Fish Detectives

  • The fish detectives (a.k.a. scientists who specialize in fishery genetics) survey the scene. (Photo courtesy of the Lake Erie Center)

On television, the CSI detectives make forensic lab work look glamorous. It’s a cinch for them to track a criminal by the DNA left behind at the scene. In real life, DNA is also a powerful tool for solving environmental crimes and mysteries. Rebecca Williams visits the Fish Detectives:

Transcript

On television, the CSI detectives make forensic lab work look glamorous. It’s a cinch for them to track a criminal by the DNA left behind at the scene. In real life, DNA is also a powerful tool for solving environmental crimes and mysteries. Rebecca Williams visits the Fish Detectives:


(Sound of gulls and reel being cast)


It’s midday, and it’s so hot the gulls are just standing around with their beaks open.


But Joe Al-Sorghali is still trying to get himself a fish dinner:


“Hopefully I can get a good amount of perch today… they’re not that fishy so they’re a really good catch.”


It takes a lot of these little fish to fill up a dinner plate. But that doesn’t stop Al-Sorghali from going after perch and walleye any chance he gets. A lot of people call Lake Erie the Walleye Capital of the World.


Fishing is a really big deal here. So it makes sense that Lake Erie’s also home to the Fish Detectives.


(Dragnet theme music)


The fish detective headquarters is tucked away on the edge of a quiet cove. The investigators at the Lake Erie Center are not wearing trench coats. They’re not even wearing lab coats. This crew of laid-back lab techs and grad students comes to work in jeans and T-shirts.


Carol Stepien heads up the fish detective squad. She says they solve lots of cases of mistaken identity.


Take the Case of the Fried Perch.


Last year the detectives got a call from a TV station in Milwaukee. The news crew was suspicious that the fried local perch on restaurant menus wasn’t really local.


Stepien says she asked the news station to send her some frozen filets.


“So instead they sent their news crew out into restaurants and had their news crew eat the fish and put a little bit of the breaded, cooked fish in a plastic bag and froze those and sent them to me. We were pretty shocked to get those in our laboratory. We didn’t know if we could get DNA from breaded, fried material like that.”


But Stepien says they scraped off the breaded coating… and they actually were able to extract DNA from the little bits of cooked fish.


“And we found that about half of those fish were yellow perch from Europe.”


Stepien says it’s gotten more common for fish brokers to import yellow perch from outside the U.S. because it’s cheaper. She says even though the foreign perch might taste the same when they’re deep-fried… a close look at the DNA of the European yellow perch reveals big differences from Great Lakes yellow perch.


“They probably could be called freshly caught lake perch, but they were certainly frozen and didn’t come from any local lakes, they didn’t come from the Great Lakes. Instead they came from overseas.”


Stepien’s team will tackle any sort of mystery, as long as it involves gills and fins.


Lately they’ve solved cases of home invasion. That is, invasions by exotic species that’ve gotten into the Great Lakes. The scientists can track the invaders by their DNA fingerprints, and find out where they’ve been.


Joshua Brown is a Ph.D student at the lab. He’s been tracking the round goby. It’s a fish native to Europe. Scientists say it caught a ride to the Great Lakes in the ballast tanks of ocean going ships. It’s been crowding out native species.


“We’re going to find somebody to point the finger at, as it were. We’ve found evidence they came from the northern portion of the Black Sea, right around one of the major ports.”


That port is in Ukraine. Even though they’ve found the culprit, Brown says there’s not much governments can do, because everyone’s guilty.


“I don’t think you could really sue a nation for you know, not keeping their species under wraps. If so, we’d be open for a lot of lawsuits too – we export almost as many as we import.”


But Brown says knowing exactly where a foreign species comes from might help keep the door closed to future invaders from that same region.


Whether it’s a case of consumer fish fraud or defending the home turf from invaders, there’s one bottom line for these detectives. They want to find out as much as they can about native fish so they can keep them from going belly up.


For The Environment Report, I’m Rebecca Williams.

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