With the loss of at least 90 percent of sharks worldwide, it would seem to be urgent to protect the ones that remain. Every global study of their status has reported a more dire situation than the last, and that the targeted hunt for the shark fin trade is responsible for their catastrophic depletion.
I felt apprehensive heading out to Tiger Beach where I was supposed to enter open water in the presence of some big, wild apex predators, without any protection other than holding up my camera as a shield in case I was singled out as a snack.
It’s early afternoon. The sun is beating down and mosquitoes are humming. Another decent day’s catch is unloaded, men sweating with the effort. If it weren’t for the breeze, the stench would be unbearable. Today’s tally: more than 100 sharks, some weighing close to 1,000 pounds and reaching nearly 20 feet in length.
Researchers conclude the northward range shift demonstrates water temperatures within their preferred temperature range of juvenile white sharks are becoming harder to find.
The animals have historically remained in warmer waters in the southern California Current; Between 1982 and 2013, the northernmost edge of the juveniles' range was located near Santa Barbara (34° N).
Sleep is ubiquitous across the animal kingdom but despite anecdotal reports of sleep-like behaviour in nurse sharks and other seafloor-dwelling species, the question of whether sharks actually sleep has been intensely debated but remains unknown. A key criterion for separating sleep from other quiescent states is an increased arousal threshold. True sleep is characterised by a lack of movement that can be rapidly reversed, and a decreased awareness of surroundings.
The Lost Shark, Carcharhinus obsoletus, is already extinct, and others that are expected to follow soon include four species each of hammerhead and angel sharks, from the world’s most threatened shark families. In spite of all the press that shark conservation has received in the past two decades, no effective protection of sharks has been established, no sharks have been saved, and their decline into extinction is ever more apparent.
Knowledge of the habitat use and migration patterns of large sharks is important for assessing the effectiveness of large predator Marine Protected Areas (MPAs), vulnerability to fisheries and environmental influences, and management of shark-human interactions.
Researchers from James Cook University's ARC Center of Excellence for Coral Reef Studies examined stomach contents of reef sharks and conducted chemical analyses of shark body tissue to find out what they had been eating.
Somewhat surprisingly after pumping sharks' stomachs to identify the contents of the last meal, the most common thing to find was in fact, nothing. "These results suggest that reef sharks eat small meals infrequently and opportunistically," Lead author, Dr Ashley Frisch said.
The paper presents the reasons why large predators of great ecological importance cannot supply the rising demand for shark fins, which is driven by profits that rival the drug trade and involves the fisheries of nations around the globe. They have essentially run out of fish so are targeting sharks now that the shark fin trade has made them valuable.
Development of a vaccine against Covid-19 could come at the expense of sharks, researchers warn; A key ingredient used in vaccines to enhance immune response and increase effectiveness, squalene — an oily substance found in plants and even human skin — is particularly concentrated in shark livers.
Sharks elicit strong emotions, be it the thrill of a planned encounter underwater or fear propelled by social media and lack of information. Of the more than 400 species of sharks, it is the small family of mackerel sharks that is most iconic. These sharks prompted me to share why one of them, the salmon shark, is an especially remarkable species.
Many divers dream of the day they find themselves swimming beside a whale shark. Its gentle demeanour and huge size presents a unique humbling experience that is second to none.
Yet, there is much we still do not know about whale sharks.
Today, one of their hidden mysteries have been unlocked–their age.
Until recently, it was hard to fix a number to their age, as they do not have bony structures (otoliths) which are traditionally used to calculate the age of fish.
More and more divers are meeting sharks for the first time, and wondering, “What do they see when they pass, gazing at us gazing at them?”
