The time series of relative abundance and age structure from the Ross Sea shelf survey provides information about year class strength, variability, and autocorrelation, and hence is an important input into the Ross Sea region toothfish stock assessment. This was the thirteenth survey in the time series and for the first time, the 2024 survey was not completed as planned. Only 12 stations in the core survey area (10 in stratum A, and 2 in stratum B) and McMurdo Sound (the biennially surveyed stratum N), could be completed because freeze up occurred following an anomalously lengthened commercial season. We recommend that future surveys plan to survey the core strata first, to ensure that the age and abundance data can continue to be used in the Ross Sea region stock assessment. Should lengthened commercial seasons continue, then a more fundamental solution may be required for future surveys, and this will be considered when a new multi-year research plan is submitted next year.
A VME trigger occurred on 3 of the 5 line segments at the first station in McMurdo Sound. The vessel notified the CCAMLR Secretariat that it had encountered a VME (initially under CM 22-07 and triggering an automatic closure to future fishing) and ceased research fishing in that location, as specified in CM 22-06 paragraph 9. Relatively little coral or sponge were caught as bycatch on the longline, and little is known about the attraction of Astrotoma agassiz to baited longlines. We recommend that this area and the extent of the VME should be considered for further investigation, such as with underwater cameras, when a new multi-year research plan is submitted next year and encourage study of attraction and movement towards food sources for this species. We further request that Members that may have underwater video or camera footage of the benthic habitat in this area please contact New Zealand. We request WG-EMM to determine whether this area should be protected from future surveys that deploy bottom research fishing gear in 88.1.
Several Important Bird Areas (IBAs) are within the survey area; the 10 nm exclusion area around these IBAs has reduced the amount of surveyable area in McMurdo Sound by 43%. The intention of the exclusion zones appears to be to avoid fishing near areas of breeding colonies, although there have been no known bycatch interactions of penguins, skua, or seals with demersal longlines. We request guidance from WG-SAM, WG-IMAF, and WG-EMM whether the survey continue with the 10 nm exclusion area around IBAs (and thus redefine the strata boundaries and break the time series in McMurdo Sound), or that the survey sample inside the 10 nm exclusion area following Conservation Measures 24-02 and 25-02, but with additional precautionary measures, which may include one or more of the following (1) allow a maximum number of stations to fall within the bird exclusion zone (e.g., 3); (2) restrict stations from occurring within a smaller exclusion zone nearer to the colonies (e.g., the exclusion zone is 5 nm instead of 10), thereby restricting potential disturbance close to the colonies; and (3) set a trigger point for the maximum bycatch allowed before the survey must move out of the 10 nm bird exclusion zones (e.g., 1 bird).