Ocean Currents

Hector’s Dolphins Make Unlikely Comeback


All over the world, marine protected areas do exactly what they’re supposed to  – a superior job of keeping sea creatures safe from harm. Good news, but what’s particularly exciting is a new study showing that marine protected areas improve survival for marine mammals.

For 21 years, ecologists in New Zealand studied a marine protected area near Christchurch. The area provides shelter for one of the rarest dolphin species in the world, Hector’s dolphins. These small dolphins boast distinctive black-and-white markings and an unusually rounded dorsal fins. They’re also notable for a sadder reason – once hunted as “bait”, often tangled in gillnets, currently threatened by pollution, the Hector’s dolphin population has dwindled to a fraction of what it once was.

But like the nickname “hope spots” suggests, optimism for the species’ survival springs anew. The study results showed that since the marine protected area was designated, a significant shift has occurred: instead of continued decline, the Hector’s dolphin population has notably increased. Study author Dr. Liz Slooten noted, “This study provides the first empirical evidence that Marine Protected Areas are effective in protecting threatened marine mammals.”

This is a bright moment for dolphins, whales and pinnipeds everywhere. In California, for example, many of our new marine protected areas assure a place of refuge for not only fish, but for whales, dolphins, sea lions and seals. Some of the recently created ocean parks encompass feeding, resting and breeding grounds with the goal of reducing competition for food, disturbance (from noise and lights of fishing boats) and reducing entanglement risks in those key areas:

1. The Farallon Islands are most notorious for the great white sharks concentrated in nearby waters – but it’s the fact that the Farallons are home to the largest marine mammal colonies in the continental United States south of Alaska that brings the great whites to the area. Despite recognition from past presidents and the United Nations, only a small portion of the islands were actually protected.  Now, over 25 percent of the coastal waters off the Farallon Islands enjoy complete protection all year round.

2. A deepwater canyon within Monterey Bay provides a feeding ground for whales. Soquel Canyon has also historically served as place spot prawn trappers would drop their traps. This combination increased the risk of whales tangling in the trap lines – a risk diminished by the establishment of a marine protected area in the region.

3. South of San Francisco, Año Nuevo draws thousands of tourists keen to see the breeding elephant seals. About 2,000 pups are born in Año Nuevo each year – a vast improvement for a species hunted to near-extinction during the 1800s. To ensure their continued recovery, a marine protected area was sited near the elephant seals’ haulout location to reduce risk of entanglement and disturbance from fishing boats.


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