Rapid ecosystem change after the cod collapse in Newfoundland & Labrador
Bibliographic record
Abstract
Abstract The cod collapse of Newfoundland and Labrador in the early 1990s was predicated by collapses of the key forage fish species in the region, capelin, and the wider groundfish community. After these collapses, rapid changes in ecosystem structure and function have been observed. From the early 2000s to mid 2010s, invertebrates dominated ecosystem biomass and the snow crab fishery became important to the region. During the late 2010s, invertebrates declined as groundfish stocks increased, although not to pre collapse levels. We developed two ecosystem models representing 1) the Grand Banks and 2) the Newfoundland and Labrador Shelf ecosystem structure and function for 2018-2020. We compared these models with existing ecosystem models that represent the combined Grand Banks and Newfoundland and Labrador Shelf ecosystem for the pre collapse (1985-1987) and invertebrate dominated (2013-2015) periods. Variability in primary productivity, species biomass, and catch reveal that the two model regions are distinct in ecosystem structure and function. Primary and secondary production has increased in the most recent period, however capelin biomass – an important factor for cod recovery – has remained low. Harp seals play a strong top-down ecosystem role and may be contributing to impaired cod recovery. Since the decline in capelin abundance, Arctic cod became an important alternative prey on the Newfoundland and Labrador Shelf region compared to reliance on sand lance and squid on the Grand Banks. Capelin has not shown signs of recovery in either region. Overall, the ecosystem structure in 2018-2020 in both regions is closer to the pre-collapse state than it was in 2013-2015, and the rapid change indicates that the system is highly dynamic.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
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".