Genetic diversity and populational structure of the seahorse Hippocampus reidi (Syngnathidae) in north‐eastern Brazil: A conservationist approach

Abstract

1. Anthropic influence on the environment has caused extensive damage, with several species becoming vulnerable to extinction, such as Hippocampus reidi, the seahorse with the largest distribution area in Brazilian estuaries. For instance, in the Maracaípe River estuary, north-eastern Brazil, once a sanctuary for the species, this seahorse is now increasingly difficult to find.2. Recovery strategies for species threatened with extinction include the introduction of individuals from a demographically healthy population, or the captive breeding and subsequent release of individuals from the population at risk. This study evaluated the evolutionary potential and the best way to manage the recovery of the Maracaípe seahorse population.3. The genetic diversity of 30 adults and 99 juveniles of H. reidi collected in Maracaípe were compared with those of 29 adults from a nearby, demographically healthy population in Jericoacoara National Park, Ceará. Inter simple sequence repeat (ISSR) polymerase chain reaction (PCR) was used, amplifying 96 polymorphic fragments from the studied groups. 4. Adults and juveniles from Maracaípe had high diversity and low genetic differentiation. The neighbour-joining method, based on the number-of-differences model, revealed two clusters: one with adults and juveniles from Maracaípe; and the other with adults from Jericoacoara only. The most probable number of genetic groups (K = 2) was also obtained using Evanno's test, which was confirmed by STRUCTURE.The analysis of molecular variance showed that more than 30% of the differences occur between these two groups (Maracaípe and Jericoacora). The population differentiation observed between Maracaípe and Jericoacoarasuggests genetic incompatibility between the individuals in each area, and points to the risk of outbreeding depression. Therefore, a possible conservation strategy for the Maracaípe population is a native captive breeding programme and the release of offspring in this location, aiming at the demographic recovery of the population in the area.

Brazilian marine phylogeography: A literature synthesis and analysis of barriers

“…In Brazil, the split of the SEC at or around Cape São Roque was first recognized as a barrier to gene flow for the crustacean Panulirus argus (Diniz et al, 2005). Since then, several other molecular studies have endorsed the interaction between Cape São Roque and the split of the SEC as a barrier to gene flow, including the crustacean Micropogonias furnieri (Puchnick‐Legat & Levy, 2006), six fish species (Bezerra et al, 2018; Cortinhas et al, 2016; da Silva et al, 2016; Mendonça et al, 2011; Montes et al, 2018; Santos et al, 2006), mangrove species ( Rhizophora spp. : Francisco et al, 2018; Pil et al, 2011), a turtle ( Eretmochelys imbricata : Proietti et al, 2014) and three hermatypic corals ( Mussismilia hispida , Favia gravida , and Siderastrea radians : Nunes et al, 2011; Peluso et al, 2018).…”

Barriers to gene flow along the Brazilian coast: a synthesis and data analysis

“…The flow in opposite directions of the two Brazilian boundary currents was first proposed as a BGF in the phylogeographical study of the crustacean Micropogonias furnieri (Puchnick-Legat & Levy, 2006). Since then several other studies have tested and detected BGF at this region, including another crustacean (Panulirus argus: Diniz, Maclean, Ogawa, Cintra, & Bentzen, 2005), six fish species (Bezerra et al, 2018;Cortinhas et al, 2016;da Silva et al, 2016;Mendonca, Oliveira, Gadig, & Foresti, 2011;Montes et al, 2018;Santos et al, 2006), some plant species (Rhizophora spp. : Francisco, Mori, Alves, Tambarussi, & de Souza, 2018;Pil et al, 2011), and a turtle species (Eretmochelys imbricata: Proietti et al, 2014).…”