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1.
Syst Parasitol ; 101(4): 51, 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-39017770

RESUMO

Troglocephalinae n. subfam. is proposed for Spinuris Doran, 1953, Neoheterocotyle Hargis, 1955, Anoplocotyloides Young, 1967, Troglocephalus rhinobatidis Young, 1967 (previously incertae sedis), Nonacotyle pristis Ogawa, 1991, Mehracotyle insolita Neifar, Euzet & Ben Hassine, 2002, Scuticotyle cairae n. gen. et sp., and Brancheocotyle imbricata n. gen. et sp. All members of the proposed new subfamily are gill parasites of shovelnose rays of the order Rhinopristiformes. The subfamilies Heterocotylinae Chisholm, Wheeler & Beverley-Burton, 1995, and Dasybatotreminae Bychowsky, 1957, are amended to exclude Spinuris, Nonacotyle, Neoheterocotyle, and Anoplocotyloides and Mehracotyle, respectively. Heterocotylinae includes gill parasites of members of the orders Myliobatiformes and Torpediniformes. Dasybatotreminae includes parasites of the gills and pharyngeal cavity of members of the orders Myliobatiformes and Rajiformes. A revised phylogeny of the Monocotylidae Taschenberg, 1879 is presented and discussed, based on 28S rDNA sequences, including new sequences for Myliocotyle pteromylaei Neifer, Euzet & Ben Hassine, 1999, Heterocotyle tokoloshei Vaughan & Chisholm, 2010, Neoheterocotyle robii Vaughan & Chisholm, 2010, and the two newly proposed species and genera. Additional locality records are also provided for Monocotylidae from off South Africa.


Assuntos
Brânquias , Rajidae , Especificidade da Espécie , Trematódeos , Animais , Brânquias/parasitologia , Trematódeos/classificação , Trematódeos/genética , Trematódeos/anatomia & histologia , Rajidae/parasitologia , Filogenia , RNA Ribossômico 28S/genética
2.
Curr Biol ; 34(12): 2773-2781.e3, 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38843829

RESUMO

Across vertebrates, live bearing evolved at least 150 times from ancestral egg laying into diverse forms and degrees of prepartum maternal investment.1,2 A key question is how reproductive diversity arose and whether reproductive diversification underlies species diversification.3,4,5,6,7,8,9,10,11 To test this, we evaluate the most basal jawed vertebrates: the sharks, rays, and chimaeras, which have one of the greatest ranges of reproductive and ecological diversity among vertebrates.2,12 We reconstruct the sequence of reproductive mode evolution across a phylogeny of 610 chondrichthyans.13 We reveal egg laying as ancestral, with live bearing evolving at least seven times. Matrotrophy evolved at least 15 times, with evidence of one reversal. In sharks, transitions to live bearing and matrotrophy are more prevalent in larger-bodied tropical species. Further, the evolution of live bearing is associated with a near doubling of the diversification rate, but there is only a small increase associated with the appearance of matrotrophy. Although pre-copulatory sexual selection is associated with increased rates of speciation in teleosts,3 sexual size dimorphism in chondrichthyans does not appear to be related to sexual selection,14,15 and instead we find increased rates of speciation associated with the colonization of novel habitats. This highlights a potential key difference between chondrichthyans and other fishes, specifically a slower rate of evolution of reproductive isolation following speciation, suggesting different rate-limiting mechanisms for diversification between these clades.16 The chondrichthyan diversification and radiation, particularly throughout shallow tropical shelf seas and oceanic pelagic habitats, appear to be associated with the evolution of live bearing and proliferation of a wide range of maternal investment in developing offspring.


Assuntos
Evolução Biológica , Tamanho Corporal , Filogenia , Tubarões , Rajidae , Animais , Tubarões/fisiologia , Tubarões/anatomia & histologia , Tubarões/genética , Rajidae/fisiologia , Rajidae/genética , Rajidae/anatomia & histologia , Feminino , Reprodução , Masculino
3.
Nat Ecol Evol ; 8(6): 1118-1128, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38769434

RESUMO

Many shark populations are in decline around the world, with severe ecological and economic consequences. Fisheries management and marine protected areas (MPAs) have both been heralded as solutions. However, the effectiveness of MPAs alone is questionable, particularly for globally threatened sharks and rays ('elasmobranchs'), with little known about how fisheries management and MPAs interact to conserve these species. Here we use a dedicated global survey of coral reef elasmobranchs to assess 66 fully protected areas embedded within a range of fisheries management regimes across 36 countries. We show that conservation benefits were primarily for reef-associated sharks, which were twice as abundant in fully protected areas compared with areas open to fishing. Conservation benefits were greatest in large protected areas that incorporate distinct reefs. However, the same benefits were not evident for rays or wide-ranging sharks that are both economically and ecologically important while also threatened with extinction. We show that conservation benefits from fully protected areas are close to doubled when embedded within areas of effective fisheries management, highlighting the importance of a mixed management approach of both effective fisheries management and well-designed fully protected areas to conserve tropical elasmobranch assemblages globally.


Assuntos
Conservação dos Recursos Naturais , Recifes de Corais , Pesqueiros , Tubarões , Rajidae , Animais , Conservação dos Recursos Naturais/métodos
4.
J Anim Ecol ; 93(7): 876-890, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38778676

RESUMO

Interspecific interactions, including predator-prey, intraguild predation (IGP) and competition, may drive distribution and habitat use of predator communities. However, elucidating the relative importance of these interactions in shaping predator distributions is challenging, especially in marine communities comprising highly mobile species. We used individual-based models (IBMs) to predict the habitat distributions of apex predators, intraguild (IG) prey and prey. We then used passive acoustic telemetry to test these predictions in a subtropical marine predator community consisting of eight elasmobranch (i.e. shark and ray) species in Bimini, The Bahamas. IBMs predicted that prey and IG prey will preferentially select habitats based on safety over resources (food), with stronger selection for safe habitat by smaller prey. Elasmobranch space-use patterns matched these predictions. Species with predator-prey and asymmetrical IGP (between apex and small mesopredators) interactions showed the clearest spatial separation, followed by asymmetrical IGP among apex and large mesopredators. Competitors showed greater spatial overlap although with finer-scale differences in microhabitat use. Our study suggests space-use patterns in elasmobranchs are at least partially driven by interspecific interactions, with stronger spatial separation occurring where interactions include predator-prey relationships or IGP.


Assuntos
Ecossistema , Cadeia Alimentar , Comportamento Predatório , Tubarões , Animais , Tubarões/fisiologia , Rajidae/fisiologia , Bahamas , Modelos Biológicos , Distribuição Animal , Telemetria
5.
Invertebr Syst ; 382024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38744525

RESUMO

The rhinebothriidean tapeworm family Escherbothriidae has recently been expanded to include the genus Ivanovcestus , species of which parasitise arhynchobatid skates. Similarities in morphology and host associations between Ivanovcestus and Semiorbiseptum - a genus yet to be assigned to one of the families in the order Rhinebothriidea - led us to explore the possibility that Semiorbiseptum might also belong in the Escherbothriidae. Morphological similarities with Scalithrium ivanovae , Scalithrium kirchneri and Rhinebothrium scobinae , all of which also parasitise arhynchobatid skates, raised questions regarding the generic placements of these species. In addition, new collections from the skate Sympterygia brevicaudata revealed two new species that morphologically resemble species of Ivanovcestus . A combination of morphological and molecular data were used to assess the generic placement of the newly discovered species and refine our understanding of the membership of the family Escherbothriidae. Sequence data for the D1-D3 region of the 28S rDNA gene were generated de novo for 14 specimens of 7 rhinebothriidean species and combined with comparable published data to represent all 6 families in the Rhinebothriidea in the analysis. The phylogenetic tree resulting from maximum likelihood analysis strongly supports the inclusion of the genus Semiorbiseptum in the family Escherbothriidae. Our work also suggests that the skate-hosted species previously assigned to Scalithrium and Rhinebothrium are also members of Semiorbiseptum and that Ivanovcestus is a junior synonym of Semiorbiseptum . Six species are transferred to Semiorbiseptum , bringing the total number of species in the genus to ten. The diagnosis of Semiorbiseptum is amended to accommodate the additional species. A second species in the previously monotypic type genus of the family, Escherbothrium , is described. The diagnosis of the Escherbothriidae is amended to include the new and transferred species. This study underscores the importance of integrating morphological and molecular data in bringing resolution to cestode systematics. We believe our findings provide a robust foundation for future research into the evolutionary history and host associations of cestodes within the order Rhinebothriidea and beyond. These also highlight the importance of expanding our understanding of skate-hosted cestodes. ZooBank: urn:lsid:zoobank.org:pub:8052AFCA-5FBD-4430-95F4-0E5E368DEA3D.


Assuntos
Cestoides , Filogenia , Rajidae , Cestoides/genética , Cestoides/classificação , Animais , Rajidae/parasitologia , Especificidade da Espécie , RNA Ribossômico 28S/genética
6.
An Acad Bras Cienc ; 96(2): e20231083, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38747840

RESUMO

This paper describes the fishing profile and the temporal variation in the commercial landings of elasmobranchs in a global hotspot for their conservation and investigates the variables that influenced the landings. Census data on commercial catches were obtained between April 2008 and October 2010 from nine landing sites in Bragança (Pará, northern Brazil). Five vessel types, four fishing gears, and eight fishing techniques engaged with elasmobranch capture were identified. A total of 2,357 landings were recorded, with a total production of 354 t. The highest yields were recorded in 2009, with sharks being harvested mostly by small and medium-sized vessels, and batoids, by small vessels and canoes. Drifting nets and longlines played a prominent role in elasmobranch fisheries. The results show that the landings were influenced by days at sea, which is common in tropical fisheries. The elasmobranch data series is discontinuous as statistics are absent for most fishing sites albeit imperative for proper management, as well as relevant for decision-makers focusing on their conservation.


Assuntos
Conservação dos Recursos Naturais , Pesqueiros , Tubarões , Animais , Tubarões/classificação , Brasil , Elasmobrânquios/classificação , Estações do Ano , Rajidae/classificação
7.
Wilderness Environ Med ; 35(2): 166-172, 2024 06.
Artigo em Inglês | MEDLINE | ID: mdl-38620041

RESUMO

INTRODUCTION: Current literature on stingray envenomations focuses on the incidence, presentation, and complications of these injuries, with some studies providing such data for specific geographic locations. This is the first study to evaluate the influence of environmental factors and human characteristics on stingray envenomation patterns in San Diego, California. METHODS: Incident reports of injuries documented by the San Diego Fire-Rescue Department/Lifeguard Division (SDFR-LG) during 2017 were analyzed. Water temperature and tide height were populated based on date and time. Data was analyzed for associations between stingray injuries incidence and tide height, water temperature, time, month, age and sex of the injured person, and whether they were local. RESULTS: 1722 stingray injuries were reported to the SDFR-LG in 2017. Stingray injuries were associated with water temperature (p < 0.001), more frequently occurring between 18.8 °C and 19.5 °C. Most envenomations occurred at tide heights between 1.7 ft and 3.1 ft. Most victims were aged 20-29, and there were more males than females injured. Beaches separated from the greater ocean or with a reef bottom had a lower incidence. Stingray injuries were more frequent during summer months. More stingray envenomations were documented for out-of-town beachgoers. CONCLUSIONS: Beachgoers with certain characteristics had more reported stingray envenomations than others. Males, nonlocal beachgoers, and individuals in their twenties had more injuries than their counterparts. Stingray injuries were more common at water temperatures between 18.8 and 19.5 °C. These findings may lead to future research on the prevention of stingray injuries.


Assuntos
Mordeduras e Picadas , Rajidae , Humanos , Mordeduras e Picadas/epidemiologia , California/epidemiologia , Masculino , Feminino , Adulto , Animais , Fatores de Risco , Adulto Jovem , Pessoa de Meia-Idade , Adolescente , Criança , Pré-Escolar , Incidência , Idoso , Lactente , Temperatura
8.
J Morphol ; 285(5): e21698, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38669130

RESUMO

The glycosylation of macromolecules can vary both among tissue structural components and by adverse conditions, potentially providing an alternative marker of stress in organisms. Lectins are proteins that bind carbohydrate moieties and lectin histochemistry is a common method to visualize microstructures in biological specimens and diagnose pathophysiological states in human tissues known to alter glycan profiles. However, this technique is not commonly used to assess broad-spectrum changes in cellular glycosylation in response to environmental stressors. In addition, the binding of various lectins has not been studied in elasmobranchs (sharks, skates, and rays). We surveyed the binding tissue structure specificity of 14 plant-derived lectins, using both immunoblotting and immunofluorescence, in the pectoral fins of neonate little skates (Leucoraja erinacea). Skates were reared under present-day or elevated (+5°C above ambient) temperature regimes and evaluated for lectin binding as an indicator of changing cellular glycosylation and tissue structure. Lectin labeling was highly tissue and microstructure specific. Dot blots revealed no significant changes in lectin binding between temperature regimes. In addition, lectins only detected in the elevated temperature treatment were Canavalia ensiformis lectin (Concanavalin A) in spindle cells of muscle and Ricinus communis agglutinin in muscle capillaries. These results provide a reference for lectin labeling in elasmobranch tissue that may aid future investigations.


Assuntos
Lectinas , Temperatura , Animais , Lectinas/metabolismo , Nadadeiras de Animais , Rajidae , Glicosilação , Animais Recém-Nascidos , Ligação Proteica
9.
Folia Parasitol (Praha) ; 712024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38505977

RESUMO

Four new diphyllidean species of the genus Echinobothrium van Beneden, 1849 are described from Indo-Pacific maskrays (Neotrygon Castelnau, Dasyatidae). Echinobothrium giraffaeous sp. n. from Neotrygon leylandi (Last) off northern Australia, Echinobothrium ivanovae sp. n. from Neotrygon orientalis Last, White et Serét off Borneo, and Echinobothrium bethae sp. n. from Neotrygon varidens (Garman) off Borneo are distinguished from all but one of the 33 valid species of the genus by the possession of the outermost A hooks with an extended base into which the bases of the three outermost B hooks are inserted. Echinobothrium rhynchobati (Khalil et Abdul-Salam, 1989) is the only known species with this unique feature, but its rostellum has a system of interlocking knobs and sockets that articulate bases of the A and B type hooks with one another, which is not present in any of the newly described species. Echinobothrium tyleri sp. n. from Neotrygon australiae Last, White et Serét off northern Australia is distinguished from all known species of Echinobothrium by its unique rostellar hook formula {2-3 18/17 2-3}. With the present addition of four new species, the central Indo-Pacific realm becomes the major hotspot for Echinobothrium, from which 13 species have been reported.


Assuntos
Cestoides , Doenças dos Peixes , Rajidae , Animais , Bornéu , Austrália/epidemiologia
10.
J Fish Biol ; 104(6): 1875-1887, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38501373

RESUMO

The short-tail yellownose skate, Zearaja brevicaudata, occurs off southern Brazil and along the Argentine continental shelf, including waters surrounding the Islas Malvinas and the upper slope, and is very frequently caught by trawl fisheries throughout its range. The age, growth, and maturity of Z. brevicaudata were investigated using 204 individuals collected by commercial fishing vessels from northern Argentina, between March 2016 and September 2019. Age was determined on a sample comprising vertebrae from 151 individuals, 60 males, ranging in size from 391 to 956 mm total length (TL), and 91 females, ranging in size from 324 to 1060 mm TL. Maximum ages determined for males and females were 22 and 29 years, respectively. A Bayesian framework was employed with a set of three candidate models to estimate growth parameters (von Bertalanffy, Gompertz, and Logistic). The von Bertalanffy model had the best fit, and the sexes showed undistinguishable growth parameters. For sexes combined, derived growth mean parameters (± S.D.) were L∞ = 1081 mm ± 64.34 mm, k = 0.09 ± 0.01 years-1, and L0 = 248 mm ± 23.52 mm. The age at maturity was estimated at 13.15 and 14.66 years for males and females, respectively.


Assuntos
Rajidae , Animais , Rajidae/crescimento & desenvolvimento , Masculino , Feminino , Argentina , Características de História de Vida , Pesqueiros , Teorema de Bayes , Brasil , Maturidade Sexual , Tamanho Corporal
11.
J Fish Dis ; 47(7): e13946, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38492214

RESUMO

An adult female Brazilian cownose ray (Rhinoptera brasiliensis), housed in Ubatuba Aquarium died after loss of appetite period. During necropsy, an enterolith was discovered partially obstructing the intestinal lumen. Examination of the enterolith revealed a bonefish spine nidus. Enterolithiasis has been linked to multiple factors including diet, genetics, alkaline intestinal environments and, as in this particular case, the ingestion and retention of foreign bodies. The composition of this enterolith from a cownose ray was primarily monohydrocalcite. This short communication, apparently the first to report enterolithiasis in stingrays, emphasizes the need for post-mortem examinations of carcasses on macroscopic and microscopic levels.


Assuntos
Doenças dos Peixes , Rajidae , Animais , Doenças dos Peixes/patologia , Feminino , Corpos Estranhos/veterinária , Corpos Estranhos/patologia , Brasil
12.
Science ; 383(6687): 1135-1141, 2024 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-38452078

RESUMO

The deep ocean is the last natural biodiversity refuge from the reach of human activities. Deepwater sharks and rays are among the most sensitive marine vertebrates to overexploitation. One-third of threatened deepwater sharks are targeted, and half the species targeted for the international liver-oil trade are threatened with extinction. Steep population declines cannot be easily reversed owing to long generation lengths, low recovery potentials, and the near absence of management. Depth and spatial limits to fishing activity could improve conservation when implemented alongside catch regulations, bycatch mitigation, and international trade regulation. Deepwater sharks and rays require immediate trade and fishing regulations to prevent irreversible defaunation and promote recovery of this threatened megafauna group.


Assuntos
Conservação dos Recursos Naturais , Extinção Biológica , Caça , Tubarões , Rajidae , Animais , Humanos , Internacionalidade , Carne , Óleos de Peixe , Biodiversidade , Oceanos e Mares , Risco
13.
Environ Pollut ; 346: 123570, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38360387

RESUMO

Subsea power cables cause electromagnetic fields (EMFs) into the marine environment. Elasmobranchs (rays, skates, sharks) are particularly sensitive to EMFs as they use electromagnetic-receptive sensory systems for orientation, navigation, and locating conspecifics or buried prey. Cables may intersect with egg laying sites, mating, pupping, and nursery grounds, foraging habitat and migration routes of elasmobranchs and the effects of encountering EMFs on species of elasmobranchs are largely unknown. Demonstrated behavioural effects are attraction, disturbance and indifference, depending on EMF characteristics, exposed life stage, exposure level and duration. We estimated exposure levels of elasmobranchs to subsea power cable EMFs, based on modelled magnetic fields in the Dutch Continental Shelf and compared these to reported elasmobranch sensory sensitivity ranges and experimental effect levels. We conclude that the risk from subsea power cables has a large uncertainty and varies per life stage and species ecology. Based on estimated no-observed effect levels (from 10-3 to 10-1 µT) we discuss what will probably be the most affected species and life stage for six common benthic elasmobranchs in the Southern North Sea. We then identify critical knowledge gaps for reducing the uncertainty in the risk assessments for EMFs effects on benthic elasmobranchs.


Assuntos
Tubarões , Rajidae , Animais , Campos Eletromagnéticos , Ecossistema , Comportamento Animal
15.
J Fish Biol ; 104(6): 1698-1708, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38420688

RESUMO

Knowledge of thermal tolerance limits provides important clues to the capacity of a species to withstand acute and chronic thermal changes. Climate models predict the increase and intensification of events such as heat waves, therefore understanding the upper thermal limits that a species can tolerate has become of utmost importance. We measured the upper thermal tolerance of the endemic Magdalena river stingray Potamotrygon magdalenae acclimated to experimental conditions, and then used critical thermal methodology to find the temperature at which an organism reaches a critical endpoint where locomotory activity becomes disorganized and the animal loses its ability to escape from conditions that will promptly lead to its death. We also describe the behavioral response of individuals to acute thermal stress and infer the possible consequences of temperature increases in the habitats of P. magdalenae populations. There were no significant differences between sexes in temperature tolerance or behavior. The critical thermal maximum (39°C) was 5.9°C above the maximum recorded temperature for the study area. Although P. magdalenae was tolerant to high temperature and currently is not living at its upper thermal limit, its survival in Guarinocito Pond will be threatened if temperatures continue to increase, considering the warming scenarios predicted for tropical regions due to climate change, even including short-term climate phenomena such as El Niño.


Assuntos
Rajidae , Animais , Masculino , Rajidae/fisiologia , Feminino , Rios , Termotolerância , Temperatura , Temperatura Alta , Comportamento Animal , Aclimatação
16.
J Fish Biol ; 104(5): 1628-1632, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38332477

RESUMO

Recent encounters with sicklefin (Mobula tarapacana) and bentfin (Mobula thurstoni) devil rays in the Chagos Archipelago provide the first confirmed observations of live specimens of these species in this region. Examination of illegal fishing photo archives collected during enforcement revealed these endangered species, and spinetail devil rays (Mobula mobular), are being caught within the archipelago's vast no-take marine protected area. Future cooperation between authorities and mobulid ray experts is crucial to improve the availability and accuracy of enforcement data and improve management of illegal fishing and mobulid ray conservation activities.


Assuntos
Conservação dos Recursos Naturais , Espécies em Perigo de Extinção , Rajidae , Animais
17.
J Fish Biol ; 104(5): 1645-1650, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38402691

RESUMO

Areas of importance to Southern Ocean skates are poorly defined. Here, we identify a deepwater skate egg case nursery in a discrete location at ~460 m depth off Cape Adare in the Southern Ocean. This is the first confirmed observation of a skate nursery area in the Ross Sea and only the second observation for the Southern Ocean. The morphology and size of the egg cases were consistent with the genus Bathyraja and most likely belong to the Bathyraja sp. (cf. eatonii). The nursery occurs within the "no take" General Protection Zone of the Ross Sea region marine protected area, where commercial fishing is prohibited.


Assuntos
Oceanos e Mares , Óvulo , Rajidae , Animais , Feminino
18.
J Fish Biol ; 104(5): 1513-1524, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38403290

RESUMO

Management of thorny skate (Amblyraja radiata) in the Northwest Atlantic has posed a conservation dilemma for several decades due to the species' lack of response to strong conservation efforts in the US Gulf of Maine and the Canadian Scotian Shelf, confusion over the relationship between two reproductive size morphs of differing life histories that are sympatric in the Northwest Atlantic, and conflicting data on regional population connectivity throughout the species' broader range. To better assess potential A. radiata regional population differentiation and genetic links to life-history variation, we analysed complete mitochondrial genome sequences from 527 specimens collected across the species' North Atlantic geographic range, with particular emphasis on the Northwest Atlantic region. A high level of genetic diversity was evident across the North Atlantic, but significant genetic differentiation was identified between specimens inhabiting the Northwest (Gulf of Maine and Newfoundland) and Northeast (Greenland, Iceland, North Sea, and Arctic Circle) Atlantic. In the Northwest Atlantic, significant differentiation between the Gulf of Maine and Newfoundland regions was revealed; however, the overall level of differentiation was very low. No genetic difference was identified between the large and small reproductive morphs. The results of this study advance our understanding of A. radiata population structure in the North Atlantic but do not resolve all the questions confounding our understanding of the species' biology and evolutionary history.


Assuntos
Variação Genética , Genoma Mitocondrial , Rajidae , Animais , Rajidae/genética , Oceano Atlântico , Genética Populacional , Maine
19.
J Fish Biol ; 104(5): 1587-1602, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38417833

RESUMO

Round rays (family: Urotrygonidae) are commonly caught as by-catch by shrimp trawl fisheries in the tropical eastern Pacific (TEP). However, little information on their life history and catch species composition exists for most round ray species, preventing the evaluation of the impact of fishing on their populations. The mean size at sexual maturity (DW50), seasonal variation by maturity stages, and fecundity for two round ray species caught during shrimp trawl research cruises in the south-eastern Gulf of California (northern TEP) were estimated using a multi-model approach and inference for the first time, to determine the part of the population of each species that is being affected by shrimp trawling. Disc width (DW) ranged from 7.0 to 30.9 cm for the spotted round ray (Urobatis maculatus), and 7.2-33.5 cm for the thorny stingray (Urotrygon rogersi), with females reaching larger sizes than males in both species. The DW50 was estimated at 12.8 and 11.8 cm DW for the males and females of U. maculatus, respectively, whereas for U.rogersi, it was 15.0 and 18.4 cm DW for males and females, respectively. Embryos were found in females ≥14.5 cm DW in both species. The maximum fecundity was five embryos for U. maculatus (mean = 3.1 ± 0.2 S.E., mode = 4), and six embryos for U. rogersi (mean = 3.0 ± 0.3 S.E., mode = 2). Fecundity and embryo size did not vary with maternal size. Male and female immature and mature individuals for both species, including pregnant females, were found in the catches in all seasons of the year. Our results can help determine the vulnerability of the studied species populations to fishing pressure from shrimp trawling in the northern TEP and guide the development of future monitoring strategies and conservation actions for these species, if necessary.


Assuntos
Tamanho Corporal , Fertilidade , Estações do Ano , Maturidade Sexual , Rajidae , Animais , Rajidae/fisiologia , Rajidae/crescimento & desenvolvimento , Feminino , Masculino , Oceano Pacífico , Pesqueiros
20.
J Zoo Wildl Med ; 54(4): 704-712, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38251993

RESUMO

Cownose rays (Rhinoptera bonasus) are common elasmobranchs in zoos and aquaria; however, there is a lack of published information regarding ocular findings in this species. Intraocular pressure (IOP) was measured in a total of 52 cownose rays (Rhinoptera bonasus) from two unrelated aquaria (n = 22 from A1, n = 30 from A2) using a TonoVet rebound tonometer on two settings (dog = D, and unidentified species = P) as part of a full ophthalmologic examination. Adult (n = 38) and juvenile (n = 14) rays were sampled out of water briefly in sternal recumbency. Intraocular pressure (mean ± SD [range]) in the D setting (9.10 ± 2.57 [4-18] mmHg) was higher than the P setting (5.21 ± 2.32 [0-12] mmHg) (P<0.001). Statistical analysis revealed no difference in IOP between right and left eyes, and no correlation between body weight and IOP. No differences in IOP between sex, age group, and location were identified in either setting. However, a significant difference was observed between levels of severity of corneal disease in IOP D setting (P=0.006) and P setting (P=0.024), and levels of severity of intraocular disease in IOP D setting (P=0.034) only. This study provides baseline IOP values using rebound tonometry in aquarium-housed cownose rays with apparent corneal and intraocular lesions and reveals that the D setting may be more sensitive in identifying IOP changes in eyes with intraocular disease.


Assuntos
Pressão Intraocular , Rajidae , Animais , Cães , Tonometria Ocular/veterinária , Peso Corporal , Córnea
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