Muskrats’ decline puzzles researchers
(Reprinted from above link)
The trouble with being in the rat race, comedian Lily Tomlin said, is that even if you win you’re still a rat.
Such insults don’t seem to bother the common rat, the rodent version of which is also known as the brown, wharf, street, sewer and Norwegian rat. Rats thrive in American cities.
While Chicago, Los Angeles, New York and Washington lead the nation as havens, Orkin ranks Cleveland at No. 8, Cincinnati at No. 20 and Columbus at No. 25 among the most vermin-infested cities.
Rodent cousins of rats include squirrels, beavers, chipmunks, porcupines, hamsters, mice, voles and other species. Many rodents are doing OK, though none likely as well as the adaptable city rat.
Among the recognizable rodents in apparent decline are muskrats, a North American native and wetland dweller long sought for fur and historically for meat by trappers.
Not as attention-worthy as the dam-building beaver, muskrats nonetheless generated considerable revenue in the fur-trade game. Muskrats persisted in many places even when, as happened in Ohio, beavers were eradicated and other furbearers eliminated or threatened.
When pickings became slim, muskrats became so important to trappers that many marshes with a muskrat presence were saved that otherwise wouldn’t have been, trapper Jeff Traynor recently wrote on the Furbearer Conservation website.
That noted, here’s the contemporary skinny: In 1980, almost 6 million muskrats were taken by trappers in the Midwest. By 2014, the number had dropped to fewer than a million.
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Muskrat populations, wildlife biologists know, fluctuate naturally. Records show, however, that harvest numbers went up and down during the 1980s, then plunged precipitously at the end of the decade and have stayed at a far lower baseline.
Questions arose whether economics might explain the low harvest numbers. Trapping is not easy work, and when fur prices drop too far, many trappers figure the effort might not be worth the payoff.
Also suspected was whether a general decline in the number of trappers could influence the harvest enough to make it drop to about one-third of its previous norm. Neither the general decline nor market swings correlated strongly with the year-to-year ups and downs of the muskrat harvest.
Consequently, wildlife biologists began investigating whether the muskrat population was dwindling because of unknown factors.
Biologist Suzi Prange, then employed by the Ohio Division of Wildlife as a furbearer specialist, indicated in 2016 that pesticides and personal-care products showed up in many of the 592 muskrat carcasses donated for study, although not at levels expected to affect health.
What did show up in 40 of 41 tested animals were high levels of metals, enough to have possible “negative effects on health, survival and reproduction,” Prange concluded. Eighteen metals were found, including antimony, calcium, iron, mercury, molybdenum and strontium.
The source of the metals and their influence on muskrats remain open to speculation. But the shrinking of the muskrat population goes far beyond Ohio, to the Northeast and the entire Great Lakes basin. More research has begun.
Trapping for muskrat and mink, along with trapping and hunting of fox, skunk, opossum, raccoon and weasel, is legal statewide beginning today. Legal trapping for beaver and river otter begins Dec. 26.