Swimming sea cucumbers (Echinodermata: Holothuroidea): a survey, with analysis of swimming behavior in four bathyal species

Abstract

Miller, John E., and David L. Pawson. Swimming Sea Cucumbers (Echinodermata: Holothuroidea): A Survey, with Analysis of Swimming Behavior in Four Bathyal Species. Smithsonian Contributions to the Marine Sciences,xmrribtT 35,18 pages, 4 figures, 1990.—New information on swimming behavior of four species of deep-sea holothurians has been obtained using the research submersibles Johnson-Sea-Link (Harbor Branch Oceanographic Institution) and Pisces V (University of Hawaii, HURL Program). Hansenothuria benti Miller and Pawson and Enypniastes eximia Theel were studied off the Bahama Islands, Paelopatides retifer Fisher off the Hawaiian Islands, and Pelagothuria natatrix Ludwig off the Galapagos Islands. Video recordings were made of swimming behavior, and individuals of all species were collected at the time of observation. Four contrasting life modes are represented: H. benti lives and feeds on the seafloor, but when disturbed it can swim vigorously for several minutes by rapidly flexing the anterior and posterior ends of the body into S curves. Enypniastes eximia swims almost continuously, briefly settling to the seafloor to ingest surface sediments. The bulbous body is propelled upwards by rhythmic pulsation of a webbed anterodorsal veil; stability during swimming is maintained by counteractive flexing of posterolateral veils. Paelopatides retifer lives on or near the seafloor and has been found up to 300 meters above the seafloor. The swimming behavior of this species combines locomotory movements of the two preceding species. An anterior veil pulsates, and the posterior half of the body flexes into S curves. Pelagothuria natatrix is truly pelagic, floating or drifting near the seafloor or high in the water column. Swimming is effected by infrequent and irregular pulsation of an enormous anterior veil. There is no evidence to suggest that P. natatrix descends to feed on the seafloor. Published data on the approximately 25 known species of swimming holothurians are summarized Probable reasons for swimming behavior are discussed Swimming appears to be most useful in predator avoidance, escape from physical hazards, locomotion, seeking out suitable substrata for feeding, and dispersal of juveniles or adults. OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. SERIES COVER DESIGN: Seascape along the Atlantic coast of eastern North America. Library of Congress Cataloging-in-Publication Data Miller, John E. Swimming sea cucumbers (Echinodermata, Holothuroidea) : a survey, with analysis of swimming behavior in four bathyal species / John E. Miller and David L. Pawson p. cm.—(Smithsonian contributions to the marine sciences ; no. 35) Includes bibliographical references. Supt. of Docs, no.: SI 1.41:35 1. Holothurians—Behavior. 2. Holothurians—Locomotion. I. Pawson, David L. (David Leo), 1938-. II. Title. III. Series. QL384.H7M55 1990 89-600398 593.9'6-dc20 CIP