A new acoustic transmitter for monitoring the tailbeat frequency of free-swimming ®shes and sharks is described. The transmitter is externally mounted on the ®sh's caudal peduncle and produces an acoustic pulse with every lateral movement of the tail. Field tests on obligate-swimming juvenile scalloped hammerhead sharks (Sphyrna lewini) show these transmitters accurately telemeter tailbeat de ̄e...

A 5 yr spring and summer survey (July 2000 to May 2004) of the elasmobranch fauna of Glover’s Reef Marine Reserve, Belize, documents the use of this oceanic atoll by at least 12 elasmobranch species, including early life-stages of nurse sharks Ginglymostoma cirratum, Caribbean reef sharks Carcharhinus perezi, lemon sharks Negaprion brevirostris, and southern stingrays Dasyatis americana. Elasmo...

By TLC, GM4 was found to be the major ganglioside in the liver of six shark species examined: Odontaspis taurus, Negaprion brevirostris, Sphyrna lewini, Mustelus griseus, Mustelus manazo, and Prionace glauca. A detailed analysis of the glycosphingolipids (GSLs) in the liver of O. taurus (sand tiger shark) showed that it contained approximately 110 nmol of lipid-bound sialic acid per gram of wet...

The Hawaiian stingray, Dasyatis lata, is a common benthic elasmobranch in nearshore Hawaiian waters. Acoustic telemetry was used to track the movements of seven rays in Kaneohe Bay, Oahu, Hawaii. Rays were tracked continuously over 31–74 h periods. Geographical movements were analyzed to determine space utilization and rate of movement. Rays were found to utilize significantly larger activity s...

There is a growing need to identify shark products in trade, in part due to the recent listing of five commercially important species on the Appendices of the Convention on International Trade in Endangered Species (CITES; porbeagle, Lamna nasus, oceanic whitetip, Carcharhinus longimanus scalloped hammerhead, Sphyrna lewini, smooth hammerhead, S. zygaena and great hammerhead S. mokarran) in add...

Light energy is necessary for vision, but ocular tissues are subject to photodamage, and many vertebrates sequester UV-absorbant pigments in their preretinal ocular tissues, in part to minimize such damage. In this study (21 May–1 July 2001), juvenile scalloped hammerhead sharks, Sphyrna lewini (Griffith and Smith, 1834), were exposed to higher levels of solar radiation than they had previously...