Maine fishermen hauled in 110.8 million pounds of lobsters in 2017 with a value of more than $400 million. While still incredibly large, this volume represented a 16 percent decline and $100 million loss compared to previous years of record-setting landings.
Since the late 1980s, Maine’s lobster landings have multiplied sixfold, while the area of highest landings has shifted Down East to Hancock and Washington counties. The U.S. lobster fishery is now the nation’s most valuable single-species fishery.
But last year’s decline was the largest in more than 50 years, leading the industry and scientists to wonder whether the boom has come to an end.
“The other possible reason for the decline is that larval settlement has spread out across a larger range of depths, effectively reducing settlement densities in the routine shallow-water monitoring locations.” Richard Wahle
The patterns are consistent with forecasts based on juvenile lobster population surveys founded and overseen by professor Richard Wahle in the University of Maine School of Marine Sciences.
In 1989 with support from Maine Sea Grant, Wahle initiated data collection for the American Lobster Settlement Index, a program that monitors the number of baby lobsters that “settle” to the sea floor every year. Counts are made at some 100 sites from Rhode Island to Atlantic Canada. While the monitoring is now conducted by participating marine resource agencies in the U.S. and Canada, Wahle’s lab hosts the collective database, developing and testing the index as a forecasting tool.
There are two prevailing explanations for such little settlement, he says. One is that more larval lobsters are dying before they reach the settlement stage. The other is that they are spreading to new deepwater nursery grounds not covered by current monitoring efforts.
To understand settlement in deepwater out of reach of standard diver-based sampling, Wahle received funding from Maine Sea Grant in 2016 to expand the settlement survey to deeper water. His aim is to examine links between temperature gradients and lobster settlement, both depth-wise and along the coast.
Working with research partners and lobstermen, preliminary data confirm that newly settled lobsters are as deep as 80 meters and in different settlement patterns east to west. Industry partner Ready Seafood has provided funding to continue deepwater settlement monitoring through 2019.