Residence and movement patterns of the marbled flounder Pseudopleuronectes yokohamae around a spawning ground in southern Suo Nada, Seto Inland Sea, Japan

摘要

The residence and movement patterns of the marbled flounder Pseudopleuronectes yokohamae were investigated around a spawning ground located off the coast of Nagasaki point, southern Suo Nada, Seto Inland Sea, Japan. Twenty marbled flounder (9 females and 11 males) tagged with ultrasonic transmitters were released on November 29, 2017, before the peak spawning season (peak spawning season: mid–late December), and their distributions were recorded by 15 acoustic receivers until January 21, 2018. Eighteen fish roamed around in the study site or disappeared from the study site but appeared again. The 18 fish then emigrated from the study site by mid-December. The remaining two (1 female and 1 male) of the 20 tagged fish resided until mid-January and continuously roamed around areas of silt–clay to very coarse sand bottom sediments both day and night during the peak spawning season. Movement patterns of marbled flounder may be related to spawning site selection or reproductive behaviors. The fish that emigrated may have roamed around the study site or surrounding areas in order to judge whether to spawn there, but most of them may not have in the study site. In contrast, the remaining two fish may have reproduced within the study site.