Large Cetaceans (Whales)

To keep things simple, only a few varieties of whales are reviewed
below. In Medieval times the whale was the “Monster of the Deep” or a
“Leviathan”, stalking the seas in search of wayward travelers. Those who had been unfortunate enough to be blown too far out to sea would would come back with stories of these ferocious giants. In practical terms, they were essentially left to their own and rarely hunted .

The Blue Whale (Balaenoptera musculus)

The Blue whale is the largest animal ever to exist on earth,
growing to a length of 33m (110ft) and weighing as much as 190 tons but usually much smaller. The head of the Blue whale forms up to a quarter of the total body length. They can be found in the northern and southern hemispheres and in tropical climes. Blue whales are migratory and can travel enormous distances to mate in the cold waters in the winter s and feed in the warm waters of the summers. Blue whales being Baleen take tons of water into its mouth and filtering out the fish or krill with its baleen plates. A medium-sized Blue whale can eat over 4 tons of krill a day.

The Humpback Whale (Megaptera novaeangliae)

The Humpback whale It is easily identified at close range by its knobby head, long flippers the black and white coloration on the underside of the flukes. It is one of the most energetic baleens known for its spectacular breaching, flipper-slapping and lobtailing. No two Humpback whales look exactly alike. Humpbacks are highly inquisitive and will approach boats quite closely, showing little fear. During breeding season the Humpback males are known for singing the longest and most complex songs in the animal kingdom. Early mariners used to a believe these were “sirens songs” intended to seduce them off course and into an ill fate.
The Humpback whale has a more robust body than other Baleens. It's back and flanks are grey or black with an area of white on the throat and belly. It has a slender head, which constitutes up to one-third of its total body length. The top of the head is flattened and covered by any number of fleshy knobs or tubercles. The lower jaw has a rounded protuberance near the tip and is covered with similar tubercles to those on the head. Humpback whales are wide ranging and can be found virtually worldwide, but with apparent geographical segregation between at least ten populations. Although some mixing does occur between these populations there has probably never been any contact between the Northern and Southern hemispheres.
Humpbacks are strongly migratory, seasonally migrating from polar  feeding grounds to warm temperate to tropical breeding grounds.

The Sperm Whale (Physeter macrocephalus)
Length: male 15.8-18.5m (49-59ft) wt. 45-70 tons, female 10.9-12m
wt. 15-20 tons.
Although the Sperm whale is easily identified it rarely shows much of its body above the water. This whale has a very distinctive huge squarish head occupying at least one-third of its body and projecting, often up to 1.5m (5ft), well beyond its lower jaw. The large head contains a cavity called the spermaceti organ which is a mass of
web-like tubes filled with a yellow wax. This organ is believed to be used in maintaining buoyancy and may also be used to focus sonar clicks used to assist in its navigation.
The Sperm whale has a robust body with corrugations in the skin giving it a prune-like appearance. The skin is dark grey or brownish grey. It is paler at the front of the head and on the belly, with white fringes to the mouth particularly in the corners.
Food: Squid, octopus, fish - rock fish, skate, angler fish, lumpsucker,
cod, brown, ragfish, rough fish, groper, king-fish, eels.
The Sperm whale is found in the deep waters of all seas except close to ice edges. It is most common in submarine trenches at the edge of the continental shelf but may occur inshore where water is deeper than 200m
(655ft). Migration to favored areas for feeding and breeding may be undertaken however females undergo less extensive seasonal migration than males, usually only to 40°north and south of the Equator. Males regularly travel to 65°north and 70°south. Winter is spent in temperate
and tropical waters. Some populations are resident year-round.

Small Cetaceans (Killer whales and Dolphins(Odontocetes))

The (Orca) Killer Whale (Orcinus orca)
Legendary in sailor lore, They would travel in groups and attack even the largest of sea going beasts.

The Killer whale is the largest member of the dolphin family. This distinctive jet-black, brilliant white and grey marked, huge dorsal finned male, makes this animal relatively easy to identify. The female and juvenile, at a distance however, can be confused with a dolphin.
The Orca can grow to a length of (23ft) and weigh 4-5,000 kg in the male and 6.6m (21ft) 2.5-3,000 kg in the female.
The head of the Killer whale is conical-shaped. It has an indistinct beak with a conspicuous white oval patch above and behind the eye. It's jaw is broad with relatively few large conical teeth, 10-12 pairs in each jaw, and very powerful muscles to the rear of the upper jaw. These aid the retainment of large prey that would normally resist capture.
Despite it's name, the Killer whale has never hurt a person in the wild.  It is inquisitive and approachable and aggression within a pod is rare.  The pod is a close-knit family group and is stable from one generation  to the next. It's members usually stay together for life. These groups  of closely related pods (clans) often develop their own dialects. More  Killer whales live in cooler waters, especially polar regions, than  tropical and subtropical Regions, but they are found in all seas.
The Killer Whale has one of the most varied diets of all whales.
Although it has been observed feeding upon penguins, seals, porpoise and  large baleen whales it's reputation for doing so is probably exaggerated. For most Killer whales the diet appears to be primarily fish such as salmon and cod, and squid. The consumption of birds, penguins, sea turtles, seals, and porpoise most likely depends on the availability of their staple food sources.

Dolphins (dolphinidae) And Porpoises (Phocoenidae)
These are the Good luck charms of the ancient Mariners and even the modern day seamen. By Lore the sight of a dolphin or school of dolphins would indicate good sailing ahead and or the best wishes of the Sea Gods. In the earliest of seagoing times, it is believed that the dolphin might have been construed as the fabled Mermaid of sea lore. As a role-playing encounter their gregariousness and playful spirit can offer color anfd flavor to any storyteller’s open sea journeys.

Dolphins and porpoises are considered by many to be the most intelligent non-human mammal on the planet. They tend to be very social animals; they like to live in groups. Sometimes people come across huge schools or groups of dolphins, as many as thousands together. Dolphins and  porpoises are found in virtually all oceans and major seas of the world.
One family, the river dolphin, is even found in large freshwater rivers  such as the Amazon in South America and rivers in China and India. All dolphins and porpoises use echolocation, which is similar to the sonar used on ships. Dolphins and porpoises produce a sound in the air passages in their heads, which they then send from the front of their heads.

Popoises generally range in size from 5 to 6 ½ feet and weigh around 100
to 225 lb. The slightly larger Dolphin can be 5 ½ to 7 ½ feet in
length and weigh as much as 275 lb. They usually feed on the local fish.

Whales:

Str * , Dex x3, Stamina x5, intelligence x1, perception x2-4, wits x2,
Melee x1
Attacks: whales are more likely to do harm incidentally than by intention. But you could consider Ramming at ¾ Str and maybe a tail whip for ½ Str.
*Variable but no less than 7 for the smallest of whales and maybe as much as 17 for the largest

Dolphins and Porpoises:

Str x4-5, Dex x5, Stamina x5, Charisma x2-3, Percep x5(Listening),
Intelligence x2?, Wits x4
Alerness x3, Athletics x2, Acrobatics x1-3, Empathy x1-3,

Attacks: Bite Str and ramming at Str +3

Orca

Str x5-8, Dex x5, Stamina x5, percep x4, intelligence x1, wits x4,
alertness x2, melee x3, athletics x3, acrobatics x1

Attacks: Bite