HARBOR PORPOISE

Common Name: Harbor Porpoise

Size: Length: Maximum female 1.89 m, male maximum 1.78 m.

Habitat: Cold temperate and subarctic marine waters. Coastal areas; including bays, estuaries, offshore shallows, tidal rivers and channels.

Range: Northern Hemisphere in the North Atlantic and Pacific Oceans .

Diet: Benthic fish, some pelagic fish species, and some benthic invertebrates.

Reproduction: Mating season takes place from June to August, and gestation lasts for 10-11 months. Calves average 75 cm in length at birth. Calves nurse for about 8 months.

Conservation Notes: There is some serious concern over this species and incidental catch and entanglement in gill nets and other fishing gear. The Harbor Porpoise is hunted commercially by 1 country still, and this fishery is relatively small. This species is listed in CITES Appendix II.

HARBOR SEAL

The harbor seal has a vast range, resulting in wide variations in appearance, physiology and behavior. There are at least 6,000 harbor seals in Maine water, and can normally be found in New Jersey waters from December through March. They bask on near-shore ledges and small islands in bays, harbors, and estuaries in the Gulf of Maine , and often come very close to boats due to their apparent curiosity for human activity.

They have a distinctive doglike profile with eyes set halfway between the ear and the tip of the nose. From the front the nostrils appear to have a "V" or heart shape. Their coats vary from light gray or tan to brown and red, with black or light spots. The coat often looks dark when wet, but can be very light when dry. The males are about 6 feet long and can weigh up to 250 pounds, which is consistently larger than the females who only reach about 5 feet in length.

Unlike many seal species, the harbor seal pup has a coat that closely resembles the adult coat. Some have a longer, softer white or gray coat (lanugo) when born, but they shed that coat within about 10 days. These pups are very precocious and can swim almost immediately after birth, and during the first week of life the pup often rides on its mother's back while she swims. The pups are weaned after about 30 days.

Wild harbor seals probably consume 6 to 8 percent of their body weight in food per day, depending on the nutritional value of the food being eaten. Their diet varies greatly depending on location, and includes a wide variety of fish, cephalopods, and crustaceans. Their average life span is around 25 years, although some have lived for over 30 years. However, males tend to live shorter lives, probably due to the added physical stress of fighting during breeding season.

The Harbor Seal is a marine mammal that spends most of its life in the sea, but also enjoys sunbathing on rocks or on the beach. It is a pinniped (related to walruses and sea lions) that lives along shorelines in the North Atlantic and Pacific Oceans , in temperate, subarctic, and arctic waters. Seals have a life span of about 25 to 30 years.

Anatomy : The Harbor Seal has short, thick fur, grows to be up to 6.5 feet (2 m) long and can weigh up to 375 pounds (170 kg). The whiskers (called vibrissae) help the seal's sense of touch. The nostrils are closed in the resting state.

Diet : Harbor Seals are carnivores (meat-eaters); they eat mostly mollusks (like squid and clams ), fish , and crustaceans. Seals don't chew their food. They swallow it in large chunks. They can crush the shells of crustaceans and mollusks with their flat back teeth.

Predators : Harbor seals are hunted by killer whales (orcas) , polar bears , sharks, Steller sea lions, walruses , eagles , and coyotes.

Classification : Kingdom Animalia (animals), Phylum Chordata, Class Mammalia ( mammals ), Order Carnivora , Superfamily Pinnipedia ( pinnipeds), Family Phocidae, Subfamily Phocinae, Genus Phoca, Species P. vitulina .

BASKING SHARK

Geographical Distribution

The basking shark is a coastal-pelagic species found throughout the world's arctic and temperate waters. In the western Atlantic , it ranges from Newfoundland to Florida and southern Brazil to Argentina and from Iceland and Norway to Senegal , including the parts of the Mediterranean in the eastern Atlantic . It is found off Japan , China and the Koreas as well as western and southern Australia and the coastlines of New Zealand in the western Pacific and from the Gulf of Alaska to the Gulf of California and from Ecuador to Chile in the eastern Pacific.

Habitat

Basking shark at the surface showing exposed tip of snout (far right), 1st dorsal fin and upper lobe of caudal fin, photo by Jeremy Stafford-Deitsch©

Biology

· Distinctive Features

The basking shark is one of the most recognizable of all sharks. Its massiveness, extended gill slits that nearly encircle the head and lunate caudal fin together help distinguish it from all other species. It possesses a conical snout and numerous large gill rakers modified for filter feeding. Its enormous mouth extends past the small eyes and contains many small, hooked teeth. The basking shark has a very large liver that accounts for up to 25% of its body weight. The liver is high in squalene, a low-density hydrocarbon that helps give the shark near-neutral buoyancy.

Size, Age, and Growth

Second only to the whale shark ( Rhincodon typus ) in size, the basking shark can reach lengths up to 40 feet (12 m). The average adult length is 22-29 feet (6.7-8.8 m). Size at birth is believed to be between 5-6 feet (1.5-1.8 m). The basking shark is an extremely slow-growing species and may grow to 16-20 feet (5-6 m) before becoming mature.

Food Habits

Along with the whale shark and the megamouth shark ( Megachasma pelagios ), the basking shark is one of three species of large, filter-feeding sharks. However, the basking shark is the only one that relies solely on the passive flow of water through its pharynx by swimming. The basking shark is usually seen swimming with its mouth wide open, taking in a continuous flow of water. The whale shark and megamouth shark assist the process by suction or actively pumping water into their pharynxes. Food is strained from the water by gill rakers located in the gill slits. The basking shark's gill rakers can strain up to 2000 tons of water per hour. These sharks feed along areas that contain high densities of large zooplankton (i.e., small crustaceans, invertebrate larvae, and fish eggs and larvae). There is a theory that the basking shark feeds on the surface when plankton is abundant, then sheds its gill rakers and hibernates in deeper water during winter. Alternatively, it has been suggested that the basking shark turns to benthic (near bottom) feeding when it loses its gill rakers. It is not known how often it sheds these gill rakers or how rapidly they are replaced.

· Reproduction

MAKO SHARK

The mako is a pelagic , or open ocean, shark. It's dark blue on the back and white on the underside of its body. These deep water sharks grow to 8 feet, rarely reaching a length of 12.5 feet. Its average size is 6-8 feet. The mako is highly specialized for continuous swimming, and is considered one of the fastest sharks in the water. It can achieve speeds of more than 22 mph. It has long, knifelike teeth and feeds mainly on mackerel, squid and a variety of fishes including the fast-moving tunas, swordfishes and other sharks. Marine mammals do not appear to be an important food for mako sharks.

OCEAN SUNFISH

Common Name: Ocean sunfish, Sunfish

Size: to 332 cm TL (male/unsexed); max. weight: 2,000 kg.

Habitat Type: Pelagic; marine; depth to 300 m. Seen drifting at the surface lying on its side, or swimming upright near the surface so its dorsal fin projects above the water.

Diet: Fishes, mollusks, zooplankton, jellyfish, crustaceans, and brittle stars.

Range: Tropical and temperate seas; northward to northern Norway in the eastern Atlantic, to the Newfoundland banks, the Gulf of St. Lawrence, and the coast of Nova Scotia in the western Atlantic.

Reproductive Strategy: Numerous and small eggs (300 million in a female 1.5 m long). Three developmental stages : (1) tetraodontiform-body rather elongate, no spines, caudal fin present;(2) ostracioniform-body shortened, with some large spines on body plates;(3) molacanthiform (Molacanthus)-body short and high, skin rough with minute spines.

Comments: Commercial fisheries species. Poisonous to eat.

ATLANTIC WHITE-SIDED DOLPHIN

Common Name: Atlantic White-sided Dolphin

Size: Male maximum length 2.75 m., female max. length 2.43 m.

Habitat: Temperate marine waters.

Range: Northern North Atlantic

Diet: Fish, cephalopods and some shrimp.

Reproduction: Gestation period lasts for 10-12 months and calving takes place from May to August. Young are around 1.1 to 1.2 m long at birth. The calf nurses for about 18 months.

Comments: Generally found in small (6-8) to large groups.

Conservation Notes: There are no good estimates for the population of this species, but it appears to be abundant. There is still some commercial hunting, and some are taken incidentally in fishing gear. Listed in CITES Appendix II.

BLUE SHARK

The blue shark has a long, slender body -- up to 12.5 feet -- with a pointed snout. Its upper body is dark blue, the sides are bright blue, and the belly is nearly white. This type of coloration is known as countershading .

The blue shark is a pelagic , or open ocean, shark. It may be seen in offshore surface waters near San Diego and northern Baja Califoria. Its lower jaw is narrow and lined with long, sharp, serrated teeth. It feeds mainly on fish, but it's not shy like its shallow-water or bottom-dwelling cousins, and can be dangerous to open-water divers.

The blue shark is viviparous , and gives birth to live young, or pups. A litter can have as few as four and as many as 100 pups, depending upon the size of the mother.

The blue shark is also called the blue whaler or great blue shark.