Assessing the Effectiveness of Drop Chain Footgear at Reducing Bottom Contact in the Newfoundland and Labrador Shrimp Trawler Fishery
Bibliographic record
Abstract
What a dragWho should read this paper?Anyone with an interest in learning how improvements in fishing technology can help reduce environmental impacts and ensure more sustainable fisheries. Why is it important?Bottom trawling ("dragging") entails towing a trawl (net) along the sea floor.Variations on this method are widely used to catch demersal or semi-pelagic species.The growing demand for certification of fisheries by eco-labels such as the Marine Stewardship Council are a strong indication that consumers are increasingly concerned with the sustainability of fisheries, particularly those that involve trawling.The challenge for the fishing industry in this regard is two-fold: limiting the amount of by-catch (incidental capture and mortality of non-target species) and reducing the impact of the trawl on the seabed.Improvements in one or both will not only lessen impacts on marine resources and the environment, but will also mitigate the potential for economic losses as a result of consumer boycotts and sanctions by regulatory bodies.The work outlined here addresses the pros and cons of a modified trawl system for use in the northern shrimp fishery in waters off Newfoundland and Labrador.The study team investigated an alternative design that would reduce bottom contact by the trawl.The modified trawl was tested first in a flume tank, where substantial reductions in contact with the bottom were observed.The study team then conducted experimental fishing trials and demonstrated that the modified trawl system showed good potential for reduced impact on the marine ecosystem, including reduced disturbance of the bottom, and fewer encounters with snow crab -a fishery that overlaps spatially with shrimp in many areas.Results of this work demonstrate that the modified trawl system yielded comparable amounts of shrimp and by-catch, while at the same time minimizing the likelihood of snow crab mortality when compared to a traditional shrimp trawl.At the present time, the modified trawl system cannot be readily adopted by the fishing industry due to unresolved issues around durability and operational safety.Further work will be required to determine methods to reduce snagging of the modified trawl during deployment and retrieval, as well as potential damage of the trawl while fishing. About the authorsAll of the authors are affiliated with the Centre for Sustainable Aquatic Resources (CSAR), part of the School of Fisheries, located at the Fisheries and Marine Institute, Memorial University.The Centre promotes the sustainable development of aquatic resources through collaborative industrial research and development, technology transfer, and education services to the global fishing industry.Key research themes include 1) fishing gear design and testing, 2) biological resource assessments, 3) fisheries development, 4) fish behaviour, and 5) hydrodynamic testing of marine structures.To learn more, please visit www.mi.mun.ca/csar.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".