Behavioural tests were used to determine whether juvenile flatfishes w
ere capable of detecting and avoiding sediment containing various conc
entrations of petroleum hydrocarbons. Three species of juvenile Alaska
n flatfishes: rock sole (Pleuronectes bilineatus), yellowfin sole (P.
asper), and Pacific halibut (Hippoglossus stenolepis) were tested in l
aboratory chambers containing contaminated mud or sand offered in comb
ination with clean mud, sand or granule. The flatfishes were able to d
etect and avoid heavily oiled (2%) sediment, but they did not avoid lo
wer concentrations of oiled sediment (0.05%). Oiled sediment was favou
red over unoiled sediment if the unoiled sediment was of the grain siz
e not preferred by that species. Oiled sand or mud was always preferre
d over unoiled granule. The observed lack of avoidance at concentratio
ns likely to occur in the environment may lead to long-term exposure t
o contaminated sediment following a spill. Recruitment of juveniles ma
y be affected if the exposure to oil is long enough to affect growth a
nd survival.