Types of GEM
Category 1b GeM Project Example: Trade in Fish and Wildlife
Two distinct applications of genetic sampling exist with regard
to monitoring markets in fish and wildlife products. The first
uses genetic information obtained directly from markets to explore
patterns in natural populations. The second uses genetic information
to determine the species or source population of animals found
in markets. We provide recent examples of each below.
Commercial and traditional markets for wildlife and fisheries
present important opportunities for genetic monitoring of biodiversity.
Whereas the primary objective of past market surveys has been
to document illegal trade in species, it is less well appreciated
that market surveys, over time, can also provide information on
changes in species composition (diversity) and even for inferring
population dynamics (abundance and effective population size)
of species subject to direct or indirect exploitation (Baker
2008). With the appropriate sampling design for collection
of samples from market products and application of standard or
modified statistical analyses (e.g., assignment tests, mixed-stock
of capture-recapture), market surveys can fulfill many of the
primary objectives of genetic monitoring for many natural populations
that would otherwise fall outside of conventional monitoring programs.
efforts gather tusks from across Africa in single, large shipments.
Therefore, even when officials are fortunate enough to intercept
a shipment and confiscate their contents, they may not be able
to reliably determine the origin. This limits the opportunities
to focus enforcement, education, and conservation efforts in affected
Wasser et al. (2004) developed a method to identify the geographic
origin of confiscated ivory across the entire range of African
elephants, including areas where no samples had been genotyped.
Their method uses similarities in allele frequencies across multiple
samples (tusks) simulataneously. They found this method to be
more accurate than pairwise sample analyses.
Another advantage of their method is that is can estimate how
much confidence to place in assigned sample origins by comparing
relative support across mutiple putatitve locations. Accuracy
of assignment is a function of both sample size and genetic characteristics
of the source population (i.e., diversity and degree of separation
from other populations). Therefore, as the size of the reference
dataset grows, the ability to identify the origin of confiscated
Contrary to initial expectations, Wasser et al. (2007) found
that the ivory was entirely from savanna elephants, likely originating
from a narrow east-to-west strip centering on Zambia. Wildlife
authorities initially suspected that this ivory came from multiple
locations across forest and savanna Africa. However, we show that
These findings enabled law enforcement to focus their investigation
to a smaller area and fewer trade routes and led to changes within
the Zambian government to improve antipoaching efforts. Such outcomes
demonstrate the potential of genetic analyses to help combat the
expanding wildlife trade by identifying origin(s) of large seizures
of contraband ivory.