Sea turtle populations have significantly declined in recent years due to anthropogenic causes. Historical stranding records in the Canary Islands archipelago (Spain) reveal a high frequency of Caretta caretta and Chelonia mydas strandings. Our study aims to comprehensively characterize and explore these stranding records. Additionally, we have investigated the interactions between sea turtles and the island's professional fishers, seeking insights from small-scale artisanal fishers to understand the current state of sea turtle populations. The results have shown that Tenerife stands out with the highest number of sea turtle strandings, recording 1875 strandings over a span of 23 years. The primary cause of sea turtle stranding's is the interaction with fishing gear, specifically nets and hooks. Moreover, our research has highlighted the need for improved knowledge and training on how to handle stranded sea turtles within the fishing sector. Consequently, raising awareness and implementing conservation plans for sea turtle populations in Tenerife is of outmost importance in addressing and improving the current situation.

We report the first record of Ramari's beaked whale (Mesoplodon eueu) from the temperate Southwestern Atlantic. Our analysis is based on an adult female and a plausibly associated calf/juvenile that stranded on the coast of Canelones Department, Uruguay. The species of the two individuals was identified via a combination of morphometric and molecular mitochondrial data and provide new insights into the Ramari's beaked whale, including previously unknown polymorphisms in the mitochondrial genome and a re-estimated date of divergence from Mesoplodon mirus at 2.5902 Mya.

Changes in abundance and distribution of marine top predators can indicate environmental change or anthropogenic pressure requiring management response. Here, we used an extensive dataset (21 years) to conduct a spatial and temporal analysis of grey seal strandings in Cornwall and the Isles of Scilly, close to the southern edge of the breeding range of the species. A total of 2007 strandings were reported from 2000 to 2020, increasing by 474% from 35 to 201 individuals per year during this period. The continued rise in strandings was consistent across all life stages and timeframes (5, 10 and 20 years), underpinning the suggestion of increasing abundance in the region. The observed seasonality differed by life stage, coinciding with the increased presence of animals near the coast for key life phases such as breeding, moulting and pupping. Strandings are widely distributed across the coast of Cornwall and the Isles of Scilly; however, most strandings were recorded on the north coast of Cornwall (70%) where major pupping and haul out sites are found. Despite hosting several pupping and haul out sites, a small proportion was recorded on the Isles of Scilly (5%) where it is thought that strandings are particularly underreported. Describing baselines in magnitude of strandings and life-stage compositions across space and time allows future deviations in frequency, demographic composition or spatial distribution to be detected and investigated. We demonstrate the utility of long-term citizen science data to provide valuable and cost-effective information on the distribution and abundance of a highly mobile marine mammal.

The endemic Caspian seal Pusa caspica breeds on land-fast ice or stable drift ice in the northern Caspian Sea. Breeding has rarely been reported in the ice-free south-eastern Caspian Sea. Five carcases of white-coat Caspian seal pups were recovered from the southern Caspian Sea, Iran, during 2019–2022. From survey interviews, two white-coat Caspian seal pups were also observed in Amirabad and between Ghorogh and Rudsar. These records represent very late pupping dates compared to normal pupping periods. Coastal Iran should be surveyed annually for Caspian seal pups to determine frequency of breeding and areas of importance identified in the Iran Caspian Seal Action Plan.

The International Whaling Commission (IWC) currently uses imprecise indicators of death to evaluate the welfare consequences of whaling. A recent independent meeting of animal welfare scientists proposed a series of tests to determine the states of sensibility/insensibility/death of whales. As a precursor to assessing these tests in the field, conjoint analysis was used to evaluate expert opinion and to identify tests deemed most suitable for establishing insensibility and death. The results of this study indicated that experts considered measurement of breathing rate, cardiac activity, coordinated swimming and ocular temperature to be among the most useful for determining that animals were not dead. Furthermore, experts considered that judgements that an animal was dead should be made only after application of a series of different tests. The tests identified may be valuable for assessing stranded whales or animals taken as part of whaling operations.

The stranding of cetaceans raises significant welfare and associated logistical issues. A survey of opinions on euthanasia methods based on the recommendations of an International Whaling Commission (IWC) workshop was conducted. Descriptive statistics showed that the workshop recommendations were generally supported and understood, and these included the use of specific euthanasia techniques, but important barriers to adherence were identified, including lack of governmental support, lack of resources, and lack of experienced or trained personnel. Conjoint analysis of factors identified that ‘time to death’ was considered the most important determinant of welfare outcome. In view of the findings of this study, it is recommended that the IWC should consider creating a training programme for responders (both veterinary and non-veterinary) to ensure that trained personnel are available who can implement timely and tailored euthanasia techniques, if required, when strandings occur. Further research on this topic is also advocated to ensure a better understanding of what is being applied in different nations.

Sowerby's beaked whale is a deep-diving cetacean species specialized to live in the deep waters of the North Atlantic, including offshore Irish waters. Sightings of Sowerby's beaked whales in this area are infrequent and a substantial increase in our knowledge of their presence comes from recent static acoustic monitoring (SAM) and passive acoustic monitoring (PAM). However, most information on this species has been derived from stranding records, which provide opportunistic insights into this elusive species' cryptic life history. Here we report on the live stranding of a 1200 mm long neonate and an adult 5 m female Sowerby's beaked whale in July 2015 and on the stranding of a 4.9 m pregnant female in September 2020 with a 495 mm long male foetus in the south-west of Ireland. These stranding events provide an important insight into the reproductive life history of this species and provide further evidence that Sowerby's beaked whales calve in offshore Irish waters.

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.

Cetaceans of Morocco have been poorly studied to date, and only sporadic information comes from scientific cruises for this group. In an attempt to learn more on the occurrence, distribution and relative abundances of cetaceans in Morocco, a stranding database was reconstructed from various sources (stranding reports from state agencies and newspaper clippings). This inventory documented 205 cases of stranding between 1980 and 2009. Most of the strandings and most confirmed cases of interactions with human activity (fishing, for dolphins; collisions, for whales) were reported in the Strait of Gibraltar and adjacent areas from the Atlantic and the Mediterranean. Sixteen species were identified from the stranding database, of which seven species were the most abundant. These were striped dolphins, common dolphins, bottlenose dolphins, fin whales, sei whales, sperm whales and long-finned pilot whales. The fin and sei whales were present throughout the year and stranding of common and striped dolphins were minimal between September and December. The fin, sei and sperm whales seem to be present in Moroccan waters at birth and at different stages of their life cycle. Establishing an observation network of sufficient and sustainable density in Morocco is the most likely way to collect robust data for the calculation of credible population indicators for cetaceans. Monitoring will certainly improve through better collaboration among Moroccan institutions and a greater awareness in Moroccan civil society of environmental issues.

Recent observations of unusual mass stranding and mortality of two Indian Ocean crustacean species, the swimming crab Charybdis smithii and the mantis shrimp Natosquilla investigatoris, are documented and analysed. Strandings of C. smithii were observed for the first time in the equatorial Indian Ocean, the main area of its pelagic distribution. Strandings of mantis shrimps are reported from throughout the western Indian Ocean; occurrences of mass stranding in the Maldives Archipelago mark an extension of the known range of N. investigatoris into the central Indian Ocean. Mortality of crabs probably represents a ‘catastrophic event’. In contrast, mantis shrimp strandings, which were always associated with a sudden increase of its biomass (‘blooms’), are apparently post-reproduction mortalities indicating potential semelparity for this species.

The stalked barnacle Dosima fascicularis is reported from Uruguayan waters for the first time based on stranded specimens. It is suggested that the Subtropical Front is the main area of occurrence of D. fascicularis in the South Atlantic and its occurrence on the Uruguayan coast was found to be sporadic and mainly related to singular atmospheric and oceanographic factors that cast ‘blue plankton’ ashore (e.g. easterly and south-easterly winds, and prevalence of tropical waters).

Western Australia has an extensive coastline extending 12889 km (excluding islands) from latitude 35 degrees in the south to 14 degrees in the north. The extensive coastline intersects the distribution of many species of beaked whale. A total of 74 Ziphiidae were recorded as stranded along the Western Australian coast between 1940 and 2010 (70 years). Ten of the 21 species of beaked whales currently recognized taxonomically worldwide have been observed in Western Australia with True's beaked whale Mesoplodon mirus and Shepherd's beaked whale Tasmacetus shepherdi recorded more than elsewhere in Australia. Western Australia has the highest species diversity (10) of beaked whale strandings compared to other Australian states and regions. Gray's beaked whale, Mesoplodon grayi, was the most commonly reported species (33 records) and had the largest mass stranding group size (seven) of the beaked whales stranded in Western Australia. The records presented in this paper confirm the distribution of Arnoux's beaked whale Berardius arnuxii, strap-toothed beaked whale Mesoplodon layardii, Shepherd's beaked whale, Blainville's beaked whale Mesoplodon densirostris in Western Australian waters. The records presented of True's beaked whale confirm its presence in Australian waters, with Western Australia a possible key location for this species. Factors causing strandings and death should be investigated in future wherever possible, particularly the rostral injuries reported for six beaked whales. Beaked whale species identification should be confirmed through genetic analysis in future to maximize certainty of species identification.

A total of 209 strandings of sea turtles (152 loggerhead turtles Caretta caretta, 42 green turtles Chelonia mydas, 15 unidentified) were recorded during the period 1984–2011 along the coasts of Rhodes (Aegean Sea, Greece). The proportion of dead to live individuals was different in the two species. Stranded Caretta caretta were larger than Chelonia mydas. The size range of stranded green turtles, usually juveniles, appeared to increase since 2000, including the largest specimens ever observed in Greek waters. For both species, a tendency to strand more frequently on the west coast of the island, along fishing ground areas, was noted. The higher incidence of loggerhead turtle strandings was observed in summer, while more green turtle strandings were documented in winter. Factors involved in the increased trend of stranding records of both species, along with the acceleration of this phenomenon in the last decade, are discussed. Data from Rhodes provide evidence that human activities detrimentally affect mainly larger-sized loggerhead turtles living in shallow waters.

A dead dolphin found on Bonaire in August 2011 is identified as adult Fraser's dolphin Lagenodelphis hosei, a new species for the Dutch Caribbean. A first closer examination showed a collapsed lung, stomach parasite infection and abundant mouth ulceration as indications of its health status. The animal was relatively fresh and did not die very long before it was found. Like more often with stranded deep diving cetacean species within the area, remnants of crustacean were found in its beak indicating recent foraging.

On 29 February 2011 a strap-toothed beaked whale Mesoplodon layardii stranded in the mouth of the Pyin Sa Lu and Thaung Du rivers bordering the northern Indian Ocean in Myanmar at approximately 16°N of the equator. This stranding occurred more than 5000 km from the normal distribution of the species in cold temperate waters below 35°S. Mesoplodonts are the most poorly known of all cetaceans; however, due to the large number of documented strandings and the species' distinctive appearance, the distribution of strap-toothed beaked whales is probably the best known of the genus. For these reasons, the Myanmar stranding is believed to be an anomalous extra-limital occurrence rather than an extension of the species' normal distribution.

I present the first documented record of a dead gray whale (Eschrichtius robustus) discovered at Playas Negras, La Union on the Pacific coast of El Salvador, Central America, on 21 July 2010. The stranded specimen also represents the southernmost record of this species anywhere. No necropsy was performed thus the cause of death is unknown.

The pygmy killer whale (Feresa attenuata) is a small cetacean that can be found worldwide in offshore tropical and warm temperate waters. Most information about F. attenuata has been attributed to stranded or accidentally caught specimens and rarely through observation of free-ranging individuals. There is very little information about this cetacean in South Atlantic waters. In Brazil, only two confirmed strandings and four sightings have been published up to date. In this study we present the third confirmed stranding of the pygmy killer whale on the Brazilian coast. The current and previous records of Brazilian specimens suggest that F. attenuata may eventually use the continental shelf to feed and rest, principally in some areas of the Brazilian waters where this oceanographic feature is narrow.

A juvenile female Commerson's dolphin (Cephalorhynchus commersonii) was found dead stranded 15 km north of Necochea (38°38′S 058°53′W), Buenos Aires Province, Argentina, approximately 470 km north of the normal range for this species. The animal appeared to be emaciated and granular nodules were found throughout both lungs, but the cause of death is unknown. Analyses of mtDNA sequences suggest the individual could have been a vagrant from any of the populations studied south of the stranding location.

The first mass stranding of Risso's dolphins Grampus griseus on the Peruvian coast occurred on Pozo de Lizas Beach (17°42′30.3″S 71°18′48.7″W), port of Ilo, Department of Moquegua, southern Peru, between 7 and 8 June 2007. At least 14 Risso's dolphins were stranded along 1.5 km of beach. Just 7 of them could be sized and 8 sexed; this group was composed of 7 males and a single female plus a juvenile of undetermined sex. Mean standard body length of the males was 299.67 cm (SD: 9.91 cm, range: 292–317 cm) and the female measured 289 cm. The entire group, including four individuals found alive, was illegally butchered by the local people to use the meat as food, while other remains were used as bait in the pelagic long-line fishery. This record fills a distributional gap of about 1000 km in the known distribution of the species between central Peru and northern Chile. Additional education is required for improved conservation strategies in future cetacean strandings.