We analyzed the total mercury (T-Hg) and stable isotopes of (13)C and (15)N in the muscle of spiny dogfish (Squalus acanthias) caught off the coast of Japan. The average body length of the female spiny dogfish sampled (94.9 +/- 20.2 cm, 50.5-131.0 cm, n = 40) was significantly larger than that of the males sampled (77.8 +/- 10.8 cm, 55.5-94.0 cm, n = 35), although the ages of the samples were unknown. The T-Hg concentration in the muscle samples rapidly increased after maturity in the females (larger than about 120 cm) and males (larger than about 90 cm), followed by a continued gradual increase. Contamination level of T-Hg in female muscle samples (0.387 +/- 0.378 mu g (wet g)(-1), n = 40) was slightly higher than that in male muscle samples (0.316 +/- 0.202 mu g (wet g)(-1), n = 35), probably due to the greater longevity of females. In contrast, the contamination level of T-Hg in females smaller than 94.0 cm in length (0.204 +/- 0.098 mu g (wet g)(-1), n = 20) was slightly lower than that in the males, probably due to the faster growth rate of females. Although the partial derivative(13)C and partial derivative(15)N values in the muscle samples increased with an increase in body length, there were no significant differences between the females (-17.2 +/- 0.4 parts per thousand and 12.4 +/- 0.9 parts per thousand, respectively) and males (-17.3 +/- 0.4 parts per thousand and 12.4 +/- 0.8 parts per thousand, respectively). A positive correlation was found between partial derivative(13)C and partial derivative(15)N values, suggesting trophic enrichment due to the growth. (C) 2009 Elsevier Ltd. All rights reserved.
