Recent cetacean taxonomic changes and conservation action

Taxonomic uncertainty continues to be an impediment to efficientconservation, even for large and charismatic animals such as whalesand dolphins. This is exemplified by several discoveries in the last fewmonths alone: a new species of great whale was described in the Gulfof Mexico (Rosel et al., 2021); there was the discovery of a beakedwhale that is likely to be an undescribed species from the coastof Mexico (https://news.mongabay.com/2020/12/whale-of-a-find-scientists-spot-beaked-whale-believed-to-be-a-new-species); and,most recently, the South Asian river dolphin species (Platanistagangetica), was split into two separate and highly endangered species,the Indus and Ganges river dolphins (Platanista minor, and Platanistagangetica, respectively) (Braulik et al., 2021). These cases reveal notonly how much we still have to learn about whales and dolphins buthow difficult it is to gather enough information to able to understandand scientifically describe them, even for dolphin species found inrivers, with comparatively limited distributions, and living amongstmillions of humans. The river dolphin study, for example, took20 years to complete, years that also saw the ranges of both speciesdecline substantially.Although describing species is not equivalent to saving them,there is a link between increased taxonomic knowledge and increasedconservation attention (Morrison et al., 2009). Species form the basisfor almost all national and international wildlife legislation,environmental management, conservation planning, and allocation offunding (Mace, 2004). Effective conservation therefore depends onstrong and well-founded science based on taxonomy and systematics(Mace, 2004). It is important to recognize that although it isimperative that taxonomic decisions are based on sound science,these decisions also have far-reaching political consequences and asignificant impact on management and conservation on the ground.For example, a comprehensive review showed that the splitting ofspecies frequently results in increased protection (Morrisonet al., 2009).As two of the most endangered of all cetacean species, with eachnumbering only a few thousand individuals and listed as Endangeredon the International Union for Conservation of Nature (IUCN) RedList, the Indus and Ganges river dolphins are both in grave need ofincreased efforts to improve their habitat and reduce threats. IndusRiver dolphins have been increasing in abundance in recent years, butwith more than 80% of their habitat gone, the remaining distributionis vulnerable to climate change, coupled with increased demand forwater and rising levels of pollution (Braulik et al., 2015). By contrast,Ganges River dolphins, although more numerous and with a largerrange than the Indus river dolphins, are facing a formidable array ofthreats, in the form of large infrastructure projects that will modifytheir already depleted and degraded habitat into major dredgedshipping lanes (Kelkar, 2017). In the face of such overwhelmingtransformation, disturbance, and degradation of dolphin habitat, it isunlikely that any mitigation measures will be able to prevent acontinued or accelerating decline. These unique blind dolphins mayserve as sentinels, showing the value and importance of healthy,undisturbed, connected rivers, both for humans and wildlife, before itis too late