Cp. Madenjian et al., SEXUAL DIFFERENCE IN POLYCHLORINATED BIPHENYL ACCUMULATION RATES OF WALLEYE (STIZOSTEDION-VITREUM), Canadian journal of fisheries and aquatic sciences, 55(5), 1998, pp. 1085-1092
Adult male walleye (Stizostedion vitreum) exhibited significantly high
er polychlorinated biphenyl (PCB) concentrations than similarly aged f
emale walleye from Saginaw Bay (Lake Huron). To explain this differenc
e, we tested the following three hypotheses: (i) females showed a cons
iderably greater reduction in PCB concentration immediately following
spawning than males, (ii) females grew at a faster rate and therefore
exhibited lower PCB concentrations than males, and (iii) males spent m
ore time in the Saginaw River system than females, and therefore recei
ved a greater exposure to PCBs. The first hypothesis was tested by com
paring PCB concentration in gonadal tissue with whole-body concentrati
on, the second hypothesis was tested via bioenergetics modeling, and w
e used mark-recapture data from the Saginaw Bay walleye fishery to add
ress the third hypothesis. The only plausible explanation for the obse
rved difference in PCB accumulation rate was that males spent substant
ially more time in the highly contaminated Saginaw River system than f
emales, and therefore were exposed to greater environmental concentrat
ions of PCBs. Based on the results of our study, we strongly recommend
a stratified random sampling design for monitoring PCB concentration
in Saginaw Bay walleye,with fixed numbers of females and males sampled
each year.