Sharks, Shifting Baselines and the Oil Spill

Linked off of Ahab’s Journal is this interesting and very thorough article about the state of shark management in Florida.  I won’t try to summarize the whole thing and it’s definitely recommended reading, especially since it’s one of the most even-handed reviews of Florida’s shark fishery that I’ve read.  What I wanted to comment on is the short memory people seem to have with regards to natural resources in general and the ocean specifically (usually referred to as the shifting baselines phenomenon).  In the case of Florida’s sharks, at least some of this has a connection to the Deepwater Horizon oil spill.

The article covers the usual disconnect between scientists and fishermen when it comes to the perception of shark stocks.  As Dr. Bob Heuter stresses, shark declines are “like global climate change, you’ve got to look at the trend over time.”  However, representatives of the fishing industry point to locations like Boca Grande (site of the #1 shark video on YouTube according to yours truly) where bull and great hammerhead sharks are locally abundant during tarpon season.  That said, just because sharks are abundant near a source of food doesn’t mean they haven’t declined throughout their range; it just means that a large chunk of the remaining population is in one place at the same time (which can make them especially vulnerable).

This is becoming especially true in the Gulf of Mexico, where the lingering effects of the Deepwater Horizon spill have caused many of the Gulf’s sharks to seek refuge closer to the beaches of the Florida panhandle.  According to the article the high numbers of sharks in the area have been cited by fishermen as a sign that shark populations are booming on the Gulf coast, when in reality it just means that more individuals are in a smaller area.

We humans have an amazing (and potentially dangerous) ability to accept whatever is happening in front of us at the moment as the “way things will always be.”  This is why catching small grunts in areas where people used to get large grouper is considered a good fishing day, and why a single bad snow storm is apparently a sign that global warming isn’t happening.  This works both ways: conservation “victories” can actually be ecological disasters if proper thought isn’t given to the big picture.  As scientists, fishermen, stewards of nature and users of natural resources, it is imperative that we learn to adopt a longer-term point of view.


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  2. Robert Wilson · October 17, 2010

    thanks for the post

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  4. Mike Lisieski · October 17, 2010

    It is often very hard to get people to understand the concept of shifting baselines, precisely because it goes against their “common sense”. It’s an unfortunate thing (as you well know.)

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