Population Status Tables

Note: this webpage and its sub-pages are DRAFTS with incorrect and incomplete results, and preliminary wording. The pages are currently being used in the Scientific Committee’s website development process to experiment with choices about design and content. Specific whale species/stocks are therefore unnamed, and only three are shown although more will be included later.

Status of Populations - measured by relative abundance and 20-year change

Click here for explanatory information about this table

The IWC Scientific Committee uses computer models to assess the status of whale populations. Status describes what the population abundance is now compared to what it was at a chosen point in the past (e.g., prior to exploitation) and where is it likely to go in the future (e.g., increasing, decreasing, remaining the same). These models combine multiple direct abundance estimates with other information over many years to track population abundance over time (‘trajectories’). Thus, model estimates of abundance for a particular year may differ from the ‘best’ estimate from any individual survey. These modelled assessments represent the Scientific Committee’s best judgment about the status of whale stocks.

The table below summarizes status using two measures from such stock assessments: Relative Abundance and 20-Year Change. Since many whale populations were severely depleted during the period of commercial whaling, the Scientific Committee usually expresses Relative Abundance as a proportion of the estimated number of whales prior to whaling, but sometimes it is expressed as a proportion of the number the habitat is likely able to hold (‘carrying capacity’). With a changing environment, carrying capacity may change, so a reference year is sometimes specified. Usually the pre-exploitation abundance is assumed to have equalled carrying capacity then. Thus, a Relative Abundance value of 0.50 means that models indicate that the whale population is half as numerous now as it was prior to whaling, or as the habitat could now support, depending on the case.

The 20-Year Change assessment is based on model estimates of how much the whale stock size has changed over the last 20 years. Negative values mean that the stock has declined. A value near zero is not necessarily concerning: a population near carrying capacity will remain stable (near zero growth) but its status would be very good.

More details on Relative Abundance and 20-Year Change are given here. Specific details about each status assessment, including recent survey data and key concerns, are available from the indicated Status Assessment links.

Species	Population or Area	Relative Abundance	20-Year Change	Link to Status Assessment
Cetacean 1 The BS and EC populations are large and significantly recovered from the era of commercial whaling. The BS population is growing, and the EC population is growing or stable. The SS and OS populations are concerningly small, but SS may be growing.	Barents Sea (BS)	Moderate	Strongly Increased	pending
Cetacean 2 Cetacean 2 is generally abundant and slowly increasing, with populations in the western area likely fully recovered to pre-whaling levels. Populations in the eastern area not as large but growing more rapidly.	North Atlantic	Good	Increased	here
Cetacean 3 The precipitous decline in recent abundance, mainly due to bycatch from illegal fishing, makes it clear that Cetacean 3 is in immediate danger of extinction, with only about 10 animals remaining.	Gulf of Carpentaria	Very Low	Strongly Decreased	statement