1. After 14 days of rearing, mean final weight of the fry of treatments-1 and 2 were 95.55±6.71 and 57.69±5.40 mg, respectively. In treatment-1, spawn fed with Artemia nauplii showed significantly (P<0.05) higher mean weight than the spawn fed with zooplankton (treatment 2).

Prospect of fishery, utilisation and culture of crabs in India

Investigations on the fishery, utilization and development of the crabs in Indian waters have been reviewed. Various factors relating to the improvement of fishery, keeping quality of the crab meat and possibilities for an integrated farming of commercially important crabs are discussed.

Identification and culture of common diatoms as possible feed for Penaeus monodon

Diatoms were collected from Buyuan Bay, and from the hatchery tanks at Tigbauan, to determine the commonly occurring species, the feasibility of culturing these species, and the potential of these selected species as food for larval P. monodon. The commonly occurring diatoms were identified as Chaetoceros calcitrans, Navicula grimmei, Nitzchia seriata, Nitzchia closterium and Amphiprora sp. These diatoms were isolated and unialgal cultures prepared. Protein content analysis using the micro-Kjildahl method gave the following result: C. calcitrans, 11 . 78%; Nitzchia seriata, 25%; Nitzchia closterium, 30 . 5%; Navicula grimmei, 9 . 06% and Amphiprora sp. 8 . 96%. Feeding experiments were conducted to determine acceptability of the different diatom species and percentage survival of larval stages Z SUB-1 -M SUB-2 . Larvae were placed in 4-l capacity plastic containers with a stocking density of 10/l. The results of several feeding trials using the different mass-produced diatoms are summarized. From the data gathered, C. calcitrans appears to be the most promising candidate as feed for zoea and mysis stages of P. monodon. The average percentage survival of C. calcitrans was 63 . 76% for the 3 trials, and as high as 82 . 22% in the third trial. Comparatively high percentage survival of larvae was also recorded when Nitzchia seriata (48 . 17%) and Nitzchia closterium (67 . 6%) were given as feed, while both Amphiprora sp. and Navicula grimmei gave 0% survival. The poor results with Amphiprora sp. and Navicula grimmei may be due to their low protein content (8 . 96% and 9 . 06%, respectively) and the inability of the larvae to ingest them. Navicula and Amphiprora were observed to cling to the appendages of the larvae and to settle down in the medium making them unavailable to the larvae. Low survival was also noted when frozen C. calcitrans was used (14 . 25%). This may be due partly to the effect of the floculating agent (ALSO SUB-4 . 25 g/l) used in concentrating the diatoms. When protein contents of C. calcitrans, N. seriata and N. closterium are compared, the 2 Nitzchia species have relatively higher protein contents than C. calcitrans and, therefore, could be the more desirable feed candidates. However, few feeding trials were made using Nitzchia so that additional investigations will have to be done on this aspect.

Isolation and culture in artificial media of Lagenidium from Penaeus monodon larvae

Fungal infection of P. monodon larvae is a problem in hatchery operations. The fungus, which attacks the nauplius to postlarval stages and causes up to 100% mortality, has been tentatively identified as belonging to the genus Lagenidium . This pathogenic organism has recently been isolated and cultured. A description is given of the fungus, and features of its biology and pathology are discussed.

Proceedings of the International Workshop on age determination of oceanic pelagic fishes: Tunas, billfishes, and sharks, Miami, Florida, February 15-18,1982

Accurate and precise estimates of age and growth rates are essential parameters in understanding the population dynamics of fishes. Some of the more sophisticated stock assessment models, such as virtual population analysis, require age and growth information to partition catch data by age. Stock assessment efforts by regulatory agencies are usually directed at specific fisheries which are being heavily exploited and are suspected of being overfished. Interest in stock assessment of some of the oceanic pelagic fishes (tunas, billfishes, and sharks) has developed only over the last decade, during which exploitation has increased steadily in response to increases in worldwide demand for these resources. Traditionally, estimating the age of fishes has been done by enumerating growth bands on skeletal hardparts, through length frequency analysis, tag and recapture studies, and raising fish in enclosures. However, problems related to determining the age of some of the oceanic pelagic fishes are unique compared with other species. For example, sampling is difficult for these large, highly mobile fishes because of their size, extensive distributions throughout the world's oceans, and for some, such as the marlins, infrequent catches. In addition, movements of oceanic pelagic fishes often transect temperate as well as tropical oceans, making interpretation of growth bands on skeletal hardparts more difficult than with more sedentary temperate species. Many oceanic pelagics are also long-lived, attaining ages in excess of 30 yr, and more often than not, their life cycles do not lend themselves easily to artificial propagation and culture. These factors contribute to the difficulty of determining ages and are generally characteristic of this group-the tunas, billfishes, and sharks. Accordingly, the rapidly growing international concern in managing oceanic pelagic fishes, as well as unique difficulties in ageing these species, prompted us to hold this workshop. Our two major objectives for this workshop are to: I) Encourage the interchange of ideas on this subject, and 2) establish the "state of the art." A total of 65 scientists from 10 states in the continental United States and Hawaii, three provinces in Canada, France, Republic of Senegal, Spain, Mexico, Ivory Coast, and New South Wales (Australia) attended the workshop held at the Southeast Fisheries Center, Miami, Fla., 15-18 February 1982. Our first objective, encouraging the interchange of ideas, is well illustrated in the summaries of the Round Table Discussions and in the Glossary, which defines terms used in this volume. The majority of the workshop participants agreed that the lack of validation of age estimates and the means to accomplish the same are serious problems preventing advancements in assessing the age and growth of fishes, particularly oceanic pelagics. The alternatives relating to the validation problem were exhaustively reviewed during the Round Table Discussions and are a major highlight of this workshop. How well we accomplished our second objective, to establish the "state of the art" on age determination of oceanic pelagic fishes, will probably best be judged on the basis of these proceedings and whether future research efforts are directed at the problem areas we have identified. In order to produce high-quality papers, workshop participants served as referees for the manuscripts published in this volume. Several papers given orally at the workshop, and included in these proceedings, were summarized from full-length manuscripts, which have been submitted to or published in other scientific outlets-these papers are designated as SUMMARY PAPERS. In addition, the SUMMARY PAPER designation was also assigned to workshop papers that represented very preliminary or initial stages of research, cursory progress reports, papers that were data shy, or provide only brief reviews on general topics. Bilingual abstracts were included for all papers that required translation. We gratefully acknowledge the support of everyone involved in this workshop. Funding was provided by the Southeast Fisheries Center, and Jack C. Javech did the scientific illustrations appearing on the cover, between major sections, and in the Glossary. (PDF file contains 228 pages.)

Small Indigenous Freshwater Fish Species: their Role in Poverty Alleviation, Food Security and Conservation of Biodiversity, 23-25 February 2010, Central Inland Fisheries Research Institute, Barrackpore, Kolkata, West Bengal. Workshop report

This is the report on the workshop on “Small Indigenous Freshwater Fish Species: Their Role in Poverty Alleviation, Food Security and Conservation of Biodiversity”, organized by the International Collective in Support of Fishworkers(ICSF) in collaboration with the Inland Fisheries Society of India (IFSI). The workshop was a forum for exchange of views on the role of small indigenous freshwater fish species (SIFFS) in enhancing rural food supply and livelihood security, and in conserving biodiversity. The workshop also discussed the socioeconomic and cultural contexts for the culture and capture of SIFFS, and how to enhance access—especially for women—to better incomes, livelihoods and nutritional security, through appropriate policy spaces. This report provides a fresh focus on SIFFS, usually regarded as ‘trash’ fish. It urges scientists, researchers and decisionmakers to develop policy and legislative measures to ensure the conservation and promotion of SIFFS, both in capture- and culture-fisheries systems. This report will be useful for fishworker organizations, researchers, policymakers, fish farmers, members of civil society and anyone interested in fisheries and livelihoods. (PDF contains 86 pages)