Wednesday, May 21, 2008

Following FADS is risky and can be fatal

Going with the crowd can be risky for juveniles, especially when it involves a FAD. It can lead to death by capture in a purse seine net, or perhaps to an ecological trap that can harm the group.

Fish Aggregating Devices (FADs) are floating objects that attract large and small tuna. Fishermen rely on this poorly-understood aggregating behavior of tuna and use FADs to exploit populations that might otherwise be hard to catch.

The result is enhanced fishing succes, and perhaps even worse is the apparent risk of enticing tuna to move away from ecologically favorable areas to places where it's harder to survive and thrive.

Your mama always told you to stay away from FADs, and now we know she was right...if you're a young tuna.

8 comments:

Jives said...

And here I thought this post was going to be about parachute pants.

Edible SF said...

you're gonna have to explain exactly what that is floating there in the ocean?

Mark Powell said...

It's a fish aggregating device (FAD). They need not be fancy, just something floating on the ocean, and they can still work when they're fairly small.

This bamboo raft is the float for a "bayao," which translates as "resting place." Like other “fish aggregating devices” or FADs used around the world, this bayao was placed in the open ocean to attract fish, such as migrating tuna, that use it for shelter and then can be caught in nets. The raft is tied to a long nylon rope weighted to the ocean floor with a cement block. About 30 feet down, coconut leaves woven together stream out from the anchor line, 10 feet in all directions, forming a mat under which fish such as migrating tuna hide. Image courtesy of 2007: Exploring the Inner Space of the Celebes Sea.

For more info, see: http://oceanexplorer.noaa.gov/%E2%80%8Cexplorations/07philippines/logs/oct4/media/fado_600.html

Rick MacPherson said...

i wish i had a picture to post, but the fads we installed in one of our mpa's in papua new guinea are as rustic as the one in your image, mark... but damn, do they work well!

we installed some surface and some subsurface fads made from local bamboo and palm fronds... it was an inspiring local community-based conservation project that brought many villages together...

in the near-shore fads, we are working to attract bream and sweetlips and other locally sourced species in an effort to replace natural spawning aggregation sites that were destroyed...

one of the practical conservation challenges of course is that fad sites make for prime poaching sites...

how have you addressed this challenge in your experience?

Mark Powell said...

Thanks Rick. I haven't built FADs, so I can't answer your question. Mostly I worry about them in open ocean fisheries, where they create risks of overfishing and excessive bycatch of juvenile fish in purse seine fisheries. It's interesting to hear about their conservation benefits in attracting people away from spawning aggregation sites.

Tim Adams said...

There's quite a bit of confusion about different kinds of FADs. We're planning to produce a short information document soon to explain the different implications of FADs in industrial offshore fisheries and in artisanal inshore fisheries.

Tim Adams said...

@Rick MacPherson - on how do you handle the challenge of poaching around FADs?

Most inshore FADs that are deployed in the Pacific are public FADs deployed by government, so poaching is not an issue.

In some places, FADs may be in demarcated fishing rights areas or MPAs where only certain people are allowed, so poaching is treated the same way as any other encroachment.

By the way, ANY mechanism that increases the number of fish in one area much more than other areas is going to be an inducement for people to fish there, and compliance/enforcement has to be taken into account from the start.

One way around poaching on "private" FADs is to keep them entirely subsurface. It requires careful design and deployment, but if the FAD float is not visible then the only people who can find it are those who know the exact position.

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