Rhizoprionodon Lalandii Research Articles

First report on metal and metalloid contamination of Ampullae of Lorenzini in sharks: A case study employing the Brazilian sharpnose shark Rhizoprionodon lalandii from Southeastern Brazil as an ecotoxicological model

Metal contamination has never been assessed in Ampullae of Lorenzini. This study employed Rhizoprionodon lalandii, as an ecotoxicological model to investigate potential metal accumulation in Ampullae of Lorenzini jelly. No differences between sexes were observed regarding jelly metal concentrations at Rio das Ostras (RJ) or Santos (SP). Statistically significant correlations were noted between total lengths (TL) and condition factors and several metals at both sampling sites, demonstrating the potential for Chondrichthyan sensory capacity disruption and possible effects on foraging success. Maternal metal transfer to Ampullae jelly was confirmed. Rhizoprionodon lalandii is thus, a good model to assess Ampullae of Lorenzini contamination, as this electrosensory organ seems to be highly vulnerable to metal contamination.

A shot in the dark for conservation: Evidence of illegal commerce in endemic and threatened species of elasmobranch at a public fish market in southern Brazil

Abstract The illegal sale of endangered elasmobranchs has been recorded in a number of different Brazilian states, where sharks and rays are being marketed primarily as ‘cação’ or ‘viola’. Brazil is ranked among the top 10 nations worldwide that harvest most sharks, causing an immeasurable impact on the local elasmobranch populations. The present study applied the DNA barcoding technique, based on the cytochrome C oxidase subunit I gene, for the molecular identification of the elasmobranch species sold as processed products under the generic names of ‘cação’, ‘mangona’, ‘azul’, ‘cambeva’, ‘fiuso’ and ‘lombo preto’, in the fish market of the city of Florianópolis, capital of the state of Santa Catarina, Brazil. Nine elasmobranch species were identified in the 56 samples analysed, including six sharks and three rays, representing six families, the Carcharhinidae, Sphyrnidae, Squatinidae, Arhynchobatidae, Myliobatidae and Gymnuridae. Prionace glauca, identified in more than half (56%) of the samples analysed, is listed as Near Threatened by the International Union for the Conservation of Nature. Six species identified in the present study, Sphyrna zygaena, Sphyrna lewini, Squatina guggenheim, Carcharhinus signatus, Gymnura altavela and Rioraja agassizii, are under some level of risk of extinction, while two others (Rhizoprionodon lalandii and Myliobatis goodei) are listed as Data Deficient. Our results indicate that the commercial exploitation of endemic sharks and rays at risk of extinction is commonplace in southern Brazil. This reinforces the need for more systematic monitoring of the trade in fishery products and more effective application of the environmental legislation and conservation programmes.

Mercury screening in highly consumed sharpnose sharks (Rhizoprionodon lalandii and R. porosus) caught artisanally in southeastern Brazil

Sharpnose sharks Rhizoprionodon lalandii and R. porosus are frequently captured in fishing activities in Brazil and are significantly consumed by humans, especially in southeastern Brazil. Both species lack population data and suffer intense fishing pressures and habitat degradation, consequently hindering adequate management and conservation actions. In this context, this study aimed to assess mercury (Hg) contamination in R. lalandii, and R. porosus sampled off the coast of Rio de Janeiro, addressing both animal health and public health risks. Sharks were obtained from two artisanal fishing colonies in southeastern Brazil (Copacabana and Recreio dos Bandeirantes), located on the coastal zone adjacent to Guanabara Bay, one of the most important, productive, and contaminated estuaries in Brazil, and a further three artisanal fishing colonies from the Região dos Lagos area (Saquarema, Cabo Frio and Rio das Ostras). Hg concentrations in liver, muscle, and brain in R. lalandii (n = 24) and R. porosus (n = 20) specimens were determined by inductively coupled plasma mass spectrometry. A gravid female measuring 112 cm from Copacabana is the first record for an individual of this size for R. lalandii. No correlation between length and muscle Hg concentrations was observed, and no differences between Hg concentrations for muscle or liver were found between male and female juveniles from either Cabo Frio or Rio das Ostras. No differences in Hg loads were observed herein for both assessed species. Low Hg bioaccumulation in juveniles and nongravid female muscle tissue was noted compared to significantly higher Hg concentrations in gravid females. Hg was detected in all embryos, indicating potential maternal offloading. As Hg thresholds for sharks in particular have not yet been established, whether the Hg concentrations detected in brain pose neurotoxic risks for these animals is not known. Public health concerns concerning adult R. lalandii consumption from Copacabana, however, are significant.

Age and growth of two sharpnose shark species (Rhizoprionodon lalandii and R. porosus) in subtropical waters of the south-western Atlantic

The age and growth of subtropical populations of the Brazilian and Caribbean sharpnose sharks (Rhizoprionodon lalandii and R. porosus respectively) were determined by combining direct and indirect ageing methods, maximising the use of available information. Using vertebrae ageing for R. lalandii, the theoretical maximum length L∞ and growth coefficient k were 661.9mm and 1.14 year–1 for males and 751.7mm and 0.59 year–1 for females. Vertebrae were not sampled for R. porosus. Values of L∞ and k from electronic length–frequency analyses (ELEFAN) were 762mm and 0.71 year–1 for male R. lalandii, 791mm and 0.67 year–1 for female R. lalandii, 1040mm and 0.41 year–1 for male R. porosus and 1165mm and 0.31 year–1 for female R. porosus. Growth during the first year of life in relation to birth size was 80.3% for R. lalandii and 55% for R. porosus. Both species exhibit rapid growth, primarily in the first year of life. The growth estimates for R. lalandii and R. porosus are even faster than those reported in previous studies from tropical populations.

TUBARÕES E RAIAS COMO CAPTURA INCIDENTAL NA PESCA ARTESANAL DO LITORAL DO PARANÁ: CONDIÇÃO REPRODUTIVA E VARIAÇÕES SAZONAIS EM COMPOSIÇÃO E ABUNDÂNCIA

Monitoraram-se os desembarques de elasmobrânquios no litoral do Paraná nos anos 2009 e 2010. Descrevem-se atributos de frota e petrechos empregados. As espécies foram caracterizadas quanto ao tamanho dos indivíduos e à condição reprodutiva. Acessaram-se 4.941 indivíduos, 51% tubarões e 49% raias. Foram desembarcados inteiros 82% dos indivíduos, 3,68 t de tubarões e 2,35 t de raias. Identificaram-se 14 espécies de tubarões, peso médio de 1,46 kg (0,067-16,0 kg; DP = 3,83), predominando em número Rhizoprionodon lalandii e Sphyrna zygaena. Os tubarões foram mais capturados na primavera/verão, com maior frequência de neonatos ou imaturos. Registraram-se 12 espécies de raias, peso médio de 0,971 kg (0,394-10,0 kg; DP = 2,80), predominando em número Zapteryx brevirostris e Pseudobatos percellens. As raias foram mais capturadas no outono, em pescarias dirigidas a camarões e pequenos teleósteos, com maior frequência de imaturas ou maduras. Onze das 26 espécies são classificadas como vulneráveis, em perigo ou criticamente ameaçadas. Para fins de conservação, recomendam-se ações educativas pró-descarte de: animais vivos – neonatos em geral, Narcine brasiliensis no arrasto camaroeiro, e jovens e adultos de espécies com captura proibida; e priorização à proteção de Carcharias taurus, P. percellens acompanhante da pesca de linguado, e jovens de Squatina sp., cujos adultos são alvo em redes de emalhe.
 Palavras-chave: reprodução, neonatos, arrasto, captura incidental, Rhizoprionodon lalandii, Sphyrna zygaena, Zapteryx brevirostris.

Condition analysis of the Brazilian sharpnose shark Rhizoprionodon lalandii: evidence of maternal investment for initial post-natal life.

The present study analysed the condition factor (K) and the hepato-somatic index (I H ) of the Brazilian sharpnose shark Rhizoprionodon lalandii during its entire life cycle. Discontinuity of liver growth was observed after sexual maturity. High condition values were recorded in the length classes of 300-350 mm (neonates), when the livers represented about 8% of total mass, decreasing until the length classes of 400-450 and 450-500 mm in females and males, respectively. Seasonal analysis exhibited low I H values in the summer, while for K, low values were in spring, indicating greater investment for body growth during spring and for gonad maturation in summer. Such findings indicate that this small coastal shark species accumulates reserve substances in the liver that will be used during reproduction. The decline in I H values in juveniles suggests that reserves provisioned by the mother to the neonate liver can be used in the first months of life.

Length - length relationships of 16 Caribbean elasmobranchs

Elasmobranchs are commonly landed without fins and heads; however, the knowledge of total length is necessary for fishery management. We provide useful equations to extrapolate partial from elasmobranch carcasses lengths, to total lengths. Length-Length Relationships (LLR) are described for 16 commercial elasmobranch species all included in the IUCN Red List: Hexanchus nakamurai, Heptranchias perlo, Squalus cubensis, Squatina dumeril, Scyliorhinus boa, Mustelus minicanis, M. higmani, M. norrisi, Carcharhinus acronotus, C. falciformis, C. limbatus, Galeocerdo cuvier, Rhizoprionodon lalandii, R. porosus, Sphyrna lewini and Pseudobatos percellens. This study provide new LLR equations and rsepresent an improvement in the knowledge of these species.

Gross chemical profile and calculation of nitrogen-to-protein conversion factors for nine species of fishes from coastal waters of Brazil

The amino acid composition and contents of nitrogen, phosphorus, lipid, carbohydrate and protein were determined in muscles of Dactylopterus volitans, Genypterus brasiliensis, Mullus argentinae, Paralichthys patagonicus, Percophis brasiliensis, Pinguipes brasilianus, Rhizoprionodon lalandii, Rhizoprionodon porosus, and Urophycis cirrata. The samples showed low carbohydrate content (<3.5% dry weight in all species) and were rich in protein (>66% dry weight in all species). The percentage of total lipid varied widely among species, and M. argentinae showed the highest concentrations (16%). The percentage of nitrogen and phosphorus was high and similar among species, with overall average values of 13.3% and 1.2%, respectively. The amino acids composition was similar among the animals, with glutamic acid and lisine as the most abundant amino acid and histidine in low concentrations. Among species, the content of proteinaceous nitrogen was high, with an average of 96.8% of the total nitrogen. From data of total amino acid and total nitrogen, specific nitrogen-to-protein conversion factors were calculated for each species. The nitrogen-toprotein conversion factors ranged from 5.39 to 5.98, with an overall average of 5.71. These findings showed that the traditional conversion factor of 6.25 overestimates the actual protein content and should be avoided.

Microscopic aspects of the nictitating membrane in Carcharhinidae and Sphyrnidae sharks: a preliminary study

The nictitating membrane is an anatomic structure exclusively exhibited by Carcharhiniformes, the largest order among sharks. Here we present a detailed description of morphological characteristics of the nictitating membrane through light microscopy (LM) and scanning electron microscopy (SEM) in the following shark species: Carcharhinus limbatus, Galeocerdo cuvier, Prionace glauca, Rhizoprionodon lalandii, R. porosus, Sphyrna lewini and S. zygaena. Differences in the microscopic aspects of dermal denticles from the species studied were observed. P. glauca, a pelagic shark, showed a well-developed protection apparatus when compared with other pelagic species, while coastal sharks showed even higher structural complexity. In the blue shark the denticles are enameled, presenting an extensive pulp cavity and a base inserted in a connective tissue. Moreover, the species exhibits the higher number of ridges (up to nine) of varied size and shape and the muscular tissue is inserted in the ventral region of the connective tissue. Dermal denticles from C. limbatus, R. lalandii, R. porosus, S. zygaena and G. cuvier exhibit up to five ridges with hexagonal ornamentations in the crown. In S. lewini and S. zygaena, the denticles are rounded shaped and glandular cells are present. The patterns observed in the present study suggest a high level of specialization and evolutionary conservation shaped by the function of the structure. In addition, we hypothesize that the morphological simplification observed in the membrane when compared to the dermal denticles from the skin, is an evolutionary trait that evolved to improve the dynamic and biomechanics of this highly mobile structure allowing this way, a rapid and efficient protection against abrasion, mainly during predation events.

Feeding ecology of elasmobranch species in southeastern Brazil

ABSTRACT The feeding ecology of five elasmobranch species was studied on the southern coast of Rio de Janeiro, southwestern Atlantic Ocean. The specimens were caught with a trawl or bottom longline between January 2006 and August 2007. The diets of Psammobatis rutrum and Psammobatis extenta appeared to be basically carcino-benthophagous, with a very small niche width. Rioraja agassizii was basically carcino/ichthyo-benthophagous, also with a narrow niche, including teleost fish and shrimp, but in different proportions according to age and sex. Rhizoprionodon lalandii was ichthyophagous, not influenced by age or sex. The analyses of these species and Atlantoraja cyclophora indicated two trophic groups: one composed of the smaller rays, P. extenta and P. rutrum, which basically fed on small crustaceans, polychaetes and nematodes; and the other of R. lalandii and the larger rays R. agassizii and A. cyclophora, which preyed on teleost fish and brachyurans.

Comparison of the Morphology and Histomorphometry of Spermatogenic Cyst of Three Sharks Species With Diametric Testes.

Characterization of the reproductive anatomy of elasmobranchs (sharks, skates, rays, and sawfish) offers unique insights into the evolution of reproductive traits in animals due to their phylogenetic position at the base of the vertebrate tree of life. Yet, despite advances in our understanding of male elasmobranch reproductive physiology and testes histology, very little is known about how testes histomorphometrics varies with male maturation. In this study, we characterize and contrast testes morphology and histomorphology of males at different maturation stages in three shark species with diametric testes development: Prionaceglauca, Rhizoprionodon lalandii, and Mustelus canis. All stages of spermatogenesis were observed in P. glauca and R. lalandii, while for M. canis, only males at early stages of maturation were examined and therefore all the spermatogenesis cells lineage were not present. The number of Sertoli cells increased with cell development by six times in R. lalandii and roughly four times in P. glauca, and were statistically different among stages of spermatogenesis cysts in both species. Statistical differences in cyst diameter and Sertoli cell numbers were observed between P. glauca and R. lalandii. The increase of spermatocyte II cell diameter described for R. Lalandii in this study was not usual to elasmobranch species as compared, for example, to P. glauca. This information proves the importance of studying the testicular development and the process of spermatogenesis is necessary for understanding the reproductive biology of the species, including life cycles and history, variation of reproductive morphology. Anat Rec, 299:759-768, 2016. © 2016 Wiley Periodicals, Inc.

Are we eating plastic-ingesting fish?

Yes, we are eating plastic-ingesting fish. A baseline assessment of plastic pellet ingestion by two species of important edible fish caught along the eastern coast of Brazil is described. The rate of plastic ingestion by king mackerel (Scomberomorus cavalla) was quite high (62.5%), followed by the Brazilian sharpnose shark (Rhizoprionodon lalandii, 33%). From 2 to 6 plastic resin pellets were encountered in the stomachs of each fish, with sizes of from 1 to 5 mm, and with colors ranging from clear to white and yellowish. Ecological and health-related implications are discussed and the potential for transferring these materials through the food-chain are addressed. Further research will be needed of other species harvested for human consumption.

Ultrastructure of dermal denticles in sharpnose shark (Rhizoprionodon lalandii) (Elasmobranchii, Carcharhinidae).

The presence of denticles in the external surface, oral cavity, fins, and clasper of Elasmobranchii has been widely reported. These structures, called body denticles, may be observed on the body surface of sharks. Dermal and oral denticles are made up by a basal plate that is embedded in the dermis, forming a peduncle that grows from the base to the crown. These denticles may protect the skin against abrasion, and improve hydrodynamics and gill arches function. Rhizoprionodon lalandii is a widely distributed and very common species in Brazilian coastal areas. The aims of this study was to compare the morphology of oral and body denticles of R. lalandii to understand the implications of these structures in the behavior of these animals. Morphological analysis showed that there are differences between dermal and oral denticles, which are related to their role in different body regions. Body denticles have three cusps, and well-defined crests and ridges, and literature data suggest that suggest that hydrodynamics is their main function. Most of the oral denticles have only one cusp, and their morphology and distribution showed that their main functions are preparing food to be swallowed and protecting the oral cavity against abrasion.

Persistent organic pollutants in liver of Brazilian sharpnose shark (Rhizoprionodon lalandii) from southeastern coast of Brazil

In the present study, persistent organic pollutants (POPs) were determined in 14 livers from specimens of the Brazilian sharpnose shark (Rhizoprionodon lalandii), which is an important economic resource for small-scale fisheries on the southeastern coast of Brazil. The following concentrations (lipid weight) of POPs were found: ∑PCBs: 1019±267ngg−1; ∑DDTs: 111±40ngg−1 and ∑PBDEs: 10.4±4.78. PCB 153 made the greatest contribution to ∑PCB (21.4%), followed by PCB 138 (14.6%) and PCB 180 (9.94%). Among chlorinated pesticides, only the p,p′-DDE and p,p′-DDD isomers had concentrations above the detection limit. Moreover, levels above the detection limit were found only for PBDE congeners 47 and 100 (BDEs 47>99). On average, BDE 47 accounted for 88% of the total PBDE load. The feeding habits of the Brazilian sharpnose shark close to the Brazilian coastline are likely the most important difference regarding the accumulation of POPs in comparison to oceanic species that feed in deeper waters. Thus, this species may be used to evaluate the pollution of coastal areas as well as human exposure to contaminants, as the Brazilian sharpnose shark is a frequently used for human consumption. Further studies in other areas of Brazil and involving other species are needed to clarify the mechanisms and potential impact of POPs, which can affect the biology of different organisms and cause population declines.

Abnormal embryos of sharpnose sharks, Rhizoprionodon porosus and Rhizoprionodon lalandii (Elasmobranchii: Carcharhinidae), from Brazilian coast, western South Atlantic

This study presents the second worldwide report on abnormal embryos of the sharpnose sharks, Rhizoprionodon, based on the two species (Rhizoprionodon porosus and Rhizoprionodon lalandii) occurring on the Brazilian coast. For R. porosus two conjoined twin embryos showing complete duplication of the vertebral column, viscera and several external structures (head, first and second dorsal fins, pectoral fins), and scoliosis in both axis at the pelvic fin level are reported. The three embryos of R. lalandii exhibited numerous lordosis and kyphosis along the entire vertebral column. The possible relationship between anomalies and the human major threats to sharks is discussed based on previous reproductive, genetic and ecotoxicological studies on R. lalandii for southern Brazil.

Diversity and genetic population structure of the Brazilian sharpnose shark Rhizoprionodon lalandii

ABSTRACT Similar to many small, range‐restricted elasmobranchs, the Brazilian sharpnose shark (Rhizoprionodon lalandii) is listed as ‘data deficient’ by the International Union for the Conservation of Nature (IUCN). Data on stock assessment and sustainability are scarce, and there is no information on population structure. This constitutes a management problem because this shark comprises approximately 50% of the catch of small coastal sharks in Brazil. In this study, populations of R. lalandii distributed from the Caribbean to southern Brazil were investigated using sequences from the mitochondrial DNA control region. Analysis of molecular variance revealed strong structuring between population samples from the Caribbean and those from the Brazilian coast (ФST = 0.254, P < 0.0001). Significant differences in the rates of genetic diversity between these major areas were also detected. The observed levels of population structuring are likely to be driven by female phylopatry. Therefore, the identification of both mating and nursery areas with parallel ban/restriction of fishing in these areas may be critical for the long‐term sustainability of these populations. Copyright © 2013 John Wiley & Sons, Ltd.

Latitudinal disparity in the reproductive cycle of sharpnose shark, Rhizoprionodon lalandii (Elasmobranchii: Carcharhinidae), in Atlantic waters off South America

Geographical variation in biophysical conditions may strongly influence the life history characteristics of widely distributed species, such as the Brazilian sharpnose shark, Rhizoprionodon lalandii (Müller & Henle, 1839). Here, we use original and secondary data of reproductive traits of R. lalandii to identify population differences among northern/northeastern and southern Atlantic waters of South America. In the southeast region, birth occurs between December and March, and the young become frequent along the coast between April and September. Mating occurs mainly between March and June, when females with bite marks are common. Females in early pregnancy occur between March and September. The reproductive cycle of R. lalandii in the northern/northeastern region was approximately six months ahead of the cycle described for the southeastern region. These results support the hypothesis that environmental conditions in the North-Northeast and Southeast generate differences in life history traits, resulting in at least two distinct populations along the Brazilian coast.

Feeding of the Brazilian sharpnose shark Rhizoprionodon lalandii (Müller & Henle, 1839) from southern Brazil

Summary Stomach contents of 175 Brazilian sharpnose sharks, Rhizoprionodon lalandii, were examined to assess their feeding habits. Caught by artisanal fishers between June 2006 and July of 2007 at Ipanema Beach, on the central coast of the state of Parana, southern Brazil, R. lalandii appears to be piscivorous (89.7% IRI), feeding mainly on families of Clupeidae (5.1% IRI) and Sciaenidae (3.7% IRI) and secondarily on squid Lolliguncula brevis (8.6% IRI). Diets were similar between sexes and seasons. However, there were ontogenetic changes in their diets. The major items for neonates were Penaeidae crustaceans (%IRI = 56.4) and Engraulidae fishes (%IRI = 29.3); for the juveniles, Sciaenidae (%IRI = 62.5) and Clupeidae (%IRI = 19.7), and for adults Clupeidae (%IRI = 45.8) and Sciaenidae (%IRI = 15.9). Only neonate sharks consumed crustaceans, whereas all size classes consumed cephalopods and teleosts. Neonates had the lowest trophic level (TR = 3.8), with the diet of juveniles and adults the highest (TR = 4.2). Given its abundance and diet, R. lalandii may be an important predator of demersal and pelagic prey in coastal waters of Brazil.

ASPECTOS DA ALIMENTAÇÃO NATURAL DO CAÇÃOFRANGO Rhizoprionodon lalandii (VALENCIENNES,1841) (ELASMOBRANCHII, CARCHARHINIDAE) NO MUNICÍPIO DE BARRA VELHA, SANTA CATARINA.

The brazilian sharpnose shark Rhizoprionodon lalandii (Valenciennes,1841) occurs in the east coast of South America, from Panama to Santa Catarina. The present work studied some aspects of the feeding behavior of R. lalandii. Samples were collected monthly, between September 1999 and June 2000 being captured by artisanal fleet. The alimentary items were identified to the lowest taxonomic level possible. The occurrence percentage of the items was obtained through the equation: n.o of stomachs that contained the item / n.o of stomachs that contained food x 100. From the 78 examined stomachs, 61 (78%) contained food. The predominant items in the stomachs were Teleostei, representing 47% of the total of items followed by Molusca: Cephalopoda (26%). Most of the bony fishes found in the stomachs content were Clupeiformes and all Cephalopoda represented by the suborder Myopsida. The largest repletion GR 4, most of the individuals presented stomachs filled less than GR 2 and GR 1, and some had empty stomachs (22%). R. lalandii, feeds mainly on pelagic species specially small bony fishes and squids. As the diversity of preys was small, it is supposed that R. lalandii is a selective predator.

Populations analysis of the Brazilian Sharpnose Shark Rhizoprionodon lalandii (Chondrichthyes: Carcharhinidae) on the São Paulo coast, Southern Brazil: inferences from mt DNA sequences

Sharks of the genus Rhizoprionodon can be considered some of the most important predators along the trophic coastal marine ecosystems and represent an important economic resource for the small-scale fisheries, especially on the Brazilian coastline. In order to analyze the population structure of the shark Rhizoprionodon lalandii of São Paulo, Southeastern coast of Brazil, levels of genetic diversity were identified by nucleotide sequence analyses of the mitochondrial DNA control region. The results obtained from this study present moderate values of haplotype diversity and low nucleotide diversity. Although the AMOVA tests (ΦST = 0.08394, P < 0.01) had shown slightly differences among the studied samples, evidence for the occurrence of population structuring was not found, which may be a general feature of sharks living in coastal areas.