Consistent movement traits indicative of innate behavior in neonate sharks
Michelle R. Heupel et al. in Journal of Experimental Marine Biology and Ecology
Michelle R. Heupel, Colin A. Simpfendorfer, Esben M. Olsen and Even Moland
Breaking down animal movements into quantifiable metrics provides an opportunity to define patterns within movement. Here, long-term telemetry data of blacktip sharks (Carcharhinus limbatus) from 1999 to 2002 were used to define movement patterns of neonate individuals. Movement was described by measures of central tendency and dispersion in distance moved, linearity of movement, bearing of movement and activity space size. These metrics were considered to define the movements on which behavior of juvenile blacktip sharks were built. Distance moved, bearing variance and activity space metrics revealed a significant increase among months suggesting longer movement steps and more variable movement over time. Movement patterns were consistent and non significant between years and there was little correlation with length (R2 < 0.06) or sex of individuals. There was no significant effect of fate of the individual (survival, fished or natural mortality) on movement metrics. Results indicated similarity among the movement metrics of individuals and across naive cohorts, indicating innatebehavior. Individuals in all years increased use of space through time suggesting an ontogenetic shift in behavior and habitat use. The results of this study demonstrated that examining movement metrics provides a useful approach to examining behavior in mobile species.