The Gulf of Mannar's trawling problem

By Tanvi Vaidyanathan

As a young marine scientist who grew up in southern India, I have long been captivated by the Gulf of Mannar, and I am hardly the only person. With its iconic seahorses, charismatic sea cows and thousands of other marine species, the area is known for its incredible biodiversity. Located between the southeastern tip of India and the northwestern tip of Sri Lanka, it is home to mangrove and sea grass habitats- ideal feeding and breeding grounds for many species.

Unfortunately, the Gulf of Mannar is also known for its longstanding problems with overfishing and destructive fishing practices. Since the introduction of trawling in the 1960s, the area has come under incredible pressure from commercial fisheries and small scale fishers alike. The widespread use of push-trawls (‘thallu madi’) — adopted by artisanal fishers keen to keep up with the commercial fisheries — has been particularly disastrous. A modified gill-net that targets shrimp, the thallu madi also catch juvenile fishes, cephalopods and other animals. This gear is often operated over shallow sea grass habitats, bringing up a fair number of syngnathids (seahorses and pipefishes) as bycatch.

Over the past few decades, a number of conservation measures have been introduced in the Gulf of Mannar, including a “Marine National Park” designation by the Indian government in 1986, a UNESCO biosphere park designation in 1989 and a ban on seahorse fishing in 2001. But, it is not clear if they have made a difference.

Fishing boats on the Gulf of Mannar. Photo via Marcus334/Wikimedia Commons 

Fishing boats on the Gulf of Mannar. Photo via Marcus334/Wikimedia Commons 

Take seahorses as an example. In the five years leading up the fishing ban, exports were estimated to be around 3.6 tons per year. In 2001-02, the year following the ban and when the next estimates were carried out, exports actually increased to somewhere between 4.35-9.75 tons, potentially due to growing demands for seahorses from other Asian countries. In the nearly 15 years since then, the enforcement has been spotty at best. Illegal trade happens to be a major issue, though the true extent of it is not known. What we do know is that the region is home to around 150,000 people, over 70% who still depend on fishing for their survival. Over 1200 mechanized and 1100 non-mechanized fishing vessels enter the Gulf of Mannar on a regular basis.

We also know that demand for seahorses still exists. In India, the trade feeds the global traditional Chinese medicine industry. Seahorses have also emerged as an alternative to the declining sea cucumber trade, the majority of Indian seahorses exported to other countries are sourced from the southeastern coast, mostly from the Gulf of Mannar and the nearby palk bay. While a small portion of the seahorses come from a targeted fishery, most were landed as incidental catch (bycatch) from trawls operating in the gulf. Prior to the ban, seahorses were thought to represent 60 to 70 percent of the fisher’s income in some areas.

What impact have the Indian government’s conservation measures had on seahorses and other marine fishes? Likewise on the livelihoods of fishers and fishing communities in the Gulf of Mannar? In this context, how does one balance the need for conservation with the need for food security?

These are some of the questions I intend to answer as part of my PhD work with Project Seahorse. As I embark on eight months of intensive field research in the Gulf of Mannar and beyond, I will be posting my findings in this space. Stay tuned!

Tanvi Vaidyanathan is a PhD student with Project Seahorse. Follow her on Twitter @TanviVaidyanath.