Differences in Energy Expenditures and Growth Dilution Explain Higher PCB Concentrations in Male Summer Flounder

Madenjian, Charles P.; Jensen, Olaf P.; Rediske, Richard R.; O’Keefe, James P.; Vastano, Anthony R.; Pothoven, Steven A.

doi:10.1371/journal.pone.0147223

Cited by 8 publications

(19 citation statements)

References 62 publications

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“…Female summer flounder grew sufficiently faster than male summer flounder such that by age 8, females were nearly double the size, by weight, of males [27]. In contrast, the sex differences in growth rates were modest for burbot, sea lamprey, cisco, and lake whitefish [22–26].…”

Section: Sex Difference In Pcb Concentrationsmentioning

confidence: 99%

“…Thus, in all eight species, whole-fish PCB concentration in males was greater than whole-fish PCB concentration in females. After consideration of all four abovementioned hypotheses, the most likely primary driver of the sex difference in PCB concentrations was consistently identified as a higher rate of energy expenditure rate in males compared with females [ 3 , 7 , 8 , 22 – 27 ]. The pattern was persistent, regardless of whether the fish species were freshwater or marine.…”

Section: Sex Difference In Pcb Concentrationsmentioning

confidence: 99%

“…In light of new findings, the conclusion drawn in the first synthesis that the growth dilution effect could substantially contribute to the observed sex difference in some cases, but not serve as the primary driver of the difference, appeared to be sound. Female summer flounder grew sufficiently faster than male summer flounder such that by age 8, females were nearly double the size, by weight, of males [ 27 ]. In contrast, the sex differences in growth rates were modest for burbot, sea lamprey, cisco, and lake whitefish [ 22 – 26 ].…”

Section: Sex Difference In Pcb Concentrationsmentioning

confidence: 99%

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Sex differences in contaminant concentrations of fish: a synthesis

et al. 2016

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A comparison of whole-fish polychlorinated biphenyl (PCB) and total mercury (Hg) concentrations in mature males with those in mature females may provide insights into sex differences in behavior, metabolism, and other physiological processes. In eight species of fish, we observed that males exceeded females in whole-fish PCB concentration by 17 to 43 %. Based on results from hypothesis testing, we concluded that these sex differences were most likely primarily driven by a higher rate of energy expenditure, stemming from higher resting metabolic rate (or standard metabolic rate (SMR)) and higher swimming activity, in males compared with females. A higher rate of energy expenditure led to a higher rate of food consumption, which, in turn, resulted in a higher rate of PCB accumulation. For two fish species, the growth dilution effect also made a substantial contribution to the sex difference in PCB concentrations, although the higher energy expenditure rate for males was still the primary driver. Hg concentration data were available for five of the eight species. For four of these five species, the ratio of PCB concentration in males to PCB concentration in females was substantially greater than the ratio of Hg concentration in males to Hg concentration in females. In sea lamprey (Petromyzon marinus), a very primitive fish, the two ratios were nearly identical. The most plausible explanation for this pattern was that certain androgens, such as testosterone and 11-ketotestosterone, enhanced Hg-elimination rate in males. In contrast, long-term elimination of PCBs is negligible for both sexes. According to this explanation, males not only ingest Hg at a higher rate than females but also eliminate Hg at a higher rate than females, in fish species other than sea lamprey. Male sea lamprey do not possess either of the above-specified androgens. These apparent sex differences in SMRs, activities, and Hg-elimination rates in teleost fishes may also apply, to some degree, to higher vertebrates including humans. Our synthesis findings will be useful in (1) developing sex-specific bioenergetics models for fish, (2) developing sex-specific risk assessment models for exposure of humans and wildlife to contaminants, and (3) refining Hg mass balance models for fish and higher vertebrates.

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Section: Sex Difference In Pcb Concentrationsmentioning

confidence: 99%

Section: Sex Difference In Pcb Concentrationsmentioning

confidence: 99%

Section: Sex Difference In Pcb Concentrationsmentioning

confidence: 99%

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Sex differences in contaminant concentrations of fish: a synthesis

et al. 2016

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“…A difference in carbon and nitrogen stable isotope ratios between the sexes may reflect a difference in habitat utilization and/or a difference in food habits between the sexes [24,46,47]. However, carbon and nitrogen stable isotope ratios did not significantly vary between the sexes of white suckers from the Kewaunee River population based on the results from an earlier study [48], indicating that this explanation was unlikely.…”

Section: Discussionmentioning

confidence: 80%

Ratio of Mercury Concentration to PCB Concentration Varies with Sex of White Sucker (Catostomus commersonii)

et al. 2018

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Abstract:The whole-fish total mercury (Hg) concentrations were determined in 25 mature female and 26 mature male white suckers (Catostomus commersonii) caught during their spawning run in the Kewaunee River, a tributary to Lake Michigan. The age of each fish was estimated using thin-sectioned otoliths, and total length (TL) and weight were determined for each fish. When adjusted for the effect of age, males were found to be 7% higher in Hg concentration than females. Nearly all (about 98%) of the Hg found in the white suckers was determined to be methylmercury. In an earlier study on the same 51 white suckers from the Kewaunee River spawning run, males were found to be 18% higher than females in polychlorinated biphenyl (PCB) concentration. We determined that the ratio of Hg concentration to PCB concentration in females was significantly higher than that in males. Thus, sex significantly interacted with contaminant type (Hg or PCBs) in determining contaminant concentrations. The most plausible explanation for this interaction was that males eliminated Hg at a faster rate than females, most likely due to the boosting of the Hg-elimination rate by certain androgens such as testosterone and 11-ketotestosterone. Hg concentrations in the white suckers were well below federal guidelines for fish consumption.

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“…A difference in carbon and nitrogen stable isotope ratios between the sexes may signal a difference in habitat utilization and/or a difference in food habits between the sexes [1,18,34]. However, in an earlier study, carbon and nitrogen stable isotope ratios were shown not to significantly vary between the sexes of Lake Michigan white suckers that spawn in the Kewaunee River [35], suggesting that this hypothesis was invalid.…”

Section: Discussionmentioning

confidence: 99%