New publication
Krahn, M.M., M.B. Hanson, G.S. Schorr, C.K. Emmons,
D.G. Burrows, J.L. Bolton, R.W. Baird and G.M. Ylitalo. 2009. Effects of age,
sex and reproductive status on persistent organic pollutant concentrations in
"Southern Resident" killer whales. Marine Pollution Bulletin.
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.
Robin