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SAVE THE BAY’S UNCOMMON GUIDE to Common Life of Narragansett Bay and Rhode Island Coastal Waters

SAVE THE BAY’S UNCOMMON GUIDE to Common Life of Narragansett Bay and Rhode Island Coastal Waters

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Fish Narragansett Bay is home to more than 100 species of fish from oceanic sharksand tuna to river herring and brook trout. Some are resident species, living in theBay year-round, while others are migratory, visiting only seasonally or accidentally.The Bay is famous for striped bass and bluefish, which are abundant from springthrough fall.

Most fish belong to either the class Chondrichthyes (cartilaginous fish, also calledelasmobranchs) or the class Osteichthyes (bony fish). Fish make up half of the more than 40,000 species of vertebrates in the world: 90% of those are bony fishand 10% are elasmobranchs.

Fish are cold-blooded vertebrates that breathe with blood-rich structures calledgills, which extract dissolved oxygen from the water. Most fish have scales and aslimy, mucus coating that protects them from disease. Many species of fish have aswim bladder, which is a gas-filled sac that inflates or deflates to maintain neutralbuoyancy in the water. Gas is taken in and expelled through the mouth and gills.Sharks, skates, clingfish and flatfish do not have swim bladders.

Most bony fish lay eggs and mate through external fertilization. The female produces thousands, sometimes millions, of eggs, which are dispersed into thewater and fertilized. Most fish eggs float, but there are exceptions such as those ofthe winter flounder. Eggs and larvae are planktonic (free floating) until largeenough to sink. Most elasmobranchs reproduce through internal fertilization andlay few eggs or egg cases, with some species birthing large, live individuals.

This section of the Uncommon Guide categorizes Narragansett Bay fish intogroups determined by body shape and/or habitat preference. Sharks and skates are cartilaginous. The bottom and rock dwellers include species that may resemblerocks, such as the oyster toadfish, or fish like the cunner that can camouflage withthe mud. Flatfish have adapted to live on the bottom with both eyes on one sideof the body. Minnows are found in the shallow tidal ponds around the Bay, havesmall bodies and are often used as bait. Fish that are found in the open water, suchas the torpedo-shaped tuna, can undergo extreme migrations at very fast speeds.Anadromous fish live in salt water but migrate to spawn in fresh water. Finally,there are those with unique shapes, such as the seahorse and various tropical fishthat are accidentally transported into the Bay.

ANATOMY OF A FISH:

Spiny dorsal finSoft dorsal fin Caudal (tail) fin

Peduncle

Lateral line

Anal finVent

Scales

Pelvic fins

Pectoral fins

NostrilsEye

Gill cover

Mouth

OCEAN

ESTUARY

SHORELINE

WHERE DO I FIND IT? Use these icons as a quickreference to where youmight find a particularBay species. Icons denote a species’ predominanthabitat; other preferredhabitats are mentionedwithin the text.

sandpaper when rubbed against the grain. Five or moregill openings can be seen on the side of the head.

The snout of the blue shark is long with a well-roundedtip. It has large, pointed and serrated teeth that are welldeveloped and packed close together in its mouth. Theblue shark feeds on smaller fish such as herring, spinydogfish and mackerel. It is also a scavenger, feeding onthe carcasses of fish, whales and other sharks.

This shark is often seen swimming lazily at the surface,basking in the sun, and is not believed to swim to greatdepths. However, it is capable of attaining great speeds.The blue shark is highly migratory and found in all of theworld’s oceans.

Relationship to People

The blue shark is the most abundant of oceanic sharks. Its presence in Narragansett Bay waters is rare, but it has been spotted near the mouth of the Bay whilemigrating up and down the Atlantic coastline. This species is considered dangerous to people, but encountersare extremely unusual, and no attacks have ever been documented in Rhode Island waters.

Like most pelagic shark species, the blue shark populationis severely threatened by overfishing. Recent research onthe potential use of cartilage to heal cancer has lead toan increase in the harvesting of these slow-growing fish.

The practice of “finning” has decimated the population ofmany species of oceanic sharks, including the blue shark.Finning is the cruel practice of removing the fins from theshark and releasing it alive. Shark fin soup is considered adelicacy in many Asian countries that receive shark finsfrom fishermen all over the world.

HABITAT:Open ocean, occasionally nearmouth of the Bay.

SENSITIVITY LEVEL:

SEASONAL APPEARANCE:Summer.

FIELD MARKINGS:Bright indigo blueback, fading to lightblue-gray on the sideswith a white under-side. Size: averages 7 to 8 feet long; cangrow up to 12 feet.

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FishSharks and Skates

COLLOQUIAL NICKNAMES: Blue Dog

SCIENTIFIC NAME:Prionace glauca

Blue Shark

Distinguishing Features and Behaviors

Sharks, skates and rays belong to a particular group offish called elasmobranchs, meaning their entire skeletonis made of cartilage rather than bone.

The blue shark is distinguishable from other sharksbecause it has a slender body and long, narrow pectoralfins. Its body is thickest at the midsection and taperstoward the head and tail. This shark has two dorsal fins— the second is about half the size of the first — and anasymmetrical tail.

This animal gets its name from the distinctive blue coloring that fades to white on its underside. When the shark dies, the blue coloring turns gray. The toughskin is composed of hard scales that are abrasive like

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LEFT TO RIGHT: Bayberry (pg. 42)and beach plum (pg. 43) are justtwo of the 20 native drought- and salt spray-tolerant plantspecies present in the Save The Bay Center coastal buffer.

Narragansett Baykeeper John Torgan (right)with his father Philip exhibit their catch ofthe day, a bluefish (pg. 190).

Long-finned squid, pg.114

Harbor seal, pg. 290

Mallard, pg. 244

Harp seal, pg.292

Northern sea robin, pg. 166

COLLOQUIAL NICKNAMES: Common Skate,

Skate, Raja

SCIENTIFIC NAME:Raja erinacea

Little Skate

Distinguishing Features and BehaviorsLike rays and sharks, skates belong to a group calledelasmobranchs, which includes all fish with a skeletonmade entirely of cartilage. One of the more commonspecies of skate found in Narragansett Bay is the littleskate. Its body is shaped like a flattened, rounded triangleand is well-adapted for life on the bottom of the Bay.The skate is armored along its back and tail with sharpspines that are used defensively, but it is not a sting ray.Females have more spines than males.

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Egg Case

Unlike bony fish, skates lack the mechanism to pump oxygenated water over their gills. Because skates spendmost of their lives on the bottom, they breathe throughspecialized organs called spiracles, which are slitlike openings near their eyes. Water is taken in through thespiracles, passes over the gills and then leaves the bodythrough five pairs of gill slits underneath.

The skate has many rows of blunt teeth, resembling sand-paper, that help grind food between two well-developedjaw plates. Skates feed on a diverse diet of shellfish, crabs,sea squirts, worms, amphipods, squid and small fish.

Male skates are distinguished by two long claspers alongtheir pelvic fins, which they use to hold onto the femaleand transmit sperm. Little skates copulate many times in a year. The female lays two large eggs that develop insidecapsules, or egg cases, which are often found attached to seaweed. The empty black capsules wash ashore afterthe young skates have hatched. Resembling square coinpurses with prongs at each corner, the capsules are commonly called “mermaids’ purses.”

Relationship to PeopleThe little skate is quite common in Narragansett Bay. It has been increasing in numbers since 1970 and is now one of the dominant creatures in bottom-fish communities. They are frequently strung together andused to bait lobster pots. Because they reproduce slowly,their populations could decline if overexploited.

Historically, skate have not been a commercially importantspecies, but it is becoming more popular as a food fish,frequently marketed by its Latin name, Raja. Skate wingsare sometimes cut into small, round pieces and falselymarketed as scallops.

HABITAT:Shallow water, sandyand muddy bottoms.

SENSITIVITY LEVEL:

SEASONAL APPEARANCE:Spring, summer, fall.

FIELD MARKINGS:Light brown to grayon the back, palertoward the edges ofthe pectoral fins;white or gray belly.Size: averages 16 to20 inches long, 8 to16 inches wide.

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FishSharks and Skates

Makos range the world’s tropical and temperate oceans,but appear off the Rhode Island coast in summer tofeed on the abundant foraging species’ schools.

Relationship to People

While mako sharks have been known to attack humans, such attacks are extremely rare and none have beendocumented in Rhode Island.

Makos are considered excellent table fare and are targeted by recreational and commercial anglers. Thestate record fish weighed 718 pounds.

While the official status remains unknown, populationsof makos and other large coastal sharks have declinedsignificantly since the 1970s and are now the target offederal regulations. Mako populations have sufferedworldwide as a result of fishing pressure and bycatch in the tuna and swordfish fisheries.

HABITAT:Open ocean alongthe Gulf Stream, generally in deepwater, but may rangein close to the mouthof the Bay to chasebluefish and otherbait species.

SENSITIVITY LEVEL:

SEASONAL APPEARANCE:Summer.

FIELD MARKINGS:Gray to cobalt blue.Size: up to 12 feet.

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Fish

COLLOQUIAL NICKNAMES: Shortfin Mako, Atlantic Mako

SCIENTIFIC NAME:Isurus oxyrinchus

Mako Shark

Distinguishing Features and Behavior

Sharks, skates and rays belong to a particular groupof fish called elasmobranchs, meaning their entireskeleton is made of cartilage rather than bone.

The shortfin mako is an apex predator of the oceanand is noted for its agility and speed (over 30 milesper hour). When hooked, makos have been known tomake spectacular, cartwheeling leaps. They havecompact torpedolike bodies with a set of serrated triangular teeth in rows.

Makos are primarily piscivores, feeding on other fish such as bluefish, herring, mackerel and smalltunas. They have also been known to eat some invertebrates, like squid.

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Shortfin Mako

Sharks and Skates

A family of Canada geese (pg. 232) walk the Save The Bay Center grounds.

Floating moon jellies (pg. 56) on view at the Save The Bay Exploration Center.

LEFT TO RIGHT:A spider crab (pg. 96),blue mussels (pg. 104)and a purple seaurchin (pg.134)cohabitate in a touchtank at the Save The Bay ExplorationCenter.

Short-spined brittle star, pg.140Save The Bay worksto restore the Bay’shistoric eelgrass beds(pg. 2), home toflounder, scallopsand crabs. Photo by Tom Freeman.

Oyster toadfish, pg. 168 Asian shore crab, pg. 66