Shark - Rays-Octopus

Sharks, rays and octopus are crucial for the health of our planet, but they are some of the most enigmatic and misunderstood creatures in the ocean. Here are several ways in which sharks, rays and octopus help the world, from fighting climate change to digging through sand for their neighbors to feeding phytoplankton. Sharks have been around for a long time. The earliest known sharks evolved around 400 million years ago, more than 200 million years before the dinosaurs, and were fairly common predators. More than 2,000 species have been identified from fossil archives, compared to nearly 1,000 that we know exist today. Octopuses themselves are an important food source for moray eels, dolphins, albatrosses, sperm whales, seals and even humans. In fact, the global demand of cephalopods as food sources is raising with the decline of fish populations. Octopuses play a key predatory role in shaping communities that is unmatched by any other invertebrate. Octopuses inhabit various regions of the ocean, including coral reefs, pelagic waters, and the seabed; appear in Japanese erotic art, shunga. They are eaten and considered a delicacy by humans in many parts of the world, especially the Mediterranean and the Asian seas. This book is included three chapters: sharks, rays and octopuses. Each species included : anatomy , physiology, reproduction behavior, types, diseases and management . The main purpose of the book is to point out the interest of ocean creatures and its role in marine ecosystems and its major influence on the structure and function of marine communities. The book is concisely and clearly written and intended for veterinarians and for people directly involved in marine and aquarium animal’s health and management. It would also be of value to veterinary and marine science students.