Snapper Fish Research Articles

The application of material handling in fish fillet production process of red snapper in PT X

Fish is one type of food that contains protein, fat, vitamins and minerals that are good in fulfilling necessary for human nutrition. Indonesia is a country with fisheries anda marine resources reaching 5.8 million km with a potential of 6.4 million tons of fish every year. PT X is one of the companies engaged in fish freezing in Indonesia which has exported many products to several countries. Production activities are the most dominant part carried out by PT X. A good production management system is system that regulates the smooth process of its production, besides that it is also determined by the proper handling of materials. In any companies, include PT. X, production activities are critical, thus a good production management is necessary to smoothing the production process and material handling. While, the material handling itself has a big portion in the operational cost. The purpose of this study was aimed to determine the application of material handling and the costs required in the process of handling red snapper fish in PT X. The results of the application of material handling that there are 8 directions of material transfer in the process of fish fillet production in PT X namely the transfer of material to Carbon monoxide’s (CO) room, transfer to Air Blast Freezer (ABF), transfer to packing room, transfer to cold storage and transfer from ABF to containers. From these transfer, the total cost of these material transfer per day in PT X is IDR 291,592.94.

New records of two Lutjanus species (Teleostei: Perciformes: Lutjanidae) with re-description of six lutjanids from Saint Martin’s Island of the Bay of Bengal, Bangladesh

Investigations on Snapper fish of the genus Lutjanus were conducted from October 2015 to April 2016 in the coral ecosystem of St. Martin’s Island, Bangladesh. Twenty one individuals of 8 species of Lutjanus were collected from local fishermen. Both morphological characters and DNA barcoding approach by mitochondrial cytochrome oxidase I subunit (COI) were used to confirm the identification of all species. Present study recorded the first national occurrence of two reef associated Lutjanus species (L. xanthopinnis and L. indicus). In addition six species (L. rivulatus, L. lutjanus, L. vitta, L. lemniscatus, L. fulviflamma and L. johnii) were re-described. Distinct morphological differentiation were found between more closely related species L. xanthopinnis, L. vitta and L. lutjanus. Three different appearances of L. johnii, two different appearances of L. rivulatus and L. lemniscatus were confirmed as same species. Phylogenetic analysis showed monophylotic clade for conspecific individuals and paraphyletic clade for congeneric individuals. Average genetic divergence for intraspecific level was 1.5% and 12.5% for interspecific level. Current study increased the number of Lutjanus species in Bangladesh from 15 to 17 and extended the distribution range of those new recorded species in northeastern part of the Bay of Bengal.
 Bangladesh J. Zool. 46(2): 239-253, 2018

Bioceramics synthesis of hydroxyapatite from red snapper fish scales biowaste using wet chemical precipitation route

Fish scales biowaste contain high collagens and calcium phosphates, therefore have considerable potential as raw material for value-added biomaterial such as hydroxyapatite (HAp). HAp is the main constituent component of hard tissue such as bone and teeth in the human body and is known as bioceramic materials. In this work, wet chemical precipitation method was used to syntesize HAp from Red Snapper Fish (Lutjanus campechanus) Scales. Two variations of calcination temperatures of 600°C (FHAp1) and 800°C (FHAp2) were conducted for 5 hours. The results showed calcium content from biowaste of red snapper fish scale was 83.62%. FTIR result shows that PO43-, OH-, and CO32- functional groups presence as indicates the formation of HAp. XRD result showed the degree of crystallinity for FHAp1 and FHAp2 were 75.52% and 79.20%, respectively. The degree of crystallinity is in accordance with ISO 13779-2:2000 standard in which the minimum degree of crystallinity of hydroxyapatite used for biomedical materials is 45%. Finally, Particle Size Analyzer (PSA) results show that the particle size distribution is evenly distributed, with the size of micro-scale hydroxyapatite particles, ranging from 5.76 μm to 132.64 μm.

Characterization of chitin extracted from fish scales of marine fish species purchased from local markets in North Sulawesi, Indonesia

Chitin is a biodegradable biopolymer with a variety of commercial applications, including in the food food-supplement industries as a marine-derived nutraceutical. The purpose of this study was to characterize the molecular structure of chitin extracted from fish scales of important marine fish purchased from local markets in North Sulawesi. Chitin compound material was obtained from a specific fish scale, and then sequentially carrying out a boiling treatment to separate it from a complex with collagen. From the scales of two fish species, parrotfish (Chlorurus sordidus) and red snapper (Lutjanus argentimaculatus), the rendemen of chitin obtained were 45 % and 33%, respectively. Structural characteristics of the chitin were discussed by FTIR (Fourier Transform Infrared) analysis data. FTIR analysis was done using infrared spectroscopy, which is the resulting spectrum represents the molecular absorption and transmission, creating a molecular fingerprint of the sample. The molecular structure of chitin, C18H26N2O10, where the hydroxyl group on the second carbon replaced by acetyl amide, was shown by the infrared spectra. In the infrared spectra, chitin from parrot fish scales indicated the amide band at 1627.13 cm−1, and chitin from red snapper fish scales the amide band at 1648.09 cm−1 which are a typical one for marine chitin. The hydroxyl and amino bands at the ranged spectra up to 3500 cm−1. The yields of chitin isolated from fish scale were relatively huge. Some treatments are necessary to confirm the molecular conformation and deacetylation behavior. All products from the extraction of fish scales could be more accessible for structural modifications to develop biocompatible materials for pharmaceutical purposes.

Molecular Characterization of Mosquitocidal Toxin (Surface Layer Protein, SLP) from Bacillus cereus VCRC B540.

A marine Bacillus cereus (VCRC B540) with mosquitocidal effect was recently reported from red snapper fish (Lutjanus sanguineous) gut and surface layer protein (S-layer protein, SLP) was reported to be mosquito larvicidal factor. In this present study, the gene encoding the surface layer protein was amplified from the genomic DNA and functionally characterized. Amplification of SLP-encoding gene revealed 1,518bp PCR product, and analysis of the sequence revealed the presence of 1482bp open reading frame with coding capacity for a polypeptide of 493 amino acids. Phylogenetic analysis revealed with homology among closely related Bacillus cereus groups of organisms as well as Bacillus strains. Removal of nucleotides encoding signaling peptide revealed the functional cloning fragment of length 1398bp. Theoretical molecular weight (51.7kDa) and isoelectric point (5.99) of the deduced functional SLP protein were predicted using ProtParam. The amplified PCR product was cloned into a plasmid vector (pGEM-T), and the open reading frame free off signaling peptide was subsequently cloned inpET-28a(+) and expressed in Escherichia coli BL21 (DE3). The isopropyl-β-D-thiogalactopyranoside (IPTG)-induced recombinant SLP was confirmed using western blotting, and functional SLP revealed mosquito larvicidal property. Therefore, the major findings revealed that SLP is a factor responsible for mosquitocidal activity, and the molecular characterization of this toxin was extensively studied.

Synthesis and Characterization of Composite Poly(1.8 Octanediol-co-Citrate) (POC)/Nano-Hydroxyapatite as Candidate Biodegradable Bone Screw

The high number of bone fractures, around 300-400 cases per month, are treated with orthopedic surgery method using internal fixation by bone screw which is aimed at accelerating patients’ mobilization. There is a necessity to invent biomaterial which possesses two main characteristics: biocompatible and biofunctional, as well as having an important element of biodegradable without conducting reoperation. A research focused on the various composition of nano-hydroxyapatite (HA) derived from extracted snapper fish scales on Poly (1,8-octanediol-Co-Citrate (POC) as Biodegradable Bone screw. This research is purported to synthesize Poly (1,8-Octanediol-co-Citrate (POC) and characterize the influence of HA compositions against mechanical properties and compatibility of POC-HA composite that enable it to be used as Biodegradable Bone screw material. The condensation polymerization method is applied in synthesizing POC to produce POC pre-polymer by the formation of an ester bond group C=O stretch at 1731 cm-1 through a test of functional groups (FTIR). POC pre-polymer is composited with nano-HA compositions of 62%, 65%, 68% and 71% and followed by post-polymerization treatment. POC-HA composites formed were tested on hardness and biodegradability. The results obtained indicate that the composition of HA nanoparticles influences the mechanical properties and biocompatibility of the material. Best results were from 62% HA composition in which the hardness value was of 885.57 MPa, close to that of bone hardness which is 150-664 MPa. Results also showed that the rate of biodegradation reached 3.42% (4 weeks) which is in accordance to fracture bone grafting period of 21 months. Based on the characteristics result indicated in this study, the composite of Poly (1,8-Octanediol-co-Citrate) (POC)-Nano Hydroxyapatite is a potential candidate for biodegradable bone screw material.

PREFERENSI KONSUMEN TERHADAP PRODUK HASIL LAUT (STUDI KASUS RESTORAN SEAFOOD MJM KOTA PALU, SULAWESI TENGAH)

Many bussinessman develop the restaurant of seafood in the Palu Town, Central Sulawesi. The production’s fisheries activities yielded high protein products and consumed by community, not only limited to fisheries products but also the processed product with various taste. One of the products of fisheries that distributed in the market were the marine products in The Palu town. The objectives of this study is to analyse the preferences of consumer on the marine products in the Palu town. The study method is the case study (case study with a unit of famous seafood restaurant cases MJM that located in the Palu town. The sampling method which used in this study was accidental sampling. The type of fisheries product that sold in the Seafood Restaurant of MJM were groupers, snapper fish, baronang, katamba, mangrove’s crabs, shrimps and squid. The interest of marine product was undertaken with analysis of multiple linear regression and yielded F-count > F-Table with level of significance 95% shown concordance of consumer’s interest to attribute of product. Simultanously, attribute of product of diversity (X1) = , quality (X2), price (X3), taste (X4), and service (X5) have influenced significantly to preference of consumer whereas partially, the product attribute of quality (X2) possess effect the most dominant with coefficient of regression value is 0,531 or 53,1%. Thus, the preference of consumer to marine product is quality of fish was level of freshing quality, clean, consumed healthty.

First occurrence of Argathona macronema (Bleeker, 1857) (Isopoda: Cirolanidae) on coral reef fishes along the Tuticorin coastal water, Gulf of Mannar.

Isopod Parasites are considered as a major threat to the fishing industry, due to rigorous disease outbreaks. The parasites from the two economically important reef fish family Lutjanidae and Serranidae are analyzed i.e. Epinephelus malabaricus and Lutjanus rivulatus. The samples are obtained from the landings of Trawl net from Gulf of Mannar region of South east coast of India. They are severely infested by the isopod parasite Agrathona macronema in the Pectoral fins and ventral region of the body. This species is found to be the new record in the Gulf of Mannar region and deposited in the Marine laboratory of Kamaraj College. Length and weight of the host and parasites are measured. The parasites infested on 13 specimens of E. malabricus out of 8 and 17 out of 12 species of L. rivulatus. The prevalence of parasite on the grouper and snapper fish (61.53 and 70.58%) and mean intensity (2.62 and 2.58%) respectively. The prevalence was maximum in L. rivulatus and minimum in E. malbaricus may be to the host specificity. Further studies are needed to know the life cycle of the parasite, host preference, disease outbreak and its role in the coral reef ecosystem.

MONITOREO DE LOS NIVELES DE TESTOSTERONA Y ESTRADIOL EN EL PLASMA SANGUÍNEO DE HEMBRAS DE PARGO PALMERO LUTJANUS ANALIS MANTENIDAS BAJO DOS TERMOPERIODOS DE ACONDICIONAMIENTO DIFERENTES

Two groups of adult Mutton snapper fish Lutjanus analis captured in the wild, each one of three females and four males, were kept during eight months under controlled temperature and photoperiod conditions in the lab in order to stimulate their sexual maturation which was in a state of latency because of the effects of confinement. The first group was maintained under an artificial cycle with temperature manipulation and the second under a control cycle, in which this parameter was left at natural conditions. Every two months blood samples from all females were taken for the analysis of plasma testosterone (T) and oestradiol (E2) levels, taking ovarian biopsies simultaneously to register the mean diameter of the oocytes. After six months, a significative increase in the mean diameter of the oocytes of the three females of the artificial cycle was observed, with coincidence and statistic relationship with the increase in the T and E2 (r = 0.62 y 0.82 respectively). No oocyte growth was observed in the females under the control cycle. In both, artificial and control cycles, T and E2 levels showed a close relationship with photoperiod (r = 0.84 y r = 0.61) while temperature showed a lower or non significant relationship (r = 0.40 y r = 0.20). Statistical differences (P<0.1) were found between the condition factors of the two groups, while the sexual steroids didn’t show any differences between them. The present work constitutes the first report on the analysis of sexual steroid levels during the gonadal maturation process in fish of the Family Lutjanidae kept under an artificial conditioning cycle.

Effects of exogenous non-starch polysaccharide-degrading enzymes in diets containing Gracilaria lemaneiformis on white-spotted snapper Lutjanus stellatus Akazaki

A feeding experiment was conducted to investigate the effects of exogenous non-starch polysaccharide (NSP)-degrading enzymes in diets containing Gracilaria lemaneiformis (GL) on growth performance and digestive enzyme activities of white-spotted snapper Lutjanus stellatus Akazaki (initial mass 8.0 ± 0.1 g). A basal diet (D0) containing a mixed protein source (fish meal, soybean meal and GL meal) was used as the control. Two diets supplemented with 0.5 g (D1) and 1 g (D2) exogenous NSP-degrading enzymes per kilogram of diet were formulated. Each diet was assigned to triplicate groups of fish in a total of nine floating sea cages (270 fish, 30 fish per cage). After a 60-day feeding trail, significantly higher weight gain, specific growth ratio and feed efficiency ratio were observed in fish fed D2 diet compared to those of control (P < 0.05). Body lipid, moisture and ash contents were not significantly affected by NSP-degrading enzyme supplementation, but significantly higher protein content was noticed in fish fed D2 diet compared to that of control (P < 0.05). The amylase activity in the stomach and intestine was significantly higher in fish fed D2 diet (P < 0.05), but no significant differences were observed in pepsin and lipase activities in the stomach or trypsin and lipase activities in the intestine between all treatments. The results suggested that addition of 1 g kg−1 NSP-degrading enzymes in diet could efficiently improve seaweed feed utilization and growth performance of white-spotted snapper fish.

Comparison of mercury bioaccumulation between wild and mariculture food chains from a subtropical bay of Southern China.

Bioaccumulation and trophic transfer of mercury (Hg) both in the natural marine ecosystem and the mariculture ecosystem were studied at Daya Bay, a subtropical bay in Southern China. Averaged Hg concentrations in sediment, phytoplankton, macrophyte, shrimp, crab, shellfish, planktivorous fish, carnivorous fish, farmed pompano, farmed snapper, compound feed and trash fish were 0.074, 0.054, 0.044, 0.098, 0.116, 0.171, 0.088, 0.121, 0.210, 0.125, 0.038 and 0.106μgg(-1)dw, respectively. These Hg levels were at the low-middle ends of the global range. Positive correlation between Hg concentrations in farmed fish and fish weights/sizes was observed, whereas no clear correlation between Hg concentrations and lipid contents was found. Hg concentrations followed macrophyte<phytoplankton<sediment<planktivorous fish<shrimp<crab<carnivorous fish<shellfish, and commercial feed<trash fish<farmed fish. Hg was biomagnified along the marine food chain in the ecosystem of Daya Bay. Hg levels in the farmed fish were higher than those in the wild fish primarily because of the higher Hg level in fish feed and the smaller size of marine wild fish.

Anatomical and surface morphology of Hedruris lutjanenses sp. n. (Nematoda: Hedruridae) from the common marinewater fish Lutjanus synagris in Damietta, Egypt.

The description and tegumental ultrastructure of nematode Hedruris lutjanenses sp. n. collected from marine Lane Snapper fish Lutjanus synagris Linnaeus, 1758 collected at Manzala Lake, Damietta, Egypt was studied by light and Scanning Electron Microscopy (SEM). The new species is mainly characterized by that the buccal capsule is surrounded by four pseudolapia; one small and three larger pseudolapia, each one bears a number of papillae arranged irregularly on its surface and the presence of one pair of precloacal papillae and nine pairs of postcloacal ones in males.

Identification and characterization of a novel marine Bacillus cereus VCRC-B540 for mosquito control

A marine bacterium with mosquitocidal effect was isolated from the gut region of the marine red snapper fish (Lutjanus sanguineous). The 16S rRNA gene sequence alignment showed that this isolate belonged to the strain Bacillus cereus VCRC-B540 (NCBI: JN377787). Biochemical studies showed that the strain could be useful in mosquito control. It showed an increasing pattern of toxicity for Culex quinquefasciatus, Anopheles stephensi, and Aedes aegypti, without negative effects for the non-targeted organisms Chironomus riparius, Daphnia cephalata and Notonecta glauca. A qualitative analysis of B. cereus showed that a polypeptide (M.wt: 90 kDa) was associated with the toxicity observed. Consequently, the peptide sequence is identified to be a surface layer protein. A phylogenetic analysis of 16S rDNA gene sequence of B. cereus revealed shared homology with the Bacillus species. Hence, it is concluded that the marine bacterium (B. cereus) can be useful in the biological control of mosquito vectors.

POTENSI DAN TINGKAT PEMANFAATAN SUMBERDAYA IKAN DEMERSAL DI PERAIRAN PULAU AMBON PROVINSI MALUKU

One of the fishery resources that have high economic value are demersal fisheries resources in deep sea waters. The results ofthis study found 22 demersal fish species with high economic value captured by fishermen. The results ofthe study found as many as 22 species, five fish stretcher 5 that can be foundin nearly all areas and fishing season. Five types of fish are: lencam (Lethrinus sp.), kurisi (Etelis spp), kerapu (Ephinephelus sp), red snapper (Lutjanus spp), bubara fish (Caranx sp). The types of fish catches were found spread around the waters of Ambon Island. The potential at Maxsimum sustainable Yield (MSY) of fish grouper (Epinephelus spp) 572.02 with 15.75 tonnes optimum effort trip. The average production of 178.919 tonnes currently. Thus the average utilization rate of groupers currently 31.27% or 68.72% untapped. If it is based on the MSY allowable catch for the fish species is 457.60 tons / year. MSY red snapper (Lutjanus spp) 146.83 wih 2.631 tonnes optimum effort trip. Average production is currently 67.704 tons. Thus the average utilization rate of the red snapper fish is currently 47.47%, or in other words the potential for red snapper untapped 52.52%. If it is based on the MSY allowable catch for the fish species is 117 464 tons / year. MSY bubara fish (Caranx sp) 270.60 tonnes with optimum effort 3630 trip with an average yield of 72.96 tons.

Red Snapper Fish Resources (Etelinae Subfamily) in Pasi of Lease Islands Maluku Province

Red snapper (Etelinae subfamily) is demersal fishery resources. It becomes export commodity because of having economic value, fish food quality and delicious taste. Besides, red snapper becomes recreational fishing object in various tropic and subtropical countries. For years, people on Lease Islands, Central Maluku have been hereditary catching red snapper in specific sites called "pasi". Caught red snapper types in pasi by Lease's people are called as "bae" fish. This study aims to: 1) identify caught red snapper types in pasi of Lease Islands. 2) determine the distribution, density and red snapper potential in pasi. Data sampling is conducted through acoustic survey, interview and observation. Density of fish is gained by BioSonics, 2004; 2010. Identification result shows that deep sea red snapper (Etelinae subfamily) called as "bae fish" on Lease Islands consists of 4 types, they are: Etelis radiosus, E. coruscans, E carbunculus and Aphareus rutilans. These fish types inhabit waters at about 90-140 m deep, while its total length (TL) are ranging from 30-85 cm. Total density of fish school is 0.0477 individual/m2, the maximum sustainable yield (MSY) is 400.33 individual/year and total allowable catch (TAC) is 320,267 individual/year.

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.

Stable isotope analysis reveals ontogenetic migration and the importance of a large mangrove estuary as a feeding ground for juvenile John’s snapper Lutjanus johnii

Stable carbon (δ13C) and nitrogen (δ15N) isotope ratios were measured to investigate the migration of John’s snapper Lutjanus johnii and its dependence on the food resources provided within the large Matang Mangrove Forest Reserve (40,151 ha), Malaysia. John’s snapper, and its main prey food such as penaeids, Acetes shrimps and mysids, showed generally depleted δ13C values in the inner mangrove area but more enriched values in the river mouth and coastal area. Some juveniles migrated into the inner mangrove areas, although they were also distributed near the river mouth areas. Isotopic signatures of snapper fish and prey reveal the ontogenetic migration of the youngest juvenile fish (<5 cm in total length) from the coastal area into the mangrove area, shifting their dependence from the coastal food web to the inner mangrove food web with their growth. The study shows the importance of the complex interconnected mangrove waterways and associated prey animals present in the large mangrove system to juvenile John’s snapper.

Psychrobacter sanguinis sp. nov., recovered from four clinical specimens over a 4-year period

An analysis of 16S rRNA gene sequences from archived clinical reference specimens identified a novel species of the genus Psychrobacter, of which four strains have been independently isolated from human blood. On the basis of 16S rRNA gene sequence similarity, the closest relatives with validly published names were Psychrobacter arenosus R7(T) (98.7%), P. pulmonis CECT 5989(T) (97.7%), P. faecalis Iso-46(T) (97.6%) and P. lutiphocae IMMIB L-1110(T) (97.2%). Maximum-likelihood phylogenetic analysis of 16S rRNA gene sequences showed that the isolates belonged to the genus Psychrobacter and were members of a cluster associated with Psychrobacter sp. PRwf-1, isolated from a silk snapper fish. DNA-DNA relatedness and partial 23S rRNA gene sequences also supported the finding that the isolates belonged to a species distinct from its closest phylogenetic neighbours. The predominant cellular fatty acids were C(18:1)ω9c, C(16:0), summed feature 3 (C(16:1)ω7c and/or iso-C(15:0) 2-OH), summed feature 5 (C(18:2)ω6,9c and/or anteiso-C(18:0)) and C(18:0). Biochemical and morphological analysis further supported the assignment of the four isolates to a novel species. The name Psychrobacter sanguinis sp. nov. is proposed. The type strain is 13983(T) (=DSM 23635(T)=CCUG 59771(T)).

Ovarian abnormality in a pathological case caused by Myxidium sp. (Myxozoa, Myxosporea) in onespot snapper fish Lutjanus monostigma (Teleostei, Lutjanidae) from the Red Sea

AbstractTo date, Myxidium elmatboulii Ali, Abdel-Baki et Sakran, 2006 (Myxozoa, Myxosporea) is the only species of the genus known from the Red Sea, and was originally described as a coelozoic parasite in the gall bladder of the belonid fish, Tylosurus choram. A Myxidium sp. closely similar to M. elmatboulii is described herein for the first time as a histozoic parasite in the ovary of the onespot snapper fish, Lutjanus monostigma (Teleostei, Lutjanidae) from the Red Sea coast of Saudi Arabia. The infected ovary was morphologically abnormal, with two protruding digitiform black cysts at its distal end, densely packed with mature plasmodia suspended in a mucoid liquid. Histological examination revealed that the cysts were extended deeply within the ovary, and each was surrounded by a capsule consisting of a relatively thick layer of fibrous connective tissues of host origin (host tissue reaction), and followed internally by a distinct black layer composed of melanomacrophages encircling the parasite mass; this layer clearly indicates the ability of this myxosporean parasite to induce a strong immune inflammatory response in the ovary of L. monostigma. Many small or developing cysts with the same characteristics were seen scattered in the connective tissue between the ovarian follicles. Plasmodia or spores of the parasite were not seen within the oocytes or within its developmental stages. The cysts occupied a considerable part of the ovary, and some areas of the ovarian tissues appeared to be vacuolated or degenerated. Thus, the typical ovarian structure of L. monostigma was greatly affected and lost its normal architecture. Therefore, the infection caused by this Myxidium sp. is presumed to negatively affect the reproductive capacity of the fish host.

Activity of natural radionuclides and their contribution to the absorbed dose in the fish cubera snapper (lutjanus cyanopterus, cuvier, 1828) on the coast of Ceara, Brazil

A methodology was developed for converting the activity concentration of radionuclides (Bq kg-1) into absorbed dose rate (Gy y-1), aiming an approach to environmental radioprotection based on the concept of standard dose limit. The model considers only the internal absorbed dose rate. This methodology was applied to the cubera snapper fish (Lutjanus cyanopterus, Cuvier, 1828) caught off the coast of Ceará. The natural radionuclides considered were uranium-238, radium-226, lead-210, thorium-232 and radium-228. The absorbed dose rates were calculated for individual radionuclides and the type of emitted radiation. The average dose rate due to these radionuclides was 5.36 µGy y-1, a value six orders of magnitude smaller than the threshold value of absorbed dose rate used in this study (3.65 10³ mGy y-1), and similar to that found in the literature for benthic fish. Ra-226 and U-238 contributed 67% and 22% of the absorbed dose rate, followed by Th-232 with 10%. Ra-228 and Pb-210, in turn, accounted for less than 1% of the absorbed dose rate. This distribution is somewhat different from that reported in the literature, where the Ra-226 accounts for 86% of the absorbed dose rate.