Dusting off family photos in the name of science

A typical catch during the late 1960s and 1970s in Key West, Florida. (Photo courtesy of Monroe County Library, Florida)

Photographs of generations of recreational fishermen standing proudly next to monstrous trophy fish catches adorn the pages of family albums across the country. But images like these, once filed away for memory’s sake, are now proving invaluable as historical scientific markers of fish size in coral reef communities over the past fifty years.

“This is the first time photographs have been used in this kind of research,” says Loren McClenachan, a final year PhD student at the Scripps Institution of Oceanography who recently published a historical analysis of fish size declines in Key West, Florida in the June issue of Conservation Biology. “But it is a great way to document species population changes for time periods where ecological and fisheries data are not available.”

McClenachan’s work is part of a larger project studying changes in coral reef ecosystems and species populations over the past 350 years, which she hopes will help set conservation targets for threatened species. During her research, she stumbled upon a collection of historical trophy fish photos dating back to 1956 while combing through the Monroe County, Florida Public Library. The images were taken by professional photographer Charles Anderson over the course of 30 to 40 years and donated to the library’s archives after his death. Combining Anderson’s historical photos with her own images of trophy fish catches from 2007, McClenachan analyzed and measured 1275 trophy fish for her study. The result is a detailed record of fish size declines in coral reef environments in Key West, Florida during the past half-century.

A typical catch in 2007 in Key West, Florida.  Photo credit: Loren McClenachan.

Since the 1950s, the average length of individual trophy fish has decreased nearly 50 cm, from 91.7cm in 1956 to 42.4cm in 2007, and the average weight has dropped from approximately 43 lbs to 5 lbs respectively. The kind of fish being caught has also changed. Gone are the days of hooking sharks and larger groupers. According to McClenachan, today’s recreational fishermen in Florida are mostly limited to reeling in small snappers.

Now that we know those family fishing photos serve a serious scientific purpose, perhaps another researcher will find a use for the shoeboxes of photographs taking up way too much space in my tiny Manhattan apartment.