NEOTROPICAL FRESHWATER FISHES: A dataset of occurrence and abundance of freshwater fishes in the Neotropics

The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large-scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications.

Feeding habits of Urotrygon microphthalmum (Myliobatiformes: Urotrygonidae) caught off northeastern Brazil

Abstract The feeding habits of Urotrygon microphthalmum, a Critically Endangered (CR) species, were investigated through stomach contents analysis from specimens caught on bottom double rigged otter trawls in Pernambuco state, Brazil, between March of 2010 and March of 2012. A total of 338 stomachs were analyzed, and 31 food items were identified in the diet of U. microphthalmum. The species ingests mainly shrimps. The diets between males and females were not different, and an ontogenetic diet shift was not observed. The estimated species’ trophic level is 3.5, classifying it as a secondary order consumer.

Ichthyofauna of the inner shelf of Paraná, Brazil: checklist, geographic distribution, economic importance and conservation status

Abstract Comprehensive species checklists are essential to effectively implementing preservation and recovery measures, and should assess conservation status, vulnerability degree and anthropogenic threats. This checklist was compiled from fish species recorded in surveys conducted over the last 30 years in the shallow inner continental shelf in the State of Paraná, Brazil. Information on biogeography, conservation status, economic importance and degree of species’ vulnerability are provided. A total of 272 fish species were recorded, spanning 25 orders and 88 families. The most speciose family was Sciaenidae (25 species), followed by Carangidae (23), Engraulidae (10), Carcharhinidae (9), Epinephelidae (9) and Paralichthyidae (9). Most species occurring in Paraná’s shallow inner continental shelf are restricted to the West Atlantic. In terms of economic importance, 93% (253) of the species recorded were of fishery, aquaculture or aquaria interest. A notable fraction (39%) of the recorded species was classified as having moderate to very high vulnerability to extinction. In particular, 28 species (10%) were listed as globally endangered, and 34 species (12%) were listed as endangered in the Brazilian territory.

Human introduction or natural dispersion? Atlantic Ocean occurrence of the Indo-Pacific whitetip reef shark Triaenodon obesus

Occurrence of multiple whitetip reef sharks Triaenodon obesus in the Atlantic Ocean is reported for the first time from near a sunken ferry off the Paraná coast in south-eastern Brazil. This occurrence is hypothesized to have been caused by either a human introduction or a remarkably long oceanic displacement.

Interactions between Manta birostris and Sotalia guianensis in a World Heritage listed Brazilian estuary

During 1442 h of visual observations over 7 years throughout the World Heritage listed Paranaguá estuarine complex, Brazil, seven occurrences of interactions were observed at a single location involving breaching Manta birostris displacing schools of teleosts, which were subsequently preyed upon by Sotalia guianensis. Although the interactions were not definitively categorized as being amensal, commensal or mutual, their restriction to isolated space (adjacent to a protected area) and time (summer) supports previous assertions the area is important to regional productivity and the continuation of protected-area status.

Talking to the dead: using Post-mortem data in the assessment of stress in tiger sharks (Galeocerdo cuvier) (Péron and Lesueur, 1822)

Sharks are very sensitive to stress and prone to a high mortality rate after capture. Since approximately 50 million of sharks are caught as bycatch every year, and current recommendations to reduce the impact of commercial fishing strongly support immediate release, it is imperative to better understand post-release mortality caused by the stress of capture and handling. Blood samples allow the assessment of stress levels which are valuable tools to reduce mortality in commercial, recreational and scientific fishing, being essential for the improvement in those conservation measures. Biochemical analyses are widely used for sharks as stress indicators, with secondary plasma parameters (lactate, glucose and ions) being the most often employed assays. However, it is virtually impossible to determine baseline plasma parameters in free-ranging sharks, since blood withdrawal involves animal capture and restrain, which are stressful procedures. This study aims at analyzing secondary parameters of five healthy tiger sharks captured with circular hooks and handlines in Fernando de Noronha (Northeastern Brazil) and comparing them with secondary parameters of three dead tiger sharks caught off Recife (also Northeastern Brazil). The results showed that the analysis of some plasma constituents in dead animals may be an efficient tool to assess stress and lethality. However, traditional parameters such as glucose and calcium, need to be used with caution. The results also demonstrated the extreme importance of urea and phosphorus for assessing stress response and mortality in tiger sharks, both parameters frequently neglected and of utmost importance for shark's homeostasis.

Fishers' ecological knowledge of smalleye hammerhead, Sphyrna tudes , in a tropical estuary

ABSTRACT Coastal hammerheads have suffered from overexploitation and environmental degradation. We interviewed 79 artisanal fishers to verify fishery aspects, temporal changes in catches and biological aspects of the smalleye hammerhead, Sphyrna tudes , in a marine protected area on Abrolhos Bank, Brazil. Data were compared between three generations of fishers: young, middle-aged and old. Fishers' age varied between 17 and 88 years. We verified significant reductions in the weight of individuals caught by younger fishers. The main types of fishing gear used to catch S. tudes were gill nets and longlines. Overfishing through gill nets and trawl fisheries were mentioned as the cause of S. tudes population collapse in the region. The shark's diet as reported by fishers consisted of fish, crab and shrimp; austral summer was the reproductive season. A strong similarity was verified between fishers' knowledge and biological data. We suggest as plausible strategies to conserve the local population of S. tudes the reduction of net fisheries impact through zoning and establishment of no take areas. These steps can help to initiate the recovery of this depleted species.

“Buying a Pig in a Poke”: The Problem of Elasmobranch Meat Consumption in Southern Brazil

In Brazil, the demand for sustainably certified seafood is increasing and retailers have promised to source all seafood from sustainable sources by 2015. In the southern portion of the country, elasmobranch meat is sold as cação, and consumers are often unaware that cação refers to any type of elasmobranch. The present study used questionnaires to investigate the lay public’s knowledge of elasmobranch meat sold in a Brazilian city. Shoppers were surveyed at supermarkets in Curitiba, the largest city in southern Brazil. The study revealed that people do not link commercialized cação meat to sharks and rays (Elasmobranchii), with more than half of respondents who claimed to have already eaten cação did not think they had ever eaten shark or ray. The educational profile of interviewees suggests that this lack of knowledge may be even more common in other segments of Brazilian society. Therefore, we suggest that ecological information about elasmobranchs should be included in Brazilian elementary and high school curricula. Such a measure has the potential to modify behavior, create awareness, and stimulate responsibility throughout society, with the primary goal of reducing shark meat consumption and, ultimately, guaranteeing the long term conservation of marine resources.

Diet of the chola guitarfish, Rhinobatos percellens (Rhinobatidae), in the Paranaguá Estuarine complex

The chola guitarfish, Rhinobatos percellens, is one of the most-captured batoids on the Brazilian coast, and an important predator of benthic community. Stomachs from R. percellens were sampled in the Paranaguá estuarine complex (March/2006 to March/2007 and October/2008 to September/2009). The stomachs obtained were used for describing the diet of R. percellens, and verifying if there are seasonal and ontogenetic differences in their feeding into the estuarine area. The general analysis showed a specialized diet with a predominance of three species in food contents: Leptochela serratorbita, Caridea remains and Ogyrides alphaerostris. Ontogenetic and seasonal analysis did not reveal significant differences in the food consumption. These data reveal that R. percellens is a specialist predator of L. serratorbita, and this food component is consumed by all size classes.

Feeding ecology and trophic comparisons of six shark species in a coastal ecosystem off southern Brazil

The diets of six shark species, Sphyrna lewini, Sphyrna zygaena, Carcharhinus obscurus, Carcharhinus limbatus, Rhizoprionodon lalandii and Galeocerdo cuvier, were investigated in a subtropical coastal ecosystem of southern Brazil. Stomach content data were obtained to assess foraging niche segregation and ontogenetic shifts in the diets of these sharks. Five of the shark species off the Paraná coast were ichthyophagous, with the exception of S. zygaena, which was teutophagous. With the exception of G. cuvier, which had a generalist diet, the other five species displayed specialization in their feeding. Ontogenetic shifts were observed in C. obscurus and S. lewini with large individuals consuming elasmobranchs. Owing to the diet overlap between C. obscurus and S. lewini, C. obscurus and C. limbatus and R. lalandii and C. limbatus, future studies on the spatial and temporal distributions of these species are needed to understand the extent of competitive interactions.

Shark scavenging and predation on sea turtles in northeastern Brazil

Large sharks have the potential to help structure ecosystem dynamics through top-down impacts on their prey, including sea turtles. Studies of interactions between large sharks and sea turtles, however, are practically nonexistent along the Brazilian coast. Between September 2002 and May 2011 we examined 655 sea turtles – including green turtles Chelonia mydas (n = 607), olive ridleys Lepidochelys olivacea (n = 10), hawksbills Eretmochelys imbricata (n = 33), and loggerheads Caretta caretta (n = 5) – that stranded on Paraíba coast, northeastern Brazil. A total of 63 green turtles (10.4%), two olive ridleys (20.0%) and one hawksbill (3.0%) had shark-inflicted bites. Most bites could not be definitively attributed to scavenging or attacks on living turtles, but the presence of healed shark bites and freshly bleeding bites suggests that some attacks occurred pre-mortem. Bite characteristics suggest that tiger sharks Galeocerdo cuvier were responsible for most bites that could be identified to a particular species. Within green turtles, the only species with sufficient sample size, the probability of carcasses having been bitten increased with carapace length but did not vary across seasons and years. However, there was spatial variation in the probability of a carcass having been bitten by sharks. Our estimates of the minimum proportion of turtles attacked while alive (∼4%) and bitten overall are similar to other areas where shark-turtle interactions have been studied. Turtles likely are an important food for tiger sharks in northeastern Brazil, but further studies are needed to determine the relative frequencies of scavenging and predation.

Feeding ecology of Rivulus luelingi (Aplocheiloidei: Rivulidae) in a Coastal Atlantic Rainforest stream, southern Brazil

Feeding habits of the killifish Rivulus luelingi collected in a black water stream of the Coastal Atlantic Rainforest in southern Brazil were investigated. Eight samplings were made between April 2003 and January 2004. The diet, assessed through a similarity matrix with the estimated contribution values of food items, included microcrustaceans, aquatic immature insects (larvae and pupae), aquatic adult insects, terrestrial insects, insect fragments, spiders, and plant fragments. Differences in the diet according to temporal variations (months) were registered, but changes related with size classes evaluated and high/low precipitation period were not observed. The species presented an insectivorous feeding habit, and its diet in the studied stream was composed of autochthonous (mainly aquatic immature insects) and allochthonous (mainly insect fragments) material.

Temporal and ontogenetic variations in feeding habits of Hollandichthys multifasciatus (Teleostei: Characidae) in coastal Atlantic rainforest streams, southern Brazil

Feeding habits of the characin Hollandichthys multifasciatus were investigated. Samplings were made between March 2004 and February 2005 in two black water streams of the coastal Atlantic rainforest in southern Brazil. The diet, evaluated by qualitative and quantitative methods, included aquatic and terrestrial insects, decapods, oligochaetes, plants and spiders. Large individuals feed mainly on plants, terrestrial insects, and spiders, whereas small fish feed basically on plants and oligochaetes. The species showed an omnivorous feeding habit, and its diet was composed of autochthonous (mainly oligochaetes) and allochthonous (plants and terrestrial insects) material.

Hábitos alimentares de tubarões-martelo jovens, Sphyrna zygaena (Carcharhiniformes: Sphyrnidae), no litoral sul do Brasil

O presente estudo foi conduzido em duas comunidades da pesca artesanal nas cidades Guaratuba (Paraná) e Itapoá (Santa Catarina), no sul da costa brasileira. Os conteúdos estomacais de indivíduos Sphyrna zygaena foram identificados, sendo os itens alimentares agrupados em três categorias. As categorias mais importantes foram teleósteos (78,6%) e cefalópodes (60,7%), representados pela sardinha Harengula clupeola e a lula Loligo sp., ambos considerados como principais itens alimentares de S. zygaena na região estudada.