Where are all the baby lobsters? And if Maine’s baby lobsters are disappearing, does that mean there won’t be any adults in a couple years?
The publication Quartz earlier this month released a long-form research piece on Maine’s lobster boom, which reached another record haul last year with 124 million pounds, a pile of crustaceans worth $456 million and one six times bigger than the state’s lobstermen caught in 1984.
The adult lobster population off the coast of Maine has skyrocketed as the state’s lobstermen have employed a range of practices to sustain the fishery (see the video above). Lobstermen throw back female lobsters bearing eggs and larger males — the ideal fathers — as part of a multifaceted plan to encourage future generations of lobsters.
By all accounts, this is not a case of lobstermen irresponsibly taking advantage of a freak boom and setting their industry up for future failure.
Also helping the explosion are warming waters that are nudging southern New England’s once healthy lobster populations up to the Gulf of Maine and the historical overfishing of natural lobster predators, like cod.
Yet University of Maine expert Rick Wahle told Quartz his researchers have found “a widespread and deep downturn” in the numbers of settled baby lobsters in the area in recent years.
This is baffling on the surface, in part because of all the steps being taken to make sure the lobsters have the greatest opportunity possible to reproduce.
Wahle’s been conducting his annual census of baby lobsters for 25 years, using SCUBA divers and retrievable deep-water habitat boxes to gauge the health of the species at a younger age.
He told Quartz the numbers of babies found in the region have been slumping since 2011.
Although the massive current population of adult lobsters may sustain the industry still for a while, the shortage of babies could begin to ultimately show up as a shortage of adults.
Quartz explores at least three theories for why researchers are finding fewer and fewer baby lobsters, and each carries different ramifications for Maine’s lobster industry.
The Good: The babies are just settling in harder-to-study depths
“In the past, most larvae likely settled in the upper 60 feet or so of the coastal shelf, where waters were sufficiently warm. However, cobblestone and rocky ledges extend a ways offshore in places, perhaps 100 feet down. So as the water has gotten balmier, they’ve been able to make their homes farther offshore — in waters that used to be too cold for them — well beyond where Wahle and his team are looking for them. The kids, in other words, are alright.”
In this scenario, the lobster boom should continue on unabated. The babies are still out there, they’re just not being counted.
“On the bright side, [this] scenario jibes with reports from fishermen who’ve been hauling up baby lobsters and juvenile lobsters in unusually deep waters, suggesting that babies are successfully settling there,” the publication reports.
The Bad: The babies are being swept out to sea
“[UMaine marine ecologist Robert] Steneck says that deeper water — where lobsters spend winter — seems to be warming faster even than shallow areas. If this means a females’ eggs mature and hatch while she is still far offshore, her babies could be carried out to sea by currents into waters too cold and deep for babies to survive.”
Obviously, under this scenario, the lobster haul would begin to tail off. As multiple generations of babies get swept away, huge generational gaps begin to open up in the adult lobster populations, and a time eventually arrives in which the adults are much fewer and farther between.
The Ugly: Females are becoming less fertile
According to Quartz, University of North Carolina biologist Melissa Koopman has been studying the fertility of lobsters off Nova Scotia’s Grand Manan Island, a “spawning hotspot for the whole region.”
Koopman’s team counted the eggs on nearly 1,400 egg-bearing female lobsters over a five-year period, and found the numbers of eggs per lobster mom decreased by about 30 percent from 2008-2013.
Koopman hypothesizes that the decline in eggs can be blamed on the same warming waters that are carrying the lobster populations northward.
“While some warming is obviously favorable to lobster populations, too much is dangerous. A female lobster’s ovaries mature when temperatures drop somewhere below the 41°F to 46.4°F range,” the report reads, in part. “During the five years of the study, water temperatures never fell below 41°F, and only a few times below 46.4°F. If Koopman and her teams’ hypothesis is right, it also doesn’t bode well for egg production further south, in waters already much warmer in winter than the Bay of Fundy.”
Another theory for why the egg counts are lower is that, even though larger male lobsters are also getting thrown back, there still aren’t enough of them to be mates for all the females being thrown back. Under this theory, the males’ virility and potency is being stretched too thin to support the numbers of eggs found in previous years.
The “water is too warm” hypothesis is worse for the industry than the “there aren’t enough men around” theory — there are easier ways to get more father lobsters back on the dating scene than there are to reverse the temperature climb of ocean waters, at this point.
All of the theories for why fewer baby lobsters are being counted are just theories, albeit educated ones. They may be only proven or disproven by future years’ lobster catches. Continued record hauls likely mean the babies are just out of studying range. A dropoff in annual hauls means something more serious is going on.