The CITES criteria for amending Appendices I and II are intended to be applicable for all species, but include specific guidelines for commercially exploited aquatic species in the footnote of Annex 5 of CITES Res. Conf. 9.24 (Rev. CoP14).
Three criteria are provided for determining whether species should be listed in CITES Appendix I (Annex 1 of Res. Conf. 9.24 (Rev. CoP14):
- The wild population is small, and is characterized by at least one of five subcriteria: decline in numbers or habitat; each subpopulation being very small; majority of individuals being concentrated geographically; large short-term fluctuations in abundance; high vulnerability to intrinsic or extrinsic factors.
- The wild population has a restricted area of distribution and is characterized by at least one of four subcriteria: fragmentation or occurrence at few locations; large fluctuations in area of distribution or number of subpopulations; high vulnerability to intrinsic or extrinsic factors; decline in distribution, habitat, number of subpopulations, number of individuals, quality of habitat or recruitment.
- Marked decline in population size in the wild, either ongoing or past, or inferred or projected.
For listing on Appendix II, the criteria indicate that at least one of two criteria must be met (Annex 2a of Res. Conf. 9.24 (Rev. CoP14)):
- Regulation of trade in the species is necessary to avoid it becoming eligible for Appendix I in the near future, or
- Regulation of trade in the species is required to ensure that harvest of wild specimens is not reducing the wild population to a level at which its survival might be threatened by continued harvesting or other influences.
In addition, Annex 2b of Res. Conf. 9.24 (Rev. CoP14) includes the criteria to be met when listing species based on their resemblance to species already listed in Appendix II ("look-alike" species). Definitions and interpretation guidelines are also provided by CITES (Resolution Conf. 9.24 (Rev. CoP14)) to assist in applying the criteria.
As part of its contribution to the review of the CITES criteria, FAO provided a number of observations and recommendations (Report of the second Technical Consultation on the Suitability of the CITES Criteria for Listing Commercially-exploited Aquatic Species) and at the 14th meeting of the Conference of the Parties (CoP14, the Hague, 3-15 June 2007), FAO submitted an information document summarizing the interpretation and application of CITES criteria to commercially exploited aquatic species (CITES COP14, Inf. 64).
With respect to small population size, FAO recommended that the current CITES guidelines for small absolute population size (5 000 individuals) are appropriate for only a few exploited marine species, such as some sessile or semi-sessile species, some species with extremely low productivity, and some small endemics. It was further noted that historical extent of decline
was a more appropriate criterion for exploited marine species.
With respect to restricted area of distribution, FAO stated that the guideline then being discussed of 10 000 km2
was inappropriate for most exploited fish species. Again, historical extent of decline
should be used in preference to this criterion.
With respect to decline
, FAO noted that decline could be expressed either as overall long-term extent of decline or recent rate of decline, and advised that these should be considered together. The time horizon for extent of decline should be as long as possible, while for recent rate of decline the time frame should generally be shorter than 2-3 generations.
Historical extent of decline guidelines for consideration for Appendix I should depend on species productivity (to 5-10% of historical for high productivity species, 10-15% for medium productivity, and 15-20% for low productivity species).
Suggestions for determining productivity based on life history characteristics were provided by FAO (2001):
||0.2 - 0.5
|0.14 - 0.35
(0.16 - 0.5)
|0.15 - 0.33
(0.16 - 0.3)
|t mat (years)
|3.3 - 8
(2 - 4)
|14 - 25
(4 - 10)
(1 - 3)
||5 - 10
||orange roughy, many sharks
Proposed guideline indices of productivity for exploited fish species (numbers in brackets are from Musick 1999), where:
- M natural mortality rate
- r intrinsic rate of increase of a species
- K von Bertalanffy growth rate
- tmat age at maturity
- tmax maximum age
- G mean generation time
Source: A background analysis and framework for evaluating the status of commercially-exploited aquatic species in a CITES context. FAO, 2001.
For listing in Appendix II, the historical extent of decline and the recent rate of decline should be considered in conjunction with one another. The higher the historical extent of decline, and the lower the productivity of the species, the more important a given recent rate of decline is.
A general guideline for a marked recent rate of decline is the rate of decline that would drive a population down within approximately a 10-year period from the current population level to the historical extent of decline guideline (i.e. to 5-20% of the baseline, depending on the species productivity).
It is also implicitly recognized in the CITES criteria that there may be a need to regulate international trade in a species which, although not currently declining, is at a level close to that at which it would become eligible for inclusion in Appendix I (Annex 2a Paragraph A above) or at which its "survival might be threatened by continued harvesting or other influences" (Annex 2a Paragraph B above). These two concerns are well addressed by the Resolution Conf. 9.24 (Rev CoP14), in Annex 5 footnote for commercially-exploited aquatic species in the following paragraph:
"Even if a population is not declining appreciably, it could be considered for listing in Appendix II if it is near the extent-of-decline guidelines recommended above for consideration for Appendix-I-listing. A range of between 5% and 10% above the relevant extent-of-decline might be considered as a definition of ‘near’, taking due account of the productivity of the species."
This creates a buffer zone above the Appendix I thresholds for population status. A species may therefore be considered for listing on Appendix II if the status of the species, as measured by historical extent-of-decline, falls within this buffer zone.
For commercially-exploited aquatic species, the guidelines for the Appendix I extent-of-decline percentages have been set at a population level above the upper bound at which "survival might be threatened by continued harvesting or other influences". The level where those effects become of concern is where depensatory effects, commonly called Allee effects, may negatively influence population dynamics. Since this population level is below the Appendix I thresholds, the same Annex 5 decline guidelines apply to both Paragraphs A and B of Annex 2a.
 Depensation is defined as a negative effect on population growth that becomes proportionately greater as population size declines. Populations experiencing depensation are prone to further reductions in size, even in the absence of exploitation, and therefore have a greater risk of extinction.