SUSTAINABLE MANAGEMENT OF THE SHARK RESOURCES OF ATLANTIC OCEAN: SOCIOECONOMIC AND BIOLOGICAL CHARACTERISTICS OF THE FISHERY
CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND TO THE STUDY
Not only are sharks among the ocean’s top predators and vital to the natural balance of marine ecosystems, they are also a valuable recreational species and food source (Scott & Scott, 1988). To help protect these important marine species, the many countries especially the advanced countries has some of the strongest shark management measures worldwide (DFO, 2000). There are a variety of resources related to sharks and their management throughout the Atlantic Ocean. There are several shark species found in the Atlantic ocean.
According to Boyle et al (1998), the blue shark is the most common and commercially valuable of these species, however other species such as the Mako, Greenland, Basking, and Porbeagle sharks, have been assessed for their commercial significance in recent years. The blue shark (Pronace glauca) is a large pelagic species with a long slender body, narrow head, five-gill slits, large eyes, a pointed snout, and long scythe-like pectoral fins. It has an elongated, sickle shaped caudal fin (tail), which enables it to be a powerful and fast swimmer. This species has a characteristic blue colour on the upper surface shading to a pure white on its abdomen. The blue shark is one of the fastest growing species of shark, ranging in size from1.8 to 3.8 m and weighing 29 to 55 kg. The life span of blue sharks is unknown but it is estimated that they can reach a maximum age of 20 years. Pronace. glauca is found in both inshore and offshore waters in the Atlantic Ocean, as well as adjoining seas, approximately 500 N to 500 S. The blue shark is the most widely distributed of all shark species. The blue shark prefers near surface temperate water, ranging from 13 to 180C, but can tolerate from 7 to 270C. The blue shark is an opportunistic feeder but prefers feeding on small pelagic schooling fish such as herring, mackerel, sardine and anchovy. The only natural predators of the blue shark are other larger shark species (Boyle et al, 1998).
