Increasing contamination with persistent bioaccumulating compounds is reported for the aquatic ecosystems of Antarctica. These substances mainly originating from distant sources are transported via the atmosphere at a global scale and are re-distributed in the aquatic environment by condensation and precipitation. These xenobiotics are accumulating in organisms (bioaccumulation), however, the effects on the various members of the food web are rarely investigated.
The Protocol on Environmental Protection to the Antarctic treaty emphasizes that the protection of the Antarctic environment is in the interest of mankind as a whole. Accordingly, the development and implementation of suitable procedures for environmental impact assessment in Antarctic areas affected by human settlement has to become a priority task.
To evaluate the health of the ecosystem it is one approach to study sensitive indicator species (= sentinel species). Sentinel species have been well established for various ecosystems. However, in Southern Ocean fishes, investigations on the suitability as sentinel species are still missing and a clear need for much more information on the response of polar marine species was addressed. Such species should be selected according to criteria of their role in the food web, their physiological capabilities to respond sensitively and to their prior exposure to chemicals. As a consequence, we focus on three ground fish species as they are representing different roles in the food web, e.g. the benthos feeding yellow notothenia (or bumphead notothenia Gobionotothen gibberifrons), the fish feeder Scotia Sea icefish (or blackfin icefish, Chaenocephalus aceratus) and the krill feeding mackerel icefish (Champsocephalus gunnari).
As a consequence, this project aims at assessing the general potential of Antarctic groundfish species to cope with bioaccumulating organic toxicants and elucidate their potential as sentinel species. Therefore, we will study (1) if their physiological capability to accumulate and metabolise persistent organic pollutants is different from well-investigated sentinel species of boreal latitudes. With this, we attempt to raise first evidence whether one or more of the three Antarctic fish species are apt as sentinel species. (2) We will further study whether potential effects of preceding exposure to persistent bioaccumulating compounds affected health and selected biomarkers of these species. To raise these data, persistent organic pollutants will be measured in the fish muscle. Furthermore, endpoints will be studied such as condition factor, hepatosomatic index, spleenosomatic index, histopathology of liver and gill, as well as selected biomarkers.
Work at sea
Fish sampling will profit from the fishing program of the survey on the biology and ecology of Antarctic groundfish. This fishing will be conducted within the remit of CCAMLR and is thus due to specific research exemptions both under the Antarctic Treaty and CCAMLR. Accordingly, no additional fish has to be taken. From the provided three fish species, only male specimen of a specific maximum length (corresponding to age < 3 years) will be investigated to exclude sex differences, which are known to influence the bioaccumulation potency and the responsiveness of the biomarkers. At selected sampling sites, 20 fish fulfilling the mentioned criteria will be 90 - ANT-XXVIII/4 - sampled. Whole fish will be studied for biometric parameters. Muscle tissue will be dissected and preserved for further analysis of persistent organic pollutants (P. Schmid, EMPA). Liver, gill and muscle tissue will be sampled for biomarker analysis and PCR of selected enzymes of the detoxification metabolism.