2 Evolution of PSP Toxicity in Shellfish from the Beagle Channel. . .
17
of sessile organisms like large sponges (Vinuesa 1993). The data showed that an
A. catenella bloom began during October/November 1991 in southern Chilean
waters and it was detected for the first time in the Strait of Magellan. Then, it spread
south and eastwards affecting Beagle Channel waters (Lembeye 1992).
Since this exceptional outbreak, detectable PSP toxin levels have been recorded
every year in molluscs from Beagle Channel, with levels exceeding the safety limit
being generally recorded in late spring and summer. Some poisoning in humans
has occurred due to consumption of shellfish collected by residents sampling near
the affected areas. In October, 2009, PSP levels increased in some harvesting areas,
and in December shellfish harvesting was banned along the entire Beagle Channel.
Unlike previous years, many areas had to remain closed until winter due to an
unusual persistence of toxicity in shellfish. A similar pattern was recorded during
the following year.
Purpose
The aim of this article is to document the multi-year (1985–2011) trend of PSP
levels in bivalve mollusc samples obtained from the Argentinean coasts at Beagle
Channel, in shellfish harvesting areas where monitoring activities are conducted. By
showing how episodes of PSP toxicity have evolved through time, the reported data
are expected to be a suitable aid to develop predictive models and adjust monitoring
strategies for dealing with PSP toxicity episodes.
Materials and Methods
Samples of Mytilus edulis chilensis and Aulacomya ater were obtained at different
points of the Beagle Channel (Fig. 2.1) between August, 1985, and May, 2011. They
were shipped for analysis to the Mar del Plata Regional Laboratory of SENASA
and/or to the Environmental Laboratory of Ushuaia. The technique used for PSP
detection was the mouse bioassay (AOAC International 2000) using the albino
mouse strain CF1. These animals are regularly supplied to the two laboratories from
the central mouse breeding facilities of SENASA in Buenos Aires. Sample toxicity
was expressed in g of saxitoxin-equivalent per 100 g of meat (g STX eq.100 g
1 ).
Conversion factor (CF) value applied in both laboratories was 0.19. The limit of
detection (LOD) of the bioassay was within the 30–35 g STX eq.100 g
1 range.
The established Federal guideline of 80 g STX eq.100 g
1 was applied to
determine whether harvesting areas were to be open or closed (Reglamento de
Inspecci´ on de Productos).
17
of sessile organisms like large sponges (Vinuesa 1993). The data showed that an
A. catenella bloom began during October/November 1991 in southern Chilean
waters and it was detected for the first time in the Strait of Magellan. Then, it spread
south and eastwards affecting Beagle Channel waters (Lembeye 1992).
Since this exceptional outbreak, detectable PSP toxin levels have been recorded
every year in molluscs from Beagle Channel, with levels exceeding the safety limit
being generally recorded in late spring and summer. Some poisoning in humans
has occurred due to consumption of shellfish collected by residents sampling near
the affected areas. In October, 2009, PSP levels increased in some harvesting areas,
and in December shellfish harvesting was banned along the entire Beagle Channel.
Unlike previous years, many areas had to remain closed until winter due to an
unusual persistence of toxicity in shellfish. A similar pattern was recorded during
the following year.
Purpose
The aim of this article is to document the multi-year (1985–2011) trend of PSP
levels in bivalve mollusc samples obtained from the Argentinean coasts at Beagle
Channel, in shellfish harvesting areas where monitoring activities are conducted. By
showing how episodes of PSP toxicity have evolved through time, the reported data
are expected to be a suitable aid to develop predictive models and adjust monitoring
strategies for dealing with PSP toxicity episodes.
Materials and Methods
Samples of Mytilus edulis chilensis and Aulacomya ater were obtained at different
points of the Beagle Channel (Fig. 2.1) between August, 1985, and May, 2011. They
were shipped for analysis to the Mar del Plata Regional Laboratory of SENASA
and/or to the Environmental Laboratory of Ushuaia. The technique used for PSP
detection was the mouse bioassay (AOAC International 2000) using the albino
mouse strain CF1. These animals are regularly supplied to the two laboratories from
the central mouse breeding facilities of SENASA in Buenos Aires. Sample toxicity
was expressed in g of saxitoxin-equivalent per 100 g of meat (g STX eq.100 g
1 ).
Conversion factor (CF) value applied in both laboratories was 0.19. The limit of
detection (LOD) of the bioassay was within the 30–35 g STX eq.100 g
1 range.
The established Federal guideline of 80 g STX eq.100 g
1 was applied to
determine whether harvesting areas were to be open or closed (Reglamento de
Inspecci´ on de Productos).