Three‐dimensional swimming behavior and activity of a mesopelagic fish. Issue 12 (22nd September 2022)

• Record Type: Journal Article
• Authors: Christiansen, Svenja; Langangen, Øystein; Titelman, Josefin; Vøllestad, Leif Asbjørn; Kaartvedt, Stein
• Is Part Of: Limnology and oceanography. Volume 67:Issue 12(2022)
• Page Start: 2677
• Page End: 2690
• Publication Date: 2022-09-22
• Subjects: Limnology -- Periodicals; Oceanography -- Periodicals; Océanographie; Limnologie; Limnology; Oceanography; Computer network resources; Périodique électronique (Descripteur de forme); Ressource Internet (Descripteur de forme); Periodicals; 551.4805
• DOI: 10.1002/lno.12230
• Languages: English
• ISSNs: 0024-3590

Abstract

Abstract: Knowledge of the three‐dimensional behavior and activity patterns of mesopelagic fishes is crucial for understanding their role in ecological and biogeochemical processes in the ocean. We here show that the use of submerged stationary echosounders enables detailed analysis of three‐dimensional swimming behavior of small mesopelagic fishes in situ. We explore a 4‐month continuous dataset containing more than 100, 000 nocturnal tracks of juvenile Maurolicus muelleri, obtained from a surface‐facing, moored echosounder in a Norwegian fjord. We extend previous observations of vertical nocturnal swimming and step‐wise (stop‐and‐go) dusk and dawn migrations with the corresponding horizontal and turning behavior. In the middle of the night, the M. muelleri mainly drifted with the currents. Horizontal swimming speeds were then usually below 0.5 body length s −1 but increased substantially during the step‐wise dusk and dawn vertical migration. Most vertical relocations were followed by a change in horizontal direction. Our observations are in line with hypotheses of growth maximization in the juvenile fish, and of reducing detection and encounters with predators.