Harbor (Common) Seal (Phoca vitulina)
Actually, many varieties of seals reside in the North Atlantic and Gulf of Maine including the gray seal, ringed, ribbon and hooded varieties among others. The color and pattern of the harbor seal coat is generally gray to brownish-black and may vary between regions and even between individuals in a pod. Most notable are the spots, rings and blotches, which are generally more numerous on the back than on the belly. Mature adults typically grow to a length of 4 1/2-5 1/2 feet and weigh 175-275 pounds. Harbor seals' diets consists mainly of fish, cephalopods and crustaceans but they known to be opportunistic feeders and will vary their diet based upon season, location and availability.
Atlantic White-Sided Dolphins (Lagenorhynchus acutus)
An abundant species found only in the North Atlantic, these dolphins generally habitate from the waters just south of New England and north to the Arctic. Atlantic white-sided dolphins are typically sighted traveling in pods of 50-100 but occasionally in "superpods" with numbers as large as several thousand. They appear to be very nomadic, rarely remaining in one spot for long, and research does not suggest any set seasonal migrations. Atlantic white-sided dolphins generally grow to 5-8 feet as mature adults and weigh 300-600 pounds. They have a distinctive white and yellow stripe along both sides and a tall erect dorsal fin midway on the back. Dolphins feed on single prey which generally include a combination of small fish and squid. Females bear a single calve in mid-summer and may reproduce annually. They are believed to reach maturity at 6-10 years and live for 25-30 years.
Harbor Porpoise (Phocoena phocoena)
Also known as the common porpoise, they range from Cape Hatteras to Greenland in the North Atlantic and are the most abundant cetacean in the Gulf of Maine. They are often found in near shore or coastal areas and are known to frequent bays, rivers, estuaries and tidal channels. They have a small head with rounded face, triangular dorsal fin with a sloped trailing edge and short slightly rounded flippers. Common porpoises typically grow to 4 1/2-6 feet and are dark gray or deep brown in color. Because of their neutral color and tendency to be reserved and shy, porpoises seem to blend in with the ocean wash often making them difficult to see except on calm days. They often travel alone or in pairs and are only occasionally seen in large pods. Harbor Porpoises feed on small singular prey such as herring, mackerel, cod, pollock and squid. Research estimates a life expectancy of 24 years.
Shortfin Mako Shark (Isurus oxyrinchus)
The Shortfin Mako is a large, fast and dangerous species of shark. They average 7 - 8 feet in length but can reach lengths of up to 12-13 feet and weigh up to 1,000 pounds. Mako sharks are deep blue in color but white underneath. They are the fastest swimming species of shark and can travel at speeds of up to 30 mph. Makos have been known to attack swimmers and small boats, but generally do not remain inshore yet further out to sea. Their diet includes a variety of fish including anchovies, mackerel, sardines, tuna, swordfish and squid. They also prey upon other sharks such as the Blue shark. Mako sharks are a favorite food of many people and also a popular sport fish, known to be exciting and extremely dangerous to catch.
Basking Shark (Cetorhinus maximus)
This is the second largest fish in the world, second only to the whale shark. They can reach lengths of 35-45 feet and weigh up to 4 tons. Basking sharks are filter feeders, using large bristle-like structures called gill rakers to catch plankton as water passes through their mouth and filters over the gills. This species of shark is typically grayish-brown or grayish-blue in color with a strong crescent-shaped tail fin, conical snout and gill slits which extend from the top to bottom of its large mouth. They are generally solitary creatures but may sometimes be seen traveling in small schools. Basking sharks swim slowly (traveling at 3 mph or less) and near the surface, giving rise to their nickname "sun fish". They are non-aggressive and are considered harmless to people. Basking sharks range throughout the north and south Atlantic Ocean, Mediterranean sea, and north and south Pacific Ocean. They generally migrate to deep waters in the winter, but can often be seen near coastal waters during the summer and fall months.
Blue Sharks (Prionace glauca)
Blue Sharks are found in abundant numbers throughout the Atlantic, Pacific and Indian Oceans. They can be found both inshore and in offshore waters. In cooler waters as in the Gulf of Maine, Blue sharks tend toward the surface and can often be spotted. They are very easily recognized as they have a distinct coloration; deep blue on top which tends toward a vibrant blue on their sides and white underneath. They have long slender bodies, reaching 13 feet in length with a pointed snout and long pectoral fins. The tail fin has an upper lobe which is much larger than the lower. Blue shark diets include squid and many types of fish such as haddock, cod, pollock and mackerel. They are known to prey upon larger fish such as swordfish & tuna and may sometimes eat seals.
Giant Bluefin Tuna (Thunnus Orientalis)
The Giant Bluefin can reach lengths of up to 10 feet and weigh 1,500 pounds, making them the largest species of tuna and largest bony fish in the world. They are found in all the world's oceans and are known to quickly migrate vast distances in search of food, up to 6,000 miles and more in just 50 days. Giant Bluefins have torpedo-shaped bodies and the ability to retract their pectoral fins and eyes, making them able to obtain speeds up to 55 mph in short bursts. Their diet consists mainly of smaller fish, squid, crab and shrimp. They are a favorite among fishermen as just one can net $5,000-$20,000, even much more in Japan where sushi is an expensive delicacy. Due to their popularity, there is growing concern that Giant Tuna are fast becoming a depleted source. Research estimates that the worldwide population has declined by more than 70-80% in the last 20 years and nearly 95% since the 1960's.