Impacts of angler skill and hook size on catch and welfare outcomes in freshwater recreational pole fishing
Bibliographic record
Abstract
ABSTRACT Objective To enhance the reliability of fishery-dependent data and improve our understanding about possible injuries caused by recreational angling gear from a welfare perspective, an understanding of the social and gear-related determinants of catch rates and injury rates is of critical importance. We experimentally assessed the impact of angler skill and different hook sizes on fish catch, hooking depth, and bleeding status in recreational pole fishing of small-bodied freshwater fish. Methods In fully controlled experimental field studies, we captured close to 2,000 fish and evaluated the effects of angler skill and hook size on catch outcomes and injury (hooking depth and bleeding) in pole fishing for small-bodied freshwater fish (primarily cyprinids). The experiments followed a factorial randomized block design over 3 years (2011, 2020, and 2024) at two water bodies in northeastern Germany. Individual angler skill levels were determined using a set of self-reported angling skill questions administered before experimental sessions started. We examined whether this self-reported skill index predicted actual catch outcomes (i.e., actual skill) while controlling for site and key gear components. Results Anglers self-identifying as skilled indeed achieved significantly greater catch per unit effort (CPUE) than unskilled anglers (a twofold difference on average). Angler skill was unrelated to the size of fish captured. Unskilled anglers caused more fish bleeding than skilled anglers, but the depth of hooking did not vary with the self-reported angling skill index. Hook size (J-hooks ranging in size from 10 to 18) did not influence CPUE or fish injury. Conclusions We found a strong skill effect in experimental pole fishing for freshwater cyprinids. Quantifying and statistically considering self-perceived angler skill in future creel surveys and engaging in CPUE standardization when analyzing time series of observational CPUE data collected from angler populations using a self-reported skill index would improve the accuracy of fish stock assessments that use fishery-dependent data collected from anglers.
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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 | 0.000 | 0.000 |
| 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 | 0.000 |
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".