Johnius Belangerii Research Articles

Does shrimp trawling contribute to the decline in sciaenid stocks?

Trawling is widely used to exploit shrimp resources worldwide and is considered a highly destructive fishing method due to the high by-catch and discard rates. By-catch levels in shrimp trawling are reported to be 5–10 times the target catch, especially in the subtropics and tropics. This study assesses the status of sciaenids landed by mechanized shrimp trawls (single day operated), off Hendala, Sri Lanka. Catch data and samples were collected at the Hendala fish landing site (6°59'25.5"N 79°52'27.9"E) by making biweekly field visits from January to December 2021. On each sampling day, 50–60 % of operating shrimp trawlers were randomly sampled, and by-catch samples (n = 3) of ∼2 kg each were collected to identify the taxonomic status of sciaenids and their composition. The size at first sexual maturity (Lm) and population parameters of dominant species in the catches were also assessed. Of the estimated total annual by-catch of 19.67 tons, the Sciaenidae family accounted for 31 %. Fourteen sciaenid species belonging to 7 genera including Johnius (Johnieops) dussumieri, a new record for Sri Lanka, were reported in this study. Otolithes ruber (27 %) made the highest contribution followed by Kathala axillaris (21 %), Johnius belangerii (15 %), Johnius macropterus (15 %), and Johnius borneensis (10 %). The Lm (cm) of 3 dominant species, O. ruber, J. belangerii and K. axillaris was estimated as 20.6, 13.8 and 11.0, respectively. Immature individuals of 85.5 %, 73.4 %, and 39.1 % respectively, were caught before reaching their first maturity. Estimates of population parameters suggested that non-target species like O. ruber, J. belangerii and K. axillaris are showing signs of over-exploitation. Management measures such as gear modification and introduction of by-catch-reducing devices as well as awareness programmes will be helpful to sustain the livelihood of fishers while protecting aquatic biodiversity and ecological sustainability.

Morphometrics and Truss-networking distances among three species of croaker (Johnius borneensis, Johnius argentatus and Johnius belangerii) from Bangladesh coast of the Bay of Bengal

Morphometric features are efficiently used for the differentiation of species and long-term management of fish populations. Truss analysis is a frequently used taxonomic method as well as a stock identification tool to dissimilitude the morphologically similar species. Using landmark-based truss networking techniques following 18 morphometric lengths, 10 meristic counts, and 23 truss-network distance, the morphological variation of three croaker species viz. Johnius borneensis, Johnius argentatus, and Johnius belangerii were examined from Bangladesh coast. Data were analyzed and visualized through univariate ANOVA, canonical discriminate function analysis (DFA), and principal component analysis (PCA). Results found that the first DFA was responsible for 80.6% & 81.1%, whereas the second DFA was responsible for 19.4% & 18.9% variations among three species for the morphometric and truss-distances, respectively. In addition, 14 out of 18 morphometric and 12 out of 23 truss-network measurements were significantly different (p < 0.05) among means of three species. 1st PCA found 70.76% & 64.49% explained variations and 2nd PCA displayed 12.8% & 11.5% explained variations respectively for morphometric and truss distances. The findings of the study demonstrates that J. borneensis and J. belangerii are highly morphologically similar and J. argentatus is completely distinct which might be due to their physiological and genetic variations. The present study might be helpful in differentiating species and managing existing stocks of marine fish. Further studies regarding the molecular characterization of the Cytochrome c oxidase subunit I (COI) gene could confirm the genetic variations among these species. Bangladesh J. Zool. 51(3): 233-251, 2023

Occurrence of microplastics in fish gastrointestinal tracts belongs to different feeding habits from the Bangladesh coast of the Bay of Bengal.

The Bay of Bengal (BoB) is home to a range of commercially important species with different food habits and feeding features. Microplastic (MP) contamination in the fish of BoB, like in many other marine environments, is a significant environmental concern. The study aimed to investigate the presence of microplastics (MPs) in the gastrointestinal tracts (GITs) of selected commercial marine fishes from the Bangladesh coast of the BoB. Six fish species (Escualosa thoracata, Tenualosa ilisha, Johnius belangerii, Trichiurus lepturus, Planiliza parsia, and Mystus gulio) were investigated (n = 120) following hydrogen peroxide digestion, and floatation (saline solution) protocols. After analyses, a total number of 696 MPs (dimension 0.3 to 5 mm) were identified. Moreover, the highest occurrence of MPs in fish GITs was found in planktivorous fish (average of 7.7 items/individual), followed by omnivorous (average of 5.2 items/individual), and carnivorous fish (average of 4.6 items/individual) (p < 0.001). However, planktivorous E. thoracata showed the highest number of MPs per g of GIT (average of 30.99 items/g GIT), whereas T. ilisha showed the lowest count (average of 0.77 items/g GIT). Different types of MPs (fibers (19 to 76%), fragments (6 to 61%), films (8 to 35%), microbeads (0 to 5%), and foams (0 to 2%)) were also observed. In terms of the color of MPs, the transparent, black, green, and blue types were the most common. Polymers were found as polyethylene (35 to 43%), polyethylene terephthalate (28 to 35%), polyamide (20 to 31%), and polystyrene (0 to 7%). The study provides a significant incidence of MPs in fish from the Bangladesh part of the BoB, which is very concerning. Therefore, long-term research is indispensable to ascertain the variables affecting the presence of MPs in fish, their origins, and their potential effects on the BoB fisheries. Stringent policies on plastic use and disposal should be strongly urged in this coastal region.

Potential of Johnius belangerii and Thryssa hamiltonii as fishmeal in Deli Serdang, North Sumatera, Indonesia

An increasing problem in the Indonesian fishing industry is the scarcity of fish feedstuffs due to limited availability of raw materials, rising production costs, and climate change. Fishmeal are crucial in farms as they contain high-quality nutrients that are easily digestible by livestock. This study aims to observe the potential of the region as a producer for layer feedstuffs from fishmeal. This research used 10 kg of fresh Johnius belangerii’s fish and Thryssa hamiltonii’s fish with 5 kg each. The heads of both types of fish were collected to calculate their rendement. The results showed that the rendement percentage of Thryssa hamiltonii’s fish heads was 38.64%, while the yield percentage of Johnius belangerii fish heads was 36.83%. Based on the results it can be concluded that this region has significant potential in fishmeal from fisheries waste. 3 warehouses, Deli Serdang Regency, particularly Pantai Labu, can produce 19,108 kg of Thryssa hamiltonii fish in a year, utilizing 615.1 kg of head waste, 299 kg of offal waste, and 30.14 tons of protein. Johnius belangerii fish, weighing 20,299 kg with 623 kg of waste and 20.8 tons of protein content, are also produced in Deli Serdang Regency.

Assessing the exploitation status of Johnius belangerii in Zhanjiang Bay.

Fishery stock assessment is the basis of fishery management. This study explored the applicability of the Length-Based Spawning Potential Ratio method (LBSPR) to assess the exploitation status of data-limited fisheries. Using data from bottom trawl surveys in Zhanjiang Bay, the study estimated the relative fishing mortality (F/M) of Johnius belangerii stock. The results showed that the average lengths at 50% and 95% selectivity (LS50 and LS95) were 105 mm and 145 mm, respectively, both of which are smaller than the lengths at 50% and 95% sexual maturity length (L50 = 125 mm and L95 = 167 mm) determined via the logistic curve. The estimated spawning potential ratio (SPR) was 0.15 significantly below the reference threshold of 0.2. The study recommended the establishment of a minimum size range (137 to 150 mm) length for harvesting Johnius belangerii to enhance their reproductive potential. It also emphasized the importance of scientific monitoring of fishery resources and the ecological environment in Zhanjiang Bay to ensure sustainable management.

Feeding habits of four-finger threadfin fish, Eleutheronema tetradactylum, and its diet interaction with co-existing fish species in the coastal waters of Thailand.

This study assessed the feeding habits of four-finger threadfin fish, Eleutheronema tetradactylum, and its diet relationship with other fish species in the tropics. Fish samples were collected from four locations along the coastal regions of Thailand. A whole year field sampling event was conducted to investigate the diet relationship of threadfin fish with other ten co-existing fish species in Pattani Bay during January 2021 and January 2022. E. tetradactylum was an active and specific predator with significant diet shift during ontogeny. Specifically, the juvenile fish fed largely on zooplankton especially Acetes/shrimp postlarvae, and small sized-fish fed on penaeid shrimps, while medium and large-sized fish shifted their diets to a combination of penaeid shrimp, fish and squid. Size and sex of fish as well as site of collection significantly affected gut fullness index and average number of food type (p<0.05). Transitional sex fish predated almost entirely on other fishes (87.2%), whereas male and female fish fed mainly on penaeid shrimp (66.5%) and other fish (51.3%), respectively. Fish size and mouth opening controlled the size of prey, with the larger fish with larger mouth-opening fed primarily on the larger size of prey. Moreover, E. tetradactylum shared its diets inclusively with Epinephelus coioides, Johnius belangerii, Scomberomorus commerson, Scomberoides lysan, Otolithes ruber and Lutjanus russelli. Penaeid shrimp and teleost fish were the main food types shared by these fishes. This study provided important information on the feeding habits of E. tetradactylum and its diet relationship with other co-existing fish species living in the same habitat of a tropical coastal region.

Gastric Contents Analysis of Gulamah Fish (Johnius belangerii) Obtained In West Dumai Subdistrict and East Dumai Subdistrict

Gulamah fish (Johnius belangerii) is one type of marine fish found in Dumai waters. The study aimed to analyze the composition of natural feed on the stomach contents of gulamah fish obtained in Dumai. Research methods are survey methods, sampling is done by purposive sampling. The study was conducted in April-June 2022. Gulamah fish samples collected were 60 fish (in West Dumai Subdistrict 30 fish and East Dumai Subdistrict 30 fish). Fish samples were divided into 3 size classes, namely 3.1-8.3 cm; 8.4-13.5 cm and 13.6-18.7 cm. The results showed that the composition of food in the stomach contents of gulamah fish obtained in West Dumai Subdistrict is the size of class I (detritus IP 50%; and fish IP 50%), Class II (detritus IP 64%; fish IP 17.8%; shrimp IP 13.4%; and shellfish IP 4.8%) and Class III (detritus IP 5.6%; fish IP 83%; shrimp IP 5.6%; and shellfish IP 5.9%). The composition of food on the stomach contents of fish obtained in East Dumai Subdistrict consists of class I Size (detritus IP 57%; fish IP 10%; and shrimp IP 33%); Class II (empty stomach contents); and Class III (shrimp IP 100%). This indicates that gulamah fish (J. belangerii) is classified as a carnivorous fish.

Evaluating the stock status of 10 croaker species landed along the north-eastern Arabian Sea using the length-based Bayesian biomass approach

India accounts for nearly 60% of the croakers caught in the Indian Ocean. The north-west (NW) coast of India is the most productive fishing ground for croakers and contributes almost half of the nation’s croaker catch. Lesser sciaenids (small- and medium-sized croakers) are the multi-species complex landed by commercial trawlers along the NW coast of India. Despite several notable changes in the fishing pattern in the region, such as the emergence of multi-day fishing and increasing dominance of pelagic trawling, there is no recent assessment of this major demersal fishery group. The present study evaluates the stock status of 10 species of lesser sciaenids forming the commercial fishery in the region using length frequency data collected during 2020–2021. The assessment was made using the length-based Bayesian biomass (LBB) estimation method. The indicators of relative biomass (B/B0 and B/BMSY) showed that most of the species (seven) are fully exploited, whereas two and one species were found under- and over-exploited, respectively. Excessive juveniles (Lmean/Lopt and Lc/Lc_opt&amp;lt; 0.90) in catches were observed in the case of Paranibea semiluctuosa. A sufficient number of larger individuals (L95th/Linf&amp;lt; 0.90) in the population were lacking in the case of Johnius belangerii and Otoithes ruber. However, the study indicated a gradual improvement in stock status for most of the species over previous estimates, which can be attributed to the diversion of trawl fishing efforts towards the pelagic realm.

Stock Assessment of Six Sciaenidae Species in the Bay of Bengal, Bangladesh Water Using a Length-Based Bayesian Biomass (LBB) Method

Six most abundant and commercially valuable croakers (Sciaenidae) stocks in the coastal water of Bangladesh were evaluated using a length-based Bayesian Biomass (LBB) approach. The ratios B/B0 (current relative biomass) were smaller than the BMSY/B0 in five of the six stocks. For the six estimated populations, two (Otolithes ruber and Pterotolithus maculatus) are grossly overfished, one (Otolithoides pama) is overfished, two (Johnius belangerii and Panna heterolepis) are slightly overfished, and only donkey croaker (Pennahia anea) is in the healthy (B/B0 &gt; BMSY/B0) status. Furthermore, the optimal length at first capture (Lc_opt) was higher than the length at first capture (Lc) in four populations, indicating growth overfishing, suggesting that increasing mesh size would benefit the catch and biomass. Findings from the present study confirm the declining trend of fisheries resources, particularly the croaker species in the BoB, Bangladesh coastal water. Management strategies (such as effort control, choosing the appropriate mesh size, total allowable catch limit, identify and enhance protection of the feeding, breeding, and nursery ground, etc.) should be taken for the sustainable management and recovery of the country’s marine fishing resources, particularly the valuable croaker species.

Trophic Niche Partitioning of Five Sciaenidae Species Sampled in Zhoushan Archipelago Waters via Stable Isotope Analysis

Sciaenid fishes are usually associated with large freshwater inputs and are the most important economic fish on the coastal shelf off mainland China. To compare the differences in ecological niche and resource sharing among different populations of Sciaenidae species, we collected samples of Larimichthys polyactis, Collichthys lucidus, Johnius belangerii, Nibea albiflora, and Miichthys miiuy from Zhoushan Archipelago waters from 2019 to 2021 and investigated the carbon and nitrogen isotopic values in muscle tissues, the contribution of each food resource, and trophic niche widths and overlaps. Significant differences were observed in both isotopes in the muscles of the five Sciaenid species. Zooplankton was a key food resource for all Sciaenid species. In addition to zooplankton, J. belangerii, N. albiflora, and M. miiuy also fed on benthos organisms. C. lucidus presented a wide trophic niche width and had extensive habitat use. The trophic niche occupied by N. albiflora and M. miiuy was narrow; they presented a high trophic level, with a high degree of trophic niche overlap. This study showed that sciaenid fishes have overlapping trophic niches due to their common feeding on zooplankton, and differences in body size, migration, habitat, and feeding choices led to the reasonable sharing of resources among the five sciaenid fishes, allowing the coexistence of these species.

A Comparison of Fish Diversity in Rocky Reef Habitats by Multi-Mesh Gillnets and Environmental DNA Metabarcoding

This study was undertaken in order to explore the practical effectiveness of the environmental DNA (eDNA) metabarcoding approach in evaluating fish composition and diversity in a high heterogeneous rocky reef habitat. We assessed the fish composition and diversity characteristics of the rocky reef habitat at Dachen Islands, Taizhou and the Zhejiang Province in China in November 2020 by comparing two methods: multi-mesh gillnets and eDNA. A comparative analysis was carried out on the fish composition and diversity characteristics gained under the two methods by using taxonomy, ecotypes and diversity indices. The results showed that there were 28 species of fish collected through gillnets, distributed under 24 genera, 19 families, 6 orders and one class. Among them, 4, 18, and 6 species of near-surface, near groundfish and groundfish were found, respectively, with Thryssa mystax, Johnius belangerii, and Sebastiscus marmoratus being the dominant species in each water layer. A total of 81 species of fish detected by eDNA metabarcoding belonging to 67 genera, 46 families, 15 orders and 2 classes. The near-surface, near groundfish and groundfish species were 17, 42, and 22, with Thryssa vitrirostris, Benthosema pterotum, Harpadon nehereus, and Dasyatis akajei being the dominant species in each water layer. Twenty species (71.4%) and 41 species (50.6%) of reef fish were counted by gillnets and eDNA, respectively. The results showed that multi-mesh gillnets can accurately obtain information on fish composition in rocky reef habitats, but with some selectivity. The eDNA technology can detect species not collected by gillnets, but the number of species detected in areas with fast water velocity is significantly less than other eDNA stations where the water velocity is slow. In summary, the combination of traditional nets and eDNA will provide more information on taxonomic diversity and population biomass, transforming natural resource management and ecological studies of fish communities on a larger spatial and temporal scale.

Catch rates of marine fish species from Shatt Al- Basrah Canal, Southern Iraq

Monthly fish samples were collected from one location at Shatt Al- Basrah Canal from July 2008 to June 2009, using coastal seine net of dimensions 80 m length and 8 m height with a mesh size 10×10 mm. Water temperature, salinity and water transparency were measured. Fishes were identified in the laboratory and total lengths and weights were measured. Catch per unit of effort was estimated for 22 species collected during the sampling period. The a biotic factors exhibited monthly fluctuations, especially in salinity and water temperature. The water temperatures were varied between 12 and 31.5 ºC, and the range of salinity gradient was 5.5-47.5 ppt., however the water transparency showed less variation (37.1-61 cm). Catch per unit of effort found to be zero in December, while the highest catch rate was 39.9 kg / h for Liza subviridis during July and the lowest was 0.02 kg / h for many species during several months. Basing on average as total, the highest average of catch rate was 5.89 kg / h for Liza subviridis, followed by 2.96 kg / h for Liza klunzingeri, while the lowest was 0.14 kg / h for Brachirus orientalis. The two mugilid species Liza subviridis and Liza klunzingeri) consisted 69 % of the overall catch rate and 75 % of the commercial catch rate. The catch rate of Johnius belangerii showed the highest significant positive correlation coefficient (0.72) with temperature, however highest non significant negative correlation was -0.37 for Sillago arabica. For salinity, the results revealed that the highest significant positive correlation was 0.74 with the catch rate of Johnius belangerii and thehighest significant negative correlation (-0.54) with Sillago sihama. The correlations with water transparency showed that the highest significant positive correlation was 0.66 with Acanthopagrus latus and highest non significant negative correlation (-0.39) with Sillago arabica.

Length-based indicators for the sustainability of small-scale fisheries in the Northern Bay of Bengal Coast, Bangladesh

The small-scale fisheries in the northern Bay of Bengal coast of Bangladesh have been suffering due to an uncontrolled expansion of the fishing effort. Given this, it is important for all stakeholders to understand the current stocks’ status and their response to the present degree of removal. This study used two different methodological approaches to assess six commercially important fish species’ stock status from this coast with fisheries representative length–frequencydata: a length-based Bayesian biomass estimation method (LBB) for relative fishing mortality and stock biomass, and Froese’s length-based indicators (LBIs) for the sustainability of the fisheries. The present findings revealed that the biomass of Bregmaceros mcclellandi, Escualosa thoracata, Ilisha filigera, Johnius belangerii and Coilia dussumieri was below the target reference points (B/BMSY < 1 in LBB and SB < SBtarget in LBIs), suggesting overfished status of those fisheries. The biomass of Megalaspis cordyla, on the other hand, was above the threshold level (B/BMSY=1.1 in LBB &SB > 0.4SBtarget in LBIs). Depending on the outputs, this study recommended not to catch fish with lengths equal or smaller than the length at first sexual maturity to avoid growth overfishing, exclude the mega-spawners (length >Lopt+10% of Lopt) from the catch for preventing recruitment overfishing, and bring the fishing mortality back to the sustainable level (F=M) by reducing the existing number of boats to its half for fisheries long-term survivability.

Trophic relationships among fourteen native and non-native fish species in the Shatt Al-Arab River, Iraq

The present study objectified to evaluate the trophic relationships among 14 fish species (10 natives and 4 non-natives) in the Shatt Al-Arab River, considering the trophic niche breadth and the diet overlaps of the species. The food items in the stomach of each species are determined by adopting the index of relative importance (IRI). The dietary analysis revealed a total of 12 types of major food items consumed (which represent &gt;10% IRI). Two species (Oreochromis aureus and Cptodon zillii) were herbivores consumed mostly macrophytes, algae and diatoms. Four species (Planiliza abu, P. klunzengeri, P. subviridis and Osteomugil speigleri) were herbivores mainly fed on diatoms, macrophytes, detritus and algae. Three species (Carasobarbus luteus, Carassius auratus and Cyprinus carpio) were omnivores mostly consumed macrophytes, detritus, diatoms and algae. Two species (Tenualosa illisha and Nematalosa nasus) were filter feeders fed largely on zooplankton, algae, detritus and macrophytes. Three species (Acanthopagrus arabicus, Johnius belangerii and J. dussumeiri) were carnivores mainly preyed on shrimps, crabs and fish. Levin’s index diet breadth analyses divided the studied fish species into three categories; two species with high specialization, five species with low specialization, and seven species with generalization feeders. The dietary composition of fish species exhibited 62 diet overlaps as indicated by the Jaccard index, eight of them high, 36 moderate and 18 low overlaps. Only J. dussumeiri and J. belangerii have no diet overlap with other species. Overall, the study demonstrates that most trophic overlaps between species were moderate, but high degree overlap was between the native species (C. luteus) and invading species (C. auratus) and therefore strengthen earlier conclusions regarding interspecific competition between these two species.

Evaluating Impacts of Trophic Interactions on the Effectiveness of Single-Species Fisheries Management

Single-species fisheries management (SSFM) is applied to many fisheries ecosystems around the world. The associated ecological impacts are usually not well understood due to the lack of considering trophic interactions among species in the ecosystem. This impedes the implementation of SSFM in an ecosystem context and reduces our ability to understand the possible ecological impacts of fishing activities. This study focuses on two economically important species in the Jiaozhou Bay, China: the short-lived, fast-growing, and relatively abundant Japanese mantis shrimp (Oratosquilla oratoria) and the long-lived, slow-growing, and less abundant Korean rockfish (Sebastes schlegelii). We evaluated how varying trophic interactions influenced O. oratoria and S. schlegelii (i.e., target-species) who were managed under constant fishing pressure. The increase of fishing pressure to other species (i.e., non-target species) was beneficial to O. oratoria and S. schlegelii. O. oratoria was more sensitive to the decrease of fishing pressure to other species. The predation mortality of age-0 O. oratoria increased with the increased fishing pressure to other species. The predation mortality of age-1 O. oratoria and age-0 S. schlegelii had negative relationships with the fishing pressure to other species. Age-1 S. schlegelii seemed not to be sensitive to the changes in trophic interactions. The predation mortality of O. oratoria and S. schlegelii had bigger changes than the starvation mortality after fishing changed. It suggested the prey-predator relationship had a bigger impact than the food competition. The increase of high-trophic-level fish Johnius belangerii fishery positively impacted O. oratoria, but negatively impacted S. schlegelii. S. schlegelii was more sensitive to the changes of the low-trophic-level fish Pholis fangi fishery. Given the complex dynamics of ecosystems, this study highlights the importance of species-specific responses of fishes to shifting trophic interactions in fisheries management.

Prey decline leads to diet shift in the largest population of Indo-Pacific humpback dolphins?

The Pearl River Delta (PRD) region on the southeast coast of China has long been known as a highly productive fishing ground. Since the late 1980s, fishing pressure in the PRD has been intense, which warrants concerns of potential fishery-related impacts on the food resources and foraging ecology of apex marine predators in this region, such as the Indo-Pacific humpback dolphin (Sousa chinensis). In this study, we examined 54 stomachs with food remains, collected from beached carcasses of humpback dolphins recovered during fifteen years between 2003 and 2017. The 6043 identified prey items represent 62 teleost taxa, primarily small estuarine fish, but also larger reef fish. The dolphins appear to be opportunistic foragers, hunting across the water-column, with preference for shoaling and meaty fishes (e.g. Collichthys lucidus IRI% = 38.6%, Johnius belangerii IRI% = 23.1%, Mugil cephalus IRI% = 14.0%). Our findings suggest a dietary shift in recent years, from primarily demersal (as previously reported) to greater intake of neritic and pelagic fish. Dolphin foraging group size has decreased in recent years, which corresponds with declining size and numbers of prey items retrieved from dolphin stomachs. We suggest that these are indicators of declining food resources. Faced with a shortage of preferred prey, humpback dolphins may have broadened their dietary spectrum to maintain their daily energy intake, while their foraging group size decreased in response to the altered tradeoff between the costs and benefits of group foraging.

Evaluating the effect of input variables on quantifying the spatial distribution of croaker Johnius belangerii in Haizhou Bay, China

Evaluating the effect of input variables on quantifying the spatial distribution of croaker Johnius belangerii in Haizhou Bay, China

Heavy metals risk assessment in fish species (Johnius Belangerii (C) and Cynoglossus Arel) in Musa Estuary, Persian Gulf

In this study the possible health effects of consumption of benthopelagic (Johnius Belangerii (C); JB) and demersal (Cynoglossus Arel; CA) fishes were evaluated. These fish species living in the Musa estuary (the biggest estuary in the south of Iran and in the northern coastline of Persian Gulf) are likely to be polluted with Hg, V, Ni and Tl. The food frequency questionnaire (FFQ) was used to estimate fish intakes in the residents of Mahshahr city. Also, heavy metal concentrations were determined in fishes and compared with the maximum permissible levels (MPLs). The bioaccumulation factor (BAF) showed high bioaccumulation ability for Hg and Tl in both fish spices. The ratio of TDI/EDI showed the importance of the health hazard by both fish consumption. Also, Hg and Tl in fishes had a higher calculated target hazard quotient (THQ) than the limits. Regarding with the high possibility of serious health concerns associated with Hg and Tl contamination in the Musa estuary, it is suggested to do appropriate and urgent actions by the governors.

Concentration of Heavy Metals (Pb and Cu) in Alepes vari and Johnius belangerii from Musi River Estuary, Banyuasin District, South Sumatra

Agustriani F, Purwiyanto AIS, Putri WAE, Fauziyah. 2019. Concentration of heavy metals (Pb and Cu) in alepes vari and johnius belangerii from musi river estuary, Banyuasin district, South Sumatra. Jurnal Lahan Suboptimal: Journal of Suboptimal Lands. 8(2):213-219. The Musi river estuary plays an important role as one of the fishing grounds. The high activity in the musi estuary has an impact on the ecosystems in this region, including the negative impact in the form of ecosystem changes caused by heavy metals. The aim of this study was to determine the concentrations of heavy metals (Pb and Cu) in Alepesvariand Johniusbelangerii in the Musi river estuary. Fish were obtained from fishermen who used the Gillnet Millennium (Ply) gear in July 2018 and were analyzed using the Atomic Absorption Spectrophotometer (AAS). The results showed that the concentration of Pb in J. belangerii was greater than A. vari, but the concentration of Cu in A. vari was greater than in J. belangerii. Concentration of Pb has exceeded the limit for safe consumption based on National Agency of Drug and Food Control.

Biodiversity of fish resources in Sungsang Estuaries of South Sumatra

The purpose of this study was to assess the fish biodiversity of Sungsang estuaries in South Sumatra. The species diversity, evenness, dominance, degree of similarity, and composition of fish communities as well as some physicochemical conditions were analyzed in order to establish the baseline data inventory of Sungsang estuaries. The results show that all of the physico-chemical parameters were in good condition for fish sustainability. Forty-eight (48) species of fish belonging to 29 families of freshwater, brackish water and marine sources were encountered in the water bodies. Johnius belangerii, Johnius amblycephalus and Setipinna taty were species with a relatively high abundance, but the appearance frequency of these species was high, medium and low, respectively. The value of the Shannon’s diversity index for fish resources was classified as moderate (H’=1.477-2.708). The index value of evenness was classified as high (J’= 0.616 – 0.876), while the index value of dominance was classified as low (D = 0.097 – 0.382). This result indicate that the species diversity was good enough, the species spread was evenly distributed, that there was a stable community structure and no domination.