Meeting Abstract

P2.73  Monday, Jan. 5  Escape responses early in life: are young of the year spiny dogfish doing well? MAIA, A.; Univ. of Rhode Island, Kigston amaia@mail.uri.edu

Most species encounter greater predatory pressure early in life, before they are able to achieve adulthood. To evade predators, the most common behavior an animal will use is an escape response. In this study, escape behavior is investigated in young of the year spiny dogfish, Squalus acanthias. Escape responses were elicited by gentle nudging of the tail region to represent a possible predatory event in seven individuals. The results obtained were compared with published data on adult spiny dogfish escape responses. Similar to adult spiny dogfish, the young of the year were shown to elicit C-type escape responses, characterized by a bend into a C shape in stage 1, followed by a return to a natural position in stage 2. Duration, center of mass speed, snout speed, turning rate, and turning angle were quantified for stages 1 and 2. Young of the year spiny dogfish do not show a bimodal distribution in response type, unlike that reported for spiny dogfish adults where two types of response were found, slow and fast. Size corrected maximum velocity of the escape response is faster in the young of the year dogfish, with absolute values close to the values reported at the lower end of the spectrum of adult dogfish. Mean angular velocities in young of the year dogfish are similar to the faster values reported for adults, and maximum angular velocity was faster than in adults. This is consistent with previous reports on greater maneuverability in smaller sized fish. In addition, angular velocity and stage 1 duration are inversely correlated and can be described by a linear regression. Plots of turning rate over time in young of the year dogfish are very similar to the faster escape responses reported for adults. Overall, young of the year spiny dogfish are competent in fast starts and do so in a similar fashion as the adults.