New Aquaculture Species Research Articles

Simulated Transport of Silver Therapon (Leiopotherapon plumbeus) Fingerlings at Different Durations and Loading Densities: Effects on Survival and Water Quality

The silver therapon, Leiopotherapon plumbeus, is a new species for aquaculture. However, information on the optimal conditions for the transport of this species for grow-out culture needs to be established to avoid stress and unnecessary mortalities. This study examined the effects of duration of transport and loading density on survival and water quality during simulated transport of silver therapon. Hatchery-produced fingerlings [1.30 ± 0.34 g body weight (BW); 44.30 ± 3.77 mm total length (TL)] were held in double-layered oxygenated plastic bags at three transport durations (6 h, 9 h, and 12 h) and densities (40 fish bag-1, 80 fish bag-1, and 120 fish bag-1) in triplicates. Mean survival rates were not significantly affected by both duration of transport (P = 0.321) and loading density (P = 0.345). However, a highly significant effect of duration of transport on dissolved oxygen (DO) and pH (P = 0.000), and a significant effect on Total Ammonia Nitrogen (TAN; P = 0.039) and total bacterial count (TBC; P = 0.034) were evident. Similarly, water quality parameters were significantly influenced by loading density (P = 0.000), with lower DO and pH levels, and higher TAN and TBC recorded at 120 fish bag-1 density. Since a very high survival rate (> 99%) is achieved at the highest loading density of 120 fish bag-1 up to 12 h transport, this density can be recommended to transport silver therapon fingerlings. Chemical treatments using either salt, methylene blue, or tropical almond leaf extract in transport water may be used to reduce the high bacterial count during transport.

Generational breeding gains in a new species for aquaculture, the Australasian snapper (Chrysophrys auratus)

Selective breeding for improved trait performance is a promising approach for developing new species for food production. Globally, a shortage of livestock species presents a significant bottleneck, and this is particularly pronounced for the aquaculture sector. In New Zealand, the Australasian snapper (Chrysophrys auratus) is a potential candidate for aquaculture, and a breeding programme was started in 2004. Here we assess the performance of the most recent F4 cohort in terms of growth and survival against 1) previous generations and 2) unselected offspring from wild broodstock over the first 6 months. First, we detected generational gains over the entirety of the breeding programme in growth, averaging 11.4% for length and 81.1% for weight over 3 years, and detected a strong seasonal Specific Growth Rate (SGR) increase during summer and a general decrease of growth with age. Second, when growing the F4 and F1 cohort side by side, we found a consistent pattern of superior performance, less growth heterogeneity, and a higher condition factor within the F4 population. Notably, these data revealed breeding gains of 4.9% in survival, 10.5% in length and 41.4% in weight for F4 snapper over the first 6 months from hatching. Together these results indicate that domestication gains and genetic improvement can strengthen the potential of snapper as a candidate to diversify and grow aquaculture in New Zealand.

Characterization of Host-Associated Microbiota and Isolation of Antagonistic Bacteria from Greater Amberjack (Seriola dumerili, Risso, 1810) Larvae.

Greater amberjack (Seriola dumerili) is a new species in marine aquaculture with high mortalities at the larval stages. The microbiota of amberjack larvae was analyzed using 16S rDNA sequencing in two groups, one added copepod nauplii (Acartia tonsa) in the diet, and one without copepods (control). In addition, antagonistic bacteria were isolated from amberjack larvae and live food cultures. Proteobacteria was the most abundant phylum followed by Bacteroidota in amberjack larvae. The composition and diversity of the microbiota were influenced by age, but not by diet. Microbial community richness and diversity significantly increased over time. Rhodobacteraceae was the most dominant family followed by Vibrionaceae, which showed the highest relative abundance in larvae from the control group 31 days after hatching. Alcaligenes and Thalassobius genera exhibited a significantly higher relative abundance in the copepod group. Sixty-two antagonistic bacterial strains were isolated and screened for their ability to inhibit four fish pathogens (Aeromonas veronii, Vibrio harveyi, V. anguillarum, V. alginolyticus) using a double-layer test. Phaeobacter gallaeciensis, Phaeobacter sp., Ruegeria sp., and Rhodobacter sp. isolated from larvae and Artemia sp. inhibited the fish pathogens. These antagonistic bacteria could be used as host-derived probiotics to improve the growth and survival of the greater amberjack larvae.

The Optimum Lipid Level for the Juvenile Redclaw Crayfish Cherax quadricarinatus: Practical Diets with Soybean Oil as the Lipid Source.

As a new species in aquaculture, the lipid nutrition requirement for the juvenile redclaw crayfish Cherax quadricarinatus on a dietary basis on a practical formula needs to be evaluated accurately. In this study, the optimum dietary lipid level was explained by analyzing the growth performance, antioxidant state, lipid metabolism, and gut microbiota of C. quadricarinatus after an eight-week cultivation trial. Six diets with different soybean oil levels (named L0, L2, L4, L6, L8, and L10) were fed to C. quadricarinatus (11.39 ± 0.28 g). The results indicated that the specific growth rate and weight gain of crayfish fed the L4 and L6 diets were significantly higher than those of the other groups (P < 0.05). By the analysis of a second-order polynomial regression model according to growth performance (weight gain rate), the optimum lipid level in a practical diet for juvenile C. quadricarinatus was 9.67%. The survival, condition factor, and hepatosomatic index of crayfish were not significantly affected by dietary oil levels (P > 0.05). As the level of dietary lipids increased, the total antioxidant capacity and glutathione peroxidase activity in serum showed a tendency to rise and then fall and the enzyme activity was highest in crayfish fed the L6 diet. Gut lipase and pepsin activities showed the highest value in crayfish fed the L6 diet. There was no significant difference in acetyl-CoA carboxylase and carnitine palmitoyltransferase-1 contents in crayfish among all the groups (P > 0.05). The relative abundance of Proteobacteria in the phylum and Citrobacter in the genus showed a significant decrease in crayfish of the L10 diet, while the relative abundance of Firmicutes in the phylum markedly increased compared to that of the other groups (P < 0.05). In summary, the results indicated that the 10.39% (L6 diet) dietary lipid level could induce better growth performance, antioxidant ability, and digestive enzyme activity. Most of the fatty acid composition of muscle is not closely related to the fatty acid composition of the diet. Moreover, the composition and diversity of the gut microbiota of C. quadricarinatus were changed by high dietary lipid levels.

Influence of the source of spawners’ origin on oocyte maturity stages and suitability for artificial reproduction of wild pikeperch (Sander lucioperca) females during spawning season

Pikeperch is one of the major new fish species in freshwater aquaculture. Artificial reproduction is difficult in this species, and many aspects require further study. These include synchronization of female maturation, latency time, gamete quality and spawner survival rate. For these reasons, many fish farmers must constantly replenish their spawning pikeperch stock, often with wild fish. Data on the suitability for the reproduction of wild fish obtained in several lakes during the reproduction period were collected in this study. The findings indicated that larger fish (> 1.5 kg BW) and those obtained in larger and deeper lakes (> 12.0 m mean depth vs. < 5.0 m mean depth, respectively, for deep and shallow lakes) were more valuable to fish farmers during the spawning season when they were obtained because a higher percentage of suitability for artificial reproduction and a higher embryo survival rate was observed for them. The mean embryo survival rate was high and was 84.5 ± 3.9 % on the 3rd day after fertilization and 79.7 ± 3.4 % at hatching. Among the group of the smallest females (< 1.5 kg), the highest percentage of nonsynchronous oocyte maturation occurred. This result demonstrated the successful procedure of both artificial reproduction and a successful method for selecting females for spawning.

Technical-economic viability of white snook Centropomus viridis culture in floating cages in a coastal lagoon in northwestern Mexico

Snooks from the genus (Centropomus spp.) are an important fishery resource in the Americas and are a new species for marine aquaculture. Nevertheless, their production potential remains unknown. This study assessed the viability to grow-out Centropomus viridis juveniles raised in marine floating cages. At the nursery stage, 15,000 juveniles (0.8 ± 0.2 g) were stocked in one 235 m3 cage at a mean water temperature of 21 ± 3.4 °C. After 120 days, the juveniles reached an average weight of 43.6 ± 20.6 g. Subsequently, the juveniles were harvested and graded by weight to continue the grow-out process. Three groups were formed for the initial grow-out period: 30 g (G30); 40 g (G40); 60 g (G60). After a period of 270 days, the mean weights of G30, G40, and G60 were 522 ± 84, 565 ± 72, 600 ± 85 g, respectively. The average grow from the three groups showed 0.77 ± 0.18 g day−1 when they were cultured at temperatures < 24 °C, while at temperatures > 26 °C the mean growth rate was 3.07 ± 0.76 g day−1. Economic simulations, using sensitivity analyses showed that 10 USD/kg is the only final sale price that generates profitability with a production of 20 tons and survival of 60%. Our work suggests that the grow-out site should be located in an area with a tropical-subtropical latitude, in which water temperatures oscillate between 26 and 32 °C, and that 30 g juveniles should be used in order to improve survival during the rearing conditions in the initial grow-out stage. The results showed that C. viridis culture could be both technically and economically viable.

Final oocyte maturation (FOM) model and artificial reproduction of burbot spawners (Lota lota) originating from the F1 generation of a cultured stock in comparison to wild stock

The burbot (Lota L.) is one of the most promising freshwater new fish species for cold-water aquaculture. Due to the lack of availability of wild spawners, it is imperative to breed cultured spawners. In the present study, artificial reproduction of a cultured stock of burbot was carried out and then compared with wild fish reproduction results. Patterns of burbot final oocyte maturation were developed and they were compared during artificial reproduction of wild and cultured burbot. For the first time, a model of final oocyte maturation (FOM) was formulated in a hormonally stimulated female burbot. The relationship between the oocyte maturity stage is straightforward and, at a water temperature of 2 °C, progress by the next stage was observed in two-day intervals. This model was tested on a group of wild and cultured fish (generation F1) originating from the Vistula Lagoon (Northern Poland). In both cases, the very high utility of the proposed model in the artificial reproduction of burbot was confirmed. The fertilization was very high. In wild and cultured forms was similar and was over 95% (95.4 ± 0.3 and 95.3 ± 0.3 as mean ± SD for wild and cultured, respectively). The differences in the survival to eyed-egg-stage (92.2 ± 0.8 and 91.9 ± 0.7 for wild and cultured, respectively) and hatchability of eggs (91.1 ± 0.9 and 90.9 ± 0.8 for wild and cultured, respectively) were statistically insignificant. In summary, a cultured stock of burbot spawners can be successfully used for the stable production of the stocking material of this species.

Evaluating new species for aquaculture: A genomic dissection of growth in the New Zealand silver trevally (Pseudocaranx georgianus).

Aquaculture is the fastest‐growing food production sector worldwide, yet industry has been slow to implement genomic techniques as routine tools. Applying genomics to new breeding programmes can provide important information about pedigree structure and genetic diversity; key parameters for a successful long‐term breeding programme. It can also provide insights on potential gains for commercially important, yet complex, quantitative traits such as growth rate. Here we investigated a population of 1100 captive‐bred F1 silver trevally (Pseudocaranx georgianus), a promising new species for New Zealand aquaculture. We used whole‐genome information, coupled with image‐based phenotypic data collected over two years, to build the pedigree of the population, assess its genetic diversity, describe growth patterns of ten growth traits and estimate their genetic parameters. Successful parentage assignment of 664 F1 individuals showed that the pedigree consisted of a complex mixture of full‐ and half‐sib individuals, with skewed reproductive success among parents, especially in females. Growth patterns showed seasonal fluctuations (average increase across all traits of 27.3% in summer and only 7% in winter) and strong inter‐family differences. Heritability values for growth traits ranged from 0.27 to 0.76. Genetic and phenotypic correlations between traits were high and positive, ranging from 0.57 to 0.94 and 0.50 to 1.00 respectively. The implications of these findings are threefold: first, the best on‐growing conditions are in warmer months, where highest growth peaks can be achieved; second, size‐ and family‐based selection can be used as early selection criterion if pedigree structure and inbreeding risks are closely monitored; third, selection for body length results in concomitant increases in height and weight, traits of paramount importance for aquaculture. It is concluded that there is substantial potential for genetic improvement of economically important traits, suggesting that silver trevally is a promising species for selective breeding for enhanced growth.

FOOD AND FEEDING OF CHOCOLATE MAHSEER (NEOLISSOCHEILUS HEXAGONOLEPIS) FROM FRY TO JUVENILE STAGES IN CAPTIVITY

Chocolate mahseer, Neolissochilus hexagonolepis was reared from the juvenile stages in captivity to establish it as a new candidate species in hill aquaculture. Gut content analysis of fry showed that the food consisted of 50.48 % zooplankton, 29.72 % phytoplankton, unidentified matter 14.09 % and 5.71 % sand and mud. In fingerling stage, 56.33 % phytoplankton and 24.07 % zooplankton was recorded from the gut. Maximum phytoplankton percentage (60.65) was recorded during juvenile stage. The RLG (1.048 to 2.72) and GSI (3.92 to 9.65) accessed from fry till juvenile stage indicated the changing feeding habits from carni-omnivorous to herbi-omnivorous. Key words: Chocolate mahseer, food and feeding, captive rearing, Himalaya

Comparative Ecology of Feeding and Digestion of Two Notopterid Fishes Inhabiting River Punarbhaba in India

Resource partitioning among coexisting species leads to divergent changes in morphological, behavioural and physiological characteristics of animals providing insights in niche availability. Chitala chitala (Hamilton-Buchanan, 1822) and Notopterus notopterus (Pallas, 1769) are two Notopterid fishes belonging to order Osteoglossiformes found to coexist in Indian waters. Both the species command high market demand not only as food fish but also as aquaria fishes making them new candidate species for aquaculture. Feeding ecology of these species were studied through prey electivity analysis, calculation of Index of Relative Importance of food items, estimation of digestive enzymes accompanied by morphometric study. Toothed jaw and higher relative gape width makes C. chitala an efficient predator whereas N. notopterus with obliquely placed and slightly upturned mouth, prominent lower jaw, higher head and body depth, well-developed stomach establish N. notopterus as an omnivore. The results also highlight N. notopterus having larger niche breadth surviving on wide prey base in nature could justifiably be a more common species found in wider area of South East Asia whereas C. chitala being carnivorous, having smaller niche breadth enjoys relatively restricted geographical distribution.

Effect of Short-Term Rotifer Enrichment With Marine Phospholipids on Growth, Survival, and Composition of Meager (Argyrosomus regius) Larvae

Larval rearing and ongrowing of meager have experienced a great advance during the last years and nowadays this species is considered as one of the most important new species in Mediterranean aquaculture. However, larval nutrition in meager still needs some improvements especially regarding live prey enrichment and fatty acid composition. In this study, a trial for larval rearing of meager (Argyrosomus regius) using different commercial products for rotifer enrichment (Multigain, Red Pepper and concentrated microalgae) with and without phospholipids (PL), and with a different fatty acid composition, especially regarding DHA, have been used to assess the growth and survival of the larvae and check the effect of PLs in larval growth. Lipid class composition was the same among the larvae whereas % DHA was always higher in larvae fed Multigain and Red Pepper enriched rotifers. The dominant fatty acids in the PL of the larvae and PL of the diets were well-correlated and the results suggested a close relationship between the composition of dominant PL fatty acids in the rotifer and in the larvae, especially in the case of DHA and 16:0 that show a high correlation.

The microanatomy of the central nervous system and brain of the Indo-Pacific seahorse, Hippocampus barbouri, during development

The central nervous system (CNS) of Teleostei is a complex system of self-governance and its morphology is reflected in the physiological and reproductive behaviors. The Indo-Pacific seahorse, Hippocampus barbouri Jordan &amp;amp; Richardson, 1908, is a new candidate species for aquaculture in Thailand. In this study, we investigated the brain morphology of H. barbouri across various developmental windows. Light microscopic observations of adult brains revealed a large optic tectum in the mesencephalon, whereas the cerebral hemispheres and the cerebellum are of medium size. The detailed brain structures were generally similar to those of other teleosts; however, only five distinct layers were present in the optic tectum, including the stratum marginale, stratum opticum, stratum album central, stratum griseum central, and stratum periventriculae, versus six layers observed in other fish. One day after birth (1 DAB) the brain was a packed structure without any clear sub-structures. The number of capillaries in the optic tectum began to increase at 6 DAB, and at 14 DAB several features, including small blood vessels in the optic tectum and Purkinje cells, became noticeable. By 35 DAB, the optic tectum became highly vascularized and included five layers. Additionally, large Purkinje cells were developed in the cerebellum. Based on the brain development pattern, we speculate that the predatory ability of this fish starts to develop from 6 to 14 days after birth.

Squamous Cell Carcinoma (SCC) in Brown meagre (Sciaena umbra Linnaeus, 1758), a new candidate species for aquaculture in Mediterranean

A case of epithelial tissue tumors on the body of two adult Brown meagres (Sciaena umbra Linnaeus, 1758) is reported. Brown Meagre population of 20.000 was imported to sea cages on September of 2003 at 3g, to check the potential use of this species as a new candidate in Mediterranean aquaculture. The population had been kept for 8 years to serve as a genetic pool for further zootechnical investigation. The main pathology observed after 8 years in the sea cages were mainly ocular lesions (cataract) possibly due to natural aging and/or long culture period under high natural light intensity (UV radiation) and/or net injuries at a percentage of 1,32% of total cultured population. Apart from that, on two fish, reddish- white tumorous growths were evident on skin, macroscopically. Histologically, the timorous growths were diagnosed as Squamous cell carcinoma. Numerous rounded pearls and nests of epidermal proliferated cells were evident, some of which had a non-cellular center. There were also foci of necrosis and irregular deposits of keratin within the tumor tissue. Special stains (Ayoub-Shklar, Haematoxylin-Eosin &amp; Schiff’s Periodic Acid) were applied to the tissue for comparison. To our knowledge this is the first presented report of SCC in this species.

Isolation and experimental challenge of cultured burbot (Lota lota maculosa) with Flavobacterium columnare and Aeromonas sp. isolates.

Burbot (Lota lota maculosa) are a potential new species for commercial aquaculture. As burbot culture expands, there is a need to further define pathogen susceptibility and characterize aspects of the burbot immune response in an effort to assess fish health. A recent clinical diagnostic case from juvenile burbot reared at a commercial production facility resulted in the isolation and identification of Flavobacterium columnare along with several Aeromonas spp. The F. columnare isolate was assigned to genetic group 1 via multiplex PCR, a genetic group commonly associated with columnaris disease cases in rainbow trout (Oncorhynchus mykiss). Virulence of the F. columnare isolate was assessed in vivo in both juvenile burbot and rainbow trout. Additionally, several of the Aeromonas sp. case isolates were identified via sequencing (16S rRNA, gyrB and rpoD) and a putative A. sobria isolate (BI-3) was used to challenge burbot, along with a known virulent Aeromonas sp. (A141), but BI-3 was not found to be virulent. Burbot were refractory to F. columnare when challenged by immersion, and it is likely that this is a secondary pathogen for burbot. Although refractory in burbot, the identified F. columnare isolate (BI-1) was found to be virulent in rainbow trout.

Evaluation of commercial and experimental grower diets for use in intensive burbot (Lota lota maculosa) culture

Burbot (Lota lota maculosa) are the only true freshwater gadiforms (cod-like fish) and are a promising new species for cold water aquaculture. This “freshwater cod” produces a delicate white flesh fillet, the liver and roe are considered delicacies, and the skin can be manufactured into leather. Furthermore, burbot grow-out requires similar water quality parameters as trout production, and burbot have been found to be relatively refractory to most primary salmonid pathogens. Burbot could be reared at existing trout production facilities and represent a means of diversifying production in already established cold water aquaculture operations. For commercial burbot culture to succeed, optimal diet selection for grow-out must be determined. To address this, two feeding trials were conducted to evaluate the effect of different dietary formulations on the growth of juvenile and subadult burbot. Four dietary treatments at fixed rations were evaluated, Europa (commercial), Oncor (commercial), a formulated marine-like reference diet (Burbot 1; B1), and a formulated trout-like reference diet (Burbot 2; B2). Juvenile growth results indicated a difference in relative growth (RG; P < .001) and biomass gain (BG; P < .001) among the marine blend dietary treatments, with the fish fed B1 and Europa showing better growth than the Oncor and B2 diets in these cases. This is indicative of a preference for marine-type diets during the juvenile life stage of burbot. Growth results also indicate a difference in protein efficiency ratio (PER; P = .008) among the diets, with the fish fed Europa exhibiting the lowest protein utilization rate. Subadult growth results indicate no differences in RG (P = .771), SGR (P = .804), BG (P = .727) for fish fed any of the diets. Thus, it appears that the subadult burbot grow and perform equally well on trout-like formulations at this life stage. While additional studies are needed, results from this work are important and indicate general dietary preference of burbot at juvenile and grow-out stages. Such information can be used to guide feed related decisions for current or future producers interested in commercial burbot production.

Comparative evaluation of metabolic enzymes activities in different tissues of striped catfish, Pangasianodon hypophthalmus (Sauvage, 1878) fingerlings reared at ambient and higher temperature

A 60-days feeding trial was conducted to study the effect of higher temperature (32°C) in comparison to ambient temperature on different metabolic enzyme namely, Aspartate aminotransferase (AST), Alanine aminotransferase (ALT), Adenosine triphosphatase (ATPase), Acid Phosphatase (ACP) & Alkaline Phosphatase (ALP) activities in different tissues of Pangasianodon hypophthalmus. AST activity differs significantly (P 0.05). The ALT activity differs significantly (P 0.05) whereas ATPase activity in the liver at different temperature differ significantly (P<0.05). ACP activity does not vary significantly at different temperature whereas, ALP activity varies significantly at different temperature in liver and intestine tissues. The present study clearly shows that there is a temperature dependent change in the activity of the different metabolic enzyme in different tissue studied in comparison to the control at ambient temperature fed with different energy level diet. The finding of the present study suggests that the metabolic responses are variable at different temperature and different energy level which can affect the growth performances of this new candidate species for aquaculture.

First description of embryonic and larval development, juvenile growth of the black sea-cucumber Holothuria forskali (Echinodermata: Holothuroidea), a new species for aquaculture in the north-eastern Atlantic

Holothuria forskali (Delle Chiaje, 1823), also called the “black sea cucumber or cotton spinner”, is a native species from the North East Atlantic Area and the Mediterranean Sea. This holothurian is newly targeted to supply the Asian Market. In this context, developing aquaculture is important to prevent risks of over fishing. This paper describes the first successful reproduction, larval rearing, and juvenile growth of H. forskali performed in captivity. Reproduction of H. forskali was observed in April 2018. The reproductive behavior was similar to those observed in other species. The auricularia stage hatched after 4 days and lasted >30 days. Pentactula and metamorphosis to the benthic life was obtained after 40 days. Juveniles have been observed only after 90 days and measured 8 mm long. Juvenile growth was slow (0.1 mm/day) for this first breeding. This first description of H. forskali breeding and rearing in hatchery is encouraging for a new innovative and sustainable aquaculture.

Epidemiology of skin ulceration disease in wild sea cucumber Holothuria arguinensis, a new aquaculture target species.

Interest in wildlife epidemiology has increased in recent years. The control of diseases is critical for the survival of natural populations of economically valuable species. The present study is the first investigation of the etiology and epidemiology of skin ulceration disease in the sea cucumber Holothuria arguinensis, a new target species for fisheries and aquaculture in Europe. Bacterial cultures and molecular techniques were used to characterize this disease in animals collected during a survey across Ría Formosa Natural Park coastal lagoon in southern Portugal. Vibrio gigantis and V. crassostreae, which were both originally identified as disease agents in cultured oysters, were the most commonly isolated species of bacteria. Given that both sampling areas from which symptomatic H. arguinensis were collected were close to open oyster aquaculture facilities, this raises the possibility of an opportunistic infection, perhaps secondary to a decreased immune response caused by biotic or abiotic factors. An increase in prevalence of skin ulceration disease during the warmer season suggests that solar radiation and desiccation due to air exposure during low tide could be a cause of abiotic stress in the lagoon. Distributions of abundance and sizes of H. arguinensis in affected areas showed highest morbidity rates in adults. High fishery pressures throughout the study period could also cause elevations in prevalence and incidence rate of this disease. Skin ulcerative disease is endemic in this coastal lagoon. Disease monitoring is thus essential for the development of a conservation program to ensure the sustainability of fisheries and protection of natural resources.

Wreckfish (Polyprion americanus). New Knowledge About Reproduction, Larval Husbandry, and Nutrition. Promise as a New Species for Aquaculture

Four different wreckfish (Polyprion americanus) broodstock batches were maintained in research facilities under different photo and thermo-period conditions, one in Greece, the Helenic Center for Marine Research (HCMR, n = 3) and three in Spain: Instituto Español de Oceanografía (IEO, n = 13) in Vigo, Aquarium Finisterrae (MC2, n = 21) in A Coruña and Consellería do Mar (CMRM, n = 11). The CMRM includes two centers that work together: Instituto Galego de Formación en Acuicultura (IGAFA) and Centro de Investigacións Mariñas (CIMA), both in Pontevedra. During the five years of the project DIVERSIFY (Exploring the biological and socio-economic potential of new-emerging candidate fish species for the expansion of the European aquaculture industry, 2013–2018) works focused on the reproductive biology of the species, broodstock, and larvae nutrition and development of incubation and larval rearing protocols have been carried out. In terms of reproduction, catch methods of new wild animals, the reproductive cycle, sperm characteristics evaluation, and spontaneous and induced spawning methods have been described for wreckfish. Regarding nutrition, the positive effect of two types of enrichment on the fatty acid profiles of Artemia and rotifer has been verified. The relationship between the fatty acid profile of the diets supplied to the broodstock and the fatty acid profile obtained in the oocytes and eggs of the females fed with different diets, has also been demonstrated. Finally, early larval ontogeny has been described and incubation and larval rearing protocols have been proposed based on the results obtained in the different experiments of temperature, growth, survival, and larval feeding that were carried out.

Reproductive performance of asian catfish ( Hemibagrus wyckii Bleeker, 1858), a candidate species for aquaculture.

Background:Hemibagrus wyckii Bagridae is one of the important economic fish species that lives in the rivers and reservoir in Riau Province, Indonesia. The present study aimed to determine the reproductive performance of H.wyckii under culture conditions. Methods: A total of 10 female and 10 male fish were selected, and weight, length, characteristics of egg and sperm, and hatchery performance were measured. Eggs were fertilized using the dry method. Egg weight and egg diameters were measured for 50 eggs per female. Egg size (50 eggs for each fish) was measured using Labo microscope model L-711 using software camera 3. Then, saline solution was added over the eggs, followed by the addition of pooled sperm from 10 males. Results: Average relative fecundity, egg weight and egg diameter were 2060±512 eggs/kg fish, 29.86±1.21 mg and 2.67±0.26 mm, respectively. The fertilization rate and hatching rate were 60.91±4.68% and 42.91±2.92% respectively. Sperm characteristics such as volume per fish (mL), pH, concentration (per mL), motility (%) and duration of motility (second) were 0.82±0.20, 7.15±0.12, 3.68±0.15, 72.77±1.46 and 47.5±4.84, respectively. Conclusion: The study results and scientific observations regarding reproductive performance suggest that H. wyckii can be considered a new candidate species for aquaculture.