The myofibril suspension (in 0.16M KCI-40 mm Tris-HCI , pH 7.5 or 0.16tit KCI-40 mm Trismaleate, pH 5.8)of blue shark and tiger shark was kept at a fixed temperature in the range of 20-45°C with various concentrations of urea and measured for its Ca-ATPase activity with a lapse of tme. In the presence of urea, myofibrillar Ca-ATPase of blue shark inactivated in two first order reactions with an...

The U.S. Atlantic large coastal shark fishery grew rapidly during the 1980s when commercial landings increased from 135 metric tons (t) in 1979 to a high of 7122 t in 1989 (NMFS, 1993). In 1993, a quota of 2750 t was established; in 1997 this quota was halved to 1375 t in order to rebuild depleted shark stocks. This fishery targets several species of sharks that are valued for fins (exported to...

THIS REPORT concerns a study of the feeding behavior in three species of sharks: Carcharhinus menisorrah Miiller and Henle, the grey shark (Fig. 1), Carcharhinus melanopterus Quoyand Gaimard, the blacktip shark (Fig. 2), both of the family Carcharhinidae; and Triaenodon obesus Riippell, the whitetip shark (Fig. 3), of the family Triakidae. The study was conducted in the lagoon at Eniwetok Atoll...

Ecotourism represents a highly popularised activity which has exhibited global growth in recent years. In the present paper, we examine the distribution, frequency, and economic value of shark-based ecotourism operations worldwide. A total of 376 shark ecotour operations across 83 locations and 8 geographic regions were identified. Here we describe the global and regional scope of the industry;...

BACKGROUND The International Shark Attack File mentions only four unprovoked shark attacks on the coast of West Africa during the period 1828-2004, an area where high concentrations of sharks and 17 species potentially dangerous to man have been observed. To investigate if the frequency of shark attacks could be really low and not just under-reported and whether there are potentially sharks tha...

Long-term fisheries independent gill net surveys conducted in Texas estuaries from 1975 to 2006 were used to develop spatially explicit estuarine habitat use models for 3 coastal shark species: bull shark Carcharhinus leucas, blacktip shark C. limbatus, and bonnethead shark Sphyrna tiburo. Relationships between environmental predictors and shark distribution were investigated using boosted regr...

Dorsal closure (DC) in the Drosophila embryo requires the coordinated interaction of two different functional domains of the epidermal cell layer-the leading edge (LE) and the lateral epidermis. In response to activation of a conserved c-Jun amino-terminal kinase (JNK) signaling module, the dorsal-most layer of cells, which constitute the LE of the stretching epithelial sheet, secrete Dpp, a me...