aquatic invertebrates

Aquatic Invertebrates

• Insects: mayflies; caddis; stoneflies; midges; damsel flies; dragonflies, & water boatman.

• Bloodworms: midge larvae & tubiflex worms

• Leeches

• Scuds

• Snails

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Flies to Imitate Trout Foods

• Movement: Retrieve to mimic the actual;

• Size: Use hook sizes and shapes;

• Color: Use materials to match the color;

• Shape: Use hook shape and tying materials to match profiles.

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MayfliesOrder: Ephemeroptera

Mayflies comprise 20 to 80 percent of a trout’s diet. There are over 700 species in North America.

They emerge from the water surface. Adult duns and spinners have upright wings.

This is an adult Pale Morning Dun.

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Mayfly Adults

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Mayflies: Distinguishing Characteristics

• Nymph: Most have three tails; others have two

• Nymph: Gills are along abdomen

• Nymph: One wing pad

• Emerger: Most “hatch” in water surface film

• Adult: Sail-like upright wings

• Habitat: Most species in streams; Nymph body-type/behavior indicates habitat-type.

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Mayflies: Behavioral Characteristics

• Nymph: Modes of Movement --- Swimmers, Clingers, Crawlers, & Burrowers

• Emerger: Duns fly straight upward from the water surface

• Adult: After laying eggs, spinners lay on the water surface with spent (out to the side) wings.

• Habitat: Most species in streams; Nymph body-type/behavior can indicate habitat-type.

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Mayflies: clingers

Green Drake nymphs, Drunella grandis and Ephemerella doddsi, and fast water, clinging body type with imitation Hare’s Ear nymph.

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Mayflies: swimmers

Blue Wing Olive adult and nymph with imitation BWO parachute dry fly and pheasant tail nymph

Most have three tails and one wing pad.

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Mayflies: swimmers

Pale Morning Dun nymph with Pheasant Tail and Polyback PMD wet flies

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Mayflies: swimmers

Genus: Leptophlebia and SiphlonuidaeGills are along the side of abdomen.One wing pad is common.

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Mayflies: crawlers

Genus: Epeorus and Stenonema

Epeorus has only two tails.

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Mayflies: burrowers

Genus: Hexagenia, nymph and adult

One of the few mayflies that can live in lakes.

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Caddis flies or SedgesOrder: Trichoptera

There are 1,200 species in North America.

They emerge on the water surface.

Spotted sedge adult and Elk Hair Caddis fly: match color, body shape, legs, and antennae.

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Caddis flies or SedgesDistinguishing Characteristics

• Nymph: Worm-like body usually inside a case

• Nymph: Gills along the abdomen

• Adult: Long antennae

• Adult: Wings are covered with fine hairs

• Adult: Wings make a “tent” shape over the body

• Habitat: A wide range of streams & stillwaters

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Caddis flies or SedgesBehavioral Characteristics

• Nymph: Crawl on stream / lake bottom

• Pupae: Leave case to emerge

• Pupae: Most swim rapidly to the water surface to emerge; some swim to shore / vegetation

• Adult: Fly at an angle from the water surface

• Adult: Fly in a fluttering manner

• Habitat: A wide range of streams & stillwaters

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Caddis flies

Adult wings form a “tent” and are covered with fine hairs.

Imitations: X-Wing Caddis and Elk Wing Caddis

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Caddis flies

Caddis pupa, Hydropsychidae, and imitation emerger

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Caddis flies

Free living October caddis larva and portable case larvae with imitation wet flies.

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StonefliesOrder: Plecoptera

There are 500 species in North America.

The adult wings fold over their body when at rest.

Adults emerge after the nymphs crawl out of the water onto shoreline rocks and vegetation.

StimulatorSalmonfly

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Stoneflies: Distinguishing Characteristics

• Nymph: Gills at the base of legs• Nymph: Two or three wing pads; Two tails• Emerger: Exoskeleton dries and cracks

down the back (dorsal side)• Adult: One to three inches long; wings

that fold flat over body at rest; a bi-plane flight pattern; females are larger

• Habitat: Cold, fast-moving sections of streams with rocky bottoms

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Stoneflies: Behavioral Characteristics

• Nymph: Crawl along the stream bottom

• Nymph: Most are predators

• Emerger: Crawl to shore & vegetation

• Emerger: Water temperature dependent

• Adult: After mating, females lay eggs on water surface.

• Habitat: Cold, fast-moving sections of streams with rocky bottoms

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Stoneflies:Skwala stones & flies

Most widespread stonefly species in North America.

Usually emerge from mid-March to mid-April.

Black to dark olive on top of body and a dirty yellow color underneath.

Skwala adult & fly

Skwala nymph Skwalafly

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Stoneflies

Nymph require clean, highly oxygenated water.

Nymphs and adults have two tails and antennae.

Nymphs have two or three wing pads.

Kaufmann’s stone

Bitch Creek nymph

Prince nymph

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Stoneflies: salmon flies

Nymph emergence and adult reproduction occurs in a few days to weeks. Trout gorge themselves in this brief time period.

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True fliesOrder: Diptera

Di (two) and ptera (wings) are true flies. There are 3,500 species in North America.

These include flies, mosquitoes, crane flies, midges, and gnats.

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True flies:Distinguishing Characteristics

• Nymph: Worm or maggot-like bodies; chironomids

• Nymph: Most non-mobile with false legs

• Emerger: Gases build-up in body & allow it to float to the surface; water surface film

• Adult: One pair of wings

• Habitat: Mud or silt stream and lake bottoms

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Chironomid Pupa

Larval forms or chironomids slowly float to the water surface to emerge using gases that gradually build in the exoskeleton as they pupate. Fly fishing at the proper depth and with very slow movement is critical to success.

Midge Hatch

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Midge Hatch

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Midge flies

Chironomid pupa can emerge or “hatch” into midge flies all year, mainly when the surface water temps are between 42 and 56 deg. F.

Midge flies

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Bloodworms• This is a chironomid (midge) insect larvae.

• It lives on the muddy lake or stream bottom where the oxygen levels are low.

• It feeds on detritus & bacteria.

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Bloodworms

• This is a tubiflex worm, a true worm.

• Like the midge larvae they have a reddish blood similar to hemoglobin.

• This is the adult form.

• They live on the muddy lake or

stream bottom & feed on detritus.

• They are used by aquarium

enthusiasts for fish food. 33

Bloodworms

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Bloodworms & Flies

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Damsel fliesSuborders: Odonata and Zygoptera

The nymphs are voracious predators that crawl to aquatic vegetation to emerge as adults. Nymphs and adults live in the slow margins of streams.

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Damsel flies

Nymphs have long, slender bodies and three paddle-like gills at the end of the abdomen. Most nymphs are olive or tan and most adult males are blue and black.

DragonfliesSuborder: Odonata

• Nymphs or naiads spend 2 years in water.

• Can rotate head almost 360 degrees.

• Has very large compound eyes.

• Lacks a pupae (no emerger) life stage.38

Dragonfly Nymphs & Flies

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Water Boatman

• Aquatic insects of certain ponds & lakes.

• Have two oar-like legs.

• Males & females congregate at a lake to mate & lay eggs causing a fish feeding frenzy.

• Females trap air bubbles to go to the lake bottom and lay eggs. (1st half September)

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Freshwater Leeches

• Segmented worms with 5 pairs of eyes.

• Two suckers; one at each end.

• Can be 2 to 3 inches long.

• Swim in an undulating up & down motion.41

Leeches

• They are brown, olive, black, & maroon.

• Majority of leeches are NOT blood sucking.

• 650 species

• Lay eggs in a “cacoon” case on the bottom of lake or stream.

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Leech Flies

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Scuds

• These freshwater “shrimp” have a chitinous exoskeleton & require water with high levels of calcium.

• Both thorax & abdomen have legs.

• Females have a brood pouch.

• Habitat is aquatic plants in shallow shoals (littoral zone).

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Scuds

• Body color matches habitat & food supply from light olive to olive, tan, and brown.

• They have two sets of antennae.45

Scud Flies

• Only use this fly when you know the lake or stream has scuds.

• Tie this wet fly with internal weight.

• Fish it at the deep side of its habitat.

• Fish it with a loop knot under a strike indicator & floating fly line or with a slow retrieve and sinking fly line.

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Freshwater Snails

• Have soft bodies covered by hard shell.

• Have one large foot.

• Have two tentacles with an eye on each.

• Live in ponds, lakes, and slow streams.

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Freshwater Snails

• Fish usually feed on snails when other food sources are limited; i.e. winter.

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Snail Flies

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Terrestrial Insects & FliesTerrestrial Insects & Flies

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Grasshoppers and CricketsGrasshoppers and Crickets


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BeetlesBeetles


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Ants and TermitesAnts and Termites


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SpidersSpiders


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Butterflies and MothsButterflies and Moths

aquatic invertebrates

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