The Biology and Ecology of White Sharks - Research Paper Example

THE WHITE SHARKS Summary and introduction The scientific name for white sharks is Carcharodon carcharias. During the season of fall, they are common around the Farallon Islands where they prey for sea lions and seals. The white sharks have an adaptation of dark back and light underbelly that blends with the surrounding environment. This helps the white sharks to camouflage from the suspicious sea lions during the hunting session. The white sharks always spend a great deal of time looking for food that may last for weeks or a month before any feeding opportunities arises. The peak in predation during the fall months relates to the rising number of elephant seals whose destination is the Farallon Islands. Studies indicate that the white sharks prefer elephant seals to sea lions and harbor seals thus feed on them more frequently (Bright, 23). Studies reveal that the white shark is vulnerable under the paramount act of the environment protection and biodiversity conservation. The review finalized that a new recovery plan should be put into place in order to remove the harmful actions and include new and efficient conservation principles. This paper was majorly developed in order to address and support the new recovery plan. The research therefore includes information on the ecology and biology of the white shark, the species’ recent conservation status, a clear description of the major threats endangering the species’ survival in the Australian water bodies and appropriate recommendations for future research. The biology and ecology of white sharks The biology of the species Other names for the white shark include the white pointer or great white shark. It is a close relative of the porbeagle shark and mako shark popular in the mackerel crook family Lamnidae. The white shark has an average stout and torpedo shaped body, its color is blue-grey to grey-brown on the upper region and white beneath, has very big serrated teeth, and unique horizontal tip lengthways the physique middle line just near the semicircular designed tail. Another physical fact about the white shark is; large apex predator that grows to at least six meters in length. Some reports that are not yet proved indicate that the white shark grows up to seven meters in length and can weigh up to a mass of three thousand kilos (Bright, 33). A unique heat-exchanging circulatory system allows the white shark to maintain a favorable body temperature of up to fourteen degree Celsius above that of the surrounding water masses of the sea. This enables the individuals to tolerate a wide range of temperatures. The life history The white shark is a species that lives for a very long period of time that is approximately sixty years but this is not certain information. Averagely the reasonable period is in between forty to fifty years according to scientists and researchers. The species has a relatively slow development and low reproductive rate with a long pregnancy period that is close to eighteen months. These features indicate a low reproduction capability that has difficulties for the vulnerability of the white shark to non-natural mortality and the rate at which populations deplete and recover. These factors have substantial defects for the conservation of the white shark species. The ecology of the white sharks The white sharks are very large, uncommon warm-blooded marine predators. The maturity for females is about 12 to 17 years while for males is about 8 to 10 years. The maximum length can be up to 6.5 meters. The white sharks reproduce only once in every 1 to 3 years and give birth to 2 to 10 pups per litter. The female white sharks develop embryos through oophagy whereby at the time of gestation, embryos feed on the eggs that are not fertilized that the female continues to ovulate during the first periods of pregnancy. The litter sizes have an estimate of two to seventeen while the maximum number of approximate term pumps confirmed by dissection of expecting females is ten. At the time of birth, the white shark measures around 120 to 150 centimeters and weighs up to 32 kilos. Approximately, the white shark grows at the rate of 30 cm per year and eventually this rate slows down as the sharks reach maturity (Bright, 40). The methodology The great white sharks are the largest predatory mammals in the ocean or sea. One prominent scientist and had a methodology that is very controversial. The biologist uses the method of tagging for his study. This helps to know the movement of the white sharks and specifically the females in order to understand the concept of reproduction. The sharks were trapped and their photos taken for the effective study of their physical appearance. The type of diet The white shark is an adaptable predator. As juveniles, approximately less than three meters, they feed majorly on finfish, rays, and shark species preceding to adding larger prey items to their standard diet. The smallest white shark known from Australian water bodies to have seal remains was at 2.7 meters. At first, the white shark commonly seems to be at fur seal and the Australian sea lion territories in the waters by approximately three meters in length and this shows the size at which marine mammals are often in their diet. These observations are dependable with vertebral isotope analysis, which shows a dietary shift to include marine mammals. White sharks of all sizes in Australia will continue to target elasmobranches and finfish in their whole lifetime. The white shark does not feed constantly and a large meal such as a seal may sustain a medium-sized shark for about a period of one week. The overall degree at which they feed is likely to depend on the type of prey. In some regions, large white sharks will feed on fur seals and Australian sea lions at territories for a short time and then shift into other locales where they switch to targeting elasmobranchs and finfish species such as snapper. Adult and sub adult white sharks have been known to scavenge on floating whale carcasses, and they may be specifically active around the region of whale standings. At times, the prey includes ocean sunfish, turtles, seabirds, and sea otters. Intensive studies in California at the Farallon Islands are a base on predatory strategies of the white shark. These studies deal specifically with predatory behaviors on pinnipeds and provide important insights into behavior in such colonies. The white sharks are always fast killers since their prey are swift in water. White shark predatory success at the Island of seal is higher within one hour of sunrise and declines faster with arise in the ambient light. The white sharks will refrain from hunting when their success rate drops. Recent studies show that white sharks spend considerable period of the year in waters with various predatory behaviors (Castro, 45). The worldwide distribution The white shark exists worldwide in coastal temperate and subtropical regions. They do exist in the tropical regions and spend considerable times in the open sea. White sharks are common in off South Africa, northern California, southern Australia, and northeastern United States. In studies, researchers track the movement of white sharks with tags. Tracking indicates that their movement is well offshore and observations of trans-ocean movements show that interactions occur between individuals from populations that are otherwise geographically widely distinct. The tracking information also indicates that when the white sharks may move for long distances to off shore areas, they will eventually return to their place of departure, and this indicates the level of philopatry. Current genetic studies confirm that white sharks can comfortably move for long distances, though there is a suggestion that the population remain genetically distinct. Samples from the research brought a concept that there is a little genetic difference between the Australian and New Zealand white shark populations though both were separate from the South Africa population. This suggests that the migration between the two populations do occur. Evidence therefore supports that white sharks exhibit philopatry and return to their natal area for biological issues such as breeding. Previously this was thought to be happening in females only but males may also display similar behavior. The movement patterns The white shark is always travelling extensively over distances covering thousands of kilometers including shelf waters and off shore excursions. Cross-ocean basin travel is common between north-west Australia and South Africa. The open shark excursions have a record for having sharks from the Farallon Islands and tagging is done at the Guadalupe Island. In the two situations the sharks were recorded moving to the same off shore region of the central eastern pacific, some participants were moving as far west as Hawaii. The study is always concentrating on the return of the white shark back to the point of tagging. This reason behind this huge movements or migration is not yet clear but it could relate to feeding operations and reproduction activities. However not all sharks that are in the migration session are not adults (Cerullo, 13). The great white shark migrations Within the large water masses of Australia, the white shark travels extensively along the east and southwest coasts as well as moving along the Tasman Sea to New Zealand. There is a possibility that the population of white sharks in Australia may also extend to areas in the tropical western pacific. In the coastal region of Australia, the movements along the shores are unique. Movements are always from South Australia to Western Australia and unfortunately, there is no observation of movement made from both west and east coasts of Australia. This may reflect the challenges of retrieving long-term tracking data rather than the lack of migration. The result is compatible with evidence of genetic population subdivision between the eastern and southwestern coastal regions of Australia. MOVEMENTS OF A WHITE SHARK OVER 9 DAYS Definitely, not all white sharks are always moving for long distances as some are always moving in between the Neptune Islands and western regions of extensive Australian bight. These kinds of patterns in movements of site fidelity are close and more or less similar to the situations in South Africa and California waters. The white shark is always travelling extensively over distances covering thousands of kilometers including shelf waters and off shore excursions. Cross-ocean basin travel is common between north-west Australia and South Africa. The open shark excursions have a record for having sharks from the Farallon Islands and tagging is done at the Guadalupe Island. In the two situations the sharks were recorded moving to the same off shore region of the central eastern pacific, some participants were moving as far west as Hawaii. The sexual segregation behavior Great records in the sexual segregation have been put into records for a wide variety of sharks. In various seasons, sex specific occurrence of white sharks is in clear studies in South Farallon Islands. There is a concept in which females show a biennial appearance and the pattern is in records annually. The case for males is for a year. From the research, there is a suggestion that the female sharks may travel significant distances to give birth copulation whereas copulation may take place close to the south Fallon Islands where the males come back yearly. Studies reveal that male white sharks are common in the Neptune Islands since they prefer cooler water temperatures than females (Castro, 63). This observation indicates that a quite complex pattern between sexes than water temperatures. The habitat The white shark is always common in the regions around rocky reefs, close inshore, outer continental shelf, surf beaches, and shallow coastal bays. On the other hand they also make open ocean excursions where both adults and juveniles cross-ocean basins. Mostly the movements of white sharks in the Australian waters occur along coastal regions of approximately 120-depth contour. Suitable white shark habitats are high seas and offshores. There is a higher population of the white sharks in the Australian waters. The threats to the white shark Primary threats These defects are majorly reducing the size of white shark population at a higher rate. Commercial fishing is a perfect example in this case. White sharks interact with commercial fishing operations along the nets or fishing lines where they are trapped as they attempt to feed on the caught fish. Secondary threats This includes the activities that rise from the trade in white shark products. These operations are illegal since they pose the threat of extinction of the white sharks in the Australian waters. The products are always expensive thus making the illegal business lucrative and at the same time risky (Cerullo, 22). The ecosystem effects The act of habitat loss or modification that results from coastal development has been rising along the New South Wales. This is considered as one of the biggest threats to biodiversity and ecosystem function as those who reside there can be displaced entirely. The improvement or loss of important habitat to the white shark therefore has the capability to impact upon the ecosystem upon which the species of the white shark relies for survival. Conclusion The total population for sharks in the Australian water bodies is not yet known. The review supports that the current situation of the white shark is vulnerable. It is therefore clear that a new recovery plan should be developed to do away with old actions and include new conservation policies. Recommendations The white shark is a unique and valuable mammal species. Strict policies should be put into place in order to protect these species from extinction. Maintenance of the coastal region is ideal in order to conserve the habitat of the white sharks. Sharks are the natural predators of the ocean. If we destroyed lions the way we are destroying sharks, the world would be in an uproar and provide protection (Cerullo, 56). We need to let the world know that sharks keep the ocean ecosystems just as much as any other fish in the ocean. We should also outlaw shark fin soup and fine heavily on anyone caught doing this horrendous finning of sharks. If we do not start now to save the sharks, many species will become extinct and future generations will be treating sharks as we look at dinosaurs. The government should do the sale of its products since they are highly valuable. This could earn the country foreign exchange thus promoting stability of the economy. Works cited Bright, Michael. Sharks. Richmond Hill, Ont.: Firefly Books, 2011. Print. Camhi, Merry, Ellen K Pikitch, and Elizabeth A Babcock. Sharks of the Open Ocean. Oxford: Blackwell Science, 2008. Print. Castro, José I. The Sharks of North America. Oxford: Oxford University Press, 2011. Print. Cerullo, Mary M, Jeffrey L Rotman, and Michael Wertz. The Truth about Great White Sharks. San Francisco: Chronicle Books, 2000. Print. Deady, Kathleen W. Great White Sharks. Mankato, Minn.: Capstone High-Interest Books, 2001. Print. Domeier, Michael L. Global Perspectives on the Biology and Life History of the White Shark. Boca Raton, FL: CRC Press, 2012. Print. Mathea, Heidi. Great White Sharks. Edina, Minn.: ABDO Pub., 2011. Print. Read More