WGHARP 2019.pdf (6.77 MB)
ICES/NAFO/NAMMCO Working group on harp and HOoded Seals (WGHARP)
Version 2 2022-07-21, 08:23
Version 1 2022-01-18, 14:47
reportposted on 2019-01-01, 00:00 authored by ICESICES
The main objective of the working group was to review recent surveys of Greenland Sea harpand hooded seals and examined harvest scenarios for these populations as well as harp seals inthe White Sea. No new model developments were undertaken for this meeting owing to changesin personnel and illness. No new survey to estimate pup production of Barents Sea/white Seaharp seals was completed.The 2018 aerial surveys resulted in Greenland Sea harp and hooded seal pup production estimatesof 54 181 (95% CI: 36 078–72 284) and 12 977 (95% CI: 9404–16 550) animals respectively.The harp seal estimate was significantly lower than the previous survey, while no significantchange in estimated pup abundance was observed for hooded seals. Models incorporating catchand reproductive rate data were fitted to the time-series of pup production estimates to obtainan estimate of total population size.For the Greenland and White Sea harp seal populations, there is considerable variability anduncertainty associated with the time-series of pup production estimates and reproductive ratedata, and there are very poor fits of the models to the underlying data. The WG recommendsthat some of the input data be re-examined for possible bias and that alternative model formulationsbe tested to improve the models. For the Greenland Sea harp seals, highly variable pupproduction estimates are obtained from a series of mark-recapture studies conducted in the1990s. The WG recommends that these data be re-examined to attempt to understand why estimatesare so variable. For the White Sea harp seal there appears to have been a major change inecosystem conditions resulting in a sharp decline in pup production, in 2004, and pup productionhas remained low since then. The model is unable to account for this decline. Exploratorywork completed during the meeting suggests that incorporating some ecosystem indices into themodel might improve model fit to the data. This needs to be examined further. The WG concludedthat the models did not provide reliable estimates of population trends, but that estimatesof current population size were robust. Therefore, harvest scenarios for these two stocks wereprovided using the Potential Biological Removal approach based upon estimates of currentabundance from the models.The Greenland Sea hooded seal population has declined and remains below the Lower ReferenceLimit despite no hunting since 2007.
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