Salp abundance and size-structure at Chatham Rise, east of New Zealand, measured during the SalpPOOP (TAN1810) campaign onboard the RV Tangaroa

Double oblique zooplankton net tows from 200 m water depth to the sea-surface were carried out using a 0.7 m diameter Bongo frame with paired 200 µm mesh nets, a General Oceanics Flow meter affixed to each net to measure the volume of water filtered, and a temperature-depth recorder. Tows were conducted at least twice daily (day and night), with one additional day per cycle of sampling every 2-3 hours for further studies of diel patterns. A quantitative subset of salp specimens were identified to species using keys (Foxton 1965, doi:10.1017/S0025315400016519; Bone 1998), classified into oozooid or blastozooid stage, and measured for total length and corrected to oral to atrial (OAL). For plots and calculations, Salpa thompsoni lengths were divided into 5 mm bins, and abundance was calculated for each size bin.