Backyard Nature: No red herring

by Marjorie Rachlin

Blueback herring (scan of illustration by Duane Raver, courtesy of U.S. Fish and Wildlife Service)

Did you know that herring come up Rock Creek to spawn this time of year? Blueback herring and alewives, males and females, leave the ocean every spring. They swim up Chesapeake Bay, then up the Potomac. It’s part of an annual migration that happens in the rivers all along the East Coast. On April 27th, 2012, 50,000 alewives went up the Mianus River in Connecticut after a heavy rain.

When ours get to the Tidal Basin, they start sniffing for fresh water, and if the mixture smells right at the mouth of Rock Creek, some of them will come up our way.

The dam at Peirce Mill has a fish ladder that herring can use to move upstream.

At Peirce Mill, they must go up the fish ladder at the dam. Further up the Creek, the females will release eggs and the males will fertilize them. Unlike salmon, the adults don’t die. They just turn around and head back to the ocean. The hatchlings spend several months in Rock Creek, washing down into the Potomac in late summer.

My husband used to fish in the Potomac, under Chain Bridge, and he says during some springtime spawning seasons there were so many they were easy to catch. Small (7 inches), full of bones and definitely not tasty, he says. Just as well – fishing is not permitted in the DC part of Rock Creek north of the Zoo.

So far this spring the water level is so low in Rock Creek that these fish have stayed in the Potomac. The experts at the DC Fisheries office say it will take a huge rainfall to bring them up. If that happens, the fish ladder at Peirce Mill is the place to see them jump.