Pioneers for sustainable trawling (Image: Jeff Hunter/Getty)

Gallery: Life thriving after trawling in an ocean desert

THE sky is still black when Tim Maricich eases the Donna Kathleen out of Morro Bay, a fishing town in south-central California. The vessel yaws in the waves, a child’s toy in the expansive Pacific Ocean. Wobbly with seasickness, I stumble to the railing and puke.

An hour later, Maricich kills the engine and several deckhands manoeuvre a remotely operated vehicle, the Beagle, overboard. It floats briefly, a hulking yellow box, before sinking out of sight. For the rest of the day – all 10-plus hours of it – it will serve as our eyes, relaying images and video of the sea floor below.


I am travelling with an unusual crew: conservation biologists who have been trawl fishing. Bottom trawling – in which large nets are dragged along the sea floor – is often demonised as the most destructive method of fishing. Its catch is indiscriminate, and net frames weighing several tons can tear apart sea-floor habitats like reefs and seagrass nurseries. The industry is frequently compared to clear-cutting forests.

Two weeks earlier, a fishing boat had repeatedly trawled the stretch of muddy floor beneath our ship. “He mowed the lawn five times,” says Mary Gleason, a biologist with The Nature Conservancy, an international conservation organisation. Gleason isn’t upset, however: the trawl was the conservancy’s idea. The impact of trawling on muddy sea floors is poorly understood, and Gleason and her colleagues hope to change that.

Controlled trawl studies like this one are rare as few researchers can dictate when fleets go out and where they go. But the conservancy is in a unique position. Following the collapse of the Pacific Coast bottom fish fishery in 2000, it bought permits from struggling fishers. It now owns 7 per cent of the catch quota for Pacific Coast bottom fish, and has a monopoly over waters extending out from Morro Bay. This has allowed it to launch an ambitious plan: to create a new sustainable fisheries model.

To start with, the conservancy worked with fishing fleets to map out 1.5 million hectares of no-trawl zones, which the Pacific Fishery Management Council, the federal agency that oversees all fisheries along the US’s west coast, adopted. It then launched a series of experiments to find out how to fish more responsibly.

One approach involved leasing permits for long-line fishing to former trawl fishers. The day after my ordeal at sea, I met with Bill Blue. Blue was a reluctant recruit to the long-line project, but he recognised that the fish were running out and something had to change. Three years on, and he is finally starting to make a profit. The conservancy’s long-line fishers have discovered a niche market for live fish. A dead trawl-caught fish such as black cod sells for $0.4 per kilogram, while the live ones sell for $2.7 a kilo.

But trawling is still necessary, says Blue. Flatfish live near the sea floor, beyond the reach of dangling hooks. So in 2008, the conservancy launched a five-year trawl study. “Our goal was not to ban trawling but to diversify the fishery,” Gleason says.

Gleason and colleagues identified a strip along the continental shelf 14 kilometres from Morro Bay that had not been trawled for at least a decade. They then marked out eight plots, each measuring 1 kilometre by 330 metres. Four would remain pristine, the other four would be trawled.

The team wanted to know how often trawlers can rake over a section of muddy sea floor before habitats can no longer recover. Records held by the National Marine Fisheries Service show parts of the continental shelf can be trawled between zero and 10 times a year. So last year, to mimic low-intensity trawling, four plots were hit twice. This October, they were each trawled five times, mimicking a high-intensity trawl. The Beagle took pictures immediately after each event, as well as six and 12 months after the first trawl.

Early signs indicate that marine life survived, even thrived, after last year’s trawls. Since then, the Beagle has spotted sharks, flatfish and thick schools of squid that dove, kamikaze-style, into its red laser lights. Donna Kline, a fish ecologist at California State University in Monterey Bay, thinks that far from destroying a habitat, the trawl may have created a new one by etching grooves into the flat bottom.

Sharks, flatfish and schools of squid have been spotted near the trawled sea bed

It is too soon to know the impact of the more intensive trawl: the team observed it for the first time during my visit, two weeks after the trawl. Back in Morro Bay, Kline scrolls through the day’s pictures on her computer. Notable among them is a shot of brittle stars webbed across the sea floor. Could intensive trawling have benefitted some species? The effect appears to be positive, at least short term, says Kline. But, she cautions, “we don’t know if that effect is going to hold up”.

When the article was first posted, the distance of the study site from Morro Bay was incorrectly given.