In this study, total mercury (THg) variations of Black-tailed Gull (Larus crassirostris) eggs laid on Baengnyeongdo, West Sea of Korea were compared between within- and among clutch in order to ensure statistical representativeness of an egg sampling method. In the ANOVA analysis, the THg variation (59%) among clutches was much higher than within-clutch (27%). This means that the mercury variation of sampled eggs was significantly influenced by the mercury variation among female individuals occupying different nests. In spite of relatively smaller variation of THg in the within-clutch, the THg concentration depending on an egg-laying sequence within a clutch significantly appeared higher in the first-laid eggs rather than the second-laid eggs. Therefore, it is necessary to take one egg from one nest in order to sample more nests in terms of better sampling representativeness. Also, one egg selection from one nest should be consistently applied in order to ensure comparability of mercury concentrations among monitoring sites and monitoring years.

Abstract
 1. 서 론
 2. 연구방법
 3. 결과 및 고찰
  3.1. 한배 산란 둥지 내와 둥지 간 알 크기 변동분석
  3.2. 한배 산란 둥지 내와 둥지 간 알의 수은농도 변동분석
 4. 결 론
 References

• 이장호(국립환경과학원 자연환경연구과) | Jangho Lee Corresponding Author
• 이종천(국립환경과학원 자연환경연구과) | Jongchun Lee
• 장희연(국립환경과학원 자연환경연구과) | Heeyeon Jang
• 박종혁(새만금유역환경청) | Jong-Hyouk Park
• 심규영(국립환경과학원 자연환경연구과) | Kyuyoung Shim