The Portland Press Herald ran an article in late April about a significant influx of warm water entering the Gulf of Maine through the Northeast Channel. Whether you believe in climate change or think it’s a crock, this news should concern you. There are many species that are highly sensitive to ocean temperatures and, unfortunately for lobstermen, those include lobster, herring and right whales.
Scientists from the Bedford Institute of Oceanography, based in Dartmouth, Nova Scotia, were surprised in early April to find “a big rush of warm water going into the Gulf.” They measured the temperature of the deep current entering by way of the Northeast Channel, the deep passage between Brown and Georges Banks. Researchers recorded temperatures of 57oF. at depths ranging from 150 feet to 450 feet, according to the Press Herald article. This is reportedly 11oF. above normal and the highest temperature recorded in 15 years of surveys at this time of year. They also measured temperatures at depths of 600 feet in Georges Basin in December that were 5oF. above normal, the highest reading at that site in 40 years. NERACOOS buoys located in Jordan Basin also measured record warm temperatures in 2017 and thus far in 2018.
Scientists hypothesize that this warm water is due to changes in ocean currents affecting the location of the Gulf stream rather than changes in air temperatures.
It makes me wonder what we might see, not this year, but in the 2019 lobster fishing season.
Such drastic variations in ocean temperatures have far-reaching impacts. As ectotherms, the entire life cycle of the lobster, from growth and molting to mating and spawning, is affected by water temperature. So far that has had a positive impact on our resource, but things are starting to change. And let’s not forget about right whales and herring, both of which appear to be highly sensitive to temperature changes.
The right whale population began to decline in 2010 and the whales appear to be suffering a decline in health. Researchers have observed that the whales are skinnier and have given birth to fewer calves in recent years. The Press Herald article notes the concern of Nick Record from the Bigelow Laboratory for Ocean Sciences that the intrusion of warm water into deep-water basins is specifically harming marine species like right whales and herring because both depend on dense patches of the copepod Calanus finmarchicus, which until recently had been present in large numbers in the deep waters of the eastern Gulf of Maine. “That’s the habitat the whales have abandoned in the last few years, so it may be connected to the changes in the deep water coming into the gulf,” Record stated.
Herring fishermen likely share Record’s concern. Though the herring stock appears to be healthy, the fish have eluded fishermen in the offshore Area 3 fishery over the last few years. Less than half of the annual quota has been harvested during the past two years. Area 3 herring fishermen landed only 32% of their quota in 2017 and 44% in 2016. By contrast, they landed 94% of the quota in 2014 and 74% in 2015.
The effect of warm water on right whales has become all too familiar to lobstermen. The shift in copepod distribution sent right whales away from their traditional grounds near the Bay of Fundy and into the Gulf of St. Lawrence, putting them directly in the path of the expanding and unregulated snow crab fishery. Many whales suffered from vessel strikes and entanglements, resulting in twelve deaths in 2017. The cumulative impact of the decline in right whale population, worsening health, and the recent spike in mortalities — all likely driven by changing ocean temperatures — resulted in three lawsuits this year aimed at expanding right whale protections. The National Marine Fisheries Service (NMFS) is in the processing of reviewing how several fisheries, including the American lobster fishery, affect the status of the right whale population under Section 7 of the Endangered Species Act and the federal Atlantic Large Whale Take Reduction Team has reconvened to prepare for potential new regulations that protect right whales.
NMFS’ review of the effect of the American lobster and other fisheies on the right whale population will result in a “biological opinion” on whether those fisheries put the existence of right whales in jeopardy. Given that whales are currently dying faster than they are reproducing, it is possible that NMFS may determine that any number of human activities — including some aspects of lobster fishing — are implicated. If such a determination is made, NMFS may be obligated by law to establish additional protective measures, some of which could alter current whale protection rules.
It’s not just right whales and herring that share a love of copepods. Recent research out of New Hampshire has shown a correlation between the decline in lobster settlement at a New Hampshire site and a lack of Calanus finmarchicus. Additional studies are being done to explore whether this alarming hypothesis may explain the decline in lobster settlement throughout the Gulf of Maine.
Scientists and fishermen alike have been concerned for some time about the fact that the surface waters of the Gulf of Maine are warming at a faster rate than any other place in the world. Others aren’t convinced that the change is real or permanent. But when you add to the warming surface waters data that the deep water basins of the Gulf of Maine are experiencing influxes of very warm water, as well as the evidence of significant changes in lobster settlement, the right whale population and herring landings, I’d say it’s about time to pay attention.
Whatever you believe about the reasons for the changes in the Gulf of Maine, the data show that it is altering. These changes have been and will continue to affect lobster populations, as well as those tiny zooplankton that are so vital for the other creatures, like lobster, right whales and herring, with which we share the ocean.
As always, stay safe on the water.
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