Rastrelliger Brachysoma Research Articles

KARAKTERISTIK BIOLOGI DAN LAJU EKSPLOITASI IKAN PELAGIS KECIL DI PERAIRAN UTARA JAWA

Aktivitas perikanan di perairan utara Jawa didominasi perikanan pelagis kecil yang memegang peranan penting dalam pembangunan perikanan di Indonesia. Meskipun secara nasional potensi ikan pelagis kecil belum dimanfaatkan secara optimal, namun di beberapa wilayah perairan tingkat pemanfaatannya telah melampaui potensi lestari. Laju eksploitasi menjadi parameter kunci dalam menggambarkan tingkat pemanfaatan sumberdaya ikan pelagis kecil di suatu perairan. Penelitian ini bertujuan untuk mengetahui karakteristik biologi dan laju eksploitasi pada beberapa jenis ikan yang menjadi hasil tangkapan utama pada perikanan pelagis di perairan utara Jawa. Sebanyak enam jenis ikan pelagis kecil (ikan selar bentong, japuh, kembung perempuan, selar kuning, selar komo, dan tembang) yang tertangkap di perairan utara Jawa telah mengalami over eksploitasi. Secara umum, karakteristik biologi masing-masing ikan telah menunjukkan bahwa sebagian besar ikan pelagis kecil yang tertangkap belum mencapai ukuran pertama kali matang gonad. Selain itu, ikan kembung, selar, dan tembang dikategorikan berpotensi resiko tinggi terhadap penangkapan, diduga dari parameter ukuran ikan dan jumlah alat tangkap yang dioperasikan.

Individual assignment and mixed-stock analysis of short mackerel (Rastrelliger brachysoma) in the Inner and Eastern Gulf of Thailand: Contrast migratory behavior among the fishery stocks

Short mackerel (Rastrelliger brachysoma) is a pelagic-neritic and the most economically important fish in Thailand with the value reached 190 M USD in 2013. The short mackerel is however classified as data deficient in IUCN Red List. In particular, short mackerel resource in the Gulf of Thailand is recently drastically decreased due to overfishing. In this study, we applied the individual assignment (IA) and mixed-stock analysis (MSA) based on microsatellite loci to short mackerel fishery catches in the Inner and Eastern Gulf of Thailand. We found contrast migratory behavior among the fishery stocks. The majority (55.51%) of fully grown mackerel caught from the Inner Gulf of Thailand was sedentary mackerel in the fishing area, Samut Songkhram spawning ground. In contrast, almost all fully grown short mackerel (85.58%) caught from Eastern Gulf of Thailand were migrant from Southern Gulf of Thailand, Pattani spawning ground (>600 km of migration distance). This information strongly indicated that distinct management strategies are required to sustain fishery catches in the two large fishing areas. The seasonal closure on significant spawning grounds of short mackerel, including limit the number of vessels and the ban of destructive fishing gears are highly recommended for fishery management in the Gulf of Thailand.

Habitat Suitability Mapping of Rastrelliger Brachysoma Using MODIS Image in WPP 711

Important factors that needs to be understood in the management of fishery resources is fish habitat. Fish habitat is an ideal water conditions of a fish species to spawn, breed, feed and grow into adults. Distribution of fish habitat can be approach using variety method, such Habitat Suitability/Species Distribution Modeling. Remote sensing analysis is effective method in providing daily oceanography information. Modis is Remote sensing imagery can be used for modeling Rastrelliger brachysoma fish habitat. Date acquired MODIS image at 28 March 2015, depend on existing field data. The results indicate that, the highest probability of Rastrelliger brachysoma fish habitat location in WPP 711 are in the middle waters of the WPP border between the deep sea of Indonesia and the Pacific Ocean. The lowest probability value for habitat of Rastrelliger brachysoma fish is in the southern shallow waters of Bangka Belitung island which is around 0.1-0.25.

Nearshore Fish Aggregating Devices Show Positive Outcomes for Sustainable Fisheries Development in Timor-Leste

Capture fisheries in small island developing states have the capacity to increase access to vital micronutrient-rich food to tackle malnutrition, but when fishers are restricted to nearshore habitats by limited capacity (boats, engines, fishing gear), fisheries production can be low. This is the case of coastal Timor-Leste, where some of the world’s most diverse coral reefs are juxtaposed with one of the world’s most undernourished populations. In these settings, interventions that have successfully improved livelihoods from fishing and reduced threats to biodiversity are rare. Elsewhere in the Pacific, nearshore anchored fish aggregation devices (FADs) have shown success in improving catch rates by making pelagic stocks more accessible to small-scale fishers. Here we test the effects of FADs at increasing capture fish production, by deploying 8 experimental FADs at 4 sites around the country and recorded catch and effort data from FAD and non-FAD fishing trips. We assess the effects of FADs on catch rates and catch assemblage and the rate of 100% return on investment (RoI). The average longevity of FADs was 11 months. Results show a significant positive effect of FADs on catch rates when controlling for random site variation, with FADs paying for themselves in ~5 months or less at 3 out of 4 sites. Across all sites and fishing types, 63 species were identified, but FAD catches significantly reduced overall assemblage diversity, with 3 species (Amblygaster sirm, Decapterus macarellus, Rastrelliger brachysoma) representing 96% of the catch. Despite the relatively short longevity of FADs deployed in Timor-Leste, the fast RoI seen at most sites indicates that FADs are effective in providing livelihood benefits in certain locations. Catch rates were highest where fishers were specialised, invested in FAD fishing, and formed catch sharing groups with access rights to specific FADs. National level investment into a FAD programme by the government could realistically increase overall fish production in the country, thereby improving availability of micronutrient rich fish to combat malnutrition. A deployment program should be coupled with capacity building around group formation and defining access rights to ensure equitable community benefits.

Immunoreactivity of estrogen receptor alpha in brain and ovary of the short mackerel Rastrelliger brachysoma (Bleeker, 1851)

The reproductive physiology concerning the gonadotropin hormone (GTH) and its downstream target estrogen receptor alpha (ERα) is not well understood in the short mackerel Rastrelliger brachysoma, an economically important marine fish in Thailand. In this study, we tested the hypothesis that the expression of both GTH and ERα in the brain and ovary of R. brachysoma was as reported in other fish species. By applying immunohistochemical techniques, we identified the distribution of ERα-immunoreactive (ir) neurons in the brain and ovary of wild female R. brachysoma during the spawning season along with the distribution of GTHs-ir cells in the ovary. The nucleus lateralis tuberis in the diencephalon had a high number of ERα-ir neurons. In the mesencephalon, dense ERα-ir neuronal fibers were mainly found in the mesencephalic cells, stratum opticum, stratum fibrosum et griseum superficiale and stratum album centrale. Both the valvula and corpus cerebelli in the metencephalon contained ERα-ir neurons in granular and Purkinje cell layers as well as the molecular layer. The ERα-ir neurons were also observed in the medulla oblongata. In the ovary, weak ERα and moderate GTHs immunoreactivities were observed in follicular cells of oocytes in early and late vitellogenic stages. This information provides baseline data required to understand not only the activity of estrogen (E2) on the brain but also the regulatory mechanism of the hypothalamo-pituitary-ovarian axis of R. brachysoma.

POPULATION DYNAMIC AND SPAWNING POTENTIAL RATIO OF SHORT MACKEREL (Rastrelliger brachysoma Bleeker, 1851) IN THE NORTHERN COAST OF JAVA

Short mackerel fish (Rastrelliger brachysoma) is one of small pelagic fish mostly exploited by mini purse seine fishing gear. Exploitation of short mackerel by mini purse seine has an increasing trend every year and suspected to have negative impacts. One of the negative impact is the decrease of fish abundance, so it is necessary to carry out population dynamics and Spawning Potential Ratio (SPR) studies through length-based approach to provide exploitation indicator as biology reference point. The result of length-weight relationship analysis shows that the growth pattern (b = 2.3483) is negative allometry. The estimated length at first capture and its first sexual maturity analysis shows that the value of length at first capture (Lc = 15.4 cm FL) is greater than the length at first sexual maturity (Lm = 15.21 cm FL). The estimated maximum length (L∞) is 21.05 cm FL with growth rates (K) is 1.01 year-1 and t0 at -0.177 years. The estimated total mortality (Z) was 5.48 year-1, natural mortality (M) was 2.02 year-1 and fishing mortality (F) was 3.46 year-1. The predicted exploitation rate (E) is 0.63 which higher than the optimum value (E = 0.5). The estimated length-based SPR (LB-SPR) of 30% (SPR > 20% or above limit) means that short mackerel fishing activity has full exploitation.

Histological Analysis Gonad Maturity Level of Rastrelliger brachysoma (Bleeker, 1851) in Lekok Waters, Pasuruan

Rastrelliger brachysoma is an important economic fish for coastal communities. Rastrelliger brachysoma included in the red-list of species based on the IUCN of 2017 so the utilization of this species should be taken into account. Excessive and continuous utilization causes this species to dwindle. Fish catches of various sizes and unknown levels of gonad maturity of these fish resulted in female bloating becomes less and feared will be increasingly difficult to find in the water. Research on gonad girth level needs to be done to find out whether the fish catch is indeed feasible to be caught or not capture yet (in this case have experienced mature gonads). The results showed Rastrelliger brachysoma matured gonad on average length of 17.03 cm with sex ratio of 238 ± 20,074 for female fish and the amount of 179 ± 25,408 for male fish. Histologic analysis showed that Rastrelliger brachysoma was at maturity level of gonad I, II, III, IV and V while morphological analysis showed Rastrelliger brachysoma was in maturity level of gonad I, II, III and IV.

Preliminary quantitative microbial risk assessment of pathogenic Vibrio parahaemolyticus in short mackerel in Malaysia

A preliminary quantitative microbial risk assessment of Vibrio parahaemolyticus in short mackerels was conducted from retail to consumption levels in a stochastic model. The key uncertainties included of growth during retail display, transportation duration, and microbial log reduction after the preparation and cooking steps were taken into consideration in the exposure assessment. Human health risk associated with the consumption of short mackerels contaminated with pathogenic V. parahaemolyticus was predicted by fitting the number of cells ingested into a Beta-Poisson dose-response model. Advanced sensitivity analysis was performed to determine the predictive factors most highly correlated with risk illness. The model evaluated through Monte Carlo simulation revealed an estimated number of illness ranged from 1.34 × 10−4 to 12.80 with an average incidence of 2.07 cases per annum. The rates per 100,000 population were predicted at 6.53 × 10−3 cases per year in Malaysia. In this study, the development of quantitative microbial risk assessment of V. parahaemolyticus in short mackerels provides valuable information such as the probability of illness associated with the consumption of short mackerels and the primary factor quantitatively important for risk illness.

Prevalence, site of infection, and differentiating oocytes of the cymothoid isopod, Norileca indica (Milne Edwards, 1840) from its infected short mackerel, Rastrelliger brachysoma, in the Upper Gulf of Thailand

Norileca indica, a cymothoid isopod crustacean, is an obligate parasite infecting marine fishes in tropical areas. This study attempted to investigate the prevalence, site of infection and distinct stages of oogenesis of this parasitic isopod obtained from short mackerel (Rastrelliger bachysoma). All N. indica samples were collected and processed through histological techniques. N. indica showed higher prevalence during the dry season than the rainy season and its parasitic infections were more prevalent in the female R. brachysoma (60% prevalence) compared to males. Two distinct sites of N. indica attachment on the host (infection sites) including gill and integument were clearly observed. Interestingly, this isopod preferred to attach more on the integument surface than gill, especially in the female R. brachysoma (55% prevalence). Using histological observation, N. indica exhibited asynchronous development of oocyte in the ovary. The oocytes were enclosed by a thin layer of connective and muscular tissues. Three stages of oogenesis can be identified in the ovary: oogonium, primary oocyte, and secondary oocyte. Oogonium located inside the cyst near the germinal epithelium. A large nucleus of oogonium was surrounded by a weak basophilic cytoplasm. Unlike oogonium, multiple nuclei (2 - 3 nuclei) surrounded by basophilic cytoplasm was a key characteristic of the primary oocyte. The secondary oocyte contained spherical yolk granules with multiple layers of follicular cells, which might function to support yolk uptake into the ooplasm. In addition, early embryonic development of N. indica was also observed in this study. Taken together, this finding highlights parasitic prevalence and infection sites of N. indica in short mackerel, as well as a better resolution of its oogenesis, early development and reproductive cycle.

Testicular structure and spermatogenesis of short mackerel, Rastrelliger brachysoma (Bleeker, 1851) in Upper Gulf of Thailand

Testicular structure and spermatogenesis of short mackerel, Rastrelliger brachysoma (Bleeker, 1851) (Teleostei: Scombridae) was first investigated. The testicular parenchyma was a lobular organ, which was classified as an unrestricted spermatogonial type. The classification of spermatogenetic stage could be classified into six stages based on the pattern of chromatin condensation and other characterizations at the light microscopic level. These six stages included the primary and secondary spermatogonium, primary and secondary spermatocyte, spermatid and spermatozoon. The spermatogenesis could also be classified into another four stages based on the nuclear and cytoplasmic characterizations at the ultrastructural level. Spermatogonium was the early germ cell. It underwent a series of mitotic division to reach the primary spermatocyte. Secondary spermatocyte was shown as the heterochromatin surrounding the nuclear membrane, which was rarely seen within seminiferous lobules. Stages during the spermatids differentiation comprised of the early, intermediate and late stages which are under the degree/change of chromatin condensation. Finally, the spermatozoon was revealed as the aquasperm primitive type. It was composed of an oval head without an acrosome, a short mid-piece consisting of two basal bodies (proximal and distal centrioles) and a long flagella tail without lateral fins. The axonemes of classical form with 9+2 microtubules were presented in the flagellum.

Health status in wild and captive short mackerel, Rastrelliger brachysoma from Thailand: Histopathology

Health status in wild and captive short mackerel, Rastrelliger brachysoma from Thailand: Histopathology

Correction to: The sbGnRH-GTH system in the female short mackerel, Rastrelliger brachysoma (Bleeker, 1851), during breeding season: implications for low gamete production in captive broodstock.

The published online version of this article contained outdated Figs.4 and 5. The original article has been corrected.

The sbGnRH-GTH system in the female short mackerel, Rastrelliger brachysoma (Bleeker, 1851), during breeding season: implications for low gamete production in captive broodstock.

The short mackerel (Rastrelliger brachysoma) is one of the most economically important fish in Thailand; it is also a prime candidate for mariculture but unfortunately is plagued by reproductive problems that cause low production of gametes in captivity. An understanding of how the brain, pituitary, and gonad axis (BPG) from the neuroendocrine system are involved in the reproductive activity of wild and captive R. brachysoma should help clarify the situation. In this study, we investigated changes in the sea bream gonadotropin-releasing hormone (sbGnRH)-gonadotropin (GTH) system in the female short mackerel, Rastrelliger brachysoma (Bleeker, 1851), during breeding season. sbGnRH-immunoreactive (ir) cell bodies were detected in the nucleus preopticus-periventricularis including nucleus periventricularis (NPT), nucleus preopticus (Np), and nucleus lateralis tuberis (NLT). Additionally, the sbGnRH-ir fibers protruded into the proximal par distalis (PPD) where GTH (FSH and LH) cells were detected. The number of sbGnRH-ir cell bodies and GTH cells and level of LH mRNA were significantly higher in the breeding season than those in the non-breeding season. Moreover, the number of sbGnRH-ir cell bodies and GTH cells and levels of sbGnRH and GTH (FSH and LH) mRNA were significantly higher in the wild fish than those in the cultured broodstock. It is suggested that the wild fish tended to have better reproductive system than hatchery fishes. This could be related to the endocrinological dysfunction and the reproductive failure in the hatchery condition. Moreover, the changes of all of the hormonal level could potentially be applied to R. brachysoma aquaculture.

APPLICATION OF OZONE-SLURRY ICE COMBINED SYSTEM FOR MAINTAINING THE FRESHNESS OF RED TILAPIA AND SHORT-BODIED MACKEREL DURING COLD STORAGE

Application of ozone combined with the chilling system on preserving fresh fish has obviously brought about more advantages. This study observed the application of an ozone-slurry ice combined system for maintaining the freshness of two different fishes during storage. The fishes used were red tilapia (Oreochromis niloticus) and short-bodied mackerel (Scomberomorus rastrelliger), using ozone and slurry ice. The experimental design used was factorial using a completely randomized design employed with an ozone concentration of 0 ppm and 3.5 ppm with storage times of 0, 4, 8, 12, and 16 days. The parameters observed included: peroxide value (PV), total volatile base nitrogen (TVBN), total viable count (TVC), and a sensory test. The parametric data were analyzed using ANOVA and followed by least significant difference (LSD), whereas the non-parametric data were analyzed using the Kruskal Wallis test followed by multiple comparison tests. Ozone and slurry ice treatment of different concentrations had a significant (p<0.05) effect on the TVBN, the PV, and the TVC. The interaction of ozone and slurry ice provided no significant difference (p>0.05) in both samples.A sensory evaluation in both samples showed good correlation with TVC. This study showed that ozone and slurry ice could maintain the samples freshness during storage.

Length-weight relationship of Rastrelliger brachysoma (Bleeker, 1851) and Rastrelliger faughni Matsui, 1967 from the Andaman Islands, India

This study reports the length–weight relationships (LWRs) of Rastrelliger brachysoma (Bleeker, 1851) and Rastrelliger faughni Matsui, 1967 from Andaman Islands, India. Sample sizes for the two fish species were 78 for R. brachysoma and 57 for R. faughni. Fish collected monthly from Junglighat fish landing center. Fish were captured by commercial ring seine units (mesh size ranging from 2 to 4 cm) between February 2016 and March 2017. LWRs were established as TW = 0.0042TL3.332 (r2 = .989) for R. brachysoma and TW = 0.0096TL3.022 (r2 = .980) for R. faughni.

Prevalence and Antimicrobial Susceptibility of Vibrio parahaemolyticus Isolated from Short Mackerels (Rastrelliger brachysoma) in Malaysia.

Numerous prevalence studies and outbreaks of Vibrio parahaemolyticus infection have been extensively reported in shellfish and crustaceans. Information on the quantitative detection of V. parahaemolyticus in finfish species is limited. In this study, short mackerels (Rastrelliger brachysoma) obtained from different retail marketplaces were monitored with the presence of total and pathogenic strains of V. parahaemolyticus. Out of 130 short mackerel samples, 116 (89.2%) were detected with the presence of total V. parahaemolyticus and microbial loads of total V. parahaemolyticus ranging from <3 to >105 MPN/g. Prevalence of total V. parahaemolyticus was found highest in wet markets (95.2%) followed by minimarkets (89.1%) and hypermarkets (83.3%). Pathogenic V. parahaemolyticus strains (tdh+ and/or trh+) were detected in 16.2% (21 of 130) of short mackerel samples. The density of tdh+ V. parahaemolyticus strains were examined ranging from 3.6 to >105 MPN/g and microbial loads of V. parahaemolyticus strains positive for both tdh and trh were found ranging from 300 to 740 MPN/g. On the other hand, antibiotic susceptibility profiles of V. parahaemolyticus strains isolated from short mackerels were determined through disc diffusion method in this study. Assessment of antimicrobial susceptibility profile of V. parahaemolyticus revealed majority of the isolates were highly susceptible to ampicillin sulbactam, meropenem, ceftazidime, and imipenem, but resistant to penicillin G and ampicillin. Two isolates (2.99%) exhibited the highest multiple antibiotic resistance (MAR) index value of 0.41 which shown resistance to 7 antibiotics. Results of the present study demonstrated that the occurrence of pathogenic V. parahaemolyticus strains in short mackerels and multidrug resistance of V. parahaemolyticus isolates could be a potential public health concerns to the consumer. Furthermore, prevalence data attained from the current study can be further used to develop a microbial risk assessment model to estimate health risks associated with the consumption of short mackerels contaminated with pathogenic V. parahaemolyticus.

Ovarian histology and reproductive health of short mackerel, Rastrelliger brachysoma (Bleeker, 1851), as threatened marine fish in Thailand

Ovarian histology and reproductive health of short mackerel, Rastrelliger brachysoma (Bleeker, 1851), as threatened marine fish in Thailand

Structure and ultrastructure of oogenic stage in short mackerel Rastrelliger brachysoma (Teleostei: Scombidae)

Abstract Introduction: Structure, ultrastructural features and degeneration of oogenesis were first investigated in female Rastrelliger brachysoma as new candidate species for aquaculture by transmission electron microscopy. Materials and Methods: Specimens were naturally collected during the breeding season from Samut Songkhram Province, Thailand. Results: The ultrastructure of female oogenesis was principally divided into five stages based on the nuclear characterization and cytoplasmic organelles; (i) oogonium; (ii) previtellogenic; (iii) lipid and cortical alveolar; (iv) early and (v) late vitellogenic stages. Initially, oogonium was present within cell nest in the epithelial compartment. Its cell was supported by prefollicular cells. The multiple nucleoli in previtellogenic stage, referring to primary growth stage were the first to appear and they were scattered around the peripheral of nuclear membrane with the increasing number of cytoplasmic organelles. Some microvilli of granulosa cell initially protruded into the vitelline envelope. A simple layer of flattened granulosa and theca cells was also observed. The lipid and cortical alveolar stage under secondary growth oocyte was accumulated with two inclusions; the lipid droplets and cortical alveoli in the ooplasm. Another characterization, the increasing of numerous microvilli was also detected in the vitelline envelope. Finally, in the vitellogenic stage, a massive uptake and processing of proteins into yolk platelets due to embedding of the numerous microvilli in the largest vitelline envelope was observed. Oocyte degeneration in R. brachysoma was novel found especially oogonial and previtellogenic stages. Conclusion: Five oogenic stages of this fish are found with the changing of the arrangement of nucleus, cytoplasmic organelles and follicular complex, which will be applied to further studies.

LAJU EKSPLOITASI SUMBER DAYA IKAN YANG TERTANGKAP PUKAT CINCIN DI SELAT SUNDA (Exploitation Rate of Fisheries Resources which Caught by Purse seine in Sunda Strait)

ABSTRACTSunda Strait is waters which have great fishery potential in Indonesia. Catches of the Sunda Strait were landed in Pandeglang Regency, one of which is in the Coastal Fishing Port (PPP) Labuan. Purse seine is fishing gear with the highest production in Sunda Strait. Species targets of purse seine are Fringescale sardinella, Mackerel, Short mackerel, Indian mackerel, Kawakawa, and Indian scad. The high price of the fish lead purse seine operation continuously. Increasing purse seine operation can lead to the scarcity fishery resources. Therefore, a study about fish exploitation rate is needed to know the utilization status. The purpose of this study was to evaluate the exploitation rate of multispesies fisheries which caught by purse seine in Sunda Strait based on catch data landed data in PPP Labuan. This study used the ELEFAN I methods and Pauly formula. The result showed that the exploitation rate of fish resources for female and male fringescale sardinella are 0,79 and 0,70; Island mackerel are 0,78 and 0,60; short mackerel are 0,85 and 0,88; Indian mackerel are 0,80 and 0,83; kawakawa are 0,95 and 0,90; Indian scad are 0,75 and 0,62. Nowadays, all fish which caught by purse seine in the Sunda Strait has been indicated to over-exploitation.Keywords: exploitation rate, pelagic fish, purse seine, Sunda strait------ABSTRAKSelat Sunda merupakan perairan yang memiliki potensi perikanan yang cukup besar di Indonesia. Hasil tangkapan ikan dari Selat Sunda didaratkan di Kabupaten Pandeglang, salah satunya adalah di Pelabuhan Perikanan Pantai (PPP) Labuan. Pukat cincin merupakan alat tangkap dengan produksi paling banyak di Selat Sunda. Spesies yang merupakan target tangkapan pukat cincin yaitu tembang, kembung, kembung perempuan, kembung laki-laki, tongkol, dan layang. Harga jual ikan yang tinggi menyebabkan pengoperasian pukat cincin terus ditingkatkan. Pengoperasian pukat cincin yang terus meningkat dapat menyebabkan kelangkaan terhadap sumber daya perikanan. Oleh karena itu, perlu dilakukan kajian mengenai laju eksploitasi sumber daya ikan agar diketahui status pemanfaatannya. Tujuan penelitian ini adalah untuk mengevaluasi laju eksploitasi multispesies yang tertangkap pukat cincin di Selat Sunda berdasarkan data tangkapan yang didaratkan di PPP Labuan. Pada penelitian ini digunakan metode ELEFAN I dan rumus Pauly. Hasil analisis menunjukkan bahwa laju eksploitasi sumber daya ikan berturut-turut betina dan jantan spesies tembang sebesar 0,79 dan 0,70; kembung 0,78 dan 0,60; kembung laki-laki 0,85 dan 0,88; kembung perempuan 0,80 dan 0,83; tongkol 0,95 dan 0,90; layang 0,75 dan 0,62. Saat ini kondisi semua ikan hasil tangkapan dominan pukat cincin di Selat Sunda telah mengalami tangkap lebih.Kata kunci: ikan pelagis, pukat cincin, laju eksploitasi, Selat Sunda

Rapid and cost-effective molecular identification of the three mackerel species of the genus Rastrelliger (Perciformes: Scombridae) using PCR-RFLP analysis

The three mackerel species, Rastrelliger kanagurta, Rastrelliger brachysoma, and Rastrelliger faughni, co-occur in the central part of the Indo-West Pacific Ocean, and together represent important fisheries resources. However, they have sometimes been collectively referred to as “Rastrelliger spp.” in the fisheries statistics, owing to their morphological similarity. Therefore, species-specific data on landings, effort, and population status are lacking, undermining the appropriate resource management. The present study provides a rapid and cost-effective method based on polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis to distinguish the three species. Digestion of the PCR products of 1247 base pairs of mitochondrial DNA encompassing the complete sequence of cytochrome b gene using two restriction enzymes yielded diagnostic restriction patterns for the three species, thereby enabling accurate identification.