Caranx Hippos Research Articles

Mixed-marker data indicate the population biology, history, and the stock structure of crevalle jack Caranx hippos (Linnaeus, 1766) in the tropical Atlantic: A regional and latitudinal conservation genetics approach

The crevalle jack Caranx hippos (Carangidae: Caranginae) is a commercially important carangid, especially along the Brazilian Northeastern coast. However, little is known about its population structure and genetic diversity, which is crucial information for species conservation. Using mitochondrial [barcode region COI and control region] and nuclear (first intron S7) data, we investigated the genetic structure and demographic history of C. hippos along the Brazilian Northeastern coast, and included the COI public database to provide a latitudinal approach. Both mitochondrial markers revealed two coexistent lineages along the Brazilian Northeastern coast, while the nuclear DNA did not recover any signals of structure. This mitonuclear discordance can be explained by both male dispersal and demographic history, which seem to be closely related to the Pleistocene period. Over the glacial cycles, the lineages may have used different refuges, regaining contact during the interglacial cycles. This hypothesis of previous allopatry is reinforced by the profound genetic distance found. The latitudinal approach reveals a deep differentiation between the Carolina and both Brazilian and Caribbean Provinces, with high and significant FST pairwise values, such that the tropical-temperate climate transition may be acting as a gene flow barrier between them. Thus, we suggest two preliminary stocks for C. hippos in the Atlantic: (1) Carolina and (2) Brazilian and Caribbean Provinces.

Seasonality, distribution, and harvest trends of Crevalle Jack in Texas

AbstractObjectiveCrevalle Jack Caranx hippos are important coastal predators and support an increasingly popular catch‐and‐release sport fishery. However, population declines have recently been perceived by stakeholders in parts of the species' range. Here, we aimed to provide distribution and harvest trends for Crevalle Jack in the northwestern Gulf of Mexico.MethodsLong‐term fishery‐independent and fishery‐dependent data were collected by the Texas Parks and Wildlife Department from 1983 to 2021. Bag seine, bay trawl, and gill‐net samples were collected in conjunction with angler creel surveys. Crevalle Jack that were observed in fishery‐independent sampling were used to assess patterns in both juvenile and adult relative abundance, distribution, and seasonality. In addition, boosted regression tree models were used to highlight important predictors of Crevalle Jack presence. Crevalle Jack harvest observed during angler surveys was used to describe the fishery, including differences in inshore and offshore catch patterns. Relative abundance of both juveniles and adults was variable across years but displayed no trend throughout the time series.ResultCrevalle Jack of all sizes were found within inshore waters, with subadults and large adults particularly reliant on estuarine systems. Recruitment peaked in early summer, with juveniles occupying all major estuaries along the coast. Shifts in recruitment were evident in bag seines, as the mean date of catch trended almost 2 weeks earlier over the study period. The Crevalle Jack fishery was spread across inshore and offshore waters, with significantly larger fish harvested offshore during summer. The majority of anglers who harvested Crevalle Jack stated that they were specifically targeting other species, thus supporting the notion that the targeted fishery is mainly catch and release.ConclusionAs Crevalle Jack declines have been noted elsewhere in the species' range, these results could help to inform future management decisions in Texas.

Rapid approach for assessing an unregulated fishery using a series of data‐limited tools

AbstractObjectiveFisheries provide countless benefits to human populations but face many threats ranging from climate change to overfishing. Despite these threats and an increase in fishing pressure globally, most stocks remain unassessed and data limited. An abundance of data‐limited assessment methods exists, but each has different data requirements, caveats, and limitations. Furthermore, developing informative model priors can be difficult when little is known about the stock, and uncertain model parameters could create misleading results about stock status. Our research illustrates an approach for rapidly creating robust initial assessments of unregulated and data‐limited fisheries without the need for additional data collection.MethodsOur method uses stakeholder knowledge combined with a series of data‐limited tools to identify an appropriate stock assessment method, conduct an assessment, and examine how model uncertainty influences the results. Our approach was applied to the unregulated and data‐limited fishery for Crevalle Jack Caranx hippos in Florida.ResultResults suggested a steady increase in exploitation and a decline in stock biomass over time, with the stock currently overfished and undergoing overfishing. These findings highlight a need for management action to prevent continued stock depletion.ConclusionOur approach can help to streamline the initial assessment and management process for unregulated and data‐limited stocks and serves as an additional tool for combating the many threats facing global fisheries.

How wavelength affects hydrodynamic performance of two accelerating mirror-symmetric undulating hydrofoils

Fish schools are capable of simultaneous linear acceleration. To reveal the underlying hydrodynamic mechanism, we numerically investigate how Reynolds number Re=1000–2000, Strouhal number St=0.2–0.7, and wavelength λ=0.5–2 affect the mean net thrust and net propulsive efficiency of two side-by-side hydrofoils undulating in anti-phase. In total, 550 cases are simulated using immersed boundary method. The thrust increases significantly with the wavelength and the Strouhal number, yet only slightly with the Reynolds number. We apply a symbolic regression algorithm to formulate this relationship. Furthermore, we find that mirror-symmetric schooling can achieve a net thrust more than ten times that of a single swimmer, especially at low Reynolds numbers. The highest efficiency is obtained at St=0.5 and λ=1.2, where St is consistent with that observed in the linear-accelerating natural swimmers, e.g., Crevalle jack. Six distinct flow structures are identified. The highest thrust corresponds to an asymmetric flow pattern, whereas the highest efficiency occurs when the flow is symmetric with converging vortex streets.

Building a Teleost Fish Traceability Program Based on Genetic Data from Pacific Panama Fish Markets.

Fish tissue samples from 203 adult individuals were collected in the main ports and markets of the Pacific coast of Panama. Molecular identification based on a cytochrome oxidase I gene segment of all species was verified by GENBANK reference sequences. A total of 34 species from 14 families (Ariidae, Caranjidae, Centropomidae, Gerreidae, Haemulidae, Lobotidae, Lutjanidae, Malacanthidae, Mugilidae, Scianidae, Scombridae, Serranidae, Sphyraenidae, Stromateidae) were identified at the species level from 164 sequences. Additionally, three Caribbean species were molecularly identified among the analyzed samples (Mycteroperca xenarcha, Paralonchurus brasilensis and Lobotes surinamensis). Species diversity was slightly higher in the Gulf of Panama than in the Gulf of Chiriquí. For species with five or more individual sequences, genetic diversity and genetic connectivity parameters such as total number of haplotypes (H), haplotype diversity (Hd), and nucleotide diversity (π) were calculated. Overall, pelagic-migratory species showed higher values of genetic diversity than coastal and estuarine species with some exceptions. Connectivity between Gulf areas was compared using values of genetic distances and genetic differentiation (Fst). The high level of connectivity observed between the Gulf of Chiriqui and the Gulf of Montijo indicates the existence of a single stock in that area for the following species: Scomberomorus sierra, Caranx caninus and Lutjanus guttatus. The demographic history of the most common species was examined using Tajima's D values, suggesting population expansion for two snapper species, L. peru and L. argentiventris, having significant and higher values. Another important contribution from this research was the production of primers and dual-labeled probes for environmental DNA detection using qPCR for the five most abundant species (spotted rose snapper, yellow snapper, green jack, Pacific crevalle jack and the Pacific sierra fish). These markers represent a new set of tools for environmental DNA (eDNA) detection and molecular traceability of three commercially important fish species along the supply chain including landing sites and markets of the main fishery areas.

Heavy metals in crevalle jack, Caranx hippos, and their non-intestinal parasitic helminths from Playa las Barrancas, Alvarado, Veracruz, Mexico

In nine Caranx hippos specimens, Cd, Pb, Cr, and Cu concentration was determined in tissues (muscle and gonad) and parasites (nematodes and cestodes). The fish were caught from February to June 2019 in Las Barrancas, Alvarado Beach, Veracruz, Mexico. Heavy metals were quantified using atomic absorption spectrophotometer. The results of the average concentration of pollutants were, Cr = 0.18 ± 0.05 mg kg-1 dry weight (dw); Cu = 0.2 ± 0.1 mg kg-1 dw; Pb = 0.022 ± 0.01 mg kg-1 dw; Cd = <0.003 mg kg-1 dw. Among the tissues, Cu was the one with the highest concentration in nematodes vs. cestodes (2.2:1); vs. gonad (2.5:1); vs. muscle (2.7:1). Due to the concentration registered in Caranginema americanum nematodes could be identified as a bioindicator species for Cu pollutant. The values generally do not exceed the limits established in the Mexican National Standard (NOM-242-SSA1-2009) for Cd and Pb (0.5 mg kg-1). Records of heavy metals do not represent a health risk from consuming C. hippos.

Length-Weight Relationship and the Condition Factor of some Important Estuarine Fish Species from Kakum Estuary of Ghana

This study assessed the length-weight relationships and the condition factors of nine commercial and abundant fish species namely Liza dumerilli, Mugil curema, Liza falcipinnis, Mugil bananensis, Lutjanus goreensis, Lutjanus fulgens, Sardinella aurita, Caranx hippos, and Eucinostomus melanopterus from the Kakum River Estuary. This study was conducted from November 2016 to April 2017 to provide primary information about the biometrics, the length-weight model parameters, and the state of well-being of fish species inhabiting the Kakum Estuary. Sampling was done monthly using a mini boat of 9 m long with a depth of 1.5 m for both diurnal (06:00, 10:00, 14:00, 18:00, 06:00 h) and nocturnal (22:00, 02:00 h) periods with a medium-mesh cast net of 20 mm stretched. Sampling was done within thirty (30) minutes on all sampling times. The total length of the species from the estuary ranged from 2.2 cm in Liza dumerilli to 29.8 cm in Mugil curema while the total weight ranged from 0.2 g to 251 g in Mugil curema. The slope b values of the species varied from 2.3787 for Liza dumerilli to 3.1009 for Eucinostomus melanopterus. Three species from the Kakum Estuary exhibited negative allometric growth and 6 species were growing isometrically. The mean condition factors of the fish species ranged from 0.82 ± 0.36 (SD) in Sardinella aurita to 1.82 ± 0.23 (SD) in Lutjanus goreensis. The results of the present study provide essential input parameters for further assessment of the species standing stock biomass.

Redescription of Lernaeenicus longiventris Wilson, 1917 (Copepoda: Pennellidae) Parasitic on the Pacific Crevalle Jack Caranx caninus (Carangidae) Through Morphological and Molecular Analyses.

The present study deals with a redescription of the copepod Lernaeenicus longiventris Wilson, 1917 (Copepoda: Siphonostomatoida: Pennellidae) found on the Pacific crevalle jack Caranx caninus Günther, using morphological and molecular analyses. Fish were collected off Mazatlán Port (23° 12' N, 106° 26' W), in the State of Sinaloa, Mexico (southeastern Gulf of California). The copepods were morphologically analyzed by light microscopy. Sequences of the COI mtDNA gene were generated for the first time for this species. These sequences were compared to COI sequences from six species of Lernaeenicus available in GenBank. The specimens of the present study exhibited a cephalosome without apparent lateral processes, which were originally described for L. longiventris. No remarkable differences were observed with previous descriptions regarding appendages and body proportions. The phylogenetic tree based on COI sequences showed that L. longiventris was closer to L. radiatus although with low bootstrap values support in ML tree, both species formed a sister clade of L. sprattae. Lernaeenicus longiventris is the unique species of the genus in the Mexican Pacific and the Gulf of California, and also the unique species of Lernaeenicus infecting C. caninus. Molecular data of L. longiventris from host and locality type are required to avoid misidentification of this species.

Differential Presence of Microplastics and Mesoplastics in Coral Reef and Mangrove Fishes in Isla Grande, Colombia

This study aims to determine whether differences exist between the presence of microplastics and mesoplastics in fishes of coral reef and mangrove ecosystems, in Isla Grande, Colombian Caribbean. The collection of three species of coral reef (Centropomus undecimalis, Caranx hippos, and Lutjanus synagris) and three species of mangrove from coral reef (Centropomus undecimalis, Eugerres plumieri, and Archosargus rhomboidalis) were found to have ingested microplastics and mesoplastics, with a significantly higher in the mangrove species than in the coral reef species (1.9 vs. 1.6 items/individual). Furthermore, the average abundance and weight of microplastics and mesoplastics were significantly higher in females than in males (p < 0.05) and the abundance of microplastics and mesoplastics in the intestines was significantly higher than in the stomach (p < 0.05). PE, polyester, PVC, and PET were the most abundant polymers among common plastics found in species of the two habitats. Our findings highlight the importance of more rigorous plastic waste management strategies in areas nearby the coast and mangrove habitats.

Age, growth and diet of crevalle jack (Caranx hippos) in the Gulf of Mexico

AbstractThe goals of this study were to generate baseline population dynamics parameters for Gulf of Mexico crevalle jack Caranx hippos and examine the foraging habits of Mississippi and Alabama crevalle jack. Specimens were collected from Mississippi, Alabama and Florida, and age was estimated from sagittal otoliths. Stomachs from some specimens were retained for dietary analyses. Age classes spanned 0–20 years. Overall growth was best represented by the logistic growth model, whereas sex‐specific growth was best represented by a version of the von Bertalanffy growth function that allowed L∞ to vary by sex while holding k and t0 constant between sexes. Fishes were more important to crevalle jack diet than invertebrates, and diet varied among locations and years. These findings will address fundamental knowledge gaps to inform age‐based stock assessments for crevalle jack and ecosystem approaches to fisheries management in the Gulf of Mexico.

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.

Bottom-up conservation: using translational ecology to inform conservation priorities for a recreational fishery

Translational ecology defines a collaborative effort among scientists and stakeholders to rapidly translate environmental problems into action. This approach can be applied in a fisheries management context when information needed to inform regulations is unavailable, yet conservation concerns exist. Our research uses a translational ecology framework to assess the stock status and develop research priorities for the crevalle jack (Caranx hippos) in the Florida Keys, USA, a currently unregulated species. Interview data that compiled expert fishing guide knowledge were used to develop hypotheses tested using existing fisheries-dependent datasets to check for agreement among sources and assess the consistency of observed patterns. Six hypotheses were developed concerning the status and trends of the crevalle jack population in the Florida Keys, and four of these hypotheses received clear support, with agreement between guide observations and one or more of the fisheries-dependent datasets. The results of our study outline an effective translational ecology approach for recreational fisheries management designed to rapidly recognize potential management needs as identified by fishing guides, which allows for actionable science and proactive management.

Automatic segmentation of fish midlines for optimizing robot design

While fish use continuous and flexible bodies to propel themselves, fish robots are often made from interconnected segments. How many segments do robots need to represent fish movements accurately? We propose a new method to automatically determine parsimonious robot models from actual fish data. We first identify key bending points (i.e., joint positions) along the body and then study the concerted movement of the segments so that the difference between actual fish and modelled bending kinematics is minimized. To demonstrate the utility of our method, we analyse the steady swimming kinematics of 10 morphologically distinct fish species. Broadly classified as sub-carangiform (e.g., rainbow trout) and carangiform (e.g., crevalle jack) swimmers, these species exhibit variations in the way they undulate when traditional parameters (including head and tail beat amplitudes, body wavelength and maximum curvature along the body) are considered. We show that five segments are sufficient to describe the kinematics with at least 99% accuracy. For optimal performance, segments should progressively get shorter towards the tail. We also show that locations where bending moments are applied vary among species, possibly because of differences in morphology. More specifically, we find that wider fish have shorter head segments. We discover that once bending points are factored in, the kinematics differences observed in these species collapse into a single undulatory pattern. The amplitude and timing of how body segments move entirely depend on their respective joint positions along the body. Head and body segments are also coupled in a timely manner, which depends on the position of the most anterior joint. Our findings provide a mechanistic understanding of how morphology relates to kinematics and highlight the importance of head control, which is often overlooked in current robot designs.

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

Species composition, abundance and diversity of beach seine catches at Sakumono landing beach, Ghana

Fisherman at the Sakumono landing beach, Ghana are constantly experiencing high rate of marine litter in their catches which is currently having negative effect on the composition and abundance of species within the nearshore environment. Given this, the main objective of the study was to assess the diversity and composition of catches from beach seine fishermen in Sakumono landing beach, Ghana. Samples of fish were purchased from beach seine fishermen from the nearshore waters at Sakumono near Accra (Ghana) from September, 2018 to August, 2019. From the samples, species abundance and composition were assessed. The species diversity indices including richness, evenness, dominance and diversity indices were calculated using PAST statistical tool. A total of 28 species belonging to 18 families was recorded. The dominant taxonomic families were: Carangidae and Sciaenidae. The dominant species from the study was Pteroscion peli as the most dominant (27%) while Caranx hippos, Dasyatis margarita, Trachinotus goreensis, Penaeus notialis and Sardinella aurita were the least dominant species (less than 0.1%). The species richness using Margalef index ranged from 1.14 to 2.75. The range for species evenness estimated using Pielou’s index was 0.32 - 0.67. The dominance index was estimated as 0.53 - 0.71. The range of the Shannon index was less than 3.0 which indicated that the Sakumono nearshore waters of Ghana is moderately polluted.

TWO Caranx caninus (CARANGIDAE, PERCIFORMES) SPECIMENS WITH PUG-HEADED, EXOPHTHALMOS, OPERCLE, AND ANAL FIN ABNORMALITIES; FIRST RECORD FOR THE EASTERN PACIFIC

The Pacific crevalle jack, Caranx caninus Günther, 1867, is a marine pelagic migratory fish species that usually inhabit shallow coastal water, including brackish and estuarine areas. The “pug-headed” abnormality in teleost fishes is characterized by an abnormal skeletal formation of the head, affected by an anteroposterior compression of the upper jaw, resulting in an abnormally shorter upper jaw concerning its lower jaw. In October 2016, an artisanal fisherman from Puerto Chale (Eastern Pacific, Mexico) captured a shoal of Pacific crevalle jack, where two of them presented morphological anomalies of pug-head, exophthalmos, opercle and anal fin. Both specimens’ size and weight were 69.9 and 59.3 cm fork length and 3200 and 2550 g, respectively. One of the individuals was a six-year-old female. A list of 58 cases of pug-headed marine fishes worldwide is provided and reviewed in this article. This study is the first report for the Eastern Pacific and also for wild specimens of Carangidae species. The causes of this abnormality remain uncertain and the main hypotheses were reviewed in this study. However, factors such as temperature, nutrition, salinity, oxygen dissolved, pressure, unspecified pollutants are not discarded. More studies in the future, including new techniques, must be done to clarify the causes of this abnormality.

Modal decompositions of the kinematics of Crevalle jack and the fluid–caudal fin interaction

To understand the governing mechanisms of bio-inspired swimming has always been challenging due to intense interactions between flexible bodies of natural aquatic species and water around them. Advanced modal decomposition techniques provide us with tools to develop more in-depth understating about these complex dynamical systems. In this paper, we employ proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD) techniques to extract energetically strongest spatio-temporal orthonormal components of complex kinematics of a Crevalle jack (Caranx hippos) fish. Then, we present a computational framework for handling fluid–structure interaction related problems in order to investigate their contributions towards the overall dynamics of highly nonlinear systems. We find that the undulating motion of this fish can be described by only two standing-wave like spatially orthonormal modes. Constructing the data set from our numerical simulations for flows over the membranous caudal fin of the jack fish, our modal analyses reveal that only the first few modes receive energy from both the fluid and structure, but the contribution of the structure in the remaining modes is minimal. For the viscous and transitional flow conditions considered here, both spatially and temporally orthonormal modes show strikingly similar coherent flow structures. Our investigations are expected to assist in developing data-driven reduced-order mathematical models to examine the dynamics of bio-inspired swimming robots and develop new and effective control strategies to bring their performance closer to real fish species.

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

Simple SummaryParasitic isopods were reported found from marine fishes from many habitat in the world. In Thailand, there is not much study on this parasitic group. This work has compiled all published parasitic isopods documents in Thailand from year 1950 to present include collecting samples from the Gulf of Thailand during the period 2006–2019. New host records were found from four species of parasitic isopods (Cymothoa eremita, Smenispa irregularis, Nerocila sundaica, Norileca triangulata) and two species of parasitic isopods (Argathona macronema, Norileca triangulata) were found first time in the central Indo-Pacific region.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.

Environmental and Structural Drivers of Fish Distributions among Petroleum Platforms across the U.S. Gulf of Mexico

AbstractPetroleum platforms in the U.S. Gulf of Mexico (GOM) are important habitats for fishes and support regional fisheries. However, drivers of the horizontal (i.e., latitudinal and longitudinal) and vertical (i.e., position in the water column) distribution patterns of fishes associated with these artificial habitats are not fully understood on a GOM‐wide scale. To build upon previous studies on a large spatial scale and focus on species‐specific drivers, we conducted 114 submersible rotating drop‐camera and water quality sonde surveys at 54 platforms throughout the GOM. We then fitted two sets of binomial generalized additive mixed models integrating environmental and structural (i.e., characteristics of platforms) predictors to encounter/nonencounter data for 17 fish species so as to understand their horizontal and vertical distribution patterns throughout the GOM in platform habitat. Significant predictors for horizontal distribution included distance from shore (for Bermuda Chub Kyphosus saltatrix, Greater Amberjack Seriola dumerili, Vermilion Snapper Rhomboplites aurorubens), salinity (Bermuda Chub, Red Snapper Lutjanus campechanus), the number of platforms within 5 km (Blue Runner Caranx crysos, Crevalle Jack Caranx hippos), and dissolved oxygen concentration (Red Snapper). Significant predictors for vertical distribution included temperature (for Atlantic Spadefish Chaetodipterus faber, Bermuda Chub, Blue Runner, Greater Amberjack, Red Snapper), salinity (Greater Amberjack, Red Snapper), dissolved oxygen concentration (Red Snapper), and seafloor depth (Red Snapper). However, the majority of the study species were not influenced by the predictors included in the horizontal (11 of 17 species) and vertical distribution (12 of 17 species) generalized additive mixed models. Thus, many GOM fishes were found to associate with platforms over a relatively wide range of environmental conditions and platform characteristics. This suggests specific environmental conditions and distinct platform characteristics may not be as important as the simple number of available platforms for determining the distributions of many platform‐associated fishes in the GOM.

Condition factor, heavy metals and polychlorinated biphenyls (PCBs) in the muscle of fishes harvested in, and imported into Lagos, Nigeria

Fish is an important part of the human diet, are at the top of the aquatic food chain with a high propensity to accumulating contaminants like heavy metals and polychlorinated biphenyls (PCBs) which are toxic to humans. The objective of this study was to evaluate the relationship between condition factor (physiologic wellbeing) of the fishes, PCBs, and heavy metal accumulation.Ten adult fish species three each of Chrysichthys nigrodigitatus, Trachinotus teraia, Liza dumerilli, Tilapia guieensis, Pseudotolithus elongatus, Pomadasys jubelini, Polydactylus quadrifilis, Caranx hippos, Sphyreana barracuda, Arius heudoloti,were acquired at Epe Lagoon. Ten adult fish species three each of Argentina silus, Gadus chalcogrammus, Gadus morhua, Atlantic mackerel, Micropogonias undulatus, Urophycis sp., Chrysichthys nigrodigitatus, Oreochromis niloticus, Clupea harengus, Trachurus trachurus, imported into Lagos were purchased. The fish species’ condition factor was determined. The heavy metals were determined using AAS while PCB level was determined using GC-MS. Iron, mercury, zinc, arsenic, nickel and copper levels correlated positively with the condition factor in the local fishes while in the imported fishes, cadmium, iron, zinc, nickel, copper and lead levels correlated positively to the condition factor. The levels of PCBs in both the local and imported fishes were non-detectable. It is concluded that the lead, copper, arsenic, zinc, mercury and cadmium in both the imported and local fishes were within permissible limits compared with the FAO/WHO maximum permissible limits. The positive correlation of some heavy metals to the fishes’ condition factor infers that these metals might be altering physiologic activities in the fishes. Keywords: Condition factor; Heavy metals; Polychlorinated biphenyl; Fish