44 DECEMBER 2022 • WORLD AQUACULTURE • WWW.WA S .ORG in the 70-m range and affix the camera to the robotic arm. The assembly was then brought immediately to teh surface. At this depth, the temperature is still cold and this would avoid subjecting the set to high surface temperature for an unnecessary time. The assembled hyperbaric chamber was attached to the ROV’s arm and quickly brought on board without the support dive team. The set was then reconnected to the fully protected high-pressure systemwith cold water (21 C) inside the thermal box preserving fish’s physiological condition. The decompression process took 30 hr in total, always considering visual observations of the individuals, which on some occasions needed to be recompressed due to excessive buoyancy, especially in the final phase, the last 10 m. The need for recompression suggests the adoption of a specific decompression protocol, which considers longer downtimes during final stages of the process. Finally, fishes were released from the hyperbaric chamber and kept at ambient pressure with water temperature close to original values (21 C), allowing a slight increase of 1 C per day over the three days after release to acclimate fish for transport. Maintenance at base was carried out with daily water exchange for fresh seawater kept under controlled temperature in an acclimatized room. On the third day after release from the hyperbaric chamber, a period when the fish had undergone adaptation to ambient pressure, fish were placed in plastic bags containing seawater with a pure oxygen atmosphere and transported by air in a polystyrene box to Biomarine Ornamental Aquaculture (São Paulo/SP) facilities, and subjected to quarantine upon arrival. Currently, the specimens are healthy, accepting inert shrimp-based food. Despite high costs and needs for improved equipment and procedures, the capture operations proved that it is possible to bring mesophotic fish to the surface with a high degree of safety, submitting them to proper decompression protocols without causing hyperbaric damage. Care to control temperature with specific equipment was as important as pressure control in the hyperbaric system, and it must be always prioritized; after all, mesophotic fish generally inhabit cold waters. At the capture site, temperatures varied from 28 to 30 C on the surface and from 18 to 20 C on the bottom (between 100 and 138 m). Technical improvements are essential to optimize locating and capturing specimens with gear that can provide passive fishing, diversification of specimens captured and improvements in diving procedures. Seeking greater operational efficiency, for future operations, the Biomarine teamwill consider a few changes, such as an increase in the number of bottom divers and fishing training in shallowwaters. Biomarine also intends to incorporate scientists specialized in mesophotic ichthyology who have training experience with rebreather use in deep dives, aiming to expand research contributions for these species and/or environments. Finally, the use of an ROV on deeper dives should allow increased substrate prospecting activities and deletion of locations with a biodiversity that is not in accord with operational objectives. Benefits that knowledge about mesophotic fish can bring to environmental conservation are undeniable. Future results of captive breeding of these species can help to understand several biological mechanisms not yet elucidated by science. Biomarine intends to contribute very actively to the knowledge and conservation of mesophotic regions. Notes Eduardo Gomes Sanches, Bruna Larissa Maganhe and Laura de Oliveira Camilo, Marine Fish Laboratory, Fisheries Institute. Ubatuba/SP, Brazil. Email: eduardo.sanches2005@gmail.com Flavio Félix Bobadilha and Adilson Ramos Santos, Biomarine Ornamental Aquaculture. São Paulo/SP, Brazil. Email: flaviobobadilha@gmail.com 1 Shurflo 9325 043-101 12/24v 2 Coel Z31 12/24v 3 Plastomatic RVDM In-line Pressure Relief Valve, PVC/EPDM Thd, Indelco Plastics Corporation, USA 4 WEG - CWCA0-22-00V26 5 FIFISHV6S, with 200-m cable 6 Coleman 120 Qt Blue nights References Callan, C.K., A.I. Burgess, C.R. Rothe and R. Touse. 2018. Development of improved feeding methods in the culture of yellow tang, Zebrasoma flavescens. Journal of the World Aquaculture Society 49:493-503. DiMaggio, M.A., E.J. Cassiano, K.P. Barden, S.W. Ramee, C.L. Ohs and C.A. Watson. 2017. First record of captive larval culture and metamorphosis of the pacific blue tang, Paracanthurus hepatus. 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