Page 55 - World Aquaculture Magazine - March 2011

World Aquaculture 53
farm practices, production and awareness of the cadmium
issue. Additional information was compiled from Washing-
ton Department of Health (number, type and location of
HC growers), Washington Department of Fish and Wild-
life (price, production), National Oceanic and Atmospheric
Administration (export destination, price, production) and
United States Department of Agriculture-National Agri-
cultural Statistics Service Census of Aquaculture. The com-
bined data were used to estimate one-time revenue losses as-
sociated with rejected product and future losses associated
with the redirection of HC oysters to the domestic market.
Results and Discussion
Geographic and seasonal distribution of cadmium in Pacific
oysters
Several regions of similar tissue cadmium concentration
were observed during the initial sampling event in Septem-
ber 2004. Most notable were lower concentrations found in
SPS, WA and at the mouth of HC, WA; and consistently
elevated concentrations along the length of HC, WA and
Alaska. Seasonal cadmium concentrations (2004-2006) and
their relationship to Hong Kong’s 2 µg/g import limit are
displayed in Figure 8.
Economic assessment of Hood Canal, Washington
In October 2005, the HKFEHD rejected 910 dozen X-
small oysters from southern HC for measuring 3.9 µg/g
cadmium. As a result, a temporary suspension on the im-
portation of all oysters from that particular growing area
was instated. To better understand the financial implica-
tions of import restrictions, such as those imposed by the
HKFEHD, an economic assessment was conducted for the
HC region.
According to the economic report (NEI 2008), the im-
pact of Hong Kong’s 2 µg/g limit on HC shellfish growers
is minimal at this time. Sixty-three licensed shellfish com-
panies are located in HC, which represent 19 percent of
Washington shellfish growers and five percent of the state’s
annual oyster production. Of the 10 growers interviewed,
only two sold product internationally and of those, in-
ternational sales comprised twp percent of total revenue.
Those interviewed indicated that limited international sales
were due in part to an inability to support Asia’s preference
for jumbo sized oysters and difficulties in securing reliable
buyers.
The decision to export product often depends on the size
of the shellfish operation. Our survey determined that small
companies typically rely on the domestic market, while mid-
sized companies minimize risk by selling directly to whole-
salers. Since the 2005 rejection, wholesalers that sell to the
international market are increasingly aware of the cadmium
issue. Several refuse to purchase oysters originating from
one HC shellfish growing area altogether. Large companies
tend to grow various types of shellfish at multiple locations.
This diversification allows larger companies to direct HC
oysters to the domestic market and Puget Sound oysters to
the international market.
Despite the small percentage of international sales from
Fig. 7. Placing oyster seed in off-bottom aquapurses at a farm
in Samish Bay, Washington (Photo by Daniel P. Cheney).
Fig. 8. Seasonal cadmium concentrations (µg/g wet weight)
in C. gigas tissue. The red line indicates Hong Kong’s 2 µg/g
import restriction.
Fig. 9. Exports of oysters to Asia from Seattle. Source: NOAA
Fisheries, Office of Science and Technology.