PORTLAND, Maine –The early arrival of spring may be a relief to the people of Portland, but for scientists, early spring means a rapidly changing ecosystem. According to the National Weather Service, in 2016, the average temperature in Portland was 48.4 degrees Fahrenheit, which was as high as it was in 2012.
The Gulf of Maine Research Institute’s Andrew Pershing and USM’s Karen Wilson observed that the change in Maine’s temperature affected Maine’s lobster, cod and herring populations, which have influenced the Maine market. Both scientists noted the change in Maine’s temperature in 2012 and its effect on life.
The change in temperature affected river herring spawning. Wilson said that, in 2012, at a spawning site, herring were aware of the temperature change because they arrived four weeks early.
According to Pershing, the lobster in 2012 mated a month early. The increase in lobster lowered the market price. Although lobstermen caught a lot of product, they made less money compared to 2011.
Between 2004 and 2013, the Maine cod market also suffered. Pershing said that the temperature increase reduced the cod population before fisheries could adjust their quotas. He added that the fisheries later realized the quotas were set too high.
Warming temperatures may decrease cod food sources such as river herring, especially during spawning. These herring spawn in May and leave between July and October. Wilson reasoned that despite the changing climate, river herring are highly adaptive, but because of droughts the fish can’t get to spawning sites or out to the ocean.
“Last summer we had a drought starting in July that lasted to October. There was not enough water going over the dam,” Wilson said. “People kept reporting that the adults were still in the lake. They stayed in the lake and it wasn’t until October when we had the first rains that the fish started to leave.”
The temperature change may have an impact on river herring travel. Wilson added that warmer temperatures may bring the river herring’s sister species, the blue herring, north. Other southern species may also travel to Maine waters. According to Pershing, Humboldt squid and striped bass are likely arrivals.
“In 2016, we had a year as warm as 2012,” Pershing said. “In many ways, the landing and fisheries played out very similarly to what they did in 2012.”
Pershing explained that, because of what occurred in 2012, markets adapted to the overproduction of lobster. By learning and adapting to Maine’s temperature change, fisheries can avoid over-fishing, high quotas, and economic setbacks.
In Portland on Saturday, April 22nd, an estimated 1,000 people gathered downtown for the March for Science in response to Trump’s cuts to the EPA and National Parks, as well as to show support for scientific research surrounding climate change. Other marches took place around the country.
Transcript of Podcast
Spring coming early may be a relief to most of the people of Portland, Maine, but for scientists, early spring means a rapidly-changing ecosystem. Researchers observed that the change in Maine’s temperature has affected the lobster, cod, and herring populations. Scientists note the change in Maine’s temperature in 2012 and its effect on life.
This is what Andrew Pershing at the Gulf of Maine Research Institute had to say about Maine’s climate.
Pershing: “[I]n 2012, we had temperatures throughout the year where we were 5 degrees Fahrenheit above normal.”
In 2012, lobster reproduced a month early. This increase in lobster lowered the market price. Although lobstermen caught a lot of product, they made less money compared to 2011. USM’s professor Karen Wilson observed a similar event in herring spawning.
Wilson: “In 2012, when it was a really warm, they came in four weeks earlier than usual.”
The Maine cod market also suffered.
Pershing: “Every female was producing fewer babies during a warm year than she would in a cold year. And that fewer young fish were surviving to reach maturity in the warm years than they were in a cold year. That led to a reduction in productivity in the stock. That change was happening so fast that the management system couldn’t keep up.”
The cod population decreased before fisheries could adjust their quotas. The fisheries later realized the quotas were set too high. Additionally, warming temperatures may decrease cod food sources such as river herring, especially during their spawning. These herring reproduce in May and leave between July and October. Wilson reasoned that despite the changing climate, river herring are highly adaptive, but because of droughts the fish can’t get to spawning sites.
Wilson: “If they encounter too little water they might not get passed fish ladders or natural barriers like falls.”
Because of climbing temperatures, river herring can’t get back out to sea.
Wilson: “So, last summer we had a drought starting in July stretching into September and October and it wasn’t until October when we had the first rains that the fish started to leave.”
Wilson added that warmer temperatures may bring the river herring’s sister species, the blue herring, north, but people have already found evidence of southern animals in Maine.
Pershing: “We had people reporting blue crab, which is a species that we think of as part of the Chesapeake Bay. We had people bringing in seahorses, which aren’t normally found this far north. A lot of people talking about squid and finding squid egg cases on the beach. Squid are out normally south of Cape Cod.”
In 2012, the temperature change almost ruined the lobster market, but in 2016, the same high temperatures didn’t affect the business.
Wilson: “In 2016, we had a year as warm as 2012. In many ways, the landing and lobster fishery played out very similarly to what they did in 2012. And yet it was a very happy year on the coast of Maine last year. A lot of that is because the industry has adapted.”
By studying the effects of climate change, researchers are looking for ways to adapt to Maine’s new environment and new market. In the future, fishermen and others will probably catch blue herring or, even, squid!