Sportsmen hoping to bag a big moose are seeing increased competition from a tiny parasite that’s cutting down moose populations in New England and across parts of the northern United States, prompting some states to offer hunters fewer permits or halt hunting altogether.

Maine, New Hampshire and Vermont are all issuing fewer moose hunting permits this year, citing the impact of winter ticks on their moose populations. In Minnesota, where ticks are among several factors that have cut the population by more than half in less than a decade, there will be no moose hunting season at all.

Thousands of ticks are sometimes found on a single moose, and the parasites can bleed the animals and cause anemia and death.

“It’s really that they bleed them dry,” said Lee Kantar, Maine’s moose biologist. “If you have 10,000 ticks on you, that surface area makes it so you are removing more blood from that particular animal.”

The largest wild animal in the northeast, moose can tip the scales at more than 1,000 pounds and are prized for their meat as well as their enormous antlers. Maine’s moose season kicks off Monday but the state is coming off a peak year for winter ticks, which have helped reduce the moose herd from 76,000 in 2012 to between 65,000 and 70,000, state officials said.

Maine reduced its number of moose permits from 4,110 in 2013 to 3,095 this year for a season in which more than 50,000 people – a typical number – applied for a permit. New Hampshire officials issued 124 permits – less than half the 275 awarded in recent years – for the state’s October season in the face of a decline in moose population from 7,600 in 1996 to about 4,400 now.

In Vermont, the moose population is estimated around 2,500, below the state’s ideal range of 3,000 to 5,000. The state’s moose herd topped out in 2008, when the state issued 1,255 hunting permits. This year it has issued 285, 70 fewer than a year ago, for its October hunt.

Minnesota’s moose population – which also suffers from predators and disease – has plummeted from 8,840 in 2006 to 2,760, according to state data. The state suspended hunting last year and is in the midst of a multi-year research initiative into possible methods to slow the decline. The northern New England states are keeping a similarly close eye on the health of the moose population.

The ticks occur in all North American moose populations except Newfoundland, Prince Edward Island, Alaska and far northern Canada, said Alberta-based biologist Bill Samuel, who added that the ticks are the “most important external pest of moose in North America.”

Many biologists tie the surge in tick-related moose deaths at least in part to warmer temperatures. Warm fall temperatures and early spring snowmelt improves conditions for winter ticks to thrive, biologists say. Samuel said more ticks survive to lay eggs when the early spring temperature is warm and the ground snow-free.

David Trahan, executive director of the Sportsman’s Alliance of Maine, said he supports the state’s efforts to reduce moose hunting permits to keep the herd healthy. The animal also plays a role in eco-tourism by non-hunters in many states, he said.

“The overall health and sustainability of the moose is what’s most important, for those of us who want to see moose and those of us who want to hunt them,” Trahan said.