Fish and Macroinvertebrates as Bioindicators in River Ecosystems

River and stream ecosystems rely on algae as the primary producer, followed by major invertebrates and fish as primary and secondary consumers.

Two major animal groups, fish and macroinvertebrates, are commonly used as bioindicators in biomonitoring purposes. Fish typically have higher trophic levels and stress tolerances, and are more mobile than macroinvertebrates, while macroinvertebrates are stationary and can represent local conditions. Both fish and macroinvertebrates are easy to sample, but fish biomonitoring tends to be more expensive. Fish are often used as bioindicators at the species level, while macroinvertebrates are used at the community level. Two examples of using fish as bioindicators are detecting heavy metal toxicity in Labeo rohita and detecting presence/absence under water quality gradients in yellowfish, catfish, and Southern mouthbrooder. These examples indicate the potential for fish to provide valuable information for biomonitoring in river and stream ecosystems.

Review questions:

• What are the primary producers in river and stream ecosystems?
• How do fish and macroinvertebrates differ in terms of trophic levels and mobility?
• Why is fish biomonitoring more expensive than macroinvertebrate biomonitoring?
• How are fish and macroinvertebrates commonly used at different scales in biomonitoring?