Impact of hatchery releases on the recreational fishery for Pacific threadfin (Polydactylus sexfilis) in Hawaii

The Pacific threadfin (Polydactylus sexfilis) is considered one of the premier Hawaiian food fishes but even with catch limits, seasonal closures, and size limits, catches have declined dramatically since the 1960s. It was identified as the top candidate species for stock enhancement in Hawaii, based on the decline in stocks, high market value, and importance of the fishery. In the stock enhancement program for Pacific threadfin, over 430,000 fingerlings of various sizes were implanted with coded wire tags and released in nursery habitats along the windward coast of Oahu between 1993 and 1998. Because few Pacific threadfin were present in creel surveys conducted between 1994 and 1998, Oahu fishermen were offered a $10 reward for each threadfin that was caught (for both hatchery-reared and wild fish). A total of 1882 Pacific threadfin were recovered from the reward program between March 1998 and May 1999, including 163 hatchery-reared fish, an overall contribution of 8.7% to the fishery. Hatchery-reared fish accounted for as high as 71% of returns in the release areas. Hatchery-reared fish were recovered on average 11.5 km (SD=9.8 km) from the release site, although some had moved as far away as 42 km. Average age for recovered hatchery-reared fish was 495 days; the oldest was 1021 days. Cultured Pacific threadfin juveniles survived and recruited successfully to the recreational fishery, accounting for 10% of fishermen’s catches on the windward side of Oahu. Recruitment to the fishery was highest for the 1997 release year; few juveniles from earlier releases were observed. Presence of a few large, fully developed females in the recreational fishery suggested that hatchery-reared fish can survive, grow, and reproductively contribute to the population. Implementation of an enhancement program that is focused on juveniles and perhaps large females, as part of an integrated fishery management strategy, could speed the recovery of this fish population.

A comparative study on the hatching of common carp eggs in hapa and hatchery (model CIFE D-80)

Common carp (Cyprinus carpio) eggs were incubated to study the efficiency of hatching in hapa and hatchery. During incubation the recorded temperature was 21-28 degree C and 20-31 degree C, dissolved oxygen 6-9 ppm. and 3-5 ppm., total alkalinity 180-250 ppm. and 28-62 ppm. respectively in the hatchery (model C.I.F.E. D-80) and hapa. CO sub(2) was totally absent in the hatchery, but recorded 3-10 ppm. in the hapa. The flow of water was maintained at 1.25 l/minute/jar in the hatchery. Under the above environmental conditions the eggs hatched in 42-51 hrs. in the hatchery and 61-81 hrs. in the hapa from egg to spawn thereby establishing the hatchery to be a better hatching system for carp eggs.

Carp seed production during drought year 1987 under controlled hatchery system

The introduction of the controlled hatchery system "Model CIFE D-81" resulted in a production of 60 lakhs Indian major carp seed in the drought area of eastern Uttar Pradesh. The hatchery system provided optimum temperature, dissolved oxygen and pH for breeding and hatching and also removed the metabolites generated. The technology is simple and the success of the program attracts pisciculturists.

Fish seed production under controlled hatchery system: a cottage industry

The fish seed production in recent times has emerged as a cottage industry, with the development of controlled hatchery system. Two units of six buckets of vertical hatchery system i.e. Modern Carp Hatchery CIFE D-81 were installed in a private fish farm. 130.25 lakh spawn of Indian Major Carp (Cyprinidae) was produced during the 1988 season, with an average survival rate of 70%. The results support the viability of technology especially for the economically weaker section.

Recent advances in the hatchery production of seed of some commercial bivalves in India

The Central Marine Fisheries Research Institute has established a shellfish hatchery laboratory at its Tuticorin Research Centre with the objective of developing appropriate technology for the production of seed of commercial bivalves. A viable technology was developed for the mass production of the seed of Pinctada fucata, P. margaretifera, Crassostrea madrasensis, Perna indica, P. viridis, Anadara granosa and Meretrix meretrix. The hatchery facility and the technology, comprising brood stock conditioning, induced spawning, larval rearing and seed production are described. In the light of these developments the future outlook is appraised.

Allozyme variation in four hatchery populations of Thai pangas, Pangasius hypophthalmus in Bogra, Bangladesh

Genetic variation of four hatchery stocks of Thai pangas, Pangasius hypophthalmu [sic] of Bogra region, Bangladesh was studied from 1 January 2002 to 31 December 2003. Muscle samples were collected for allozyme analysis from four (Bhai-Bhai, Jahangir, Belal and Bhai-Bon) different hatchery populations. For allozyme electrophoresis, eight enzymes were used and 11 loci viz. Adh-1*, Est-1*, GJpdh-1*, Gpi-1*, Gpi-2*, Jdhp-1*, Ldh-1*, Ldh-2*, Mdh-1*, Mdh-2*and Pgm* were identified, of which three loci (Est-1*, Gpi-2*, G3pdh-1 and Pgm*) were polymorphic in all the four populations. The mean proportion of polymorphic loci per population and the mean proportion of heterozygous loci per individual was 36.36% and 13.33, respectively for all the population studied. The highest variability measured by the mean number of alleles per locus was 1.545 in Bhai-Bon hatchery population. Based on Nei's (1972) genetic distance, the dendrogram (UPGMA) shows that four populations have made two clusters by D-value (D=0.043). Bhai-Bhai and Jahangir hatchery populations have made cluster-I, and Belal Uddin and Bhai-Bon hatchery populations formed cluster-II. Among the four populations, BhaiBhai and Jahangir hatchery populations were differentiated from each other by the D-value of 0.013, and Belal Uddin and Bhai-Bon populations were differentiated from each other by the D-value of 0.002, which suggests that the four populations may be fallen into the local population or race.

Use of allozyme markers to determine the genetic structure of hatchery population of Thai pangas, Pangasius hypophthalmus of Jessore, Bangladesh

Genetic structure of hatchery population of Thai pangas (Pangasius hypophthalmus) of Jessore region, Bangladesh has been investigated from 1 January 2004 to 31 December 2004. Samples for this study were collected from five fish hatcheries viz. Asrom, Banchte Shekha, Chowdhury, Maola and Rezaul Haque. The enzymes were encoded by 15 gene loci: Adh-1*, Est-1*, G3pdh-2*, Gpi-1*, Gpi-2*, Idhp-1*, Idhp-2*, Ldh-1*, Ldh-2*, Mdh-1*, Mdh-2*, Pgm*, Sdh-1*, Sdh-2* and Sod*. Among them four (Est-1*, G3pdh-2*, Gpi-2*and Pgm*) were found to be polymorphic in different populations but only Gpi-2* was polymorphic in all the sampled populations. The mean proportion of polymorphic loci per population was the highest (26.7%) in Banchte Shekha hatchery while the mean proportion of heterozygous loci was 13.33% per individual in Banchte Shekha and Maola hatcheries. The UPGMA dendrogram of Nei's (1972) genetic distances indicated a relationship between the genetic distance and geographical difference. High genetic variability in stocks of Thai pangas was observed in the Banchte Shekha and Maola hatcheries and less variability was found in the other three hatcheries.

Allozyme and morphological variation in four hatchery stocks of Thai pangas, Pangasius hypophthalmus in Mymensingh, Bangladesh

Genetic and morphological characters of four hatchery population (Shambhuganj, Brahmaputra, Anudan and Bhai-Bhai) of Thai pangas, Pangasius hypophthalmus in Mymensingh region of Bangladesh was studied using morphological characters and allozyme markers from 29 November 2001 to 29 November 2002. A total of 14 morphometric and 6 meristic characters were verified, among which 3 morphometric (BDA, PELFL and HW) and 2 meristic characters (AFR, CFR) of Anudan hatchery population were found to be significantly higher (p>0.001) than those of the other three hatchery populations. Brahmaputra hatchery population was also significantly higher in two meristic characters (PCFR and CFR). For allozyme electrophoresis nine enzyme markers were used viz.: Esr-1*, G3pdh-2*, Gpi-1*, Gpi-2*, Ldh-1*, Ldh-2*, Mdh-1*, Mdh-2* and Pgm* where three loci (Esr-1*, Gpi-2* and Pgm*) were polymorphic (p>0.95) in Anudan and Brahmaputra hatchery populations. The mean proportion of polymorphic loci per population was higher (33.3%) in Brahmaputra and Anudan hatchery populations. Also the expected heterozygosity levels were 0.149 and 0.177 in Brahmaputra and Anudan hatchery populations, respectively. Based on Nei's (1972) genetic distances, the UPGMA dendrogram grouped the populations into two clusters. The Brahmaputra and Anudan populations are in one group; Shambhuganj, and Bhai-Bhai populations are in the second group. High genetic variation in Thai pangas was observed in the Brahmaputra and Anudan hatchery populations and less variation in the other two hatchery populations.

Cumulative inbreeding rate in hatchery-reared indian major carps of Karnataka and Maharashtra states

The state fisheries department hatcheries are the major suppliers of seed to the farmers in Karnataka and Maharashtra. The brood stocks of these hatcheries are genetically closed units. In the present study, effective population size and cumulative inbreeding rates were estimated. The cumulative inbreeding rates ranged from 2.69 to 13.75, 8.63 to 15.21 and 3.02 to 5.88 per cent for catla, mrigal and rohu, respectively, in Karnataka state hatcheries. In Maharashtra, the cumulative inbreeding rates for catla ranged from 7.81 to 39.34 per cent and it was 5.84 to 14.09 and 2.46 to 10.20 per cent for mrigal and rohu, respectively. To estimate the inbreeding rates in future generations, predictive models were developed using linear regression, and polynomial and power equations separately for each hatchery. Their multiple correlation and standard errors suggested that simple linear regression can predict the future inbreeding rate efficiently.

Effects of water movement and aeration system on the survival and growth of hatchery bred sugpo (Penaeus monodon Fabricius) in earthen nursery ponds

An experiment was conducted to determine the effects of water movement and airlift aeration on the survival and growth of P. monodon fry reared from P sub(4)P sub(5) to P sub(32)P sub(33) in earthen brackishwater ponds. The high survival rates obtained justify the need for aeration when using the earliest stages of fry (P sub(4)P sub(5)) at higher stocking densities. For older stages regardless of source and at lower stocking densities, nursery operations based on traditional methods could also achieve better survival rates.

Growth and survival rates of hatchery-produced and wild milkfish fry grown to fingerling size in earthen nursery ponds

Growth and survival rates of hatchery-produced and wild milkfish (Chanos chanos ) fry grown to fingerling size were compared. Data show no significant difference between the 2 fry. At a recommended stocking density of 30 fry/m super(2), hatchery-produced milkfish fry could attain fingerling size of almost 2g with a survival of 68%. The study indicates that hatchery-produced fry/fingerlings can equal the culture performance of the wild fry. Comparative performance of hatchery-bred and wild fry should encourage intensified research on milkfish broodstock development and refinement of induced spawning methods.

Study on fish hatchery and nurseries in Mymensingh, Bangladesh

In generally, fish hatchery and nursery owners having both hatchery and nursery facilities were financially stronger, well-educated and well-trained than only nursery ponds owners in Mymensingh aquaculture region. On the other hand, only nursery pond owners were more experienced in fish seed business than only hatchery owners. Most of the owners were satisfied with existing communication facilities. Lack of technical knowledge was one of the major constraints which could be solved by ensuring proper training. This business can be made more profitable providing loan to poor farmers and improving law and order situation.