Fisheries Management Glossary


Below is a listing of common terms relating to fisheries management in Alberta.


Active Management

A term applied to fisheries which are relatively well-studied, for which the management is data-based, as a result of regularly completed surveys.

Adaptive Management

Adaptive management formulates management policies as experiments that probe the responses of ecosystems as people’s actions in them changes. The aim is to learn something about the processes and structures of the ecosystems; one seeks to design better policies and to contrive better experiments.

Adaptive Management and Experimentation

Adaptive management and experimentation have and continue to be a part of furthering fisheries science.  The level of risk to the population can vary widely depending on the type of study.  Often we call these ‘pilot’ regulations.


In Alberta, the allocation and use of fisheries are shared amongst several user groups and their uses. In priority, 1) Conservation, 2) Indigenous use, 3) Recreational use, and 4) Competitive use.


Biological diversity in an environment as indicated by numbers of different species of plants and animals.

Carrying capacity (K)

The number of individuals an environment can support without significant negative impacts to the organism and its environment.


The measure of fishing mortality on a stock by a unit of fishing effort. In fisheries, catchability (q) relates catch per unit effort (x) to stock size (N) or x = q (N).

Cumulative effects model

A cumulative effects model is used to identify the principle threats amongst a larger set of known or assumed threats to an organism of ecological system on  the landscape (for example in a watershed) and calculate expected improvements in population status if the effects of these threats are reduced.


A system of living and nonliving things interacting under natural conditions.

Experimental management objective

This category of objective designates a situation in which an adaptive management study is designed to provide fisheries managers the opportunity to rigorously test the performance of one or more management actions and incorporate those results into management plans.

Exploitation harvest

The use of natural resources for human use. Overexploitation or over harvest is the over use or removal of resources to the level that cannot sustain viable populations.

Fall Index Netting (FIN) stock assessment

Fall index netting is used by Alberta Environment and Parks to primarily monitor Walleye and Northern Pike populations. Standardized multi-mesh gill nets are set at random locations between 2 and 15 metres deep, set overnight, and then reset in new random locations the next day.

Fish Conservation and Management Strategy (FCMS)

This is a strategy that provides guidance to the management of fisheries in Alberta. Key benefits are sustainable management of fisheries for Alberta’s Indigenous peoples, as well as for the socially and economically valuable recreational fisheries.

Fish Sustainability Index (FSI)

The FSI is Alberta’s method of assessing fish stocks on a provincial scale, developed to bring consistency to stock assessments and provide a province-wide evaluation of the sustainability of Alberta’s fish stocks over time.

Fisheries Management Objectives

The most basic planning tool. FMOs consist of objectives in four aspects of fisheries use and management (recreational, indigenous, habitat and ecosystem).  FMOs convey and link current fishery status, to desired outcomes via management direction and approach, identifying the challenges or limitations to achieving the objective.

Fishery Management Framework

In Alberta, Fishery Management Frameworks describe the context for understanding the management approach taken for a species. It consists of a specific and consistent set of sportfishing regulations and actions designed to achieve management objectives.

Fishing effort

The amount of fishing or angling usually measured in hours and is standardized to the area of a waterbody (i.e., number of angling hours per lake hectare). This is sometimes described as “fishing pressure”.

Growth overfished

The rate of harvest when large fish are over-proportionally removed from the stock. Since older and larger fish are better able to buffer mortality and poor environmental conditions, this truncation of the fish stock’s age-structure can lead to magnified fluctuations of abundance.
Growth overfishing, by itself, may not affect the ability of a fish stock to be sustainable.

High Risk Fisheries

A fishery has been assessed and is classified as “high risk” to long term sustainability based upon the adult density of fish in the lake. It would receive a recovery regulation as it could not sustain an open harvest (in other words a minimum size limit would still be too high of risk to the recovery of the fishery).

Hydrological Unit Code (HUC)

A numeric system for identifying nested watershed units, which has been adopted by Alberta to assist with assessing and managing resources.

Index of abundance

The relationship between the amount of fish in a water body and the catch rate of a sampling method (i.e., Fall Index Netting).

International Union for Conservation of Nature (IUCN)

Created in 1948, IUCN has evolved into the world’s largest and most diverse environmental network. It harnesses the experience, resources and reach of its 1,300 Member organisations and the input of some 16,000 experts. IUCN is the global authority on the status of the natural world and the measures needed to safeguard it.

Liberal harvest fishery

This management objective provides anglers with fish to harvest, with few restrictions.

Management of Remote Lakes

Remote lakes typically receive low to moderate levels of fishing pressure.  These lakes are also challenging to monitor due to their relative inaccessibility.  Often fishing pressure is a very minor influence on the population status at these lakes. 

Maximum sustainable yield (MSY)

Theoretical harvest of a fish species that can be taken over an indefinite period. MSY theoretically aims to maintain the population size at the point of maximum growth rate by harvesting the individuals that would normally be added to the population. MSY has been widely criticized and has led to the collapse of many fisheries, as it ignores size, age, reproductive capacity, and fishing effort.

Old growth fishery

Maintenance of a ‘high value’ fishery characterized by a relatively high abundance of large or uncommon fish.  This management objective provides anglers with a ‘blue ribbon’ opportunity to catch trophy sized fish or a native fish species that is scarce to anglers (for example Lake Sturgeon). Harvest opportunities for old growth fisheries are extremely limited or unavailable.

Open-access management

Unrestricted access to a fishery. Open access in Alberta refers to utilizing fishing regulations that manage the harvest of fish with size and bag limits, and seasonal closures. The number of people that come to a fishery is not managed.

Open Harvest Seasons

Short, open harvest seasons for waterbodies are another way to allow some harvest, that typically employ minimum size limits as precautionary measures against over harvest.

Optimum sustainable yield (OSY)

The theoretical balance between current production and mortality without decreasing the capacity of the stock or its ecology.

Passive management

Information from well understood systems is combined with traditional, local and non-fishery specific data to assess populations and inform management actions at less studied waterbodies.

Population status

A population’s status is assessed using variables that are important aspects of the population and management (for example adult abundance, threats, and limitations). Current status is compared to the desired status that is based on constraints and stakeholder input. Differences between the current and desired status trigger implementation of a management action.

Precautionary approach

A management approach which is based on the acceptance of uncertainty and developing defensible, repeatable means of making management decisions using the best available information. It is imperative to avoid management paralysis which can also lead to the decline, collapse, or loss of fish stocks. The precautionary principle is recognized globally as a fundamental concept of sound biological resource management.

Preservation Management Objective

This category of Fisheries Management Objective is applied to stocks that are self-sustaining stocks with naturally-low abundance. These unique stocks may be characterized by genetically distinct, unusual life history, or are naturally limited.

Production (kg of fish/ha)

Rate of generation of biomass of a fish species in a waterbody; usually expressed in kilograms per hectare. It is dependent on the stock status of the species in a particular system; a collapsed stock has less production than a stable fishery.

Quality Harvest Fishery

This category of harvest fishery is characterized by relatively increased abundance of large, older fish which provides anglers with the opportunity to catch and occasionally keep a memorable fish.


Recovery means increasing the status of a fishery from low or very low sustainability and resilience to a moderate or better condition. Recovery actions include restoration measures such as re-stocking and protective fishing restrictions. 

Recovery rest period

A waterbody or a portion of a waterbody that is temporarily not open for fishing.

Recruitment overfished

The rate of harvest above which the recruitment from the exploited stock becomes significantly reduced. It is characterized by a greatly reduced proportion of older fish and very low recruitment year after year. If prolonged, may lead to stock collapse especially if combined with poor environmental conditions.


The capacity of a system (for example a fishery) to absorb disturbance without undergoing a fundamental change.

Restricted Access Fishery

Is a term to describe the management approach when not all anglers are allowed to enter or harvest fish from a fishery. An example is a Special Harvest Licence draw.

Shifting baseline

The incremental lowering of standards, in which each new generation lacks knowledge of how the environment used to be and redefines what is “natural,” according to their experience.

Special Harvest Licences

A Special Harvest Licence (SHL) is obtained via a priority-based draw which WIN card holders can apply for.  If drawn, this currently allows them to purchase tags (2 or 3) for a specified size category of walleye at a lake.  It is currently used as a management tool at a few lakes in the following situations:

    1. To allow some fish to be harvested when angling pressure would otherwise become so high that it would quickly collapse a population.
    2. Where populations of walleye have increased in their numbers, but not fully recovered in other population characteristics yet (e.g. spawning is still irregular, number of supporting ages are low), however a few fish could be harvested.
    3. There are particular sizes of fish that can be harvested to provide more opportunity than would otherwise be available with minimum size limits without jeopardizing recovery or maintenance.

Using Special Harvest regulations for walleye have been very successful over the last 10 years at providing for recovery and some smaller opportunity or harvest.


The concept of sustaining the ecological, economic, and social adaptive capacity of a system.

Sustainable Harvest Fishery

This category of harvest fishery is optimized for stable recruitment and sustainable harvest of young adult fish.  The abundance of large, older fish is relatively low.  This management objective provides anglers with harvest opportunities while maintaining a sustainable and resilient fish population.


A regularly interacting or interdependent group of things forming a unified whole. For example, a management system.

Systems thinking

‘Systems thinking’ utilize habits, tools and concepts to develop an understanding of the interdependent structures of (dynamic) systems. When people are included and have an understanding of a system, they are better able to identify the leverage points that lead to desired outcomes.


Inherent characteristics of a fish and fish population for example behaviour that contributes to its susceptibility to capture by angling.

Updated: Aug 21, 2017