This report presents the results of the updated trawl footprint in New Zealand waters within the Exclusive Economic Zone in waters open to trawling to a maximum depth of 1600 metres (fishable area).
Results are presented for the 1989–90 to 2021–22 fishing years for deepwater fisheries, and for the 2007–08 to 2021–22 fishing years for inshore fisheries, and combined inshore and deepwater (‘All stocks’) fisheries.
Statistics are presented on the measures of seabed contact for these groupings and include the area in square kilometres of the overall trawl footprints and aggregate (cumulative footprint) areas by year and all years combined. Other measures of contact also presented include the number of tows, the number of cells contacted (a 5 × 5 kilometre grid overlaid on the fishable area), and the number of ‘new’ cells contacted each year that had previously not been contacted.
This study also considered the above measures of contact when including midwater trawl used within five metres of the seabed and within ten metres of the sea bed. Methods were also developed to refine the placement of bottom-contacting trawl effort on underwater topographic features.
Results show that overall measures of contact have decreased in recent years for deepwater, inshore, and All stocks fisheries. Measures of contact increase little when including midwater trawl used within five metres and ten metres of the seabed. The development of methods to refine mapping of trawl effort to underwater topographic features shows promise but would benefit from external validation, perhaps through comparison with data held by the fishing industry.

Escobar-Flores, P.C.; O’Driscoll, R.L.; Ballara, S.L. (2024). Acoustic surveys of Cook Strait and east coast South Island hoki during winter 2023. New Zealand Fisheries Assessment Report 2024/67. 60 p.

Aggregations of spawning hoki were surveyed in Cook Strait and off the east coast South Island (ECSI), in Pegasus Canyon and Conway Trough. The surveys were carried out from 17 July to 30 August 2023 using NIWA’s research vessel Kaharoa.

A calibrated scientific echosounder was used to complete the surveys in each of the trips to the survey areas. Six acoustic surveys, or snapshots, of the main Cook Strait spawning grounds were completed between 17 July and 23 August 2023. Seven snapshots of Pegasus Canyon were completed from 30 July to 29 August and two of Conway Trough on 31 July – 1 August and 13 August 2023

An echosounder looking from 200 metres off the bottom up to the surface was deployed in the outer Pegasus Canyon as an experiment to study the movement of hoki in the area.

We found hoki schools in the main Cook Strait Canyon, in the deepwater southeast of the main Cook Strait Canyon, and in Pegasus Canyon, and Conway Trough.

The average abundance of hoki for Cook Strait in 2023 was 58 000 t. This was lower than the previous survey in 2021 (159 000 t) and the lowest that we have record of for Cook Strait.

The average abundance estimate of hoki for Pegasus Canyon in 2023 was 103 000 t. Although the estimate was only slightly higher than that from the 2021 survey (102 000 t), it is the highest estimate that we have record of for Pegasus Canyon.

The average abundance of hoki for Conway Trough in 2023 was 28 000 t. This was identical to that from the 2021 survey.

Given the increased relative importance of Pegasus Canyon compared to Cook Strait, a recommendation was made for a longer survey period to better cover the spawning events in Pegasus Canyon.