bottom-up management:

A process of management in which information and decisions are decentralized and in which resource users actively participate in the decision-making process.


The portion of a fishing catch that is discarded as unwanted or commercially unusable.

cascading effect (or trophic cascade):

A food web phenomenon in which changes in abundance at a higher trophic level lead to changes in abundance at lower trophic levels.


The total number (or weight) of organisms caught by fishing operations. Catch should include all organisms killed by the act of fishing, not just those landed.

catch control rule:

A formula used to determine the catch quota as a function of some specific indicators of stock status and any other variable condition used to adjust annual harvest targets. The control rule provides numeric guidance for adjusting catch rates to track forecasts of fluctuations in stock abundance and to achieve management goals. In many fisheries, it is the primary mechanism for regulating harvest rates.

catch quota:

A limit placed on the total catch allowed within a particular period of time.

commercial fisheries:

Harvesting fish for profit. This includes those caught for sale, barter, and trade.

decadal oscillation:

Cyclical changes where shifts occur on scales of roughly 10 years.


To reduce in value or level. In this context, degraded is used to describe ecosystems that have been exploited to a point where there is a loss of desired uses, including a reduction in overall productivity or the loss of species.


A situation in which mortality rate increases and/or reproduction decreases as the size of the population decreases.

Ecopath model:

An ecological/ecosystem modeling software used to develop a static, mass-balanced representation of the feeding interactions and nutrient flows in an aquatic ecosystem.


The amount of fishing gear of a specific type used on the fishing grounds over a given unit of time; e.g., hours trawled per day, number of hooks set per day or number of hauls of a beach seine per day. When two or more kinds of gear are used, the respective efforts must be adjusted to some standard type before being added.

El Niño:

Abnormally warm ocean climate conditions which, in some years, affect the Eastern coast of Latin America (centered on Peru) often around Christmas time and which occasionally can be transmitted northward to Alaskan waters. The anomaly is accompanied by dramatic changes in species

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