Sciaena Umbra Research Articles

Soundscape analysis can be an effective tool in assessing seagrass restoration early success

Restoration of vulnerable marine habitats is becoming increasingly popular to cope with widespread habitat loss and the resulting decline in biodiversity and ecosystem services. Lately, restoration strategies have been employed to enhance the recovery of degraded meadows of the Mediterranean endemic seagrass Posidonia oceanica. Typically, habitat restoration success is evaluated by the persistence of foundation species after transplantation (e.g., plant survival and growth) on the short and long-term, although successful plant responses do not necessarily reflect the recovery of ecosystem biodiversity and functions. Recently, soundscape (the spatial, temporal and frequency attribute of ambient sound and types of sound sources characterizing it) has been related to different habitat conditions and community structures. Thus, a successful restoration action should lead to acoustic restoration and soundscape ecology could represent an important component of restoration monitoring, leading to assess successful habitat and community restoration. Here, we evaluated acoustic community and metrics in a P. oceanica restored meadow and tested whether the plant transplant effectiveness after one year was accompanied by a restored soundscape. With this goal, acoustic recordings from degraded, transplanted and reference meadows were collected in Sardinia (Italy) using passive acoustic monitoring devices. Soundscape at each meadow type was examined using both spectral analysis and classification of fish calls based on a catalogue of fish sounds from the Mediterranean Sea. Seven different fish sounds were recorded: most of them were present in the reference and transplanted meadows and were associated to Sciaena umbra and Scorpaena spp. Sound Pressure Level (SPL, in dB re: 1 μPa-rms) and Acoustic Complexity Index (ACI) were influenced by the meadow type. Particularly higher values were associated to the transplanted meadow. SPL and ACI calculated in the 200–2000 Hz frequency band were also related to high abundance of fish sounds (chorus). These results showed that meadow restoration may lead to the recovery of soundscape and the associated community, suggesting that short term acoustic monitoring can provide complementary information to evaluate seagrass restoration success.

Chondroitin sulfate from heads of corb: Recovery, structural analysis and assessment of anticoagulant activity

In this study, glycosaminoglycans (GAGs) were extracted from corb (Sciaena umbra) heads and thoroughly examined for their structure. Through cellulose acetate electrophoresis, the GAGs were identified as chondroitin sulfate (CS), with a recovery yield of 10.35 %. The CS exhibited notable characteristics including a high sulfate content (12.4 %) and an average molecular weight of 38.32 kDa. Further analysis via 1H NMR spectroscopy and SAX-HPLC revealed that the CS primarily consisted of alternating units predominantly composed of monosulfated disaccharides at positions 6 and 4 of GalNAc (52.6 % and 38.8 %, respectively). The ratio of sulfate groups between positions 4 and 6 of GalNAc (4/6 ratio) was approximately 0.74, resulting in an overall charge density of 0.98. Thermal properties of the CS were assessed using techniques such as differential scanning calorimetry and thermogravimetric analysis. Notably, the CS demonstrated concentration-dependent prolongation of activated partial thromboplastin time (aPTT) and thrombin time (TT) while showing no effect on platelet function. At 200 μg/mL, aPTT and TT coagulation times were 1.4 and 3.7 times faster than the control, respectively. These findings suggest that CS derived from corb heads holds promise as an anticoagulant agent for therapy, although further clinical investigations are necessary to validate its efficacy.

Effect of Stocking Density on Survival and Growth of Brown Meagre Sciaena umbra (L.) Larvae

Effect of Stocking Density on Survival and Growth of Brown Meagre Sciaena umbra (L.) Larvae

Rhythmic properties of Sciaena umbra calls across space and time in the Mediterranean Sea.

In animals, the rhythmical properties of calls are known to be shaped by physical constraints and the necessity of conveying information. As a consequence, investigating rhythmical properties in relation to different environmental conditions can help to shed light on the relationship between environment and species behavior from an evolutionary perspective. Sciaena umbra (fam. Sciaenidae) male fish emit reproductive calls characterized by a simple isochronous, i.e., metronome-like rhythm (the so-called R-pattern). Here, S. umbra R-pattern rhythm properties were assessed and compared between four different sites located along the Mediterranean basin (Mallorca, Venice, Trieste, Crete); furthermore, for one location, two datasets collected 10 years apart were available. Recording sites differed in habitat types, vessel density and acoustic richness; despite this, S. umbra R-calls were isochronous across all locations. A degree of variability was found only when considering the beat frequency, which was temporally stable, but spatially variable, with the beat frequency being faster in one of the sites (Venice). Statistically, the beat frequency was found to be dependent on the season (i.e. month of recording) and potentially influenced by the presence of soniferous competitors and human-generated underwater noise. Overall, the general consistency in the measured rhythmical properties (isochrony and beat frequency) suggests their nature as a fitness-related trait in the context of the S. umbra reproductive behavior and calls for further evaluation as a communicative cue.

Movements and spatial distribution of an endangered fish (Sciaena umbra) within a marine protected area

The brown meagre (Sciaena umbra) is an endangered species, which requires specific protection measures to ensure its conservation. These measures need to be informed by high-quality scientific knowledge on their space use patterns. Here, we used acoustic telemetry to assess its seasonal movement patterns and habitat use within a marine protected area (MPA). Our results suggested that S. umbra is a highly sedentary species (home range < 1.0 km2) and, therefore, the MPA is extensive enough to protect the local population. Their population was discretely distributed in two main areas within the MPA, which was likely a result of habitat segregation and density-dependent movements. The temporal variability of their movements further uncovered when and where spawning occurs (mainly, but probably not only, in the fully protected area in June) and indicated that spillover of this species is limited but still possible. Overall, we highlight the importance of MPAs in the recovery of S. umbra, we advocate the need to perpetuate the current national fishing bans and extend it to other countries in the Mediterranean region, and we emphasize that considering the fine-scale movements of S. umbra in future management actions is key to achieving a successful recovery of their populations.

Electric boat underwater radiated noise and its potential impact on species of conservation interest

Electric boats are thought to be noiseless, but in-situ measurements are generally rare. The Underwater Radiated Noise (URN) of 8-m Trimaran Pontoon Boat with two outboard electric engines was measured in the Miramare Marine Protected Area (Trieste, Italy), together with the URN of a fibreglass 5-m boat, with a outboard gasoline engine, for comparisons. International standards and guidelines for shallow waters were considered. URN were provided in one-third octave band and in narrow band spectra. The electric boat produced a low input of underwater noise at low frequencies. Given a low-frequency hearing sensitivity, the listening space reduction (LSR) was lower when generated by the electric than by combustion engine boat for the brown meagre, a local Teleost fish. No difference was found for the bottlenose dolphin LSR although continuous, tonal, high frequency components generated by the electric boat are expected to be highly detrimental for the bottlenose dolphin.

Population Structure, Exploitation Status, and Prospects of Brown Meagre Sciaena umbra Linnaeus, 1758 From the Turkish Coast of the Black Sea

The brown meagre (Sciaena umbra Linnaeus, 1758) population has experienced dramatic population declines, and it was regionally assessed as “Near Threatened” in the Mediterranean. In this study, the current status of brown meagre populations in the Black Sea was evaluated by estimating growth and mortality rates based on age readings from the otolith. All specimens were collected by commercial trammel nets between March 2019 and February 2020 in the Turkish coast of the Black Sea. A total of 324 brown meagre were sampled during the study period, ranging in age from 0 to 26. The peak spawning season of the species was from June to July. The Von Bertalanffy growth parameters of (L∞ = 54.15, k = 0.14 yr-1, t0 = -3.11) supports previous studies and suggests that brown meagre is a long-lived and slow-growing species. The exploitation ratio of 0.53 for females and 0.47 for males. Life-history features and mortalities indicate that the brown meagre has relatively high fertility but may be undefended to intense fishing pressure. However, the impact of overfishing, pollution and climate change can have increasingly detrimental effects on the overall population size of this population.

Global patterns and environmental drivers of suitable habitat for Dentex dentex and Sciaena umbra along the Corsican coast

Abstract Improving the effectiveness of marine spatial management is crucial to preserve marine ecosystems and also to support the fisheries economy. In this study, we aimed to determine the spatial distribution and suitable habitats (spawning and nursery sites) of Sciaena umbra and Dentex dentex using catches data in Corsica Island. Random forest models have been used as they are highly accurate and are suited to predict rare species distribution. Predictive maps of spatial distribution based on presence/absence data showed a high degree of spatial variability between species. Suitable habitats were close to shore in shallow waters for S. umbra and deeper and further offshore for D. dentex. We also observed that spawning sites were mainly located on the west coast, while nursery areas were distributed all around the island for D. dentex. In addition, we demonstrated the important contribution of environmental factors and local habitats (depth and Posidonia oceanica meadows) in the selection of their suitable habitats. Our results provide new knowledge for understanding ecological processes such as the selection of suitable habitats by fish species. Based on this information, spatial mapping can be implemented to improve the effectiveness of resource management over the long term.

Wild fish and seafood species in the western Mediterranean Sea with low safe mercury concentrations

A total of 1345 specimens belonging to 58 different species of wild fish and seafood from the western Mediterranean Sea were analyzed to assess total mercury levels and to estimate which species meet the EU recommendations for human consumption (0.5 μg g−1 ww) in all cases. All fish species were caught off the Mediterranean coasts and intended for human consumption. All specimens were collected from local markets located in Spain, Italy and France that sell fish caught by local fishermen (Eivissa, Menorca, Mallorca, Alacant, L'Ampolla, Ametlla de Mar, Marseille, Genoa, Civitavecchia, Alghero) at different time periods. Mercury concentrations were measured by thermal decomposition-gold amalgamator-atomic absorption spectrometry.Only thirteen species were found that did not exceed 0.5 μg g−1 ww in any specimen analyzed. These safe species were sardines (Sardina pilchardus), anchovies (Engraulis encrasicolus), blue whiting (Micromesistius poutassou), picarel (Spicara smaris), blackspot seabream (Pagellus bogaraveo), gilthead seabream (Sparus aurata), pearly razorfish (Xyrichtys novacula), surmullet (Mullus surmuletus), painted comber (Serranus scriba), brown meagre (Sciaena umbra), salema (Sarpa salpa), common dolphinfish (Coryphaena hippurus) and squid (Loligo vulgaris). These species occupy different trophic levels, have different lengths and average weights, but show a low mercury concentration than others living in the same environments.Potential human consumption of these species as sole source of fish would imply estimated weekly intakes representing between 49% and 70% of the recommended provisional tolerable weekly intake of methylmercury in the worst case.Health authorities should pay specific attention to species that do not meet EU thresholds and make appropriate precautionary health recommendations, especially for pregnant women and children.

Embryonic and larval development of Corsican brown meagre, Sciaena umbra (Linnaeus 1758), rearing in captivity from the Mediterranean Sea

Embryonic and larval development of Corsican brown meagre, Sciaena umbra (Linnaeus 1758), rearing in captivity from the Mediterranean Sea

Ontogeny of swimming performance of hatchery-reared post-larvae and juvenile fish: a case of two threatened Mediterranean species.

Swimming performance is a well-established key physiological parameter of fish that is highly linked to their fitness in the wild. In the context of fish restocking purposes, it therefore appears crucial to study this specific behaviour. Here, the authors investigated intra and interspecies differences in the swimming performance of hatchery-reared post-larvae and juveniles belonging to two Mediterranean candidate threatened species, the common dentex, Dentex dentex (Sparidae), and the brown meagre, Sciaena umbra (Sciaenidae), with body sizes ranging from 8 to 37 mm total length (TL, from 24 to 58 days post-hatch). The swimming abilities were estimated through the calculation of their critical swimming speed (Ucrit ), their relative Ucrit and their Reynolds number (Re ). Two different patterns were observed between D. dentex and S. umbra, showing a different effect of ontogeny on the performance of both species. The relative Ucrit of S. umbra decreased linearly through ontogeny, whereas the relative Ucrit and Ucrit of D. dentex increased linearly through the range of sizes tested. The ontogenetic change in Ucrit of S. umbra occurred in two stages: a first stage of sharp improvement and a second stage of a slow decrease in performance. Both stages were separated by a breakpoint that coincided with the appearance of a refusal to swim behaviour that occurred shortly after the end of metamorphosis and can potentially be associated with the establishment of this species sedentary behaviour. The swimming performance of both species showed ontogenetic differences. Sciaena umbra had the highest relative performance when its body sizes were the smallest, whereas D. dentex showed the highest relative performance when its body sizes were the largest. These results will be linked to future research on both of these species concerning their escape, exploratory and predatory behaviours, and for restocking purposes to draw a more realistic overview of hatchery-reared juvenile performance. Knowledge of both species' behavioural and swimming performance through ontogeny is important to consider when using hatchery-reared fish juveniles for restocking, as size-at-release can have a large impact on fish survival and thus on restocking success.

Ecological, Social and Economic Aspects of Italian Marine Spearfishing Tournaments (2009-2020)

Marine recreational spearfishing is practiced by a small proportion of recreational fishers and ecological, social and economic aspects of such activities are poorly understood with respect to recreational angling. The Italian Federation of Sport Fishing and Underwater Activities (FIPSAS) started in 2009 the collection of catch data related to Italian spearfishing tournaments. Here, we provide the first snapshot of this catch data regarding 48 tournaments organized in 29 different Italian localities from 2009 to 2020. We also developed a survey to collect social and economic information that has been administrated to participants to the tournaments. We retrieved 8843 specimens caught by spearfishers, which accounted for 33 species and a total biomass of 5665 kg (mean individual mass ± standard error; 0.64 ± 0.01 kg). The five most frequently species represented 78% of the specimens caught (white seabream, Diplodus sargus 48%; brown wrasse, Labrus merula 12%; brown meagre, Sciaena umbra 9%, green wrasse, Labrus viridis 5%; salema, Sarpa salpa 4%). The overall catch per unit effort for all the tournaments was 0.47 ± 0.01 kg/spearfisher/h, and we showed interesting effects of type of tournaments and type of displacement on it. We also assessed the accuracy of participants to catch fish in accordance to tournaments-specific minimum weight limits. The five most caught species showed that spearfishers committed errors around 50 g below the weight limit. The survey showed that spearfishers participating to tournaments are trophy-fish oriented (i.e., they would rather catch one or two big fish than ten smaller fish), but not particularly catch oriented (i.e., they are just as happy if they do not shoot the fish they see and a fishing trip can be successful even if no fish are caught). Regarding the motives for fishing, they fish for experiencing adventure, excitement and new and different things as well as to be underwater. Participants spent from 2 to 26 days in the tournament locations (median equal to 7 days), which implies a total expenditure to solely participate to the tournaments ranging from 800 to 3500 Euros (mean ± standard deviation; 1800 ± 591 euros). This study represents the first ecological, social and economic baseline knowledge for an integrative management of contemporary spearfishing tournaments.

Habitat selection of high trophic-level predatory fishes in protected and unprotected areas: The effects of density and maturity stage

Marine Protected Areas (MPAs) are useful tools for the conservation of fishes, providing that they include the essential habitats for the focal species. Habitat selection may depend on external (i.e., environmental conditions, food availability, and shelter) and internal (i.e., density-dependent processes) factors. Additionally, most fishes undergo ontogenetic shifts along their life cycles, thus, understanding the habitat requirements at each stage is of great interest for the correct design and functioning of MPAs. Here, we evaluated habitat preferences of high-level predatory fishes, namely Epinephelus marginatus, Epinephelus costae, Mycteroperca rubra, Dentex dentex, Sciaena umbra and Sphyraena viridensis to assess differences between species, maturity stages and density of fish. To do so, we applied Species Distribution Models (SDMs) in protected and unprotected areas along the coast of Murcia (SE Spain) to determine if those areas are properly located for the conservation of the focal species. We included three areas with different density of fishes. One area with high density in the long-term protected Cabo de Palos-Islas Hormigas MPA, and two with low density in the newly established Cabo Tiñoso MPA and the unprotected area of Cabo Cope. We evaluated the environmental variables that affect the occurrence of the species at two life stages, before and after achieving size at maturity. SDMs showed that bathymetry, habitat complexity and rocky bottoms were the most important drivers determining species distribution in both areas with high and low density of fish, although there were differences in the contribution of the variables at each location. Additionally, we found that habitat requirements were different for the immature and mature individuals, generally being the immatures the most sensitive to changes in habitats. Both MPAs and the unprotected area largely included areas of high suitability for the studied species, indicating that the MPAs are established in proper areas, and suggesting another area for the establishment of a new MPA to enhance a MPA network in the region.

Boat-induced pressure does not influence breeding site selection of a vulnerable fish species in a highly anthropized coastal area

The brown meagre (Sciaena umbra) is a vulnerable vocal fish species that may be affected by boat noise. The breeding site distribution along the anthropized Venice sea inlets was investigated, by using the species' chorusing activity as a proxy of spawning. Passive acoustic campaigns were repeated at 40 listening points distributed within the three inlets during three-time windows in both summer 2019 and 2020. The role of temporal, morphological, and hydrodynamic variables explaining the observed distribution patterns was evaluated using a GLM approach, considering also human-induced pressures among the candidate predictors. The GLM analysis indicates a higher probability of recording S. umbra chorus after sunset in deeper areas of the inlets, characterized by low water current, while the underwater noise overlapping the species' hearing range and boat abundance did not play any role. This suggests that the species' breeding site choice in the inlets was not influences by boat-induced pressure.

Residual Levels of Mercury, Cadmium, Lead and Arsenic in Some Commercially Key Species from Italian Coasts (Adriatic Sea): Focus on Human Health.

This study provides information on the potential human health risk of Hg, Cd, Pb and As exposure from consumption of two fish species (Umbrina cirrosa and Sciaena umbra) in the general population and in high-level fish consumers. The concentrations did not show significant differences between the two species, and no fish length element level–body-length relationship was observed, except for Hg. The average metal(loid) levels, irrespective of species, varied in the following ranges: Hg = 0.18–0.19, Cd = 0.07–0.10, Pb = 0.10–0.12, As = 0.59–0.69 μg g−1 w.w. The concentrations remained below the maximum permissible limits (MPLs) for human consumption, except for Cd. The estimated intakes of Hg, Cd and Pb in both consumption scenarios were lower than the respective PTWI/PTMIs, as well as those of inorganic As, which were even lower than the BMDL01. The non-carcinogenic risk (THQ) did not reveal any concerns, except for Hg. The lifetime health cancer risk (ILCR) suggested hazard exclusively from Cd, although for high-level fish consumers, even the ILCR of inorganic As was, in some cases, above the acceptable range. Continuous monitoring of metal(loid) levels in these fish is strongly recommended because the results demonstrate the occurrence of potential health risks, especially in high-level fish consumers, due to the presence of Hg and Cd.

Fish acoustic community structure in Neptune seagrass meadows across the Mediterranean basin

Abstract Sound production represents an integral part of social communication in many teleost fish; however, few studies have investigated the structure, organization and variability of fish sounds at the community level. Fish acoustic community structure was recorded simultaneously in three sites located along the Mediterranean basin within the endemic habitat of Posidonia oceanica seagrass beds. Acoustic diversity and species‐specific sound features were expected to differ between locations. We predicted that, in communities characterized by higher acoustic richness, fish species would specialize in their use of acoustic resources (i.e. realized acoustic niche compression), while the overall allocation of resources within the community signal space would expand. The fish acoustic communities inhabiting Posidonia beds were characterized by the same main contributors (the /Kwa/, Ophidion rochei and Sciaena umbra sound types). However, their relative occurrence, abundances and use of acoustic resources were site‐specific. Acoustic diversity differed between geographic locations. The range of spectral and temporal resources exploited by the fish acoustic community was wider in sites where acoustic richness was at its highest score. Ophidion rochei was highly specialized in its use of temporal resources where acoustic richness was higher, whilst S. umbra appeared less efficient in specializing the use of spectral and temporal resources. By showing that the same species can exploit different acoustic resources between locations, this study supports the concept of Acoustic Niche plasticity (i.e. plasticity of acoustic resources allocation within a species). The results suggest that the degree of acoustic niche plasticity might be determined by the species‐specific degree of sound‐producing system plasticity. In turn, different degrees of acoustic niche plasticity might determine different species‐specific levels of acoustic adaptability to changing biotic or environmental conditions.

New host findings of two parasitic isopods (Flabellifera: Cymothoidae) found on some fish caught in the Dardanelles Strait (Çanakkale, Turkey)

Seven cymothoid species are identified in parasitological studies conducted in the Dardanelles Strait between May 2018- May 2020. The Cymothoids identified are as follows: Mothocya epimerica Costa, 1851, Nerocila bivittata (Risso, 1816), Anilocra frontalis H. Milne Edwards, 1840, Ceratothoa oestroides (Risso, 1826), Ceratothoa parallela (Otto, 1828), Ceratothoa italica Schiödte &amp;amp; Meinert, 1883, Emetha audouini (H. Milne Edwards, 1840). A. frontalis and C. italica are found for the first time from Sciaena umbra Linnaeus, 1758 and Boops boops (Linnaeus, 1758) respectively. Although several reports of these parasites have been given from Turkey, the morphological characters of three species have not been given. The drawings, descriptions of the mouthparts, pereopods, and pleopods of N. bivittata, A. frontalis, C. italica are given in this study.

Seasonal influence on the bathymetric distribution of an endangered fish within a marine protected area

The spatio-temporal variability of fish distribution is important to better manage and protect the populations of endangered species. In this sense, the vertical movements of a vulnerable and protected species, Sciaena umbra, were assessed in a marine protected area (the Réserve Naturelle Marine de Cerbère-Banyuls, south of France) to study the variability of their bathymetric distribution at different time scales. Twenty adults were marked with acoustic transmitters and acoustically monitored over 2.5 years. This revealed that some individuals remained at shallow waters (< 8 m) all year round, while others presented vertical segregation at deeper waters during the cold months (mean depth of 22.5 ± 0.04 m) and all aggregated in shallow waters during the warm months. The brown meagre was more active during the night, except in June and July when peaks of activity were observed at dusk. These patterns are likely associated with foraging and reproductive behavior during the cold and warm periods, respectively, and likely regulated by water temperature and the depth of the thermocline. Here, we provide valuable information on when and where in the water column critical periods of S. umbra life cycle are expected to occur, which should be considered in management and protection plans.

Sound discrimination of two sympatric, threatened fish species allows for their in situ mapping

Abstract Human impacts on marine ecosystems are increasing and the number of fish species listed in the Red List is constantly growing. In the Mediterranean Sea, seven of the 10 bony fishes defined as Threatened by the IUCN are known to be vocal, including the target species of this study: the shi drum (Umbrina cirrosa Linnaeus, 1758) and the brown meagre (Sciaena umbra Linnaeus, 1758). As a result, non‐invasive passive acoustic monitoring (PAM) can be used to pinpoint their distribution at sea. However, for PAM to be effective, reliable acoustic discrimination is required because the sounds they emit during reproduction are remarkably similar (i.e. short broadband pulsed sounds). The shi drum and the brown meagre are closely related, elusive, vocal sciaenids, partially overlapping in their ecological niche. During summer 2019, three PAM surveys were conducted along the tidal inlets of the Venice lagoon (Italy). Here, the calls of both species have been recognized according to their temporal features: shi drum sounds were made up of a lower number of longer pulses with a different envelope, repeated at a lower rate than those of the brown meagre. Further, shi drum and brown meagre sounds of different origins (aquaculture and semi‐natural conditions) were analysed and compared with those collected during the survey of the study area in order to validate the field collected data. Call discrimination allowed for a fine‐scale species mapping, showing a partially overlapping distribution of the two species along the inlets. This is the first case in which two sciaenids have been documented to share their reproductive habitat in the Mediterranean Sea. This study demonstrates that it is feasible to acoustically monitor the target species even in those parts of the Mediterranean Sea where they co‐exist. This, in its turn, could provide managers with the required data for effective conservation measures to be implemented.

First Results on Spawning and Larval Rearing of the Brown Meagre (Sciaena umbra)

The aim of the present study is to investigate spawning and larval rearing of brown meagre (Sciaena umbra). This is an important species in the Mediterranean Sea because of its beauty, calm swimming, large otoliths, souvenir potential, aggregative behaviour, excellent flesh and accessibility. Although this species is regarded as Near Threatened (in IUCN Red List Status), the demand increases the fishing. Green water technique was used for rearing the brown meagre larvae. Diameter of eggs was recorded as 1457.31±47.29 µm. Yolk was homogenous with oil globules of 371.59±18.15 µm at the centre. Hatching process began after 39 hours. Hatching rate (HR) was observed as 92.17±0.24%, and larvae inflated swim bladder around 97.33±0.94%. The brown meagre juveniles reached to 40.08±1.98 mm of total length (TL) with 10.96±0.08 mm body height (BH) and 662.27±21.23 mg body weight (BW) after 55 days of post-hatching. Survival (SR) was recorded as 72.5±0.70% at the end of study. Since the brown meagre is a threatened species, with high economic interest, is a possible candidate for commercial aquaculture both food and restocking the depleted natural fisheries.