Philip S. Hammond’s research while affiliated with University of St Andrews and other places

The Black Sea is a semi‐enclosed inland sea with an unevenly distributed extensive coastal shelf area and anoxic deep waters. It is inhabited by common and bottlenose dolphins, as well as harbour porpoises, all represented by local subspecies. Between September 2020 and October 2022, 19 F‐PODs deployed by research teams from Bulgaria, Georgia, Romania, Türkiye and Ukraine collected data on acoustic activity of Black Sea harbour porpoises. Strong seasonal and diel patterns were found, which varied in three regions. In the south‐eastern part of the Black Sea, harbour porpoise acoustic activity was higher from January to May, with a peak in April. This pattern agrees with the seasonal anchovy migration from the winter spawning grounds in warmer waters in the south‐eastern region to feeding grounds on the productive shallow north‐west shelf. The diel pattern showed strong nocturnal acoustic activity, which is consistent with anchovy vertical migration. Porpoises on the western side of the Black Sea exhibited a bimodal seasonal pattern in acoustic activity, with a larger peak in April and a smaller one in October. Diel activity was primarily nocturnal. On the north‐west shelf, harbour porpoise acoustic activity was mostly recorded during the warm period from April to October. The diel pattern showed activity mainly during daylight with two peaks: a smaller one approximately at dawn and a larger one at dusk. This pattern is similar to the vertical migrations of sprat. Overall, the results of the study were consistent with the prey being an important driver of seasonal and diel dynamics of harbour porpoise acoustic activity.

Understanding the drivers of population abundance and distribution is fundamental to ecology and key to informing conservation actions, particularly in endangered species like blue whales ( Balaenoptera musculus ). Historically, some Eastern North Pacific blue whales have aggregated in the Gulf of California (GoC) each winter. Using photo‐identification data collected around Loreto Bay from 1984 to 2020, we analyzed 453 sightings histories using mark‐recapture models. Estimated apparent survival (including permanent emigration) decreased from 0.991, 95% CI [0.977, 0.997] in 1985 to 0.889, 95% CI [0.807, 0.939] in 2019. The estimated number of whales using the study area declined from 96 whales, 95% CI [50, 254] in 2012 to 13 whales, 95% CIs [12, 23 and 12, 28] in 2018 and 2019. Abundance of the whole Eastern North Pacific population is slowly increasing, so our results likely reflect declining usage of the GoC. Linear models found a relationship between the number of whales in the GoC and the difference in sea surface temperature between the study area and the Costa Rica Dome wintering area, suggesting that environmental variation could explain variation in blue whale numbers in the GoC. These results highlight the importance of tracking population dynamics as changing environmental conditions affect the range and distribution of populations.

Statistical modelling of animal distributions has been widely applied to explain how mobile species use their habitats. The distribution of and habitat use by humpback whales Megaptera novaeangliae off the eastern coast of Brazil have previously been investigated by modelling visual survey data. Here, we modelled distribution in their breeding range using individual tracking data to compare ecological inferences with those from previous models from line transect data. A generalised estimating equation framework was used to model the tracking data and pseudo-absences as functions of spatial covariates. Covariates considered were latitude and longitude, sea surface temperature (SST), current and wind speeds near the surface, distances to shelf-break and the coast, sea bottom depth and slope, and a factor variable representing ‘shelter’. Two modelling exercises were developed: a habitat use model (HUM) and a distribution model (DIM). Covariates retained in the selected HUM were SST, distance to coast and shelf-break, current and wind speeds and shelter. Covariates retained in the selected DIM were latitude/longitude, current speed and distances to shelf-break and coast. The modelled relationships between whale occurrence and environmental covariates using tracking data were similar to those using line transect data. Distribution maps were also similar, supporting higher densities around the Abrolhos Archipelago and to its south. We showed that habitat use and distribution of this population in the area could be similarly inferred by modelling either line transect or tracking data. Using these 2 approaches in conjunction can strengthen the understanding of important ecological aspects of animal populations.

The large-scale international survey SCANS-IV from summer 2022 is complementing previous surveys (SCANS 1994, SCANS-II/CODA 2005/2007, SCANS-III 2016). These data provide information on changes in the abundance and distribution of the most abundant cetacean species over a considerable period of almost three decades. This enables an assessment of the conservation status and is thus an important basis for establishing effective conservation measures. The SCANS-IV project is supported by the governments of Denmark, France, Germany, the Netherlands, Spain, Sweden, Portugal and the United Kingdom. SCANS-IV, in which teams of observers in eight aircraft and on one research vessel were deployed simultaneously in a study area from southern Norway to the Strait of Gibraltar in Portugal, investigated the European Atlantic in the summer of 2022 with the largest search effort to date. Over a period of six weeks, an area of 1.7 million km² was covered and a distance of 75,000 km was travelled along transects.

Some dolphin species produce signature whistles, which may allow the identification of individual dolphins using passive acoustic monitoring (PAM). Identifying individuals by their sounds may enhance the opportunities for monitoring and addressing biological and ecological questions about these species. Here, we explored the potential of signature whistles to investigate ecological aspects of a resident bottlenose dolphin population. Using a limited data set, with few individuals recognized by signature whistles, combined with spatial capture‐recapture (SCR) methods, we investigated how effective such approach is describing spatial use patterns and estimating density for this population. The data were collected using 4–6 stationary bottom‐moored recorders. Since only eight signature whistles were identified, our density estimate may represent a subset of the entire population. However, even with only a few signature whistles identified, our results confirmed the center of the core area used by these dolphins as the area with the highest encounter probability. In addition, our results provided evidence that these dolphins have the same spatial use pattern at night as during the day. This study shows that SCR analysis of signature whistle data can improve our ecological knowledge and understanding of dolphin populations.

Kelp gulls (Larus dominicanus) commonly feed on the skin and blubber of surfacing southern right whales (SRW, Eubalaena australis) in the near shore waters of Península Valdés (PV), Argentina. Mothers and especially calves respond to gull attacks by changing their swimming speeds, resting postures and overall behaviour. Gull-inflicted wounds per calf have increased markedly since the mid-1990s. Unusually high mortality of young calves occurred locally after 2003, and increasing evidence points to gull harassment as a factor contributing to the excess deaths. After leaving PV, calves undertake a long migration with their mothers to summer feeding areas; their health during this strenuous exertion is likely to affect their probabilities of first-year survival. To explore the effects of gull-inflicted wounds on calf survival, we analysed 44 capture-recapture observations between 1974 and 2017, for 597 whales photo-identified in their years of birth between 1974 and 2011. We found a marked decrease in first-year survival associated with an increase in wound severity over time. Our analysis supports recent studies indicating that gull harassment at PV may impact SRW population dynamics.

The size of the Baltic Proper subpopulation of Harbour Porpoises is estimated to be fewer than 250 mature animals. A continuing decline in mature animals can be inferred based on information on the number of animals bycaught in fishing gear compared to the potential growth rate of the Baltic Proper subpopulation. Other threats to the reproduction and survival of Harbour Porpoises, including contaminants, noise, and prey depletion, are also ongoing for this subpopulation. All mature individuals of the Baltic Proper subpopulation belong to one subpopulation, which cannot be rescued by immigration of individuals from another subpopulation. Thus, the subpopulation meets criterion C2a(ii). This subpopulation was listed as Critically Endangered (C2a(ii)) on the Red List in 2016 and it remains Critically Endangered (C2a(ii)) in this updated assessment.

Little Bahama Bank in the northern Bahamas supports several populations of bottlenose dolphins ( Tursiops truncatus ). We provide the first estimates of birth rate and age-class-specific apparent survival rates for the local South Abaco population using data from a long-term (1997–2014) photo-identification (photo-ID) study and use the estimated life history parameters in a population viability analysis (PVA) to predict future population trends. Hurricane events are predicted to become more intense due to climate change but knowledge of how hurricanes may impact cetacean populations is limited. Little Bahama Bank is subject to hurricane activity, so we also investigate the potential impact of hurricanes on calf, juvenile and adult survival. Photo-ID data confirmed the existence of a core adult population with relatively high site fidelity in South Abaco, but also evidence of transient animals. Estimated annual birth rate was 0.278 (95% CI: 0.241–0.337). We found strong support for a decline in apparent survival for all age-classes. Estimated survival declined by 9% in adults (0.941 in 1998, to 0.855 in 2013), 5% in juveniles (0.820 in 2000, to 0.767 in 2013) and 36% in calves (0.970 in 1997, to 0.606 in 2013). Evidence that survival was influenced by repeated hurricane activity leading to increased mortality and/or emigration was stronger for calves and juveniles than for adults. PVA simulations of an assumed isolated South Abaco population showed that declines would lead to extinction within decades, even under the most optimistic scenario. Future work should focus on establishing if South Abaco is part of natural source–sink metapopulation dynamics on Little Bahama Bank by assessing trends in abundance in local populations and establishing how they interact; this will be important for assessing their conservation status in a potentially increasingly changing environment.