TWO SERIES OF MACROZOOPLANKTON CATCHES WITH THE N70V NET IN THE INDIAN SECTOR OF THE ANTARCTIC OCEAN (Ninth Symposium on Polar Biology)

• Main Authors: カワムラ アキト, Akito KAWAMURA
• Format: Report
• Language: English
• Published: Proceeding 1987
• Subjects: Antarctic; Antarctic Ocean; Indian; Rorqual; The Antarctic; Antarc*; Euphausia superba; Polar Biology; Proceedings of the NIPR Symposium on Polar Biology; Copepods
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=5018; http://id.nii.ac.jp/1291/00005018/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=5018&item_no=1&attribute_id=18&file_no=1

Two series of macrozooplankton catches using the Discovery pattern N70V net were studied as a supplement to the previous report by the present author. These samples revealed that both standing crops and individual numbers of three copepod species, Calanus propinquus, Calanoides acutus and Rhincalanus gigas, were extremely poor in comparison with any other comparable data. The results again make us confirm a possible change of major herbivorous copepod populations in the sizes and/or community structures. These changes are perhaps a phenomenon related to gradual changes in quantitative relationships of relative biomass size between Euphausia superba and their predators, especially through the intense exploitation of rorqual whales during the past several decades, which resulted in a 'surplus' in krill population. A possible intensified competition for food between herbivorous copepods and E. superba is discussed as the subject of feeding strategies.