| Autor: |
Anderson, Brooke N., Bowlby, Heather D., Saul, Steven, Kang, Yun, Hammerschlag, Neil, Natanson, Lisa J., Sulikowski, James A. |
| Zdroj: |
Marine & Freshwater Research; 2024, Vol. 75 Issue 12, p1-16, 16p |
| Abstrakt: |
Context: For threatened marine species, data on their vertical habitat use patterns can reveal risk of interactions with fishing gear and can inform bycatch avoidance strategies. Such data are lacking for young porbeagles (Lamna nasus), which are captured as bycatch in north-western Atlantic fisheries. Aims: We aimed to examine temporal patterns in diving and characterise vertical habitat use of young porbeagles during summer and autumn. Methods: We used data from short-term (28-day), high-resolution (5-min interval) pop-off satellite tags attached to 14 young (young-of-the-year and 1-year-old) porbeagles to model depth use. Key results: Occupied depths ranged from the sea surface to 679 m, with ambient water temperatures of −0.2 to 26°C. Diel period and season were factors related to depth use. Conclusions: Sharks exhibited a diel activity pattern characterised by more extensive use of the water column during the day while remaining primarily at the surface at night. Depth use differed between seasons, with summer characterised by greater affinity for surface waters (0–10 m) compared to autumn. Implications: Young porbeagles are at risk of interaction with active fisheries on the continental shelf, but interactions may be reduced by setting gear deeper at night or during summer. The depth use of young porbeagles was investigated for the first time during the summer and autumn in the north-western Atlantic. Depth use varied on both daily and seasonal scales, with sharks occupying surface waters during the night and summer, and diving deeper during the day and autumn. Results can inform bycatch reduction strategies for this vulnerable life stage. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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