Eagle Ray Research Articles

A revised generic arrangement for the eagle ray family Myliobatidae, with definitions for the valid genera.

The generic arrangement of the eagle rays (Family Myliobatidae) is revised and the genus Pteromylaeus Garman, 1913 is placed into the synonymy of Aetomylaeus Garman, 1908. Definitions are provided for the three valid genera, Aetobatus, Aetomylaeus and Myliobatis, and nomenclatural issues are discussed. Aetobatus differs from the latter two genera in having: a deeply notched nasal curtain, both jaws with a single row of chevron-shaped teeth, broadly rounded pectoral-fin free rear tips, pectoral fins separate from rostral lobe and joining head at level of eye. Aetomylaeus differs from the other two genera in having: pectoral fins separate from rostral lobe and joining head below level of eye, and stinging spine absent or present (usually not well developed when present). Myliobatis differs from the other two genera in having the pectoral fins joined to the rostral lobe by a subocular ridge. A list of valid species is provided, including a list of junior synonyms. Myliobatis australis Macleay, 1881 from southern Australia is placed into the synonymy of the previously considered endemic New Zealand species, M.tenuicaudatus Hector, 1877.

Life history and seasonal occurrence of the spotted eagle ray, Aetobatus narinari, in the eastern Gulf of Mexico

The spotted eagle ray, Aetobatus narinari, is listed on the IUCN Red List of Threatened Species as Near Threatened with a decreasing population trend, but many aspects of this ray’s biology and population status are unknown. Aerial and on-water surveys were conducted in the eastern Gulf of Mexico off southwest Florida 2008–2013, to document seasonal occurrence and life history characteristics of this species. Aerial surveys documented spotted eagle rays mostly in spring, summer, and autumn months with larger aggregations observed near inlet passes. Boat-based surveys documented rays on 152 out of 176 survey days, mostly as solitary individuals but sometimes in aggregations of up to 60. More rays were observed when water temperatures were 23-31 oC. A total of 393 rays (231 males, 161 females, 1 unrecorded sex) were captured, measured, sampled, tagged, and released. Sizes ranged 41.4–203.0 cm disc width (DW) and weight 1.1–105.5 kg. Male size at 50 % maturity was 127 cm DW. Five percent (19) of tagged rays were recaptured after 5–1,293 days at liberty and recaptured rays exhibited faster growth than previously estimated from vertebral readings. Based on observations of rays relative to survey effort, numbers of observed rays declined after 2009 for reasons not yet understood. This observation, together with concerns about sustainability of fisheries targeting these rays in nearby Mexico and Cuba, underscore the need for investigations into stock structure, population trends, growth, and critical habitat of spotted eagle rays throughout the Gulf of Mexico, Caribbean Sea, and elsewhere in their range.

Towed-float satellite telemetry tracks large-scale movement and habitat connectivity of myliobatid stingrays

Batoids are important mesopredators whose high mobility and extensive migrations can link seemingly distant food webs in coastal ecosystems. Despite this recognition, our knowledge of the movement patterns of many species is limited due to the logistical challenge of tracking these animals on multiple scales. Smart Positioning or Temperature (SPOT) satellite-linked transmitters allow for precise, multi-scale tracking of species that regularly use surface waters. To date, SPOTs have been predominantly used on sharks, with only a single application to a batoid. Given the epipelagic nature of myliobatid stingrays, we examined the potential for towed-float SPOT transmitters to monitor large-scale movements of two representative species: the Cownose Ray (Rhinoptera bonasus; n = 15) and Spotted Eagle Ray (Aetobatus narinari; n = 9). Tracking data identified several consistent outmigration patterns of Cownose Rays along the Mississippi-Alabama shelf and seasonal variation in movement rates along barrier island habitats. We also documented sex-related differences in movement rates and habitat use of Spotted Eagle Rays along the Bermuda platform, where males exhibited significantly higher movement rates than females and more transient behavior between inshore lagoons and outer coral reefs. Both Cownose and Spotted Eagle Rays were shown to exhibit connectivity among several habitat types along continental shelves in their respective locales, demonstrating future challenges to the management of these species over large spatial scales. While reductions in tag size and improved tethering techniques would undoubtedly broaden the applicability of towed-float satellite telemetry to other species and sizes, our work highlights the strong potential for this technology to provide insights into the spatial ecology and habitat use of myliobatid rays.

Kin structure and social organization in the spotted eagle ray, Aetobatus narinari, off coastal Sarasota, FL

Observations of elasmobranchs in groups suggest sociality in sharks and rays. However we currently lack a strong understanding of social structure and the role kinship has in structuring group organization in cartilaginous fishes. The spotted eagle ray, Aetobatus narinari (Euphrasen, 1790) frequents the shallow waters near Sarasota, FL, often in pairs or groups suggesting a social component to their behavior. In the present study, eight eagle ray-specific microsatellite markers were used to investigate relatedness in A. narinari groups, and used to determine if kin structure contributed to group organization. Using regression-based and maximum-likelihood approaches, relatedness was quantified and compared within and among groups of juveniles, and adults in mixed sex and same sex groups. Results showed a lack of kin-structured sociality in A. narinari, suggesting factors apart from relatedness shape social interactions among spotted eagle rays in the near-shore waters of Sarasota, FL. Our results add to the limited amount of published literature on elasmobranch kinship, which are important for understanding implications of anthropogenic disturbance on genetic variability for coastal populations.

Seussapex, a new genus of lecanicephalidean tapeworm (Platyhelminthes: Cestoda) from the stingray genus Himantura (Myliobatiformes: Dasyatidae) in the Indo-West Pacific with investigation of mode of attachment.

A new lecanicephalidean genus, Seussapex gen. n., is erected for specimens collected from stingrays from the Indo-West Pacific resembling the little known species Tenia [sic] narinari MacCallum, 1917 from the spotted eagle ray, Aetobatus narinari (Euphrasen). Members of this new genus are unique in their possession of a multi-tiered apical structure comprising a bipartite apical modification of the scolex proper, and an externally bipartite apical organ with anterior and posterior glandular compartments internally. The appearance of the scolex varies dramatically depending on state of protrusion and/or evagination of these different parts which appear to be able to function independently. Seussapex karybares sp. n. parasitizing Himantura uarnak 2 (sensu Naylor et al., 2012) in northern Australia is described as the type species and Tenia [sic] narinari is transferred to the new genus. The two species differ in scolex length and width of the posterior dome-shaped portion of the apical organ. Histological sections of scoleces stained using the periodic acid-Schiff(PAS) reaction showed the surface of the anterior part of the apical organ and the anterior glandular compartment to stain PAS positive, suggesting a chemical mode of attachment to the host's intestinal mucosal surface. Extensive collecting efforts of stingrays in the Indo-West Pacific shows Seussapex gen. n. to be restricted to species of Himantura Miller et Henle and suggests additional diversity in this group of hosts. In addition, the host identity of Seussapex narinari (MacCallum, 1917) comb. n. is called into question.

The Ocellated Eagle Ray,Aetobatus ocellatus(Myliobatiformes: Myliobatidae), from Borneo and Northern Australia as Host of Four New Species ofHornellobothrium(Cestoda: Lecanicephalidea)

Four new species are described in the lecanicephalidean genus Hornellobothrium from the ocellated eagle ray, Aetobatus ocellatus, from Australia and Indonesian Borneo. The species possess flat, laterally expanded immature proglottids and a small internal, glandular apical organ diagnostic of the genus. To date, only 2 valid species are recognized in the genus: Hornellobothrium cobraformis Shipley & Hornell, 1906 , from " Aetobatus narinari " from Sri Lanka, and Hornellobothrium extensivum Jensen, 2005 , from A. ocellatus , also from Australia. The new species differ from H. cobraformis in the shape of the apical organ and mature proglottids, and from H. extensivum in testes number and scolex dimensions. The new species can be distinguished from one another based on the following combination of features: Hornellobothrium gerdaae n. sp. possesses testes arranged in 2 layers and lacks post-ovarian vitelline follicles; Hornellobothrium iotakotta n. sp. has a single column of 4 testes and lacks spiniform microtriches on the distal bothridial surface; both Hornellobothrium kolossakotta n. sp. and Hornellobothrium najaforme n. sp. possess a single column of 6 testes, but H. najaforme n. sp. is a longer worm with a greater number of laterally expanded immature proglottids. Host associations suggest this genus is potentially limited to A. ocellatus . While reports of up to 9 lecanicephalidean congeners in a single host species exist, they are considered dubious and in need of verification, mainly because of host identification issues. This study demonstrates the presence of at least 5 species of Hornellobothrium in A. ocellatus . Insufficient sampling of this host species across the Indo-Pacific and at each locality may account for the apparent restricted distribution of species of Hornellobothrium.

A New Species of Eagle Ray Aetobatus narutobiei from the Northwest Pacific: An Example of the Critical Role Taxonomy Plays in Fisheries and Ecological Sciences

Recent taxonomic and molecular work on the eagle rays (Family Myliobatidae) revealed a cryptic species in the northwest Pacific. This species is formally described as Aetobatus narutobiei sp. nov. and compared to its congeners. Aetobatus narutobiei is found in eastern Vietnam, Hong Kong, China, Korea and southern Japan. It was previously considered to be conspecific with Aetobatus flagellum, but these species differ in size, structure of the NADH2 and CO1 genes, some morphological and meristic characters and colouration. Aetobatus narutobiei is particularly abundant in Ariake Bay in southern Japan where it is considered a pest species that predates heavily on farmed bivalve stocks and is culled annually as part of a ‘predator control’ program. The discovery of A. narutobiei highlights the paucity of detailed taxonomic research on this group of rays. This discovery impacts on current conservation assessments of A. flagellum and these need to be revised based on the findings of this study.

Redescription of Aetobatus flagellum (Bloch & Schneider, 1801), an endangered eagle ray (Myliobatoidea: Myliobatidae) from the Indo–West Pacific

The eagle ray Aetobatus flagellum (Bloch & Schneider, 1801) is redescribed based on new material from the Persian Gulf (Kuwait), Indonesia and Malaysia. A related but distinct species of Aetobatus from the western North Pacific, previously referred to as A. flagellum, is reported. Aetobatus flagellum is a medium-sized eagle ray which attains about 900 mm DW; males mature at approximately 500 mm DW. Aetobatus flagellum appears to be uncommon and restricted to estuary-influenced waters of the Indo-West Pacific. It is caught as gillnet bycatch where its habit of schooling, combined with probable small litter size, may make it particularly vulnerable to impacts from fisheries.

Composition of elasmobranch landings in Bahrain

The first detailed elasmobranch fisheries data for the Kingdom of Bahrain are presented, based on surveys of fish markets in April 2012. At least 25 species were recorded, including undescribed taxa. The milk shark Rhizoprionodon acutus was the most frequently recorded species; together with the Arabian smoothhound Mustelus mosis and banded eagle ray Aetomylaeus nichofii, these species comprised 53% of individual abundance. Sharks were almost entirely small individuals <1 m total length (TL). Males of small shark species were largely mature, whereas nearly all individuals of larger sharks were immature. For several elasmobranch species, landings were significantly biased towards males, which were largely mature. The species assemblage showed some notable differences in composition to that of adjacent Qatar, sampled at the same time of year, highlighting the importance of local data collection.

Trophic transfer and accumulation of mercury in ray species in coastal waters affected by historic mercury mining (Gulf of Trieste, northern Adriatic Sea)

Total mercury (Hg) and monomethylmercury (MMHg) were analysed in the gills, liver and muscle of four cartilaginous fish species (top predators), namely, the eagle ray (Myliobatis aquila), the bull ray (Pteromylaeus bovinus), the pelagic stingray (Dasyatis violacea) and the common stingray (Dasyatis pastinaca), collected in the Gulf of Trieste, one of the most Hg-polluted areas in the Mediterranean and worldwide due to past mining activity in Idrija (West Slovenia). The highest Hg and MMHg concentrations expressed on a dry weight (d.w.) basis were found in the muscle of the pelagic stingray (mean, 2.529 mg/kg; range, 1.179-4.398 mg/kg, d.w.), followed by the bull ray (mean, 1.582 mg/kg; range, 0.129-3.050 mg/kg d.w.) and the eagle ray (mean, 0.222 mg/kg; range, 0.070-0.467 mg/kg, d.w.). Only one specimen of the common stingray was analysed, with a mean value in the muscle of 1.596 mg/kg, d.w. Hg and MMHg contents in the bull ray were found to be positively correlated with species length and weight. The highest MMHg accumulation was found in muscle tissue. Hg and MMHg were also found in two embryos of a bull ray, indicating Hg transfer from the mother during pregnancy. The number of specimens and the size coverage of the bull rays allowed an assessment of Hg accumulation with age. It was shown that in bigger bull ray specimens, the high uptake of inorganic Hg in the liver and the slower MMHg increase in the muscle were most probably due to the demethylation of MMHg in the liver. The highest Hg and MMHg contents in all organs were found in the pelagic stingray, which first appeared in the northern Adriatic in 1999. High Hg and MMHg concentrations were also found in prey species such as the banded murex (Hexaplex trunculus), the principal prey of the eagle rays and bull rays, the anchovy (Engraulis encrasicholus) and the red bandfish (Cepola rubescens), which are preyed upon by the pelagic stingray, as well as in zooplankton and seawater. Based on previously published data, a tentative estimation of MMHg bioamagnification was established. The average increase in MMHg between seawater, including phytoplankton, and zooplankton in the Gulf was about 10(4), and MMHg in anchovy was about 50-fold higher than in zooplankton. The bioaccumulation of MMHg between seawater and small pelagic fish (anchovy) amounted to 10(6) and between water and the muscle of larger pelagic fish (pelagic stingray) to 10(7). The MMHg increase between surface sediment and benthic invertebrates (murex) and between benthic invertebrates and small benthic fish was 10(2). Ultimately, the trophic transfer resulted in a 10(3) accumulation of MMHg between water and muscle of larger benthic fish (bull ray, eagle ray, common stingray), suggesting lower bioaccumulation by benthic feeding species.

Homing in the New Zealand eagle ray, Myliobatis tenuicaudatus

Homing after experimental displacement is widespread among bony fishes but has only been documented in two species of elasmobranchs, lemon sharks, Negaprion brevirostris, and Port Jackson sharks, Heterodontus portusjacksoni. To test if a species of batoid was capable of homing, New Zealand eagle rays, Myliobatis tenuicaudatus, were experimentally displaced 1.3–9.4 km from the Whangateau Estuary, where they feed, rest and are protected from predators. Significantly more rays returned to the estuary than expected by chance (seven out of eleven rays). The present study demonstrated for the first time that rays are capable of homing after experimental displacement. Homing success was not predicted by day or night capture, displacement distance, ray size, water depth at the displacement site or time in captivity. The homing rates and speeds of the rays were lower than those recorded for sharks, possibly due to a disparity in motivation and behavioural differences. Analysis of active tracks for associations with potential navigational stimuli may indicate which stimuli the rays use to home.

Two new species of Halysioncum Caira, Marques, Jensen, Kuchta et Ivanov, 2013 (Cestoda, Diphyllidea) from Indo-Pacific rays of the genus Aetomylaeus Garman (Myliobatiformes, Myliobatidae)

Recent collections of cestode parasites from two species of the myliobatid genus Aetomylaeus Garman from several localities in the Pacific Ocean resulted in the discovery of two new species of Halysioncum Caira, Marques, Jensen, Kuchta et Ivanov, 2013. Halysioncum gibsoni sp. n. from Aetomylaeus maculatus (Gray) in the South China Sea off Borneo differs from all of its congeners in having the following combination of characters: 27 apical hooks (14 type A and 13 type B hooks), 11-12 lateral hooklets, 22-28 spines per column on the cephalic peduncle, testes distributed in a single column and an internal seminal vesicle. Halysioncum arafurense sp. n., recovered from Aetomylaeus cf. nichofii 2 (sensu Naylor et al. 2012b) in the Arafura Sea off the Wessel Islands, Northern Territory, Australia, can be distinguished from its congeners based on the following combination of characters: 23 apical hooks (12 type A and 11 type B hooks), the number of lateral hooklets (9-11), the number of spines per column on the cephalic peduncle (20-24), the number and distribution of the testes (13-15 testes in two irregular columns), and the distribution of vitelline follicles (interrupted dorsally at the level of the ovarian lobes). Both species represent the first verified records of diphyllideans from eagle rays of the genus Aetomylaeus and formally extend the host associations of diphyllideans to include a third genus of Myliobatiformes. The myliobatiforms are indeed an understudied group of available hosts for diphyllideans and represent interesting target hosts if the diversity of diphyllidean tapeworms is to be fully estimated and understood.

Uterine dynamics of the southern eagle ray Myliobatis goodei (Chondrichthyes: Myliobatidae) from the southwest Atlantic Ocean

Uterine layer changes and their relationship with the reproductive cycle were analyzed for the southern eagle ray Myliobatis goodei (Chondrichthyes: Myliobatidae), based on histological and histometric studies. The specimens were collected from bottom-trawl surveys conducted in the coastal southwest Atlantic ecosystem between latitude 34 and 42°S. Oviduct samples were removed and fixed in 10% buffered formalin until processing for histological analysis. Both oviducts are developed in mature females, but only the left is functional. After ovulation, the size of the right posterior oviduct decreases and the left develops into a complex uterus that occupies almost the entire coelomic cavity. This uterus undergoes successive morphological and functional changes related to reproductive stages. Mucosa was characterized by temporal villous extensions or trophonemata with high variability depending on reproductive events. Invaginations or crypts associated with presumably lipid secretion (histotrophe) were observed between the trophonematum bases. The muscular layer develops into a complex muscular-vascular-conjunctive structure. The nutrition of early-gestation embryos is lecithotrophic and later they receive nutrients from the yolk sac and histotrophe. After yolk depletion, embryos become entirely dependent on histotrophe. Uterolactation, presumptive water imbibition of the muscular layer, and uterine hypertrophy observed in this study reinforce the “similarities” between Myliobatiformes and mammals.

Epitheliocystis hyperinfection in captive spotted eagle rays Aetobatus narinari associated with a novel Chlamydiales 16S rDNA signature sequence

This report details 2 cases of epitheliocystis in spotted eagle rays Aetobatus narinari associated with a novel Chlamydiales 16S rDNA signature sequence. Epitheliocystis is a common disease of variable severity affecting >50 species of wild and cultured freshwater and marine teleosts. Disease in elasmobranchs is rarely reported and descriptions are limited. Occurring in gill and skin epithelium, lesions are characterized by large hypertrophied cells with basophilic inclusions containing Gram-negative, chlamydia-like bacteria. Acute lethargy, labored respiration, and abnormal swimming developed in a captive spotted eagle ray following an uneventful quarantine period, and mild epitheliocystis lesions were found microscopically. Three months later, a second animal exhibited similar signs. A gill clip revealed myriad spherical bodies identical to the previous case, and treatment with chloramphenicol and oxytetracycline was initiated. Despite therapy, respiration became irregular and euthanasia was elected. Histologically, epitheliocystis inclusions up to 200 µm filled approximately 80% of lamellar troughs. Multifocal mild hypertrophy and hyperplasia of lamellar tips was accompanied by mild to moderate infiltrates of granulocytes and lymphocytes. Electron microscopy revealed a homogeneous population of elongate chlamydia-like bacterial forms similar in size and morphology to the primary long cells described in teleosts. Immunohistochemical staining with a polyclonal anti-chlamydial lipopolysaccharide antibody was positive. Sequence analysis of a unique 296 bp Chlamydiales signature sequence amplicon isolated from the rays showed greatest homology (85 to 87%) to 'Candidatus Piscichlamydia salmonis'.

Some new Eocene elasmobranch reports from the Outer Western Carpathians (Moravia, Czech Republic)

The Eocene deposits from the Stare Město locality (Frýdlant Formation, Subsilesian Unit) provided fossil fish remains, which can be assigned to two elasmobranch taxa: the eagle ray Leidybatis jugosus and the shark Centrophorus sp. The specimens are represented by associated dental plates and isolated teeth. This is the first record of L. jugosus in the Czech portion of the Western Carpathians and is thus the second record for the entire Carpathian area. Presence of the taxon confirms the Eocene age of the deposits. The common occurrence with genus Centrophorus suggests sedimentation in deeper conditions (> 200 m). Other material (obtained by microvertebrate preparation technique), isolated dermal denticles and calcified cartilage prisms, are described using open nomenclature (Myliobatoidei indet. and ?Myliobatiformes indet., respectively).

Availability of vulnerable elasmobranches in the marine water of Bangladesh

A study was conducted about vulnerable shark and ray species availability and their percentage composition in two fish landing centers at Fishery ghat, Chittagong and BFDC fish harbor, Cox’s Bazar district during April 2006 through March 2012. A total of 35 species (11 shark and 24 ray species) was identified within these six years. Out of 35 species, only one vulnerable shark species, the silky shark Carcharhinus falciformis (Muller and Henle, 1839), was not abundant all the year round and three were vulnerable ray species, Javanese cow ray Rhinoptera javanica (Muller and Henle, 1841), banded eagle ray Aetomylaeus nichofii (Bloch and Schneider, 1801) and white spotted shovelnose ray Rhynchobatus laevis (Bloch and Schneider 1801) were found throughout the year during the study period. The average percentage composition by weight of C. falciformis was 1.38 and the availability of average number was 3202. The average percentage contribution and the landed average number of vulnerable R. javanica, A. nichofii and R. laevis species were 1.46% (948 numbers), 0.61% (554 numbers) and 0.54% (298 numbers), respectively of the total catch. DOI: http://dx.doi.org/10.3329/bjz.v40i2.14316 Bangladesh J. Zool. 40(2): 221-229, 2012

Paternity testing using the poisonous sting in captive white‐spotted eagle rays Aetobatus narinari: a non‐invasive tool for captive sustainability programmes

A group of captive white-spotted eagle rays Aetobatus narinari produced 20 offspring, with an unknown father. Part of the poisonous sting was removed from each fish and DNA was extracted from the epidermis for paternity research using eight microsatellite markers of which four were from another species Aetobatus flagellum. This non-invasive sampling technique can be applied on all members of Myliobatiformes.

Temporal changes in some Rajiformes species of cartilaginous fish (Chondrichthyes) from the west coast of İskenderun Bay (northeastern Mediterranean)

Some Rajiformes species among the cartilaginous fish (Chondrichthyes) that are distributed on the west coast of the Gulf of Iskenderun were seasonally obtained by bottom trawling from 2 different depth layers between the years 2004 and 2011. The spatiotemporal changes in catch per unit effort (CPUE) values were investigated by considering 2 depth contours (10 and 20 m). Six species belonging to 6 different Rajiformes families were identified during the sampling period, including Dasyatis pastinaca (common stingray), Gymnura altavela (spiny butterfly ray), Rhinobatos rhinobatos (common guitarfish), Raja radula (rough ray), Myliobatis aquila (common eagle ray), and Torpedo marmorata (marbled electric ray). A general linear model was used to analyze the changes in the total and separate weights of cartilaginous fish. For this purpose, the logarithms of CPUE values in weight were classed according to the depth, season, and years. Seasonal variations and year–season 2-way interactions were found to be highly significant for total cartilaginous CPUE values (P < 0.01). The annual changes in R. rhinobatos were the only significant annual difference (P < 0.05), while the year–season interactions of D. pastinaca were found to be significant (P < 0.01). The seasonal variations of D. pastinaca and G. altavela were also highly significant (P < 0.01).

An overview of the hooking mortality of elasmobranchs caught in a swordfish pelagic longline fishery in the Atlantic Ocean

Hooking (or at-haulback) fishing mortality was analysed in elasmobranchs captured by Portuguese long- liners targeting swordfish in the Atlantic Ocean. Information was collected by on-board fishery observers who moni- tored 834 longline fishing sets between August 2008 and December 2011, and recorded information on 36 067 elasmo- branch specimens from 21 different taxa. The hooking mortality proportions were species-specific, with some species having relatively high percentages of live specimens at time of haulback (e.g., blue shark, crocodile shark, pelagic stingray, manta, devil and eagle rays), while others had higher percentages of dead specimens (e.g., smooth hammer- head, silky shark, bigeye thresher). For the most captured species (Prionace glauca, Pseudocarcharias kamoharai, Isurus oxyrinchus and Alopias superciliosus), logistic generalized linear models (GLMs) were carried out to compare the mortality rates between sexes, specimen sizes and the regions of operation of the fleet. The sex-specific proportions of hooking mortality were significantly different for blue and crocodile sharks, with the males of both species having higher proportions of hooking mortality than the females. Specimen size was significant for predicting the hooking mortality for blue and shortfin mako sharks: in both cases, the larger specimens had lower odds of dying due to the fishing process. There were differences in the hooking mortality depending on the region of operation of the fleet, but those differences were also species-specific. For blue and crocodile sharks, the hooking mortality was higher in the Equatorial and southern Atlantic areas (when compared to the NE Atlantic region), while the opposite was observed for the shortfin mako, with lower mortality rates in the NE tropical area compared with the other regions. The results presented in this paper can be integrated into future ecological risk assessment analysis for pelagic elasmobranchs. Fur- thermore, the new information can be used to evaluate the impact of recent recommendations prohibiting the retention of some vulnerable elasmobranch species.

Renal patient's diet: Can fish be included?

Medical and nutritional treatment for renal disease, now a major public health issue, is highly complicated. Nutritional therapy must seek to retard renal dysfunction, maintain an optimal nutritional status and prevent the development of underlying pathologies. To analyze ten fish species to identify those that, because of their low phosphorus content, high biological value protein and elevated n-3 fatty acids EPA and DHA, could be included in renal patient's diet. The following fish species (Litte tunny, Red drum, Spotted eagleray, Escolar, Swordfish, Big-scale pomfret, Cortez flounder, Largemouth blackbass, Periche mojarra, Florida Pompano) were analyzed according to the AOAC and Keller techniques to determine their protein, phosphorus, sodium, potassium, cholesterol, vitamins D(3) and E, and n-3 EPA+DHA content. These results were used to calculate relations between nutrients. The protein in the analyzed species ranged from 16.5 g/100 g of fillet (Largemouth black bass) to 27.2 g/100 g (Red drum); the lowest phosphorus value was 28.6 mg/100 g (Periche mojarra) and the highest 216.3 mg/100 g (Spotted eagle ray). 80% of the fish presented > 100 mg EPA + DHA in 100 g of fillet. By its Phosphorus/gProtein ratio, Escolar and Swordfish could not be included in the renal diet; Little tunny, Escolar, Big-scale pomfret, Largemouth black-bass, Periche mojarra and Florida Pompano presented a lower Phosphorus/EPA + DHA ratio. Florida pompano is the most recommended specie for renal patients, due to its optimal nutrient relations. However, all analyzed species, except Escolar and Swordfish, could be included in renal diets.