Evidences of possible influences of methylmercury concentrations on condition factor and maturation of Lophius vomerinus (Cape monkfish).

Muscle and liver tissues of Lophius vomerinus off the coast of Namibia were analysed to investigated the influence of MeHg on the biological parameters of L.vomerinus by (i) determining if the variability in total MeHg concentrations is influenced by length, maturity status and sex, and (ii) assessing if there is a relationship between biological indices (Condition factor (K), Gonadosomatic Index (GSI) Hepatosomatic Index (HSI)) and MeHg concentrations. Correlations between total MeHg concentrations and fish length, K and HSI were observed. A weak positive correlation was observed between total MeHg and GSI for combined sex. Total MeHg concentration in tissues of L. vomerinus is significantly dependent on the maturity stages (p < 0.05). K was significantly inversely correlated with total MeHg in tissues of L. vomerinus. The evidence presented in this study suggests that MeHg in L. vomerinus tissues could be detrimental to both its physiology and population dynamics.

Mitocondrial COI and 16S rDNA sequences support morphological identification and biogeography of deep-sea red crabs of the genus Chaceon (Crustacea, Decapoda, Geryonidae) in the Eastern Central and South Atlantic Ocean.

The geographical spreading of new fishing activities and the increasingly deeper locations of these activities have shown the worldwide distribution of gerionid crabs and new descriptions of Chaceon taxa. However, incomplete penetrance, variable expressivity, and phenotypic overlap make the morphometric identification of these species difficult. In this study, partial sequences of the cytochrome c oxidase subunit 1 (COI) and 16S mitochondrial ribosomal RNA (16S rRNA) genes have been analyzed in Chaceon species from the Eastern Central and South Atlantic and compared with sequences of species from Western Atlantic. Our results corroborate the proposed morphological species and highlight the significant separation of the Eastern Atlantic species and those from Atlantic coasts of South America for both markers (97% Bayesian posterior probability, BPP / 83% Bootstrap replicates, BT). Interestingly, Chaceon sanctaehelenae shows a closer relationship with the species of the American coast than with those from the Eastern Atlantic. On the other hand, while COI marker clearly separates Chaceon atopus and Chaceon erytheiae species (99 BPP / 91% BT), these species share haplotypes for the 16S rRNA marker, pointing to a recent speciation process. Moreover, a close relationship was observed between Chaceon maritae and Chaceon affinis (94% BPP / 77% BT). The topologies of the trees obtained indicate that the ancestor of this genus was closer related to those species from South America than to those from the Eastern Atlantic.