Monday, March 17, 2014

Wildlife Quiz - Rainbow Trout

Rainbow (bottom), Brook Trout (Top)
Rainbow Trout
Because of their natural ability to thrive in hatcheries, Rainbow Trout (Oncorhynchus mykiss) or simply “Rainbows”, have been introduced across most of the United States and inhabit many streams and lakes throughout the state of Maine. Though an introduced species, many anglers enjoy catching this transplant for food and sport despite its ability to over compete many native fish species. Maine anglers normally catch stream dwelling rainbows in the 8 to 16-inch range; with occasional lake caught fish reaching upwards of 5-6 pounds.

*The current state of Maine record rainbow was 6.52 pounds pulled out of the Androscoggin River by Steven Day in 2007. 

Rainbows posses’ silvery colored sides and a white to pale yellow belly color with a prominent reddish colored band, extending from the cheek to the base of the caudal fin. A sizeable numbers of small black dots cover the entire body with heavier spotting generally occurring along dorsal areas. Rainbow coloration can be highly variable, depending on size, sexual condition, and habitat.

Rainbows are opportunistic feeders, relying on a variety of food items for sustenance, ranging from insects to crustaceans. Rainbows inhabiting streams tend to feed heavily on terrestrial insects, such as grasshoppers, ants and aquatic insects. In lakes, rainbows feed primarily on crayfish, snails, small fish and fish eggs.

Rainbows spawn in the spring and early summer. Female rainbows dig depressions in the gravel with their tails, into which eggs are deposited. A male fertilizes the eggs, covers them with gravel and leaves them to incubate and hatch. After hatching, young rainbows swim free of the gravel and begin searching for food. With luck, stream dwelling fry will avoid predators, grow-up and live almost 3 years while those living in larger bodies of water, such as lakes and ponds tend to live 5-6 years. The oldest recorded specimen of rainbow reached a ripe old age of 11 years.

Wildlife Quiz Questions 
1. Are rainbow trout an introduced species in the state of Maine?
2. What is the average weight of a stream caught rainbow trout in Maine?
3. What was the weight of the largest rainbow trout caught in the state of Maine?
4. What is a prominent feature of the rainbow trout that easily distinguishes it from other species of salmonids?
5. What do rainbow trout eat?
6. When do rainbow trout spawn?
7. How old do most lake and pond dwelling rainbow trout live?
8. What was the age of the oldest rainbow trout?

Wildlife Quiz Answers 
1. Yes, rainbow trout are an introduced species in the state of Maine.
2. The average weight of a rainbow trout caught in Maine is between 8-16 inches.
3. The largest rainbow trout caught in the state of Maine was 6.52 pounds.
4. Rainbow trout are easily distinguished from other salmonids by a reddish colored band, extending from the cheek to the base of the caudal fin.
5. Rainbow trout are opportunistic feeders and eat everything from grasshoppers and ants to small fish, fish eggs, crayfish and snails.
6. Rainbow trout spawn in the spring and early summer.
7. Most rainbow trout inhabiting lakes and ponds live to be between 5-6 years.
8. The oldest rainbow trout lived to be 11 years old.

1 comment:

  1. First off, thanks Steve for posting this -- a good summary. If you intended the quiz to include a trick question, it worked. I was stumped by No. 2, and had to chuckle when I gave up and looked at the answer! At least that might let you know whether someone read it through.


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