Adventures Off the Tanzanian Coast: Unexpected Blasts Accent a Pew Marine Fellow’s Work

  • by Deborah Horan
  • February 04, 2016
  • Dispatch

Plying distant waters, Pew Marine Fellow Gill Braulik is filling the vast gaps in scientific knowledge about marine mammal habits off East Africa.

Pew marine fellow Gill Braulik explores waters around the world, including here on Pakistan's Indus River, studying dolphins and other marine mammals. (Albert Reichert)

Gill Braulik was standing starboard side, binoculars in hand, when she saw the distinctive plume of water shoot into the air. The marine biologist was too far away to hear any sound, but she knew immediately that the spray wasn’t from the whales her research team had been tracking in an ambitious effort to map ocean mammals off the coast of Tanzania.

It was something more sinister.

“I just saw a dynamite blast,” Braulik shouted to her colleagues over the din of the motor of their 50-foot catamaran, the Walkabout. “Let’s write down the time.”

At that exact time—11:32 a.m. on a March day in 2015—a short, sharp ping was recorded by the boat’s hydrophones, which had been installed to help the team locate the muffled tones of whales and dolphins. Fishermen use dynamite because it kills many fish at a time and makes it easy to collect them. But it also frequently destroys coral reefs and other habitat fish need.

Braulik and her colleagues soon realized that they had witnessed an incident of illegal dynamite fishing—and it wasn’t the only one. Over the next 31 days, the shipboard recordings documented 318 bombings along Tanzania’s shores, including two days with more than nine blasts per hour. The majority—almost 62 percent—occurred in waters less than 50 miles from Dar es Salaam, capital of the East African nation.

“We didn’t even set out to collect data on blasts,” Braulik says. Instead, the team of six Tanzanian and international marine biologists, a Spanish captain, and two crew members had planned to spend six weeks at sea last March and April assessing the marine mammals inhabiting the Indian Ocean coastal waters for a project supported by The Pew Charitable Trusts and the Wildlife Conservation Society. 

“Now we’ve got this really interesting side line,” she says. “We’re hoping the information we’ve collected will help Tanzanian authorities put an end to this kind of destructive fishing.”

Braulik and other researchers quickly published the unexpected data in a November report issued by the Wildlife Conservation Society that catalogued the evidence of bomb blast fishing during the voyage.

“Documenting this is important,” says Andrew Read, a marine biologist at Duke University who is familiar with Braulik’s work. He is also impressed by Braulik’s broader quest to record the habitats of mammals in waters where few biologists have gone before. “I admire what she’s doing,” Read says.

Originally from London, Braulik has spent more than 15 years studying marine mammals in places such as Hong Kong and Pakistan. At times it has been rough, even dangerous. In 2001, she and her crew came under gunfire while traveling on the Indus River in a remote tribal area of Pakistan and escaped unharmed only after their police escorts negotiated safe passage with the attackers. She has spent the past 2½ years living in Zanzibar with her two children, who are 3 and 7.

Plying distant waters, Pew Marine Fellow Gill Braulik is filling the vast gaps in scientific knowledge about marine mammal habits off East Africa.

In 2013, Braulik won a Pew marine fellowship to map marine mammal habitat along Tanzania’s coastline and create a model for collecting this type of data that can be easily replicated in other countries. She will complete the fellowship this year and hopes next to map the habitats of whales and dolphins in Mozambique.  The work is important to help determine which species live where and whether any of the animals face extinction—essential information that East African governments currently lack.

The work can be tedious. On the six-week Tanzanian voyage, Braulik and her colleagues served as lookouts for up to 12 hours each day. They slept in the boat’s four cabins and subsisted on rice and beans, ugali—a Tanzanian maize porridge—and the fish they caught. For the most part, it was smooth sailing, interrupted by only one tropical storm that poured unseasonable rains onto the boat for five days.

Every so often, the calm would be punctuated by an animal sighting, which electrified the crew. On one occasion, they watched hundreds of spinner dolphins swim and splash and flip out of the water, a pod so large it stretched all the way to the horizon. Sometimes the playful dolphins would swim along the boat’s bow, gliding along the waves like surfers.

“It’s pretty grueling with the heat and the motion of the sea,” Braulik says. “So when somebody spots something, there’s real elation. Every time, it was really exciting. We had really good luck and a lot of fantastic sightings of many species.

“The most amazing days were in the Pemba channel, between the Tanzanian mainland and Pemba Island,” Braulik continues. “We encountered so many different species there, one after another. It’s a special place.”

One rare encounter began when Braulik saw a big swirl of water appear alongside the boat. Just below the surface was a dugong, a mammal related to the manatee that looks like a cross between a walrus and a hippo. The unusual animal is on the Red List of Threatened Species compiled by the International Union for Conservation of Nature and is listed as extinct in many waters. On another occasion, the team spotted a humpback dolphin, which is also on the IUCN Red List.  In all, Braulik and the team catalogued 10 species of dolphins and whales, plus the dugong. But the sightings also gave the team a glimpse of the hazards that marine mammals face in the area: 15 of 36 endangered humpback dolphins that the team saw had scars from fishing nets on their dorsal fins, recognizable by the unusual straight lines found at regular intervals, similar to the lines of a net.

In December, the team finished mapping the places where they saw the animals, information that will help to fill gaps in scientists’ knowledge about where various species live and which ones might be endangered. These baseline data will guide Tanzanian officials as they create marine reserves and designate fishing areas in order to reduce the number of dolphins and whales that die after becoming entangled in fishing nets.

Braulik also hopes that the separate blast data—which will be provided to Tanzanian officials along with the audio recordings of the dynamite fishing—will prompt the government to take stronger measures to prevent fishermen from throwing bombs that kill scores of fish and damage coral.

“I’m quite happy and excited about our findings,” Braulik says. “I think it’s been very successful, and I hope that it will serve as a guideline for where we should be focusing our efforts on conservation.”