Scientific observation program around Kerguelen Island, a ship-of-opportunity for bird and mammal data collection

Fishing activities targeting Patagonian toothfish (Dissostichus eleginoides) are conducted year round on the edge of the Kerguelen plateau. Since the early 2000s, scientific observers on board have been asked to collect data on both seabird and marine mammal abundances using standard protocols. Data collection is constrained in space (fishing activities occur only between 500 and 2 000 m depth) and time (effort declines in winter when quotas are caught and in February due to fishery closure) but represents the most important dataset of observations at sea in this area. Sixteen taxa of marine mammals and 37 taxa of birds were observed during the 2001–2017 period. This study provides the first insights on the spatio–temporal patterns of occurrence of some of these species. It also highlights the potential for data to be collected by fishing vessels targeting Patagonian toothfish used as ships of opportunity to investigate trends and distribution of seabirds and marine mammals in remote and difficult-to-access areas of the Southern Ocean.