A lobster boat leaves Point Judith in the dark with an extra passenger and an empty cooler.
The traps that come up are ventless wire, which means nothing can crawl back out of them.
What lands on the sorting table is mostly crab, and every second week somebody takes a piece of one home.
A shell chip and a muscle sample, from 10 fixed stations around a wind farm.
The question those samples are meant to answer is worth a lot of money to the boats hauling them.
A shell chip and a muscle sample
The work is being done by a doctoral student in biological oceanography at the state university, working under an oceanography professor who runs the laboratory.
He rides the boats out of Point Judith twice a month and takes his catch back to a laboratory that reads chemistry rather than counts animals.
The method is stable isotope analysis, and the trick is that different tissues record different windows of time.
A crab’s shell holds the chemical signature of where it was when that shell was laid down.
Its muscle records what it has been eating far more recently, so the two together separate a resident from a visitor.
In his own words, the map in the shell can tell him whether the crab was there when it was born.
The crab nobody used to keep
For most of the last century Jonah crabs came up in lobster traps and went straight back over the side.
Lobster was the money. The crab was an obstacle in the pot.
Then the southern New England lobster stock fell away, and boats that needed a second species looked down at what they had been throwing back.
Landings rose by roughly 669 percent between 2000 and 2017, and a management plan for the species was finally adopted in 2015.
Almost all of it comes from one place. The offshore southern New England stock accounted for 70 to 85 percent of coastwide landings across 2010 to 2021.
It is also the only part of the range where crews go out deliberately for crab rather than catching it beside lobster.
What steel does to sand
The seabed out there is mostly sand and mud, with very little hard surface for anything to grip onto.
That matters because a crab does not want open bottom. It wants edges, gaps and something solid overhead.
A foundation changes that the moment it is in, and the first arrivals are blue mussels and barnacles.
At the five turbine site off Block Island, one foundation carried mussel beds up to 20 inches thick by its third year.
The seabed community around that leg flipped from being run by worms to being co dominated by barnacles and mussels, a habitat type not previously recorded in those waters.
Mussel patches turned up as far as 160 feet from the leg, and further out beyond the survey area entirely.
Yet between 100 and 300 feet out the sediment itself barely changed, which is the detail that keeps the question open.
Which turbines are actually involved
Two projects sit at the center of this, and neither of them is the famous first one everybody names.
South Fork Wind put 12 turbines and 132 megawatts into federal water about 19 miles southeast of Block Island, delivering first power in December 2023 and running fully by the following March.
Revolution Wind is the larger one, 65 turbines and 704 megawatts, and it began feeding the grid in March, as the project describes.
That is a lot of new hard bottom arriving on a shelf that had almost none, over a handful of years, and more of it is going in.
Meanwhile the fishery it lands in is under real pressure, with catch per unit effort falling and 2023 landings down 12 percent by weight and 36 percent by value, as the assessment records.
The same accounting question follows every offshore array and every fenced solar site, which is whether the wildlife arrived or simply relocated.
Why the answer changes the rules
Two things can produce identical trap counts and mean opposite things.
If the foundations are growing new crabs, the stock is genuinely larger and the fishery has room it did not have.
If they are pulling animals in from the surrounding seabed, then the traps look good while the wider stock is exactly as thin as before.
The second case is the dangerous one, because a concentrated fishery reads as a healthy fishery right up until it does not.
Nobody has settled it yet, and the honest position is that the sampling is still running and the paper is not written.
What is certain is that the crabs are there, and that somebody is out on a lobster boat every other week finding out why.
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