Movement patterns of Chilean flounder (Paralichthys adspersus) inside Tongoy Bay (central northern Chile): Observations using passive acoustic telemetry

Abstract

The movement patterns of juvenile and adult Chilean flounder (P. adpersus) were investigated inside Tongoy Bay using ultrasound signal acoustic receivers from June 2012 to March, 2013. Flounder landings in Tongoy Bay and Puerto Aldea from December 2011 to March 2013 were examined. Multiple regression analysis indicated that the Catch per Unit of Effort of Chilean flounder was significantly and negatively related to temperature and depth. Analyses of site- and time-specific length-frequency distributions indicated movement of Chilean flounder on the time scale of weeks, which was likely due to emigration of fish >30 cm in total length. A mark-recapture study was performed. Visible elastomer paint was used to tag 7,510 Chilean flounder. A total of 12 Chilean flounder individuals of different lengths were tagged with an ultrasound transmission device to monitor their movement inside Tongoy Bay. Adults flounder showed increased activity inside Tongoy Bay during the study period, likely due of the differences in length among the released individuals. Although differences were detected in the area occupied by juvenile and adult flounders in Tongoy Bay, it was also noticed that the smaller sized individuals exhibited changes in behavior after implanting the transmitters that resulted in impaired capacity to move freely. Key words: Chilean flounder, acoustic telemetry, movement patters, landing, mark-recapture.