The Great Hammerhead Shark
The Great Hammerhead Shark Sphyrna mokarran
Table of Contents
Introduction …………………… pg 3-4
Biology of the species ………….pg 4-5
Ecology of the species ………… pg 5-6
SocioCultural values ………….. pg 6-7
Economic Importance ………… pg 7-8
Conservation ……………………pg 8-9
Index …………………………...pg 10-11
Bibliography……………………pg 12-14
Life on earth is greatly influenced by oceanic habitat. All species are directly and indirectly impacted by the choices made by today’s existing generations. Often times humans outweigh anthropometric value from intrinsic value of habitats they’re not familiar with or exposed to every day. Human decision making functions in a way that focuses on determining costs and benefits of a particular situation, which often leads to the perception of natural resources being seen as available resources solely there to benefit humans. When aesthetic values are neglected, species readily become endangered or extinct and natural ecosystems depleted. Species diversity can be defined as a measure of diversity within an ecological community that considers species richness and evenness of species abundance. Over 80% of life on earth lives in the ocean. Large oceanic beings have experienced a horrific decrease in population over the past century due to majority of the world’s societies living by a ‘Frontier World View’ mentality. Recent human exploitation of Elasmobranchii in particular has had an even greater impact globally than majority of society is aware of. Elasmobranchii refers to the subclass of cartilaginous fishes including sharks, rays, and Chimaera. Although each are negatively affected by human influence, I plan on focusing specifically on factors detrimentally affecting sharks throughout this essay, specifically Hammerhead sharks belonging to the family Sphyrnidae. A study conducted by Dalhousie University found that the species has experienced a significant global population decrease of over 99% from 1970-2005 (Myers et al.,
Table of Contents
Introduction …………………… pg 3-4
Biology of the species ………….pg 4-5
Ecology of the species ………… pg 5-6
SocioCultural values ………….. pg 6-7
Economic Importance ………… pg 7-8
Conservation ……………………pg 8-9
Index …………………………...pg 10-11
Bibliography……………………pg 12-14
Life on earth is greatly influenced by oceanic habitat. All species are directly and indirectly impacted by the choices made by today’s existing generations. Often times humans outweigh anthropometric value from intrinsic value of habitats they’re not familiar with or exposed to every day. Human decision making functions in a way that focuses on determining costs and benefits of a particular situation, which often leads to the perception of natural resources being seen as available resources solely there to benefit humans. When aesthetic values are neglected, species readily become endangered or extinct and natural ecosystems depleted. Species diversity can be defined as a measure of diversity within an ecological community that considers species richness and evenness of species abundance. Over 80% of life on earth lives in the ocean. Large oceanic beings have experienced a horrific decrease in population over the past century due to majority of the world’s societies living by a ‘Frontier World View’ mentality. Recent human exploitation of Elasmobranchii in particular has had an even greater impact globally than majority of society is aware of. Elasmobranchii refers to the subclass of cartilaginous fishes including sharks, rays, and Chimaera. Although each are negatively affected by human influence, I plan on focusing specifically on factors detrimentally affecting sharks throughout this essay, specifically Hammerhead sharks belonging to the family Sphyrnidae. A study conducted by Dalhousie University found that the species has experienced a significant global population decrease of over 99% from 1970-2005 (Myers et al.,
Bibliography: Abercrombie, D. L., Clarke, S. C., Shivji, M. S., 2005 Global-scale genetic indentification of hammerhead sharks: application assessment of the international fin trade and law enforcement. Conservation Genetics 6: 775-788. Baum, J. K., Myers, R. A., 2004 Shifting baselines and the decline of pelagic sharks in the Gulf of Mexico. Ecology Letters 4: 135-145. Beerkircher, Lawrence R, Cortés, Enric and Shivji, Mahmood. 2002 Characteristics of Shark Bycatch Observed on Pelagic Longlines off the Southeastern United States. Marine Fisheries Review, 64: 40-49. Gilbert, C. R., 1967 A revision of the Hammerhead Sharks (Family Sphyrnidae). Proceedings of the United States National Museum 119 (3538): 1-88. Klimley, A. P., Butler, S. B., Nelson, D. R., Stull, A. T., 2006 Diel movements of scalloped hammerhead sharks Sphyrna lewini Griffith and Smith, to and from a seamount in the Gulf of California. Journal of Fish Biology 33: 751-761. Marine Life Images (2005) Retrieved from: http://www.marinelifeimages.com/photostore/details.php?gid=&sgid=&pid=180 Maxwell, C McComb, D.M., Tricas, T., Kajiura, S.M. 2009 Enhanced Visual Fields in Hammerhead Sharks. Journal of Experimental Biology, 212:4010-4018. Mondo K, Hammerschlag, N, Basile, M, Pablo, J, Banack, S. A, Mash, D. C, 2012 Cyanobacterial Neurotoxin β-N-Methylamino-L-alanine (BMAA) in Shark Fins. Mar. Drugs 10: 509-520. National Geographic Animals: Hammerhead Shark Sphyrna (1996-2013). Retrieved from: http://animals.nationalgeographic.com/animals/fish/hammerhead-shark/ NOAA Fisheries: National Oceanic and Atmospheric Administration Project AWARE Foundation, 2011. Retrieved from: http://www.projectaware.org/about-movement Sailors for the Sea Sea Shepherd Conservation Society (2013) Retrieved from: http://www.seashepherd.org/index.php Stevens, J http://www.spc.int/DigitalLibrary/Doc/FAME/Reports/Williams_97_Shark_catch_WCPO.pdf World Wildlife Fund (2013) Retrieved from: http://worldwildlife.org/