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Aquatic macroinvertebrates as indicators of water quality

Macroinvertebrates are good indicators of biological quality, as they are easy to sample and require only relatively simple taxonomic identification. They are also widespread in most areas where water is present.

These creatures are used as quality indicators in the majority of rivers in the world, as they respond to environmental changes in a very direct manner and they facilitate the assessment of any disturbances or modifications in rivers and wetland areas.

If water quality is good, there are a lot of species, however, if it is bad, there may be a lot of individual animals, but only a few species.

Qualitat bona

Qualitat Intermèdia

Qualitat dolenta

Aquatic macroinvertebrates

Aquatic macroinvertebrates are large animals (over 500 micrometres and without an internal skeleton) that live in continental aquatic ecosystems (rivers, ponds, lakes and estuaries, etc.).

They are distributed throughout different environments in bodies of water: under stones, in calm waters, in rapids, and waterfalls, among underwater plant life, etc.

They include aquatic and semi-aquatic organisms as well. One example of semi-aquatic organisms are heteropterae – more commonly known as pond skaters; these creatures walk, slide and jump on the water’s surface. There are in fact very few macroinvertebrates that are truly aquatic throughout their entire lives, such as sponges, molluscs and crabs.

Most, especially insects, caddis-fly larvae and dragonflies, live in the water only during their larval or nymphal phase.

cicle
cicle
cicle

Planaria

	Common flatworm

Common flatworm
Dugesiidae

Worms

	Earthworm

Earthworm
Lumbricidae

Arachnids

	Water mite

Water mite
Hydracarina

Bloodsuckers

	Leech

Leech
Erpobdellidae

 

	Freshwater jawless leech

Freshwater jawless leech
Glosiphoniidae


Molluscs

	Ancylini

Ancylini
Ancylidae

	Pond snail

Pond snail
Lymnaeidae

	Bladder snail

Bladder snail
Physidae

	Ramshorn snail

Ramshorn snail
Planorbidae

	Freshwater mussel

Freshwater mussel
Unionidae

Crustaceans

	Water flea

Water flea
Cladocera

	Copepod

Copepod
Copepoda

	Ostracod or seed shrimp

Ostracod or seed shrimp
Ostracoda

	Assassin fly

Assassin fly
Aseliidae

	Freshwater crayfish

Freshwater crayfish
Astacidae

Insects

Ephemeroptera

	Small mayfly

Small mayfly
Baetidae

	Small squaregill mayfly

Small squaregill mayfly
Caenidae

	Prong-gilled mayflies

Prong-gilled mayflies
Leptophlebiidae

	Stream mayfly

Stream mayfly
Heptageniidae

Heteroptera

	Backswimmer

Backswimmer
Notonectidae

	Lesser water boatman

Lesser water boatman
Corixidae

	Water scorpion

Water scorpion
Nepidae

	Marsh treaders

Marsh treaders
Hydrometridae

	Pond skater

Pond skater
Gerridae

Dragonflies

	Aeshnid

Aeshnid
Aeshnidae

	Club-tail dragonfly

Club-tail dragonfly
Gomphidae

	Skimmer or percher

Skimmer or percher
Libellulidae

	Broad-winged damselfly

Broad-winged damselfly
Calopterygidae

	Spreadwing

Spreadwing
Lestidae

Beetles

	Predaceous diving beetle

Predaceous diving beetle
Dytiscidae

	Water-scavenger beetle

Water-scavenger beetle
Hydrophilidae

	Haliplid

Haliplid
Haliplidae

	Riffle beetle

Riffle beetle
Elmidae

	Whirligig beetle

Whirligig beetle
Gyrinidae

	Long-toed water beetle

Long-toed water beetle
Dryopidae

Plecoptera

	Spring stonefly

Spring stonefly
Nemouridae

	Needlefly

Needlefly
Leuctridae

	Stonefly

Stonefly
Perlidae

	Springfly

Springfly
Perlodidae

Trichoptera

	Caddis fly

Caddis fly
Limnephilidae

	Long-horned caddis fly

Long-horned caddis fly
Leptoceridae

	Net-spinning caddis fly

Net-spinning caddis fly
Hydropsychidae

	Free-living caddis fly

Free-living caddis fly
Rhyacofilidae

	Finger-net caddis fly

Finger-net caddis fly
Philopotamidae

Diptera

	Lake fly

Lake fly
Chironomidae

	Black fly

Black fly
Simuliidae

	Mosquito

Mosquito
Culicidae

	Crane fly

Crane fly
Tipulidae

	Hoverfly

Hoverfly
Syrphidae

Illustrations: © Toni Llobet