Istiophorus Platypterus Research Articles

Assessing illegal fishing and trade of Atlantic billfish and swordfish by DNA-based identification

Due to the morphological similarity between some billfish species, the International Commission for the Conservation of Atlantic Tunas (ICCAT) recommends the use of molecular tools to identify billfish at the species level to properly manage this imperiled group. In this study, species-specific swordfish and billfish identification was carried out by using PCR-RFLP and multiplex PCR of the mitochondrial COI gene. Samples were obtained during landings of the tuna fleet at the Public Fisheries Port of Santos (PFPS) and in the General Warehouse Company of Sao Paulo (CEAGESP), Brazil. A total of 87 samples from PFPS were identified: Kajikia albida, Tetrapturus georgii, T. pfluegeri, Makaira nigricans, and Istiophorus platypterus. At CEAGESP, 432 individuals were collected, and three species were detected: Xiphias gladius, I. platypterus and T. georgii. Some samples presented an unknown band pattern for PCR-RFLP, which were sequenced and identified as X. gladius. These findings demonstrate that billfishes protected by law are being caught by industrial fisheries, but they are not traded at the CEAGESP. We advocate continuous onboard and of landings fishing monitoring using molecular identification tools in accordance with ICCAT recommendations. We provided evidence that DNA-based methods are efficient in overcoming billfish misidentification in the Atlantic Ocean.

Arsenic in the top predators sailfish (Istiophorus platypterus) and dolphinfish (Coryphaena hippurus) off the southeastern Gulf of California.

Distribution of arsenic (As) in tissues and gonads of the Indo-Pacific sailfish Istiophorus platypterus and the dolphinfish Coryphaena hippurus from the SE Gulf of California was evaluated. The bioaccumulation patterns of As were the same in the two species. In I. platypterus, As levels (mg kg-1, wet weight) were gonads (7.4 ± 1.1) > liver (3.1 ± 0.1) > kidney (2.7 ± 0.1) > muscle (1.6 ± 0.1); in C. hippurus, As (mg kg-1) levels were gonads (4.3 ± 0.6) > liver (3.2 ± 0.2) > kidney (2.3 ± 0.1) > muscle (1.2 ± 0.1). Differences in As distribution could be attributed to the biological functions of tissues. The hypothesis was confirmed that biomagnification was evidenced by the fact that As levels were lower in prey species than in predators. Intake of muscle from either fish did not represent a risk to humans if recommended portions a week are not exceeded, adults as much as 1802.4g and 2454.1g and children 257.5 and 350.6g, for sailfish and dolphinfish, respectively. In addition, the likelihood of developing cancer due to consumption of edible tissues from either of these top predators was in the acceptable range (6.4 × 10-5 to 27.3 × 10-6 for a population that consumes 50g of muscle in a week) but if a conservative combined slope factor is used the probabilities to develop bladder and lung cancer increments from 1.1 × 10-3 to 9.1 × 10-5.

Molecular cytogenetics insights in two pelagic big-game fishes in the Atlantic, the tarpon, Megalops atlanticus (Elopiformes: Megalopidae), and the sailfish, Istiophorus platypterus (Istiophoriformes: Istiophoridae)

Abstract Some pelagic and usually large sized fishes are preferential targets for sport and commercial fishing. Despite their economic importance, cytogenetic data on their evolutionary processes and management are very deficient, especially due to logistical difficulties. Here, information for two of such charismatic species, the tarpon, Megalops atlanticus (Elopiformes: Megalopidae), and the sailfish, Istiophorus platypterus (Istiophoriformes: Istiophoridae), both with a wide Atlantic distribution, were provided. Cytogenetic data were obtained using conventional methods (Giemsa staining, Ag-NORs technique, and C-banding), base-specific fluorochrome staining and fluorescence in situ hybridization (FISH) with rDNA probes. Megalops atlanticus has 2n = 50 chromosomes, all acrocentric ones (NF = 50), while Istiophorus platypterus has 2n = 48 chromosomes, 2m + 2st + 44a (NF = 52). Megalops atlanticus populations from the South Atlantic and Caribbean share identical karyotypic patterns, likely associated with gene flow between them. In turn, I. platypterus presents karyotype similarities with phylogenetically close groups, such as Carangidae. The chromosomal characteristics of these species highlight their independent evolutionary paths. Additionally, the current data contribute to knowledge of new aspects of pelagic fish fauna and will support further comparative studies with congeneric species, clarifying evolutionary karyotype trends of these fish groups.

Biología reproductiva del pez vela Istiophorus platypterus en la Bahía de Acapulco, Méxic

Background. The sailfish Istiophorus platypterus is a viviparous billfish species, it is caught by trolling in the sports fishery in Mexico. However, to date, there has been no reproductive biology studies of sailfish in Acapulco Bay, although the reproductive aspects of any species represent essential information for the design of management plans. Goals. Estimate the spawning frequency and batch fecundity to quantify reproductive characteristics of sailfish in waters off Acapulco, Bay. Methods. During the period 2008–2019, a total of 581 fish were sampled. Macroscopy analysis and quantitative histology was used to describe reproductive characteristics of the sailfish gonads. Results. 55.8% of the organisms analyzed were males, the remaining 44.2% were females, the sex ratio (1.26 M: 1 H) was different from the expected theoretical ratio (X2 = 7.53). The ovaries of 155 females were classified into five ovarian development phases based on histological analysis of the most advanced group of oocytes. Sailfish are multiple spawners with asynchronous oocyte development. Batch fecundity for 14 females with the presence of hydrated oocytes but without postovulatory follicles ranged 0.330 to 2.092 × 106 eggs with an average of 1.07 × 106 eggs. Gonadosomatic indices (GSI) indicated that sailfish have a reproductive period with peaks in August and October (mean monthly GSI= 4.3% and 5.4%). Conclusions. Population sailfish in Acapulco Bay is composed of males and females in similar proportions, with a gonadal development by groups that can be described in five development phases, a reproductive maximum during the warm months of the year and a relatively high fecundity.

Biología reproductiva del pez vela Istiophorus platypterus en la Bahía de Acapulco, Méxic

Biología reproductiva del pez vela Istiophorus platypterus en la Bahía de Acapulco, Méxic

Nuevos registros de peces para el área marina del Parque Nacional Sistema Arrecifal Veracruzano, suroeste del Golfo de México

Presentamos cinco nuevos registros de peces para el área marina del Parque Nacional Sistema Arrecifal Veracruzano, con evidencia fotográfica y se proveen los datos morfométricos y merísticos básicos: el miraestrellas Gillellus greyae (70.3 mm, Longitud total), el góbido Oxyurichthys stigmalophius (36 mm, Longitud total), el cochito manchado Canthidermis maculata (342.4 mm, Longitud total) y el pez vela Istiophorus platypterus (?1,800 mm, Longitud total) se distribuyen ampliamente en el Caribe; además del primer registro en el Golfo de México del lenguado manchado Bothus maculiferus (250 mm, Longitud total).

Next-generation sequencing yields the complete mitochondrial genome of the Capsala pricei Hidalgo, 1959 (Platyhelminthes: Monogenea) from South China Sea

The complete mitochondrial genome of the Capsala pricei (Monogenea: Capsalidae) collected from the sailfish (Istiophorus platypterus) was sequenced by the next-generation sequencing method. The mitogenome is 13,851 bp in length, includes 12 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and a control region, with the atp8 gene being absent. The overall content of A + T is 69.26%, which is significantly higher than the C + G content (30.74%). C shows the lowest frequency (13.42%) among four bases. Phylogeography analysis showed a close relationship between the genus Capsala and Neobenedenia with high bootstrap value supported.

Incorporating depth into habitat use descriptions for sailfish Istiophorus platypterus and habitat overlap with other billfishes in the western North Atlantic

The sailfish Istiophorus platypterus is a circumglobal billfish species. It is commonly targeted in recreational fisheries and caught as by-catch in commercial fisheries, and therefore fisheries management would benefit from an enhanced understanding of basic patterns of the species’ daily and seasonal movements. Between 2002 and 2007, 87 billfish were tagged with pop-off satellite archival tags in the Atlantic waters off the coast of South Carolina, USA, including sailfish (n = 54), blue marlin Makaira nigricans (n = 15), and white marlin Kajikia albida (n = 18). Only fish meeting specific tag program criteria and length of tag attachment were selected for further analysis (sailfish, n = 19; blue marlin, n = 4; white marlin, n = 3). Differential horizontal and vertical movement patterns were observed within sailfish by season. Two- and three-dimensional (3D) analyses showed differential spatial niche use by sailfish. Among the istiophorid species, 3D analysis showed less overlap when occupying similar horizontal areas. The results from this study, in conjunction with similar studies from other areas, provide a better understanding of habitat usage that can be applied to address uncertainties in ecology or management, such as characterization of stock structure, identifying potential spawning habitat or intra-specific competition, providing correction factors for indices of abundance, and characterizing vulnerability to fishing gear.

Occurrence of microplastics in epipelagic and mesopelagic fishes from Tuticorin, Southeast coast of India

This study investigated the microplastic (MP) contamination of seawater and fishes from different habitats so as to understand the level of human exposure to microplastics. Samples of Harpodon nehereus, Chirocentrus dorab, Sardinella albella, Rastrelliger kanagurta, Katsuwonus pelamis and Istiophorus platypterus were collected from Tuticorin, southeast coast of India. The MPs in seawater and the gastrointestinal tracts of fish were identified using Stereomicroscope and characterized by FTIR and SEM-EDAX analysis. The abundance of MPs varied from 3.1 ± 2.3 to 23.7 ± 4.2 items L−1 in water, from 0.11 ± 0.06 to 3.64 ± 1.7 items/individual, and from 0.0002 ± 0.0001 to 0.2 ± 0.03 items/g gut weight. The epipelagic fishes had higher levels of MP contamination than the mesopelagic ones. Most of the MPs identified were of blue color, of fiber type and with their size <500 μm. Polyethylene was the most commonly detected MP, followed by polyester and polyamide, and this fact could be attributed to the inflow of domestic sewage and to the intensive fisheries activities in the area. SEM-EDAX spectra revealed the weathered MP surfaces which could adsorb/leach inorganic elements (colorants and fillers) from/to the environment. We may conclude that the concentration of MPs in fishes is a function of the concentration of MPs in their environment.

Use of genetic markers to identify the illegal trade of billfish in the second largest fishing warehouse of Latin America

Abstract Billfish are oceanic pelagic species that are often caught by tuna fleets and are of great interest for sport fishing. Two species of billfish have specific legislation prohibiting their marketing and export in Brazil. DNA barcoding is a universal system of molecular identification based on a sequence of mitochondrial DNA cytochrome oxidase subunit I (COI), which serves as a diagnostic genomic marker in each species. The barcode DNA technique was used to identify billfish marketed in the second largest fishing warehouse in Latin America, the CEAGESP (Companhia de Entrepostos e Armazéns Gerais de São Paulo), located in São Paulo, Brazil. Seventy‐nine samples of billfish were collected during three inspection visits carried out by Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis. After DNA sequencing, 70 samples (88.60%) were identified to the species level; 21 (30.00%) were identified as Xiphias gladius, 43 (61.42%) as Istiophorus platypterus and six (8.57%) as Kajikia albida. The sale of this latter species is prohibited in Brazil and it is considered Vulnerable on the list of endangered species of the IUCN and in the official list of species of endangered Fauna – Fish and Aquatic Invertebrates. Molecular analyses proved to be very efficient at uncovering irregularities in the identification of the white marlin (K. albida), which was traded illegally in CEAGESP, demonstrating the ineffectiveness of the current monitoring techniques used and emphasizing the need for the adoption of better public policies for the conservation of the species.

Linking hunting weaponry to attack strategies in sailfish and striped marlin.

Linking morphological differences in foraging adaptations to prey choice and feeding strategies has provided major evolutionary insights across taxa. Here, we combine behavioural and morphological approaches to explore and compare the role of the rostrum (bill) and micro-teeth in the feeding behaviour of sailfish (Istiophorus platypterus) and striped marlin (Kajikia audax) when attacking schooling sardine prey. Behavioural results from high-speed videos showed that sailfish and striped marlin both regularly made rostrum contact with prey but displayed distinct strategies. Marlin used high-speed dashes, breaking schools apart, often contacting prey incidentally or tapping at isolated prey with their rostra; while sailfish used their rostra more frequently and tended to use a slower, less disruptive approach with more horizontal rostral slashes on cohesive prey schools. Capture success per attack was similar between species, but striped marlin had higher capture rates per minute. The rostra of both species are covered with micro-teeth, and micro-CT imaging showed that species did not differ in average micro-tooth length, but sailfish had a higher density of micro-teeth on the dorsal and ventral sides of their rostra and a higher amount of micro-teeth regrowth, suggesting a greater amount of rostrum use is associated with more investment in micro-teeth. Our analysis shows that the rostra of billfish are used in distinct ways and we discuss our results in the broader context of relationships between morphological and behavioural feeding adaptations across species.

Oil gland and oil pores in billfishes: in search of a function.

Billfishes are well known for their distinctive elongated rostra, i.e. bills. The functional significance of billfish rostra has been frequently discussed and the recent discovery of an oil gland (glandula oleofera) at the base of the rostrum in swordfish, Xiphias gladius, has added an interesting facet to this discussion regarding the potential co-evolution of gland and rostra. Here, we investigated the oil gland and oil pores (through which the oil is brought to the skin surface) of four billfish species - swordfish, Atlantic blue marlin (Makaira nigricans), Indo-Pacific sailfish (Istiophorus platypterus) and striped marlin (Kajikia audax) - and provide detailed evidence for the presence of an oil gland in the last three. All four species had a high density of oil pores on the forehead which is consistent with the hypothesis of hydrodynamic benefits of the oil. The extension of the pores onto the front half of the rostrum in sailfish and striped marlin, but not in swordfish or blue marlin, suggests that the oil may have additional functions. One such function could be linked to the antibacterial and anti-inflammatory properties of the oil. However, the available evidence on predatory rostrum use (and hence the likelihood of tissue damage) is only partly consistent with the extension of pores on rostra across species. We conclude that the oil gland probably serves multiple, non-mutually exclusive functions. More detailed information on rostrum use in blue marlin and swordfish is needed to better link behavioural and morphological data with the aim of accomplishing a full comparative analysis.

A Standardized Abundance Index from Fishery Independent Data: A Case Study of Swordfish (Xiphias Gladius) from Indonesian Tuna Longline Fishery

Most varieties of the billfish caught in the Indian Ocean are either swordfish or Indo-Pacific sailfish. Swordfish is mostly considered as by-catch from tuna longline fisheries, except for South African, Spanish and Portuguese fleets. Despite of its importance, little are known about their abundance. Relative abundance indices are the input data for stock assessment analyses that provide useful information for decision making and fishery management. In this paper, a Generalized Linear Model (GLM) was utilized to systematize the catch-per-unit-effort (CPUE) and to estimate relative abundance indices based on the Indonesian longline dataset. The data was collected by scientific observers from August 2005 to December 2016. Conventional models for counting data were used, but zero-inflated and hurdle models also considered, due to the high number of zero-catchper-set. Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC) were applied to select the best models among all those evaluated. Both AIC and BIC suggested that the simple negative binomial (NB) model is the best option. The trends were relatively similar to the nominal series, but with smoother peaks. In general, there was a tendency of positive trends in the last decade, with the series varying throughout the period.

Mercury contents in commercial Billfish species of the Western Central Atlantic: Assessing the potential risks to human health of Billfish consumption

Purpose of the present study was to evaluate the total Hg (THg) level in Billfish caught in the Western Central Atlantic and to assess the potential health consequences due to consumption for people living in Grenada (GR) and in the Dominican Republic (DR). Consumption data were collected through the administration of an online questionnaire and THg was measured in samples of Atlantic sailfish (Istiophorus platypterus, n = 38), Blue Marlin (Makaira nigricans, n = 62) and White marlin (Kajikia albida, n = 45) collected at the main fish landing point in GR and in DR. The potential health risk for different consumer groups was evaluated by calculating the estimated metal weekly intake rate (MWIR; μg kg−1 body weight), that was compared to the provisional tolerable weekly intake (PTWI) for methylmercury (MeHg), and the total hazard quotient (THQ). A conservative approach was applied considering that THg was detected in its more toxic form, i.e. MeHg. The following levels of THg values were detected: Blue Marlin (0.09–6.23 mg kg−1), White Marlin (0.05–3.21 mg kg−1) and Atlantic sailfish (0.03–0.64 mg kg−1). For average consumers, the estimated MWIR minimally contributed to the PTWI and the THQ values turned out to be far below 1 in both the studied countries. Differently, the results regarding high consumers (95 percentile) raised some concerns.

Identifying the species of harvested tuna and billfish using deep convolutional neural networks

AbstractFish catch species provide essential information for marine resource management. Some international organizations demand fishing vessels to report the species statistics of fish catch. Conventionally, the statistics are recorded manually by observers or fishermen. The accuracy of these statistics is, however, questionable due to the possibility of underreporting or misreporting. This paper proposes to automatically identify the species of common tuna and billfish using machine vision. The species include albacore (Thunnus alalunga), bigeye tuna (Thunnus obesus), yellowfin tuna (Thunnus albacares), blue marlin (Makaira nigricans), Indo-pacific sailfish (Istiophorus platypterus), and swordfish (Xiphias gladius). In this approach, the images of fish catch are acquired on the decks of fishing vessels. Deep convolutional neural network models are then developed to identify the species from the images. The proposed approach achieves an accuracy of at least 96.24%.

ĐÁNH GIÁ RỦI RO SINH THÁI CỦA NGHỀ KHAI THÁC CÁ NGỪ ĐẠI DƯƠNG Ở BIỂN VIỆT NAM ĐỐI VỚI CÁC LOÀI KHAI THÁC THỨ CẤP

Ecological risk assessments of the oceanic tuna fisheries on the secondary species in the Sea of Vietnam were conducted following the productivity and susceptibility analysis (PSA) method suggested by Marine Stewardship Council. The secondary species were identified through compilation and analysis of data collected in 67 observer trips conducted on board of commercial tuna fisheries by Research Institute for Marine Fisheries (RIMF) and WWF-Vietnam during the period 2000-2016. The consequence analysis pointed out that there were 12 secondary species of tuna fisheries which were taken into PSA analysis. The results indicated that most of species were at medium and low risk level. Species considered at medium risk are Pelagic thresher (Alopias pelagicus), Blue shark (Prionace glauca), Scalloped hammerhead (Sphyrna lewini), Wahoo (Acanthocybium solandri), Escolar (Lepidocybium flavobrunneum), Indo-Pacific sailfish (Istiophorus platypterus) and at low risk are Longtail tuna (Thunnus tonggol), Swordfish (Xiphias gladius), Snake mackerel (Gempylus serpens), Black marlin (Makaira indica), Indo-Pacific blue marlin (M. mazara) and Common dolphinfish (Coryphaena hippurus). Yellowfin Tuna (Thunnus albacares) and Bigeye Tuna (T. obesus) are target species and both at ecologically low risk level. The results also showed that tuna handline fishery has less impacts on group of secondary species compared to longline fishery.

The use of portable fish aggregating devices for pelagic fish in Sunda Strait Water, Indonesia

Portable FADs is a transformation of the conventional FADs which uses the concept of fish responses related to the use of sound frequencies. Portable FADs is a new innovation auxiliary gear in pelagic fishing. The aims of this study are to know the prototype of portable FAD, to know dominant fish compositions of the catches around portable FADs and to analyze total buoyant and sinking force of portable FADs. The study was conducted in laboratory and field experiment in Sunda strait waters. Data analysis were performed by using buoyancy force and sinking force analysis of portable FADs and the composition of the catch. The prototype of portable FADs was made from fiber with dimensions L x W x H = 63 x 43 x 25 cm. The composition of the dominant fish around portable FADs are 83 tails of Rastrelliger sp., 57 tails of Istiophorus platypterus and 51 tails of Euthynnus affinis. Portable FAD has total buoyancy and sinking force of portable FADs are 192.888,2 GS and GS 179.538,19.

Description of buoyant fibers adhering to Argonauta nouryi (Cephalopoda: Argonautidae) collected from the stomach contents of three top predators in the Mexican South Pacific

Argonauta nouryi Lorois, 1852 is an octopod that inhabits the holopelagic zone, the objective of this study was to describe the occurrence of buoyant fibers adhering to the body and mantle cavity of A. nouryi females found in the stomach contents from Euthynnus lineatus (skipjack), Coryphaena hippurus (dolphinfish), and Istiophorus platypterus (sailfish). Stomach contents from 224 individuals were examined. All female evaluated presented fibers adhering to the mantle cavity; 92.6% of the fibers measured 0.25 to 5 mm in length and hyaline was the dominant color (72%). The amount of fibers in the fish stomach contents with A. nouryi was significantly greater than in stomachs without; this suggests that the fibers might be introduced via A. nouryi. Findings of this work could be related to the discharge of solid materials in the water column.

Isolation and characterization of 21 novel microsatellite loci in sailfish Istiophorus platypterus Shaw 1792 from a shotgun genomic library

Secretaria de Investigacion y Posgrado-Instituto Politecnico Nacional [SIP-20161472]; Consejo Nacional de Ciencia y Tecnologia (CONACYT) of Mexico [60376]

Length weight relationships of top predator fish caught by the sport fishing fleet off Cabo San Lucas, Baja California Sur, Mexico

Length-weight relationships (LWRs) were estimated for Pacific blue marlin ( Makaira nigricans ), striped marlin ( Kajikia audax ), sailfish ( Istiophorus platypterus ), dolphinfish ( Coryphaena hippurus ) and yellowfin tuna ( Thunnus albacares ). These five fish species are key top predators of the pelagic ecosystem and are economically important resources in the sport fishing of Baja California Sur, Mexico. Overall, 53,359 length and weight records were analyzed for the period 1990-2015. LWRs were significant ( P < 0.05), with b -values ranging from 2.52 to 3.13.