All About Water

Smalltooth Sawfish

Known for their elongated snout ringed with teeth, the smalltooth sawfish, scientifically called Pristis pectinata, is a rather distinctive looking fish. It belongs to the elasmobranch group of fish, which includes sharks, rays and skates. The fish in this branch have skeletons that are composed of cartilage rather than bone.  Sawfish are technically a type of ray.  However, they have a long body similar to that of a shark.  In fact, Smalltooth sawfish grow to be about 18 feet long, with some growing to as large as 25 feet.  It uses its namesake ‘saw’ to locate prey in murky water or the sand. The saw then functions as a weapon to kill the prey, which mostly consists of fish, but sometimes crustaceans.

Leatherback Sea Turtles

Coral reefs are known throughout the world for their vivid colors and importance in the marine ecosystem. They have been the subject of intense study by marine biologists and oceanographers, but today coral reefs are under threat due to various human activities.

Structure and Formation of Coral Reefs

Blue Whales

The blue whale is the largest animal to have ever roamed the earth. Scientifically known as balaenoptera musculus, these whales can span as long as 108 feet and weigh more than 330,000 pounds. Blue whales live for about eighty years. Their diet consists of tiny krill. The whales live throughout the oceans of the world; they travel from sub-polar to sub-tropical regions in a seasonal migration pattern based on the availability of their food, and during the winter subsist on their fat stores. The whales can migrate thousands of miles.

Whaling: A Devastating Industry

Commercial whaling devastated blue whale populations around the world. Blue whale-hunting began in the 19th century, but caused the most damage between 1920 and 1965. Blue whales were once considered too dangerous to hunt because of to their immense size, but the introduction of factory ships and harpoon guns made them viable prey. From that point on the whales were hunted intensely until commercial whaling of blue whales was banned in 1966, at which point the blue whale was nearly extinct, numbering at one thousand. Prior to exploitation, blue whales in the Southern Hemisphere were estimated to number around 210,000. Post-exploitation, around four hundred remained. Before their exploitation, an estimated 1,500 blue whales lived in the North Atlantic. After their exploitation, around one hundred remained. Currently, the blue whale population is estimated around fifteen thousand.

Threats to Blue Whales

The blue whale was most damaged by aggressive whaling, but it is still threatened in other ways. Although commercial whaling for blue whales is now illegal, it still occasionally occurs. The whales are also killed by boat strikes and fishing line entanglement. The whales are also threatened by noise pollution, high competition for prey, ocean vessel disturbance, habitat degradation, chemical pollution, ice entrapment, and predation by killer whales.

How Are Blue Whales Currently Protected?

A Blue Whale Recovery Plan was published in 1998 by the National Marine Fisheries Service. Current efforts to protect the whales include the Marine Mammal Protection Act of 1972, the Endangered Species Act of 1973, the International Whaling Commission, the monitoring of the status of whales off the Pacific Coast of the U.S, the monitoring of commercial fisheries’ treatment of protected species, the creation of a network that alerts marine biologists when whales that show up on beaches, and autopsies on dead whales.

Atlantic salmon, known scientifically as Salmo salar, are a bony fish that averages about 28 to 30 inches long and weighs about 8 to 12 pounds. Before migrating to the ocean, they are reared in rivers. At one time they were highly prolific and found throughout the rivers north of the Hudson. Currently, they are only known to run in 11 rivers.

Why Are Atlantic Salmon Endangered?

Atlantic salmon populations began to take a nosedive in the early 19th century. Because of industry, logging and the damming of rivers, the habitat for Atlantic salmon was severely degraded. Exploitative overfishing also contributed to the problem. The population continued to decline throughout the first half of the 20th century. By the mid-20th century, distribution of Atlantic salmon was limited to the eastern third of the coast of Maine. The population of the fish that return yearly to spawn is continuing to decline, despite conservation efforts. Today fewer than 2,000 fish return to Maine each year to spawn. Even with current hatchery supplementation, the estimated extinction risk in the next 100 years is 19 to 75 percent.

Specific Threats to Atlantic Salmon

Humans have done much of the damage that is resulting in the depletion of Atlantic salmon. Fewer juvenile salmon survive because of changes in the acidity of water due to industrial activity and accidental capture by fishermen. Those that do make it are at risk because of thermal pollution and other degradations of water quality, climate change, introduction of competitive non-native species, loss of connectivity and complexity in the habitat and deliberate poaching of adult salmon. Additionally, diseases like salmon swimbladder sarcoma virus, infectious salmon anemia and bacterial coldwater disease are creating problems, even requiring some stock to be killed off to protect those remaining.

How Can We Conserve Atlantic Salmon?

The State of Maine is a key player in the conservation of Atlantic Salmon. They have a conservation plan that addresses the impacts of recreational fishing, forestry, agriculture and aquaculture. They also helped develop the Federal recovery plan. The following steps are being taken to help rebuild the Atlantic salmon population:

• Recognition of the species as endangered, making it protected under the Endangered Species Act
• Making it a Federal violation to take salmon from protected rivers
• Making an effort to divert fish away from the turbines of hydroelectric dams
• Initiating legal action against companies that are in violation of the Federal Clean Water Act
• Prosecuting those who use illegal pesticides

An Overview of Endangered Fish and Marine Animals

Humans have left a strong mark on the world. Unfortunately, that mark sometimes comes at a hefty cost. Because of overfishing or damage to their natural habitat, many fish and sea animals are now threatened, endangered or on the verge of extinction because of overfishing or damage to their natural habitat. Atlantic salmon, leatherback sea turtles, blue whales, smalltooth sawfish, and coral reefs are just some of the creatures on the list of endangered fish and marine animals.

Endangered Fish and Marine Animals: Atlantic Salmon

Atlantic salmon once swam in every river north of the Hudson. Today, the remaining wild Atlantic salmon population can only be found in eleven rivers. Only about fifteen to thirty-five percent of eggs laid by spawning salmon will survive through the fry stage because their habitats have been destroyed by acidified water, climate change, thermal pollution, the introduction of competitive non-native species, and poaching.

Endangered Fish and Marine Animals: Leatherback Sea Turtles

Leatherback sea turtles are not only the largest species of turtle, but the largest living reptile in the world. Generally these turtles remain in the open ocean, but they return to coastal areas to breed and forage. They make the list of endangered fish and marine animals for several reasons. The turtles are ingesting marine debris, they are continually entangled in nets and fishing gear, their eggs and females are being harvested, their environment is being contaminated, and they are bombarded with infection and disease

Endangered Fish and Marine Animals: Blue Whale

Blue whales once numbered in the hundreds of thousands. Today, their population worldwide is estimated at 8,000. The blue whale’s decline is primarily attributed to the overfishing of the whaling industry.

Endangered Fish and Marine Animals: Smalltooth Sawfish

Smalltooth sawfish belong to the chondrichthyes class of animals, which includes skates, rays and sharks. This class is composed of fish with cartilaginous skeletons, rather than bony ones. Sawfish are known for their distinctive long snouts, which are ringed around with teeth that are used to locate and kill prey. Smalltooth sawfish are included among endangered fish and marine animals because of their low population growth, frequent net entanglement, and loss of habitat.

Endangered Fish and Marine Animals: Coral Reefs

Although at first glance a coral reef may appear similar to stone, it is in fact composed of tiny creatures. Coral reefs are not only alive, but they also provide a habitat for many other creatures. Currently, about two-thirds of the world’s coral reefs are damaged; ten percent of the world’s reefs are damaged beyond repair. Human activity has caused about sixty percent of that damage. We’ve condemned coral reefs to the list of endangered fish and marine animals by polluting, developing along coasts near coral reefs, mining coral for ornamental purposes, introducing non-native species to their ecosystems, and aiding climate change.