[Note: This is the third blog in a series about the WCS-led marine megafauna survey, which is gathering data on whales, sea turtles, sharks, and other marine species inhabiting the coastal waters of Bangladesh. Data from the effort will identify biologically important locations for future consideration as marine protected areas.]
The WCS marine megafauna survey currently underway along the coast of Bangladesh involves two vessels. The larger vessel follows a transect line surveying for whales, dolphins, and porpoises (collectively known as cetaceans). Researchers on the smaller vessel focus on active fishing vessels by collecting data related to their catches and learning from fishers about the nature and scale of their fishing effort.
Recording various gear specifications contributes to our understanding of coastal artisanal fishing practices. Photo credit: WCS Bangladesh.
The team aboard the second, smaller survey boat, F. B. Jobeda, has the task of assessing the catches and bycatches of several different types of fishing gear operating in the coastal waters of Bangladesh. While the targeted finfish are of considerable interest, we are especially keen to investigate other species such as dolphins, porpoises, turtles, sharks and rays, as well as sea snakes—some of which are accidentally taken as bycatch.
On day two our team was preparing for the day’s work when we spotted a long liner—locally known as the Boiral—a fishing vessel that uses lines with thousands of baited hooks. By the time we reached the boat and established contact, the fishermen were already pulling in their lines.
A bigeye houndshark was identfied for the first time in our waters. Photo credit: WCS Bangladesh.
As a researcher, investigating this haul was fascinating, but on a personal level it was deeply disturbing. Among the 1150 hooks we examined there was a shark caught on almost every one. We managed to identify four different species, including an immature tiger shark.
The catch also included several individuals of a relatively small shark species that the local fishermen call “Gule Kamot” and which we didn’t immediately recognize. These beautiful fish have large sparkling eyes and a stout snout. Upon looking at them more, we identified them as big-eye hound sharks, a new species we had yet to record in Bangladesh.
The baited hook and line fisheries target large finfish but catch large numbers of sharks. Photo credit: WCS Bangladesh.
One of the females had 19 pups in her belly, and several others were clearly immature. We learned that these sharks have a very low market value and are used only as bait or simply discarded. Also, we discovered that some of the longliners are targeting endangered hammerhead sharks, due to their high market value.
This experience has strengthened my resolve to help find a balance between protecting of our country’s large and diverse marine megafauna and ensuring that fisheries are sustainable. Fortunately, WCS is partnering with the Government of Bangladesh to establish a network of marine protected areas that will promote sustainable fisheries while conserving threatened species such as hammerhead sharks.
This beautiful honeycomb whipray was caught in a drifting gillnet along the southern coast of Bangladesh. Photo credit: WCS Bangladesh.
The information collected by survey participants, as well as other data collected by a WCS-led citizen science network at fish landing sites throughout coastal Bangladesh, will also help inform future management actions and international shark and ray conservation efforts.
——————————————— Shanta Shamsunnaharis the Marine Protected Area Program Coordinator for WCS’s Bangladesh Program and a research participant in the survey.
[The is the fifth blog in a series about the WCS-led marine megafauna survey, which is gathering data on whales, sea turtles, sharks, and other marine species inhabiting the coastal waters of Bangladesh. Data from the effort will identify biologically important locations for future consideration as marine protected areas.]
As we sailed southeast from St. Martin’s Island towards deeper waters, we scanned the waters for marine mammals. Sighting conditions have been poor, and it has been five days since we last spotted a cetacean. At 08:30 we pass by several Sampans, small, elegant half-moon shaped fishing boats typical of the southeast coast of Bangladesh near the border with Myanmar.
One of the fishing boats encountered during the Bangladesh marine survey. Photo: WCS Bangladesh.
Then our team spots a large fish floating about fifty meters from the bow. We decide to take a closer look. To our surprise the belly-up fish is still very much alive when we pull it aboard and a couple of us get whacked by its powerful tail. The twelve-kilogram fish measuring almost a meter long is a giant Asian sea bass.
Just before noon the wind drops to nothing and the sighting conditions are perfect: Beaufort sea state zero, glare zero, fog zero. It was then we spotted four different species of sea snakes – Jerdon’s, black and yellow, spine-bellied and annulated sea. We also recorded a variety of seabirds, including: brown-headed, black-headed and Pallas’s gulls; common, whiskered, little, greater and lesser crested terns; a Eurasian curlew; and a couple of barn swallows circling our boat.
WCS Bangladesh staff scan the horizon for marine life from one of the survey boats. Photo: WCS Bangladesh.
But still no cetaceans. An hour later we encountered a cluster of sixteen drifting gillnetters targeting hilsa fish but that have high bycatch rates of marine megafauna—including dolphins, turtles, sharks and rays. We scramble to record data on the fishing vessels, which will help us understand the overlap of the distribution of marine megafauna and the fishing gears that entangle and kill them.
It was almost 4:00 in the afternoon when our survey leader Rubaiyat Mansur calls out “Sighting!” Shaken out of my afternoon fatigue, I see a blow and a body. It’s a Bryde’s whale, a marine mammal that can reach more than 16 meters in length.
During The expedition to survey marine megafauna, we identified several Bryde’s whales, which can reach more than 16 meters in length. Photo: WCS Bangladesh.
This was the first time in my life I had seen a whale. I was super excited and yelled out, “I am grateful to WCS for giving me this opportunity of a lifetime!” Our captain did an outstanding job at positioning the vessel as the whales circled around us. [Editor’s Note: Researchers from WCS-Bangladesh have previously published scientific research on Bryde’s whales in the Bay of Bengal].
After the thrilling encounter with one of Bangladesh’s marine giants, we arrive at our rendezvous spot to meet our smaller survey vessel F.B. Jobeda, the vessel in charge of investigating fisheries. There was a beautiful sunset but no sign of the boat. We tried to contact them by VHF radio but we received no answer. As the day turned into night we began to worry. Just as it started to get dark we made contact and radioed them our position so we could meet up to anchor for the night.
Survey staff record some of their findings during the expedition. Photo: WCS Bangladesh.
After eating dinner and entering the day’s data into our laptop computers we can finally relax. But as soon as we’ve turned in, a commotion on the deck wakes us. It turns out we have anchored too close to a fishing net which now threatens to entangle our boat. Fortunately our experienced captain, Kokhon Sarkar, and the crew get us out of the potentially hazardous situation. As if all this excitement wasn’t enough, the wind picks up, and we rock and roll through the night.
At 05:45, alarm clocks go off well before the sun rises. We could all use some more sleep. But another day of ocean adventures awaits. Despite the hardships, including no showers, smelly shipmates, and hours of searching for cetaceans in the hot sun or sometimes cold wind, I would not want to miss this amazing and truly life-changing experience.
——————————————— Nadim Parvesis a cetacean and fisheries observer for the survey.