Sharks are now facing the greatest threat to their existence in their 450 million-year history.This newsletter, Emperors of the Deep, shines a spotlight on the key issues affecting sharks. In addition, we discuss the exciting new scientific discoveries about them.
In Richard Ellis’ Book of Sharks, written in 1975, mankind then knew of 250 species of sharks. Scientists have continued to find new shark species over the past 50 years and today the number has doubled to over 500 known species of sharks around the world. The discovery of new shark species continues into 2020.
An international team of researchers has discovered four new species of tropical sharks that use their fins to walk in ocean waters off northern Australia and New Guinea. Christine Dudgeon, a biologist at the University of Queensland, published a report January 21, 2020 in the journal Marine & Freshwater Research. She documents the discovery of four new species, bringing the total number of known walking sharks to nine. The sharks use their fins to walk in very shallow water and the ocean bottom. At less than a foot long on average, walking sharks can withstand low oxygen environments and walk on their fins out of water for brief periods.
This ability allows them to prey of small crustaceans and mollusks. The new species evolved after the sharks moved away from their original population, became genetically isolated in new areas and developed into new species about two million years ago. The new number of known sharks is still probably not known as scientists continue their explorations.
2019 Shark Attack Data Released
The 2019 shark attack data was recently released from the International Shark Attack File (ISAF) which is the definitive database in the world on shark attacks. The worldwide total of unprovoked attacks equaled 64, well below the five-year average (2014-2018) of about 82 incidents annually. Fatalities remained stable with five, in line with previous years. The United States remains the country with the highest number of shark attacks and represents two-thirds of the world's shark attacks. The country had 41 attacks in 2019 which is below the average 50-55 attacks a year historically. Within the US, the state of Florida represents the highest number with about one-half of the U.S. total. So, Florida represents about a third of the world attacks and the U.S., about two-thirds again for the world.
Why the attacks are down is due to Florida. Blacktip sharks usually migrate in the winter months from North Carolina to southern Florida. Due to global warming, the sharks can are stopping their migration in northern Florida, around Jacksonville. Since shark attacks are highly correlated to surfers and the sharks are no longer near where the surfers are, the number of attacks is falling. This drop has occurred for the past 2 years. I have a detailed chapter about this issue of global warming and sharks in my upcoming paperback book, to be published on May 26th.
Unprovoked Attacks 64
Provoked Attacks 41
Boat Attacks 12
Public Aquaria 1
No assignment could be made 9
Not Confirmed 9 Total Cases 140
Sharks Resist Wound Infection
Researchers at the King Abdullah University of Science and Technology in Saudi Arabia are studying germs living on shark skin that keeps wounds clean of contamination. Sharks get wounds of course, but rarely exhibit infections, leading researchers to understand why.
The team began collecting mucus samples from the backs and gills of wild-caught blacktip reef sharks around the Seychelles Islands, which are located in the Indian Ocean. The team took 88 different samples from 44 sharks in five different locations. These infection-resistant microbes consist of bacteria, fungi and viruses, and the composition varies depending on the shark's location and environment. The study showed that this native bacterial community protects the sharks against infections and is maintained even after injury.
The paperback, Emperors of the Deep-The Shark reveals many exciting new discoveries on sharks and why we need these magnificent apex predators. The reader will learn new insights into great whites, hammerheads, tigers and others.