An Assessment of Newfoundland and Labrador Snow Crab (Chionoecetes opilio) in 2019
Bibliographic record
Abstract
The status of the Snow Crab (Chionoecetes opilio) resource surrounding Newfoundland and Labrador (NL) in Northwest Atlantic Fisheries Organization (NAFO) Divisions (Divs.) 2HJ3KLNOP4R is assessed using a variety of metrics. Data from multispecies bottom trawl surveys, inshore and offshore trap surveys, harvester logbooks, at-sea observers, the Dockside Monitoring Program (DMP), as well as oceanographic surveys are used to inform trends in biomass, recruitment, production, and mortality over the time series. Snow Crab landings declined to a 25-year low of 26,400 t in 2019, while effort decreased to under 3 million trap hauls, the lowest level in two decades. Overall fishery catch per unit of effort (CPUE) was at a time-series low in 2018, but increased back to near the previous historical low in 2019. Despite modest increases in recent years, the trawl survey exploitable biomass index (EBI) has remained at a low level and the trap survey EBI remains near the time-series low. Overall recruitment into the exploitable biomass has been very low in recent years and is expected to remain low in 2020. Total mortality in exploitable crab had been very high in recent years, but is now estimated to be near time-series’ averages in most Assessment Divisions (AD). In 2019, fishery exploitation rates remained high in ADs 2HJ and 3K, declined in ADs 3LNO and 3L Inshore, and remained at low levels in ADs 3Ps and 4R3Pn. Elements of the proposed Precautionary Approach (PA) Framework presented in this assessment are tentative. Limit Reference Points (LRPs) have been established by a peer-reviewed Science process, but Upper Stock Reference (USR) lines remain under development. In 2020, with status quo landings, most ADs are projected to fall within the cautious zone of the proposed PA Framework; however, AD 3LNO is projected to fall within the healthy zone. Broad-scale climate indices appear favourable for improved recruitment to occur in most major areas of the stock range over the next few years. A sharp decline in male size-at maturity (i.e., terminal molt size) in most ADs in recent years that persisted in some ADs in 2019 could dampen short-term prospects for recruitment into the Snow Crab exploitable biomass.
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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 | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".