Brook Trout in ULTRA HD 4k (Salvelinus fontinalis): Under Water Spawning and Life Cycle

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• published: 28 Dec 2015
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Brook Trout (Salvelinus fontinalis) - In the last three months of the year, mature brook trout, aged 2 to 5 years, make their way to suitable spawning locations. - Brook trout seek out very specific areas to deposited their eggs. - Brook trout will key in on gravelly or sandy areas of lake bottoms, creeks, or rivers. In lakes were current is not present, brook trout will find upwelling springs that will serve to aerate the eggs. - Brook trout are a highly sensitive fish species. Only lakes, creeks, and river systems unaffected by pollution and acid rain, with high oxygen content and cool temperatures, offered by up-welling springs or current, will successfully harbour populations of brook trout. - The underwater footage of fish spawning in this video was taken in early December at the base of a long white water run. - Once the females have located suitable spawning habitat, she will use her tail fin to excavate a shallow depression called a "redd" which will serve as a nest for the eggs. - The debris that is turned up is carried downstream by the current. - The female will check the depth and thus suitability of the nest by lowering herself to the river substrate. She tests it by keeping her pelvic, anal, and caudal fins stiff, to see if they touch the bottom. - The more brightly coloured male will closely guard the female and position himself so that he can fertilize the eggs once released. The male makes various advances and passes, nudges, and comes alongside the female so that their bodies touch in order to stimulate her to release her eggs. - When the female is finally ready to deposit her eggs she will drop her anal fin deeply into the depression and then arch her back. Both the male and female will then open their mouths wide and tremble with rapid undulations of their body as the eggs and milt are simultaneously released. - As fertilization occurs externally, more than one male might fertilize the same batch of eggs. - A female may lay between 20 and 5000 eggs depending on her age, overall size, and health. She does not lay her eggs all at once, but instead releases 15 to 60 at a time. - Eggs must be fertilized within the first 3 minutes, but are most successfully fertilized immediately upon release. Fertilization success rates are often between 80 and 90 percent. - Eggs are frequently eaten by other fish species or can even be cannibalized by other males in the vicinity. Only about 1 to 2 percent of eggs will survive to adulthood. - After spawning, the female will cover the eggs by displacing sand and gravel. She does this with a slow motion sweeping of her tail to gently move gravel over the eggs without touching them. This "postnuptial dance" helps protect the eggs from predators as they develop over the next 3 months. - The female will aggressively drive off any fish that may come near the redd. - After spawning has occurred, the male will lose interest in the female and move off in search of another female building a redd. If the male is persistent, he may fertilize the eggs of multiple females. - The female, on the other hand, will move off a short distance, only to begin cutting a new redd for another batch of eggs. - After about 2 weeks, the eggs will develop eyes. The eggs absorbed oxygen from the water and feed off their yoke sack for nourishment. - At this stage, it is imperative that water remain between 1 to 13 degrees Celsius. Higher temperatures will destroy the eggs, as will sub zero temperatures. - The eggs will hatch sometime between February and March. At this point they will still feed off their yoke sac and are called fry or alevin (aləvən). - Once the yoke sac is used up, usually by March or April, the fry will begin eating plankton or microscopic animals found in the lake or stream. - By the end of the summer, the trout will be 2 to 3 inches long. As they are still quite small, they will spend much of their time hiding under and around rocks, while feeding on small insects and plankton. - Trout will reach sexual maturity when they are around 5 to 10 inches long. - The following clips demonstrate various spawning activity. You will see the female digging out a redd, while the male carefully monitors her movements in anticipation of fertilizing her eggs. You will also see males trying to move in and out compete other males for breeding rights. Enjoy! The Wooded Beardsman