What Affects Clam Productivity on the Mudflats?

Dr. Brian Beal, biology professor at the University of Maine Machias, has been studying this question over the last few years. Generally, the number of bushels of clams harvested from any particular flat measures productivity. However when numbers are low, the beds are thought to be “dead.” Dr. Beal suggested if the juvenile clams could be counted, while being protected on the flats, there would be a better understanding of the possible impacts to settlement and recruitment. He devised recruitment boxes that are placed on the flats in the spring before clams spawn, and are left on the flats until after spawning in late fall. [Read Dr. Beal’s research proposal for the clam recruitment study.]

Dr. Beal conducted such an experiment in 2017 on the upper tidal portions of the St. George River and Weskeag River. The Georges River Land Trust provided access to the flats over the Riverview Hayfields Preserve. In mid-June, he placed 15 boxes on GRLT property, and 5 boxes each in two other locations on the St. George River. He additionally placed 5 boxes on the Weskeag River.

On a bright and warm October day, Dr. Beal came down with one of his staff from the Downeast Institute to collect the recruitment boxes from the mudflats, process the sample boxes and return to the Institute to determine the number of species per sample as well as the number of individuals of the various species found settled in the mudflats. Outside of each recruitment box, he collected core samples in the mud, which will allow him to compare recruitment success.

In early 2018, Dr. Beal will have results that can help shed light on what affects clam productivity on the flats, whether it be predation, ocean acidification, or warming temperatures. The Land Trust is pleased to offer our preserve to advance our collective understanding of clam productivity on the St. George River.