By Shanta Shamsunnahar
[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 Shamsunnahar is the Marine Protected Area Program Coordinator for WCS’s Bangladesh Program and a research participant in the survey.