Prawn catch and mangroves link in Malaysia

The New Straits Times 11 Jan 09;

IN a paper presented at the National Fisheries Symposium in 2006, Universiti Malaya's Professor Dr Chong Ving Ching drew a link between mangrove loss and falling prawn catches.

Between 1980 and 2004, he noted that Malaysia lost about 23 per cent of its mangrove forest reserves

Then he compared it with landings of Penaeid prawns and Acetes shrimp over the last 30 years.

The analysis showed that the catches of both increased steadily during the early years and reached their potential yield by the late 1980s.

But after the 1990s, Penaeid prawn yields plunged to 65 per cent of its potential yield by 2003. Similarly, Acetes catches fell by 50 per cent.

There was little change in fishing effort at that time, he said.

The figure above illustrates this. The vertical bars at the bottom indicate trawl units while the numbers show the total number of licensed boats.

Chong has also been been monitoring nursery areas in the Matang mangrove forest, one of the major nursery areas for fish and prawns.

In less than a decade researchers had found that the biomass of fish in that area had decreased, Chong said.

'Trash', but it's also nice
The New Straits Times 11 Jan 09;

A FALLING catch doesn't necessarily spell the end of seafood dinners, just a different kind of menu that's not as appealing or star-studded.

The reason: more and more of the one million tonnes of seafood fishermen net every year is made up of trash fish rather than high value food fish.

High grade fish -- grade one and two -- comprise less than five per cent of total landings today, says Maritime Institute of Malaysia researcher Siti Nazatul Izura Ishak.

The causes are manifold and complex, she explains, ranging from environmental to enforcement. But of greatest concern, says her colleague Tan Kim Hooi, is mangrove loss.

Between the 1970s and 2005, the country lost about 20 per cent of its coastal mangroves.
Senangin, promfret, kurau and prawns depend on these coastal ecosystems.

While government policy discourages conversion of mangroves, the wetlands are still making way for aquaculture, housing and oil palm plantations, says Tan.

Coastal fishermen depend on the catch from Zone A and B that stretch up to 12 nautical miles from shore.

This is the area mangroves, coral reefs and seagrass beds thrive and where fish and prawns breed or seek refuge.

"If it's overexploited and degraded then there's little chance for marine life to replenish."

In a paper the duo presented at a marine fisheries and aquaculture management conference in August, they laid part of the blame on destructive fishing methods like modern trawlers, mechanised push nets and traditional bagnets or pompang.

Over the years foreign fishermen have grown bold and encroached into Malaysian waters, even into marine parks.

Local trawlers also encroached into traditional fishing zones and marine parks during the monsoon season.

Excessive coastal and island development have also worsened pollution.

Tan says components to better manage fisheries do exist but there are problems.

He cites the following example: "We have a zoning system but there are just too many fishermen in some zones, 70 per cent of coastal fishermen are in the 0- to 12-nautical mile zone."

Tan and Siti say solutions will have to tackle all, not just a few problems.

"We need practicable solutions that cover ecosystem protection, enforcement, pollution and illegal gear control. We must implement special species recovery plans and protect broodstocks," said Tan.

"Agencies, states and fishermen need to speak the same language and shoulder equal responsibility to make it work."