A comparison of methods for tagging juvenile lobsters (Homarus gammarus L.) reared for stock enhancement

Comparing two types of internal tags in juvenile blue crabs

“…(3) Microwire was more detectable in the field as crabs grew to >65 mm CW, leading to more accurate population estimates. These results differ from those of the few other studies comparing elastomer and microwire, in which differences between the tag types were not observed in brown and rainbow trout (Hale and Gray, 1998) or juvenile lobsters (Linnane and Mercer, 1998). The disparity between these and our study may be attributed to differences in characteristics of our study species.…”

“…Reports of mortality rates are equally wide-ranging, but can also depend on animal size for both elastomer and microwire (Frederick, 1997;Linnane and Mercer, 1998). Although tagging can have an immediate mortality effect (Uglem and Grimsen, 1995, this study), most studies, like ours, do not report a tag effect on long-term mortality for either microwire (e.g., van Montfrans et al, 1986;Fitz and Wiegert, 1991;Uglem and Grimsen, 1995) or elastomer (Bailey et al, 1998;Malone et al, 1999;Davis and Ovaska, 2001).…”

“…First, autotomy of the tagged swimming leg was common. Second, elastomer often migrated over time up into the more calcified body, making detection difficult (also noted in lobster, Linnane and Mercer, 1998). Third, the proximal segment of the swimming leg calcifies and becomes less transparent as the crab grows, making elastomer difficult to detect.…”

“…Estimates of long-term (one to several months) elastomer retention rates include 60% in squawfish (Haines et al, 1998), 92-100% in lobster (Uglem et al, 1996;Linnane and Mercer, 1998), and 100% in shrimp (Godin et al, 1996). Factors contributing to variability include site of tag insertion (Kneib and Huggler, 2001), experience of people operating the tagging equipment (Bailey et al, 1998;Close, 2000), and conditions in which animals are kept (Guy et al, 1996).…”

“…However, this tag had not, until now, been compared with other options such as the elastomer tag in any crab species. Elastomer, a colored polymer developed by NMT (also known as visual implant flourescent elastomer (VIE or VIFE)) is often used to tag fishes (e.g., Frederick, 1997;Bailey et al, 1998) but has been assessed in only a few crustaceans (crayfish and lobsters: Uglem et al, 1996;Linnane and Mercer, 1998;Willis and Babcock, 1998;Jerry et al, 2001). Elastomer is less invasive and more affordable than microwire and is detectable without expensive equipment.…”