August 17, 2023 — Alex Iacono, a lobsterman who says he favors lobsters and ocean solitude over people, is worried about the future of his business. Iacono, who lives in Truro and fishes out of Provincetown on the F/V Storm Elizabeth, says his catch has significantly dwindled in recent years.
He’s not alone; other lobstermen working across Cape Cod Bay have noticed a downward trend. They believe that hypoxia — dangerously low levels of oxygen in the water — is to blame.
On Aug. 11, local lobster fishermen were advised by the Div. of Marine Fisheries (DMF) that low levels of dissolved oxygen had been recorded in two areas: at the southern end of Cape Cod Bay near Barnstable and here, in the waters between Provincetown and Wellfleet.
Hypoxia first came to fishermen’s attention in 2019 when it caused a catastrophic lobster die-off in the bay. After that, the DMF started affixing sensors to buoys and traps to monitor oxygen levels, and they have consistently observed mild hypoxia since then.
Tracy Pugh, leader of the Invertebrate Fisheries Project at DMF, pioneered a “stoplight” color-coded hypoxia mapping system: green indicates areas with over 6 mg. of dissolved oxygen per liter of water; water with under 6 mg/L is coded yellow on the DMF map; orange signals mildly hypoxic water with less than 4 mg/L; and red indicates severely hypoxic water, with less than 2 mg/L of dissolved oxygen.