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Map displaying the geomorphic features used to model sperm whale distribution in the Eastern Caribbean. Vessel tracks displayed in dark gray.
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Environmental variables are often the primary drivers of species' distributions as they define their niche. However, individuals, or groups of individuals, may sometimes adopt a limited range within this larger suitable habitat as a result of social and cultural processes. This is the case for Eastern Caribbean sperm whales. While environmental var...
Citations
... Several bathymetric and oceanographic covariates (Table 1) were obtained for each segment, based on their potential to influence sperm whale distribution (e.g. Waring et al., 1993;Praca et al., 2009;Pirotta et al., 2011;Tepsich et al., 2014;Mannocci et al., 2015;Breen et al., 2016;Claro et al., 2020;Vachon et al., 2022). Salinity was not included due to its close relationship with temperature in the Gulf Stream (Pauthenet et al., 2022) and its likely correlation with SST. ...
... Although not included in the spring DSM model, whales in the second cruise also tended to be detected in regions of low slope; the mean slope for detections made in spring (0.66 o ) was not significantly different to the mean slope in winter (0.61 o ) (t 236 = 1.43, p = 0.16). Although steep slope has been found to be a key driver for sperm whale presence in other regions (Praca et al., 2009;Mannocci et al., 2015;Tepsich et al., 2014), the MAPS surveys support the findings from other studies that have not found such a strong influence (Waring et al., 1993;Pirotta et al., 2011;Breen et al., 2016;Claro et al., 2020;Vachon et al., 2022). However, it should be noted that several sperm whales were detected during MAPS on the continental slope during off-effort surveying, and as relatively little dedicated on-effort surveying was dedicated to that region, more effort should be spent there before concluding that the region only supports low densities of sperm whales. ...
... In addition to latitude and longitude, several bathymetric and oceanographic parameters were used to generate the DSM (Table 1) and were selected on the basis of their potential to influence sperm whale distribution and their availability for the whole survey area. These parameters have been linked to sperm whale distribution in other studies, and included depth (Cañadas et al., 2005;Pirotta et al., 2011;Mannocci et al., 2017b;Pace et al., 2018;Pirotta et al., 2020), slope (Cañadas et al., 2005;Praca and Gannier, 2008;Pirotta et al., 2011;Pirotta et al., 2020), aspect (Pirotta et al., 2011;Pirotta et al., 2020), SST (Cañadas et al., 2005;Praca and Gannier, 2008;Pirotta et al., 2011;Pirotta et al., 2020), chlorophyll (Jaquet et al., 1996;Praca and Gannier, 2008;Mannocci et al., 2017b), distance to isobath (including 0, 200 and 1,000 m; Praca and Gannier, 2008;Pace et al., 2018;Sahri et al., 2020;Avila et al., 2022), distance to bathymetric features (such as canyons, escarpments, ridges, seamounts, shelves, slopes, terraces and troughs; Mannocci et al., 2017b;Sahri et al., 2020;Vachon et al., 2022), mixed layer thickness (Avila et al., 2022) and local currents (Vachon et al., 2022). Dynamic oceanographic parameters, such as SST, chlorophyll, depth of mixed layer and water speed/direction, can vary at timescales from seconds to decades. ...
... In addition to latitude and longitude, several bathymetric and oceanographic parameters were used to generate the DSM (Table 1) and were selected on the basis of their potential to influence sperm whale distribution and their availability for the whole survey area. These parameters have been linked to sperm whale distribution in other studies, and included depth (Cañadas et al., 2005;Pirotta et al., 2011;Mannocci et al., 2017b;Pace et al., 2018;Pirotta et al., 2020), slope (Cañadas et al., 2005;Praca and Gannier, 2008;Pirotta et al., 2011;Pirotta et al., 2020), aspect (Pirotta et al., 2011;Pirotta et al., 2020), SST (Cañadas et al., 2005;Praca and Gannier, 2008;Pirotta et al., 2011;Pirotta et al., 2020), chlorophyll (Jaquet et al., 1996;Praca and Gannier, 2008;Mannocci et al., 2017b), distance to isobath (including 0, 200 and 1,000 m; Praca and Gannier, 2008;Pace et al., 2018;Sahri et al., 2020;Avila et al., 2022), distance to bathymetric features (such as canyons, escarpments, ridges, seamounts, shelves, slopes, terraces and troughs; Mannocci et al., 2017b;Sahri et al., 2020;Vachon et al., 2022), mixed layer thickness (Avila et al., 2022) and local currents (Vachon et al., 2022). Dynamic oceanographic parameters, such as SST, chlorophyll, depth of mixed layer and water speed/direction, can vary at timescales from seconds to decades. ...
Acoustic surveys for sperm whales (Physeter macrocephalus) were conducted in the Mediterranean Sea in summer 2018 as part of the vessel-based component of the ACCOBAMS Survey Initiative (ASI). Equal-spaced zigzag transects provided uniform coverage of key sperm whale habitats and were surveyed using a towed hydrophone array deployed from a research vessel at speeds of 5-8 knots. A total of 14,039 km of tracklines were surveyed in the western basin, Hellenic Trench and Libyan waters, with an acoustic coverage of 10% realised for sperm whales. During these surveys, 254 individual sperm whales were detected on the trackline, with an additional 66 individuals off-track. Sperm whales were only seen ten times on-track, with an additional 16 off-track sightings. Estimates of slant range to echolocating whales were used to derive density estimates through both design- and model-based distance sampling methodologies. An acoustic availability of 0.912 (sd = 0.036) was derived from via published models. When correcting for availability bias, a design-based abundance estimates of 2,673 individuals (95% CI 1,739-4,105; CV = 0.21) was derived for the surveyed blocks, which incorporated most known sperm whale habitat in the Mediterranean Sea. The equivalent model-based estimate was 2,825 whales (2,053-3,888; CV = 0.16). Over 97% of detected whales were in the western basin, with highest densities in the Algerian and Liguro-Provencal Basins between Algeria and Spain/France. In the eastern basin, detections were sparse and concentrated along the Hellenic Trench. A density surface modelling (DSM) exercise identified location and benthic aspect as being the most instructive covariates for predicting whale abundance. Distance sampling results were used in a power analysis to quantify the survey effort required to identify population trends. In the most extreme scenario modelled (10% per annum decline with decennial surveys), the population could have dropped by 90% before the decline was identified with high statistical power. Increasing the regularity of surveys would allow population trends to be detected more expediently. Mediterranean sperm whales are listed as Endangered on the IUCN’s Red List and the need for urgent conservation measures to reduce injury and mortality remains paramount for this unique sub-population.
... trait strength of evidence references coda dialect excellent [20,[33][34][35][36]39] geographical extent excellent [20,29,39] small-scale distributions (10's km) good [25,44] large-scale movements (days-years) good [28,29] small-scale movements (hours) good [23,29] feeding success good [23] changes in feeding success with El Niño ok [23] reproductive rates ok [24] diving synchrony (babysitting) ok [26] homogeneity of social relationships within social units ok [26] duration of social relationships indication [26] diet indication [27] 1 ...
... The known Dominica whales were rarely found far from Dominica, and different islands had either very predominantly EC1 or very predominantly EC2 social units [29]. Differences in distribution between the clans could not be explained by differences in habitat features, but rather the vicinity of clans to particular islands themselves (most likely caused by the traditions of social units, closely linked to their clan membership) [44]. As a dramatic example, the waters off Martinique, just 30 km from EC1-dominated Dominica, contain almost entirely EC2 social units. ...
Sperm whale society is structured into clans that are primarily distinguished by vocal dialects, which may be symbolic markers of clan identity. However, clans also differ in non-vocal behaviour. These distinctive behaviours, as well as clan membership itself, are learned socially, largely within matrilines. The clans can contain thousands of whales and span thousands of kilometres. Two or more clans typically use an area, but the whales only socialize with members of their own clan. In many respects the closest parallel may be the ethno-linguistic groups of humans. Patterns and processes of human prehistory that may be instructive in studying sperm whale clans include: the extreme variability of human societies; no clear link between modes of resource acquisition and social structure; that patterns of vocalizations may not map well onto other behavioural distinctions; and that interacting societies may deliberately distinguish their behaviour (schismogenesis). Conversely, while the two species and their societies are very different, the existence of very large-scale social structures in both sperm whales and humans supports some primary drivers of the phenomenon that are common to both species (such as cognition, cooperation, culture and mobility) and contraindicates others (e.g. tool-making and syntactic language).
... Although not included in the spring DSM model, whales detected during Cruise 2 also tended to be detected in regions of low slope; the mean slope for detections made in spring (0.66 o ) was not significantly different to the mean slope in winter (0.61 o ) (t236 = 1.43, p = 0.16). Although high slope has been found to be a key driver for sperm whale presence in other regions (Praca et al. 2009, Mannocci et al. 2015, Tepsich et al. 2014, the MAPS surveys support the findings from other studies that have not found such a strong influence (Waring et al. 1993;Pirotta et al. 2011;Breen et al. 2016;Claro et al. 2020;Vachon et al. 2022). It is possible that the presence of warmer Gulf Stream waters over the regions of steepest slope in the study area did not provide ideal habitat for sperm whales. ...
... Many cetacean species are highly mobile and frequently move across arbitrary national or other jurisdictional boundaries. Even within a single species, we find variation in residency and ranging patterns (e.g., sperm whales, Vachon et al. 2022; killer whales, Ford 2019; common bottlenose dolphins (Tursiops truncatus), Oudejans et al. 2015). Yet, researchers in different regions of the world often have vastly different levels of access to resources (financial, technical, etc.), which can result in a patchy understanding of a species throughout its full range. ...
The world’s cetaceans (like most of biodiversity) are in crisis, and the need for well-informed conservation action has never been greater. Scientific advancements over the last few decades have provided much insight on the reproductive anatomy, physiology, and behavior of whales, dolphins, and porpoises. Our goal in this chapter is to link scientific findings to practical actions that will improve resilience and conservation prospects of cetaceans. We provide an overview of human activities and their impacts on cetacean reproduction and review the progress (or lack thereof) toward conserving species, with a particular focus on those for which sociality and culture may be important to population recovery. For all cetaceans, it is important to preserve or, where necessary and feasible, reestablish the ecological, demographic, and social conditions that allow the animals to reproduce successfully in their natural environment. The better we understand and integrate knowledge concerning cetacean reproductive health into conservation strategies, the better the chances of achieving species recovery, protecting biodiversity, and preventing future extinctions.
