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Taxonomy is an imprecise science that delimits the evolutionary continuum into discrete categories. For marine mammals, this science is complicated by the relative lack of morphological data for taxa that inhabit remote and often vast ranges. We provide guidelines to promote consistency in studies relying primarily on molecular genetic data to delimit cetacean subspecies from both populations and species. These guidelines identify informational needs: basis for the taxonomic hypothesis being tested, description of current taxonomy, description of relevant life history, sample distribution, sample size, number and sequence length of genetic markers, description of measures taken to ensure data quality, summary statistics for the genetic markers, and analytical methods used to evaluate the genetic data. We propose an initial set of quantitative and qualitative standards based on the types of data and analytical methods most readily available at present. These standards are not expected to be rigidly applied. Rather, they are meant to encourage taxonomic arguments that are consistent and transparent. We hope professional societies, such as the Society for Marine Mammalogy, will adopt quantitative standards that evolve as new data types and analytical methods become widely available.

Identifying demographic changes is important for understanding population dynamics. However, this requires long-term studies of definable populations of distinct individuals, which can be particularly challenging when studying mobile cetaceans in the marine environment. We collected photo-identification data from 19 years (1992-2010) to assess the dynamics of a population of bottlenose dolphins (Tursiops truncatus) restricted to the shallow (7 m) waters of Little Bahama Bank, northern Bahamas. This population was known to range beyond our study area, so we adopted a Bayesian mixture modeling approach to mark-recapture to identify clusters of individuals that used the area to different extents, and we specifically estimated trends in survival, recruitment, and abundance of a "resident" population with high probabilities of identification. There was a high probability (p= 0.97) of a long-term decrease in the size of this resident population from a maximum of 47 dolphins (95% highest posterior density intervals, HPDI = 29-61) in 1996 to a minimum of just 24 dolphins (95% HPDI = 14-37) in 2009, a decline of 49% (95% HPDI = approximately 5% to approximately 75%). This was driven by low per capita recruitment (average approximately 0.02) that could not compensate for relatively low apparent survival rates (average approximately 0.94). Notably, there was a significant increase in apparent mortality (approximately 5 apparent mortalities vs. approximately 2 on average) in 1999 when two intense hurricanes passed over the study area, with a high probability (p = 0.83) of a drop below the average survival probability (approximately 0.91 in 1999; approximately 0.94, on average). As such, our mark-recapture approach enabled us to make useful inference about local dynamics within an open population of bottlenose dolphins; this should be applicable to other studies challenged by sampling highly mobile individuals with heterogeneous space use.

Data on morphometrics are central to understanding key features of both population and behavioral ecology, including phenotypic differences between species (Perryman and Lynn 1993, Meijaard and Groves 2004) and populations (Perryman and Lynn 1994), life history traits such as patterns of individual growth (Read et al. 1993, Lee and Moss 1995), and morphological differences related to mating systems (Boonstra et al. 1993, Tolley et al. 1995, Plavcan and van Schaik 1998). In the marine environment, it has proved difficult to obtain measurements from free-ranging cetaceans. Capture operations can yield precise data on morphometrics (e.g., Read et al. 1993), but such disruptive procedures are generally not feasible and are restricted to smaller species. On a more remote level, photogrammetric approaches have been successfully applied to estimate body size from aerial platforms (e.g., Perryman and Lynn 1993) and from underwater images (Klimley and Brown 1983, Spitz et al. 2000), but stereophotogrammetric methods require a camera configuration that is somewhat cumbersome (Klimley and Brown 1983, Brager et al. 1999, Brager and Chong 1999), and can be difficult to implement from small-boat research platforms alongside routine data collection. We describe a simple approach for obtaining morphometric measurements based on photographing two laser dots that have been projected onto the body of a whale using two small laser-pointers. These laser-pointers are mounted in a parallel orientation to maintain a fixed and known separation distance, and the dots therefore provide a scale of known dimension on the image of the whale that can be used to calibrate morphometric measurements. The lightweight laser setup can be conveniently mounted on a camera lens, allowing this approach to be implemented by a single photographer in conjunction with photo-identification studies. We demonstrate the

Population substructure has important implications for a species’ ecology and evolution. As such, knowledge of this structuring is critical for the conservation and management of natural populations. Among marine mammals, many examples exist of species that enjoy a broad geographical distribution, yet are characterized by fine-scale population subdivisions. Coastal bottlenose dolphins have been studied extensively in a few regions globally, and these studies have highlighted a great diversity in both social strategies and demographic isolation. Here we use molecular genetic markers to examine the degree of population subdivision among three study sites separated by less than 250 km on Little Bahama Bank in the northern Bahamas. Mitochondrial DNA (mtDNA) sequence variation and microsatellite

Assessment of pinniped predation most often relies on analysis of the hard, undigested prey remains evident in faecal (scat) samples. For many prey species this method can yield valuable information on predator–prey interactions. For some genera, however, species diagnostic characteristics are lost during the process of prey digestion, thereby preventing morphological identification of fish prey species. Here, the feasibility of using faecal DNA to detect the presence of salmonids in pinniped scat samples and to distinguish reliably between sea trout Salmo trutta and Atlantic salmon S. salar was assessed. Novel salmonid mitochondrial DNA (mtDNA) primers were designed to amplify 162 bp of the 16S rDNA and a 327 bp section of the cytochrome b gene. Species-specific banding patterns were obtained by digestion of the cytochrome b PCR product with the restriction endonuclease AluI, and confirmed by the species-specific amplification of the 16S rDNA fragment from Atlantic salmon. Scats collected from captive grey seals Halichoerus grypus fed on known monospecific diets used to validate the PCR-RFLP assay indicated a probability of at least 95.8% (23 of 24 faecal extracts) of detecting salmonids using DNA extracted from the scat matrix. Implemented alongside conventional prey remains analyses, this technique presents a promising new method for examining prey composition and assessing pinniped predation on salmonids.

Noninvasive samples have proved useful in genotyping studies of free-ranging mammals. However, potential genotyping errors associated with such samples dictate the need for validation studies. This pilot study demonstrates the use of dolphin faeces in multilocus microsatellite genotyping studies. An empirical approach to calculating the rate of genotyping error was applied to data from matched pairs of blood or tissue and faecal samples from both captive and wild bottlenose dolphins. Microsatellite genotypes were assigned to dolphin faecal extracts with greater than 95% confidence by using a multiple tube approach, and at least two independent replicate genotypings.