It’s official, Norway is planning to kill many more minke whales this season. The 2006 minke whale quote for Norway was officially set last December, the season started on the 1st April. The quota is much higher than for previous years. Here are some of the reasons as reported in the Orberlin Times:
“Norway‘s Foreign Ministry rejected the protest, saying the minke whales Norway harpoons for food in the North Atlantic are plentiful and well able to withstand the planned catch of 1,052 of the giant marine mammals in 2006…
“We are following procedures to ensure that whaling is within safe quotas,” he said, adding that Norway‘s catches were based upon guidelines laid down by the scientific committee of the IWC.
The 2006 hunt represents about one percent of a stock Norway estimates at 107,000 minke whales in its hunting areas in the North Atlantic. Minkes are relatively plentiful, unlike endangered blue whales.
Norway, in a move hailed by whalers but blasted by environmentalists, is also expanding hunts into international waters in the North Atlantic from its own zone for the first time since the 1980s.
It has long said whale stocks have grown uncontrollably since the 1986 moratorium and says the whales, which eat fish such as cod, are partly to blame for falling fish stocks.”
Peter Corkeron made the following comments about the Norwegian minke whale quote in a blog post at this site on 25th January:
“Minke quotas have trended upwards over time – the 2006 quota is 1052 animals. Some of this has come from carrying over untaken quotas from previous years – not a part of the Revised Management Plan/Revised Management Scheme as far as I’m aware. Some has come from changing the “tuning level” – a multiplier built into the CLA/RMP to allow for uncertainty, and changing circumstances. Other problems with quota setting include that predominantly female minkes are taken, and (as I understand it) the CLA assumes a balanced sex ratio in a hunt.
On the science side, one main data requirement is an estimate of abundance with associated estimate of error. The point estimates for northern minke abundance from Norwegian surveys increased, as you note. But the two survey series weren’t directly comparable as they covered somewhat different areas. The most recent survey series was not synoptic – the survey area was divided into 5, with one area surveyed in each of five years. These surveys are logistically difficult to run, and synoptic surveys are really hard to organize – I think the last was in 1995.
So a strong assumption (that is, an assumption that, if it’s wrong, the analysis wrong) is that whales don’t move between survey areas between years. This remains untested.
The actual surveys are vessel-based distance sampling surveys – I’m presuming that you know what distance sampling is (and if this goes to your blog, folks will read up on it).
I’ve never taken part in one of the minke surveys, but know how they work, as I’ve taken part in others elsewhere (US waters, Antarctic). Unlike virtually all other vessel-based surveys for cetaceans, the Norwegian team don’t use binoculars. They have their reasons for this, but it reduces their effective strip width, hence their survey coverage and so the precision of their abundance estimates.
There have been technical queries in past years regarding the Norwegian surveys – double counting (i.e. accidentally recording one whale as two) is an example I recall from the 90s. These have been published as papers in the IWC journal and details can be found there. You have to read through the dry, mathematical language to get at the points being made. There are others who know far more about the machinations within the IWC than I do as I’ve only been to one IWC Scientific Committee meeting.”
While I appreciate that Peter has highlighted potential problems with the Norwegian survey method, I don’t get an appreciation for the extent to which these issues would/should change the overall minke whale quota for 2006.
Rune Frovik disputed some of Peter’s claims in a subsequent blog post, including that:
“The sex ratio is taken into account. Corkeron correctly points out that CLA assumes a balanced sex ratio in the hunt. But the CLA also has a mechanism in case of unbalanced sex ratios. So if the more than 50 percent of the harvested animals are female, this leads to lower quotas. This has been practiced for the Norwegian quota. If the sex ratio was balanced, the current quota could have been higher.”
Following comment from Peter Corkeron this blog post was changed and significantly expanded at 12noon on 25th April 2006.