Science Advisory Report 2012/076
Harvest advice for Nunavik beluga (Delphinapterus leucas)
Summary
- Nunavik hunters harvest beluga from a mix of discrete stocks designated after their specific summering areas: Western Hudson Bay (WHB), Eastern Hudson Bay (EHB), and Ungava Bay (UB). Genetic analyses have shown that the proportion of EHB beluga in the harvest varies spatially and seasonally.
- The 2012 reported harvest consisted of 13 beluga taken in eastern Hudson Bay, 12 in Ungava Bay, 208 in Hudson Strait in the spring and 56 in the fall, 61 near Sanikiluaq (Nunavut), and 11 in the Long Island/James Bay area.
- Systematic aerial line-transect surveys to estimate abundance of beluga whales were conducted in James Bay and eastern Hudson Bay from 19 July to 18 August 2011. Unlike in previous years, the high coverage stratum in the eastern Hudson Bay was only surveyed once because of unfavourable weather conditions.
- Ungava Bay could not be surveyed in 2011 because of weather conditions. Previous assessments indicate that any harvest from the UB stock poses a threat to its recovery.
- The surface estimate for James Bay was 7,154. The abundance estimate for James Bay, after correcting for submerged beluga, was 14,967 (CV 29.9%).
- The surface abundance index for EHB was 1,434. Correcting for submerged animals and adding a count of 354 whales in the Little Whale River estuary resulted in an abundance estimate of 3,351 beluga whales (CV 48.9%) in eastern Hudson Bay.
- The 2011 abundance estimate was used to update a population model that also integrates catch data and proportions from genetic analyses. Model results suggest that the EHB stock has declined from ~4,000 whales in 1985 to ~3,000 in 2001, then has increased slightly to ~3,200 beluga in 2012.
- According to the model, removing 62 EHB animals in future harvests has a 50% probability of causing a decline in the stock, while lower harvests would likely allow some recovery. The 2012 harvest was equivalent to 59 EHB beluga.
- The EHB stock is straddling the limits of Nunavut and Nunavik. In 2012, the harvest by Sanikiluaq was 80% higher than in the previous 5 years. Although harvesting by Sanikiluaq hunters is currently closed in summer to limit the number of EHB beluga taken, changes in their harvesting practices could have an important impact on the EHB stock.
- Developing a precautionary framework would facilitate sustainable management and recovery of the EHB stock. The Precautionary Reference Level is defined as 70% of the inferred maximum stock size, which was estimated at 8,000–11,600 beluga. To encompass this range, proposed recovery targets are T1=5,600 and T2=8,000.
- Long-term projections indicate that none of the harvest scenarios can yield an 80% probability of reaching the T1 target over a 50 year timeframe. A scenario with no harvest has a 58% probability of reaching T1 in 25 years and a 35% probability of reaching T2.
- Alternative recovery targets could be based on the minimum stock size required to yield an acceptable sustainable harvest defined by resource-users. The 1985 stock size of 4,000 is not a plausible estimate of maximum stock size and should not be used to propose a recovery target.
- Projections do not include increases of other sources of anthropogenic mortality (e.g., vessel strikes and impacts of noise).
This Science Advisory Report is from the October 29 to November 2, 2012 Annual meeting of the National Marine Mammal Peer Review Committee. Additional publications from this process will be posted as they become available on the Fisheries and Oceans Canada Science Advisory Schedule.
Accessibility Notice
This document is available in PDF format. If the document is not accessible to you, please contact the Secretariat to obtain another appropriate format, such as regular print, large print, Braille or audio version.
- Date modified: