Shark Conservation and Biology Overview

More likely to be struck by lightning

1 in 500,000 chance

More likely to be crushed by a vending machine

2 to 3 deaths per year

More likely to be involved in a fireworks accident

~11,500 injuries annually in the U.S.

Shark deaths per year

Approximately 10 deaths per year.

Shark species in decline

Many shark species in other parts of the world are in decline due to overfishing and habitat loss.

Role of sharks in ecosystems

Sharks keep prey populations in check, remove sick and weak animals, and help maintain healthy ecosystems.

Oxygen production by the ocean

The ocean produces more than half of the oxygen that we breathe.

NOAA

The National Oceanic & Atmospheric Administration

Shark Conservation Act

Thanks to the Shark Conservation Act and the cooperation of fishermen, many shark species are on the rebound.

Endangered shark species managed by NOAA

The only species of sharks managed by NOAA that is listed as endangered is the Scalloped hammerhead shark.

Shark finning

The practice of removing a shark's fins and discarding the body at sea.

Fate of dumped sharks

They often die from suffocation, blood loss, or predation.

Shark finning ban

Shark finning has been banned in U.S. waters since 2000.

Biggest problem for shark populations

Overfishing.

Fishing rate of sharks

Sharks are being fished faster than their populations can recover.

Support for sustainable seafood

Support sustainable seafood choices.

Importance of shark conservation

Three reasons shark conservation is important: maintain ocean ecosystem balance, prevent extinction of species, support healthy fisheries.

Management of fishery species

Fishery species are managed with science-based regulations.

Distribution of dogfish

Most dogfish are distributed in the North Atlantic and North Pacific Oceans.

Areas with warmer waters

Two areas with warmer waters are the Mediterranean Sea and Gulf of Mexico.

Classification of dogfish

Domain: Eukarya, Kingdom: Animalia, Phylum: Chordata, Class: Chondrichthyes, Order: Squaliformes, Family: Squalidae, Genus: Squalus, Species: acanthias.

Skeleton composition of sharks

Their skeleton is made of cartilage.

Habitat of dogfish

Almost all dogfish are marine (live in salt water).

Buoyancy of sharks

They are negatively buoyant.

Characteristics of cartilaginous fishes

Three characteristics of this class: cartilaginous skeleton, no swim bladder, placoid scales.

Placoid scales

Placoid scales are also called dermal denticles.

Function of elastin in shark skin

Elastin in their skin acts like a spring to help them swim.

Cartilaginous fishes

Cartilaginous fishes include sharks, skates & rays.

Age of cartilaginous fishes

They have been on Earth for almost 400 million years.

Swim bladder in sharks

Do they have a swim bladder? No.

Commonly found shark fossils

Most commonly found fossils are teeth.

Number of teeth sharks typically have

Sharks typically have thousands of teeth.

Composition of shark teeth

Made of very hard substances: dentine & enamel.

Shark skin texture

Shark skin feels like sandpaper.

Gill slits in sharks

Sharks have 5 or more gill slits.

Adaptation of sharks

Primary adaptation: Highly developed senses (like smell and electroreception).

Rows of teeth in sharks

Rows of teeth: 5 to 15.

Total lifetime teeth of sharks

Total lifetime teeth: 30,000 to 50,000.

Types of shark teeth

Predatory sharks have pointed serrated teeth; bottom-dwellers have flat, crushing teeth.