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Classification of Sharks

Brief Overview

Sharks belong to the class Chondrichthyes (chondrichthyans), which differ from Osteichthyes or bony fish as their skeleton is cartilaginous. The class Chondrichthyes or chondrichthyans is divided into two subclasses: Holocephalii (chimaeras, elephant fish) and Elasmobranchii (Elasmobranchs: sharks and batoids such as skates, rays, torpedoes and sawfish).

Over time, sharks have been exploited by humans for various purposes, from food to medicine. However, they have often been considered as low-value fish, mainly landed as by catch of other, more profitable species. Therefore, in the past, the incentive to collect biological, catch and trade data on sharks has been limited.

In terms of their biology, sharks remain largely under-studied animals and their conservation status has not been fully assessed. In commercial terms, data on shark landings are mostly mixed with that of skates, rays and chimaeras; data on shark trade are largely unrepresentative of the true extent of exports

Sharks are one of the world's misunderstood predators, as they rarely attack humans unless provoked. Contrary to popular belief, only a few sharks are dangerous to humans. Out of more than 360 species, only four have been involved in a significant number of fatal, unprovoked attacks on humans: the great white, tiger, oceanic whitetip and bull sharks. These sharks, being large, powerful predators, may sometimes attack and kill people, but all of these sharks have been filmed in open water, without the use of a protective cage.

Humans kill approximately 26 to 73 million sharks every year, while shark attacks result in approximately five human deaths each year. Many shark deaths are the result of the harvesting of fins for shark fin soup, but large numbers of sharks are also caught accidentally by commercial fisheries.

The Main Processed Products from Sharks Include:

• Meat, whether fresh, frozen, salted or in brine and smoked
• Fins, to prepare shark-fin soup
• Liver oil, for cosmetics and pharmaceuticals
• Skin, to prepare shark-skin soup, for leather and sandpaper
• Cartilage, ground to powder and used to produce a supposed anti-cancer cure
• Teeth and jaws, in jewellery and sold as curios

The majority of shark fisheries around the globe have little monitoring or management. With the rise in demand of shark products there is a greater pressure on fisheries. Stocks decline and collapse because sharks are long-lived apex predators with comparatively small populations, which makes it difficult for them breed rapidly enough to maintain population levels. Major declines in shark stocks have been recorded in recent years - some species have been depleted by over 90% over the past 20-30 years with a population decline of 70% not being unusual. Many governments and the UN have acknowledged the need for shark fisheries management, but due to the low economic value of shark fisheries, the small volumes of products produced and the poor public image of sharks, little progress has been made.

Many other threats to sharks include habitat alteration, damage and loss from coastal developments, pollution and the impact of fisheries on the seabed and prey species.

Overview of Carcharhinus sorrah

A tropical Indo-Pacific species, recorded patchily from South Africa to southern China, and common on continental and insular shelves close inshore (20-50 m) and occurring out to 140 m. CPUE data for sharks caught in the Taiwanese gillnet fishery off northern Australia (now closed), of which Carcharhinus sorrah comprised about 20%, together with fast growth rates, early maturity and relatively high fecundity, suggest that this species is more resilient to exploitation than most other shark species. Currently, annual landings of sharks in northern

Australia (mainly C. tilstoni and C. sorrah ) are significantly smaller than historical catches. Although there is a need to monitor catches in these fisheries, current catch rates are highly unlikely to threaten the Australian population of C. sorrah , and the species is assessed as Least Concern in these waters. Intensive unmanaged coastal commercial and artisanal fisheries are, however, taking this and other carcharhinids in other parts of its range (certainly in Indonesia , other areas of South East Asia and likely elsewhere), where similar population

declines to those previously observed in Australian waters have probably occurred and are likely to continue unchecked. Tagging data from Australia suggest that stocks of C. sorrah in areas of intensive fishing are susceptible to local population decline. Carcharhinus sorrah is thus assessed as Near Threatened in South East Asia . The probability of shared stocks between Australia and Indonesia is currently being investigated and it is recommended that the status of C. sorrah stocks be reassessed in the near future. Information is lacking from elsewhere and the species is currently assessed as Data Deficient globally.

Emergence of Baby Sharks at Beaches on Arabian Gulf

This type of emergence is common and is mainly on the coast of Arabian Gulf and not very frequent or common on Gulf of Oman . These baby sharks come to shore line in search of food. As many biologist believes that sharks comes in shallow waters in search of fish, squid, rays and there other food before migration. These in not common only in UAE but has been reported else where in the world. However, emergence of larger size sharks is uncommon. These baby sharks rarely harm any body, but it is advised to avoid swimming along with them. Some biologist also believes that these baby sharks often moves to shallow waters or near to beaches to avoid predation as they become less vulnerable to bigger fishes that preys on them. These types of instances are reported from Florida also where beach was, closed four times a month due to emergence of sharks. These emergence were also for the food before there migration to warmer waters. In Cases when there is Sudden Emergence of Sharks on the Beaches, there are Certain Precautions to be taken, they are as follows:

• Even though these are not always harmful, but as a precaution stop peoples from swimming in that region.
• Put red flags on the beach
• Coat guards are advised to report the incidence immediately to the Ministry of Environment and Water
• Concerned authorities should not allow these sharks to be caught by the fishermen.

General Guidelines to avoid Getting Attached by the Shark

• Always stay in groups since sharks are more likely to attack a solitary individual.
• Do not wander too far from shore, this isolates an individual and additionally places one far away from assistance.
• Avoid being in the water during darkness or twilight hours when sharks are most active and have a competitive sensory advantage.
• Do not enter the water if bleeding from an open wound. A shark's olfactory ability is acute.
• Wearing shiny jewelry is discouraged because the reflected light resembles the sheen of fish scales.
• Avoid waters with known effluents or sewage and those being used by sport or commercial fisherman, especially if there are signs of bait fishes or feeding activity. Diving seabirds are good indicators of such action.
• Sightings of porpoises do not indicate the absence of sharks; both often eat the same food items.
• Use extra caution when waters are murky and avoid uneven tanning and bright colored clothing, sharks see contrast particularly well.
• Refrain from excess splashing and do not allow pets in the water because of their erratic movements.
• Exercise caution when occupying the area between sandbars or near steep drop offs, these are favorite hangouts for sharks.
• Do not enter the water if sharks are known to be present and evacuate the water if sharks are seen while there. Moreover, of course, do not harass a shark if you see one.