During the last decade, trappers on Prince Edward Island have been reporting declining catches of muskrat in areas where they used to harvest more, so last September a study was begun to try to determine the cause and just how much of a decline was happening.
The ongoing study was commissioned by the P.E.I. Trappers Association and the provincial Department of Environment, Energy and Forestry and is being done by Garry Gregory, a graduate student at the University of Prince Edward Island.
Gregory, who gave an update on the study to the annual meeting of the trappers association in North River Saturday, said trappers in other areas of Atlantic Canada and the northeastern United States are reporting similar declines.
"This is definitely not unique to P.E.I.," he said, but added that as far as he is aware this province is the only area carrying out a study.
Gregory said the reasons behind the fall in numbers are hard to pinpoint although the decline was first noticed in the 1990s.
"Muskrats are traditionally thought of as having population cycles which can operate in nine- to 10-year cycles and they do fluctuate, however, this appears to be going on longer than a normal population fluctuation would be," he explained.
When the decline was first noticed in the 1990s it happened at the same time as the fur industry crash "so it is difficult to say if the muskrats were not there or there was no incentive to trap them," Gregory said.
"A issue like this is very complex and there are a lot of factors to consider."
He said disease, contamination and predators are being studied.
"Muskrats are preyed on by a lot of things and a lot of the predator population on P.E.I. is growing."
He said that includes foxes, coyotes, raccoons, eagles and basically anything that lives around a marsh will eat a muskrat so there are a lot of things to take into consideration when studying the decline.
It was the trappers who first raised the alarm.
"If you are a trapper working in the same marsh and there are less muskrats you are the first to know," Gregory said.
He said they raised the issue with Randy Dibblee, a biologist with the Department of Environment, Energy and Forestry, and together they recognized there was something going on which is why the study was commissioned.
Gregory said there are no hard and fast numbers on the population of muskrats on the Island so the number of muskrats harvested on P.E.I. gives them an idea how the population is doing.
Last year, approximately 1,700 muskrats were harvested, which was well below the average of 4,000 animals, he explained. The last time trappers harvested the average was in the mid-1990s and after that the numbers started to decline.
"You have to remember also that harvests are not necessarily reflective of the abundance because numbers are influenced by how many trappers there are which are influenced by how much they are getting for the muskrat so if you are not getting paid very much for your muskrats you are not going to trap them," Gregory said.
He said that while the harvest data is helpful in determining the numbers, biologists can't just rely on that and they have to study many different reports from trappers and from people who are out in the field and know what is going on.
Carl Balsor, president of the P.E.I. Trappers Association, said there are approximately 100 trappers on P.E.I. and they come from many walks of life, but for most of them it is a hobby. Depending on where they live they trap muskrat, beaver, coyotes, foxes and raccoons. All of the fur harvested goes to be auctioned.