Saturday, July 30, 2005

Scientists Warn Fewer Kinds of Fish Are Swimming the Oceans

A curiosity in the new report on a decline by half since 1950 in fish species diversity in the world's oceans ---Scientists Warn Fewer Kinds of Fish Are Swimming the Oceans - New York Times--is that one of five "hotspots" bucking the trend is said to lie off Florida's populous and long over-fished east coast. These hotspots aren't closely identified in the original article in Science Express, but this one lies in and around the deep, warm waters of the Gulf Stream, flowing not that far off the peninsula's shores. Boris Worm and his co-authors used deepwater predators, tuna and billfish, as models and attemped to identify what factors helped determine the location of hotspots, the density and diversity of species. They identified such factors as oxygen in the water, oceanographic dynamics--for example, the interplay between the waters of the Gulf Stream and bordering ocean--the amount of zooplankton, and the climate. The idea is to preserve these areas in the hope of replenishing stock, not calling the attention of fishermen to them.

Previous surveys have shown that protecting fish from humans for enough years for populations to recover actually makes for better fishing in the long run. A model for this, albeit one that is near shore rather than out to sea, is the area around Merritt Island, Florida, protected because of the Kennedy Space Flight Center at Cape Canaveral. The tidal lagoons are relatively lush with fish, as a result.

Habitat destruction and overhunting or overfishing are the primary causes for the sharp decline in species, especially large mammals, birds, and game fish. If the habitat of a specialized animal is destroyed, so is that animal, of course. Thus, the continued, rapid conversion of Florida scrub into sprawling ex-urban residental developments threatens the gopher tortoise, indigo snake, and several other species, while also screwing up replinishment of the freshwater aquifers underlying the peninsula. Those are major problems that require strict habitat protection.

But in many other cases, people simply need to give the animals a break--to stop killing them and learn to share with them. The late Dr. Bill Robertson, for decades the resident wildlife biology guru at Everglades National Park, liked to say that if we stopped the killing of any animal, including large predators, it usually learned to live with us quite well. Too often, it's the humans who can't make the accommodation.

It's past time we leave the bulk of the world's remaining fish alone. Seafood Watch provides a catalog of marine life worldwide and ranks it according to whether it can responsibly be eaten--that is whether it is in good supply or is overfished, raised in environmentally disastrous aquaculture, or made toxic by pollutants. Visitors to their website can download printable guides that fold up to fit in your pocket. There are some delicious fish on the avoid list, including all snapper, but if we don't stop catching and eating them now, they won't be around for anyone.

Storm gathering, the dogs are being obnoxious. It's their play time, and so they're antsy to go, but they don't like the thunder.

2 comments:

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Retrieverman said...

Not only are there fewer kinds of fish, but the fish that do exist are getting smaller:

1. Due to climate change: http://www.bloomberg.com/apps/news?pid=20601090&sid=aJZZoBNdKIN8

2. Due to overfishing: http://www.mindfully.org/Heritage/Fish-Are-Smaller-Overfishing.htm

We can only imagine the number of fish that once existed in the seas off this continent. And we can only imagine their size. When I read accounts of giant sturgeon in rivers on the East Coast and of rivers that once were filled with salmon, you can't help but think about how horribly stupid we have been.