Flexible paddle sheds new light on speed: a novel method for the remote measurement of swim speed in aquatic animals

Speed is a key determinant of energy expenditure in free-living animals, and particu- larly in marine vertebrates, where power requirements for swimming increase as a cubed function of the speed. However, current devices used to measure swim speed in free-living animals have limita- tions, including excessive drag, low resolution, high stall speed (ca. 0.3 m s -1 ), cost, biofouling and susceptibility to damage. We present a speed sensor system that utilises the reflectance of infrared light against a flexible paddle that bends in relation to the flow of water over the study animal. In lab- oratory trials, this performed well across a range of speeds (0.1 to 1.75 m s -1 ), and had a stall speed of 0.1 m s -1 . The advantages of this present paddle system are that it is impervious to the presence of matter in the water column, is inexpensive and easily replaceable. Furthermore, the system is able to record speed data at an unparalleled resolution, limited solely by sampling frequency. Data from deployments of devices on free-living imperial cormorants Phalacrocorax atriceps identified changes in speed within and between swim strokes, and also showed that greater speed was generated per kick as the buoyancy decreased with depth. As such, the flexible paddle system holds promise for the measurement of speed in free-living, aquatic animals.

[1]  G. Peters,et al.  Long-term attachment of transmitting and recording devices to penguins and other seabirds , 1997 .

[2]  Using speed-sensing transmitters to construct a bioenergetics model for subadult lemon sharks, Negaprion brevirostris (Poey), in the field , 1998 .

[3]  C. Bost,et al.  Diel dive depth in penguins in relation to diel vertical migration of prey: whose dinner by candlelight? , 1993 .

[4]  P. Yorio,et al.  Dive depth and plumage air in wettable birds: the extraordinary case of the imperial cormorant , 2007 .

[5]  Yves Handrich,et al.  Stroke frequency, but not swimming speed, is related to body size in free-ranging seabirds, pinnipeds and cetaceans , 2006, Proceedings of the Royal Society B: Biological Sciences.

[6]  B. Culik,et al.  Pygoscelid penguins in a swim canal , 1991, Polar Biology.

[7]  Rory P. Wilson,et al.  Trends and perspectives in animal‐attached remote sensing , 2005 .

[8]  S. B. Blackwell,et al.  Onboard acoustic recording from diving northern elephant seals. , 1996, The Journal of the Acoustical Society of America.

[9]  Y. Ropert‐Coudert,et al.  Swim speeds of free-ranging great cormorants , 2006 .

[10]  S. Eckert,et al.  Swim speed and movement patterns of gravid leatherback sea turtles (Dermochelys coriacea) at St Croix, US Virgin Islands. , 2002, The Journal of experimental biology.

[11]  Klaus Lucke,et al.  Antennae on transmitters on penguins: balancing energy budgets on the high wire , 2004, Journal of Experimental Biology.

[12]  Daniel P. Costa,et al.  Swim speed in a female northern elephant seal: metabolic and foraging implications , 1992 .

[13]  T. Williams,et al.  Division of Comparative Physiology and Biochemistry , Society for Integrative and Comparative Biology Swimming Performance and Hydrodynamic Characteristics of Harbor Seals Phoca vitulina , 2016 .

[14]  Rory P. Wilson,et al.  Moving towards acceleration for estimates of activity-specific metabolic rate in free-living animals: the case of the cormorant. , 2006, The Journal of animal ecology.

[15]  Wilson,et al.  UNDERWATER SWIMMING AT LOW ENERGETIC COST BY PYGOSCELID PENGUINS , 1994, The Journal of experimental biology.

[16]  R. Wilson,et al.  A distance meter for large swimming marine animals , 1985 .

[17]  G. Hays,et al.  Continuous plankton records stand the test of time: evaluation of flow rates, clogging and the continuity of the CPR time-series , 2002 .

[18]  D. Crocker,et al.  Swimming speed and foraging strategies of New Zealand sea lions (Phocarctos hookeri) , 2001 .

[19]  Rory P. Wilson,et al.  DETERMINATION OF MOVEMENTS OF AFRICAN PENGUINS SPHENISCUS DEMERSUS USING A COMPASS SYSTEM: DEAD RECKONING MAY BE AN ALTERNATIVE TO TELEMETRY , 1991 .

[20]  Yasuhiko Naito,et al.  Factors affecting stroking patterns and body angle in diving Weddell seals under natural conditions , 2003, Journal of Experimental Biology.

[21]  Optical properties of the sea , 1970 .

[22]  Rory P. Wilson,et al.  Monitoring Penguins at Sea using Data Loggers , 1992 .

[23]  Rory P. Wilson,et al.  Prying into the intimate details of animal lives: use of a daily diary on animals , 2008 .

[24]  J R Zaneveld,et al.  Absorption and attenuation of visible and near-infrared light in water: dependence on temperature and salinity. , 1997, Applied optics.

[25]  I. Boyd,et al.  Swimming speed and allocation of time during the dive cycle in Antarctic fur seals , 1995, Animal Behaviour.

[26]  J. Hassrick,et al.  Swimming speed and foraging strategies of northern elephant seals , 2007 .

[27]  Horst Bornemann,et al.  All at sea with animal tracks; methodological and analytical solutions for the resolution of movement , 2007 .

[28]  Rory P. Wilson,et al.  Surface pauses in relation to dive duration in imperial cormorants; how much time for a breather? , 2004, Journal of Experimental Biology.

[29]  Yasuhiko Naito,et al.  Feeding strategies of free-ranging Adélie penguins Pygoscelis adeliae analysed by multiple data recording , 2001, Polar Biology.

[30]  S. D. Feldkamp,et al.  Swimming in the California sea lion: morphometrics, drag and energetics. , 1987, The Journal of experimental biology.

[31]  Wilson,et al.  HYDRODYNAMIC ASPECTS OF DESIGN AND ATTACHMENT OF A BACK-MOUNTED DEVICE IN PENGUINS , 1994, The Journal of experimental biology.

[32]  Yasuhiko Naito,et al.  Stroke and glide of wing–propelled divers: deep diving seabirds adjust surge frequency to buoyancy change with depth , 2003, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[33]  Yan Ropert-Coudert,et al.  Rush and grab strategies in foraging marine endotherms: the case for haste in penguins , 2002, Animal Behaviour.

[34]  W. Nachtigall,et al.  A Simple Method to Determine Drag Coefficients in Aquatic Animals , 1980 .

[35]  Roger L. Gentry,et al.  Swimming velocities in otariids , 1990 .

[36]  David C. Duffy,et al.  Recording Devices on Free‐Ranging Marine Animals: Does Measurement Affect Foraging Performance? , 1986 .