Wild Broodstock Research Articles

Evaluation of incubation temperatures on DNA damages of the Caspian trout (Salmo trutta caspius Kessler, 1877) single cells through developmental stages by Comet assay

Caspian trout (Salmo trutta caspius Kessler, 1877) is an endemic migratory subspecies in the Caspian Sea, possessing ecologic-economic and biodiversity greatly value. Among habitat factors, temperature and its possible effects on the Caspian trout genome were considered in this research. During Embryonic developmental stages (fertilization–hatching), genomic alterations of single cells were assessed by Comet assay technique in three thermal treatments (4, 8, 12oC). After artificial propagation of wild broodstocks, the batches of eggs (No. 500), were transferred to well equipped incubators with constant temperatures, water recycling systems by REDD(spawning area of trout)water, 3 stages water filtration (Si+Active Coal+Zeolite), UV-C application on effluent of each incubator and DO – pH – temperature digital controllers in 3 replicates. Samples were collected from normal (8°C), cold (4°C) and warm (12°C) treatments on eyed egg, alevin and larval stages. Single Cell Gel Electrophoresis technique were applied on samples for evaluation of Comet Tail length (TL), DNA in tail (DT) and Tail Moment (TM) indexes (CometScore software ©2013 TriTek Corp) as DNA damage markers. Significant difference between thermal treatments (P<0.05) and comparison between mean values of comet TL index indicated 85.19 ±9.2 , 9.88 ±2.3 and 256.54±14.6 for 4, 8 and 12°C treatments, respectively. DT mean values measured as 18.07±6.3, 9.72±1.9 and 31.47±2.8 and then TM mean values measured as 15.27± 4.1, 1.21±0.2 and 95.25±8.6 for 4, 8, and 12°C treatments respectively. Warm (12°C) treatments demonstrated greater DNA damages in comparison to the others. TM explained better information in comparison with TL & DT in all analyzed samples. In conclusion, temperatures out of optimal thermal conditions could significantly affect Caspian trout genome which could be subject of management considerations pertaining to Caspian trout stocks rehabilitation and captive rearing strategies.

Reduced growth performance of Black Tiger shrimp (Penaeus monodon) infected with infectious hypodermal and hematopoietic necrosis virus

In Australia, Infectious hypodermal and hematopoietic necrosis virus (IHHNV) occurs endemically in Black tiger shrimp (Penaeus monodon) and has been detected at high prevalence in farmed shrimp. Here we examined the role of high IHHNV infection prevalence and loads in reduced growth and survival in P. monodon reared under commercial conditions in 0.16 ha research ponds. TaqMan real-time quantitative (q)PCR testing of wild broodstock from the East Coast of Queensland identified lower and higher IHHNV infection loads among females used to generate 2 cohorts of progeny. Tracking of IHHNV loads in eggs and juveniles sampled progressively over grow-out identified these to be substantially higher and to increase more rapidly in 2 ponds stocked with a batch of postlarvae (PL) pooled from 3 females with high-level IHHNV infection at the time they spawned compared to 2 neighbouring ponds stocked with PL pooled from 4 females, of which only 1 possessed IHHNV at a relatively high load. From 120 days of culture (DOC) onwards, the growth performance in the IHHNV-high ponds began to progressively reduce compared to that in the IHHNV-low ponds. When harvested over 2 weeks starting at 155 DOC, the averaged harvest yield of the 2 IHHNV-high ponds was the equivalent of 3.72 t/ha lower than the 2 IHHNV-low ponds, and estimated survival was also markedly lower (79.5–84.5% compared to 95.9–99.8%). As real-time qPCR testing identified no involvement of either Gill-associated virus (GAV) or Yellow head virus genotype 7 (YHV7), other viruses known to cause such production losses in Australia, the data support a sustained high IHHNV infection burden as the primary contributor to the reduced growth and survival. Using a basic extrapolation of yield, stocking low-level IHHNV PL has resulted in an increase of farm gate value of $67,000 per hectare compared to stocking high-level IHHNV PL. Among other problems such as severe shell deformities that acute IHHNV infection has recently been identified to cause in locally-farmed P. monodon, the potential impacts on growth and survival identified here reinforce the value in screening-based selection of IHHNV-free/low broodstock for use in hatcheries and in breeding programs employing specific pathogen-free stocks, and strategies to select for IHHNV resistance/tolerance.

Isolation and expression analysis of Bystin 1 transcript and protein during ovarian development of the giant tiger shrimp Penaeus monodon.

The full-length cDNA of bystin isoform 1 (PmBys1) of the giant tiger shrimp Penaeus monodon was characterized. It was 1553 bp in length containing an ORF of 1365 bp corresponding to a polypeptide of 454 amino acids. The level of PmBys1 mRNA in ovaries was greater than that in other tissues of females and in testes of males in both juveniles and wild broodstock (P < .05). In non-ablated wild female broodstock, PmBys1 mRNA significantly and progressively increased in ovaries from stage I of development, peaking at stage IV (P < .05). Its level in stages I-IV of eyestalk-ablated broodstock was greater than that in non-ablated broodstock (P < .05). Injection of exogenous serotonin (50 μg/g body weight) into 18-month-old shrimp resulted in a significantly increase of ovarian PmBys1 mRNA at 6-48 h post injection (hpi) (P < .05). PmBys1 protein (52 kDa) was found in ovarian stages I-V of non-ablated wild broodstock and II-IV of ablated wild broodstock, respectively. Along with the 52 kDa band, immunoreactive bands of 50 and 43 kDa were also observed in ovarian stages II-IV of both non-ablated and ablated broodstock and in ovaries of post-spawning broodstock. The 43 KDa band was not observed in ovarian stage I of wild female broodstock or in premature juveniles. PmBys1 protein was localized in the ooplasm of previtellogenic oocytes, nucleo-cytoplasmic compartments of vitellogenic oocytes and cortical rods of mature oocytes in wild broodstock. The results implied a possible role for PmBys1 during ovarian development in P. monodon.

Assessment of Short‐Term Mortality of Wild‐Caught Female Walleye Broodstock

AbstractThe collection of Walleye Sander vitreus eggs to meet stocking needs is an essential part of Walleye management for many state and provincial agencies. The stress of capture, holding, and stripping gametes from wild broodstock can potentially lead to Walleye mortality. In waters &lt; 1,200 ha, high levels of mortality could alter population size structure and affect angler success, future egg collections, and survival of stocked Walleyes. We quantified short‐term (i.e., 5 d) mortality of female Walleyes during artificial spawning operations during 2015 to 2017 in four eastern South Dakota natural lakes (Swan Lake in 2015, Long Lake in 2016, and Antelope Lake and Reid Lake in 2017). Each year 25 female Walleyes were stripped of their eggs and 25 additional female Walleyes were included as reference fish. No Walleyes died in 2015, four fish that were stripped of eggs at Long Lake died in 2016, and one stripped of eggs at Reid Lake died in 2017. Overall short‐term mortality was low (5 of 73 fish, 6.8%) during the study. No reference fish expired during the 3 years. Contusions were apparent on ovaries of both egg‐stripped and reference fish. We believe that if fisheries personnel follow standard artificial spawning procedures for Walleye the amount of mortality will be low and should not impact populations of mature female Walleyes.

Prevalence, diversity and co-occurrence of the white spot syndrome virus, monodon baculovirus and Penaeus stylirostris densovirus in wild populations of Penaeus monodon in the Philippines

The farming of the black tiger shrimp Penaeus monodon in the Philippines relies on wild broodstock. PCR was thus used to determine the prevalence of white spot syndrome virus (WSSV), monodon baculovirus (MBV) and Penaeus stylirostris densovirus (PstDV) in a total of 178 shrimp from 6 geographically disparate locations where broodstock are captured for use in hatcheries. PCR amplicons were also sequenced to identify phylogenetic relationships of the virus haplotypes detected. Shrimp from southeastern Luzon (Camarines Norte) had the highest prevalence of each of the 3 viruses and were frequently co-infected with 2 or more viruses. No viruses were detected in shrimp from northwestern Luzon (Pangasinan). MBV was most prevalent and PstDV strains displayed the most genetic diversity. WSSV was detected at 3 sites, and a VP28 gene sequence examined was invariant and consistent with strains found in many countries, including Thailand, China, Japan, Korea, Indonesia, Iran, Brazil and Mexico. WSSV open reading frame 94 gene sequence analysis identified location-specific repeat types. MBV sequences were dissimilar to haplotypes detected in India. PstDV sequences were diverse and included 2 lineages detected either in Australia or in the United States, Ecuador, Taiwan, China and Vietnam. The PCR data confirmed that WSSV, MBV and PstDV are endemic in P. monodon in the Philippines but that populations at some locations might remain free of infection.

Differences in nutrient content of eggs and larvae as indicators for improvement of broodstock nutrition in walleye (Sander vitreus) production

The aim of this study was to increase our knowledge about the nutritional needs of walleye (Sander vitreus (Mitchill, 1818)) broodstock. Two dietary treatments were tested: the first consisted of frozen Atlantic mackerel (Scomber scombrus L., 1758) pieces with a supplement of experimental dry pellets and the second consisted of frozen Atlantic mackerel pieces with a supplement of commercial trout pellets. Hatching success was highest in eggs from the wild broodstock. Eggs and larvae from wild fish were characterized by the highest levels of linoleic (LOA; 18:2 n–6) and linolenic (LNA; 18:3 n–3) fatty acids in the neutral lipids. They had the lowest level of docosahexaenoic acid (DHA) in both neutral and polar lipids. The results suggest the importance of the amino acids leucine, lysine, methionine, and serine for better egg survival. Vitamin A1content was similar in eggs from wild fish and the younger broodstock from both treatment groups, but was 10 times lower in eggs from older broodstock. Vitamin A2was highest in eggs from wild fish. Our results showed that neither of the two diets really resulted in egg or larval quality that were comparable with that of wild fish.

REPRODUCTION PERFORMANCE OF WILD BROODSTOCK CORAL TROUT (Plectropomus leopardus)

Coral trout is an important export commodity in many countries in southeast Asia. In Indonesia, the export of grouper currently relies on capture fisheries. To ensure sustainability of the wild catch as well as to develope mariculture, we need to better understand the performance of wild broodstock.

Use of lumpfish for sea‐lice control in salmon farming: challenges and opportunities

AbstractEfficient sea‐lice control remains one of the most important challenges for the salmon farming industry. The use of wrasse (Labridae) as cleaner fish offers an alternative to medicines for sea‐lice control, but wrasse tend to become inactive in winter. Lumpfish (Cyclopterus lumpus) continue to feed on sea‐lice at low temperatures, and commercial production has escalated from thousands of fish in 2010 to well over 30 million juveniles deployed in 2016. However, production still relies on the capture of wild broodstock, which may not be sustainable. To meet global industry needs, lumpfish production needs to increase to reach c. 50 million fish annually and this can only come from aquaculture. We review current production methods and the use of lumpfish in sea cages and identify some of the main challenges and bottlenecks facing lumpfish intensification. Our gap analysis indicates that the areas in most need of research include better control of maturation for year‐round production; formulation of appropriate diets; artificial selection of elite lines with desirable traits; and development of vaccines for certified, disease‐free juvenile production. The welfare of farmed lumpfish also needs to be better quantified, and more information is needed on optimal densities and tank design. Finally, the risk of farmed lumpfish escaping from net pens needs to be critically assessed, and we argue that it might be beneficial to recover cleaner fish from salmon cages after the production cycle, perhaps using them as broodstock, for export to the Asian food markets or for the production of animal feeds.

Are antipredator behaviours of hatchery Salmo salar juveniles similar to wild juveniles?

This study explores how antipredator behaviour of juvenile Atlantic salmon Salmo salar developed during conventional hatchery rearing of eggs from wild brood stock, compared with the behaviour of wild-caught juveniles from the same population. Juveniles aged 1+ years were tested in two unfamiliar environments; in one S. salar were presented with simulated predator attacks and in the other they were given the opportunity to explore an open-field arena. No difference was found in their spontaneous escape responses or ventilation rate (reflex responses) after simulated predator attacks. Hatchery-reared juveniles were more risk-prone in their behaviours than wild-caught individuals. Hatchery juveniles stayed less time in association with shelter. In the open-field arena, hatchery juveniles were more active than wild juveniles. Hatchery juveniles were also immobile for less time and spent a shorter amount of time than wild juveniles in the fringe of the open-field arena. Salmo salar size had no effect on the observed behaviour. Overall, this study provides empirical evidence that one generation of hatchery rearing does not change reflex responses associated with threats, whereas antipredator behaviour, typically associated with prior experience, was less developed in hatchery-reared than in wild individuals.

Abdominal segment deformity syndrome (asds) and fused body segment deformity (fbsd) in cultured Penaeus indicus

The abdominal segment deformity disease (ASDD) is a new shrimp disease reported only in cultured Penaeus vannamei in Thailand. Shrimp with ASDD have deformed abdominal segment, jagged gut line and bumpy surfaces. Similar signs were observed in cultured P. indicus in the Philippines. However, aside from the signs described for ASDD, some P. indicus showing abdominal segment deformity syndrome (ASDS) had more severe deformities up to the extent that the number of body segments was reduced due to fusion. Shrimp with fused body segment deformity (FBSD) had four instead of five pairs of legs. To account the prevalence of the deformities in P. indicus, shrimp were classified into grossly normal shrimp (NS), shrimp with abdominal segment deformity syndrome (ASDS) and shrimp with fused segments (FBSD). Out of the shrimp sampled, 83.4±5.4% was NS, 10.9±6.2% was ASDS and 5.7±3.0% was FBSD. Morphometric characteristics of the shrimp were measured. There was no significant difference in body weight (BW) among male and female NS, ASDS and FBSD. In both sexes, total length (TL) of FBSD was significantly shorter compared to NS and ASDS. Shrimp samples were also screened to be negative for known infectious viral diseases including white spot syndrome virus (WSSV), infectious hypodermal and haematopoietic necrosis virus (IHHNV), infectious myonecrosis virus (IMNV), P. vannamei nodavirus (PvNV), Macrobrachium rosenbergii nodavirus (MrNV) and Taura syndrome virus (TSV). Occurrence of ASDS and FBSD in post-larvae (PL) produced from captive and wild spawners were also determined. Based on a tank experiment, no significant difference was detected between the percentages of ASDS in PL produced from wild or captive spawners but FBSD was only noted in PL produced from the latter. Deformities generally did not affect the size of P. indicus except for the reduced length of shrimp with FBSD which when coupled with missing pleopods could lead to major economic loss for shrimp farmers if not addressed properly. Statement of relevanceShrimp is a major aquaculture commodity in the world but the industry has always struggled because of disease outbreaks. Abdominal segment deformity disease (ASDD) is a Penaeus vannamei disease recently reported. Similar pathological signs were observed in tank and pond cultured Penaeus indicus in the Philippines. This paper provided the first information on the abdominal segment deformity syndrome and fused body segment deformity in P. indicus. Data on the prevalence, morphometric characteristics and influence of sourced (captive or wild broodstock) were presented in this study.

A study on incubation of Brown Trout (Salmo trutta sp.) eggs and feeding of fry

In this study, spawning, incubation success or survival rate of brown trout and initial feeding of fry were investigated. The wild broodstock in this study were caught in Akcay river in Sapanca. In July 2008, 7 female and 1 male fish with a body weight between 300-350 g were brought to the Istanbul University, Faculty of Fisheries Sapanca Inland Waters Research Center (Adapazari, Turkey). These fish were kept in fiberglass adaptation tanks and were fed fresh rainbow trout meat. During this period, fish were fed with 9 mm pelleted feed. In June 2009, when fish had reached an average weight of 2500-3000 g, the first biometric measurements on the fish were performed. In early March 2010, about 3000 eggs were stripped from one female broodstock and sperms from the male brown trout. After the fertilization, the eggs were placed in horizontal incubators. The eye development started on the 21st day and hatching began on the 30th day. Hatching was found to be approximately 74%. When fish run out of their yolk sac, fry were divided into three groups of 600 individuals per tank and kept under same incubation conditions. Fry were fed feeds such as Artemia sp., fresh lamb liver, microdiets (300, 500 and 700µm) and extruded pellet feed (1mm). For the first group, fry were started on Artemia for seven weeks and continued on microdiets and extruded pelleted feed. For the second group, fry were started on microdiets and continued on extruded pellet feed. For the third group, fry were started on fresh lamp liver for a month and continued as the other groups. Fry were fed multiple times a day to satiation. Water used in the experimental tanks was from the research center. Average parameters recorded included water temperature of 11.5oC, pH of 7.86 and DO of 9.6 mg/L. At the end of the experimental period, the number of dead fry were 77, 104 and 123 in the first, second and third groups respectively. In conclusion, the present study indicated that the first generation eggs incubation from wild broodstock brown trout adapted to culture conditions successfully. However, further studies on the first feeding at the fry stage are encouraged. Keywords: Brown trout, broodstock culture, egg incubation, survival, fry nutrition

Larval connectivity of pearl oyster through biophysical modelling; evidence of food limitation and broodstock effect

The black-lip pearl oyster (Pinctada margaritifera) is cultured extensively to produce black pearls, especially in French Polynesia atoll lagoons. This aquaculture relies on spat collection, a process that experiences spatial and temporal variability and needs to be optimized by understanding which factors influence recruitment. Here, we investigate the sensitivity of P. margaritifera larval dispersal to both physical and biological factors in the lagoon of Ahe atoll. Coupling a validated 3D larval dispersal model, a bioenergetics larval growth model following the Dynamic Energy Budget (DEB) theory, and a population dynamics model, the variability of lagoon-scale connectivity patterns and recruitment potential is investigated. The relative contribution of reared and wild broodstock to the lagoon-scale recruitment potential is also investigated. Sensitivity analyses pointed out the major effect of the broodstock population structure as well as the sensitivity to larval mortality rate and inter-individual growth variability to larval supply and to the subsequent settlement potential. The application of the growth model clarifies how trophic conditions determine the larval supply and connectivity patterns. These results provide new cues to understand the dynamics of bottom-dwelling populations in atoll lagoons, their recruitment, and discuss how to take advantage of these findings and numerical models for pearl oyster management.

The case of the endangered Kootenai River white sturgeon (Acipenser transmontanus) highlights the importance of post-release genetic monitoring in captive and supportive breeding programs

The success of captive and supportive breeding programs is often determined by abundance criteria but it is also necessary to consider genetic characteristics of reintroduced or supplemented populations as genetic diversity loss can reduce population viability. Genetic analysis of the parent pools is often used to determine whether captive or supportive breeding programs conserve adequate levels of genetic diversity and maximize the effective population size (Ne). This practice assumes that released cohorts reflect the genetic characteristics of parents. Here we provide a case study of how post-release mortality can alter the genetic composition of released cohorts in a supportive breeding program for an endangered population of white sturgeon. Data from ongoing genetic monitoring of wild broodstock in the Kootenai River white sturgeon conservation aquaculture program are combined with multi-year post-release abundance monitoring of captive bred juveniles to reveal high variability in recapture among families. We found that genetic monitoring of broodstock used in supportive breeding overestimates genetic diversity conservation in most year classes due to differential post-release mortality among families. Ne was reduced in most year classes when post-release mortality was considered due to reduced parental representation in released cohorts. Although rarely performed, our results indicate that post-release genetic monitoring is necessary to accurately characterize the genetic composition of released cohorts altered by post-release mortality and should be considered when designing a captive or supportive breeding program.

PRODUCTION OF FUNCTIONAL MALE BROODSTOCK OF CORAL TROUT GROUPER (Plectropomus leopardus)

Fertilization rate of the first generation of coral trout grouper, Plectropomus leopardus from wild broodstock in cultured tank was relatively low of 10-35%. Based on gonad histology analysis of 30 samples, only one male was found in early stage maturation. Therefore, it is needed to increase functional male production to ensure an increase level of egg fertilization. The experiment was conducted for 9 months using coral trout broodstock, from wild stock as control and selected F1 from culture as treatment. Broodstocks were reared in three tanks, each was 100 m3 in volume with 54 fishes/tank. All selected cultured fish (F1) in tank C were implanted with 17a-MT hormone at 50 mg/kg of body weight every month for 3 consecutive months. Wild stock fish in tank A and selected cultured fish (F1) in tank B were not implant as controls. The result showed that the number of male increased 6 times in implanted by 17a-MT hormone compared to fish without implant only increased 2 times. Therefore, eggs fertilization and hatching rate were significantly increased by implanting F1 broodstocks with hormone17a-MT. Keywords: Functional male, broodstock, Coral trout (Plectropomus leopardus)

A Synthesis of Findings from an Integrated Hatchery Program after Three Generations of Spawning in the Natural Environment

AbstractThe Cle Elum Supplementation and Research Facility in the Yakima River basin, Washington, is an integrated spring Chinook Salmon Oncorhynchus tshawytscha hatchery program designed to test whether artificial propagation can increase natural production and harvest opportunities while keeping ecological and genetic impacts within acceptable limits. Only natural‐origin (naturally spawned) fish are used for hatchery broodstock. Spawning, incubation, and early rearing occur at a central facility; presmolts are transferred for final rearing, acclimation, and volitional release at sites adjacent to natural spawning areas, where returning adults can spawn with natural‐origin fish. The first wild broodstock were collected in 1997, and age‐4 adults have returned to the Yakima River since 2001. An unsupplemented population in the adjacent Naches River watershed provides a reference for evaluating environmental influences. The program has been comprehensively monitored from its inception. A synthesis of findings, many already published, is as follows: supplementation increased the harvest, redd counts, and spatial distribution of spawners; natural‐origin returns were maintained; straying to nontarget systems was negligible; natural‐origin females had slightly higher breeding success (production of surviving fry) in an artificial spawning channel, while the behavior and breeding success of natural‐ and hatchery‐origin males were similar; hatchery‐origin fish showed differences in morphometric and life history traits; high rates of hatchery age‐2 (minijack) production were reported, but the observed proportions of out‐migrating juvenile and adult (ages 4 and 5) returning males were comparable for hatchery‐ and natural‐origin fish; hatchery smolts did not affect the levels of pathogens in natural smolts; and the ecological interactions attributed to the program were within adopted guidelines. Continued study is required to assess the long‐term impacts on natural production and productivity.

Differential expression of X-box binding protein 1 during ovarian development and association between its SNP and growth-related parameters of the giant tiger shrimp Penaeus monodon

Abstract The full-length cDNA of X-box binding protein 1 ( PmXbp1 ) in the giant tiger shrimp, Penaeus monodon was identified. It was 1762 bp in length containing an ORF of 855 bp corresponding to 284 amino acids. The expression level of PmXbp1 in different ovarian stages of wild intact broodstock was comparable but greater than that of cultured juveniles ( P PmXbp1 in stages III (late vitellogenic) and IV (mature) ovaries of wild P. monodon broodstock ( P PmXbp1 in ovaries of domesticated 18-month-old broodstock at 24 hpi ( P PmXbp1 (185 bp) were examined in domesticated 3-month-old juveniles (average body weight and total length = 12.32 ± 5.13 g and 11.30 ± 1.58 cm, N = 162) by single-strand conformational polymorphism (SSCP) analysis. Association between SSCP patterns of PmXbp1 and growth-related parameters was found where the average body weight (15.07 ± 5.04, N = 44) of juveniles carrying pattern A (corresponding to a T/T 349 SNP) was significantly greater than that (11.37 ± 4.80, N = 116) of juveniles carrying pattern B (corresponding to a T/C 349 SNP). The relative expression levels of PmXbp1 in the hepatopancreas of juveniles carrying different SSCP/SNP genotypes were significantly different (A P PmXbp1 in shrimp exhibiting a greater growth performance (22.08 ± 2.97 g and 13.60 ± 0.56 cm; N = 11) was significantly lower than that with a lesser growth performance (5.00 ± 0.89 g and 8.60 ± 0.98 cm; N = 8) ( P PmXbp1 seems to play an important role in reproduction and growth of P. monodon . Statement of relevance In aquaculture, the primary goal of genetic selection is the growth improvement of economically important species. Molecular markers that allow for selection of juveniles and broodstock with a high breeding value for reproductive maturation and/or growth rates are useful for the shrimp industry. Information on correlation between genotypic and phenotypic variations in penaeid shrimp is rather limited. Identification of molecular markers linked with growth/reproduction or those regulating the growth/reproduction mechanisms can be applied to improve artificial selection processes of P. monodon . To assess the possible biological roles of X-box binding protein 1 in reproduction and growth of P. monodon , the PmXbp1 cDNA sequence was characterized. Expression patterns of PmXbp1 during ovarian development in wild P. monodon broodstock were examined. Effects of eyestalk ablation (wild broodstock) and serotonin induction (domesticated broodstock) on expression levels of ovarian PmXbp1 were examined. In addition, analysis of relationships between SNP detected by SSCP and DNA sequencing and expression levels of PmXbp1 , and growth traits in juvenile shrimp was examined.

Induction of vitellogenesis and reproductive maturation in tiger shrimp, Penaeus monodon by 17ß-estradiol and 17α-hydroxyprogesterone: in vivo and in vitro studies

Ovarian explants of Penaeus monodon taken from different developmental stages (immature (transparent), immature (yellow), and vitellogenic (green)) were incubated for 24 h in medium 199 supplemented with either E2 or 17α-OHP. Exogenous E2 stimulate Vg mRNA synthesis in the immature (yellow) ovary only, while 17α-OHP stimulates mRNA synthesis only in vitellogenic ovary. However, in vitro treatment with both hormones resulted in significant increase in oocytes diameter at higher doses. In vivo assays were carried out by administrating these hormones alone or along with eyestalk ablation at a dose of 9 × 10−5 M per individual. After 7 days, significantly higher gonadosomatic index resulted in E2 and 17α-OHP treatment along with eyestalk ablation. Further, Vg mRNA transcript level was significantly higher in the group received both 17α-OHP and eyestalk ablation. Progesterone and estradiol receptors were characterized using western blotting. Discrete immunoreactive bands of estrogen Receptor (ER) (~78 kDa) and progesterone Receptor (PR) (~70 kDa) were detected in the ovary of wild brood stock. These findings suggest a reproductive role for these steroidal hormones, which could possibly be used in the induction of maturation and spawning in captive female penaeids.

Quality of Blue swimming crab Portunus pelagicus Larvae from Domesticated Broodstock

Blue swimming crab (Portunus pelagicus) is the important world fishery resource, but the crab larval rearing faces high mortality problem. The aim of the research was to compare survival and growth rate of larvae resulted from wild and domesticated broodstock blue swimming crab. Domesticated and wild broodstock were used to produce larvae. Domesticated broodstock was selected from repeated reared crab until third generation. Selection of the broodstock mainly based on the survival and growth rate. The wild broodstock was collected from Makassar Strait Sea. Larvae from the two sources of broodstock were reared in the conical tanks with density of 50 zoeas per liter. After reaching megalopa phase, then, the larvae were transfered into concrete tank completed with shelter and it were reared until crab phase. Crab phase was reared for 18 days, then these seed were released into the brackishwater pond for further domestication step. Larva from zoea to crab were fed with rotifer, artemia, fresh small shrimp and diet. The result showed that domesticated broodstock produced higher survival rate (P<0.05) larvae, faster larval stage changes (P<0.01) and uniform larval growth compared to the larvae from wild broodstock. It is clearly shown, the use of domesticated broodstock of blue swimming crab produced better larva quality and quantity than the wild broodstoock crab. Keywords : blue swimming crab, larvae, domestication, broodstock selection, faster growth

Productivity benefits of selectively breeding Black Tiger shrimp (Penaeus monodon) in Australia

Advances in the domestication and selective breeding of Australian Black Tiger shrimp, Penaeus monodon, opens the opportunity for world producers to reconsider the benefits of farming this species. Just over a decade ago this species was the world's most farmed shrimp species, however, difficulty in its domestication, in part, led to the widespread establishment of Penaeus vannamei (Pacific White shrimp) as the most farmed shrimp species in the world. This study empirically evaluates the productivity benefits of commercially domesticating P. monodon against production from wild broodstock of the same species. The evaluation compared the relative production from commercial ponds stocked with the progeny of wild P. monodon broodstock and ponds stocked with the progeny of domesticated stocks. The production data were from 164 ponds of domesticated stocks and 30 ponds of wild stocks, collected over 4 years (2009–2013) from two separate farm sites of the same Australian shrimp farming company. The wild stocks were sourced from the east coast of Australia. The results suggested that the productivity of the selectively bred stocks was 39% greater compared with production from wild stocks given equivalent amounts of feed and other inputs. Furthermore, productivity was additionally enhanced depending on the choice of feeds and whether stocking took place in September rather than later in the year (i.e. in early spring rather than late spring/early summer in the Southern hemisphere). This suggests that there is significant potential to further enhance the productivity of P. monodon farms via integrating advances in domestication, feeds and management practices.

Testing and validating a modified CTAB DNA extraction method to enable molecular parentage analysis of fertilized eggs and larvae of an emerging South African aquaculture species, the dusky kob Argyrosomus japonicus.

This study describes the successful implementation of a modified cetyltrimethyl ammonium bromide (CTAB) protocol to isolate genomic DNA and amplify 14 microsatellite markers from fertilized eggs and larvae of an emerging South African farmed marine fish species, the dusky kob Argyrosomus japonicus. To test and validate the efficiency of this method, genetic data were utilized to resolve parentage and kinship of first-generation (F1) offspring produced in mass-spawning events of wild broodstock fish in a commercial hatchery.