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Dietary calcein marking of shovelnose sturgeon and the effect of sunlight on mark retention

January 1, 2011

Calcein, a fluorochrome dye, is a potential fish‐marking agent that has not been evaluated in sturgeon. Shovelnose sturgeon Scaphirhynchus platorynchus (average weight, 9.7 g) were fed calcein, immersed in a calcein bath, or left unmarked to determine calcein mark intensity. In the first study, six treatments were evaluated in a two‐by‐three factorial arrangement. Feed was formulated with 2.0 g of SE‐MARK/kg either as powder or in an encapsulated form. Sturgeon were fed the test diets for 5, 10, or 15 d. They readily ate feed containing powdered or encapsulated calcein. Sturgeon fed powdered calcein had more brilliant marks than those fed encapsulated calcein (8.27 versus 4.66 lm; P < 0.03) 6 months postexposure. Fish fed calcein for 15 d (11.26 lm) were more brilliant (P < 0.002) than fish fed for either 5 d (3.02 lm) or 10 d (5.11 lm). Post hoc comparison of the three treatment groups showed that sturgeon fed powdered calcein for 15 d (14.06 lm) were brighter (P < 0.01) than fish fed encapsulated calcein (8.46 lm) or fish immersed in calcein (9.68 lm). In the second study, previously marked sturgeon were exposed to sunlight for 14 months to determine their retention of calcein marks. Dorsal marks were no longer visible on fish exposed to 100% sunlight after 8 weeks. Most but not all fish exposed to 20% sunlight had no discernable dorsal marks after 8 weeks, but ventral marks at the pectoral fin girdle were present on all fish in the 0% and 20% sunlight exposure treatments. Feeding calcein for 15 d appears to have excellent potential for practical application, such as distinguishing hatchery‐reared from wild fish. Ventral calcein marks remained visible after 14 months of exposure to 20% sunlight when sturgeon were reared in clear water.

Citation Information

Publication Year 2011
Title Dietary calcein marking of shovelnose sturgeon and the effect of sunlight on mark retention
DOI 10.1080/15222055.2011.559869
Authors D. C. Honeyfield, G.A. Kindschi, T.A. Bell, J.W. Mohler
Publication Type Article
Publication Subtype Journal Article
Series Title North American Journal of Aquaculture
Index ID 70035052
Record Source USGS Publications Warehouse
USGS Organization Leetown Science Center

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