The Latest Field Methods to Assess Fish Populations
Electrofishing and netting
Fish Communities as Bio-indicators
Evaluating fish populations in streams and rivers has been a major component of EnviroScience’s projects since 1994. Our past experience ranges all across the mid-west, as far east as Cape Cod, Massachusetts, and as far south as Alabama. We have the capabilities to sample any size water body using electrofishing equipment, seines, hoop nets, trap nets, trawls and gill nets.
Fish communities are an excellent indicator of biological integrity due to their continuous exposure to ambient water conditions, and because they display a variety of responses to environmental disturbance, such as habitat alterations, organic enrichment, chemical toxicity, and thermal fluctuations. Therefore, they are an integral part of any bio-monitoring program.
Silver Redhorse (Moxostoma anisurum)
ES biologists have extensive experience using Ohio EPA’s Index of Biotic Integrity (IBI) and Modified Index of Well-Being (MIwb) for the assessment of biological integrity. These protocols have been instrumental in monitoring the reclamation and/or degradation of Ohio’s streams. EnviroScience has also adapted these protocols to the overlapping ecoregions in surrounding states, and uses the federal R.B.P. where needed.
EnviroScience uses the most current methodology to assess fish communities in water bodies ranging from small headwater streams to The Great Lakes, North America’s largest freshwater bodies of water. Most fish collections use pulsed DC electrical currents which temporarily stun the fish to allow for net capture. In captivity, the fish are examined for anomalies, weighed, measured for length, and quickly released unharmed. EnviroScience employs the typical electrofishing methods: backpack, long-line, tote barge, and boat.
Northern Pike (Esox lucius)
Qualitative methods can be used to supplement quantitative fish data. For example, sampling equipment can be employed to target specific species or groups of fishes. This equipment includes experimental gillnets for general species, seines for near shore species, hoopnets for bottom dwelling species, and trawls for pelagic species. Icthyoplankton sampling and identification for entrainment and impingement [316(b)] is an EnviroScience specialty. Other methods such as underwater video and sonar are also available
Data Analysis:
The ES staff has over 70 years of combined experience with fishery data analysis.
- Presence / Absence based on historical and habitat data
- Spawning
- Community Comparisons
- RIS (Representative Important Species)
- IBI (Index of Biotic Integrity) relevant in OH, KY, GA, etc.
- RBP (Rapid Bio assessment Protocol) for federal projects and state-specific (PA, WV)
- Thermal tolerance / analysis
- 316(a) and 316(b) data analysis and consulting
- Index of Well Being (IWB) and Modified Index of Well Being (MIWB)
- Catch Per Unit (CPU)
- Predation and Gut Analysis
Fishery Management
Fishery Evaluations: A Valuable Management Tool
EnviroScience biologists have extensive experience conducting full-scale fishery evaluations from small private ponds to Lake Erie. ES has sampled over 4,000 locations throughout the United States generating an exceptional knowledge base of the biology and ecology of fish communities. Three factors are needed to sustain a viable fishery in any system:
- Habitat- water quality, cover, plants, depth, substrate
- Food- invertebrates, bait fish, plankton
- Reproduction- adult survival, spawning habitat
Hoop-net deployment
An analysis of these factors in combination with abundance and diversity data is an excellent method of assessing the fishery and lake health. Fisheries are sampled using a variety of techniques including electrofishing, hoop netting, seining, gill netting, Global Positioning System technology, and Geographic Information System software. Often times, several methods are used simultaneously to ensure adequate sampling in all habitats. For example, hoop nets target bottom dwelling species sometimes missed by electrofishing.
EnviroScience personnel analyze the data to assess fish population dynamics and health, which are used to develop best management plans for stabilizing or improving the fishery. Recommendations may include stocking and habitat improvement. Our pro-active approach encourages close work and communication with the client, lake association, and other principal stakeholders. Each project is tailored to the specific needs and goals of the lake.
- Fishery evaluation – fish survey followed by a detailed report containing comprehensive data analysis, imagery generation, and management recommendations where applicable
- Nuisance species management – removal of unwanted fish species such as carp, large gizzard shad, etc.
- Fish surveys includes the collection of fish for various purposes such as tissue analysis or consumption advisories.
- Bathymetric surveys using the latest in Global Positioning Systems
- Habitat evaluation and improvement recommendations and design
- Comprehensive water quality sampling and lake diagnostics
- Qualitative and quantitative analysis or zooplankton, phytoplankton, and ichthyoplankton
ES biologist electrofishing
