Alaska Fish and Game biologists track moose ratios

Kenai Area Fish and Game biologists (including Jeff Selinger) collar moose last winter in a separate study on causes of calf mortality.  ADF&G credit.

Kenai Area Fish and Game biologists (including Jeff Selinger) collar cow moose last winter in a different research study that tracks 100 females, their reproductive rates and their calf survival in GMU 15A and 15C on the Kenai Peninsula. ADF&G credit.

SEWARD, Alaska -

Heidi Zemach for Seward City News -

Alaska Department of Fish and Game’s fall moose composition counts on the Kenai Peninsula, which produce estimates on calf to cow, and bull to calf ratios, were completed recently. The ratios can help wildlife managers like Jeff Selinger, Fish and Game’s area biologist understand, and then educate local fish and game advisory boards on changes in a given moose population. They also help the department to recommend changes in hunting regulations to the advisory councils and State Board of Game.

The moose who inhabit this region are considered one of its most valuable natural resources, according to Fish and Game. They are particularly cherished as a wild food source, and are recognized icons of the region, so keeping track of their populations, and trying to managing them well is important.

That’s hard to do as Kenai Peninsula moose populations have declined steadily in GMU 7 and in the sub-units of Game Units 15 for variety of different reasons including predation (chiefly bears or wolves), disease, malnutrition, habitat, poaching, and road accidents.

Game Management Unit (GMU) 7 covers the eastern third of the Kenai Peninsula, from Hope south to Seward. GMU 15 covers much of the peninsula’s western two thirds, and is divided into subunits A, B and C.

A comprehensive moose population census has never been conducted in GMU 7 due to the region’s mountainous terrain and dense forests which make them difficult to count by air. But other data and anecdotal reports indicate moose numbers were once strong but have declined over the past 50 years.

Fish and Game Area Biologist Jeff Selinger speaks to the Seward Fish and Game Advisory Council. Heidi Zemach file photo.

Fish and Game Area Biologist Jeff Selinger speaks to the Seward Fish and Game Advisory Council. Heidi Zemach file photo.

In Game Management Unit (GMU) 7, the fall composition count, conducted by flying over certain areas and recording the sex and age of the moose they see, determined the ratio of bulls to cows at 25:100, Selinger said. That’s much higher than 2011, (their last composition count) when the ratio was 12 bulls per 100 cows. The calf to cow ratio in GMU 7 is 16 calves per 100 cows. That’s slightly lower than the composition count in 2011, when the ratio was 18 calves per 100 cows.

On the Kenai Peninsula, bull: cow ratios are generally managed for 20 bulls for every 100 cows, Selinger said. There need to be enough bulls of a certain age available to impregnate the cows in a given area in order to maintain the moose population. Unfortunately, cow moose are only in estrus for a very short period of time, so having too few bulls in a population may also result in the late breeding of some cows, which can result in smaller calves less able to survive the winter.

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The calf to cow ratios, measured over time, help managers determine whether there are adequate numbers of cows in the population to become breeding adults, a concept known as “recruitment,” which is an important indicator of the overall health of the moose population, and helps managers determine sustainable harvest rates.

In Unit 15 A, the ratio of bulls to cows showed a healthy ratio of 29 to 100, and there were 25 calves per 100 cows. In the 2012 composition count, the ratio of bulls to cows was 30 to 100, one bull higher more than the year prior, and the cow to calf ratio stayed the same.

In Unit 15C, the bull to cow ratio was 19 per 100, and the ratio of calves to cows was 26 per 100. In 2012, the composition count ratio was 22 bulls per 100 cows, and the ratio of calves to cows was 25 calves per 100 cows.

In March of 2011, when bull numbers in many parts of the Peninsula declined below the desired ratio, the agency recommended tightening antler restrictions to bulls with antler spreads of at least 50 inches or antlers with four or more brow tines on at least one side. The recommendation was enacted.

In 2013, noting that the bull: cow ratios had improved, the agency recommended, and the game board approved an easing of those restrictions to allow the legal harvest of one bull with a spike on at least one side, and antler spreads of at least 50 inches or antlers with four or more brow tines on at least one side.

Fish and Game area biologists will be analyzing all the various data they have gathered to date in the months ahead, and will be formulating any proposals for the State Game Board’s March 2015 meeting by April of 2014, Selinger said.

It’s still too early in the season to tell how this winter will affect the Kenai Peninsula moose populations, however. Even very late winter snows can be particularly hard on moose because they’ve used up most of their fat reserves, and they start to progressively suffer bone marrow loss, which means they are starving.

As far the dead moose biologists examined the femurs of showing signs of starvation, last winter was about average to moderate, Selinger said. But two winters ago was a very bad year indeed for moose, particularly in the northwest part of the Peninsula, GMU 15A. All of the (dead) calves showed signs of starvation, and many of the adult moose they examined the femurs of, also had some bone marrow loss.

Moose hunting harvests totaled 251 bulls in GMU 7 back in 1963-64. But in recent years, the annual bull harvests have plummeted. Only two moose were harvested this year (2013) and only one was harvested the year before.

Annual road kills have actually greatly outpaced hunting harvests on the entire Kenai in recent years however: 186 moose died on Kenai Peninsula roads July 1st 2012 – June 30th, 2013, compared to 66 harvested legally in 2012.

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