Drivers of decadal-scale temporal change in epibenthic megafaunal assemblages on scallop fishing grounds in the Bay of Fundy
Bibliographic record
Abstract
The Bay of Fundy presents a unique environment with extreme tidal range, strong currents, fresh-water river discharge, and diverse habitats that are also experiencing temperature increase at a faster rate than most of the world ocean. There is extensive commercial fishing, valuable beds of sea scallop (Placopecten magellanicus) being found in several areas, some of which have been fished for over a century. Previously, comparative analyses of data collected in 1967 and 1997 found that the epibenthic assemblage on the Digby scallop ground had become more homogenous over the 30 year interval, while species composition had changed significantly. Attached, fragile, epifaunal taxa declined, whereas scavengers and robust burrowing filter-feeders increased in frequency of occurrence, consistent with the physical impacts of fishing gears as a primary driver. The Digby ground along with the commercial scallop grounds around Grand Manan Island and on Lurcher Shoal were resampled in 2007–08 to determine whether the changes off Digby had continued and if they were also occurring in other parts of the Bay. Significant spatial differences among the three scallop grounds were observed. The leafy bryozoan, Flustra foliacea, which was expanding its local range through time, was the leading contributor to the spatial dissimilarity. Depth and mean tidal current speed were the most important environmental variables influencing species composition. Significantly more taxa were recorded per station in 1997 than in 2007–08, while assemblage compositions were significantly different between the two periods. Decadal-scale declines in the frequencies of occurrence of attached, epibenthic filter-feeders, including the polychaete Filograna implexa, were observed, continuing the trend previously reported and consistent with on-going impacts of bottom-contact fishing gears, despite decades of trawling and dredging. However, other and unknown drivers were also implicated in the observed changes.
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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 | 0.000 | 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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".