Brook Trout Life Cycle and Habitat

Transcription

1 Brook Trout Life Cycle and Habitat

2 Directions: 1. As you watch this slide show, watch for vocabulary terms we learned today. The first time they appear, you will see them in RED! (not redd!) 2. At the end of the show, you will find definitions of all 18 terms. Check your definitions of these terms to make sure they are complete and correct! Terms: ecosystem population organism habitat biotic abiotic dissolved oxygen ph spawn redd species alevin Fry parr mark riffle run pool

3 Brook Trout Life Cycle

4 Brook Trout (Salvelinus fontinalis) Brook Trout are native to eastern Canada and much of the northeastern United States. (See map -- area with lines) RANGE They have been introduced in other parts of the continent where it is considered an invasive species, harmful to native fish. (See map -- area colored in with black.)

5 Trout, especially brook trout, are very peculiar about their habitat, having certain physical habitat requirements that must be met. Brook Trout Habitat Requirements 1) Steadily-flowing stream 2) Riffles, Runs, and Pools 3) High dissolved oxygen levels 4) Clear, Clean, Cool water 5) Bank Cover & Instream Debris 6) Gravel streambed 7) Prey species

6 Brookies prefer the relatively shallow, moving water of a stream to a lake. This means it should flow along a slight slope, but not too steep or it will flow too fast!

7 The stream should meander (curve gently) so that it forms riffles, runs, and pools. (Cobbles = small rocks or stones) Riffle

8 Pool Formation This photo shows a deep pool formed by a bend in the stream. These deep pools are an essential part of the habitat required by all stream trout. Healthy trout streams have a series of shallow riffles followed by deep pools. These pools provide trout with a place to swim and hide from predators.

9 Riffles and Dissolved Oxygen Trout, and especially brook trout, require water that is highly oxygenated. Riffles like this are well oxygenated because the surface of the water is broken so that oxygen from the atmosphere is readily absorbed.

10 Cool Water around 48 F is ideal (Water at or above 70 F can be harmful!) Trees along the stream help keep the water cool. Spring-Fed Streams are usually cool.

11 CLEAR, CLEAN WATER Brookies are less tolerant of cloudy water than are rainbow and brown trout. Clear water allows sunlight to penetrate to the streambed, promoting plant growth which provides food for the trout s prey. Clear water also makes it easier for brook trout to avoid predators, including fishermen.

12 Bank Cover Prevalent bank cover is a necessary element of every trout stream. Trout use this cover to escape predators (birds, fishermen, etc.) and to find cooler water temperatures in the areas shaded from the sun. Without bank cover, brook trout do not survive in high numbers. The removal of bank cover is a frequent problem for streams in urban or residential settings. If cover is removed and more of the stream is exposed to the sun, the water temperature will become warmer and less suitable for brook trout.

13 In-stream Debris Much like bank cover, instream debris like fallen tree branches provide trout with necessary cover. However, if there is an excess of fallen trees, the flow of the stream can become impeded. This can ultimately lead to the formation of stagnant pools with abundant algal growths, which is NOT good for brook trout..

14 Gravel bottom (streambed) (substrate) Gravel or rocky stream substrates provide ideal spawning grounds for brook trout. Trout construct spawning beds or "redds" in the gravel to deposit their eggs. The females make the redds in the autumn. After hatching, the young trout, or fry" (first they are called sac fry or alevin until they use up their yolk sac; then they are called fry when they start swimming) stay under the stones for some time before venturing out into the open water. It is important that sediment does not reach the stream in large amounts that could potentially cover the gravel streambed, which would reduce spawning area and smother newly hatched trout fry.

15 A stream that meets all these requirements will also provide an ideal habitat for the prey species eaten by the brookie: Insects and insect larvae, smaller fish, crayfish, salamanders, etc.

16 Ecology Vocabulary Terms, part 1 Habitat environment that provides things an organism needs to live, grow, & reproduce Organisms have different requirements for survival, therefore they live in different habitats Biotic (factor) Abiotic (factor) Living (or recently living) parts of a habitat E.g. grass, prairie dog, hawk, worms, fungi, dead leaves (could also be something a living thing made, like a bird s nest or beaver dam) Nonliving parts of an organism s habitat e.g., water, sunlight, oxygen, temperature, soil

17 Ecosystem The community of organisms that live in a particular area, along with all the non-living surroundings (aka both biotic and abiotic factors). Community All the different populations that live together in a particular area. Population All the members of one species that live in a particular area. Organism One individual living thing Species A group of organisms that are physically similar and can mate with each other to produce offspring that can also mate and reproduce.

18 Dissolved oxygen ph riffle run pool oxygen that is dissolved in water most organisms, including trout, require oxygen to carry out their life processes. the measure of how acidic or alkaline a solution is. ph is measured on a scale of trout need a neutral ph (7). a shallow area in the stream where it runs over stones or rocks. this adds oxygen to the water. place in the stream where it is fairly straight and has smooth, unbroken flow. area of slow-moving, deep water

19 spawn redd alevin fry parr mark to spawn is to release eggs in water. brook trout spawn in fall. the shallow depression in the gravel or on the stream bottom made by female fish, such as the brook trout, where she deposits her eggs. newly hatched baby brook trout that still have the yolk sac. can t swim; just lie on bottom and feed on their yolk sac also called sac fry once a baby trout consumes its yolk sac and it able to swim and feed on its own it is called a fry. (both singular & plural!) vertical stripes developed by fry. when it has the marks, it is often called a parr. these marks eventually fade and are not as stripey.

20 CHALLENGE: See if you can make a chart that includes the abiotic and biotic factors of the brook trout s habitat mentioned in this slide show. Brook Trout Habitat biotic factors abiotic factors