Table 1.

Sampling dates

Month	Sampling dates
	2004	2005	2006
January	–	17	10, 26
February	–	22	10, 26
March	8	10	14
May	20	11	–
June	–	15	–
July	–	12	–
August	–	30	–
September	30	8, 22	–
October	26	13, 27	–
November	6, 14, 22	15, 30	–
December	19	9, 25	–

–, indicates no sampling.