Aquatic Pollution and Coastal Management

Unit 11 : Monitoring and control of pollution

11.10.1.Benthic macroinvertebrates
Advantages

• Benthic macroinvertebrates are found in most aquatic habitats.
• There are a large number of species, and different stresses produce different macroinvertebrate communities.
• Small order streams often do not support fish but do support extensive macroinvertebrate communities.
• Macroinvertebrates generally have limited mobility. Thus they are indicators of localized environmental conditions.
• Since benthic macroinvertebrates retain (bioaccumulate) toxic substances, chemical analysis will allow detection in them where levels are undetectable in the water resource.
• A biologist experienced in macroinvertebrate identification will, be able to determine relatively quickly whether the environment has been degraded by identifying changes in the benthic community structure of the water resource.
• Benthic macroinvertebrates are small enough to be easily collected and identified.
• Sampling of macroinvertebrates under a rapid assessment protocol is easy, requires few people and minimal equipment, and does not adversely affect other organisms.
• Macroinvertebrates are the primary food source for recreationally and commercially important fish. An impact on macroinvertebrates impacts the food web and designated uses of the water resource.
• State water quality agencies tend to collect macroinvertebrate data.

Disadvantages

• Benthic macroinvertebrates do not respond to all impacts.
• Seasonal variations may prevent comparisons of samples taken in different seasons.
• Drifting may bring benthic macroinvertebrates into waters in which they would not normally occur. Knowledge of drifting behavior of certain species can alleviate this disadvantage.
• Certain groups are difficult to identify to the species level.