So this is cool: Google earth comes to the rescue again! But first, I'm going to blab about fisheries for a while.
You know what's weird when you actually think about it? Fish are one of the last major food sources that we rely on a hunter-gatherer (ok, a fisher) approach to supply commercial markets. Everything else, we farm, and while we are increasingly reliant on farmed fish, we still gather millions of tons/tonnes of fish protein from the oceans each year.
And you've probably heard that many fisheries (the global stock of one species) are nearing collapse (Figure 1), where their reproduction will no longer be able to keep pace with our consumption. So we gotta regulate, right? Yeah, but it's hard(1)! In addition to the fact that, on a global scale, fisheries management is a tragedy of the commons type of problem (2), in order to say how many fish we can get away with removing from the sea (right? because it's not realistic to to STOP fishing entirely), we have to know how many fish are out there.
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| Figure 1. Ack! Fishes disappearing! Over the past 60 years, the rate at which fisheries have been considered to have "collapsed" has increased. From Worm et al. 2008 Nature (Diamonds, collapses by year. Triangles, cumulative collapses, inset map shows fish diversity) |
This sounds simple but it's not. There are literally hundreds of EXTREMELY smart people, in this country alone, trying to figure out how to figure out how many fish there are. Part of it is biology: Fish live in an incomprehensibly vast (ok, that's hyperbole, we can actually put a number on how vast) ocean that transcends national borders, and populations respond to complex global-ecological factors in natural cycles, like El Nino/ENSO, Pacific Decadal Oscillation, and sweeps week.
The other part is the human factor. One way we try to tell how many fish there are is by counting the fish we catch and eat. This relies on people telling fisheries biologists the truth - and it turns out that is not as straightforward as it sounds (sensing a theme here?). Many countries don't have the resources to accurately count how many fish they catch, but some that do...still don't accurately report how many fish they catch.
BUSTED! By Google Earth (Figure 2).
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| Figure 2. Oh, don't worry, FAO people won't come to the UAE to check on our catches, just make a number up! Satellite image of a fishing weir in the Arabian Gulf. This is a passive fishing trap, that strands fish in the trap when the tide goes out, allowing humans to walk out and pick em up. |
Researchers at the University of British Columbia, including Fisheries Collapse Hotshot Daniel Pauly, used Google Earth to identify a major source of missing fish reports, weirs in the Persian Gulf (read all about it). So, ok, how big a deal can some fish traps be? Researchers estimated that the 1900 traps they saw from space caught 31,433 tonnes per year of fish! That's six times what was reported. Yeah, that makes it pretty hard to figure out how many fish and crabs are left in the ocean.
References and Miscellany:
(1) Here is where I acknowledge that, similar to every other environmental problem we face as humans, there are those who don't believe fisheries are indeed in jeopardy. Or, to be more fair, this is a contentious topic, with some arguing that projections of collapse are overstated. While I am not a fisheries biologist, I am acquainted with the literature, and the researchers who are, and am firmly convinced that there is more than enough evidence to demonstrate that we are, indeed, at risk of overexploiting most of the resources from the ocean. Here are some resources that I have found interesting, and at least somewhat balanced:
(2) What, primarily literature isn't entertaining enough?! That was a huge seminal paper in environmental ethics! OK Fine, Here is a talking head explaining the tragedy of the commons with cartoons.
