Threats to Sea Turtles

 Threats to Sea Turtles in Bangladesh

Sea turtles, despite their ancient and majestic existence, face a multitude of threats in the coastal regions of Bangladesh. These threats have been observed during the course of our project, and they require urgent attention and action. Currently emerging threats are arising from the habitat alteration, lighting disturbance along the northern zone of Cox Bazar-Teknaf peninsular beach. There were some record of very severe egg poaching occurrence by brutally killing mother turtle. It suspected that the case was happening for long although limited scale. 

In last 17 seasons (2005-19) the organization released over 600 thousand olive ridley and green turtle hatchings in the wild through SRCWP project. This population hopefully maintaining the ecological balance in the BoB marine ecosystem. The offshore fishing community is being continuously motivated and trained and bycatch releasing is now common as fisher’s are cooperating and respecting and participate the conservation. But this good work only applied to gill nets but while north to western Bay of Bengal is full of deadly Marine set Bag net (MSBN) locally called Behundi jal. These are funnel type structure and set as water flows during low tide or high tide. Turtle and small cetaceans can’t escape against strong current inside MSBN. Those are installed for long time and fishermen harvest only after high or low tide when water becomes steady. And turtle are not able to withstand such 5-6 hours without breathing. Estimated there are fifty thousand MSBN in the fishing fleets in our marine territory. 

The mechanized shrimp net trawler is another main threat to marine resources. During the last 5-6 years, such trawlers illegally come 2-3 km from the coast where water is below 20 meters deep, while by law, these should not come where water is shallower than 40 meters. But there is no monitoring, and the fisheries department should take immediate action. Such trawl nets drag near or on the bottom and destroy the fisheries' resources too. Turtles and small cetaceans, once they get inside, can’t escape. The same thing happens with MSBN; everything in the sea, like invertebrates and small fish fry, all get in and never come out and die without any benefit for the fishermen. Due to this destructive fishing activity, fisheries resources have declined in the Bay of Bengal Bangladesh region. The trawl nets are not using TED (turtle excluder Device) which helps turtle and cetaceans to escape and help balance the ocean environment. Researchers of Marinelife Alliance urge the government and respective Fisheries Departments to take necessary measures to overcome disaster and save our marine resources. Bycatch mainly happens by large mechanized shrimp trawl nets (MSTN) and nautical set bag nets. (MSBN). Both net is similar in design. 

Usually, MSTN is supposed to use TED as government regulation imposed after a long time (10 years) imposition of the embargo by the US government from shrimp import from countries whose fisheries do not use TED in shrimp industrial trawling nets. In our data during 2014-2015 in the marine area, we observed several travel nets did not use TED. We did some awareness programs, but fishermen said turtles died before we could release them during harvesting. Trawlers also come very close to shore, shallower than 40 meters, like 15-20 meters, which is illegal.

MSBN is very destructive. The government should ban these gear from the country's marine fisheries. These are similar shape gears but smaller than a trawl net, fixed in a place. Work with tide, they remain long, and turtles, small dolphins, and porpoises can not escape for life. These gears stay for 4-6 hours, and turtles or dolphins die far before the harvesting time. Almost 50,000 MSBN gears are in fishing operations in Bangladesh marine waters.

BYCATCH

• TED is still not used by the industrial shrimp trawls net; collaboration is necessary by the international shrimp importers on the imposition of TED use by the shrimpers.
• The more significant numbers of artisanal fisheries are by MSBN; the same funnel-type net is used in this fishing and is responsible for many bycatch other than trawl net.
• Nearshore fishing by gill nets and MSBN is creating death traps for the emerging nesting turtles, and addressing these issues is very urgent.
• Large mechanized shrimp trawlers have been fishing close to shore within 1-2 km in recent years illegally, but they are not supposed to come below 40-meter depth according to fisheries law. 

Large mechanized shrimp trawlers are fishing close to the shore, which is illegal and detrimental to marine life. The lack of Turtle Excluder Devices (TEDs) in some trawl nets exacerbates bycatch problems.

Marine Set Bag Nets (MSBN): MSBN, locally known as "Behundi jal," have become a significant threat. These funnel-shaped nets are placed for several hours, trapping turtles and small cetaceans that cannot escape strong currents inside them. An estimated 50,000 MSBNs operate in Bangladesh's marine waters.

Illegal Fishing Practices: Mechanized shrimp trawlers, which should not operate in waters shallower than 40 meters, are doing so illegally, destroying marine resources and capturing sea turtles.

Habitat Alteration and Lighting Disturbance: One of the emerging threats to sea turtles in Bangladesh is the alteration of their nesting habitats. Coastal development projects, such as the coal-based power generation project at Matarbari and the marine drive development along the Cox's Bazar coast, have led to erosion, habitat destruction, and the vulnerability of nesting sites. Artificial lighting from hotels, campfires, and other tourist activities disrupt nesting turtles, particularly on St. Martin Island and the Teknaf Peninsula.

Egg Poaching: Egg poaching remains a significant problem along the coast. This illegal activity is incredibly intense in the eastern village of Sonadia Island. Efforts to combat egg poaching are still relatively new in the Teknaf Peninsula, necessitating motivation, law enforcement, and community involvement to mitigate the issue. Some egg collectors attempt to trade these stolen eggs in nearby towns.

Indiscriminate Development/Erosion/Habitat Alteration: The development of marine drive projects, including the extensive use of concrete blocks and sand-filled geo-textile bags to prevent erosion, has ultimately altered sandy beaches, contributing to the loss of nesting habitat.

Artificial Lighting, Tourism, Disturbance, and Human Intervention: Tourism-related activities, such as excessive lighting, campfires, and night-time disturbances, have become a significant hindrance to nesting sea turtles. These issues are increasing in Teknaf Peninsula, Sonadia, and St. Martin Island. Floodlights at Laboni Beach and beach seine fishing along the peninsula and Sonadia during high tide exacerbate the disturbance to nesting turtles.

Predation

Predation poses a significant challenge along the coast, impacting both sea turtle nests and adult turtles. Addressing this issue requires effective population control measures. One essential approach is initiating a birth control program for small predator populations.

Dog Predation: Dogs have been identified as a major predator of sea turtle nests and adult turtles along the coast. To mitigate their impact, population control measures for dogs are necessary.

Jackal Predation: Jackals are another source of nest predation, although their threat is not as intense as that of dogs. Jackal predation can be controlled with the assistance of night observers. Jackal invasions on Sonadia Island have become more prevalent since the 2012 season. Local islanders attribute this increase to the dense Casuarina plantation, which provides a suitable shelter for predators during the night.

Water Monitor Lizard (Varanus salvator): These lizards are natural predators and have been recorded at St. Martin Island. However, their presence and intensity have decreased, likely due to the destruction of their habitat caused by tourism expansion. Given their endangered status in our country, in situ protection and management actions are necessary.

House Crow Predation: House crows at St. Martin Island, and to some extent at Sonadia Island, have been documented preying on sea turtle hatchlings during the daytime, mainly if left unattended. The influx of these crows from Teknaf town, coinciding with the growth of tourism and hotel operations on St. Martin Island over the past 15 years, has contributed to the predatory impact. Moreover, these crows have been harming the local resident bird population by preying on their eggs during the breeding season.

Hog Badger Predation (Arctonyx collaris): Predatory behavior by hog badgers has been recorded at various spots along the Teknaf Peninsula beach, including Pechardwip, Cepotkhali, and Shilkhali. They primarily target nests or eggs, especially when left unattended. Mitigating their impact requires careful attention to these vulnerable sites.

These threats are detrimental to the sea turtle populations in Bangladesh and require immediate attention from the government, fisheries department, and conservation organizations. Collaborative efforts are essential to mitigate these challenges and protect the delicate balance of marine ecosystems in the Bay of Bengal.