Lemon Shark in black and white

Sharks

A slow-moving filter-feeder, the gentle whale shark is the biggest fish in the sea.
A slow-moving filter-feeder, the gentle whale shark is the biggest fish in the sea.

Shipping poses substantial threat to whale sharks

As whale sharks assemble in coastal regions to spend substantial time in surface waters, experts theorised collisions with ships could be causing substantial whale shark deaths. Previously, there was no way of monitoring this threat.

Scientists from 50 international research institutions and universities tracked both whale shark and ship movements across the globe to pinpoint areas of risk and potential collisions. Satellite-tracked data from nearly 350 whale sharks was submitted to the Global Shark Movement Project, conducted by MBA researchers.

Newly-hatched deepwater ghost shark (Hydrolagus sp). Photo by Brit Finucci
Newly-hatched deepwater ghost shark (Hydrolagus sp). Photo by Brit Finucci

Rare, newly hatched ghost shark found in trawling survey

A neonate (newly hatched) ghost shark was found in the net during a trawling survey at about 1,200 metres below sea level. The survey had been conducted by NIWA to estimate the population of blue grenadier (hoki fish) at the Chatham Rise, off New Zealand’s South Island.

Its body was translucent and gelatinous, and it had two giant eyes on its pointed head—with a belly full of egg yolk. "You can tell this ghost shark recently hatched because it has a full belly of egg yolk," said Brit Finucci, a fisheries scientist from National Institute of Water and Atmospheric Research (NIWA).

There is evidence that white sharks form non-random social associations and may remain in proximity to each other to take advantage of pinniped kills.

Great white sharks have a secret social life

Florida International University (FIU) marine scientist Yannis Papastamatiou, Ph.D. candidate Sarah Luongo, and a collaborative team of researchers wanted to uncover some of the mysteries of the white sharks (Carcharodon carcharias) that gather seasonally around Guadalupe Island, Mexico. 

Galapagos shark (Carcharhinus galapagensis)
Galapagos shark (Carcharhinus galapagensis) is one of the many shark species now protected in Hawaii.

Shark fishing is now illegal in Hawaiian waters

The ban does not apply to people with permits issued by the state Department of Land and Natural Resources (DLNR), shark fishing for public safety, sharks captured for self-defence, or sharks taken outside of state marine waters with required documentation.

According to Act 51, the conditions of non-commercial permits for the take of sharks “shall include native Hawaiian cultural protocol, size and species restrictions, and a prohibition on species listed as endangered or threatened.”

Shortfin mako shark
Shortfin mako shark

Ban on fishing of mako sharks reached at meeting

At the annual meeting of the International Commission for the Conservation of Atlantic Tunas (ICCAT) last week, North Atlantic fishing nations have pledged to ban catches of the shortfin mako shark.

The efforts to secure the ban was led by the UK, Canada and Senegal. The move means that the countries agreed to end overfishing immediately and to gradually achieve biomass levels that were enough to support maximum sustainable yield by 2070 for the species, according to an article in The Guardian.

Why do fish rub themselves against a shark?

Fish rubbing themselves against a shark's body may sound as if they have a death wish, but this is precisely what some fish have been spotted doing. And it turns out that such behaviour is more widespread and frequent than one would think.

A study led by the University of Miami (UM) Shark Research and Conservation Program at the Rosenstiel School of Marine and Atmospheric Science uncovered over 40 instances of fish rubbing themselves against a shark’s skin in over ten locations around the globe.

While chafing has been well documented between fish and inanimate objects, such as sand or rocky substrate, this shark-chaffing phenomenon appears to be the only scenario in nature where prey actively seek out and rub up against a predator.

Surfers are the highest-risk group for fatal shark bites, especially by juvenile white sharks
Surfers are the highest-risk group for fatal shark bites, especially by juvenile white sharks

"Mistaken identity theory" behind shark bites put to the test

Why sharks sometimes bite humans remains unclear, but potential reasons include mistaken identity, whereby sharks are thought to mistake humans for their typical prey; curiosity; hunger; and defensive/offensive aggression.

The mistaken identity theory has received little scientific scrutiny and the visual similarity between humans and pinnipeds at the surface has been debated largely on the basis of human visual perception, rather than that of sharks.

Juvenile tiger shark
Juvenile tiger shark

Populations of tiger sharks in Atlantic and Indo-Pacific found to have evolved separately

Researchers have discovered that the tiger sharks in the Atlantic are genetically different from the ones in the Indo-Pacific Ocean, according to a study published in the Journal of Heredity on 10 August 2021.

According to co-author Professor Mahmood Shivji, director of the Save Our Seas' Shark Research Centre, the two populations had not intermingled to reproduce for a long time. “This long-term separation between Atlantic and Indo-Pacific tiger sharks has resulted in them developing into separate populations, each with its own unique genetic diversity.”

Great White Shark near a boat off Cape Town, South Africa
Great White Shark near a boat off Cape Town, South Africa

Shark tourism becoming popular in Massachusetts

Cape Cod's slow embrace of its shark reputation comes three summers after the popular vacation destination saw its first great white shark attacks in generations.

Businesses dreaded the negative perception seared into the public imagination by Jaws, the 1975 blockbuster movie about a man-eating great white shark that made its director, Stephen Spielberg, a household name.

Several years ago, there was a concern that it might have a negative impact on tourism. But we’ve been working to educate people about sharks and what we’ve actually seen is no negative impact.

— Paul Niedzwiecki, Cape Cod Chamber of Commerce

Finding sharks off the coast of Cape Cod is not hard, with some shark tour operators using the same methods that shark researchers use to find the predators: drones, or an overhead "spotter" plane, to locate sharks and direct their boats to them.