Fishes in the genus Scomber are migratory species specialised for rapid and efficient swimming, and are also of high commercial value. Despite advances in understanding the horizontal distribution and migratory behaviour of Scomber species, knowledge remains limited about their vertical movement patterns. This paper presents a proof of concept showing the potential for using biologging techniques to help understand the vertical movement patterns of a scombrid. The vertical swimming behaviour of 1 chub mackerel S. japonicus was measured at 10 s intervals for 166 consecutive days from November to April with an electronic tag. The tagged fish showed a normal pattern of diel vertical migration (DVM) that involved movement from shallow depths at night to greater depths during the day. However, this pattern of DVM broke down or reversed on a short-term basis during the overall recording period. In addition, the fish modified the depth and amplitude of DVM in response to the vertical gradient of the water temperature. Consequently, even though the tagged individual used a wide range of depths uniformly (0 to 130 m), it remained within potentially physiologically adequate ambient water temperatures in a vertically and seasonally heterogeneous thermal environment.
All Science Journal Classification (ASJC) codes
- Ecology, Evolution, Behavior and Systematics
- Aquatic Science