Oceanic White Tip Shark population in Decline

Oceanic white-tip sharks are large, pelagic sharks found in tropical and subtropical oceans throughout the world. They live offshore in deep water, but spend most of their time in the upper part of the water column near the surface.

Oceanic white tip sharks are long-lived, late maturing, and have low to moderate productivity. The main threat to oceanic white tip sharks is by-catch in commercial fisheries combined with demand for its fins. Almost 90% of the species disappeared during the last decades.

They are frequently caught in pelagic long line, purse seine, and gill-net fisheries worldwide and their fins are highly valued in the international trade for shark products.

As a result, their populations have declined throughout its global range. In 2018, NOAA Fisheries listed the species as threatened under the Endangered Species Act.

Information on the global population size of the oceanic white tip is lacking. However, several lines of evidence suggest that the once common and abundant shark has experienced declines of potentially significant magnitude due to heavy fishing pressure.

For example, the oceanic white tip has declined by approximately 80 to 95% across the Pacific Ocean since the mid-1990’s. Substantial abundance declines have also been estimated for the Atlantic Ocean, including an 88% decline in the Gulf of Mexico due to commercial fishing.

Given their life history traits, particularly their late age of maturity and low reproductive output, oceanic white tip sharks are inherently vulnerable to depletion’s, with low likelihood of recovery.

Additional research is needed to better understand the population structure and global abundance of the oceanic white tip shark.

Oceanic white tip sharks are large-bodied sharks with a stocky build, and have a distinctive pattern of mottled white markings on the tips of their dorsal, pectoral, and tail fins.

These markings are why they are called “white-tip” sharks.

Their dorsal fins are rounded and their pectoral fins are long and paddle-like. The color of their bodies varies depending on where they live. They are generally-grayish bronze to brown, while their undersides are whitish with some individuals having a yellow tinge.

The oceanic white tip shark are considered a top predator, eating at the top of the food chain. They are opportunistic, feeding primarily on bony fish and cephalopods, such as squid.

However, they also reportedly feed on large pelagic sport-fish (e.g., tuna, marlin), sea birds, other sharks and rays, marine mammals, and even garbage.

The oceanic white tip shark is found throughout the world in tropical and sub-tropical waters. It is a pelagic species, generally found offshore in the open ocean, on the outer continental shelf, or around oceanic islands in deep water areas.

Although they can make deep dives and have been recorded up to 1,082 meters (3,549 feet) deep, they typically live in the upper part of the water column, from the surface to at least 200 meters (656 feet deep).

Oceanic white tip sharks have a strong preference for the surface mixed layer in warm waters above 20°C, and are therefore considered a surface-dwelling shark.

Oceanic white tip sharks are estimated to live up to 25 years, although it is thought that individuals may live to be much older (up to 36 years).

Female oceanic white tip sharks reach maturity between 6 and 9 years of age (depending on geographic location) and give birth to live young after a very lengthy gestation period of 10 to 12 months.

The reproductive cycle is thought to be biennial, with sharks giving birth on alternate years to litters ranging from 1 to 14 pups (average of 6). There is also a likely correlation between female size and number of pups per litter, with larger sharks producing more offspring.

The primary threat to the oceanic white tip shark is incidental by-catch in commercial fisheries, including long lines, purse seines, and gill-nets (among other gear types).

Because of their preferred distribution in warm, tropical waters, and their tendency to remain at the surface, oceanic white tip sharks have high encounter and mortality rates in fisheries throughout their range.

Their large, distinct fins are also highly valued in the international shark fin trade.

NOAA Fisheries / Crickey Conservation Society 2023.

One Comment on “Oceanic White Tip Shark population in Decline

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.