PARENT SESSION
Oral Session 13: Rare, Threatened, and Endangered Species I: Management I.
Presiding: H Balbach
Monday, August 2, 8:00 AM to 11:30 AM, Meeting Room D 135.

Population change criteria: An approach to recovery goals for threatened species.

McElhany, Paul^*,1, Payne, John^*,1, ¹ NOAA Fisheries, Seattle, WA

ABSTRACT- Recovery planning for threatened and endangered species benefits from setting clear recovery goals. In the case of Endangered Species Act (ESA) -listed species, "measurable and objective" delisting criteria are required for all recovery plans. We developed an approach to setting recovery goals (Population Change Criteria - PCC) that has broad application to many species. Through the use of modeled "viability curves" we identify combinations of abundance and productivity that would produce an acceptable extinction risk. The observed growth rate is used as a measure of the productivity, and the target is defined as a specific abundance in a given number of years. The approach differs from simple minimum size thresholds by focusing on the change in population abundance over time. Data required for setting and evaluating PCC targets are relatively minimal (i.e. abundance estimates), making the method appropriate in situations where more complex analyses are not possible. The assumption that productivity equals growth rate causes the criteria to be more precautionary than the recruits per spawner methods commonly used in fisheries. The method is currently being used to establish delisting criteria for ESA-listed Pacific salmonids, where we had to include modification of the basic method to account for the presence of hatchery-origin spawners and for decadal-scale patterns of variation in marine survival. A publicly available computer program (SPAZ) allows rapid calculation of the PCC targets from available data.

Key words: recovery goals, salmon, delisting criteria, population change criteria