Robson Tamar da Costa Ramos

Effects of riparian vegetation on the structure of the marginal aquatic habitat and the associated fish assemblage in a tropical Brazilian reservoir

A zona riparia representa uma area de importantes interacoes, sejam biologicas, fisicas ou quimicas, entre o ecossistema terrestre e aquatico. Essas areas sao geralmente caracterizadas por uma alta diversidade de fauna, flora e processos ecologicos. Este estudo avalia a estrutura do habitat aquatico e a fauna de peixes com relacao a presenca e ausencia da mata ciliar natural em um reservatorio no Nordeste brasileiro. Amostragens foram realizadas em areas marginais onde a mata ciliar estava presente e onde esta havia sido removida para o plantio de cana-de-acucar. Em cada area, tres pontos de coleta foram amostrados durante o periodo chuvoso. Dados sobre a estrutura do habitat (elementos submersos e composicao do substrato), peixes e qualidade da agua foram coletados. Os dados foram analisados usando o indice de diversidade de Shannon-Wiener e a equitabilidade de Pielou. Escalonamento multidimensional nao metrico associado a um procedimento de permutacoes multiplas foi usado para avaliar as similaridades entre os pontos de coleta. A estrutura do habitat mostrou-se mais diversa em locais onde a mata ciliar nao havia sido removida. Lama foi o tipo de substrato mais abundante em areas onde a mata ciliar esteve intacta, enquanto que areia foi o tipo de substrato mais comum em areas onde a mata ciliar foi removida. Variaveis fisico-quimicas e nutrientes dissolvidos na agua apresentaram valores relativamente constantes em todos os locais estudados. Metynnis lippincottianus e Crenicichla menezesi estiveram associados com areas onde a mata ciliar foi removida, enquanto Cichlasoma orientale e Cichla ocellaris estiveram mais fortemente correlacionados com areas onde a mata ciliar estava preservada.

Application of Catchment- and Local-Scale Variables for Aquatic Habitat Characterization and Assessment in the Brazilian Semi-Arid Region

O estado do habitat fisico e influenciado por fatores que atuam em diversas escalas, como a geomorfologia, o clima, o regime hidrologico, o uso da terra e a qualidade da agua. Este trabalho quantifica a diversidade e a disponibilidade do habitat fisico em sistemas aquaticos naturais e artificials no semi-arido do Brasil, com o objetivo de levantar variaveis fisicas em escala local e de bacia de drenagem, e analisar sua importância na composicao de uma estrutura basica para a caracterizacao e avaliacao desses ambientes. Este estudo foi desenvolvido nas regioes de Serido/Borborema e Buique/Vale do Ipojuca. Estas areas sao consideradas de extrema importância biologica e sao identificadas como prioritarias para a conservacao da Caatinga. Os resultados mostram que o habitat aquatico no semi-arido brasileiro e diverso e dinâmico, compreendendo um conjunto amplo de elementos disponiveis para a colonizacao pelos organismos. Os rios mostraram uma gama de elementos do habitat marginal e da composicao do substrato igual ou superior aquela dos reservatorios. Alem disso, a composicao do habitat variou entre os dois tipos de ambiente estudados (rios/reservatorios) e com as estacoes do ano (seca/chuvosa). Os resultados apresentados tem implicacoes importantes para a conservacao dos ambientes aquaticos do semiarido. Tendo em vista que o habitat fisico e a estrutura basica para a colonizacao por parte dos organismos aquaticos, os mecanismos potenciais que mantem a biodiversidade aquatica ocorrem nos varios niveis da bacia de drenagem. Portanto, e fundamental identificar os componentes, ao longo dos sistemas riparios, que sao vitais na manutencao da sua integridade biologica. Palavras-chave: rios intermitentes, reservatorios, conservacao, composicao do substrato.

Effects of fishing technique on assessing species composition in aquatic systems in semi-arid Brazil

In most ecological field research, appropriate sampling is critical for the understanding of processes underlying fish populations and communities, and is even more important in heterogeneous environments such as the aquatic systems of the semi-arid region of Brazil. This study intends to make a contribution to the development of sampling programs and gear selection in aquatic systems of semi-arid Brazil by evaluating the effects of different fishing techniques on the assessment of richness and composition of the fish fauna in selected aquatic environments. Six sites were selected to represent typical artificial (reservoirs) and natural (intermittent streams) environments and four different types of sampling gear were applied to each site during four occasions. The present study shows that when selecting sampling techniques to be used in aquatic systems in semi-arid Brazil, one must consider the objectives of the study, e.g. ecological or taxonomic, in order to decide on inclusion of rare species in the sampling population. Also, the effect of the sampling gear on natural abundances of fish must be considered given that some sampling techniques are highly detrimental to fish population numbers.

Ichthyofauna of the Parnaíba river Basin, Northeastern Brazil

The Parnaiba River is the largest hydrographic basin with its limits entirely within the northeastern region of Brazil. It is one of the few perennial rivers in the Brazilian Northeastern Region, running predominantly in the area of Caatinga on the eastern portion (with intermittent drainages associated to this type of environment), and partly extending into the Cerrado region on the western portion. The objective of this study was to describe the diversity of freshwater fishes of the Parnaiba River basin by conducting a comprehensive ichthyofauna inventory of the basin. The sampling design of this study was based on the placement of (1) Fixed Sites for seasonal collection (dry and wet season, two years) in the three portions of the main course of the Parnaiba River, and (2) “Aquarap” protocol collections which covered the entire basin. The collection effort consisted of 244 sampling sites surveyed along the entire basin between the years 2004 and 2011. Fish were collected with the use of seines, cast nets, gill nets and dip nets; only the first two fishing gears were used in Fixed Sites. As a result, 146 species of freshwater fish were recorded in the Parnaiba River basin, distributed in 103 genera, 36 families and 11 orders. The registered endemism reached a total of 54 species.

Ichthyofauna of Seridó/Borborema: a semi-arid region of Brazil

The Serido/Borborema region is located between the States Paraiba and Rio Grande do Norte and a priority area for conservation of the Caatinga. This region is under the hydrological influence of the middle portion of Piranhas-Acu River basin. Previous systematic inventories of the ichthyofauna of this Caatinga’s area are not significant. The Caatinga fish fauna is threatened due the advancement of historic anthropogenic activities, mainly agricultural. Furthermore, another relevant aspect is the recent governmental decision of transferring water from Sao Francisco River to other Northern river basins, which includes the Piranhas-Acu basin. This study performed a systematic survey of the Serido/Borborema’s ichthyofauna. The sites were sampled during the years 2006 and 2007 (four annual, diurnal samples), using three different types of gear: beach seine nets, cast net and gillnets. We captured 13,009 individuals of 5 orders, 14 families, 28 genera and 35 species of fish. The predominant orders were Characiformes (21 species), Siluriformes (6) and Perciformes (5). The greatest number of species (11) was catch from the family Characidae, followed by Cichlidae (5) and Loricariidae (4). This inventory produced a comprehensive sampling of the middle portion of Piranhas-Acu River basin and its result overcomes the diversity reported in previous studies (22 species) on the same region.

Cynolebias parnaibensis, a new seasonal killifish from the Caatinga, Parnaíba River basin, northeastern Brazil, with notes on sound producing courtship behavior (Cyprinodontiformes: Rivulidae)

Cynolebias parnaibensis from the Caninde River drainage, Parnaiba River basin, northeastern Brazil, is described. It is considered to be a member of a clade endemic to the Caatinga. The clade is diagnosed, e. g., by a series of structural modifications of the pharyngeal jaw apparatus, which is related to the sound production exhibited by males during courtship behavior. The courtship sound of C. parnaibensis consists of a single pulse named as thump (duration 0.031-0.133s; interthump intervals 0.020-8.319s; dominant frequency 70.3-93.8 Hz). The new species is distinguished from all other congeners by a combination of 27-31 neuromasts around eye, 29-33 supraorbital neuromasts, 16-18 dorsal-fin rays and 19 anal-fin rays in males, 28-31 caudal-fin rays, 33-36 scales in the longitudinal series, 3+10 gill-rakers in the first branchial arch, absence of second pharyngobranchial teeth, absence of contact organs on the flank scales, 34-35 vertebrae, absence of teeth on vomer, and presence of transverse series of scales on the anal-fin base.

Food resources used by three species of fish in the semi-arid region of Brazil

in aquatic systems in semi-arid Brazil, providing evidence of the importance of these habitats as supporters of large consumers like fish. The diet of thethree species studied was diverse, feeding on a range of food items, from microalgae to fish. Despite that, a few items were mo reimportant to each of the study species. These results and the relatively high rates of stomach fullness indicate that a diverseand abundant food range is available in the study sites, but species seem to select some food resources. The present studyprovides evidence that despite being highly variable, intermittent and semi-permanent aquatic systems in semi-arid Brazil areable to trophically sustain large consumers.Os ambientes aquaticos temporarios e semi-permanentes do semiarido brasileiro tem sido mostrados como importantes sitiosque possuem uma diversa fauna de peixes. Desta forma, esses ambientes devem ser capazes de sustentar, do ponto de vistatrofico, populacoes de peixes que se alimentam em diversos niveis troficos. O presente estudo tem como objetivo descrever ohabito alimentar de

A new species of armored catfish Parotocinclus (Siluriformes: Loricariidae) from the rio Parnaíba basin, northeastern, Brazil

Estudos taxonomicos recentes indicaram a presenca de varias especies nao descritas na bacia do rio Parnaiba. Dentre estas, uma nova especie de Parotocinclus endemica desta drenagem e aqui descrita. Ela difere da maioria dos seus congeneres, incluindo as simpatricas P. haroldoi e P. cearensis, por apresentar nadadeira adiposa vestigial ou rudimentar (vs. nadadeira adiposa desenvolvida). Este carater tambem esta presente em P. bidentatus e P. muriaensis (ambos do rio Paraiba do Sul, sudeste do Brasil), P. spilurus (bacia do rio Jaguaribe, nordeste do Brasil), P. seridoensis (bacia do rio Piranhas-Acu, nordeste do Brasil), P. halbothi (bacias dos rios Trombetas e Marowijne, norte do Brasil e no Suriname) e P. dani (do rio Tapajos no Estado do Mato Grosso, Brasil). A nova especie difere destas principalmente pelo abdomen extensivamente coberto por placas dermicas largas. Tambem difere de P. haroldoi e P. cearensis pela presenca de faixas claras entre a ponta do focinho e as narinas.

Phenacorhamdia cabocla , a new heptapterid from the Parnaíba River basin, Northeastern Brazil (Siluriformes: Heptapteridae)

Phenacorhamdia Dahl, 1961 comprises 11 valid species of small demersal and solitary catfishes which occur mainly along riverbeds and are widely distributed throughout rivers of South America. The genus is included within the Nemuroglanis subclade, and species of Phenacorhamdia can be separated from other heptapterid catfishes through external and internal characters. Diagnostic characters include a prognathous mouth, first ray of dorsal and pectoral fins flexible, eight or nine branched rays in the lower lobe of caudal fin, and optic foramen reduced. A new species of Phenacorhamdia is described herein from the upper Parnaíba river basin. Phenacorhamdia cabocla sp. nov is distinct from its congeners by: total vertebrae 44, nine of which with pleural ribs; bifid neural spines until vertebrae 13; last precaudal vertebrae lacking pleural ribs; 7-8 branchiostegal rays; pectoral-fin rays i+6; first pterygiophore of dorsal-fin associated to the neural spine of twelfth vertebrae; dorsal-fin pterygiophores associated to vertebrae 12 to 16; anal-fin with nine branched and 3-4 unbranched rays; upper and lower lobes of caudal fin with 8-9 branched rays each; adipose fin corresponding to 14.9%-18.1% of standard length; and snout length corresponding to 30.0%-35.9% of head length.