Friday, January 04, 2019

Sea Challenge! Shark Quest: Protecting the Ocean's Top Predators by Karen Romano Young

Who's the apex predator of the world's oceans?

Some would say carnivorous whales such as the orca, but most would say sharks. The famous line from the movie "Jaws" calls the shark "an eating machine," and the large sharks do fit that role.

"As the top predator of the Atlantic, the white shark is like the wolf of the sea, helping to maintain ecological balance by feeding on prey such as seals--especially the weaker and less fit," says shark scientist Robert Heuter. Without predators in an ecosystem, one species may take over and a cascade of imbalance flows from there.

But the truth is that Earth's apex predator is we humans!

Sharks do fit the description of super eaters. Except for the docile plankton-feeding whale shark, they feed at the top of the food chain for ocean dwellers. Their DNA is longer and more varied than ours--because they have been around for around 450 million years, plenty of time compared to modern humans, to develop immense diversity and complexities especially in feeding skills. Some forms of sharks can invert their stomachs and get rid of indigestible ingestions, like outboard boat motors and hempen dragnets. They are also the masters of varied forms of reproduction--oviporous and viviporous, with their unborn young can be nourished either by a placenta, like mammals or by the simple expedient of having the unborn pups feed on the unfertilized eggs--oophagy--or feeding on the other embryos--adelphophagy! Some sharks can store sperm for long periods, and at least one species, a blacktip reef shark, has produced a genetic clone of itself--a case of reproduction so rare that English has to borrow a Greek term, pathenogenesis, for it.

For secondary level students, Karen Romano Young's Shark Quest: Protecting the Ocean's Top Predators (Twenty-First Century Books, 2018) puts its readers deep into the study of shark. With eight intriguingly titled chapters--"The Trouble with Sharks," "What's a Shark?" "Feeding the Beast?" "Shark Sex," "Swimming with Sharks," "What Do Shark Researchers Do at Sea?" "What Do Shark Researchers Do Onshore?" and "Citizen Science for the Sharks," offers much solid science and plenty of fascinating tidbits to make for an engaging read for shark fans and a plentiful source for research reports, one pretty much on the cutting edge of shark study and the use of technology (not all shark science is done on or beneath the water) in investigation of this amazing animal.

For young adult readers who are fascinated by sharks and fancy a bit of ocean adventure, this one is absorbing reading, especially since mankind, the real apex predator, seems to be the biggest danger to sharkdom, and for those who prefer working digitally to donning a wet suit, there is plenty of groundbreaking research to entice them into shark science here. With quite an appendix--a pictorial shark guide to the eight orders of sharks, source notes, glossary, selected bibliography, further information about clubs, smartphone apps, and even adopting a shark, websites and books, and a full index with sub-headings--this one is for the real student of the species. Says School Library Journal," "Young's interweaving of dismantled misinformation and captivating "shark truths" seamlessly leads into the activities undertaken by researchers and conservationists to better understand and protect shark populations, and Kirkus Reviews adds "Shark populations are endangered due in large part to human impact, specifically fishing and finning, and how teens can act as advocates and conservationists is provided. A must purchase for libraries and fans of Shark Week."

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