Rainbow Trout

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Introduction

Specific Species

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Introduction

There are three classes of fish: Jawless Fishes (Agnatha), Cartilaginous Fishes (Chondrichthyes) and Boney Fishes (Osteichthyes).  All fishes are cold-blooded vertebrates (having spines of bone or cartilage), live in water, breathe with gills and have fins instead of legs. Not all animals that live in water are fish. Whales. porpoises and dolphins are mammals. Sponges, shellfish, sea worms etc. also live in water but are not fish.

Jawless Fishes (Agnatha) are not found in French Hill Pond. These fishes are the most primitive of the fishes. They are eel-like and lack bones and jaws. There are two orders in this class: Hagfishes (Myxiniformes) and Lampreys (Petromyzontiformes). Only the Lampreys are found in freshwater. The Sea Lamprey (Petromyzon marinus) may be found off the seacoast in Maine and in estuaries but they are unlikely to travel up streams to lakes and ponds on Mount Desert Island. They prefer deep waters greater than 3,000 feet (915 meters).

Cartilaginous Fishes (Chondrichthyes) are also not found in French Hill Pond. These fishes lack bones but have well-developed jaws. They are usually found in salt water. This class includes sharks, ratfishes, sawfishes, skates and rays. The Sand Tiger shark ( Odontaspis taurus), Thresher Shark (Alopias vulpinus), White Shark ( Carcharodon carcharias), Basking Shark ( Cetorhinus maximus), Porbeagle (Lamna nasus), Blacktip Shark (Carcharhinus limbatus), Tiger Shark (Galeocerdo cuvieri), Blue Shark (Prionace glauca), Bonnethead (Sphyrna tiburo), Spiny Dogfish (Squalus acanthias), Atlantic Angel Shark (Squatina dumerili), Atlantic Torpedo (Torpedo nobiliana), Little Skate (Raja erinacea) and Cownose Ray (Rhinoptera bonasus) may be found in the Gulf of Maine but are too large to accidentally make their way into the lakes and ponds of Mount Desert Island. Some of these fishes are very dangerous.

Boney Fishes (Osteichthyes) have a skeleton that is at least partially bone. There are two subclasses/classes of Osteichthyes: Ray-finned Fishes (Actinopterygii) and Lobe-finned Fishes (Sarcopterygii). Some authorities identify Osteichthyes as a "super class" and the two subclasses as classes. Only the Ray-finned Fishes are found in North America. Ray-finned Fishes have bones supporting their fins whereas Lobe-finned Fishes have fleshy, lobbed fins.

Parts of a Boney Fish

The parts of a boney fish are shown in the diagram above. The fins of Ray-finned fishes are supported by bones and membranes called "rays." The "dorsal fin" is on the back of the fish and may have spins. The "adipose fin" is between the dorsal fin and the tail. The "pectoral fins" are on the sides of the fish behind the gills. The "pelvic fin" is on the bottom of the fish below the pectoral fin. The "anal fin" is on the bottom of the fish near the tail. The tail is also called the "caudal fin." A fish breathes by extracting dissolved oxygen from the water through the gill membranes. Generally, coldwater  fish cannot live in water that has less than five parts per million of dissolved oxygen.

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Specific Species

The following columns are specific orders of Boney Fishes of the subclass Actinopterygii found in French Hill Pond. Point and click on the photograph or common name of the species for which you wish a detailed description.

Species will be added as information becomes available.

Salmoniformes Siluriformes        
Rainbow Trout
Rainbow Trout
Brown Bullhead Catfish






     

   
     

   
     
   

 

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Fauna of French Hill Pond