Obtainment and characterization of digestive aspartic proteases from the fish Caranx hippos (Linnaeus, 1766)

This work aimed to obtain aspartic proteases of industrial and biotechnological interest from the stomach of the crevalle jack fish (Caranx hippos). In order to do so, a crude extract (CE) of the stomach was obtained and subjected to a partial purification by salting-out, which resulted in the enzyme extract (EE) obtainment. EE proteases were characterized physicochemically and by means of zymogram. In addition, the effect of chemical agents on their activity was also assessed. By means of salting-out it was possible to obtain a purification of 1.6 times with a yield of 49.4%. Two acid proteases present in the EE were observed in zymogram. The optimum temperature and thermal stability for EE acidic proteases were 55 ºC and 45 °C, respectively. The optimum pH and pH stability found for these enzymes were pH 1.5 and 7.0, respectively. Total inhibition of EE acid proteolytic activity was observed in the presence of pepstatin A. dithiothreitol (DTT) and Ca2+ did not promote a significant effect on enzyme activity. In the presence of heavy metals, such as Al3+, Cd2+ and Hg2+, EE acidic proteases showed more than 70% of their enzymatic activity. The results show that it is possible to obtain, from the stomach of C. hippos, aspartic proteases with high proteolytic activity and characteristics that demonstrate potential for industrial and biotechnological applications.

Presence and concentration of polycyclic aromatic hydrocarbons (PAHs) in sediments and organisms from Tampamachoco coastal lagoon and Tuxpan River, Veracruz; México.

Polycyclic aromatic hydrocarbons (PAHs) have carcinogenic and mutagenic properties and their main origin in the environment is the burning of fossil fuels and organic material and they are considered high priority Persistent Organic Compounds (POPs). In the present study (March and August 2018) the concentrations of the 16 priority PAHs were analyzed in sediments and organisms (fish and oysters) in the estuarine-lagoon system Tuxpan-Tampamachoco, Veracruz; Mexico.The analysis of these compounds was carried out by means of gas chromatography-FID and mass spectrometry. In March (dry season) the average concentration of PAHs in sediments was 0.86 ± 0.39 μg/g and in August (rainy season) it was 1.14 ± 0.45 μg/g. During both collections, chrysene presented the highest total concentrations and a domain of the compounds with 4 benzene rings was observed, therefore, pyrolytic sources of contribution predominated. The highest concentrations of PAHs occurred in 2 stations located in the Tuxpan riverbed and both exceeded the threshold concentration to cause adverse effects to the benthic community.The analysis of PAHs in organism tissues was carried out in 4 species of fish and one mollusk. In march, the species with the highest concentration was Bagre marinus with 88.87 μg/g and in august it corresponded to the Caranx hippos species with 26.82 μg/g and the compound determined with the highest presence was benzo(b)fluoranthene.Finally, the tendency of accumulation of PAHs in the evaluated matrices was: fish> sediments> mollusks.

Helminth Parasites of Caranx hippos (Crevalle Jack) and Sardinella maderensis (Madeiran Sardinella) from Two Fishing Settlements In Okrika, Rivers State, Nigeria

Fish is an important dietary component as a source of high quality protein, and parasitic infections can result in production and economic losses. Therefore, this study was aimed at investigating the helminth parasites of Caranx hippos and Sardinella maderensis of Okrika. Fish samples were purchased from fishers between May and June, 2019 from two locations: Angalabia and Sara landing ports, Okrika. Fifty specimens of each species were dissected using standard methods, and parasites were identified using appropriate keys. Parasite ecological parameters were computed. Two parasite species were identified, Lethacotyle sp. (monogenea) and Anisakid larvae (nematode). Twenty-six specimens of Caranx hippos were infected with Lethacotyle sp., and eight with Anisakid larvae. Only one specimen of S. maderensis was infected with Anisakid larvae; others were un-infected. Examination showed a prevalence of 52.0% and 16.0% infection of Lethacotyle sp. and Anisakid larvae, respectively, in Caranx hippos, and 2.0% prevalence of Anisakid larvae in Sardinella maderensis. The preferred organs for parasite infection were the gills (Lethacotyle sp.) and intestines (Anisakid larva) of infected fish. The recovery of Anisakid larvae at a prevalence of 16% indicates that anisakiasis could be an emerging disease in Okrika. It is recommended that further research be conducted into the molecular characterization of Lethacotyle sp. of C. hippos of Okrika. It is also important to properly identify and characterize the Anisakid species, and investigate the incidence of human anisakiasis inOkrika and other coastal cities of Rivers State, Nigeria. Keywords: Lethacotyle, Anisakid larva, anisakiasis, Caranx, Sardinella, Parasites, Marine, Okrika, Nigeria

New Records of Fish Parasitic Isopods (Crustacea: Isopoda) from the Gulf of Thailand

From a total of 4140 marine fishes examined, eight species of parasitic isopods were reported from marine fishes in the Gulf of Thailand. These isopods were identified in two families, Corallanidae (Argathona macronema and Argathona rhinoceros) and Cymothoidae (Cymothoa eremita, Cymothoa elegans, Smenispa irregularis, Nerocila sundaica, Norileca indica and Norileca triangulata). Most of these parasitic isopods were found in the buccal cavity of their fish hosts with one host recorded as follows: C. eremita was found from Nemipterus hexodon, C. elegans was found from Scatophagus argus, N. sundaica was found from Saurida tumbil. The majority of the isopod specimens recorded in this study was S. irregularis, which was found in the buccal cavities of five host fish, Pampus argentius, Alepes melanoptera, Caranx hippos, Parastromateus niger and Terapon jarbua, with a prevalence of 11.67%, 10.43%, 9.78%, 6.10% and 4.21%, respectively. Argathona rhinoceros was found in the nasal cavity and branchial cavity of Epinephelus coioides, whereas A. macronema and N. triangulata were found on the skin of Epinephelus coioides and Seriolina nigrofasciata, respectively. The highest species diversity was found in E. coioides, which harbored two species of parasitic isopods, A. macronema and A. rhinoceros. Cymothoa eremita, C. elegans, S. irregularis and N. triangulata were recorded for the first time in the Gulf of Thailand. The reported discovery of C. eremita, S. irregularis, N. sundaica and N. triangulata in their fish hosts were new recorded hosts. Moreover, A. macronema and N. triangulata were found for the first time in the central Indo-Pacific region.

Fish as bioindicators of habitat degradation in coastal lagoons of Ghana

Eugenia BB, Armah AK, Dankwa HR. 2018. Fish as bioindicators of habitat degradation in coastal lagoons of Ghana. Bonorowo Wetlands 2: 9-26. Lagoons habitat forms an integral part of the marine fishing industry and provides essential spawning and nursery grounds for many fishes. Fish act as biological indicators of water quality and changes by summarizing information regarding their environment. Two lagoons, Laloi and Oyibi in the and Greater Accra and Central Regions of Ghana were studied to determine the ecological status using the Estuarine Fish Community Index (EFCI). Metrics assigned were the species diversity, nursery function, trophic integrity, and species abundance and composition. Water samples were obtained at the riverine, middle, and seaward portions during both high and low tides at each site. Fisherfolks were hired to fish at each of the sites. There are no significant differences between sites as measured by diversity indices. Multivariate analysis showed a considerable similarity between sites regarding species composition. This study identified eighteen species, including both finfish and shellfish. Two most abundant species during the study was the flathead grey mullet (Mugil cephalus) and the black-chinned tilapia (Sarotherodon melanotheron). Mugil cephalus dominated catches in the Laloi lagoon, whereas Sarotherodon melanotheron were dominant in the Oyibi Lagoon. The most dominant species collected for the Laloi lagoon were S. melanotheron, Lutjanus fulgens, and Eucinostomus melanopterus. Caranx hippos, L. fulgens, and M. cephalus constituted a significant part of fishes caught in the Oyibi lagoon. The carangid, Caranx hippos contributed primarily of the biomass of fishes collected for both lagoons. In the rainy season, total fish abundance was higher than the dry season. Chlorophyll-a concentrations and condition factor of S. melanotheron were highest at both lagoons. Total organic carbon was high in the Oyibi lagoon; hence, the high numbers of S. melanotheron recorded. Tides were an essential factor affecting physicochemical parameters. Oyibi displayed a moderate site rating, suggesting that it was under mild stress with some stress factors identified were garbage dumping, defecation, land-use changes, and increased human pressure. Meanwhile, Laloi Lagoon had a poor site rating, suggesting that it was under severe stress. The principal strains identified were overfishing, garbage dumping, mangrove degradation, and increased human settlements along the sides of the lagoon. The multi-metric index described served an effective method which reflects the status of lagoon fish communities and the overall ecosystem conditions.

Length-Weight Relationship and Condition Factor of Fish Species Caught by Cast Net in New Calabar River, Nigeria

The length -weight relationship and condition factor (K) of fish species caught by cast net were studied from three stations in the New Calabar River, Rivers State, Nigeria. A total of 1541 specimens of 26 fish species and representing 11 families were randomly collected using cast net with mesh sizes of 1.5 and 2.5 cm. Sample sizes of the different fish species examined in this study ranged from 8.79±0.25 cm (Caranx hippos specie) to 31.48±4.93 cm (Sphyraena barracuda specie) in total length and 15.45±0.40 g (Elops lacerta) to 156.00±39.30 g (Pelmatolapia mariae) in weight. The entire length-weight data in all the three stations were pooled together and the calculated correlation coefficient showed a high positive correlation (1.00) between length and weight of all the fish species except in Caranx hippos (0.18) with low positive correlation. The b value obtained ranged from 2.13 for Ethmalosa fimbriata with negative allomerty to 3.53 for Pelmatolapia mariae with positive allometry. By negative allometry (b < 3), the fish is said to be lighter for its length as it grows and (b>3), the fish gains weight as it grows. The mean condition factor ranged from 0.36 ± 0.03 recorded for Sphyraena barracuda to 2.20 ± 0.02 for Coptodon guineensis and Coptodon zillii. Apart from Sphyraena barracuda general wellbeing of all the fish species were found to be good, as indicated by the values of condition factor, which were nearer to or greater than 1. The results of the present study will provide an effective tool for further studies of population dynamics and stock assessment studies in the study area.

Genetic variation and genetic structure of Caranx hippos (Teleostei: Carangidae) in the Colombian Caribbean

Studies based on molecular genetics offer the possibility to understand the structure of populations and provide data to implement measures designed to protect them. Caranx hippos, is a fish with a wide distribution in the Western Atlantic, becoming one of the most economically important species in the artisanal fishing industry in Colombia. However, little is known about its biology. The present study aimed to evaluate the variation and genetic structure of C. hippos in the Colombian Caribbean by analyzing the mitochondrial DNA region control and cytochrome oxidase subunit (COI). We sequenced the DNA of 153 muscle samples collected from specimens obtained from six fishing ports. The results showed 21 haplotypes for COI and 116 haplotypes for the control region, divided into two lineages that do not exhibit a pattern of geographical distribution. For mitochondrial control region, the estimated haplotype diversity (Hd) presented relatively high values (Hd = 0.99 and = 0.1), while for COI results were Hd = 0.68 and = 0.01; the relationship between haplotype and nucleotide diversity and the neutrality test revealed that C. hippos experienced bottlenecking and a subsequent rapid population expansion. Estimates of genetic structure were low and insignificant, indicating no differentiation between samples collected from geographical isolation. This suggests that for the Colombian Caribbean there is a panmictic population of C. hippos. However, variations were found at population levels, especially in La Guajira, Turbo and San Antero, which, when compared to those included for Brazil and México, demonstrated that unique haplotypes in La Guajira are more aligned to the Brazilian populations, by means of the influence of the Caribbean Current, whilst those from Turbo and San Antero are more frequent in haplotypes originating from Mexico. Future studies should focus the understanding of these processes.

CHARACTERIZATION OF ARTISANAL FISHING IN FISHWEIRS, THE NORTH COAST OF PARAIBA, BRAZIL

Estratégias tradicionais de pesca são utilizadas por comunidades de pescadores em todo o mundo, dentre elas os “currais”, que são armadilhas fixas construídas na zona costeira. O objetivo do presente estudo foi caracterizar e descrever as formas de manejo destes “currais” pelos pescadores do litoral da Paraíba. Foram utilizadas entrevistas livres, “rapport”,“Snow ball” e formulário semiestruturado nas visitas mensais aos cinco “currais” entre os meses de novembro 2012 até março de 2013. Foi quantificada a produção dos currais e identificada as espécies mais capturadas. Os dados mostraram que estas armadilhas são constituídas por compartimentos e passam por fases em terra e mar até serem totalmente ativadas. O total da produção de peixes foi de 303 kg. As espécies predominantes foram: Mugil curema and Mugil liza, Trichiurus lepturus, Caranx hippos, Selene vomer, Selene setapinnis, Diapterus auratus e Diapterus rhombeus. Conclui-se que este tipo de pesca é utilizado há décadas no litoral da Paraíba, demonstrando existir manejo e técnicas próprias com relações de trabalhos inerentes a este tipo de armadilha.