Aim To determine the origin and diversification of monachine seals using a phylogenetic framework. Methods Molecular sequence data from three mitochondrial genes (cyt b, ND1 and 12S), and one nuclear marker (an intron from the α‐lactalbumin gene) were examined from all extant species of monachine seals. Maximum likelihood and partitioned Bayesian inference were used to analyse separate and combined (mitochondrial + nuclear) data sets. Divergence times were estimated from the resultant phylogeny using nonparametric rate smoothing as implemented by the program r8s. Results Mirounga, Monachus and the Lobodontini form three well‐supported clades within a monophyletic Monachinae. Lobodontini + Mirounga form a clade sister to Monachus. Molecular divergence dates indicate that the first split within the Monachinae (Lobodontini + Mirounga clade and Monachus) occurred between 11.8 and 13.8 Ma and Mirounga, Monachus and the Lobodontini originated 2.7–3.4, 9.1–10.8 and 10.0–11.6 Ma, respectively. Main conclusions Two main clades exist within Monachinae, Monachus and Lobodontini + Mirounga. Monachus, a warm water clade, originated in the North Atlantic and maintained the temperate water affinities of their ancestors as they diversified in the subtropic regions of the Northern Hemisphere. The cold‐water clade, Lobodontini + Mirounga, dispersed southward to the cooler climates of the Southern Hemisphere. The Lobodontini continued south until reaching the Antarctic region where they diversified into the present‐day fauna. Mirounga shows an anti‐tropical distribution either reflective of a once cosmopolitan range that was separated by warming waters in the tropics or of transequatorial dispersal.
The Mediterranean monk seal Monachus monachus, is a critically-endangered species of which only two populations, separated by c. 4000 km, remain: the eastern Mediterranean (150-300 individuals) and the Atlantic/western Sahara populations (100-130 individuals). We measured current levels of nuclear genetic variation at 24 microsatellite loci in 12 seals from the eastern Mediterranean and 98 seals from the western Sahara population and assessed differences between them. In both populations, genetic variation was found to be low, with mean allelic richness for the loci polymorphic in the species of 2.09 and 1.96, respectively. For most loci, the observed allele frequency distributions in both populations were discontinuous and the size ranges similar. The eastern Mediterranean population had 14 private alleles and the western Sahara had 18, but with a much larger sample size. Highly significant differences in allele frequencies between the two populations were found for 14 out of 17 loci. F ST between the two populations was 0.578 and the estimated number of migrants per generation was 0.046, both clearly indicating substantial genetic differentiation. From a conservation perspective, these results suggest that each population may act as a source for introducing additional genetic variation into the other population.
Morbillivirus were isolated from Mediterranean striped dolphins (Stenella coeruleoalba) dying along the coasts of Italy and Greece in 1991. They were antigenically identical to the morbilliviruses isolated from striped dolphins in Spain in 1990.
The Mediterranean monk seal Monachus monachus is the most endangered seal in the world with < 600 ind. currently surviving. The species faces a number of threats to its survival: accidental entanglement has been identified as one of the most important amongst them. Here we made the first attempt to systematically describe the nature of this threat and assess its impact on Mediterranean monk seal populations. We based our study on information from an extensive literature review, questionnaires carried out in various locations in Greece and necropsies performed in Greece and in the Madeira Islands, Portugal. Our results indicate that accidental entanglement has been, and still is, a major threat to the species in its main distribution area in the northeastern Mediterranean, and that this threat may increase throughout the seal's range. Accidental entanglement occurs mainly with fishing nets, and affects mostly sub-adult seals. Short-term conservation actions should include the identification of critical pupping sites and their protection through the establishment and enforcement of protective measures. A long-term course of action will require detailed knowledge of the causes of accidental entanglement of Mediterranean monk seals in fishing gear.KEY WORDS: Endangered species · Mediterranean monk seal · Accidental entanglement · Conservation · Seal-fishery interactions · Greece · Madeira
Stomach contents were collected from 27 monk seal carcasses between 1997 and 2008 from different areas along the Greek coast. This sample included nine animals that had been deliberately killed and five accidental deaths due to fisheries interactions. Stomachs from monk seals of both sexes, including adults and subadults, were analysed. A total of 530 prey items from at least 71 prey species was identified, with approximately 74% of prey identified at least to genus, while 2.8% could be identified only to class level (i.e., fish or cephalopods). We found 266 cephalopods (50%), 253 fish (48%), a few non-cephalopod molluscs (1.5%), and two crustaceans (0.4%). Faecal samples were also collected but contained no identifiable prey remains. Octopuses were the most important prey in terms of numbers eaten and contribution to reconstructed prey biomass. The common octopus (Octopus vulgaris) (33.9% of prey by number) was around three times as numerous in the diet as the lesser octopus (Eledone cirrhosa) (11.1%). Fish of the families Sparidae (28.1%) and, to a lesser extent, Scorpaenidae (2.3%), Congridae (2.5%), and Atherinidae (2.5%) were also frequent in the stomachs. Many of the prey species recorded are of commercial fishery importance. Exploratory multivariate analysis (redundancy analysis [RDA]) indicated weakly significant seasonal, spatial, and interannual variation in diet and also suggested a relationship between diet composition and cause of death. No trends in diet related to sex or age class were identified. Sparids occurred more frequently in animals that had been deliberately killed than those that had died due to other causes, highlighting the interactions taking place between monk seals and fishing activities.
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