Movements, growth rates and strong sexual segregation in critically endangered tope sharks <i>Galeorhinus galeus</i> in the Northeast Atlantic
Bibliographic record
Abstract
The tope (Galeorhinus galeus, Linnaeus, 1758) is a critically endangered shark, which, like numerous elasmobranchs, faces severe global decline. There are, however, substantial disparities between this species' global conservation status and those of some local populations, with the Northeast Atlantic representing a relative stronghold for this species. However, several areas of uncertainty, particularly regarding individual movement patterns, currently hamper region-specific conservation efforts. Therefore, utilising capture-mark-recapture tagging data, collected predominantly by recreational anglers in Ireland - but with recaptures throughout the Northeast Atlantic and Mediterranean - we investigated regional population structure, spatial segregation and individual movement patterns, and estimated sex-specific individual growth rates. This revealed a marked pattern of sexual segregation, with females residing further south than males overall, and with an Irish-specific trend towards male-dominated catches in Atlantic regions versus more even sex ratios in the Irish and Celtic Seas. Recapture timings and locations suggest that female movements are more strongly driven by seasonal water temperatures changes, being broadly in line with the north-south migratory paradigm. Spatiotemporal overlap of mature individuals suggests that the North Channel, Irish Sea and northern Celtic Sea may constitute a key mating area. Female sharks may utilise southerly regions during gestation, with the presence of young-of-the-year indicating that the Irish Sea and neighbouring regions subsequently act as parturition/nursery areas. Our results demonstrate the value of such long-term programmes, in this case facilitated by citizen science, in identifying broad-scale movement patterns in wide-ranging species and specific regions of interest for further study and/or implementation of targeted conservation measures.
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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.001 | 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".