Raul Rennó Braga

Feeding ecology of fishes: an overview of worldwide publications

The impact of human activity is evident in the depletion of fish populations worldwide. This being the case, there is an urgent need to discover the true biodiversity of the world before the loss rate exceeds its limits. Because the feeding ecology of a species is thoroughly linked to its population dynamics, knowledge of the feeding ecology contributes to the understanding of such subjects as resource partitioning, habitat preferences, prey selection, predation, evolution, competition and energy transfer within and between ecosystems. Such ecological information is of great value when developing conservation strategies and is, therefore, a key element in the protection of species and ecosystems. Our paper reviews the geographic and/or biogeographic regions where the majority of studies concerning the feeding ecology of fish have been conducted, with the goal of identifying regions and/or environments in need of further attention. In addition, we identify which journals published more papers regarding the subject. Our analysis was conducted by assessing studies indexed on the ISI Web of Science database. We detected a lack of data concerning several aspects of the feeding of fish, such as: threatened species; freshwater habitats especially within the Neotropical, Ethiopian and Oriental realms; species rich developing countries; and, when considering marine fish, the Eastern Indo-Pacific region. Considering the calculated weight for each journal, Ecology of Freshwater Fish, Neotropical Ichthyology and Environmental Biology of Fishes were the most important ones. If we ignore these gaps in our knowledge we run the risk of losing a huge amount of information without knowing it ever existed, especially in the fast changing world we face today.

Non-native species and invasion biology in a megadiverse country: scientometric analysis and ecological interactions in Brazil

The number of invasions by non-native species and their negative impacts is increasing, especially in developing megadiverse countries. The current catalogue of hypotheses, concepts and management policies related to invasions was typically created and evaluated in temperate and economically rich regions. So what we know about invasion biology may not provide a general pattern applicable to developing megadiverse regions. All recent reviews have indicated a demand for more studies in tropical and megadiverse regions. Additionally, potential differences in the quality and availability of data may preclude any comparative analyses between developing and developed nations and hinder global strategies to combat invasions. Therefore, it is important to synthesize the existing knowledge on the subject in order to aid conservation activities in such regions. We conducted a systematic review of non-native species and invasions in Brazil and found geographical bias towards the most populated regions and biomes. Plants and fish were the most studied groups and were, for the most part, intentionally introduced, usually to meet some economic interest. We also noted the dominance of studies concerning terrestrial and freshwater ecosystems. Most studies did not address species interactions and, in the few cases where they did, the most frequently studied were between non-native and native species. There was a paucity of research beyond the level of species records and descriptive patterns. We highlight major vectors of introduction, the number of non-native species (proxy to colonization pressure) and papers (proxy to propagule pressure) related to each vector and the need for designed surveys and experiments focusing on specific invasion hypotheses and/or species interactions. We indicate major gaps and biases nationally that should be the focus for future studies, and that can serve as examples for other megadiverse countries.

Shark mislabeling threatens biodiversity.

As commercial fisheries struggle to apply regulatory and legal mechanisms that depend on reliable species-specific data ([ 1 ][1]), the shark industry faces an even greater obstacle to transparency: Sellers change product names to overcome consumer resistance. For instance, South Africa sells shark

Fishes of the Atlantic Rain Forest Streams: Ecological Patterns and Conservation

Fishes constitute more than one half of the species of vertebrates, with around 32,000 living species (Froese & Pauly, 2011). Approximately 40% of this global fish diversity lives in freshwater environments, which represents less than 1% of the surface of the Earth (Dudgeon et al., 2006). In the Neotropical Region, freshwater fishes constitute a taxonomically distinct fauna that extends throughout the continental waters from Central Mexico to the southernmost tip of South America. This zoogeographical region is known to harbor the richest and most diverse freshwater fish fauna of the whole planet (Gery, 1969; Vari & Malabarba, 1998; Lundberg et al., 2000; Albert et al., 2011). The Atlantic Rain Forest is one of the richest biomes in the Neotropics mainly due to the variety of habitats throughout the range of the forest types and subtypes, which originally covered a wide stripe of the Brazilian coastline (Morellato & Haddad, 2000). Considering the fact that the definition of the limits and forest types of the Brazilian Atlantic Rain Forest is controversial and beyond the scope of this study, this vegetation domain was considered here in a narrower sense, comprising the coastal forest formations between 6–300 S, with elevations from sea level to approximately 1,000 meters. In this sense, this forest is dispersed along degraded landscapes, embracing some of the largest and oldest Brazilian urban areas, where more than 150 million people live. The Atlantic Rain Forest constitutes one of Brazil s most important vegetation domains, because of its historical relationship with the colonization of the country, and also in view of the role that it plays in the conservationist scenario (Silva, 2003). In the broadest and most generic sense of the forest formations, this biome is one of the most biodiverse and endangered ecosystems in the world (Myers et al., 2000). The region bounded by this forest has a high percentage of fish species with restricted distribution, as a result of the great number of independent coastal drainages (or groups of basins), and the isolating effect of mountain ranges and seawater among coastal rivers (Bizerril, 1994; Menezes et al., 2007). In fact, according to our survey a great amount (70%) of the freshwater fishes can be considered exclusive to the coastal drainages of this vegetation domain The high rate of speciation and high degree of geographic endemism is an important factor that needs to be considered in the conservation policies of the Atlantic Rain Forest remains, as this biome is located in the most populated regions of the country,

Elasmobranchs Consumption in Brazil: Impacts and Consequences

Commercial fisheries struggle to apply regulatory and legal mechanisms that depend on reliable species-specific data, and the shark industry faces an even greater obstacle to transparency with sellers changing product names to overcome consumer resistance. Fraudulent representation or mislabeling of fish, including sharks and rays, has been recorded in some countries. In Brazil, for instance, sharks are sold as “cacao” – a popular name attributed for any shark or ray species; however, according to consumer’s knowledge of a large city of southern Brazil, more than 70% of them are often unaware that “cacao” refers to sharks. Today, the Brazilian market has a high interest in encouraging people to eat “cacao” meat, mainly because of their attractive prices. This raise a number of questions, mainly in respect to the knowledge of people/consumers, as what are they eating, and why the Brazilian meat market has grown so much in the last years.

Population structure and reproduction of Mimagoniates microlepis with a new hypothesis of ontogenetic migration: implications for stream fish conservation in the Neotropics

Longitudinal size segregation and reproductive aspects of Mimagoniates microlepis were studied along the catchment of the Piraquara River, a tributary of the Iguaçu River. Monthly fish sampling were completed at four sites along a longitudinal gradient. In addition, we summarized and compared key species-ecological traits of three different populations of this species. Data from the two additional populations were obtained from the literature. Our findings concerning population structure and reproduction of this species demonstrate that ontogenetic migration occurs within this population. During flash floods small individuals (C1) are carried to downstream habitats (P1). As they grow, we assume that their swimming capacity tends to increase and they are able to explore upstream habitats. This ontogenetic migration dynamic is a common and underexplored pattern for small stream fish in the Neotropics, and it helps to ensure, as a consequence, the long term persistence of the population along the entire hydrographic basin. Therefore, the alteration of only one portion of the river can compromise the entire migration process and consequently the entire population. In addition, the present study is the only source of ecological information for this population from before the recent construction of the Piraquara II dam. This reinforces the urgent need for conservation strategies for this population of M. microlepis and other similar populations or species.

Gastric lavage for dietary studies of small fishes: Efficiency, survival and applicability

Studies on feeding ecology provide information of great importance to the understanding of aquatic ecosystems. However, these studies usually require the sacrifice of animals. In view of this problem, the presently reported study aims to evaluate the effectiveness and applicability of the gastric lavage method for small catfishes. There was no mortality recorded for the 80 specimens of Rhamdia quelen (Quoy et Gaimard, 1824) and after recovery from anaesthesia all fish presented a normal swimming pattern. With the gastric lavage method we were able to retrieve 71.4% of the stomach contents of 34 specimens of Pimelodella pappenheimi Ahl, 1925. These results serve as a stimulus for studies prioritizing non-lethal techniques. These methods would ensure greater knowledge about ecology and conservation of smaller fishes, especially to populations of small and rare species that are the most endangered in freshwater systems.