December 4, 2012
Maine Lobsters Are Cannibals: They Eat Their Youngsters
[Watch Video: Lobster Cannibals Captured On Film Along Maine Coast]
Brett Smith for redOrbit.com - Your Universe Online
Lobsters have long been known to attack and eat each other within the confines of a trap or tank, but scientists from the University of Maine have captured new video evidence of adult lobsters eating their younger counterparts in the wild.
The Maine researchers speculated that the exploding lobster population off the coast of the Pine Tree State is the primary driver of this never-before-seen behavior.
"We've got the lobsters feeding back on themselves just because they're so abundant," research team member Richard Wahle, a marine sciences professor at the university, told Reuters. "It's never been observed just out in the open like this.”
He noted that a group of Canadian researchers had recently observed evidence of cannibalism in the stomachs of wild-caught lobsters from the same region.
"There are these cases where encounters with each other are becoming so frequent, they result in more than just a bit of competition but in a predator-prey interaction," Wahle added.
In their experiment, the researchers set out to observe the predation of small lobsters, which they tethered with a rope to the sea floor. Using a special infrared camera, they expected to see larger fish prey on their bait.
"We were hoping just to see that maybe they were being untouched or that perhaps there were still fish and maybe there was just a different predator assemblage," co-researcher Noah Oppenheim, a graduate student at the school, told the Portland Press Herald.
During the daylight hours the team observed exactly that–large predatory groundfish attacking the small lobsters. However, at night, they observed the majority of attacks on their small lobsters were by bigger lobsters.
The team repeated their experiment several times and each time watched as bigger lobsters preyed on, and fought over, the smaller lobsters.
"The population of lobsters in Maine has skyrocketed and there have been some interesting changes in abundance, demographics and, we believe, behavior,” Oppenheim told Reuters. "Eight out of nine times at night, predation is due to cannibalism."
The overabundance of lobsters has driven up business in the lobstering industry, with lobstermen hauling in 104 million tasty pounds last year. By comparison, the total catch for 1981 was 23 million pounds and this year´s total is expected to be the highest ever.
Many cite overfishing of lobster predators, including cod, halibut and other groundfish, as the primary cause for the booming lobster population. Climate change factors warming waters in the Gulf of Maine may have also bolstered the population, despite the possibility that the same phenomenon has equated to more disease and blight in Long Island Sound and southern New England, according to Wahle.
Despite the fact that the rapidly expanding lobster population has created a boom for the industry dedicated to their catch and sale, the overabundance has caused problems, including a border battle with our neighbors to the north.
In August, Canadian lobstermen frustrated by falling lobster prices temporarily blocked shipments of cheap Maine lobster that were being brought into Canada for processing.