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

Abstract

1. 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.2. 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 (Ф ST = 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.3. 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.

Phylogeography of the reef‐building polychaetes of the genus Phragmatopoma in the western Atlantic Region

“…While genetic differentiation between Florida and the eastern Caribbean has previously been documented in P. caudata (Drake et al, 2007), our work reveals continued genetic connectivity across the Amazon-Orinoco Barrier, among populations separated by as much as 9000 km. The Amazon plume is an important barrier to dispersal for a variety of marine species, such as corals (Nunes et al, 2009(Nunes et al, , 2011, crustaceans (Terossi & Mantelatto, 2012), echinoderms (Lessios et al, 2003) and reef fish (Mendonc ßa et al, 2013). However, it is considered a 'soft barrier' or 'filter' because of the large number of shared fish species on either side of the barrier (Floeter et al, 2008).…”

A new map of the tiger shark (Galeocerdo cuvier) genetic population structure in the western Atlantic Ocean: Hypothesis of an equatorial convergence centre

“…Determining the level of connectivity between ecological units of a population is fundamental to understanding ecosystem dynamics. Characterization of discrete evolutionary units is often compounded for species of marine fauna that exhibit wide distribution ranges, such as sharks (Mendonça, Oliveira, Gadig, & Foresti, ). Widespread shark species often inhabit environments with differing ecological characteristics, such as coastal or oceanic regions in tropical or subtropical waters.…”

“…Differences in population genetics may also develop within a continuously distributed species when there is limited gene flow as a result of the distance between populations (Ashe et al, ). Long distances may restrict reproduction to only proximate individuals (Mendonça et al, ; Mendonça, Oliveira, Gadig, & Foresti, ). In such cases, it is expected that geographical and genetic distances among populations will be positively correlated, a pattern recognized as isolation by distance (Wright, ).…”

Biology of Rhizoprionodon lalandii (Elasmobranchii: Carcharhinidae) captured by the artisanal fishery of Margarita Island, Venezuela

“…Sin embargo, nueva información relevante ha sido generada en Brasil (Mota et al, 2005;Andrade et al, 2008;Lessa et al, 2009;Macedo et al, 2012;Mendonça et al, 2009;Bornatowsky et al, 2012;Mendonça et al, 2013), Colombia (Martinez et al, 2012) y Venezuela, por lo que se sugiere reevaluar el estato de conservación actual de la especie.…”

“…Existen diversos estudios sobre la especie en Brasil que incluyen aspectos sobre su biología reproductiva (Ferreira, 1988;Lessa, 1988;Menni & Lessa, 1998;Motta, Namora, Gadig, & Braga, 2007;Andrade, Silva-Junior, & Vianna, 2008;Macedo, Sousa, & Batista, 2012;Martínez, Álvarez, & Acero, 2012), genética (Mendonça, Oliveira, Gadig, & Foresti, 2009;2013), proporción sexual, frecuencia de longitudes, relación longitud-peso (Motta, Gadig, Namora, & Braga, 2005), edad y crecimiento (Lessa, Santana, & Almeida, 2009) y aspectos alimentarios (Lima, Daros, Mazzoleni, & Hostim-Silva, 2000;Bornatowsky, Heithaus, Albilhoa, & Corrêa, 2012). En contraste, en Venezuela a pesar de que hace más de 50 años que se reconocen sus capturas en las pesquerías (Méndez-Arocha 1963;Ginés et al1972), la información disponible sólo abarca una descripción general de la especie realizada por Cervigón & Alcalá (1999) y la relación longitud-peso para ejemplares capturados en Isla Margarita (Tagliafico, Rago, & Rangel, 2014).…”