Species can base their impression of themselves on the number of sensory neurons they have and their IUCN level

Humans have the most sensory neurons of any terrestrial species, 18.83B, with more than twice as many as the runner up western gorilla. There are three aquatic species with more than humans and seven more with more than the western gorilla. The killer whale with more than twice as many as humans, long-finned and short-finned pilot whale with a little less than twice humans. With that many sensory neurons it would be assumed that those would be the species with the most emotional disturbance from anthropogenic influence. There is no data on killer whale endangerment, and both long and short finned pilot whales are LC, ranking them 23rd and 24th most disturbed species. It is important for us to consider what the species means to them in evaluating what species we should care about, it would be beneficial to base that on what species care about themselves the most.

The primary visual cortex of Cetartiodactyls: organization, cytoarchitectonics and comparison with perissodactyls and primates

Cetartiodactyls include terrestrial and marine species, all generally endowed with a comparatively lateral position of their eyes and a relatively limited binocular field of vision. To this day, our understanding of the visual system in mammals beyond the few studied animal models remains limited. In the present study, we examined the primary visual cortex of Cetartiodactyls that live on land (sheep, Père David deer, giraffe); in the sea (bottlenose dolphin, Risso’s dolphin, long-finned pilot whale, Cuvier’s beaked whale, sperm whale and fin whale); or in an amphibious environment (hippopotamus). We also sampled and studied the visual cortex of the horse (a closely related perissodactyl) and two primates (chimpanzee and pig-tailed macaque) for comparison. Our histochemical and immunohistochemical results indicate that the visual cortex of Cetartiodactyls is characterized by a peculiar organization, structure, and complexity of the cortical column. We noted a general lesser lamination compared to simians, with diminished density, and an apparent simplification of the intra- and extra-columnar connections. The presence and distribution of calcium-binding proteins indicated a notable absence of parvalbumin in water species and a strong reduction of layer 4, usually enlarged in the striated cortex, seemingly replaced by a more diffuse distribution in neighboring layers. Consequently, thalamo-cortical inputs are apparently directed to the higher layers of the column. Computer analyses and statistical evaluation of the data confirmed the results and indicated a substantial correlation between eye placement and cortical structure, with a markedly segregated pattern in cetaceans compared to other mammals. Furthermore, cetacean species showed several types of cortical lamination which may reflect differences in function, possibly related to depth of foraging and consequent progressive disappearance of light, and increased importance of echolocation.

Massed Strandings of Whales and Dolphins – Effects of Wind, Waves and Tides.

We examined125 mass-stranding events of cetaceans (>=10 individuals) on New Zealand shores over the past 40 years. The wind, waves, wave refraction, shore slopes and tides at the dates and locations of these events were considered. The mass-strandings involved 10 different species, but by far the most common involved the Long-finned Pilot Whale, Globicephala melas. Our hypothesis is that mass-stranding is a three-stage process. The first stage is when an animal becomes ill, its body may become bloated and float on the surface, and the wind and waves may drive it ashore. We assume the second stage is that the dying or dead body may be accompanied by pod members as a result of strong social bonds. The third stage involves the tides and the beach slope. If these are of sufficient amplitude, the nearby attendees will quickly become stranded in the intertidal of a gently sloping beach as the water level falls. We have evaluated evidence for the first and third stages. In the overwhelming majority (91%) of the mass-strandings (omitting events inside estuaries), the available data showed that wind and waves would drive floating objects (bodies) toward the stranding site. Examination of the nearshore slopes and the tide ranges showed that the vast majority of the stranding sites were slowly shelving beaches where the tides would retreat rapidly over 10s of metres. These 2 results are even more pronounced if only Pilot Whale mass strandings are considered.

Trait-mediated shifts and climate velocity decouple an endothermic marine predator and its ectothermic prey

Climate change is redistributing biodiversity globally and distributional shifts have been found to follow local climate velocities. It is largely assumed that marine endotherms such as cetaceans might shift more slowly than ectotherms in response to warming and would primarily follow changes in prey, but distributional shifts in cetaceans are difficult to quantify. Here we use data from fisheries bycatch and strandings to examine changes in the distribution of long-finned pilot whales (Globicephala melas), and assess shifts in pilot whales and their prey relative to climate velocity in a rapidly warming region of the Northwest Atlantic. We found a poleward shift in pilot whale distribution that exceeded climate velocity and occurred at more than three times the rate of fish and invertebrate prey species. Fish and invertebrates shifted at rates equal to or slower than expected based on climate velocity, with more slowly shifting species moving to deeper waters. We suggest that traits such as mobility, diet specialization, and thermoregulatory strategy are central to understanding and anticipating range shifts. Our findings highlight the potential for trait-mediated climate shifts to decouple relationships between endothermic cetaceans and their ectothermic prey, which has important implications for marine food web dynamics and ecosystem stability.

Cetacean strandings along the German North Sea coastline 1604–2017

The occurrence of 19 cetacean species along the German North Sea coastline as well as the lower reaches of the major rivers discharging into the German Bight is reviewed for the period 1604–2017 based on records of dead animals, either stranded dead or put to death. The harbour porpoise (Phocoena phocoena) is considered the most abundant and only native species in German coastal and riverine waters. Based on written sources its presence can be traced back to at least 1651, although with statistical data only available from 1990. Finds of further 18 species have been documented: white-beaked dolphin (Lagenorhynchus albirostris), bottlenose dolphin (Tursiops truncatus), Atlantic white-sided dolphin (Lagenorhynchus acutus), common dolphin (Delphinus delphis), striped dolphin (Stenella coeruleoalba), Risso's dolphin (Grampus griseus), long-finned pilot whale (Globicephala melas), killer whale (Orcinus orca), beluga whale (Delphinapterus leucas), narwhal (Monodon monoceros), Sowerby's beaked whale (Mesoplodon bidens), northern bottlenose whale (Hyperoodon ampullatus), sperm whale (Physeter macrocephalus), minke whale (Balaenoptera acutorostrata), sei whale (Balaenoptera borealis), fin whale (Balaenoptera physalus), blue whale (Balaenoptera musculus) and humpback whale (Megaptera novaeangliae). This review corrects several false species assignments earlier introduced in literature based on incorrect scientific or ambiguous German vernacular names and recovers lost records of beluga whale, northern bottlenose whale, sperm whale and fin whale.

Cetacean Research and Citizen Science in Kenya

In 2011, several non-governmental and government agencies established the Kenya Marine Mammal Network (KMMN) to provide a platform for the consistent collection of data on marine mammals along the Kenyan coast, identify areas of importance and engage marine users and the general public in marine mammal conservation. Prior to the KMMN, relatively little was known about marine mammals in Kenya, limiting conservation strategies. The KMMN collects data nationwide through dedicated surveys, opportunistic sightings and participative citizen science, currently involving more than 100 contributors. This paper reviews data on sightings and strandings for small cetaceans in Kenya collated by the KMMN. From 2011 to 2019, 792 records of 11 species of small cetaceans were documented. The most frequently reported inshore species were the Indo-Pacific bottlenose dolphin and Indian Ocean humpback dolphin. Offshore species, included killer whales, short-finned pilot whale and long-snouted spinner dolphin. Indo-Pacific bottlenose dolphins, long-snouted spinner dolphins, striped dolphins and Risso’s dolphins were recorded through stranding reports. The efforts of the KMMN were disseminated through international meetings (International Whaling Commission, World Marine Mammal Conference), national status reports, outreach and social media. Data has also supported the identification of three IUCN Important Marine Mammal Areas and one Area of Interest in Kenya. Further research is needed to improve estimates of cetacean abundance and distribution, particularly in unstudied coastal areas, and to assess the extent of anthropogenic threats associated with fisheries, coastal and port development, seismic exercises and unregulated tourism. The expansion of the network should benefit from the participation of remote coastal fishing communities, government research agencies, tourism and seismic operations, among others. The KMMN demonstrated the value of dedicated and citizen science data to enhance marine mammal conservation strategies to boost awareness and eco-tourism and to bring the public and science closer together, promoting research and effective conservation efforts.

Density dependence can obscure nonlethal effects of disturbance on life history of medium-sized cetaceans

Nonlethal disturbance of animals can cause behavioral and physiological changes that affect individual health status and vital rates, with potential consequences at the population level. Predicting these population effects remains a major challenge in ecology and conservation. Monitoring fitness-related traits may improve detection of upcoming population changes, but the extent to which individual traits are reliable indicators of disturbance exposure is not well understood, especially for populations regulated by density dependence. Here we study how density dependence affects a population’s response to disturbance and modifies the disturbance effects on individual health and vital rates. We extend an energy budget model for a medium-sized cetacean (the long-finned pilot whale Globicephala melas) to an individual-based population model in which whales feed on a self-replenishing prey base and disturbance leads to cessation of feeding. In this coupled predator-prey system, the whale population is regulated through prey depletion and the onset of yearly repeating disturbances on the whale population at carrying capacity decreased population density and increased prey availability due to reduced top-down control. In populations faced with multiple days of continuous disturbance each year, female whales that were lactating their first calf experienced increased mortality due to depletion of energy stores. However, increased prey availability led to compensatory effects and resulted in a subsequent improvement of mean female body condition, mean age at first reproduction and higher age-specific reproductive output. These results indicate that prey-mediated density dependence can mask negative effects of disturbance on fitness-related traits and vital rates, a result with implications for the monitoring and management of marine mammal populations.