Applicability of different pot escape gaps to reduce bycatch of undersized snow crab (Chionoecetes opilio) based on laboratory observations

Authors
Cerbule, K., Araya-Schmidt, T., Larsen, R.B., Winger, P.D., Bayse, S.M., Høgmo Karlsen, I., Mossige, M.J., Tendal, N.K., Aak, I.
Year
Journal/Publisher Name
Fisheries Research
Volume (Issue #)
298
Page #s
107753
Contact information
Roger B. Larsen: roger.larsen@uit.no
Summary

Understanding the behavior of snow crab in response to escape gaps is important as it may impact escape success, including the number of attempts, as well as time taken to escape successfully. The study filmed movements of snow crabs through different sized and shaped escape gaps in a laboratory setting and compared movement patterns with those of pot netting mesh. The results showed that escape success strongly depends on crab orientation, the time required to escape a trap can be reduced when using escape gaps, and escape gap design strongly influences size selectivity. In addition, escape probability decreases with crab size. Specifically, circular gaps can retain target-sized crabs while releasing undersized crabs, while elongated or wide gaps increase the risk that target-sized crabs escape. Additionally, side-by-side gaps r mesh can cause limb entanglement and delayed escape.

 

Field Studies

Applicability of different pot escape gaps to reduce bycatch of undersized snow crab (Chionoecetes opilio) based on laboratory observations

Study Type
Study in the lab
Location
Laboratory
Target catch
Snow crab (Chionoecetes opilio)
Effect on bycatch species
Circular escape gaps can retain target-sized crabs while releasing undersized individuals
Effect on target catch
Circular escape gaps can retain target-sized crabs while releasing undersized individuals
Reduction technique
Fishing Gear