Wednesday, May 09, 2007

Why we need ocean refuges in California

Blogfish listens, and a sincere commenter asks why MPAs (ocean refuges) in California? Big question, here's a short version of the answer.

Most of California's natural reefs have very few big fish. According to Milton Love and his colleagues: "High fishing pressure on most rocky outcrops in central and southern California has led to many habitats almost devoid of large fishes." This is a problem that needs a solution. Big rockfish are important for reproduction, and the term BOFFFs was invented to describe the special value of big old fat female (rock)fish.

What to do? These habitats are dominated by Sebastes rockfish, which are generally slow-growing, long-lived fish that congregate near rocky reefs. It is much more efficient to protect these fish by closing some areas to fishing. As a more difficult alternative, overall fishing rates would have to be drastically reduced if lower catch limits alone were used to allow some of these fish to escape capture year after year and grow big.

It's true that the biggest problems in California are offshore in deeper water, but some nearshore fish are also experiencing heavy fishing pressure and localized depletion if not overall depletion. With fishing now restricted in deeper water, increased pressure is occurring in the nearshore area. If we don't protect some areas now, the nearshore area will be the next great crisis.

Basically, we need some refuges where fish can grow and reproduce unmolested. They aren't perfect, because fish move, but they work on land for creatures that move. Ducks Unlimited has had great success protecting migratory waterfowl by protecting some critical habitats, even though the birds move and are hunted elsewhere during part of their lives. It's a practical, commonsense idea that works even for migratory animals like ducks and duck hunters are among the strongest supporters (are THE strongest supporters perhaps).

Are you a duck hunter, Brett F? If so, then thank the refuges. If not, then ask a duck hunter about the value of refuges.

Besides, do you really need to fish everywhere? If you can't catch everything you want in 90% of the ocean, why do you think the remaining 10% will satisfy you?

3 comments:

Brett F said...

Mark,
Like I said, I get the theory behind MPA's and there potential to sustain healthy fish stocks. I get that. I won't argue that they can't have a key position in fishery management.
But the MPA process was not a "lengthy processes sought to balance the interests of all concerned"...as you claim.

The MPA process is being promoted like its some great new science method that we all need to embrace, when in fact its been in existence for years. What is not being said is that there already are numerous MPA's on the west coast (80+, refer to the back of the CA Fishing REGS), and these don't include the Rockfish Conservation Areas that stretch the length of the west coast.

That being said, I hardly believe that 10% of the oceans for MPA's are the ultimate goal of many parties involved. I've seen some of the proposals and they include much more than 10%.
Also, it would be great if fish were equally distributed throughout ocean waters, but unfortunately they're not. So your statement that "If you can't catch everything you want in 90% of the ocean, why do you think the remaining 10% will satisfy you?" That's simply an unfair and misleading statement. We could shut down every single mine in the US and it probably wouldn't account for 1% of the land.

Again I stress, additional MPA's will potentially severely restrict very responsible fisheries on the west coast, including dungeness crab, black rock fish, sardines, halibut, pink shrimp, spot prawn, albacore, and one could really argue for salmon, black cod, lingcod, and many more. These fisheries are all success stories of the last decade through ongoing fishery management, including the implementation of MPA's. Yes, it isn't perfect yet, but things are most definitely getting better. Unless you can convince me that people are going to quite eating seafood, if these fish don't come from responsible fisheries like these, folks will continue to get their seafood from truly overfished and unregulated areas, which are amazingly numerous around the world. We need to support our sustainable fisheries, not shut them down.

By closing off more and more areas you are forcing fishermen to concentrate there efforts on the remaining open areas. Then those areas will supposedly become overfished and we'll have to shut them down too.
And when we do we'll all hear about what a great thing this is for our oceans, and people will get voted into office, National Geographic will sell more copies, newspapers will be sold, certain environmental groups will see an increase in donations, and all will be happy. Then the cycle repeats...

MPA's no doubt hold an important spot in ocean fishery management. However, their implementation needs to be done using the best science and resources available, and California's central coast MPA's simply were not.

And don't try to compare ocean management to land management and ducks. Its apples and oranges. You know better than that. Its this type of thinking that contributes to more ocean mismanagement.

Rick MacPherson said...

please forgive my ignorance as i don't even begin to understand the full role of mpa's in temperate waters as my work is focused on mpa's in tropical (coral reef distinations)... but one of the clear lessons we are learning from the data in these areas is the "source" vs "sink" factor of mpa structuring...

in other words, some mpa's are structured to ensure that fish spawning aggregations will be protected to provide the "source" of larvae and future stock replenishment... other mpa's i've worked with are "sinks' for those larvae (ie areas for larvae and juveniles to mature)...

what i haven't seen yet in this discussion thread is any evidence or validity of the spillover effect that effectively structured and scaled mpa's can have on improved fish catch in non-mpa adjacent waters...

we have some pretty compelling data that this works in coral reef associated mpa's, but is this potential viable/verified for the commercially-scaled fisheries off the california and pacific northwest coasts?

Mark Powell said...

Protecting big old fish may be the most important benefit, IMO. We are only beginning to understand the value of BOFFFs and so it's hard to predict precisely.

We know very clearly that life history diversity is critically important for salmon productivity. We mostly have questions for rockfish. How important is diversity in spawning timing? How important is length of larval survival to first feeding? Etc.