Historical Photographs Expose Decline in Florida's Reef Fish, New Scripps Study Finds

[OKIsItJustMe]

http://scrippsnews.ucsd.edu/Releases/?releaseID=959

Tuesday, February 17, 2009

Historical Photographs Expose Decline in Florida's Reef Fish, New Scripps Study Finds

Snapshots trace shrinking 'trophy fish' over a generation of sport fishing

Scripps Institution of Oceanography / University of California, San Diego
A unique study by a scientist at Scripps Institution of Oceanography at UC San Diego has provided fresh evidence of fishing's impact on marine ecosystems. Scripps Oceanography graduate student researcher Loren McClenachan accessed archival photographs spanning more than five decades to analyze and calculate a drastic decline of so-called "trophy fish" caught around coral reefs surrounding Key West, Florida.

In a paper published online in January and printed in an upcoming issue of the journal Conservation Biology, McClenachan describes a stark 88 percent decline in the estimated weight of large predatory fish imaged in black-and-white 1950s sport fishing photos compared to the relatively diminutive catches photographed in modern pictures. In a companion paper being published in the Endangered Species Research journal, McClenachan employs similar methods to document the decline of the globally endangered goliath grouper fish.

"These results provide evidence of major changes over the last half century and a window into an earlier, less disturbed fish community..." McClenachan said in the Conservation Biology paper.

McClenachan's studies are part of an emerging field called historical marine ecology, in which scientists study photographs, archives, news accounts and other records to help understand changes in the ocean ecosystem over time and establish baselines for future ecosystem restoration.

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Trophy fish caught on Key West charter boats: a) 1957, b) early 1980s and c) 2007.

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[fasttense]

1. It is simple evolution.

Since the big fish were getting killed, it left only the little ones to reproduce. Eventually, all you get is little fish. Too bad it doesn't work that way in economics.

[MineralMan]

2. Fishing yields have declined everywhere, marine and freshwater

alike. Overfishing is part of the reason, but there are others, including pollution.

In Minnesota, where fishing is a religion, is affected by all of this. The natural response is that there are now fewer anglers, so there has been some rebound. The increase of catch-and-release angling is also benefitting the fish population.

In addtion, for people like me, non-game species, like carp, have become viable alternatives. Since I'm a catch-and-release angler, it doesn't matter to me. A 10 lb. carp is a decidedly fun fish to catch. I release them, too, even though they are a non-native species here.

On a global scale, though, the decline in our fisheries is a serious problem, since fish are important food sources.