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Bottlenose dolphins (Tursiops truncatus) occupy a wide range of coastal and pelagic habitats throughout tropical and temperate waters worldwide. In some regions, "inshore" and "offshore" forms or ecotypes differ genetically and morphologically, despite no obvious boundaries to interchange. Around New Zealand, bottlenose dolphins inhabit 3 coastal regions: Northland, Marlborough Sounds, and Fiordland. Previous demographic studies showed no interchange of individuals among these populations. Here, we describe the genetic structure and diversity of these populations using skin samples collected with a remote biopsy dart. Analysis of the molecular variance from mitochondrial DNA (mtDNA) control region sequences (n = 193) showed considerable differentiation among populations (F(ST) = 0.17, Phi(ST) = 0.21, P < 0.001) suggesting little or no female gene flow or interchange. All 3 populations showed higher mtDNA diversity than expected given their small population sizes and isolation. To explain the source of this variation, 22 control region haplotypes from New Zealand were compared with 108 haplotypes worldwide representing 586 individuals from 19 populations and including both inshore and offshore ecotypes as described in the Western North Atlantic. All haplotypes found in the Pacific, regardless of population habitat use (i.e., coastal or pelagic), are more divergent from populations described as inshore ecotype in the Western North Atlantic than from populations described as offshore ecotype. Analysis of gene flow indicated long-distance dispersal among coastal and pelagic populations worldwide (except for those haplotypes described as inshore ecotype in the Western North Atlantic), suggesting that these populations are interconnected on an evolutionary timescale. This finding suggests that habitat specialization has occurred independently in different ocean basins, perhaps with Tursiops aduncus filling the ecological niche of the inshore ecotype in some coastal regions of the Indian and Western Pacific Oceans.

Pilot whales (Globicephala spp.) provide an interesting example of recently diverged oceanic species with a complex evolutionary history. The two species have wide but largely non-overlapping ranges. Globicephala melas (longfinned pilot whale; LFPW) has an antitropical distribution and is found in the cold-temperate waters of the North Atlantic and Southern Hemisphere, whereas Globicephala macrorhynchus (short-finned pilot whale; SFPW) has a circumglobal distribution and is found mainly in the tropics and subtropics. To investigate pilot whale evolution and biogeography, we analysed worldwide population structure using mitochondrial DNA (mtDNA) control region sequences (up to 620 bp) from a variety of sources (LFPW = 643; SFPW = 150), including strandings in New Zealand and Tasmania, and whale-meat products purchased on the markets of Japan and Korea. Phylogenetic reconstructions failed to support a reciprocal monophyly of the two species, despite six diagnostic substitutions, possibly because of incomplete lineage sorting or inadequate phylogenetic information. Both species had low haplotype and nucleotide diversity compared to other abundant widespread cetaceans (LFPW, p = 0.35%; SFPW, p = 0.87%) but showed strong mtDNA differentiation between oceanic basins. Strong levels of structuring were also found at the regional level. In LFPW, phylogeographic patterns were suggestive either of a recent demographic expansion or selective sweep acting on the mtDNA. For SFPW, the waters around Japan appear to represent a centre of diversity, with two genetically-distinct forms, as well as a third population of unknown origin. The presence of multiple unique haplotypes among SFPW from South Japan, together with previously documented morphological and ecological differences, suggests that the southern form represents a distinct subspecies and/or evolutionary significant unit.

Estimating the abundance of long-lived, migratory animals is challenging but essential for managing populations. We provide the first abundance estimates of endangered humpback whales Megaptera novaeangliae from their breeding grounds in Oceania, South Pacific. Using fluke photo-identification (1999−2004, n = 660 individuals) and microsatellite genotypes (1999−2005, n = 840 individuals), we estimated abundance with open capture-recapture statistical models. Total Oceania abundance and trends were estimated from 4 primary and 5 secondary sampling sites across the region. Sex-specific genotype data enabled us to account for the difference in capturability of males and females, by doubling male-specific estimates of abundance derived from genotypes. Abundance estimates were congruent between primary-and secondaryregion data sets, suggesting that the primary regions are representative of all Oceania. The best estimate of total abundance was 4329 whales (3345−5313) in 2005, from a sex-specific POPAN super-population model, which includes resident whales and those migrating through the surveyed areas. A doubled-male POPAN abundance estimate from 2003 (n = 2941, 95% CI = 1648−4234) was considered the most plausible for the 4 primary survey areas and was similar to the 2003 doubled-male estimate derived from Pradel capture probabilities (n = 2952, 95% CI = 2043−4325). Our results confirm that Oceania is the least abundant humpback whale breeding population in the southern hemisphere. Pradel models showed no significant trend in abundance, which contradicts the recovery seen in most other populations throughout the world. Thus we suggest that the whales in this area warrant continued study and management attention.KEY WORDS: Megaptera novaeangliae · South Pacific · Capture-recapture · Genotyping · Endangered speciesResale or republication not permitted without written consent of the publisher

Gray's spinner dolphins Stenella longirostris longirostris are found in apparently relatively small and discrete communities around many islands throughout the Pacific. However, the boundaries of these communities, on the scale of a dolphin's lifespan or across generations, are unknown. Here we report a combined demographic and genetic approach to describing the isolation and interchange of insular spinner dolphins among island communities of the Society Archipelago, French Polynesia. Dorsal fin photographs for individual identification and biospy samples for genetic analyses (n = 154) were collected from 6 island communities during 189 small-boat surveys over 3 yr. Capture-recapture analyses at Moorea (our primary study site), based on long-term observations of distinctively marked individuals and microsatellite genotypes (12 loci), indicated a local community of about 150 dolphins. This community appeared relatively closed on an intra-generational scale, as confirmed by resightings of individuals across 15 yr. Surveys around neighbouring islands indicated the presence of similar distinct communities, likely to follow demographic patterns similar to Moorea, with relatively low levels of interchange between communities. Overall, significant differentiation at both mitochondrial and nuclear levels indicated restricted gene flow among neighbouring communities, although some individual movement was documented. High levels of insular mitochondrial DNA (mDNA) genetic diversity (female long-term effective population size [N ef ] ~ 100 000) contrasted with demographic characteristics. No evidence of bottlenecks was found in microsatellite allele frequencies or mtDNA haplotypes, discounting the possibility of a recent founder effect. Instead, we suggest that this genetic pattern is the result of metapopulation structure, based on numerous insular communities evolutionarily connected through male and female gene flow.

Understanding the role and operation of top predators, such as seabirds, in marine systems requires investigation of their diet and feeding ecology. Knowledge of foraging patterns is essential when responding to many practical and theoretical questions related to marine ecology, behavioural ecology, ecophysiology and the management and conservation of marine ecosystems (Ashmole, 1971;Croxall, 1987;Hunt and Schneider, 1987;Monaghan, 1996;Ricklefs, 1983). However, excluding direct observation (by definition limited in time and space), recording the activity at sea of animals foraging offshore, from a few to thousands of kilometres away from their breeding colony, is challenging. During recent years, the study of seabirds' foraging behaviours has been facilitated by the development of new technologies resulting from electronic miniaturisation. Determining the location of individuals at sea is now possible using satellite tags (Jouventin and Weimerskirch, 1990;Weimerskirch et al., 2002) or light sensors (Wilson et al., 1995a). It is also of primary importance, however, to distinguish the bird's different activities at sea (flying, diving and resting), but to date quantification of their time budget has remained somewhat problematic, especially for medium and small-sized species such as larids and alcids.The activities of seabirds have been investigated through the use of specialist electronic loggers that record a few activities only, depending on the type of sensor that they carry, i.e. pressure, conductivity, acceleration and temperature sensors, and propellers (Mohus, 1987;Wilson et al., 1992Wilson et al., , 1995bAfanasyev and Prince, 1993;Wilson, 1995;Yoda et al., 1999;Ropert-Coudert et al., 2002). However, the specialisation of those devices has not permitted simultaneous recording of both time budget and diving behaviour in flying-diving seabirds. To overcome this problem, new devices storing data from wingbeat (microphone membrane 206, 1929-1940 © 2003 We tested the use of commercially available electronic time-depth recorders (TDRs) to quantify activities and thus total time budgets of seabirds. This new method involved first fitting TDRs onto the birds' bellies (not on their backs), and, secondly, analysing continuous recordings of temperature, light and pressure to differentiate activities on land and at sea. The birds studied were 12 common guillemots Uria aalge rearing chicks at Hornøya, in northern Norway. The method successfully recorded five different activities: at the colony, flying, diving, and resting or active at the sea surface. Overall, common guillemots spent 68% of their time at the colony and 32% at sea. While at sea, the birds spent the majority (77%) of their time at the surface, during which they were active 64% of the time, and rested only 13%. Birds engaged in the costly behaviours of flying and diving for shorter times (11% and 12% of their time at sea, respectively). The method allowed us to differentiate between two types of trips to sea based on the presence (foraging trips: 77% ...

The susceptibility of the Y chromosome to sexual selection may make this chromosome an important player in the formation of reproductive isolating barriers, and ultimately speciation. Here, we investigate the role of the Y chromosome in phenotypic divergence and reproductive isolation of spinner dolphin (Stenella longirostris) ecotypes. This species contains six known ecotypes (grouped into four subspecies) that exhibit striking differences in morphology, habitat and mating system, despite having adjacent or overlapping ranges and little genetic divergence at previously studied mtDNA and autosomal markers. We examined the phylogeographic structure for all six ecotypes across the species range (n = 261, 17 geographic locations) using DNA sequences from three Y chromosome markers, two maternally inherited mitochondrial (mtDNA) markers, and a biparentally inherited autosomal intron. mtDNA and autosomal analyses revealed low divergence (most Φ(ST) values <0.1) between ecotypes and geographic regions, concordant with previous studies. In contrast, Y intron analyses revealed fixed differences amongst the three most phenotypically divergent groups: S. l. longirostris vs. S. l. roseiventris vs. combined S. l. orientalis/S. l. centroamericana/Tres Marias ecotypes). Another ecotype (whitebelly), previously postulated to be a hybrid between the two phenotypically most divergent ecotypes, had Y haplotypes from both putative parent ecotypes, supporting a hybrid designation. Reduced introgression of the Y chromosome has previously been observed in other organisms ranging from insects to terrestrial mammals, and here we demonstrate this phenomenon in a marine mammal with high dispersal capabilities. These results indicate that reduced introgression of the Y chromosome occurs in a wide taxonomic range of organisms and support the growing body of evidence that rapid evolution of the Y chromosome is important in evolutionary diversification.

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