Declining Sea Duck Populations Prompts Awareness
March 09, 2016
When Captain Jeff Coates started hunting sea ducks on the big water of Chesapeake Bay back in 1991, he was often the only boat around. Times have certainly changed. What was once a sport reserved for thrill-seekers and trophy hunters has turned into its own thriving sub-culture.
"I've had as many as seven other rigs within sight doing the same thing I was doing in recent years. There are more guides hunting them and more boat makers building sea duck boats," says Coates.
He can't say if the increased pressure is having a negative impact on populations of sea ducks, but he certainly wonders. Coates sees far fewer long-tails (oldsquaw) than he did 20 years ago. White-wing scoters are also less abundant. Wintering brant populations are way down where he hunts, as well.
It's not just his imagination. Sea duck populations are indeed sliding, according to the U.S. Fish and Wildlife Service, Environment Canada and various universities. That's why officials with the USFWS are recommending a reduction in season length and bag limits for the Atlantic Flyway starting in 2016. If they go through — and they are expected to — the season would be cut from 107 days to 60 and bag limits from seven birds per day to five. Brant limits were cut to just one bird per day this year.
"What we are concerned about is whether sea duck productivity is enough to offset harvest. I'm not convinced hunting is having an impact, but it's the one thing we can control," says USFWS migratory gamebird biologist Chris Dwyer. "Frankly, we don't know if some species are up or down, but we do know that overall, sea duck populations are on the decline over the last 30 years. They breed in some very remote locations and tend to move around a lot, so they can be difficult to count."
Biologists do know that juvenile-to-adult ratios of common eiders are down in Canada and the U.S. In 1986, Canadian hunters killed about seven juvenile birds for every adult. That plummeted to just two juveniles for every adult in 2013. The ratio is much worse, .31-to-1, for common eiders killed in U.S. waters, an indication of poor duckling survival on the nesting grounds.
Dwyer says eiders, which nest along coastal waters from Massachusetts north to Labrador, suffer high predation, mainly from gulls. No one seems to know why gull predation increased in recent years, but there are a number of theories.
"One is that gull populations did well because of the open dumps near the coast. Many of those closed and gulls were forced to shift their diets to eggs and baby birds. Overfishing could also have something to do with eider declines," says Dwyer. "We don't really know."
Black scoters had similar juvenile-to-adult harvest ratios. Hunters killed just .3 juveniles for every adult in the Atlantic Flyway in 2014. Figures for long-tails aren't much better. Hunters shot .4 juveniles for every adult.
Little is known about either species. Both are reclusive ducks that nest in some of the most remote locations in North America. Their breeding range is vast, making them difficult to count or study. According to a report by the Sea Duck Joint Venture, there is no concrete population data for long-tails in the eastern U.S. No one knows for sure how many there are in North America, either. The same is true for the various scoter species. What is known is that long-tail numbers have fallen significantly since the 1950s.
"I definitely don't see as many where I hunt," says Coates. "I wonder if they are short-stopping on the Great Lakes."
The invasion of non-native zebra mussels in the Great Lakes in the 1990s did provide a new and abundant food source. Hunting pressure is somewhat lighter there than on the Chesapeake, as well. However, Long Point Waterfowl director Dr. Ted Barney doesn't think the increased forage led to any short-stopping. Telemetry studies show the Great Lakes population of wintering long-tails is different than the population that winters on the Chesapeake and the Atlantic Coast.
He notes that two hard winters in a row contributed to declines in long-tails on the Great Lakes. Ice cover prevented the birds from reaching food, so thousands simply starved to death. An outbreak of avian botulism also killed an unknown number of long-tails.
"The wintering Great Lakes long-tail duck population averaged about 53,000 per year between 2002 and 2014, but the mid-winter survey found 30,000 in 2014," says Barney.
But winter-related kills nor disease play a major role in population trends, according to Barney. Other factors are likely at play, but exactly what those are remains to be seen. That's why biologists are ramping up research efforts to figure out what is contributing to the slow, steady decline of long-tails and other sea ducks.
"It could be changes in water temperatures or food resources, increased predation or some factors that we just don't know about yet," says Dwyer. "Pacific sea duck populations are facing similar challenges. There are various research projects underway in the Pacific Flyway, as well."
The Pacific Flyway Council, a consortium of federal and state waterfowl managers, had not yet made any recommended changes to the flyway's sea duck season as of early September. The Pacific Flyway already has a limited and highly-regulated brant season, thanks in part to uncertain population figures. Mid-winter counts are above population objectives, but the number of nests has declined substantially.
"We've had very poor production the past three years and this year is looking like it will be just as bad or worse," says North Carolina biologist Joe Fuller. "Last year the mid-winter survey showed a population of about 111,000. The peak population in recent years was about 180,000 in 2000."
Fuller says at least two factors are contributing to poor brant production: bad weather and competition from snow geese on their nesting grounds (hunting does not appear to be a factor). However, restricting the flyway harvest is one way to ensure more birds return to the nesting grounds this spring.
"Some managers wanted a season closure this year, but it was agreed that if the mid-winter count falls below 100,000, the season will be closed next year," adds Fuller.
Coates isn't sure how that will affect his guide business. Some hunters may not book a trip for a single brant; others may see an impending closure as an incentive to hunt while there is still a season. The same thing might happen with sea duck hunters, although there is no talk of closing the sea duck season.
"The changes are just a pre-emptive measure," says Dwyer. "The sky is not falling."