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f <br />1 <br /> <br />1 <br />1 <br /> <br />t <br />1 <br /> <br />1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />about 10 mm anterior to the pelvic girdle and about 5 mm lateral to the mid-ventral line. <br />For smaller fish (< 165 mm), the insertion location was immediately posterior to the <br />pectoral fin and lateral to the mid-ventral line. The insertion location for fish PIT <br />tagged in the dorsal musculature was about 5-10 mm below and posterior to the origin of <br />the dorsal fin. To eliminate variability between workers, one person was responsible for <br />PIT tagging all fish. Tags and needles were disinfected with 70% isopropyl alcohol. <br />Fish from the control and each test group received a specific 'external mark' in the <br />pelvic fin to distinguish them from the other groups. Also, this would alert us to PIT <br />tags that had been expelled and lost following implantation. <br />After handling and tagging, fish in all groups were weighed to the nearest 1 g and <br />measured to the nearest 3 mm TL. Tag presence and code identity (individual ten-digit, <br />alpha-numeric code) were confirmed for all tagged fish following weighing and <br />measuring. This was performed using a portable, hand-held, battery-powered <br />detector/decoding system (Identification Devices model HS-0033). <br />In the field studies, fish were retained in an enclosed live net for approximately <br />24-48 h before release. In the laboratory studies fish were returned to the circular tank <br />immediately after handling. <br />Fish Monitoring <br />Study sites were periodically monitored following the handling and tagging of fish. <br />The approximate elapsed time (days) from release to subsequent monitorings was, <br />Gardner Pond: 2, 133, 343, 351, and 430; 13th-hole Pond: 2, 114, 296, 360, and 437; West <br />Pond: 2, 212, and 310; Humphrey Pond: 2, 22, and 183. <br />10 <br />