How many caribou are there really?
December 2006
The Porcupine Caribou Herd has received a lot of attention over the past few weeks in the papers as well as on the radio.
There are many methods of estimating the size of a caribou herd. Researchers have found that the most accurate method estimating the size of the Porcupine Caribou Herd is by using a method called a photocensus. In this method, a specially equipped plane takes photographs of the herd when they "aggregate," or form large groups after calving.
Aggregation takes place in late June or early July, when the herd forms large groups in reaction to biting insects.
The last photocensus for the Porcupine Caribou Herd was carried out in 2001 by the Alaska Department of Fish and Game and the U.S. Fish and Wildlife Service. This count estimated the herd to consist of 123,000 animals.
A photocensus was scheduled to take place again in 2003, and attempts have been made each year since that time to do a count. Factors such as failure of the herd to aggregate and smoke from forest fires have made photocensuses impossible, but an attempt will be made again during the summer of 2007.
Other methods are also used to estimate herd size. The Alaska Department of Fish and Game conducts a calving survey each spring. In this study, the number of calves born, as well as calf survival, is measured. Calf survival rates can be used to get a rough estimate of herd growth or decline.
Last August, the Alaska Department of Fish and Game estimated the herd has continued to decline and that the herd's size is likely to be between 115,000 to 110,000 caribou. This estimate includes calves.
When we look at the population fluctuations between 1989 when the population peaked at 178,000 and 2001 when the herd size had dropped to 123,000 caribou, all the counts were done in a similar fashion, and all counts included calves.
Some sources have said that the calves were photographed by mistake, thus making the herd look larger than it is. There was no mistake; the calves have always been counted in Porcupine Caribou Herd censuses.
If calves are not included, the herd size would be about 78,000 non-calf caribou.
This is how that estimate was arrived at: Last August, the Alaska Department of Fish and Game estimated the herd's size to be between 115,000 to 110,000 caribou. This estimate assumes that the herd has continued to decline at the rate that was observed between the 1998 and 2001 censuses, which seems reasonable considering the rates of calf production and survival recorded during this time.
It does not mean that over the past five years, the herd has declined from 123,000 caribou to 78,000 caribou. However, the troubled Northwest Territories herds, and the fact that all caribou herds in North America are declining, causes significant concern for the PCMB.
This 78,000 number is an important figure as it now allows managers to compare the Porcupine Caribou Herd to other declining herds like the Cape Bathurst and Bluenose-West Caribou Herds in the Northwest Territories. These herds were of similar size to the Porcupine Caribou Herd, and in a very short period of time have declined to drastically low numbers. The Cape Bathurst has declined to less than 2,000 animals; while at the same time, the Bluenose-West herd has declined to about 18,000 animals.
We should be aware that a dramatic decline might be observed in the Porcupine Caribou Herd in the next census.
At the recent PCMB meeting in November, the Board unanimously passed a resolution that the herd is in immediate need of conservation.
That resolution also contained a commitment to develop and implement a comprehensive Harvest Management Strategy in cooperation with all user groups.
The intent of the strategy is for all groups with an interest in the herd to share their knowledge and then come to agreement on the best ways to manage human use of the herd in the future. When the herd's population is high, the strategy should identify the best ways to take advantage of an abundance of caribou. When the population drops, the strategy should identify protective measures and thresholds for when those measures will be triggered.
The PCMB is currently circulating a Harvest Management Protocol to all eight parties with lawmaking authority in the herd's range. By signing the Protocol, all parties will be making a commitment to the process of developing the strategy.
A Harvest Management Strategy meeting will be arranged with senior representatives and leadership of 22 organizations to work out the details of the strategy. This meeting will take place as early as possible once all the signatories agree to the principles of the overall strategy.
This meeting should result in a Porcupine Caribou Harvest Management Agreement.
The PCMB is working to fast-track this process to ensure the Porcupine Caribou Herd receives all the respect it needs so there will continue to be enough caribou to support our future generations.
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