Catch per unit effort

In fisheries and conservation biology, the catch per unit effort (CPUE) is an indirect measure of the abundance of a target species. Changes in the catch per unit effort are inferred to signify changes to the target species' true abundance. A decreasing CPUE indicates overexploitation, while an unchanging CPUE indicates sustainable harvesting.[1]

CPUE has a number of advantages over other methods of measuring abundance. It does not interfere with routine harvesting operations, and data are easily collected. The data are also easy to analyse, even for non-specialists, in contrast to methods based on transects. This means that decisions about stock management can also be made by the people doing the harvesting.[1] The best practice is to standardise the effort employed (e.g. number of traps or duration of searching), which controls for the reduction in catch size that often results from subsequent efforts.[2]

Although CPUE is a relative measure of abundance, it can be used to estimate absolute abundances.[3] The main difficulty when using measures of CPUE is to define the unit of effort.[4] CPUE is also often nonlinearly related to abundance, making interpretation more difficult.[5]

  1. ^ a b Pablo E. Puertas & Richard E. Bodmer (2004). "Hunting effort as a tool for community-based wildlife management in Amazonia". In Kirsten M. Silvius, Richard E. Bodmer & José M. V. Fragoso (ed.). People in Nature: Wildlife Conservation in South and Central America. Columbia University Press. pp. 123–136. ISBN 978-0-231-12783-7.
  2. ^ William J. Sutherland (2000). "Monitoring". The Conservation Handbook: Research, Management and Policy. Wiley-Blackwell. pp. 36–64. ISBN 978-0-632-05344-5.
  3. ^ J. R. Skalski, Kristen Elaine Ryding & Joshua J. Millspaugh (2005). "Analysis of population indices". Wildlife Demography: Analysis of Sex, Age, and Count Data. Academic Press. pp. 359–434. ISBN 978-0-12-088773-6.
  4. ^ Working Party on Marine Mammals (1978). "General aspects of population biology". Mammals in the Seas. FAO Fisheries Series, Number 5. Vol. 1. Food and Agriculture Organization. pp. 142–154. ISBN 978-92-5-100511-8.
  5. ^ Harley, Shelton J; Myers, Ransom A; Dunn, Alistair (2001-09-01). "Is catch-per-unit-effort proportional to abundance?". Canadian Journal of Fisheries and Aquatic Sciences. 58 (9): 1760–1772. doi:10.1139/f01-112. ISSN 0706-652X.