WELLS — After a mother lobster hatches her eggs, her larval lobster offspring will start off the initial stages of their lives by floating along the surface of the sea for about two to four weeks. Researchers at Wells Reserve are trying to figure out where the ocean currents may take them from there.
For the past two summers, scientists at the research facility in southern Maine have been releasing ocean drifters – a box-kite-looking buoy that flows with the ocean currents and reports its position every 30 minutes – to see how the seas move at a local level and where the planktonic lobsters may be going.
Last summer, research director Jason Goldstein and his team at the Wells Reserve released 24 drifters around the time when lobsters hatch, some near shore and others as far out as 16 miles. Seven more were released this July.
The team tracks the drifters between three weeks and two months to better understand the ocean currents and how hatching locations affect lobster dispersal.
The drifters aren’t a perfect representation of lobster larvae, which get better at swimming as they get older, but they can give an approximate idea of where the lobsters go.
“We’re using the drifters as a proxy,” Goldstein said.
He hasn’t analyzed the data yet, but generally drifters that were released farther offshore tend to stay offshore and lobsters in the shallower areas near shore can sometimes drift offshore or move in a southeasterly direction.
“There’s a fair chance if you have lobsters hatching in southern Maine, those lobsters end up in Massachusetts,” he said.
All the drifters were released in southern Maine and the work was localized to that area. While there’s been a lot of great work around oceanography in the Gulf of Maine, Goldstein hoped that this would help drill down to a local level, giving more intimate data that could be useful to lobstermen.
Goldstein wasn’t sure how the same type of study would pan out in the Midcoast or Downeast.
This data will give Goldstein and the other researchers at Wells an idea of how far post-larval lobsters must swim to get to their nursery grounds, which ties into another ongoing study at the reserve.
The post-larval stage is the last development stage before the lobsters settle on the seafloor. Lobsters will swim near the surface to the coastal nursery habitats, with their claws outstretched like Superman.
But there are concerns about how rising water temperatures and increased acidification affect their swimming. As the ocean warms, the lobsters could burn through their energy reserves sooner, meaning they may not be able to swim as far.
Goldstein and his colleagues have been studying the swimming abilities of the lobster – work that will go hand in hand with the drifter study.
In a sort-of lobster larvae exercise wheel, the researchers are testing how long the lobsters are capable of swimming at different temperatures and how much energy they have left over.
“There’s not a lot known about how far they can swim,” Goldstein said. Initial findings show that increased temperatures make it tougher to swim longer distances. “We’re kind of in the early stages of this, but not too unexpectedly, the warmer the water, the harder it is for them to maintain strong swimming capability.”
As of late, there has been a larger emphasis on learning about the larval stages of the lobster species to help make better management decisions down the road. For a species so important to the state, there is still a fair amount unknown about these initial parts of a lobster’s life.
Scientists in Maine are also trying to find out what larval lobsters eat – an important piece of information if there are changes in the nutrients in the ocean.
“It’s kind of mind blowing to me after all these years,” he said. “Some of the most basic things we still don’t know.”