WASHINGTON (CN) - The National Oceanic and Atmospheric Administration's fisheries service has agreed with petitioners that the Taiwanese humpback dolphin may warrant federal protection, according to their 90-day finding. The news was enthusiastically received by the three conservation organizations that submitted the petition in March on behalf of the dolphins, whose population has declined to fewer than 80 animals.
In 2014, the agency had considered Endangered Species Act listing for these dolphins as the Eastern Taiwan Strait distinct population segment of the Indo-Pacific humpback dolphin, but ruled that they did not meet the criteria for listing as a distinct population segment.
The March 2016 petition, penned by the Center for Biological Diversity, the WildEarth Guardians and the Animal Welfare Institute, presented new taxonomic information indicating that the dolphins are actually a separate subspecies, not a distinct population segment. After reviewing the petition's sources, the agency agreed the dolphins merited another look. "The Endangered Species Act could help by providing technical expertise and resources to support Taiwan in conserving the rare dolphin," the groups noted in their response to the action.
"These small dolphins are perilously close to extinction," Dr. Naomi Rose, Animal Welfare Institute marine mammal scientist, said. "Once they disappear, they are gone forever. It's an encouraging sign that the U.S. has so quickly concluded that it could help by extending protections to this population."
Humpback dolphins have a wide raised hump on their backs, from which extends a dorsal fin that is comparatively small in relation to the fins of other dolphins. The Taiwanese dolphins have a less distinct hump, which slopes more gradually into the surface of the body, than other Indo-Pacific humpbacks, the action noted.
Based on information regarding geographical isolation, behavioral differences and a new study that demonstrates that the Taiwanese dolphins have significant pigmentation differences from the closely-related river delta dolphins (Sousa chinensis chinensis) in mainland China, the Taxonomy Committee of the Society for Marine Mammalogy has officially revised the taxonomy to list the Taiwan dolphins as a distinct subspecies (S. chinensis taiwanensis), the action said. "The Taiwanese dolphins were clearly diagnosable from those of mainland China under the most commonly accepted 75 percent rule for subspecies delimitation, with 94 percent of one group being separable from 99 percent of the other." Both subspecies begin life as grey animals, and shade to pink as they age, some with grey spots.
The dolphins' small population size and long age-to-maturity (12 to 14 years) combines with threats from fishery by-catch, pollution, coastal development and degraded habitat to worsen the outlook for these shallow-water coastal-hugging dolphins. With only an estimated 45 mature animals remaining "loss of only a single individual within the population per year would substantially reduce population growth rate," the agency said.
"The Taiwanese humpback dolphin is listed as 'critically endangered' by the International Union for Conservation of Nature (IUCN), an international authority on the conservation status of species," the group's petition stated. That is the highest level of extinction risk under the IUCN ranking system.
The 90-day petition finding is the first step in the long process to secure ESA listing status. The agency, having reviewed the petition's information and sources, as well as other information in the agency's files, now initiates a status review that is to be completed within 12 months of receipt of the petition. If the status review finds that the listing is warranted, the agency will initiate a proposal, to be finalized within 12 months. To that end, the agency requests comments, scientific information and peer reviews of the data at each stage.
"It's great that these rare dolphins are a step closer to endangered species protection. Small cetaceans around the world are disappearing, the baiji in China went extinct, and the vaquita in Mexico and Taiwan's humpback dolphin are nearing extinction, and we need bold action to save them," Miyoko Sakashita, oceans director at the Center for Biological Diversity, said.
Comments and information on the petition finding are due July 11.