Laboratório de Dinâmica de Populações Marinhas (DIMAR)
Conservação de tubarões e raias do Brasil
O Laboratório de Dinâmica de Populações Marinhas (DIMAR) se localiza no Departamento de Pesca e Aquicultura da Universidade Federal Rural de Pernambuco e é coordenado pela Profa. Dra. Rosângela Lessa. Temos como objetivo principal compreender os processos biológicos dos elasmobrânquios (tubarões e raias) capturados na pesca direcionada e não-direcionada para guiar ações conservacionistas. Utilizamos uma combinação de abordagens e recursos tecnológicos que podem desenvolver resultados para diversos campos de estudo. Saiba mais sobre as nossas pesquisas e áreas de estudo abaixo.
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Referências e links para artigos
Connectivity between the marine coast and estuary for white mullet (Mugil curema) in northeastern Brazil revealed by otolith Sr:Ca ratio
Dezembro, 2018
Microchemical analyses were carried out in order to estimate the Strontium:Calcium (Sr:Ca) ratio in the otolith of the white mullet, Mugil curema, in the Pernambuco (at the Santa Cruz channel, Brazil) in order to determine its connectivity between the estuary and ocean. Variation in the otolith Sr:Ca ratio was directly related to salinity, with greater salinity denoting a higher otolith Sr:Ca value. Data on the otolith Sr:Ca ratio demonstrates that the individuals analyzed are born in areas of salinity that are characteristic of the estuary, where they develop until approximately one year of age, at which point they migrate to areas of greater salinity until reaching sexual maturity (3 years of age) in the sea. Spawning occurs in the ocean, after which M. curema individuals may either remain or return to the estuary until the next spawning. Differences in estuarine salinity were found for young-of-year individuals and may be related to the season when spawning took place, since M. curema females are found spawning throughout the year. The hypothesis is that higher salinity in the dry season leads to a greater otolith Sr:Ca signature among individuals spawned in this season from birth until one year of life. On the other hand, the lower salinity in the rainy season leads to a lower otolith Sr:Ca signature among individuals spawned in this season. These information are important for the adequate management of the white mullet stock in northeastern Brazil.
SANTANA, FRANCISCO M. ; MORIZE, ERIC ; LABONNE, MAYLIS ; LESSA, ROSANGELA ; CLAVIER, JACQUES . Connectivity between the marine coast and estuary for white mullet (Mugil curema) in northeastern Brazil revealed by otolith Sr:Ca ratio. ESTUARINE COASTAL AND SHELF SCIENCE , v. 215, p. 124-131, 2018.
Daggernose Shark: An Elusive Species from Northern South America
Novembro, 2018
The Daggernose Shark Isogomphodon oxyrhynchus is an endemic species of the northern coast of South America distributed from Trinidad and Tobago to Brazil's Amazon Coast. Due to increasing fishing efforts and its limited distribution range, the Daggernose Shark is one of the most endangered shark species in the world. Further threats arise from mangrove deforestation, pollution, and aquaculture caused by increasing human populations in coastal areas. The Daggernose Shark is highly associated to the turbid waters influenced by the Amazon and Orinoco estuaries. Furthermore, its morphological features associated to adaptations to these environments such as an elongated rostrum, small eyes, and long pectoral fins make it one of the most iconic shark species in the world. Finally, we report the capture of a young‐of‐the‐year I. oxyrhynchus in a freshwater system in Northern Brazil—the first recorded in a non‐marine environment.
FEITOSA, LEONARDO MANIR ; LESSA, ROSANGELA PAULA TEIXEIRA ; MARTINS, ANA PAULA BARBOSA ; BARBIERI, RICARDO ; NUNES, JORGE LUIZ SILVA . Daggernose Shark: an elusive species from Northern South America. FISHERIES , v. 2018, p. 1-6, 2018.
Age and growth of the endemic Xingu River stingray Potamotrygon leopoldi validated using fluorescent dyes
Abril, 2018
Between 2003 and 2005, vertebrae of 151 Xingu River Potamotrygon leopoldi (Potamotrygonidae) (75 males and 76 females) were analysed to derive a growth curve for this species. The disc width (WD) was significantly different between sexes, with females measuring 149–700 mm WD and males 109–500 mm WD. The average percentage error for vertebrae readings of the whole sample was 2·7%. The marginal increment ratio (RMI) showed an increasing trend with the highest value in November, decreasing from December on. The majority of vertebrae displaying RMI zero, occurred in September, but the annual periodicity of ring deposition throughout the year was not conclusive. Tetracycline (TCN) injected specimens were held in captivity for 13 months and displayed a fluorescent mark in vertebrae confirming a yearly periodicity of band pair formation with the translucent ring deposited in September–October. The Akaike information criterion (AIC) showed that, among the seven models considered, the best fit was obtained for the von Bertalanffy modified with W0 (where W0 = WD at birth) for both sexes. Growth parameters for females were: W0 = 149 mm; W∞ = 763·06 mm; k = 0·12 year– 1, whereas for males: W0 = 109 mm; W∞ = 536·4 and k = 0·22 year−1. Maximal ages were 7·2 years in males and 14·3 years in females. The species shows sexual dimorphism expressed in the growth pattern, size at maturity, longevity and asymptotic sizes. Concern for sustainability is raised due to the construction of the Belo Monte Hydroelectric Power Plant (2015 and 2016) in the State of Pará causing changes to the habitat of this species, which is endemic to the Xingu River and two of its tributaries.
Analysis of the supply chain and conservation status of sharks (Elasmobranchii: Superorder Selachimorpha) based on fisher knowledge
Março, 2018
Increasing fishing effort has caused declines in shark populations worldwide. Understanding biological and ecological characteristics of sharks is essential to effectively implement management measures, but to fully understand drivers of fishing pressure social factors must be considered through multidisciplinary and integrated approaches. The present study aimed to use fisher and trader knowledge to describe the shark catch and product supply chain in Northeastern Brazil, and evaluate perceptions regarding the regional conservation status of shark species. Non-systematic observations and structured individual interviews were conducted with experienced fishers and traders. The demand and economic value of shark fins has reportedly decreased over the last 10 years while the shark meat trade has increased slightly, including a small increase in the average price per kilogram of meat. Several threatened shark species were reportedly often captured off shore and traded at local markets. This reported and observed harvest breaches current Brazilian environmental laws. Fishing communities are aware of population declines of several shark species, but rarely take action to avoid capture of sharks. The continuing capture of sharks is mainly due to a lack of knowledge of environmental laws, lack of enforcement by responsible authorities, and difficulties encountered by fishers in finding alternative income streams. National and regional conservation measures are immediately required to reduce overfishing on shark populations in Northeastern Brazil. Social and economic improvements for poor fishing communities must also be implemented to achieve sustainable fisheries.
Rethinking use and trade of pelagic sharks from Brazil
Novembro, 2017
Brazil currently ranks as the 11th producer and 1st importer of shark meat around the world. Data available from the FAO software FishStatJ along with data from regional sources, such as governmental bulletins, scientific papers, gray literature and internet were revisited to identify the main issues surrounding pelagic shark fisheries, trade and consumption in the largest country in South America. Among the main findings, it was noted that Brazil has not properly collected fishery statistics since 2007, that many species of threatened sharks are freely landed and traded even though it is prohibited by local legislation and/or international recommendations (regional fisheries management organizations). The blue shark (Prionace glauca) is the most frequently recorded shark in the official bulletins and is currently a locally targeted species. Additionally, the significant imports of this species from 23 other countries that also provide fins for Asia has drawn attention in recent decades. Regarding consumption, shark is considered to be low-value seafood compared to more common fish, such as groupers and snappers, and most Brazilians actually do not know that they are eating sharks. At present, the proportion of threatened elasmobranchs (in which sharks are included) in Brazil (33%, of 145 species) exceeds the global rate identified for the group (25%), and, until the present moment, no measure related to the management of species has been implemented. As advice, Brazil urgently needs to restructure its fishery information collection systems, management strategies and to tighten sanitary and labeling regulations for the marketing of fish.
BARRETO, R.R. ; BORNATOWSKI, H. ; MOTTA, F.S. ; SANTANDER-NETO, J. ; VIANNA, G.M.S. ; LESSA, R. Rethinking use and trade of pelagic sharks from Brazil. MARINE POLICY , v. 85, p. 114-122, 2017.
Reproductive biology of Urotrygon microphthalmum (Batoidea: Urotrygonidae) from north-eastern Brazil, tropical west Atlantic Ocean
Março, 2016
The reproductive biology of Urotrygon microphthalmum was studied based on specimens caught as by‐catch in shrimp (Litopenaeus schmitti, Xiphopenaeus kroyeri, Farfantepenaeus subtilis and Farfantepenaeus brasiliensis) fishing operations between March 2010 and March 2012 on the coast of Pernambuco, Brazil. Females reached a larger total length (LT) and total body mass (MT) (298 mm and 148 g) than males (250 mm and 90 g). Length at maturity was estimated to be 188 and 199 mm LT for males and females. Uterine fecundity ranged from one to four embryos (mean ± s.d.: 1·85 ± 0·45). Size at birth was estimated to be 105 mm LT. Gestation lasted between 4 and 5 months. The reproductive cycle of U. microphthalmum is hypothesized to be asynchronous and biannual.
SANTANDER-NETO, J. ; ARAUJO, M. L. G. ; LESSA, R. P. T. . Reproductive biology of Urotrygon microphthalmum (Batoidea: Urotrygonidae) from north-eastern Brazil, tropical west Atlantic Ocean. Journal of Fish Biology , p. n/a-n/a, 2016.
Age, growth and mortality of white grunt caught in Pernambuco State, Brazil
Dezembro, 2018
The aim of the present study was to measure the primary growth parameters and to estimate the mortality of the white grunt Haemulon plumierii in the state of Pernambuco, Brazil. Sagittal otoliths were collected monthly from May 2013 to April 2014 from three different commercial fishing landings along the coast of Pernambuco. A total of 333 individuals measuring 10.5 to 32.2 cm total length were caught. The total length distributions were different between locations. The weight-length relationships and the von Bertalanffy equations were statistically different between the three fishing sites. The weight-length relationship indicated negative allometric growth, therefore the von Bertalanffy equation for pooled sexes was TLt = 31.1[1-e-0.1 (t +4.57)]. The maximum observed age was 21 years and the mortality rate was 0.21 year-1. The conducted analysis indicates a species with long life cycle and slow growth. Small reef fish with slow movement, such as the white grunt, are susceptible to fishing efforts, environmental factors and degradation, which affect growth and mortality. Therefore, we suggest an assessment of the status of the stock.
Diet of longnose stingray Hypanus guttatus (Myliobatiformes: Dasyatidae) in tropical coastal waters of Brazil
Novembro, 2019
This study investigated the diet of longnose stingray Hypanus guttatus in the tropical waters of north-eastern Brazil. Samples were obtained from monthly sampling of artisanal fisheries from August 2007 to July 2008. A total of 258 specimens were examined, 127 females and 131 males, and stomach contents analysis suggested H. guttatus to be a generalist and opportunistic predator feeding on the most available prey in the environment. There was no significant difference in the diet composition of males and females, or between seasons. However, an ontogenetic dietary shift was observed with larger individuals having an increased proportion of molluscs in the diet, whilst smaller individuals predated primarily on small crustaceans.
Dietary composition and trophic level of Hypanus marianae (Myliobatiformes: Dasyatidae), captured off Pernambuco coast, Brazil
Maio, 2019
Hypanus marianae, a stingray endemic to Brazil, inhabits coastal coral reef areas occurring in the landings of artisanal fisheries. The present study aimed to characterize the diet of this species captured off Pernambuco. We obtained 77 stomachs with contents: 52.27% female, 47.72% male. DW ranged from 15 to 37.80 cm mean of 26.53 ± 4.82 cm. Four higher taxonomic prey categories were identified: Arthropoda, Annelida, Chordata and Sipuncula. The most important item in the diet was Polychaeta (40.65% IRI), followed by Leptochela serratorbita (30.35% IRI), suborder Dendrobranchiata (10.18% IRI), order Isopoda (4.19% IRI), and Meiosquilla schmitti (3.56% IRI). H. marianae displays specialized predatory habit (BA = 0.06) primarily based on shrimps (42.36% IRI) and polychaetes (40.65% IRI). There was no significant difference in the diet by sex or in sexual development stages. However, neonates fed on decapods crustaceans (70.68%) and polychaetes (17.09%). For immatures, decapod crustaceans (69.5%) and polychaetes (25.86%) made up most of their diet. The adults feed mainly on polychaetes (62.79%) and crustacean decapods (30.47%), with a slight increase of fish (5.46%). The trophic level (TL) estimated was based on stomach content analysis was 3.66 and estimated on the analysis of stable isotopes being 3.29, which classified the species as a mesopredator.
Shape analysis of shark jaws as a tool to identify species involved in incidents with humans
Maio, 2019
Shark incidents in Recife, Pernambuco state (Brazil), are registered since 1992. The occurrence of those events is in a relatively small area of urban beaches of about 30 km long, making up one of the world's highest indices of shark incidents per unit of area, totaling 64 casualties, of these 24 were fatal. To mitigate shark incidents, the knowledge on shark species involved is crucial given that each species has specific usage of the habitat and dissimilar feeding strategy. Jaws of five species caught along the Pernambuco coast (Brazil), corresponded to 2 specimens of Carcharhinus acronotus, 4 specimens of C. leucas, 1 of C. limbatus, 4 of Galeocerdo curvier and 3 of Sphyrna lewini. Relative Warps Analysis was applied to enhance possible differences among jaw shapes of the studied species. The consensus configuration from the 14 images was obtained. The first two relative warps components explained 70.17% of the total observed variation. Four distinct groups were clearly observed. Three groups were formed by single species, corresponding to G. curvier, C. leucas and S. lewini, respectively, and one group formed by the combination of C. acronotus and C. limbatus. As expected, due to its peculiar skull shape, S. lewini jaws are very different from other analyzed species, thus all observed individuals of this group were found isolated from the others, considering the horizontal axis. Relative warps and curvature analyses show to be useful tools in the forensic study of shark incidents. In general, jaws shape significantly differed among species.
Occurrence of brephoepipelagic fishes in the stomach contents of large pelagic predators in the southwestern equatorial Atlantic Ocean
Junho, 2019
The brephoepipelagic fishes are characterized by having larvae and juveniles that live in the pelagic environment and displace to the bottom in coastal water when adults. In the oceanic region of northeastern Brazil their presence was studied as part of the diet of 1,990 stomachs analyzed from 15 large predators, with the presence of 3,562 individuals of brephoepipelagic fishes. Seven species, with a higher dominance of Dactylopterus volitans (87.7% in number) were found, followed by other genera and species, Balistes sp. (4.35%), Diodon sp. (3.43%), Acanthurus sp. (1.88%), Holocentrus adscensionis (1.54%), Acanthostracion sp.(0.87%), Fistularia sp. (0.34%), and Monacanthus sp. (0.25%). Their main predators were the dolphinfish (Coryphaena hippurus), tunas (Thunnus spp.), and billfishes (Istiophoridae). The presence and abundance in the open ocean may have origin from islands and oceanic banks in the northeast region, also along the coast, where they disperse to open waters due to currents and eddies, becoming available for large predators between at a size between 2 and 14 cm.
Age structure and multi-model growth estimation of longnose stingray Hypanus guttatus (Dasyatidae: Myliobatoidei) from north-east Brazil
Janeiro, 2019
We collected 729 Hypanus guttatus from the northern coast of the state of Rio Grande do Norte (RN), of which 196 were used to estimate age and growth. Ninety-five were male (12.7 to 57.0 cm disc width; WD) and 101 were female (13.0 to 88.5 cm WD); females were significantly larger than males. Cross sections of vertebrae showed band-pairs ranging from 0 to > 14 in females and from 0 to 9 in males. New-borns presented an opaque edge at birth in vertebrae without a birthmark. The average percentage of error (APE; %E) for the entire sample provided evidence that ages were repeatable. The mean monthly marginal increment (IM) indicates annual band-pair formation from August to November. The annual cycle model for one band-pair deposition provided the best fit to data based on the AIC, with peaks between August and October, similar to that found in the IM analysis, suggesting an annual formation pattern. A multi-model approach that included four models based on the observed mean WD at age indicated a modified von Bertalanffy growth model as the best for describing the species growth: W0 (WD at birth) = 14.6 cm for both sexes; females W∞ = 98.61 cm (95% CI = 87.34–114.61 cm); k = 0.112 year−1 (CI = 0.086–0.148 year−1); males W∞ = 60.22 cm (CI = 55.66–65.35 cm); k = 0.219 year−1 (CI = 0.185–0.276 year−1). The age-at-maturity in males and females is 5 years and 7 years, respectively. The age composition shows that most (84%) specimens were aged 0 to 2 years. The information provided here is essential for analytical assessments of H. guttatus, which is subject to significant fishing pressure mainly on new-borns and juveniles.
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