• The Foveaux Strait oyster fishery (OYU 5) is a high value, nationally important fishery.
• A defining feature of the OYU 5 fishery is the recurrent infection by the parasite Bonamia exitiosa (Bonamia)
• Annual research surveys monitor both oyster abundance within the fishery and the prevalence of Bonamia infection annually.
• A dredge survey was undertaken in February 2024, in collaboration with the Bluff Oyster Management Company Ltd on FV Golden Harvest.
• Oyster densities have declined since 2021.
• In 2024, 1755 oysters were tested from 71 stations, with 18.1% testing positive for Bonamia.
• The prevalence of infection is higher than in 2023 (8.7%) and the highest it has been since at least 2015.
• The increased prevalence of infection is expected to affect the number of recruit-sized oysters in the population.

Scallops (Pecten novaezelandiae) are a species of shellfish that live on the seabed in sandy coastal areas in Aotearoa-New Zealand (NZ). Scallops support highly valued commercial and non-commercial (customary and recreational) fisheries, but fishery closures have been put in place due to sustainability concerns.

Scallop populations in northeastern NZ were surveyed in 2024 to assess the status of the scallop beds since the closures were first put in place in 2022. A variety of camera, dive, and dredge survey methods were used to survey the main scallop fishing areas to collect the images and data for analysis.

The 2024 survey work included the first use of Artificial Intelligence (AI) in a NZ scallop survey. AI was used to automatically find and measure the size of scallops visible in the photos from the camera survey. The AI method was tested using data collected by the divers. The dredge survey allowed a comparison between the camera and dredge survey methods.

The findings of the camera/AI and dredge surveys were similar. The AI correctly identified and measured most of the scallops in the camera survey photos. Future work could further improve this new method.

The 2024 survey results showed there had been some localised increases in scallop numbers in Eastern Coromandel and in Whangarei Harbour, but there was no evidence of recovery elsewhere. Due to the protection from the fishery closures, many scallops have survived and grown to larger sizes. However, the numbers of small (young) scallops were low compared to previous years, except for in Eastern Coromandel and Whangarei Harbour. Further recovery of scallop beds may take some time.

(Manuscript 4569)