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
INDICATOR BENTHIC MACROINVERTEBRATE SPECIES AND THEIR CHARACTERISTICS
Benthic Macroinvertebrate Identification Sheets, Citizens’ Environment Watch Water Quality Monitoring with Benthic Macroinvertebrates, 2005
citizensenvironmentwatch.org | 23
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
INDICATOR BENTHIC MACROINVERTEBRATE SPECIES AND THEIR CHARACTERISTICS
Benthic Macroinvertebrate Identification Sheets, Citizens’ Environment Watch Water Quality Monitoring with Benthic Macroinvertebrates, 2005
24 | WATER QUALITY Monitoring with Benthic Macroinvertebrates
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
INDICATOR BENTHIC MACROINVERTEBRATE SPECIES AND THEIR CHARACTERISTICS
Benthic Macroinvertebrate Identification Sheets, Citizens’ Environment Watch Water Quality Monitoring with Benthic Macroinvertebrates, 2005
citizensenvironmentwatch.org | 25
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
INDICATOR BENTHIC MACROINVERTEBRATE SPECIES AND THEIR CHARACTERISTICS
Benthic Macroinvertebrate Identifi cation Sheets, Citizens’ Environment Watch Water Quality Monitoring with Benthic Macroinvertebrates, 2005
26 | WATER QUALITY Monitoring with Benthic Macroinvertebrates
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
INDICATOR BENTHIC MACROINVERTEBRATE SPECIES AND THEIR CHARACTERISTICS
Benthic Macroinvertebrate Identification Sheets, Citizens’ Environment Watch Water Quality Monitoring with Benthic Macroinvertebrates, 2005
citizensenvironmentwatch.org | 27
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 SPECIES AND THEIR CHARACTERISTICS
Benthic Macroinvertebrate Identification Sheets, Citizens’ Environment Watch Water Quality Monitoring with Benthic Macroinvertebrates, 2005