Stock assessment of Northwest Atlantic harp seals (Pagophilus groenlandicus) in 2024
Bibliographic record
Abstract
The Northwest Atlantic (NWA) harp seal population is hunted throughout its range. Seals are harvested for subsistence purposes in Labrador, Arctic Canada, and Greenland, and a commercial harvest occurs in the Gulf of St. Lawrence and off Newfoundland and Labrador. Stock status and harvest advice are provided using an Integrated Population Model which incorporates the periodic estimates of pup production along with updated data on age composition, age-specific reproductive rates, total removals, and environmental conditions. Pup production was assessed through photographic aerial surveys conducted between March 5-25, 2022. Total pup production was estimated as 614,100 (SE=69,500, CV=11%) (rounded to the nearest hundred). The 2022 pup production estimate is the lowest since 1994. Based on the population model, harp seal abundance increased rapidly from the 1970s through the 1990s, peaking at an estimated abundance of 7.5 million seals (95% Credible Interval, CrI: 6.75-8.42) in 1998. The population declined from 1998-2024 with the exception of a period of relative stability between 2009-2019. The estimated 2024 total abundance is 4.4 million seals (95% CrI: 3.65-5.35). This represents a decline in abundance from 2019 (5.6 million, 95% CrI: 4.78-6.63) at a rate of 4.7% (95% CrI: 2.14-7.45%) per year. Harp seals are managed under the Atlantic Seal Management Strategy (ASMS). Based upon the current population model, the environmental carrying capacity (K) was estimated to be 6.9 million seals (95% CrI: 5.27-8.48), resulting in a Precautionary Reference Point (PRP, N70) of 4.8 million seals and a Limit Reference Point (LRP, N30) of 2.1 million seals. The estimated 2024 total abundance has an 80% probability of being below the PRP and is therefore considered to be in the Cautious Zone. Under the revised ASMS, the sustainable harvest levels that ensure an 80% probability of the population increasing above the PRP (N70) in 1.5 generations (30 y) were estimated for the next five years (2025-2029). The annual Atlantic Canadian sustainable harvest levels which meet this criteria are 253,000, 222,000, and 113,000 seals assuming harvest age compositions of 95%, 90%, and 50% young of the year (YOY), respectively. Based on the estimated 2024 abundance, the annual Potential Biological Removal (PBR) for the NWA population is 121,800 seals. This value includes removals from all sources including reported harvest, struck and lost (killed but not recovered or reported), and bycatch in Canada and Greenland. There is considerable uncertainty in the age structure and level of struck and lost of the subsistence harvest in Greenland. Model results indicate that the Greenland harvest has an important impact on NWA harp seal population dynamics. Our harvest projections assume that ice conditions and environmental variables will remain similar to recently observed conditions. Given predicted changes in the environment, we expect a decline in vital rates which could lead to further population decline and lower sustainable harvest levels.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".