Catastrophic Decline of Atlantic Humpback Dolphin
Atlantic humpback dolphins are now on the brink of great peril, according to WCS (Wildlife Conservation Society) and the IUCN’s (International Union for Conservation of Nature) Cetacean Specialist Group.
The shy dolphins have faced a dramatic decline due to prevalent human activities in coastal waters, and threats include entanglement in fishing gear, offshore construction such as port development, and hunting for human consumption.
Now, the mammals are considered by the group of scientists to be among the continent’s most endangered mammals.
This latest assessment was confirmed by Tim Collins, of WCS’s Ocean Giants Program and the Africa Coordinator of the IUCN’s Cetacean Specialist Group.
Collins said, “Our recent assessment suggests that the global population of the Atlantic humpback dolphin likely numbers fewer than 1,500 breeding adults distributed among several isolated sub-populations, most of which appear to be very small.”
Growing up to 2.5 meters (more than 8 feet) in length, the Atlantic humpback dolphin is gray in color and has a characteristic hump just below its dorsal fin. These dolphins are shy, occur in small groups, and rarely venture more than a few kilometers from shore.
From “Vulnerable” to “Critically Endangered” Mammals
The gray Atlantic humpback dolphins have been uplisted from “Vulnerable” to “Critically Endangered” on IUCN’s Red List of Threatened Species.
The previous “Vulnerable” listing for the species was based largely on the assumptions that dolphins were more abundant in areas where the species was known to occur. Aside from that, there were presumptions of occurrence in many areas in the absence of a survey.
For the new Red List assessment, researchers conducted a thorough review of the available data. They found that the dolphins occur in very low and apparently declining numbers throughout most or all of their range. Most populations are extremely small and several appear to be isolated.
Probable Causes of Decline
The group of scientists outlined several causes of the sudden decline of the population of the African dolphins.
One is a bycatch in fisheries, which is considered major cause of the declines. This assessment was identified or suspected everywhere the species has been studied.
Hunting is the other reason which is common in several areas. Aside from that, threat of coastal development in remaining habitats is increasingly prevalent.
Finally, adequate management interventions that limit habitat loss, bycatch and hunting are sorely lacking as well.
What Needs to Be Done
In the absence of targeted and sustained conservation management efforts, the researchers conclude that the species will continue to decline. These measure are crucial to save the mammals on the brink of extinction. That is why the researchers highlighted the need for a protected area network to address this problem.
Researchers have cited that several marine protected areas provide for Atlantic humpback dolphins. One example is the recent creation of a marine protected area network in Gabon.
In addition, the group of scientists stressed the need for greater attention to counter the continuing decline of the West African dolphin.
Howard Rosenbaum, Director of WCS’s Ocean Giants Program and a member of the IUCN Species Survival Commission’s Cetacean Specialist Group, said: “The new Critically Endangered listing will hopefully provide greater attention and resources to mitigate primary and cumulative threats faced by the Atlantic humpback dolphin, as well as proactive strategies for protecting the species and its vital habitats in key parts of the range.”
