We studied the sperm whale Physeter macrocephalus in the Colombian Caribbean by combining data from our offshore surveys of behaviour, encounter rate, group structure and density with data from the literature. We describe for the first time the potential distribution of sperm whales in the Colombian Caribbean, using sighting and acoustic data obtained during our surveys, published information, and opportunistic encounters during 1988–2020. We conducted surveys on seismic vessels over 703 days during 2011–2016, covering an area of 68,904 km2. We recorded 98 individuals in a total of 50 groups, a density of 1.42 individuals per 1,000 km2. To determine the potential distribution of the species, we built Maxent models with uncorrelated environmental variables at five depths (from the surface to c. 2,000 m). The model for 1,000 m depth had the best performance, with areas of high probability of occurrence of sperm whales in the south and north-east Colombian Caribbean over the shelf break to waters up to c. 3,000 m deep, at a median distance of 107 km from the coast, and near the Archipelago of San Andrés, Old Providence and Saint Catherine in the north-west. This area may be an important tropical habitat for sperm whales, in which they socialize, rest, breed and feed. Our study underlines the importance of monitoring marine mammals offshore and describes the potential distribution of sperm whales in the Colombian Caribbean, supporting conservation actions for this Vulnerable species, which is currently facing several threats in this region.

The Earth's atmosphere and the Earth's magnetic field protects local life by shielding us against Solar particle flows, just like the sun's magnetic field deflects cosmic particle radiation. Generally, magnetic fields can affect terrestrial life such as migrating animals. Thus, terrestrial life is connected to astronomical interrelations between different magnetic fields, particle flows and radiation. Mass strandings of whales have often been documented, but their causes and underlying mechanisms remain unclear. We investigated the possible reasons for this phenomenon based on a series of strandings of 29 male, mostly bachelor, sperm whales (Physeter macrocephalus) in the southern North Sea in early 2016. Whales’ magnetic sense may play an important role in orientation and migration, and strandings may thus be triggered by geomagnetic storms. This approach is supported by the following: (1) disruptions of the Earth's magnetic field by Solar storms can last about 1 day and lead to short-term magnetic latitude changes corresponding to shifts of up to 460 km; (2) many of these disruptions are of a similar magnitude to more permanent geomagnetic anomalies; (3) geomagnetic anomalies in the area north of the North Sea are 50–150 km in diameter; and (4) sperm whales swim about 100 km day−1, and may thus be unable to distinguish between these phenomena. Sperm whales spend their early, non-breeding years in lower latitudes, where magnetic disruptions by the sun are weak and thus lack experience of this phenomenon. ‘Naïve’ whales may therefore become disoriented in the southern Norwegian Sea as a result of failing to adopt alternative navigation systems in time and becoming stranded in the shallow North Sea.

The stomach contents of a male sperm whale, Physeter macrocephalus, stranded on Forte dei Marmi beach (Italy, Ligurian Sea) were examined. Food items consisted exclusively of cephalopod hard parts: 233 upper and 291 lower beaks and one fish eye lens. The majority of the identified cephalopod beaks belonged to Histioteuthis bonnellii, but a few beaks of Galiteuthis armata and Octopoteuthis sp. were also found. A new beak size–cephalopod size regression was created for H. bonnellii with specimens caught in the study area. Reconstructed prey weight for the species was much higher when applying this new regression instead of Clarke's, highlighting the need for area- and species-specific regressions for dietary studies. Our analysis represents the second report on the stomach contents of sperm whales from the Mediterranean and the first available information for the Western basin.

Little is known about the movements of male sperm whales, Physeter macrocephalus, in the North Atlantic. Recoveries of traditional harpoons and tags during commercial whaling indicated movements from Nova Scotia to Spain and from the Azores to Iceland and Spain. We compared collections of photo-identification images from different areas using the North Atlantic and Mediterranean Sperm Whale Catalogue and the Eurphlukes Phlex/Match programs. The largest collections of identified males (number of individuals, start and end date for data collection shown in parentheses) are for the Azores (297, 1987–2008), Andenes (375, 1988–1996 and 2008), Tromsø (84, 2005–2008). There were six matches between Andenes and Tromsø (~25 nm), with three of these re-sighted in multiple years and three photo-identification matches from the Azores to Norway (~2400 nm). In all cases individuals first photographed in the Azores (in 1993, 1999 and 2003) were matched to images collected later in Tromsø (in 2007 and 2008). In 1997 a photo-identification image from Andenes matched a male stranded on the west coast of Ireland. No matches were made to images in smaller collections from Iceland, Nova Scotia, Greenland, Dominica, Guadeloupe, Gulf of Mexico and the Mediterranean. These findings show the value of data collected from whale watching vessels and the importance of collaboration between groups to allow investigation on an ocean basin scale. It is hoped that with the coordinated collection of more images from around the Atlantic, further insight might be gained into the movements of these widely ranging animals.

Sperm whales (Physeter macrocephalus) have one of the most extensive global distributions of any cetacean, but distribution and movement patterns vary significantly between sexes. Adult male sperm whales are predominantly solitary and have an expansive distribution, whereas females and their offspring typically form groups of both sexes, remaining in the tropics and sub-tropics throughout the year. Here we present observations and photographs from a rare winter sighting of a group of female and immature sperm whales near Koniuji Island, in the Central Aleutians, in the high-latitude waters of the Bering Sea. This sighting is consistent with historic whaling catches of sperm whales of both sexes, including pregnant females, above 50°N in the North Pacific, but no groups of females and immatures have been observed in ten years of summer sighting surveys in the Aleutian Islands and Bering Sea region, despite regular sightings of adult males. We discuss possible reasons for the absence of recent sightings of these mixed schools.

Information on cetaceans off Gabon in tropical West Africa is summarized from boat-based surveys carried out between 7 March and 7 August 2009. Thirteen cetacean species were positively identified comprising two baleen whale species, one sperm whale species and ten species of delphinid. Bryde's whale (Balaenoptera brydei) and humpback whale (Megaptera novaeangliae) were the most frequently encountered species. Cetaceans were found throughout a range of sea surface temperature between 20.5°C and 27.5°C and a wide range of depths with the majority of effort and sightings occurring seaward of the shelf break. Of particular interest from the study were the following: (1) Gabonese waters have a broad cetacean diversity, especially with a large and diversified delphinid community in the northern part of the study area; (2) the variations in oceanographic conditions within Gabonese waters are likely to result in a temporal variation in species composition; (3) the sightings of Atlantic spotted dolphin (Stenella frontalis) are the first at-sea sightings confirmed for these waters, although not unexpected given their distribution and abundant presence in surrounding waters; and (4) the poorly known Clymene dolphin (Stenella clymene) was sighted on four occasions in deep oceanic waters and was the most abundant cetacean. These are the first confirmed records of Clymene dolphins in Gabonese waters.

Sperm whale, Physeter macrocephalus, distribution was compared to acoustic backscatter observations in the Gulf of California. Forty-three sperm whale groups, totalling 813 individuals, were encountered during 28 observation days. Sperm whales occurred over deep waters (mean depth = 659 m, range: 300–1800 m). A significant correlation was found between the whales' maximum depth of dive and depth of the acoustic scattering layer (N = 36, r2 = 0.944, P = 0.000). We observed sperm whales dive to the scattering layer and then surface with prey in their jaws: jumbo squid, Dosidicus gigas (10 events) and unidentified fish (one event). The average depth of sperm whale foraging dives to the scattering layer was 342 m, the average diving time was 23 minutes, and the average surface interval between foraging dives was 6 minutes. Sperm whales spent 75% of their time diving and 25% on the surface. Swimming speed at the surface was slower when whales reached scattering layers during a dive (2.4 km/h) compared to dives when no scattering layer was reached (8.9 km/h). Our results establish a direct link between sperm whale distribution and presence of its prey in the Gulf of California.

The age of 86 individuals derived from groups of female sperm whale Physeter macrocephalus involved in three mass strandings on the north and west coasts of Tasmania in 1998 was determined from the number of dentinal growth layer groups in the teeth of individuals. Dorsal total lengths were also measured. Ages of females ranged from 0.75 to 64 years, with the majority (77%) aged between 20 and 45 years. Total lengths of female sperm whales ranged from 417–1200 cm, with 68% of females 1050–1200 cm long. Constraints associated with the age structure observed in this study and the representativeness of the age structure to that of the greater population are discussed. In an effort to assess the effects of underestimation of age estimates on age-specific demographic parameters, a model simulating changes in age structure as a result of tooth wear was developed and the resulting survival rates compared to those derived from the original age structures of the samples. Survival did not change significantly between the modelled and original age structures. Also, the survival rate calculated from Australian mature female sperm whales was compared to that calculated from sperm whales caught in whaling operations from Japanese waters. Australian mature female sperm whales demonstrated significantly higher survival rates (mean=0.905±0.046 SD range: 0.856–0.986) than mature females from Japanese waters (mean=0.885±0.034 SD; range=0.859–0.970), possibly the reflection of higher fishing mortality on the Japanese whales. Growth equations using Gompertz and von Bertalanffy models were calculated for female Australian sperm whales and compared. Both models described growth in female sperm whales similarly. Changes in the demographic parameters of sperm whales with the cessation of whaling may be reflected in the growth rates of individuals and as such, these equations may provide a useful tool for monitoring continuing changes in the demographic parameters of this species. Without long-term mark–recapture studies on sperm whales in this region, the frequent stranding of sperm whales in south-eastern Australia provides an important opportunity to collect data on the life history and demography of this species.