by Samuel Turvey
Oxford University Press (198 Madison Ave., New York, NY 10016), 2008. 224 pages, paperback. $29.95.
Reviewed by Merritt Clifton
Samuel Turvey, born in Lohja, Finland, as a child enjoyed a rare sighting of the Lake Saimaa seal.
Landlocked by receding glaciers about 9,500 years ago, the Saimaa seal has adapted to living in fresh water. At the time, researchers believed there were barely 100 Saimaa seals left. The most recent count is about 320.
“Getting entangled in fishing nets is the biggest single cause of death. If we get rid of that, the Saimaa seal could probably survive global warming,” World Wildlife Fund representative Jari Luukkonen recently told Terhi Kinnunen of Agence France-Press.
The same is also now true of river dolphins and porpoises worldwide, including the highly endangered vaquita whale of the northern Gulf of California. More than just entanglement, however, contributed to the loss of the baiji, the Yangtse river dolphin, last known to exist when the last captive baiji died in 2002.
Turvey grew up to earn a Ph.D. in Chinese paleontology, but inspired by his Saimaa seal encounter, felt impelled to try to discover the fate of the baiji.
Turvey’s title, How We Failed to Save the Yangtse River Dolphin, is a bit of a misnomer, since his involvement began after the fact. Mentioned in ancient times, but apparently never as abundant as the now scarce Yangtse River porpoise, the baiji was probably already headed toward extinction when 17-year-old American duck hunter Charles Hoy shot the first scientifically described specimen in 1914.
Baiji were at times hunted for food and oil, especially during the so-called Great Leap Forward under Mao tse Tung, when as many as 30 million Chinese people starved to death, but mostly they appear to have been accidental victims of “rolling hook” fishing, fish netting, and boat traffic along the river, which has long been among China s busiest thoroughfares.
Not more than 200 baiji were left by the time field studies started circa 1979. Inept attempts to catch baiji for captive breeding, lack of knowledge about the needs of baiji once captured, institutional rivalries, and the perception of international conservation organizations that the baiji was a lost cause all contributed to the failure of last-ditch efforts to resuscitate the species.
Turvey appears to be especially bitter about the lack of grant funding allocated to saving the baiji, seemingly oblivious to the need for someone to raise the funds to be granted. If major funders would not try, baiji enthusiasts might have taken their case directly to the public via direct mail and e-mail.
As Turvey notes, renowned marine mammalogist Stephen Leatherwood became involved toward the end of his life, and knew how to do what needed to be done, but he died in January 1997. That probably doomed the whole cause.
Turvey’s role was to organize and lead a two-boat survey of the entire length of the Yangtse and major tributaries in 2005 that found not a trace of a living baiji and no credible reports of recent sightings. A blurred and distant video of a purported sighting in a tributary turned up in 2006, and another unconfirmed sighting was reported in October 2016, but even if one or two baiji remain, chances are slim that they will be enough to rebuild the population.
Turvey recounts the loss of the baiji in hopes that lessons can be learned on behalf of other rare species, including the vaquita, of which barely three dozen remain. There were 567 vaquitas in 2007. Entanglement in gill nets reportedly accounts for 80% of the decline.
Late concern for declining populations
Other Asian river dolphins have reached the scarcity that the baiji reached before anyone sounded an alarm.
The Wildlife Conservation Society and Bangladesh Cetacean Diversity Project told Shafiq Alam of Agence France-Presse in October 2008 that they have counted an unexpectedly large population of 5,832 Irrawaddy dolphins in the estuaries of coastal Bangladesh.
But that was almost the only unequivocal recent good news in recent decades about Irrawaddy dolphins in any of their five Southeast Asian habitats. They have already been declared “functionally extinct” in Laos.
Poultry farming not a solution
As of July 2008, about 100 Mekong Irrawaddy dolphins remained in Cambodia, Sun Mao of the Cambodian Rural Development Team told Guy Delauney of BBC News. A ban on the use of gill nets cut down the number of dolphins accidentally caught, Delauney reported. Instead, CRDT has helped locals to reduce their reliance on fishing by offering alternatives such as poultry farming.
Even from a perspective limited to species conservation, increased poultry farming in estuarial dolphin habitat would be alarming. Poultry excretia, rich in phosphorus, is implicated in declining water quality in U.S. inland waters from the Arkansas River to Chesapeake Bay. River dolphins would be affected if the U.S. had any.
Not surprisingly, the Mekong Irrawaddy dolphin population in Cambodia is now down to an estimated 78-91 individuals.
Thirty years after Pakistan prohibited hunting the Indus river dolphin, which is blind and lacks a dorsal fin, this species had increased to 1,330, according to a spring 2006 survey. The Indus river dolphin appeared to be a short-term beneficiary of a 25% increase in glacial melt from the Himalayas, attributed to global warming. As the glaciers recede, this stimulus will decline––and as of 2015, the Indus river dolphin population was reportedly down to 1,100-1,200.
The dolphin population of the Upper Ganga river in India increased from 20 in 1993 to 52 as of 2015, according to World Wildlife Fund data. Accomplishing this required building a sewage treatment plant, stopping fishing and mining along 165 kilometres of river, and persuading farmers to fertilize only with cow manure.
Pink river dolphins
Supot Chandhrapornsil of the Thailand Department of Marine and Coastal Resources warned in May 2008 that only about 40 Indo-Pacific humpback dolphins remain in Khanom Bay at Nakhon Si Thammarat. Four of the pink dolphins were killed by entanglement in fishing nets during the first five months of 2008.
The current status of that population is unknown. Meanwhile, the Indo-Pacific humpback dolphin population in Hong Kong waters fell from 158 in 2003 to 78 in 2011, according to the Hong Kong Dolphin Conservation Society.