Key Takeaways

• The oceanic whitetip shark's population has declined by over 70% in fifty years.
• The Pondicherry shark faces extinction. It used to be among the 25 most wanted lost species list by Global Wildlife Conservation before it was rediscovered in India.
• It is estimated that only 250 Ganges sharks are left in the world today.

Introduction

The Most Endangered Shark Species

The Oceanic Whitetip Shark

• The wceanic Whitetip is a medium-sized, gray-white, critically endangered shark species. The shark has a white tip on its fins and grows to 13 feet long and about 200 lbs in weight. It has a life span of up to 25 years.

 

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• According to Ocean Info, the oceanic whitetip shark's population has declined by over 70% in fifty years.

• It faces the threat of overfishing by commercial and recreational fisheries because it is a popular source of food (its fins are regularly used to make shark fin soup), and it's valued for its leather.

• According to AZ Animals, it achieves sexual maturity is 10 to 15.8 years.
• Females have a gestation period of 10 to 12 months. It is estimated that "their reproductive cycle is biennial, where sharks give birth on alternate years to litters ranging from 1 to 14 pups (average of 6). Larger sharks are known to produce more offspring."

• The oceanic whitetip needs open tropical and temperate seas to thrive. It inhabits offshore in the open ocean, on the outer continental shelf, or around oceanic islands in deep water areas.
• According to NOAA Fisheries, the species lives in the "upper part of the water column, from the surface to at least 200 meters (656 feet deep). The shacks have a strong preference for the surface mixed layer in warm waters above 20°C, and are therefore considered a surface-dwelling shark."

The Pondicherry Shark

• The Pondicherry shark is a critically endangered shark species. It has a pointed snout and grows to approximately three feet in length. The shark has a black tip on its pectoral fins, lower caudal fin, and second dorsal fin.

 

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• Pondicherry sharks used to inhabit the Indo-Pacific and off the coasts of India and Pakistan. They were thought to be extinct between the 1970s and 2011. However, they were rediscovered in India.
• The species faces extinction. It used to be among the 25 most wanted lost species list by Global Wildlife Conservation before it was rediscovered. 
• It is threatened by unregulated and heavy sport and commercial fishing in its habitat, as its meat is used as food.
• The Pondicherry shark is viviparous, which can be defined as "a reproductive mode where the embryo develops inside the mother's body." The birth size for females is around 13 inches long, and sexual maturity is attained at a length of over 24 inches.
• It appears that the species' breeding habits haven't been studied.

• The sharks favor the coastal waters of Indo-Pacific, but are rarely sighted today.
• According to Planet Shark divers, the Pondicherry shark typically inhabits inshore waters. Some reports also say the shark could be found in rivers, including Hooghli and Saigon rivers. In 2016, scientists confirmed that the Pondicherry shark is tolerant of low salinity.

The Great Hammerhead Sharks

• The great hammerhead sharks are the largest hammerhead shark. They grow to approximately 15 to 20 feet and 900 to 1,280 pounds. They are easily identified by their hammer-shaped snouts and have a life span of 20-30 years.
• .Unique head gives the shark three key advantages, according to science. It gives a wider field of vision (though limiting the ability to assess the distance), hosts "special sense organs, called ampullae of Lorenzini," electricity. which detect electricity and can easily locate prey, and helps the shark take quicker turns.

 

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• Great hammerhead sharks are critically endangered, and their number has decreased by around 80% in the last 25 years across multiple regions.

• The great hammerhead sharks are threatened by killer whales, which are their only natural predators.
• They also face threats is overfishing and bycatch by humans. They are hunted for fins ("prized in the Asian seafood market"). Furthermore, they suffer the consequences of habitat degradation.

• According to AZ Animals, the great hammerhead shark's age of sexual maturity is 8-9 years.
• Females can breed once every two years, which is considered slow and said to contribute to the decline in population. It has a gestation period of 11 months and the shark's litter size is 6-42 pups.

• The great hammerhead sharks live in tropical waters around the world. They inhabit shallow waters over continental shelves and island terraces.
• Some populations can be found in Florida and the South China Sea. These sharks migrate closer to the poles in the summer months. Other populations are located in the Atlantic Ocean, Indian Ocean, Pacific Ocean and the Mediterranean Sea.

The Ganges Shark

• The Ganges shark is rare and critically endangered. They are brownish-grey in color, with stocky bodies, a broad snout, and small eyes. They measure about 2 feet long at birth and grow to between 5 and 6.5 feet long.
• The shark resembles the bull shark in size and shape. It mostly eats freshwater rays and bony fish.

 

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• It is estimated that only 250 Ganges sharks are left in the world today.

• According to AZ Animals, the sharks are mainly threatened by human activity, such as the construction of dams, habitat pollution, increased river use, the clearing of mangroves for fuel, and hunting.
•  Overfishing is another major threat to the species. As per We Love Sharks, the Ganges shark is fished for its jaws and fins. This has led to its depletion in India, prompting the Indian Government to completely ban people from hunting for it.

• According to Planet Shark Divers, research shows that it is viviparous.
• Planet Shark Divers also states that "the litter size and gestation period of the Ganges shark are unknown. However, it could be similar to other river sharks, characterized by long gestation, slow growth, delayed maturity, and small litter size." Researchers assess the reproduction rate as low, though it is not certain.

• Ganges sharks are river sharks, as they survive in freshwater. They are typically found in the middle to lower reaches of a river.
• Their typical habitat includes rivers, inshore marine, and estuaries in India and Bangladesh, particularly the Brahmaputra, the Ganges, and Hooghly rivers.

The Daggernose Shark

• Daggernose sharks are rare and critically endangered sharks. According to Shark Research, daggernose sharks have an average lifespan of up to 20 years and grow to about 1.5 m in length.
• Their long and flat snouts and pointed tip make them distinctive. They mostly eat small fish.

 

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• Daggernose sharks are critically endangered and thought to be on the brink of extinction, due to being regularly hunted for food and caught as bycatch. Recreational fishing is also a threat.

• They mate at the end of the rainy season, and gestation lasts for one year. However, they can change their reproductive cycle times by around four months, depending on where they are. Females give birth to live young ones every other year.

• The sharks prefer muddy habitats such as estuaries, mangroves, and river mouths.
• They thrive in shallow tropical waters and are found along the northeast coast of South America, including Brazil, Guyana, and Venezuela, where they prefer depths of between 10 and 130 feet.

Research Strategy

Key Takeaways

• In areas like the Caribbean and Indonesia, where the tiger shark populations have declined, overgrazing by these herbivores has resulted in a 90-100% loss of seagrass.
• A study published in Biological Conservation showed a 71% drop in the populations of tiger sharks over three generations.
• Tiger sharks have carbon sinking capabilities. According to Becca Selden, an assistant professor of biological sciences at Wellesley College, "Long-lived vertebrates can act as carbon sinks when carbon consumed at the ocean surface is transferred to the deep ocean by feces and/or dead carcasses falling to the ocean floor."

Introduction

Overview of Tiger Sharks

• Tiger sharks are large apex predators, growing as long as 17 ft (5 m) and weighing more than 1900 lb (860 kg). On average, they are the fourth-largest sharks, behind the whale shark, basking shark, and great white shark.
• These aggressive, cold-blooded predators have an affinity for tropical and warm-temperate waters. They get their name from the tiger-like dark stripes and spots on their bodies, which are more prominent on the young fish.

 

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• These mostly nocturnal predators have been nicknamed “garbage eaters” as they are known to eat a wide variety of food, such as seals, fish, birds, and even inedible man-made junk.

Importance in Regulating the Food Chain

• In Western Australia's Shark Bay, tiger sharks mainly eat sea cows also known as dugongs, which, in turn, feed on about 88 lb (40 kg) of seagrass daily. Other sea herbivores like manatees and green sea turtles also consume seagrass.
• Seagrass plays a critical role in the oceans. For example, young developing sea animals like shrimp, fish, and crabs tend to hide within the seagrass. Seagrass also produces oxygen that sustains marine life.
• A flourishing seagrass meadow significantly contributes to carbon capture, as it stores twice as much carbon dioxide in a square mile as a typical forest. As such, the presence of tiger sharks, which prey on sea cows, turtles, and manatees in Shark Bay, for instance, is critical to maintaining a thriving seagrass population and the dependent ecosystem. In areas like the Caribbean and Indonesia, where the shark populations have declined, overgrazing by these herbivores has resulted in a 90-100% loss of seagrass.
• It is worth noting that the mere presence of tiger sharks in the area inspires green turtles to move, which "prevents them from overgrazing all the seagrass" on a specific territory.
• Furthermore, tiger sharks have carbon sinking capabilities. According to Becca Selden, an assistant professor of biological sciences at Wellesley College, "Long-lived vertebrates can act as carbon sinks when carbon consumed at the ocean surface is transferred to the deep ocean by feces and/or dead carcasses falling to the ocean floor."
• She also believes that, like grey reef sharks, tiger sharks are likely able to transfer nutrients like nitrogen to the seagrass beds through their fecal matter, which is powerful fertilizer.

Symbiotic Relationship

• Remoras, also known as suckerfish, form a mutually beneficial relationship with different species of sharks. By attaching to the bodies of sharks, remoras clean the skin of the sharks as they feed on “dead skin cells and parasites.” Meanwhile, remoras get free meals and protection from the relationship.
• Additionally, as the fourth largest species of sharks, tiger sharks have a symbiotic relationship with pilot fish. The relationship is similar to the one with remoras, only differing in pilot fish not attaching themselves to the sharks but swimming alongside them. Pilot fish also keep sharks parasite-free in exchange for protection and food.

Endangered Status

• Tiger shark populations are being depleted by the combined effect of illegal fishing techniques and the destruction of marine habitats by pollution. As such, the International Union for Conservation of Nature has listed tiger sharks as a “Near Threatened” species.
• A study published in Biological Conservation showed a 71% drop in the populations of these species over three generations.
• Also, according to a study published in January by scientists at the University of Miami Rosenstiel School of Marine & Atmospheric Science, climate-driven rise in ocean temperatures is altering the migration pattern of tiger sharks in the western North Atlantic Ocean. The study found that over the past decade, for every one degree Celsius rise in ocean temperature, these warm water-loving tiger sharks extended their migration from the US northeastern coast towards the pole by about 250 miles (over 400 km), with these migrations beginning about 14 days earlier.

 

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• With these new movements, tiger sharks are beginning to swim away from marine protected areas, leaving them more vulnerable to commercial fishing.

Conservation Efforts

• Despite the presence of charities like Shark Trust, Oceana, OP Society, and Project Aware that aim to conserve sharks and protect the oceans from the effects of climate change, tiger sharks are not specifically catered for by any charity. However, scientists at The Nature Conservancy are collecting data from two satellite-tagged tiger sharks to try to learn more about the migration patterns of the species.

Research Strategy

Key Takeaways

• Sharks are used as ingredients in cosmetic, nutritional supplement, and pet food products.
• Riblet technology derived from the study of sharkskin has been used in the development of a bio-medical film and tires, as well as in the development of products associated with the sustainable use of airplanes and the generation of wind energy.
• Substances from sharks have also been used in vaccines.

Introduction

Sharks in Technology

Cosmetics — Squalene

•  Squalene is a key part of sebum, a substance with antibacterial, anti-inflammatory, and antioxidant properties that inhibits dehydration of the skin and protects its barrier. Humans are born with abundant reserves of squalene at birth. However, this stock diminishes with aging. Squalane is a substance that mimics sebum which can be derived from plants and animals.
• Animal-based squalene is extracted from the livers of sharks, where it is used for buoyancy. Andrew Chin, marine scientist and senior research fellow at James Cook University in Australia, believes that over 60 sea shark species are sourced for the shark liver trade.
• Squalene is used in shark oil products, skincare, make-up, and in vaccines.

Nutritional Supplements

• Extracts made from shark cartilage, such as "squalamine lactate, AE-941, and U-995" are used as ingredients in nutritional supplements.
• The cartilage is derived from the skeletons of sharks and is harvested by separating the meat from the cartilage before drying it to a powder.

 

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• The supplements are used to treat cancer, retinal damage due to diabetes, intestinal inflammation (enteritis), psoriasis, arthritis, and to heal wounds. However, the effectiveness of these treatments is not confirmed.

Tires

• Sharkskin is characterized by microscopic grooves called riblets. The riblets function to reduce drag as the shark moves through the water.
• Technology based on riblets has been used to inspire the design of tires. In an article from March 2022 titled "Design of Nonsmooth Groove Tire Bioinspired by Shark-Skin Riblet Structure," researchers discussed how the application of riblets at the base of longitudinal grooves improved the performance of tires in handling hydroplaning.
• Uniroyal has employed the use of Shark Skin Technology (SST) to increase aquaplaning safety in its RainSport 3 and Rain Expert 3 tires.

 

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Sustainable Technologies

• Riblet technology, inspired by sharks, is being used on wind turbines to assist with converting wind energy into electricity, and in a bionic film in airplanes to engender fuel efficiencies.
• At Nikon, a camera is used as the eyes and a laser as the tool for a mobile robot that focuses the laser to generate riblets over the blade of a windmill. Nikon anticipated that this application of the technology in wind turbines would be most useful in harsh environments.

 

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• In aerospace, Lufthansa Technik and BASF have applied sharkskin technology in the creation of a bionic film aimed at optimizing airflow. The technology is marketed as being scalable, cost-effective, sustainable, and can be easily retrofitted. Sustainable benefits are rooted in fuel savings and emissions reductions, as well as in lower manufacturing and application footprints. This product was carded to be applied to the Lufthansa Cargo fleet of Boeing 777F beginning in early 2022.

Bio-Medical

• The riblets on sharkskin have also inspired the creation of a patterned film that is being used to inhibit the spread of viruses and inhibit bacterial growth.
•  Sharklet Technologies developed the product which claims to reduce bacterial transfer by 90% and employs no chemical or toxic additives. 
• Use cases identified for the product include in hospitality, education, transportation, restrooms, apartment buildings, museums, and entertainment venues.

Pet Food

•  Genetic material from sharks was identified using DNA barcoding in several brands of pet foods. Included in the species list were species protected under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) as well as species listed by the International Union for Conservation of Nature (IUCN) as threatened.
• Researchers could not determine how the genetic material from sharks made its way into the pet food. However, they submitted that the shark DNA could have been used in the pet food from meat ground from the carcasses of sharks disposed of after the fins were taken.
• Producers of pet food Mars and Purina both responded to the study by stating that no sharks were intentionally added to their pet food brands.
• Among the brands identified in the study as containing genetic material from sharks are Fancy Feast, Whiskas, and Sheba. The full list can be accessed at this link. 

Research Strategy