Do Sharksuckers,Echeneis Naucrates, Induce Jump Behaviour in Blacktip Sharks,Carcharhinus Limbatus?

Theoretical and computational fluid dynamics of an attached remora ( Echeneis naucrates )

“…This is especially apparent when considering that large free-stream velocities (~500 cm/s) create drag slightly less than 10% (N = 0.1) of the force required to dislodge a remora (frictional strength). This is in line with observations of both captive and wild remoras as they are typically removed by impact with the surface of the water or other objects rather than by elevated host swimming speeds, even those proceeding jumps (Aughtry, 1953;Ritter, 2002;Weihs et al, 2007). This is somewhat expected given that remoras depend on their hosts for many important needs including food, protection, and transportation.…”

“…For certain simple swimming gaits such as gliding between bouts of active swimming, this technique can deliver reasonable results (Webb, 1975;Miller et al, 2004); however, for more complex swimming gaits the body motions of the host (swimming kinematics) must be included to deliver accurate drag estimations 4 (Webb, 1975;Fish, 1993;Anderson et al, 2001). With respect to remoras, it has been observed that there is a high degree of attachment site fidelity (Strasburg, 1962), and although it has been noted that remoras may reposition themselves on the host (Ritter, 2002;Silva and Sazima, 2008), they typically cease undulatory motion once attachment is created (Sewell, 1925). Therefore, because remoras naturally glide through the water under the power of their host, treating a remora as a rigid body should provide a reasonable estimate of the drag associated with attachment.…”

“…1A and B) in the Echeneidae family have adapted a unique dorsal suction pad that allows them to attach to various host organisms and marine vessels. The list of hosts includes, but is not limited to, sharks, whales, rays, other pelagic fish, sea turtles, dolphins, divers, buoys, ship hulls, and concrete (Strasburg, 1962;Cressey and Lachner, 1970;O'Toole, 2002;Ritter, 2002;Ritter and Brunnschweiler, 2003;Silva and Sazima, 2003;Williams et al, 2003;Sazima and Grossman, 2006;Weihs et al, 2007). Proposed benefits to remoras include transportation ("hitchhiking"), protection from predators, increased courtship/reproduction potential, enhanced gill ventilation and expanded feeding opportunities (Fertl and Landry, 1999).…”

“…With respect to the benefits of the host organism, certain remora species have been known to feed on parasites attached to the host (Strasburg, 1959;Cressey and Lachner, 1970); however, there are many documented cases of hosts that are either unwilling to serve (Aughtry, 1953;Strasburg, 1962) or attempt to remove remoras by various means (Ritter, 2002;Ritter and Brunnschweiler, 2003;Fish et al, 2006;Weihs et al, 2007)). Despite work that has been done to better understand the attachment strength (Fulcher and Motta, 2006) and physical mechanisms associated with remora attachment (Nadler et al, 2013;, very little has been done to quantify the primary force that remoras must overcome in order to maintain attachment, namely fluid drag.…”

Whalesuckers on spinner dolphins: an underwater view

“…Our assumption was that smaller fish attach to varied places, whereas the larger ones would be mostly on the belly for the reason stated above; (4) are the dolphins able to dislodge the remoras by means of a particular behaviour? Our assumption was that dolphins are able to dislodge remoras from particular, sensitive areas (see Ritter, 2002 for this view for sharks). The purpose of the study is to obtain a general view of the whalesucker -dolphin association, and to gain some insight on what advantages the whalesucker may obtain from its association with the spinner dolphin, as well as the possible disadvantages for the host.…”