What are Benthic Invertebrates?

Benthic invertebrates are spineless organisms, such as larvae, worms, and mollusks, that live on the bottom sediments, rocks, and plants of rivers, lakes, and streams. Benthic invertebrates may be fully grown, like a worm or a beetle, or they may be in their larval stages like stoneflies, mayflies, or dragonflies. They form the backbone of aquatic food chains, acting as primary and secondary consumers that process organic matter and provide food for fish. Many benthic invertebrates must be born in the water and spend most of their lives in it. When they reach their adult stage, some leave the aquatic environment and grow wings.

Mayfly larva (Order: Ephemeroptera)
Photo Credit: ECCC CABIN
Freshwater Shrimp, aka: Scud (Order: Amphipoda)
Photo Credit: ECCC CABIN
Stonefly larva (order: Plecoptera)
Photo Credit: ECCC CABIN
Dragonfly larva (Order: Odonata)
Photo Credit: ECCC CABIN

Why do we collect them?

Benthic macroinvertebrates are widely used as indicators of the biological health of waterbodies. Because they spend all or most of their lives in water, have limited mobility, and vary in their tolerance to pollution, they provide a reliable measure of environmental conditions. These organisms respond to human disturbance in predictable ways, are relatively easy to collect and identify, and often live for more than a year, making them especially useful for long-term monitoring.

Assessing the abundance and diversity of benthic macroinvertebrates offers valuable insight into the biological condition of a waterbody. Healthy aquatic ecosystems typically support a wide range of macroinvertebrate taxa, including species that are sensitive to pollution. In contrast, samples dominated by pollution-tolerant species or showing low diversity and abundance may indicate a stressed or degraded waterbody.

Stream Benthic Sampling – CABIN

The Canadian Aquatic Biomonitoring Network (CABIN) is a national program, led by Environment and Climate Change Canada (ECCC), that assesses freshwater ecosystem health using standardized sampling protocols and web-based analytical tools. Standardized sampling allows us to be able to compare results between water bodies, watersheds, and over time. 
LSWC staff are CABIN-trained and field-certified, and they follow established CABIN protocols to collect benthic macroinvertebrate samples and habitat data at stream sites throughout the watershed. This biological information complements water chemistry data, allowing for a more comprehensive understanding of stream health.
Benthic monitoring in the watershed began in 2024, with the collection of our first CABIN samples.

More about the LSWC CABIN program

Lake Benthic Sampling

Non-flowing waterbodies, such as lakes, ponds, and wetlands, are known as lentic systems. These environments typically have lower dissolved oxygen levels and support benthic invertebrate communities that differ from those found in flowing (lotic) systems.
Currently, there is limited research and available data on benthic invertebrate communities in and around Lesser Slave Lake, and no ongoing monitoring programs by government or other organizations.
To address this knowledge gap and improve our understanding of benthic invertebrates and overall lake health, the LSWC launched the Lesser Slave Lake Benthic Pilot Project in 2025.

Preliminary findings and additional information will be shared as they become available.

More about the LSWC Lake Benthic program