Drug Summary & History
Calcein INAD 10-987

Fisheries professionals have long been interested in fluorescent chemicals that can be used to safely, effectively, and quickly mark (by immersion) large numbers of larval and juvenile fishes. Calcein is a fluorochrome compound that chemically binds with alkaline earth metals such as calcium and, upon binding, shows a marked increase in fluorescence when excited with blue light of about 500 nm wavelength. A number of laboratory-scale studies have shown that static-bath immersion marking with calcein can be an effective way to mark otoliths, vertebrae, fin rays, scales, and other calcified structures of fishes and other aquatic animals. A number of these marks can easily be detected in the field on live fish. Although calcein-marking appears to have tremendous utility as a fisheries management tool, to date, production-scale use of calcein has been limited.

The primary goal of INAD #10-987 is to generate data to help determine appropriate calcein treatment regimens for mass-marking a variety of fishes under a variety of environmental conditions. Under this INAD, SE-MARK® (Western Chemical, Inc.,Ferndale, WA) is the only form of calcein (1% active, pH 7.0 balanced solution) authorized for use by all Investigators. Two treatment options (see A and B below) are allowed. Treatment is restricted to fish that are 2 grams or less in weight. No withdrawal time is required for fish weighing 2 grams or less. No slaughter authorization is provided for fish weighing more than 2 g.

Treatment Option A (marking): Administer calcein in a static bath at 125 - 250 mg/L active drug for 1 - 6 h followed by transfer to fresh water. Administer as a single- or multiple-treatment. If multiple treatments are administered to induce multiple marks, allow at least 2 d between treatments.

Treatment Option B (marking): Immerse fish in a static-bath containing a 1 - 5% salt solution (use noniodized salt) for about 3.5 min followed by immersion in a static-bath containing 2.5 - 5.0 g/L active drug for 1 - 7 min followed by transfer to fresh water. Administer as a single- or multiple-treatment. If multiple treatments are administered to induce multiple marks, allow at least 2 d between treatments.