Tonic immobility in 12 elasmobranchs: Use as an aid in captive husbandry
Publication Type: |
Journal Article |
Year of Publication: |
1994 |
Authors: |
Alan D. Henningsen |
Publication/Journal: |
Zoo Biology |
Publisher: |
A Wiley Company, Inc., Wiley Subscription Services |
Keywords: |
animal hypnosis, ray, shark |
ISBN: |
1098-2361 |
Abstract:
Abstract 10.1002/zoo.1430130406.abs Tonic immobility (TI), also known as animal hypnosis, has been observed in a wide variety of taxa and reported in all vertebrate classes with the exception of Agnatha. To date, TI has been reported in six species of elasmobranchs. Preliminary results are presented here for five species of galeomorph sharks, one species of squalomorph shark, and six species of batoids. Tonic immobility was induced in the leopard shark. Triakis semifasciata; the whitetip reef shark, Triaenodon obesus; the blacktip reef shark, Carcharhinus melanopterus; the Caribbean reef shark, Carcharhinus perezi; the swellshark, Cephaloscyllium ventriosum; the California round ray, Urolophus halleri; the shovelnose guitarfish, Rhinobatos productus; the clearnose skate. Raja eglanteria; the cownose ray, Rhinoptera bonasus; and the southern stingray, Dasyatis americana. The broadnose sevengill shark, Notorynchus cepedianus and the yellow stingray, Urolophus jamaicensis failed to exhibit the tonic immobility response, but only one individual of each species was tested. The average induction time ranged from 16.7 sec in the shovelnose guitarfish to 45.7 sec in the clearnose skate. Average duration times ranged from 34.3 sec in the clearnose skate to 274.0 sec in the Caribbean reef shark. Depending upon the species involved, TI has been used as an aid in a few husbandry and medical procedures in captive elasmobranches at the National Aquarium in Baltimore. These procedures have included gross examination, measuring lengths, tube feeding, and drawing blood via caudal venipuncture. Using tonic immobility during these procedures is beneficial as once induced, the subject’s struggling is minimal and usually requires little restraint. © 1994 Wiley-Liss, Inc.