What are management objectives?
Management objectives are formally adopted goals for a stock and fishery. Within a harvest strategy, operational objectives must be specific and measurable, with associated timelines and minimum required likelihoods that they can be achieved. Setting management objectives is the critical first step in developing a harvest strategy. They set the vision for the fishery and provide mechanisms for measuring the strategy’s long-term success. Management objectives can be modified, but if the harvest strategy is going to be effective, it’s critical that modifications occur only if the vision for the fishery truly changes, rather than as a means to justify a desired short-term outcome.
Typical Categories of Management Objectives:
- Status: To maximize the probability of maintaining the stock in the green zone of a fishery’s Kobe plot (i.e., not overfished, no overfishing).
- Safety: To minimize the probability that the stock will fall below the biomass limit reference point or BLIM (i.e., the danger zone, the point beyond which fishing is no longer considered sustainable).
- Yield: To maximize catch (or effort) across regions and/or fishing gears.
- Abundance: To maximize catch rates to enhance fishery profitability.
- Stability: To maximize stability in catches to reduce commercial uncertainty by minimizing variability in catch from year to year.
A Guide to Setting Objectives:
- Set specific and measurable objectives, with associated timelines and acceptable levels of risk. Examples: 5% risk of breaching the limit reference point; 75% chance of rebuilding a stock to the target reference point within 10 years
- Avoid terms that are undefined, such as “high probability” or “in as short a time as possible,” as they can be subject to interpretation and lead to a lack of clarity that complicates management negotiations.
- Set multiple objectives. A stock could be managed to simultaneously maximize a) catch, b) stability in year-to-year catches, c) profit, d) the speed of rebuilding the stock, and e) the likelihood that the population is around a target abundance level and well above any limit.
- Balance tradeoffs when selecting objectives, weighing conflicting objectives like maximizing catch and minimizing the chance of breaching the biomass limit.
- Prioritize objectives geared towards achieving the status and safety objectives for a fishery with a very high probability.
Acceptable Levels of Risk
One of the most critical steps in the harvest strategy development process is choosing the levels of risk that will guide future fishery decisions. Often, these levels are codified in the fishery’s management objectives. Risk is defined in terms of the likelihood of a negative outcome, such as stock collapse or breaching the limit reference point. Conversely, it can establish the probability of success, such as the chance of achieving a target reference point or not breaching the limit reference point. Consistent with the precautionary approach, managers should set low levels of risk tolerance in cases of greater uncertainty. Risk-averse management is preferable because it helps ensure a high probability of achieving the status and safety objectives for a fishery. Alternatively, establishing over-conservative risk levels can result in forgone yield, and so a balance must be struck to ensure suitably precautionary risk tolerances without unnecessary sacrifices in catch.
Guidelines for Risk
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