MDE Investigator Pins Calvert Cliffs Fish Kill on Recreational Fishermen

I already reported the fish kill, as well as my own thoughts, but now, at the BayNet: Dozens Of Dead Fish, Crabs And Birds Wash Ashore At Calvert Cliffs State Park In “Nexus Event”

The MDE investigator, Chris Luckett, agreed that winter die-offs of fish are rare. In this case, he attributed the deaths of multiple species to a “nexus” event — or a combination of factors that led to the deaths rather than a single incident. The birds, he said, may indicate some kind of disease. Blue crabs, on the other hand, do occasionally experience winter die-offs. It’s not common, but has been documented in cold winters. Crabs spend their winters dug into the sediment in the bay — those who chose to do this in shallow waters are more vulnerable.S

The fish deaths were where Luckett’s investigation took an unusual turn. Luckett, an investigator of 26 years who has personally worked on more than 500 fish death events, said he first looked for evidence of disease. He also looked for injuries that could indicate that fish were caught in a commercial fishing net.

Did he look for holes in their lips from being hooked? Fish lips heal fast, but not that fast.

Finding neither, Luckett moved on to water quality issues. He took water samples and was able to rule out low oxygen levels, algae blooms and pollution.

The most likely scenario, Luckett said, was that fish suffered from temperature stress related to catch-and-release fishing. He said that the water temperatures vary in certain spots in the bay. On a few key warm days in February, people took to the water for recreational fishing. During that process, they released fish into colder waters than the ones in which they were caught. A sudden temperature change, even of just a few degrees, can be a huge shock to the fish’s system.

Obviously he's talking about Calvert Cliffs Nuclear Power Plant, one of a few warm water discharges in the Bay, and the only one in the vicinity of the incident.

“A lot of times, you walk down to the scene of something like that, and you see they’re all dead. And the simplest explanation is that they’re all related, but when you investigate you come to understand it’s not the case. We can say now that it’s scientifically correct to say they’re not connected events,” Luckett said.

Luckett is confident in his findings about the fish kill event. The waterfowl death event is being investigated by the Maryland Department of Natural Resources.

“This is how it gets done at MDE,” Luckett said. “It’s based on strong science and evaluating the evidence to come to a conclusion.”

I am very skeptical of this explanation. Of course, I'm biased, as a person who has fished the warm water discharge at CCNPP. But let me explain. CCNPP is allowed to release water 10 F warmer than the water they take in. However, the outflow has a tremendous mixing effect (there's a lot of motion), and it is very rare to actually find water there more than 5 F warmer than the surrounding area. I don't really think that a 5 F temperature difference is enough to cause shock to a big Striped Bass. As an aquarist, I would try to avoid a 5 F temp shock, but I wouldn't be super concerned. Stripers move in and out the the discharge area all the time. They're looking for food, not heat. And how does he account for the dead Toadfish shown in the article? It certainly wasn't a victim of catch and release angling. Once in a blue moon a toad hits a lure intended for a striper, but I've never seen it in winter. 

That's not to say that catch and release angling doesn't kill some fish, it does, but only rarely in cold water. Once in a while, a fish sucks the lure down its throat or into to gills, and extraction causes considerable damage. However, that's pretty rare, probably way less than 10%.

So rather than use Occam's Razor to connect dead fish, dead crabs and dead birds to the extremely cold weather prior to the event as the explanation, he managed to concoct 3 different explanation for why fish, crabs and birds washed up simultaneously. There is a faction at DNR which seeks to restrict recreational fishing. I hope this isn't enemy action.