TY - JOUR T1 - Sampling design optimization for EROD measurements in fish A1 - Beliaeff,Benoit A1 - Burgeot,Thierry AD - IFREMER, F-44311 NANTES 3, FRANCE. UR - https://archimer.ifremer.fr/doc/00337/44787/ DO - 10.3354/meps153239 KW - biomonitoring KW - estimation KW - EROD activity KW - statistical power KW - sample size KW - sampling design N2 - Activity of 7-ethoxyresorufin-O-deethylase (EROD) in fish is certainly the best-studied biomarker of exposure applied in the field to evaluate biological effects of contamination in the marine environment. Since 1991, a feasibility study for a monitoring network using this biomarker of exposure has been conducted along French coasts. Using data obtained during several cruises, this study aims to determine the number of fish required to detect a given difference between 2 mean EROD activities, i.e. to achieve an a priori fixed statistical power (l-beta) given significance level (alpha), variance estimations and projected ratio of unequal sample sizes (k). Mean EROD activity and standard error were estimated at each of 82 sampling stations. The inter-individual variance component was dominant in estimating the variance of mean EROD activity. Influences of alpha, beta, k and variability on sample sizes are illustrated and discussed in terms of costs. In particular, sample sizes do not have to be equal, especially if such a requirement would lead to a significant cost in sampling extra material. Finally, the feasibility of longterm monitoring is discussed. Y1 - 1997 PB - Inter-research JF - Marine Ecology Progress Series SN - 0171-8630 VL - 153 SP - 239 EP - 246 ID - 44787 ER -