Stony Brook researcher says sunlight might induce scallop spawning

A scallop gapes open in the air, showing off the 50 to 100 blue eyes ringing its lips. (Osborne, 2018)

By Taylor Beglane and Margaret Osborne

An ecologist at Stony Brook University is testing a new hypothesis that could change the way conservationists nurture Long Island’s scallop population. In his most recent experiment, Professor Nils Volkenborn found that sunlight may prompt scallops to spawn, and not temperature as fish farmers and scientists believe.

Volkenborn has been doing experiments in Orient Harbor over the summer by attaching infrared heartbeat sensors to scallop shells to detect changes in their heart rate. Heart rates, he found, spike when the scallops spawn.

Most scallop farmers increase temperature to initiate spawning. But during Volkenborn’s latest experiment, he discovered that two groups of scallops in different locations spawned at around the same time of day, even when temperatures dropped because of the incoming tide. This suggests that time, not temperature, plays an important role in reproduction.

“It would make sense,” Volkenborn said. “This (time) is probably the most reliable trigger that you can think of.”

It’s still unclear which environmental factors trigger the spawning. Volkenborn and his students will spend another month monitoring the scallops before analyzing the data they have collected.

Working in conjunction with Long Island University professor Steve Tettelbach, one of the initiators of the Peconic Bay Scallop Restoration Project, Volkenborn has been tracking sixteen scallops in lantern nets attached to long lines in Orient Harbor since the beginning of the summer, which, he claims, is the longest running monitoring of invertebrate heartbeats in real time. Last year, Volkenborn approached Tettelbach about collaborating on this project.

“I was really excited,” Tettelbach, who has been working with the Scallop Restoration Project for over 30 years, said. “It’s kind of a different way of looking at things. I’m an ecologist, so I’m looking at, not individual animals, but populations of a whole system.”

The restoration project is responsible for the growth of the scallop population on Long Island. In an experiment in Southold, the project found that manipulating sunlight also affected scallop reproduction, further supporting Volkenborn’s hypothesis, Tettelbach said.  

“We’re hopeful that we’re going to get good information about what their spawning patterns are,” Tettelbach said. “That’s kind of a mysterious thing in their life cycle.”

In 1985, bay scallop populations first declined in Long Island because of brown tide, a harmful algae that is too small for the filter-feeding scallop to absorb. Brown tide also outcompetes other algae species that scallops could feed on.

Brown tide has been linked to high nitrogen levels in the water, which fills it with nutrients that spur algae blooms. Nitrogen from Long Island septic systems and fertilizers enters the bay with groundwater and rain runoff from land.

The Peconic Bay Scallop Restoration Project has been helping scallop populations recover after a brown tide decimated their numbers since the 1980s. In 2005, the project began growing the scallops in massive numbers in hatcheries and releasing them into the bays. Scallop populations in the Orient Harbor area have skyrocketed by over 1,000 percent, contributing $5 million to fishing industries and $45 million to the local economy, according to the Cornell Cooperative Extension.

“It’s very nice, because scallop fisheries have a long tradition on Long Island,” Volkenborn said of scallop fishing. “If the local people can continue to do this, they really appreciate the nature, so I think it’s a good thing.”