Persistent organic pollutants in living southern right whale (Eubalaena australis) mothers and calves at Península Valdés, Argentina.

MARON CARINA; HUED A; CECCHETTO FRANCO; VAZQUEZ NICOLAS; UHART MARCELA; SSIRONI M; BERTRAND L; AME, M.V; MIGLIORANZA KARINA SILVIA BEATRIZ

Simposio; Scientific Committee of the International Whaling Commission?s Document SC/69A/E02. Presented at the Sub-Committee on Environmental Concerns,; 2023

Persistent organic pollutants (POPs) comprise contaminants used for agricultural orindustrial purposes. POPs are globally distributed via the atmosphere and transferred tohigher latitudes that act as sinks for these contaminants [1], [2]. Bioaccumulation andbiomagnification of POPs have been detected in Antarctic fauna reflecting not only globalpollution but also the use of these contaminants in the Southern Hemisphere. The effects ofPOPs on the health of individuals have been associated with failures in reproduction, changesin the normal functioning of the endocrine system, increased risk of infection and immunesuppression [3]-[5]. In marine mammals, there is increasing evidence of these contaminantscontributing to high mortality events in several species, because of the strong effects of POPson nutritional condition and health [5]-[7].The southern right whale (SRW, Eubalaena australis) population that calves offPenínsula Valdés (PV), Argentina, has been studied continuously since 1971. Annual deathsappeared to mirror the population’s growth until the 2000s. However, mortality has spiked inthe past years. Over 2003-2013, calf mortality has averaged 55 deaths per breeding season,greatly surpassing previous decade’s (1993-2002) average of 8.2 yearly. Furthermore, in2012, 113 first-season calves died (33% of calves born). This represents the highest numberof natural mortalities both for the population and for calves ever to be recorded for thespecies in a single year [8]–[10].Such high numbers of calf deaths are unheard of in baleen whales, and severalhypotheses have been proposed to explain this high mortality [11]–[13]. Assessment of POPspresence and concentration in mother-calf pairs at PV has been proposed as one of thepriorities for research [12], since in cetaceans, reproductive females accumulate POPs in theirtissues (especially blubber) and transfer them to their calves through lactation [14]-[16],potentially compromising the offspring´s health. The presence of chemical pollutants(organochlorine pesticides and polychlorinated biphenyls) has been previously recorded inthe blubber of 35 SRW dead calves [17]. This finding indicates that SRW calves likelyacquire toxic chemicals during gestation (through the placenta) and lactation (through milk).However, no study has yet analyzed the presence and concentration of these pollutants inliving SRW, especially in reproductive females and their newborn calves. Furthermore, thisstudy proposes to characterize POPs concentrations in other groups of the SRW population atPV (male adults and juveniles) and compare them to reproductive females who may havelower concentrations since they eliminate some of these chemicals through lactation.