indicator benthic macroinvertebrate characteristics ... · citizensenvironmentwatch.org | 21...

citizensenvironmentwatch.org | 21

characteristics.

Stormwater Rainwater that runs off urban and rural areas, flows through ditches and storm drains systems, and empties into rivers and lakes untreated.

Stream Long, narrow body of flowing water occupying a stream channel and moving to lower levels under the force of gravity.

Tolerance The ability to endure the effects of particular conditions.

Tributary A stream that flows into a larger body of water.

Turbidity A term that refers to the cloudiness or murkiness of water.

Water quality A term used to describe the chemical, physical and biological characteristics of water with respect to its suitability for a particular use.

Watershed Land area from which water drains to a particular surface water body.

Wetted width The length of the line of contact between the water of a stream and its(Active Channel) channel.

INDICATOR BENTHIC MACROINVERTEBRATE SPECIES AND THEIR CHARACTERISTICS

Benthic Macroinvertebrate Identification Sheets, Citizens’ Environment Watch Water Quality Monitoring with Benthic Macroinvertebrates, 2005

Coelenterata(Hydras)

ADULT

A tube with tentacles

Reproduces asexually by budding

Movement: sessile, attached or fixed, not free moving

Colour: clear to whitish

Size: 2 to 25 mm

Turbellaria(Flatworms)

ADULT

Flattened shape

Distinct head with eye spots

Movement: creeps slowly along tray bottom

Colour: usually dark, mottled greyish-brown to black

Size: 5 to 30 mm

Tolerance Value: 8

Nematoda(Roundworms)

ADULT

Tapered head

Pointed tail

Non-segmented

Movement: rapid, whip-like

Colour: often clear

Size: 5 to 15 mm

Oligochaeta(Aquatic Earthworms)

ADULT

Segmented, round, soft bodies, similar to earthworms

Tiny bundles of hairs on each segment behind the first

Movement: crawls along the tray bottom, or curls up

Colour: often pinkish or brown

Size: 1 to 30 mm

Tolerance Value: 8

22 | WATER QUALITY Monitoring with Benthic Macroinvertebrates

Hirudinea(Leeches)

ADULT

Body with 34 annulated seg-ments, suckers on both ends

Head often with several pairs of eyes

Movement: uses suckers to inch along tray bottom, or swims

Colour: varies, often patterned

Size: 5 to 300 mm

Tolerance Value: 8

Isopoda(Sow Bugs)

ADULT

7 pairs of legs

Dorso-ventrally compressed

1st antennae longer than 2nd

Movement: crawls along tray bottom

Colour: greyish

Size: 5 to 20 mm

Tolerance Value: 8

Pelecypoda(Clams)

ADULT

Hard oval shell hinged in two halves

Do not count empty shells

Movement: none

Colour: varies

Size: 2 to 250 mm

Tolerance Value: 6

Amphipoda(Scuds)

ADULT

Six pairs of legs

Laterally compressed

Two pairs equal length antennae

Movement: swims on its side

Colour: often light grey or brown

Size: 5 to 20 mm

Tolerance Value: 6




Decapoda(Crayfish)

ADULT

Large claws; eyes on stalks

Looks like small lobster

Movement: swims backwards

Colour: green, brown, or blue

Size: 10 to 150 mm

Tolerance Value: 5

Trombidiformes-Hydracarina(Mites)

ADULT

Eight legs, like small spiders

Round body

Movement: uncoordinated scrambling, swimming

Colour: brightly colouredeg. red, green

Size: 0.5 to 7 mm

Tolerance Value: 6

Ephemeroptera(Mayflies)

NYMPH

Single tarsal claw

Gills under abdomen

Usually three tail filaments

Movement: swims up and down in an “S” pattern

Colour: brown

Size: 3 to 28 mm (not incl. tail)

Tolerance Value: 5

Anisoptera(Dragonflies)

NYMPH

Big head and eyes

No external gills

Modified labium for catching prey

Movement: slow

Colour: drab, brownish, green

Size: 15 to 45 mm

Tolerance Value: 5




Zygoptera(Damselflies)

NYMPH

Compound eyes

Tubular, thin body

Three gills at terminus of abdomen

Movement: slow

Colour: drab

Size: 10 to 25 mm

Tolerance Value: 7

Plecoptera(Stoneflies)

NYMPH

Tarsi with two claws

No gills on abdomen

Two tail filaments

Movement: swims, walks slow

Colour: drab, varies

Size: 5 to 50 mm

Tolerance Value: 1

Hemiptera(True Bugs)

ADULT

Three pairs of soft, folded wings

Soft body

Movement: swims, skims water surface

Colour: black to brownish

Size: 15 to 40 mm

Tolerance Value: 5

Megaloptera(Fishflies, Alderflies)

LARVAE

Well developed mandibles

Lateral abdominal gill filaments

Three pairs of legs

Movement: crawls

Colour: drab, brown

Size: 25 to 90 mm

Tolerance Value: 4




Trichoptera(Caddisfl ies)

LARVAE

Often found in cases (do not count empty cases)

Dorsal thorasic plates sclerotized

Anal prolegs with hooks

Movement: slowly crawls

Colour: cream coloured abdomen

Size: 2 to 50 mm

Tolerance Value: 4

Lepidoptera(Aquatic Moths)

LARVAE

Head with ring of ocelli

Th ree pairs of short, segmented, thoracic legs

Ventral, abdominal prolegs

Movement: crawls like a caterpillar

Colour: varies

Size: 10 to 25 mm

Coleoptera(Beetles)

ADULT & LARVAE

Th ree pairs of segmented legs

Hardened forewings

Larvae with sclerotized head with mandibles

Movement: crawls, swims

Colour: black, brown

Size: 2 to 40 mm

Tolerance Value: 4

Gastropoda(Snails, Limpets)

ADULT

Hard spiral or cap-shaped shell

Do not count empty shells

Movement: none

Colour: varies

Size: 2 to 70 mm

Tolerance Value: 8


Benthic Macroinvertebrate Identifi cation Sheets, Citizens’ Environment Watch Water Quality Monitoring with Benthic Macroinvertebrates, 2005


Chironomidae(Midges)

LARVAE

Sometimes in tube of silt, segmented body

Characteristic “J” shape

Anterior and posterior parapods

Movement: whip-like motion

Colour: varies - red, white, yellow

Size: 2 to 30 mm

Tolerance Value: 7

Tabanidae(Horse and Deer Flies)

LARVAE

Pointed at both ends, segmented

Leathery texture

Several pairs of creeping welts with hooks on each segment

Movement: none

Colour: white, cream

Size: 15 to 40 mm

Tolerance Value: 5

Culicidae(Mosquitos)

LARVAE

Fused thoracic segments

Posterior respiratory siphon

Movement: twitches when touched

Colour: brown

Size: 3 to 15 mm

Tolerance Value: 5

Ceratopogonidae(No-see-ums)

LARVAE

Very slender, pointed at both ends

Segmented with sclerotized head

Movement: whips, stiffens when touched

Colour: varies

Size: 3 to 13 mm




Tipulidae(Crane Flies)

LARVAE

Reduced head is retracted into thorax

Posterior respiratory disc with lobes

Movement: worm-like

Colour: white, yellow, brown

Size: 10 to 50 mm

Tolerance Value: 3

Simuliidae(Black Flies)

LARVAE

Often with pair of labral fans

Fattened posterior with attachment organ

Movement: like an inch-worm

Colour: greyish, brown

Size: 3 to 15 mm

Tolerance Value: 6

Misc. Diptera(Misc. True Flies)

LARVAE

Adults with single pair of wings

No jointed thoracic legs

May have parapods, pseudopodia, creeping welts, appendages

Movement: varies

Colour: varies

Size: varies

CREDITSImages and characteristics adapted from Gartner Lee Limited, 1997; Ontario Benthos Biomonitoring Net-work, 2005.

Tolerance values indicate tolerance to nutrient enrich-ment (Southern Ontario). Values are between 0 (intoler-ant) and 10 (very tolerant).

Tolerance values adapted from Watershed Report Card, 2000.



indicator benthic macroinvertebrate characteristics ... · citizensenvironmentwatch.org | 21...

Documents