The endangered basking sharks
Richard & Charles (2000) define an endangered species as one that may become extinct if measures are not taken to avert the situation. Endangered species have a small population and are often affected by human or natural environmental changes leading to their demise and eventual extinction. Sharks as an endangered species have in the recent past elicited reactions from animal conservationists, who have staged demonstrations against the intrusion of human life activities that have led to the decline of the different species of sharks. Richard & Charles (2000) note that sharks reproduce in small numbers thus putting them in great vulnerability as compared to the other animals. The basking shark, which is the species that is the most endangered in the family of Cetorhinidae. They belong to the genus of Certohinus. The scientific name of the basking shark is Cetorhinus maximus (Marine-bio, 2012).They are called basking sharks because they like existence in the warm waters where they swim up-close to the surface as though they are basking, hence the name –basking sharks(Richard & Charles, 2000). The basking sharks are the second largest fish in the world. Research has shown that the basking shark grows to 10 meters, but some measure up to 11-13 meters in length. The average weight of a full grown basking shark weighs up to 4 tons or 9000 pounds. The female basking sharks are comparably bigger than the male sharks. The sharks have a greyish brown colour, while some may be spotted as bluish black colour. They are differentiated from other fish by their snouts which are long, conical and pointed (Sonia, 2011)
The basking sharks have also big gill slits on either side of the head. As Dean (2002) notes, the gill slits have thousands of gill rakers which help filter food in the waters. The gill rakers are shed periodically and the sharks are often seen with their mouths wide open. This is to gallop water and also is an adaptation to catch food. The sharks are covered with placoid scales and mucus lining. Dean (2002) speculates that the basking sharks have a large liver; estimated at three quarters of its body. The large liver gives the sharks buoyancy and helps it to easily balance in the water. Below is a picture of a basking shark (Source: Sonia, 2011)
Basking shark (Cetorhinus maximus)
World habitat and Range
The basking sharks are found in cold to warm temperate regions of the marine habitat. Most of them are found almost in every borderline of the Atlantic and Pacific oceans. They have also been sighted along the North coast of America, around Baja California and British Colombia during the winter and spring. The trend is reversed on the northern fringe. The animals can be found existing alone or in groups of up to 100 members in a conglomeration. The members live in areas close to the land and where there is a high concentration of planktons. The sharks feed on planktons and also possess a migratory behaviour. They can migrate periodically to areas where there is plenty of food or escape from human activities which render their life uncomfortable. These types of sharks are slow moving and are not normally associated with the numerous human attacks. Dean (2002) acknowledges that this type of sharks are normally harmless to humans and are often seen somersaulting near the surface of waters.
Feeding Habit and the Population
These types of animals are filter feeders (Sonia, 2011). Filter feeders are those that filter food substances from the waters in which they are swimming through. The basking sharks are known to gallop large quantities of water and swim with their mouths wide open at some angles. It is estimated that the sharks can gallop more than 1800 tons of water per hour. The lager gill rakers become handy in filtering the food from the waters. They normally feed on planktons, specifically the zoo plankton. The sharks also feed on small fish, fish eggs and invertebrates. Sonia (2011) points out that the basking sharks have olfactory cells that guide them to areas of high plankton concentration. Therefore human effects that ruin their habitat causing them easily migrate to other areas where they will often find it habitable. This is so due to their migratory behaviour. Another fact about the basking sharks is that they are ovoviviparous (producing living young from eggs that they hatch from within the body).Basking shark predators do exist. Some of them include the orcas. These are the killer sharks and include the tiger sharks. The basking sharks are under threat from the human activities that continues to rock their habitat thus influencing their rate of reproduction. This eventually leads to their death, hence a probable extinction of this species of sharks if urgent actions are not taken by the government where they can be spotted. On average, the shark population is candidly known. This is due to the rigorous studies of shark tagging which may not provide the correct results due to constant deaths, births and other natural phenomena that either reduce or increase the population. However report from the marine-bio organization indicates that there are more than 21,000 sharks from a record of 5200 records. This therefore leaves us speculating that the population could be more owing to the fact that tagging is globally carried out. This population has been in constant decline due to human activities of fishing and habitat destruction, forcing the sharks to migrate and even some succumbing due to the interference.
Factors affecting shark population
The most dangerous threat directed towards sharks by human life is the commercial fishing which accounts for most of the deaths witnessed in the marine life today. Sonia (2011) argues that approximately 100million sharks are killed in relation to fishing and hunting. Sharks and in this case the basking sharks, are finned (a practice where the sharks are caught and their fins cut but the rest of the body is discarded).This coupled with the ritual overconsumption have seen the population of sharks dwindle to greater levels. Sharks are hunted for the meat, fins and cartilage. In China the fins are highly sought for the medicinal value, thus putting the shark under a lot of danger.
Sharks are also affected by the ‘by-catch’ where the fishing is not purely intended to catch them but, co-incidentally are trawled along. Most undersea or deep-sea dwellers are affected by this type of fishing where the trawls trap them. Aguilar (2007) argues that the efforts of shark protection or protection offered to marine life will not succeed if the natural habitat is not well taken care of. Habitat degradation has been one of the reasons behind the decline of shark population. Sharks are known to live in a cool and secure habitat that is free from usual pollution. Here they are able to get their food as they also reside under similar habitat. Human efforts in industrialization have overseen interference with the natural marine ecosystem. For example there have been cases of ocean oil spills and effluents which are directed into the oceans as waste products. These have had the effects of clogging the breathing apparatus (gills) of sharks thus killing them. Large incidents of marine life interference from the human environmental efforts have been reported. This equally contributes towards the death of the sharks; and if appropriate actions are not taken, then the sharks will soon be an extinct animal in the marine habitat. The increase in environmental pollution and release of CFCs into the atmosphere has led to global warming. Global warming has also had an impact on shark population. This is portrayed by the rise in temperatures where the heat might even be overwhelming forcing them to migrate, and on extreme cases leading to death. This is so because the animals are cold blooded and therefore any temperatures that are beyond control will normally have adverse effects on their population.
Legislation and efforts to save the sharks
Reports from the conservationist organizations indicate that basking sharks are some of the species of sharks that are currently under threat of extinction if appropriate measures are not taken into consideration to curb the lurking menace. Human activities especially shark hunting and overfishing using deep sea trawls are some of the factors leading to the capture and destruction of these beautiful marine creatures. It is therefore pertinent that human efforts in a global consideration be taken into account in order to rectify the situation. There have been numerous efforts by conservationist worldwide that fight for the conservation of the marine environment so as to prevent shark destruction. Some of them include the IUCN which involves itself with the protection of endangered species. Many governments have introduced fishing and shark laws to help protect the marine lives. For example the Britain and Scotland introduced the Wildlife and Countryside Act (1981) and the Countryside and Rights of Way Act (CROW).Many other more governments have introduced acts and laws prohibiting excessive fishing and marine habitat exploitation that is common of human activities. Human marine pollution through oil spills and other emissions have also been banned and legal actions are taken against the perpetrators of the law. Instances as this one in the picture below lead to exploitation of sharks, and sooner or later their population will be extinct.
(Picture of a giant basking shark after being killed by fishermen) (Source: Richard & Charles, 2012)
There are strict laws prohibiting the expulsion of oil or effluent to the sea or ocean waters. The basking sharks were also added to the Bonn Convention on Migratory Species (BCMS) and therefore the North Atlantic Fisheries Commission recommended that there is no fishing of basking sharks in the area. These have gone a long way in helping rectify the situation of the basking shark exploitation menace.
Aguilar, S. (2007). On caviar, sharks and mahogany: Can CITES promote sustainable management? Environmental Policy and Law, 37(5), 376-381. Retrieved from http://search.proquest.com/docview/214151405?accountid=45049
Dean, J. (2002). Saving whale and other marine gems. Northern Echo, pp. 08-08. Retrieved from http://search.proquest.com/docview/329066867?accountid=45049
Marine-bio (2012).Basking Sharks, Cetorhinus maximus. Retrieved from http://marinebio.org/species.asp?id=193
Richard, P.R& Charles, M. (2000).Endangered animals: A reference guide to conflicting issues.USA: Greenwood Press. Retrieved from http://books.google.co.ke/books?id=f_AWCtX29-kC&pg=PA49&dq=endangered+sharks&hl=en&sa=X&ei=bVNpT5ioCIKd0AWw5rmPCQ&ved=0CFwQ6AEwCA#v=onepage&q=endangered%20sharks&f=false
Sonia, N. (2011). Basking Shark facts. Retrieved from http://www.buzzle.com/articles/basking-shark-facts.html