Caranx Hippos Research Articles

Microplastics in the Digestive Tracts of Four Fish Species from the Ciénaga Grande de Santa Marta Estuary in Colombia

This study investigated the presence of microplastics (MPs) in the gastrointestinal tracts of four fish species from the estuarine Cienaga Grande de Santa Marta (CGSM) in northern Colombia. Of the 140 fish purchased at a local market, 17 (12.1%) were found to contain MPs as confirmed by FT-IR analysis. Among the four different species, Mugil incilis (mullet) showed the highest MP prevalence with just over a fifth of the individuals containing MPs in their gastrointestinal tracts (10 out of 46 (frequency of MP occurrence in %) FO% = 21.7%). This was followed by Caranx hippos (crevalle jack, 2 out of 19 (FO% = 10.5%)), Caquetaia kraussii (yellow mojarra, 3 out of 35 (FO% = 8.6%)), and Eugerres plumieri (striped mojarra, 2 out of 40 (FO% = 5.0%)). From the 17 fish, only 19 MPs were found of which 17 (89.5% were fibers) and 2 (10.5%) were fragments. While polyester and polyethylene were the most common fibers, nylon, acrylic, polyethylene, and modacrylic were also identified suggesting a wide variety of origins and sources. These finding provide the first evidence of MP ingestion by resident fish species in Colombian estuarine waters. Since the region has been variously recognized as being of regional and international importance (i.e., RAMSAR site in 1998 and UNESCO Biosphere Reserve in 2000), we advocate the ongoing investigation of MP pollution in both the environment and biota.

Fish as bioindicators of habitat degradation in coastal lagoons of Ghana

Abstract. 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.

Large-scale assessment of mercury in sentinel estuarine fishes of the Florida Everglades and adjacent coastal ecosystems

In Florida, USA, mercury can bioaccumulate in aquatic food webs to levels that are harmful to human and ecosystem health. Proposed efforts to restore hydrological flow in the Florida Everglades, which encompasses projects throughout central and south Florida, may alter the spatial distribution and temporal trends in mercury bioaccumulation in Florida fish populations. Monitoring of mercury in sentinel fish species permits assessment of changing conditions and can identify natural or anthropogenic impacts on upstream watersheds and predict regional influences on human and wildlife consumers of these fish species. From 2006 through 2008, we assessed total mercury in muscle of 545 gray snapper, Lutjanus griseus (Linnaeus, 1758), and 381 crevalle jack, Caranx hippos (Linnaeus, 1766), from 13 broad estuarine regions in central and south Florida, downstream of proposed Everglades restoration projects. For comparison, we assessed an additional 134 gray snapper collected from adjacent offshore waters in the Gulf of Mexico in 2007–2008 and 2014–2015. Collectively, these results indicate that Florida Bay and Card and Barnes sounds are mercury hot spots for both fish species in Florida estuarine and coastal ecosystems. Mean mercury concentrations in these species from Florida Bay were 1.7–2.5 times those measured in Atlantic coast estuaries (i.e., Loxahatchee estuary, St. Lucie estuary, and Indian River Lagoon). Mercury in snapper from offshore gulf waters did not reveal spatial differences from adjacent coastal estuaries, but did suggest concentrations in offshore snapper have remained stable in recent years. These results provide comprehensive baseline data that can be used to identify mercury hot spots in south Florida and for monitoring temporal and spatial changes in estuarine and coastal mercury concentrations as Everglades restoration plans are implemented.

DNA barcoding, fisheries and communities: What do we have? Science and local knowledge to improve resource management in partnership with communities in the Colombian Caribbean

Human communities living around Cartagena Bay (Colombian Caribbean) depend on fishing activities as their main income and food source. This resource has been affected by pollution, sedimentation and overfishing. DNA barcoding was used for fish species identification, and the genetic diversity and population structure of two valued fish genera, snappers (Lutjanus spp.) and jacks (Caranx spp.) from the main fishing grounds in the area was evaluated. Fishermen collected tissue samples and measured size and weight and capture location for each fish. A 700 base pairs (bp) fragment of the mitochondrial Cytochrome Oxidase I (COI) was sequenced for 104 samples (55 snappers and 49 jacks). Comparisons against Genbank allowed identification of eight species: Lutjanus synagris, L. apodus, L. jocu, L. cyanopterus, L. analis, Caranx hippos, C. latus and C. crysos. Genetic diversity for the fish around the Colombian Caribbean sampling locations was relatively high in comparison to those of other populations and population differentiation was significant for some species, particularly for L. synagris and L. apodus, suggesting that the fish from the Colombian Caribbean belong to an independent stock. Mean body length for all species was significantly smaller than body length at maturity, indicating that all fish captured were immature. Levels of genetic diversity appear to be high in these fish populations. The fact that fishermen are capturing immature fish is worrisome, suggesting the need to improve management of fish populations and the need to include the communities in conservation planning for the Islas del Rosario National Natural Park.

Evaluation of Mercury, Lead, Arsenic, and Cadmium in Some Species of Fish in the Atrato River Delta, Gulf of Urabá, Colombian Caribbean

The concentrations of mercury, lead, cadmium, and arsenic were evaluated in 96 samples, 12 by each one of the following eight fish species: snook (Centropomus undecimalis), crevalle jack (Caranx hippos), Serra Spanish mackerel (Scomberomorus brasiliensis), southern red snapper (Lutjanus purpureus), blue runner (Caranx crysos), Atlantic tarpon (Megalops atlanticus), ladyfish (Elops saurus), and Atlantic goliath grouper (Epinephelus itajara), which were collected during 1 year in the Atrato River Delta in the Gulf of Uraba, Colombian Caribbean. Three fish were caught from each of the following sites the community usually uses to catch them (known as fishing grounds): Bahia Candelaria, Bahia Marirrio, Bocas del Roto, and Bocas del Atrato. The quantification of metals was performed by microwave-induced plasma-optical emission spectrometry. The Pb concentration fluctuated from 0.672 to 3.110 mg kg−1, surpassing the maximum permissible limit (MPL = 0.3 mg kg−1) for human consumption for all species. The Hg concentration ranged between < Limit of detection and 6.303 mg kg−1, and in the crevalle jack and Atlantic tarpon, concentrations exceeded the MPL (0.5 mg kg−1). The levels of Cd and As were not significant in the studied species and did not exceed the MPL (0.05 mg kg−1).

Elemental ratios and lipid classes in a coral reef food web under river influence

Coral reefs in the Caribbean and Gulf of Mexico are increasingly suffering from anthropogenic nutrient inputs principally from fertilizers as identified by their δ15N signatures. To determine if primary producers are passively affected by anthropogenic nitrogen enrichment in a coral reef community, carbon: nitrogen ratios (C:N mol mol−1) were measured. The C:N ratio was used as a proxy for nitrogen enrichment in primary producers when the ratio decreases, and for lipid plus carbohydrate in terms of C, and protein in terms of N in primary producers and consumers. Lipid classes and the triacylglycerol to sterol (TAG:ST) ratio were used to evaluate energy storage as an indication of nutritional quality in the six most abundant primary producers, and of nutritional condition in ten ubiquitous consumers in a coral reef in the Gulf of Mexico under river influence. A low C:N ratio revealed nitrogen enrichment in primary producers. Among the lipids, high TAG proportions were detected in phytoplankton and zooxanthellae suggesting that they have a higher nutritional quality in terms of energy, followed by sea grass, mangrove, and macroalgae. During the rainy season TAG:ST increased in primary consumers such as echinoderms, and top predators such as the perciform fish Bodianus rufus, Ocyurus chrysurus and Caranx hippos, suggesting an increase in energy storage. In contrast, TAG:ST decreased in the principal habitat providing coral Montastrea cavernosa, along with a decrease in the phospholipid proportion suggesting a poor nutritional condition. There were three species with no change in their TAG:ST ratio: the sponge Aplysina sp., the masked goby Coryphopterus personatus and the surgeon fish Achanturus chirurgus. The lower value of TAG, TAG:ST ratio and phospholipid proportion in the coral M. cavernosa suggests that the reported abundance of zooplankton does not satisfy the energy demand of M. cavernosa during the rainy season.

Trophic flow structure of a neotropical estuary in northeastern Brazil and the comparison of ecosystem model indicators of estuaries

Abstract We developed an Ecopath model for the Estuary of Sirinhaem River (SIR), a small-sized system surrounded by mangroves, subject to high impact, mainly by the sugar cane and other farming industries in order to describe the food web structure and trophic interactions. In addition, we compared our findings with those of 20 available Ecopath estuarine models for tropical, subtropical and temperate regions, aiming to synthesize the knowledge on trophic dynamics and provide a comprehensive analysis of the structures and functioning of estuaries. Our model consisted of 25 compartments and its indicators were within the expected range for estuarine areas around the world. The average trophic transfer efficiency for the entire system was 11.8%, similar to the theoretical value of 10%. The Keystone Index and MTI (Mixed Trophic Impact) analysis indicated that the snook (Centropomus undecimalis and Centropomus parallelus) and jack (Caranx latus and Caranx hippos) are considered as key resources in the system, revealing their high impact in the food web. Both groups have a high ecological and commercial relevance, despite the unregulated fisheries. As result of the comparison of ecosystem model indicators in estuaries, differences in the ecosystem structure from the low latitude zones (tropical estuaries) to the high latitude zones (temperate system) were noticed. The structure of temperate and sub-tropical estuaries is based on high flows of detritus and export, while tropical systems have high biomass, respiration and consumption rates. Higher values of System Omnivory Index (SOI) and Overhead (SO) were observed in the tropical and subtropical estuaries, denoting a more complex food chain. Globally, none of the estuarine models were classified as fully mature ecosystems, although the tropical ecosystems were considered more mature than the subtropical and temperate ecosystems. This study is an important contribution to the trophic modeling of estuaries, which may also help the knowledge of the role of key ecosystem processes in SIR.

Evaluation of mercury, lead, and cadmium in the waste material of crevalle jack fish from the Gulf of Urabá, Colombian Caribbean, as a possible raw material in the production of sub-products.

The Gulf of Urabá, currently considered a national strategic ecoregion, could be threatened by the presence of heavy metals such as mercury (Hg), lead (Pb), and cadmium (Cd), which directly affect the aquatic ecosystem. In Colombia, investigations on marine species pollution are scarce; however, their products are consumed. The aim of this study was to quantify the contents of Hg, Pb, and Cd in muscle and in waste material (head-gills, viscera, fins-tail), in one of one of the most commercialized resources, the crevalle jack (Caranx hippos), and to determine their presence in some of the body portions that are used in the production of sub-products. The concentrations of Hg, Pb, and Cd were compared between the waste material and muscle of the crevalle jack fish that were caught from each of the following sites the community usually uses to catch them: Bahía Candelaria, Bahía Marirrío, Bocas del Roto, and Bocas del Atrato. They were captured every 1year in each climatic period. All body portions exceeded the maximum allowed limits for Pb (0.667-23.378mgkg-1); the highest Hg concentrations were found in muscle (0.515-7.019mgkg-1) and viscera (0.172-1.883mgkg-1), and for Cd, the parts with the highest levels were the fins-tail (0.040-0.15mgkg-1) and viscera (0.040-0.174mgkg-1). Considering the obtained results, it is not recommended to use the waste material for the production of fish meal or fish silage due to the adverse effects it could cause on both animals and humans.

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.

Predatory pelagic fishes of the Bijagós Archipelago (Guinea-Bissau) show high overlap in diets dominated by sardinella

Knowledge of trophic interactions between the key components of marine communities is required to understand food-web dynamics and develop ecosystem-based management approaches. In West Africa, where fisheries sustain the livelihoods of a significant part of the human population, this understanding is even more urgent, especially in the face of rapidly expanding fisheries and some stock collapses in the region. We studied the feeding ecology of the Crevalle jack Caranx hippos, West African Spanish mackerel Scomberomorus tritor and Guinean barracuda Sphyraena afra in the Bijagós Archipelago, Guinea-Bissau. These are the most abundant pelagic predatory teleost fishes in the area, but little is known about their ecology despite being species with commercial and recreational value, and they likely also play an important role in various African coastal ecosystems. Our findings show a high degree of dietary overlap among these three predator species, despite some degree of segregation by prey size and type. All three predators depend on Sardinella maderensis as the most important prey, which together with other members of the Clupeidae represented 47–96% of the ingested prey items. There was little difference in the diets of the predators between the dry and rainy seasons. These novel findings suggest a ‘wasp-waist’-structured ecosystem in the Bijagós Archipelago in which S. maderensis is the central small-sized pelagic fish species, and stress the need for an ecosystem-based approach to fisheries management in the region, with precautionary measures taken to avoid the overexploitation of clupeids.

Computational analysis of vortex dynamics and performance enhancement due to body–fin and fin–fin interactions in fish-like locomotion

Numerical simulations are used to investigate the hydrodynamic benefits of body–fin and fin–fin interactions in a fish model in carangiform swimming. The geometry and kinematics of the model are reconstructed in three-dimensions from high-speed videos of a live fish, Crevalle Jack (Caranx hippos), during steady swimming. The simulations employ an immersed-boundary-method-based incompressible Navier–Stokes flow solver that allows us to quantitatively characterize the propulsive performance of the fish median fins (the dorsal and the anal fins) and the caudal fin using three-dimensional full body simulations. This includes a detailed analysis of associated performance enhancement mechanisms and their connection to the vortex dynamics. Comparisons are made using three different models containing different combinations of the fish body and fins to provide insights into the force production. The results indicate that the fish produces high performance propulsion by utilizing complex interactions among the fins and the body. By connecting the vortex dynamics and surface force distribution, it is found that the leading-edge vortices produced by the caudal fin are associated with most of the thrust production in this fish model. These vortices could be strengthened by the vorticity capture from the vortices generated by the posterior body during undulatory motion. Meanwhile, the pressure difference between the two sides of posterior body resulting from the posterior body vortices (PBVs) helps with the alleviation of the body drag. The appearance of the median fins in the posterior region further strengthens the PBVs and caudal-fin wake capture mechanism. This work provides new physical insights into how body–fin and fin–fin interactions enhance thrust production in swimming fishes, and emphasizes that movements of both the body and fins contribute to overall swimming performance in fish locomotion.

Iron, Copper, and Zinc in Some Fish Species of the Atrato River Delta, Colombian Caribbean

ABSTRACTThe concentrations of iron (Fe), copper (Cu), and zinc (Zn) were evaluated in 96 samples of the following eight fish species: Centropomus undecimalis, Caranx hippos, Scomberomorus brasiliensis, Lutjanus purpureus, Caranx crysos, Megalops atlanticus, Elops saurus, and Epinephelus itajara collected in the Atrato River Delta in the Gulf of Urabá. Three fish were caught from each of the following common fishing grounds: Bahía Candelaria, Bahía Marirrío, Bocas del Roto, and Bocas del Atrato. Fish were captured during a one-year period, with one specimen per species in each climatic period: dry, transient, and wet. The quantification was performed by microwave plasma-atomic emission spectroscopy. The highest levels of Fe and Cu were found in Caranx crysos, and highest level of Zn in Megalops atlanticus. According to the percentage of the daily value per food serving, Caranx crysos and Caranx hippos are good sources of Fe, and Caranx crysos is a good source of Cu.

The bone degenerative processes in senile fishes from Holocene Brazilian shell mounds.

Zooarchaeological collections from shell mounds in Rio de Janeiro (2,470-4,632cal BP) contain a high prevalence of swollen fish bones belonging to the Atlantic spadefish (Chaetodipterus faber), crevalle jack (Caranx hippos) and fat snook (Centropomus parallelus). Given the lack of knowledge of the bone degenerative process in senile fishes, this study analysed hyperostotic bone in zooarchaeological and modern specimens to obtain high-resolution morphology and microstructure reconstruction. We used microCT as well as X-ray diffraction to characterize the crystallographic changes associated with fish senility. Our results showed that trabecular microstructures in hyperostotic bones were consistent with estimated values of the per cent bone volume-to-total volume ratio (BV/TV) and were greater than 60% in cortical bone. Hyperostotic bones indicated a high radiograph density, and X-ray diffractograms showed a decrease in hydroxyapatite [Ca10 (PO4 )6 (OH)2 ] and calcite (CaCO3 ) neocrystallization. These crystalline and density changes revealed an advanced stage of fish senile and indicate the vulnerability of ageing fish populations.

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.

Selective predation by crevalle jack Caranx caninus on engraulid fishes in the SE Gulf of California, Mexico

Feeding habits determine many aspects of living organisms, where it lives, the time of day that it is active, energy flow, biomass consumed and intra- and interspecific interactions, it which provides information to make predictions about the effects of fisheries on predator-prey relationships. Accurate predictions require a thorough understanding of predator diets and prey selection. In this study, specimens of the crevalle jack Caranx caninus were obtained between October 2012 and October 2014 in the SE Gulf of California, Mexico, in order to determine its feeding habits and prey selection. A total of 238 specimens were obtained, of which 94 (39.5%) had stomachs containing food and 144 (60.5%) had empty stomachs. A total of 10 prey items were identified, corresponding to seven families that included fishes, crustaceans and cephalopods. According to the Index of Relative Importance (IRI) the most important prey were Anchoa spp. (IRI = 91.2%), Engraulis mordax (IRI = 1.8%), and fish from the Clupeidae family (IRI = 1.0%). The crevalle jack’s diet did not change with the season (warm or cold). The crevalle jack was considered a tertiary predator (trophic level = 4.3) that tends to feed on a reduced number of prey, characterizing it as a specialist and selective predator of engraulid fishes (Levin’s index, Bi = 0.08; E = 0.6).

Influence of oceanographic conditions on abundance and distribution of post‐larval and juvenile carangid fishes in the northern Gulf of Mexico

AbstractRelationships between abundance of post‐larval and juvenile carangid (jacks) fishes and physical oceanographic conditions were examined in the northern Gulf of Mexico (GoM) in 2011 with high freshwater input from the Mississippi River. Generalized additive models (GAMs) were used to explore complex relationships between carangid abundance and physical oceanographic data of sea surface temperature (SST), sea surface height anomaly (SSHA) and salinity. The five most abundant carangid species collected were: Selene setapinnis (34%); Caranx crysos (30%); Caranx hippos (10%); Chloroscombrus chrysurus (9%) and Trachurus lathami (8%). Post‐larval carangids (median standard length [SL] = 10 mm) were less abundant during the spring and early summer, but more abundant during the late summer and fall, suggesting summer to fall spawning for most species. Juvenile carangid (median SL = 23 mm) abundance also increased between the mid‐summer and early fall. Most species showed increased abundance at lower salinities and higher temperatures, suggesting entrainment of post‐larval fishes or feeding aggregations of juveniles at frontal convergence zones between the expansive river plume and dynamic mesoscale eddy water masses. However, responses were species‐ and life‐stage specific, which may indicate fine‐scale habitat partitioning between species. Ordination methods also revealed higher carangid abundances at lower salinities for both post‐larval and juvenile life stages, with species‐ and life‐stage specific responses to SST and SSHA, further suggesting habitat separation between species. Results indicate strong links between physical oceanographic features and carangid distributions in the dynamic northern GoM.

Concentration and Human Health Implications of Trace Metals in Fish of Economic Importance in Lagos Lagoon, Nigeria.

Background.The most significant sources of food-borne diseases are microbiological and chemical hazards. The health risk due to consumption of food from aquatic ecosystems contaminated with hazardous chemicals including metals has increased globally, especially in developing countries like Nigeria.Objectives.The concentration and human health implications of trace metals in fish of economic importance in Lagos lagoon were investigated by determining the degree of contamination with heavy metals of selected fish from Lagos lagoon and assessing the possible health risks associated with fish consumption.Methods.Fish of economic importance including Caranx hippos, Chrysichthys nigrodigitatus, Elops lacerta, Galeoides decadactylus, Ilisha africana, Liza falcipinnis, Lutjanus goreensis, Mugil cephalus, Pseudotolithus senegalensis, Sarotherodon spp, Sphyraena spp, and Tilapia spp were bought from fishermen fishing in Lagos lagoon. The fish tissue samples were digested and analyzed in five replicates for heavy metals (lead, cadmium, iron, manganese and zinc) using a Varian AA600 atomic absorption spectrometer.Results.There were considerable variations in the concentrations of heavy metals among different species. The twelve fish species collected from Lagos lagoon were found to contain various concentrations of heavy metals and the levels of accumulation of these heavy metals varied across different species. Lead, cadmium, and manganese were present in all the studied fish species at higher concentrations than the maximum allowable concentrations in fish recommended by the Food and Agricultural Organization (FAO) and World Health Organization (WHO). The target hazard quotient (THQ) estimated for individual heavy metals through consumption of different fish species was less than 1 for all individual heavy metal in all the fish species.Conclusions.Controls on the dumping of wastes in the lagoon are needed, along with regular monitoring. Currently, no potential non-carcinogenic health risks from ingestion of a single heavy metal through consumption of these fish species was found.

Notes on fishes from the Gulf of Nicoya, Costa Rica

From March 1951 through March 1953, I fished for the market in Puno tarenas and collected more than 500 fish specimens and 70 species for the Field Museum of Natural History. This paper concerns information on life histories, migrations, habits and ecology of marine fishes. Of particular interest are notes on blacktip, hammerhead and bonnethead sharks; sawfish, stingrays and mantas; sea catfishes, floating cIingfish, crevalle jack, corbina, sierra and Pacific bonito.

Length- Weight Relationships and Condition Factors of Cynoglossus Cynoglossus and Caranx Hippos in Epe Lagoon, Nigeria

Length- Weight Relationships and Condition Factors of Cynoglossus Cynoglossus and Caranx Hippos in Epe Lagoon, Nigeria