Priacanthus Hamrur Research Articles

UTILIZATION OF GILLNET CATCHES FISHERMEN OF MATANG RAYEUK VILLAGE, NUSANTARA FISHERY PORT, EAST ACEH

The purpose of this community service is to determine the composition of the main and by-catch of gill nets and the size of the catch. This community service was carried out during April 2023 at PPN Idi Rayeuk, Matang Rayeuk Pedawa Puntong Village, East Aceh Regency. The data collection method used was obtained from primary data (surveys and interviews) which included the type, quantity, size, and weight of the gill net catch and secondary data can be obtained from scientific references books, journals, theses and dissertations). The data analysis used was the analysis of the composition of the catch and the analysis of the size of the catch. The results of the community service showed that the composition of the main catch of the gill net at a mesh size of 1¼ inches was tembang fish, at a mesh size of 2 inches was ribbon fish and at a mesh size of 3 inches was kapasan/kerot-kerot and kwee fish. By-catch with a net size of 1¼ inches is jackfruit seed fish (upeneus moluccensis), kurisi (nempiterus hexodon), petek (leiognathus equulus), yellow trevally (Atule mate), saurida (Saurida undosquamis), swanggi (Priacanthus hamrur), next (Psettodes erumei), parang-parang (chirocentrus dorab), tetengkek (megalaspis cordyla). ) and layur (trichiurus Sp.A). Next, at a mesh size of 2 inches, namely talang fish (scomberoides tala), diles (johnius carouna), petek (leiognathus equulus), moon (Megalops cyprinoides), machete (chirocentrus dorab), jackfruit (upeneus moluccensis), kurisi (nempiterus hexodon), kwee (carangoides armatus), tetengkek (megalaspis cordyla), gerot-gerot ( Pomadasys kaakan), kerong-kerong (Terapon Jarbua), and alu-alu (Sphyraena genie). Then at the 3 inch mesh size, namely the kapasan/kerot-kerot fish (Pomadasys argenteus), talang (scomberoides tala), petek (leiognathus equulus), kuro (Polydacctylus microstoma), diles (johnius carouna), parang-parang (chirocentrus dorab), mackerel (Scomberomorus Commerson), kapas (Gerres filamentosus), and tetengkek (megalaspis cordyla). The catch at the 1¼ and 2 inch mesh sizes is said to be not yet suitable for catching, while the 3 inch mesh size is said to be suitable for catching.

Utilizing Bullseye fish processing frame waste to produce edible proteins and quality assessment of the recovered proteins.

The aim of the study was to utilize the waste generated from Bullseye (Priacanthus hamrur) fish processing to recuperate proteins. Considering the cost-effectiveness, versatility, and color improvement after the pH shift method, proteins from this waste were extracted by the pH shift method using hydrochloric acid and sodium hydroxide. The properties of extracted proteins were studied in detail. During the protein solubility measurement, maximum solubilization was found at pH 3.0 (13.10mg/mL) on the acidic side and pH 11.0 (14.25mg/mL) on the alkaline side with a total yield of 51.62 ± 0.23 and 45.42 ± 0.29 (%), respectively. The process variables tested in this study showed a significant effect on protein solubility (p < 0.05). The protein content of the isolates extracted from the waste was 23.80 ± 0.49 and 22.48 ± 0.39% for acid and alkali processed isolates, which was significantly higher than the mince (19.46 ± 0.67%). pH shift processing of Bullseye proteins caused a significant reduction in its pigments, lipids, and myoglobin content (p < 0.05). Proteins extracted using alkali had significantly higher values for foaming stability, water holding capacity, and emulsion capacity than proteins extracted using acid. An overall assessment indicated that protein isolates obtained using alkali extraction were better in terms of textural attributes, gelling ability, and amino acid profile than protein isolates extracted using the acid process.

Effect of pomegranate and orange peel extracts on the quality of fish ham under frozen storage

Aim: The objective of the present study was to evaluate the effect of pomegranate and orange peel crude extract on fish ham quality in terms of biochemical, microbiological, and sensory parameters under cold storage (-18±2oC). Methodology: The crude extracts were extracted from dry powder of orange and pomegranate peel using absolute ethanol as solvents. The extracts were standardized in the mackerel cooked meat model system to determine the concentration for the final products. Fish ham was prepared using red meat of tuna (Thunnus albacares) and white meat of bull’s eye fish (Priacanthus hamrur). The prepared fish ham was treated with 2000 mg l-1 of pomegranate and orange peel extracts and stored under frozen conditions. Results: The results obtained were compared with a control sample containing synthetic antioxidant Butylated hydroxyanisole. The results showed that pomegranate and orange peel extracts significantly (p &lt; 0.05) reduced the lipid oxidation and microbial activity. The results of biochemical studies revealed that there was a considerable increase in the quality parameter in all treated samples. The fish ham treated with pomegranate peel extract, orange peel extracts showed formation slower primary, secondary oxidation products and breakdown of nitrogenous compounds. Interpretation: Pomegranate and orange peel can be a substitute for synthetic antioxidants. These findings suggest that the pomegranate and orange peel serve as a choice to use as a food antioxidant for extending the shelf life of fish fishery products.

Species composition and spatio-temporal variation of bycatch from mid-water trawlers operating in the Arabian Sea along north-west coast of India

The mid-water multiday trawl fishery along the north-west coast of India generally targets adult largehead hairtail, Trichiurus lepturus. Bycatch landed by the commercial mid-water multiday trawlers operated from Veraval harbor during August 2017–December 2019 was investigated by analyzing catch composition with respect to its spatial and temporal patterns. A total of 834 bycatch sample observations from mid-water trawl fishery were examined. Bycatch comprises of 123 species and account for 53.36% of the total catch. Highest composition in bycatch comprises of teleosts (62.09%), cephalopods (35.88%), crustaceans (1.47%) and elasmobranchs (0.56%) respectively. Uroteuthis duvaucelii, Sepia elliptica, Nemipterus japonicus, Otolithes cuvieri, S. pharaonis, Priacanthus hamrur, Sepiella inermis and Saurida tumbil were the dominant species with high annual average catches; and together contributed 50.30% of total bycatch. Discards formed 6.32% of total catch and consisted of 62 species belonging to 29 families. The most common discards were juveniles of S. tumbil, N. japonicus, Platycephalus indicus, O. cuvieri, Johnius glaucus and T. lepturus. CPUE of bycatch differed significantly between the seasons with the lowest being in summer and highest in post-monsoon period. Minimum bycatch rates were observed in the offshore waters than inshore waters. Endangered, Threatened and Protected (ETP) species listed in CITES as well as IUCN were also observed. The present study revealed that quantities of bycatch landed off northwest coast of India in the Arabian Sea were relatively higher than that landed by mid-water trawlers operating in other parts of the world. Hence the mid-water trawl fishery operating in north-west coast of India and targeting largehead hairtail needs to be closely monitored to mitigate and reduce the quantity of bycatch landed by them.

Studies on the public health importance of infestation of Ostracoda Vargula tsujii (Myodocopa: Cypridinidae) in some marine food fishes off Pamban, Southeast coast of India – A case study

The present study was the first attempt to investigate the public health importance of infestation of Ostracoda in some marine food fishes in southeast region of Tamil Nadu India during June 2019 to May 2020 by the method of Becker’s measuring utility by a single-response sequential method. Total 540 fishermen belonging to 5 villages from Ramand District were interviewed to understand the public health issues related the infestation of Ostracoda V. tsujii in ten major marine food fishes i.e. Parupeneus indicus, Lutjanus fulviflamma, Priacanthus hamrur (Snapper), Carangoides gymnostethus, Carangoides malabaricus, Carangoides ferdau (Carangids), Cephalopholis sonnerati, Epinephelus coioides (grouper), Lethrinus ornatus and Plectorhinchus gibbosus (sea bream). Fishermen, local whole sale buyers, small fish-stall owners and fish consumers were part of respondents. It was observed that there was no difference at statistically significant level (P &lt; 0.05) between infested and healthy fish samples in terms of nutritional profile like protein, fat, ash, carbohydrates and mineral nutrients level. Based on the feedback and information obtained from respondents in the present study found that no incidence of health issues or risk associated with food fishes infested with Ostracoda Vargula tsujii (local name – Arattlai) or any other true parasites.

Stocks delineation of bull’s eye fish (Priacanthus hamrur) in Indian water using morphometric measurements and meristic counts

The Moontail bull’s eye (Priacanthus hamrur) is one of the commonly available fish species found in the deep sea and under ledges or hovering next to coral heads during the day. In the present study, around 300 specimens were collected from different location in east and west coast of India including Kakinada, Kolkata, Cochin and Mumbai to investigate the stock differentiation among the populations. A total of 14 morphometric traits and 10 meristic counts were studied. The descriptive statistics of morphometric traits indicated the much larger growth in populations of west coast compares to the east coast. The meristic traits were not much efficient in identifying the stocks. Pre pelvic fin length, post anal fin length, post dorsal length, pre dorsal fin length, head length, eye diameter, body depth, caudal peduncle depth and dorsal fin base helped in the separation of stocks. All the four stocks have separate morphometric features. The present study will provide the baseline information on the stock characteristics of P. hamrur from Indian water and management measures of the resources for sustainable utilization.

Stock structure analysis of Priacanthus hamrur (Forsskal, 1775) along the Indian coast based on truss morphometry

Marine biology,marine ecology,Phytoplankton, marine algae, zooplankton, nekton, benthos, corals and coral reefs, ecology, zoogeography and systematics, primary production and experimental work on ecosystem including energy flow at different trophic levels, population dynamics and theoretical models, recycling of matter, influence of environmental factors on metabolic activity, marine microbiology, mariculture and experimental work on propagation of cultivable species, biology of fishes, marine reptiles, sea birds and mammals, physical, chemical, geological and meteorological features of the environments related to marine biology, marine environmental damage caused by pollution and engineering works, underwater observations, conservation of living resources, modifications in methodology and techniques and development of new apparatus related to marine sciences

Fabrication and characterization of chitosan based collagen/ gelatin composite scaffolds from big eye snapper Priacanthus hamrur skin for antimicrobial and anti oxidant applications.

In this study, for developing a scaffold for tissue engineering from fish processing wastes, a hierachial collagen/gelatin/chitosan novel porous scaffold was fabricated using blends of collagen and gelatin extracted from the skins of Marine big eye snapper Priacanthus humrur. Scaffolds were developed by mechanical spinning of chitosan and by mixing of collagen and gelatin solutions followed by freeze drying and subsequent crosslinking of polymers. The scaffolds were evaluated for rheological properties - porosity, apparent density and swelling capacity to assess their mechanical property.Gelatin/chitosan composition shown very high porosity(81.02%) and incorporation of collagen shown higher density in Collagen/gelatin/chitosan scaffolds (0.0522g/cm3) and collagen/chitosan scaffolds (0.0468 g/cm3).Morphology of the prepared scaffolds were analyzed by Scanning Electron Microscopy which showed reduced pore size of 10 to 20μ in Collagen/gelatin/Chitosan composite, 5 to 10μ in gelatin/chitosan composites and 2-5μ in collagen/chitosan composites. FTIR analysis showed intense peaks ranging 1120 -11267 cm-1 in the three different scaffolds that are denoted as CH groups. In-vitro antioxidant investigation through DPPH assay showed that the composite 3 in 1 mg/ml concentration exhibited higher antioxidant potential (70%). In contrast, ABTS scavenging assay identified composite1 in 1 mg/ml had good antioxidant activity with highest percentage of inhibition (29.5%). The scaffolds were also evaluated for anti microbial properties through disc diffusion assay. The results showed maximum inhibition- 14 mm, 12 mm and 14 mm for 200 μg of the sample for collagen/chitosan, gelatin/chitosan and collagen/gelatin/chitosan scaffolds respectively towards E.Coli and 20 mm, 20 mm and 24 mm towards S.aureus. The zone of inhibition against E. coli and S. aureus for the three scaffolds was comparatively lower and that could be due to the presence of chitosan. The findings of the study indicates that the bioscaffolds are expected to have wide application in tissue engineering.

Confirmed occurrence of moontail bullseye, Priacanthus hamrur (Actinopterygii: Perciformes: Priacanthidae), in the Mediterranean Sea with first record off the coast of Turkey

A new Lessepsian migrant, moontail bullseye, Priacanthus hamrur (Forssk&aring;l, 1775), is recorded for the second time from the Mediterranean Sea, and for the first time from Turkey. A single male specimen of P. hamrur was caught at a depth of about 30 m, off the Konac&#305;k harbour (Arsuz coast, Gulf of Iskenderun, Turkey) on 18 December 2017, by a longline. The present paper reports the confirmed record of P. hamrur in the eastern Mediterranean with the first record off the coast of Turkey. This species is probably a Red Sea immigrant entering the Mediterranean Sea through the Suez Canal. With the present report, the number of priacanthid species reported in the Mediterranean Sea has reached four.

Fishery, biology and stock status of Priacanthus hamrur (Forsskal, 1775) exploited off Kerala coast

The present paper attempts to describe the fishery of priacanthids along Kerala coast during 2007-15, along with insights into certain aspects of the biology and stock status of the dominant species Priacanthus hamrur which formed more than 80% of the priacanthids landed during this period. The length-weight relationship estimated show that there is no significant difference in b values of male and female and the equation derived for sexes pooled W = 0.000047038 L2.76. Sex ratio revealed dominance of females over males (1:1.5). Spawning season of P. hamrur was from June to October with a peak in August. Growth parameters estimated were, L∞=404.25 mm, K=0.58 year-1 t0=-0.1370. Total mortality estimated was Z=3.70, natural mortality M=1.13 and fishing mortality F=2.57. The exploitation rate (E) of P. hamrur in Kerala coast was estimated at 0.69 which is above the optimum level.

Total lipid, phospholipid and cholesterol contents of seven marine fishes of Mumbai, Maharashtra

The total lipid, phospholipids and cholesterol contents in the muscles of seven marine fishes viz., Filimanus heptadactyla, Decapterus russelli, Amblygaster leiogaster, Coilia dussumieri, Priacanthus hamrur, Johnius sp. and Harpadon nehereus were analysed. Significant (p<0.05) variations in the lipid content was observed between the fishes with the highest value in A. leiogaster and lowest value in Johnius sp. and H. nehereus. Based on the total lipid contents fishes were classified as high fat fish (A. leiogaster), low fat fishes (F. heptadactyla and P. hamrur) and lean fishes (C. dussumerrie, D. russelli, H. nehereus and Johnius sp.). Overall, the study showed that the fishes were a good source of essential lipid with nutritional values

Species assemblages and community structure of deep-sea demersal ichthyofauna of the South-eastern Arabian Sea (SEAS)

Studies of species assemblages and community structure are of vital importance in the deep-sea realm. Data for the present study were collected during the research expedition of FORV ‘Sagar Sampada’ in the latitude 8.02°N and 11.58°N, longitude 74.16°E and 78.35°E. High Speed Demersal Trawl – Crustacean Version (HSDT-CV) was used for the operations at a depth of 200 and 1000 m. The total catch came to 2148.35 kg from 10 stations. An analysis of the catch composition was made. Total catch was dominated by Priacanthus hamrur (27.66%) followed by Neoepinnula orientalis (15.57%), Psenopsis cyanea (10.05%), Glyptophidium oceanium (3.55%), Lamprogrammus niger (3.17%), Narcine timlei (3.08%), Lamprogrammus sp. (2.6%), Pterigotrygla hemisticta (2.17%). About 76 species recorded from 22 orders were identified. The diversity indices, Cluster analysis, k-dominance plot were analysed using PRIMER v6 software. The diversity indices including Margalef richness index (d), Shanon index (log e2), Pielou's evenness index (J′) and Simpson diversity index (1 − λ) were calculated. Diversity indices were compared with the previous studies in the same area, and this can be a reference point for future studies.

Molecular identification of Bigeyes (Perciformes, Priacanthidae) from Indian waters

Thirty-five individuals of six priacanthid fish species were sampled from different localities along the coast of India covering the Arabian Sea and Bay of Bengal. The partial sequence of 16S rRNA and cytochrome oxidase subunit I (COI) genes were analyzed for species identification and phylogenetic relationship among the Indian priacanthids (Priacanthus hamrur, P. prolixus, P. blochii, P. sagittarius, Cookeolus japonicus, and Pristigenys refulgens). The intraspecies genetic distance ranged from 0.000 to 0.002, while distances varied from 0.008 to 0.157 interspecies based on 16S sequences. Using COI data analysis, the intraspecies genetic distance ranged from 0.000 to 0.005, while interspecies distances varied from 0.009 to 0.108. Several sequences labeled Priacanthus hamrur in GenBank are shown to be P. prolixus. We also observed cryptic speciation in Heteropriacanthus cruentatus. Partial sequences of 16S rRNA and COI genes provided phylogenetic information to distinguish thirteen species of priacanthids, indicating the usefulness of molecular markers in species identification.

Molecular characterization and new geographical record of Lecithochirium priacanthi (Digenea: Hemiuridae) infecting the moontail bullseye fish Priacanthus hamrur (Perciformes: Priacanthidae) from the Red Sea, Egypt.

Sixty specimens of the moontail bullseye Priacanthus hamrur were collected at Coasts of Suez Gulf, Red Sea (Egypt) during the four different seasons of the whole year 2014 and necropsied to study the infection with metazoan parasites. Twenty-one out of 60 examined fish specimens (infection rate of 33.33%) were found to be naturally infected by the hemiurid digenean parasite Lecithochirium priacanthi. The large-sized fish reaching 15-30 (23.5 ± 4.8) cm were more intensively infected than the smaller ones. A definite seasonal effect was observed as winter was found to be the season of severe parasitic infections, while midsummer was the lowest one. The morphological and morphometric characterization of this parasite were examined by light and scanning electron microscopy. The adult worms had an elongated body measuring 1.93-2.54 (2.11 ± 0.20) mm in length and 0.61-0.72 (0.67 ± 0.02) mm in width. The body was characterized by the presence of a sub-terminal oral sucker with diameters reaching 0.12-0.16 (0.14 ± 0.02) mm. The ventral sucker measured 0.32-0.45 (0.38 ± 0.02) mm in diameter. The body was supplied by a short retracted portion with a blunt end that measured 0.48-0.61 (0.56 ± 0.02) mm in length and 0.28-0.35 (0.32 ± 0.02) mm in width. Morphological results of the present parasite were compared with other related species described previously from Perciformes. Molecular characterization based on small subunit ribosomal DNA was done to confirm the obtained morphological and morphometric results. A preliminary genetic comparison between SSU rDNA of this parasite and other species of Hemiuridae places the present specimen as a putative sister taxon to Lecithochirium grandiporum and Lecithochirium caesionis. The finding of L. priacanthi in Egyptian marine water fish represents a new geographical record for this parasite.

Biochemical Changes in Dressed Priacanthus hamrur (Bull’s Eye) During Frozen Storage and Its Effect on Physical and Sensory Quality of Fish Sausage

In the present investigation, biochemical changes in dressed and frozen stored Priacanthus hamrur and their influence on quality of fish sausage have been studied. During the frozen storage period of five months, moisture content decreased and led to the increment on other proximate constituents due to percentage balance. Quality indices such as total volatile base nitrogen and trimethyl amine nitrogen increased significantly (P < 0.05) and reached 44.80 mg N/100 g and 22.00 mg N/100 g of meat, respectively. Non-protein nitrogenous contents were found to decrease due to the loss in thaw drip. Lipid freshness parameters such as peroxide value and free fatty acid value increased and resulted in reduced extractability of salt soluble proteins. Gel strength of fish sausage decreased significantly (P < 0.05) during the storage period and this was also supported by the folding test. Increments in the expressible moisture content clearly indicated the loss of protein functionality, like water holding ability, due to denaturation during frozen storage. From the sensory evaluation, dressed P. hamrur can be stored frozen without any cryoprotective and preservative agents up to four months when it is intended for the preparation of fish sausage and this was also evidence from the changes in biochemical constituents.

Feeding habits and food partitioning between three commercial fish associated with artificial reefs in a tropical coastal environment

At Réunion Island (south-western Indian Ocean), artificial reefs were submerged in 2003 in a bay and were soon colonised by fish, among which were the highly abundant commercial species Lutjanus kasmira, Priacanthus hamrur and Selar crumenophthalmus. The high concentration and diversity of fish around the artificial reefs is surprising, considering the low abundance of potential benthic prey. We investigated the diet and food partitioning between the aforementioned species using stomach content and stable isotope analyses (δ13C, δ15N). Priacanthus hamrur and S. crumenophthalmus fed on a larger prey diversity and showed significant overlap in their diets, with crustacean larvae the dominant prey. Fish larvae dominated L. kasmira's diet, and δ15N values confirmed the species’ higher trophic level. Differences in δ13C between P. hamrur and S. crumenophthalmus indicated niche segregation, probably as a way to reduce competition, with P. hamrur being characterised by a smaller δ13C range and exhibiting a smaller isotopic niche than S. crumenophthalmus. There was a significant correlation between δ15N and fish standard length for the three species, suggesting that ontogeny partially explained the niche breadth. There was also a significant correlation between δ13C and length for L. kasmira, whereas individual specialisation was prevalent in S. crumenophthalmus.

COMPOSITION, PHYSICOCHEMICAL AND RHEOLOGICAL PROPERTIES OF FRESH BIGEYE SNAPPER FISH (PRIACANTHUS HAMRUR) MINCE

ABSTRACT Composition and properties of fresh bigeye snapper fish (Priacanthus hamrur) mince has been investigated. The protein content of fish mince was 16.71 g/100 g mince. Amino acid analysis revealed high proportion of glutamic acid, alanine, lysine and leucine. Fatty acid profile indicated high proportion of eicosa pentaenoic acid and decosa hexaenoic acid content. Gel filtration profile of total proteins from fresh bigeye fish mince revealed a major peak (high molecular weight component) and a few minor peaks, which was further confirmed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis pattern. The differential scanning calorimetry profile of fresh bigeye fish mince revealed transitions at 38.35, 47.72 and 63.02C indicating denaturation temperature of different protein fractions. The gel-forming ability of fresh bigeye fish mince was evaluated by both small strain and large strain tests. The flow behavior of total protein solution from fresh bigeye fish mince as a function of protein concentration and temperature showed pseudoplastic behavior. PRACTICAL APPLICATIONS The properties of fish mince including amino acid and fatty acid profile are critical in deciding the nature of processed products to be prepared. Because of lower catch of bigeye snapper in formerly, this fish was not commonly available and hence, it has been regarded as a nonconventional marine fishery resource. Recently, bigeye snapper has assumed significance as an important species in the commercial landings. In the present investigation, composition, thermal and rheological properties of fresh bigeye snapper mince have been assessed. A high proportion of omega 3 fatty acids shows the nutritional importance of this fish whereas its gel-forming ability shows the potential to be utilized as raw material in the surimi industry. Establishing the thermal denaturation profile, measurement of dynamic viscoelstic behavior and assessing the flow behavior of proteins from bigeye snapper will aid in the appropriate processing and design in formulating mince-based products.

Isolation of human pathogenic bacteria in two edible fishes, Priacanthus hamrur and Megalaspis cordyla at Royapuram waters of Chennai, India

Two edible fishes, Bulls eye, Priacanthus hamrur (Percidae) and Hard tail scad, Megalaspis cordyla (Carangidae) from the waters of Royapuram coast, Chennai, Tamil Nadu were chosen for isolation of bacterial human pathogens in their gills, intestine, muscle and skin. Based on their growth characteristics on specific culture media, the following human bacterial pathogens, Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa, Vibrio cholerae and Shigella dysenteriae were isolated in both the fishes. The medium of the fishes and the sediments of their habitat were furthermore collected and examined for pathogens. Different bacterial species were found in the medium that was analyzed, including the human pathogens isolated from the fishes. Surprisingly the five human bacterial pathogens harbored in the fishes were found in the medium but not in the sediment. This research is primarily to highlight the quality of these two edible fishes in the coastal waters of Royapuram, Chennai and to create awareness amid fish eating population. Keywords: Fish, water pollution, E. coli, Salmonella typhi, Pseudomonas aeruginosa, Vibrio cholerae, Shigella dysenteriae, Priacanthus hamrur, Megalaspis cordyla

Isolation of human pathogenic bacteria in two edible fishes, Priacanthus hamrur and Megalaspis cordyla at Royapuram waters of Chennai, India

Two edible fishes, Bulls eye, Priacanthus hamrur (Percidae) and Hard tail scad, Megalaspis cordyla (Carangidae) from the waters of Royapuram coast, Chennai, Tamil Nadu were chosen for isolation of bacterial human pathogens in their gills, intestine, muscle and skin. Based on their growth characteristics on specific culture media, the following human bacterial pathogens, Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa, Vibrio cholerae and Shigella dysenteriae were isolated in both the fishes. The medium of the fishes and the sediments of their habitat were furthermore collected and examined for pathogens. Different bacterial species were found in the medium that was analyzed, including the human pathogens isolated from the fishes. Surprisingly the five human bacterial pathogens harbored in the fishes were found in the medium but not in the sediment. This research is primarily to highlight the quality of these two edible fishes in the coastal waters of Royapuram, Chennai and to create awareness amid fish eating population.

Trophic organisation and predator–prey interactions among commercially exploited demersal finfishes in the coastal waters of the southeastern Arabian Sea

Trophic interactions in commercially exploited demersal finfishes in the southeastern Arabian Sea of India were studied to understand trophic organization with emphasis on ontogenic diet shifts within the marine food web. In total, the contents of 4716 stomachs were examined from which 78 prey items were identified. Crustaceans and fishes were the major prey groups to most of the fishes. Based on cluster analysis of predator feeding similarities and ontogenic diet shift within each predator, four major trophic guilds and many sub-guilds were identified. The first guild ‘detritus feeders’ included all size groups of Cynoglossus macrostomus, Pampus argenteus, Leiognathus bindus and Priacanthus hamrur. Guild two, named ‘Shrimp feeders’, was the largest guild identified and included all size groups of Rhynchobatus djiddensis and Nemipterus mesoprion, medium and large Nemipterus japonicus, P. hamrur and Grammoplites suppositus, small and medium Otolithes cuvieri and small Lactarius lactarius. Guild three, named ‘crab and squilla feeders’, consisted of few predators. The fourth trophic guild, ‘piscivores’, was mainly made up of larger size groups of all predators and all size groups of Pseudorhombus arsius and Carcharhinus limbatus. The mean diet breadth and mean trophic level showed strong correlation with ontogenic diet shift. The mean trophic level varied from 2.2 ± 0.1 in large L. bindus to 4.6 ± 0.2 in large Epinephelus diacanthus and the diet breadth from 1.4 ± 0.3 in medium P. argenteus to 8.3 ± 0.2 in medium N. japonicus. Overall, the present study showed that predators in the ecosystem have a strong feeding preference for the sergestid shrimp Acetes indicus, penaeid shrimps, epibenthic crabs and detritus.