Monitoring supports effective resource management by:

  • describing the distribution and diversity of aquatic resources
  • reporting on the status of aquatic resources and how they are changing over time
  • measuring success of management actions and policies
  • understanding the impacts of large scale disturbance and human activities on aquatic resources
  • describing who is using resources, their patterns and changes in attitudes toward management

Monitoring needs to follow a standard approach to:

  • detect changes in the status of the resource over time
  • compare survey results between water bodies

Guidelines for monitoring lakes

Broad-scale fish community monitoring

This is the provincial standard for monitoring fish communities in Ontario lakes. It replaces the aquatic habitat inventory for acquiring basic knowledge of fish communities.

It uses a combination of 2 types of gillnets:

  • large-mesh gillnets that target fish longer than 20 cm to sample angle-harvested freshwater fish
  • small-mesh gillnets that target smaller fish

This manual provides guidelines for:

  • measuring secchi depth
  • taking temperature/oxygen profiles
  • conducting reconnaissance for aquatic invasive species
  • processing fish
  • taking contaminant samples for fish captured in Ontario lakes

Aquatic habitat inventory survey

Aquatic habitat inventory surveys measure the basic chemical, physical and biological conditions of Ontario lakes, rivers and streams. The survey inventoried more than 10,000 Ontario lakes and streams from 1970 – 1990. Unfortunately:

  • many of the methods described are now outdated
  • the manual is no longer widely used

Use the AHI protocols unless there are newer protocols for basic inventorying of lakes and streams.

Download the guidelines for aquatic habitat inventory surveys (PDF)

Bathymetric surveys

Bathymetric surveys map the physical characteristics of a waterbody. The data can:

  • construct a map showing depth contours and the underwater structure
  • calculate the volume, mean and maximum depths of a waterbody

This manual:

  • describes the hardware and field procedures for collecting bathymetric data with the BASS system (Bathymetric Automated Survey System)
  • explains how to process the data in GIS (Geographic Information Systems) to produce maps for fisheries management

Download the guidelines for bathymetric surveys (PDF)

Brook trout index netting

The standard methods and technical information for conducting the brook trout index netting field program. The program:

  • makes an unbiased count of brook trout
  • collects biological information

End of spring trap netting

An adaptation of the nearshore community index netting protocol. This live-release trap netting program assesses the status of Ontario walleye by:

  • estimating their relative abundance
  • gathering biological data

Fall walleye index netting

Collects biological information used to manage percid fisheries dominated by walleye. The index:

  • uses overnight sets of multi-mesh gillnets
  • is used in waterbodies where lethal sampling is acceptable

Download the guidelines for fall walleye index netting (PDF)

Nordic netting

An international standard gillnetting procedure used in many Scandinavian countries. The method:

  • samples fish with multi-mesh gillnets
  • provides a whole-lake estimate for species occurrence, quantitative relative abundance and biomass

Nearshore community index netting

A live-release trap netting program that assesses fish communities in the nearshore zone of Ontario lakes.

Spring littoral index netting

Collects information about lake trout populations by sampling a lake’s nearshore zone in spring. This method:

  • surveys abundance and biological data
  • uses 90-minute gillnet sets
  • minimizes mortality with short net sets

Summer profundal index netting

Collects abundance and biological information for adult lake trout. This rapid assessment method:

  • requires less than a week to complete
  • offers a lower mortality option for sensitive populations
  • allows many lakes to be surveyed in a single season

Guidelines for monitoring rivers

Basal resources sampling

Methods for sampling the basal energy resources that support a river’s fish species and ecosystem. These include:

  • aquatic macrophytes
  • periphyton
  • organic material and woody debris

Benthic sampling in natural and regulated rivers

Methods for sampling riverbed invertebrates that consider the effects of river currents and hydropower.

Electrofishing rivers: nearshore community sampling methodologies for flowing waters

An adaptation of standard methods for sampling the wadeable nearshore fish community in non-wadeable rivers using electrofishing gear.

Measuring stream temperature using data loggers: Laboratory and field techniques

Methods for measuring water temperature in flowing waters, with instructions on:

  • choosing a temperature data logger
  • laboratory procedures
  • field procedures
  • retrieving and handling time-series temperature data
  • using ThermoStat to analyze and report field measurements

Ontario stream assessment protocol – 2010 update

Standardized stream assessment techniques for evaluating habitat, benthic invertebrate and fish communities in Ontario’s wadeable streams.

Download this guideline (PDF)

Riverine index netting

The provincial standard for assessing fish populations and communities in medium to large non-wadeable rivers. The guide provides:

  • gear description
  • field procedures
  • pre- and post-field activities
  • data management
  • a hypothetical case study for a hydropower development
  • appendices on bathymetry mapping, aging structures, contaminant analysis, field forms, equipment list and fish species codes

Download the guideline for riverine index netting (PDF)