Effects of age, sex and reproductive status on persistent organic pollutant concentrations in ‘‘Southern Resident” killer whales

Authors

Margaret M. Krahn, NOAA FisheriesFollow
M. Bradley Hanson, NOAA Fisheries
Gregory Schorr, Cascadia Research CollectiveFollow
Candice K. Emmons, NOAA Fisheries
Douglas G. Burrows, NOAA Fisheries
Jennie L. Bolton, NOAA Fisheries
Robin W. Baird, Cascadia Research CollectiveFollow
Gina M. Ylitalo, NOAA FisheriesFollow

Date of this Version

2009

Citation

Marine Pollution Bulletin 58 (2009) 1522–1529; doi:10.1016/j.marpolbul.2009.05.014

Abstract

‘‘Southern Resident” killer whales (Orcinus orca) that comprise three fish-eating ‘‘pods” (J, K and L) were listed as ‘‘endangered” in the US and Canada following a 20% population decline between 1996 and 2001. Blubber biopsy samples from Southern Resident juveniles had statistically higher concentrations of certain persistent organic pollutants than were found for adults. Most Southern Resident killer whales, including the four juveniles, exceeded the health-effects threshold for total PCBs in marine mammal blubber. Maternal transfer of contaminants to the juveniles during rapid development of their biological systems may put these young whales at greater risk than adults for adverse health effects (e.g., immune and endocrine system dysfunction). Pollutant ratios and field observations established that two of the pods (K- and L-pod) travel to California to forage. Nitrogen stable isotope values, supported by field observations, indicated possible changes in the diet of L-pod over the last decade.