Shark Diving Protocol

Shark Human Interaction

Classification

Shark Habits

• Habitat
• Behaviour
• Diet
• Longevity
• Sharks in Danger

Shark Physiology

• Characteristics
• Senses
• Anatomy
• Reproduction
• Hydrodynamics

A. Mating Activity:

Few people have actually witnessed the mating of sharks. In big species the male orients himself head-to-head and parallel with the female. In the smaller species the male coils around the female. During mating the male usually bites on to the pectoral fin or the back of the female to hold on. Skark and batoid eggs are fertilized internally and this help the young survive better.

Shark litters rarely consists of more than 100 pups but most sharks produce far less. When pups are born they are fully developed and ready to fend for themselves.

Male sharks have a feature called claspers just after the anal fin. When mating these erect claspers are inserted one after the other into the female. Muscle forces the seminal fluid down a groove in the clasper into the female oviduct.

A horn shark’s egg case.

B. Embrionic Development:

There are three ways an shark embryo can develop: oviparous, ovoviviparous and viviparous.

In oviparous sharks the glands in the oviduct secretes a shell around the egg as it passes through. The mother then lays the egg cases in the sea.

In ovoviviparous sharks the shell is often justa thin membrane with one or more eggs in a egg case. The lining of the uterus in the egg case probaly serves as nutrients while the shark develops. They may even absorb other eggs and embryos for nutrients. In these sharks usually only one embryo survives in a uterus. The female shark have two uteri.

In viviparous sharks the embryo develops inside the mother with all the nutrients coming from the mother through either direct contact between the mother and the pup or  through “uterine milk” which bathes the embryo.

An egg case which shows the developing embryo with yolk sac.

C. Gestation:

Since sharks and batoids are cold blooded there is no specific gestation time and the rate at which the embryo develops depends on the water temperature. In general it varies from two months(some rays) to about two years(some spiny dogfish).