The Michigan Department of Natural Resources (DNR) published a story a few days ago that made many people upset. As someone who has her feet in both natural resources management and public relations/science communication it offers an interesting case study. The DNR was trying to highlight an interesting fact about how fish can reach old ages, but some mistakes got in the way of this message.

The ear bone of one fish they caught in a special survey done in 2023 to study the different forms of lake trout and their reproductive biology was recently analyzed and the DNR discovered that the fish was as old as I am! (62 years) They caught the lake trout on a reef in the southeastern part of Lake Superior (40 miles north of Grand Marais, Michigan) and this lake trout is the oldest one currently on record.

The ear bones of fish show annual rings much like a tree, and that’s how the DNR can tell the age of the fish. It’s the only way they can do this, and they have to kill the fish to extract the ear bone, also called an otolith

One mistake the technicians made was naming the fish. They picked the era-specific moniker of Mary Catherine because Mary was one of the most common names in 1961 when the fish was hatched. People who heard news reports were excited that such an old fish was found, and that it even had a name, only to be crushed when they learned later that the fish was killed in the process of discovering its age.

One Facebook commenter said, “Hey we just killed Mary Catherine, but the upside is we now know that she was 62 years young, much like many grandmothers and recently retirees. There’s one less on Social Security now, and that should help keep it solvent.”

Another said, “Sad that they killed a fish who is probably older than the combined ages of some of the researchers, but it is interesting information.” Another commented that the fish might have lived another 20 years if not sacrificed for science.

You might think that such an old fish would be very large, but she wasn’t. Mary Catherine weighed 2.1 kilograms (4.62 pounds) and was 627 millimeters (24.7 inches) long. That’s because Lake Superior doesn’t have much food in it and animals grow slowly. The typical lifespan for a lake trout is 25-30 years.

The story gained wide media coverage, so it was successful that way, but even some of the reporters were dismayed that Mary Catherine was a goner. People already love to hate the DNR, and this well-intentioned science story just gave them another reason.

I’d say the main lesson is not to name your research subjects in newsworthy stories, especially if they’re dead.

The researchers were mum about whether they were inspired by the Saturday Night Live character, Mary Katherine Gallagher.