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.