Electronic monitoring in the New Zealand inshore trawl fishery: a pilot study

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Summary

Using on-board observers to monitor protected species (PS) interactions with the New Zealand inshore trawl fleet has a number of inherent difficulties. This study explores the use of Electronic monitoring (EM) as an alternative to observers.

EM systems were deployed on two inshore vessels fishing off the NE coast of New Zealand’s North Island. A total of 14 months, 65 fishing trips, over 260 vessel days at sea and 1022 fishing events were recorded. Overall, sensor data capture success averaged 84% and image recording was complete for 83% of fishing events.

Detailed image analysis was conducted for six protected species monitoring objectives on all usable fishing events recorded, including 60 events where an observer was also on board. Image quality was medium to high for most (98%) of the image data and usability for specific monitoring objectives varied from 0% for warp interactions to 73–97% for the remaining five objectives. EM has tremendous potential for monitoring PS catch occurrences, providing a general index of seabird abundance, and routine monitoring for mitigation practices.

The use of EM for detailed observations of warp strikes or for providing a detailed census of seabirds astern of the vessel would likely be ineffective. The project demonstrated the need to prioritise monitoring objectives to enable better configuration of the EM system. It also highlighted the value of industry involvement in project design and potentially significant cost savings of EM over human observer programmes.

Implementation of EM-based monitoring in New Zealand would require establishment of New Zealand-based infrastructure for improved timeliness, coordination and data quality.