Fish and Aquatic Conservation

Calcein (Se-Mark®) INAD #10-987

photo of Early juvenile longfin smelt
Early juvenile longfin smelt. Credit: Bureau of Reclamation


Calcein (Se-Mark®) is a liquid that contains 1% calcein for bath marking treatments on finfish and select freshwater mussels. Calcein is only available for purchase through Syndel USA. 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. The primary goal of field studies conducted under INAD #10-987 is to establish the effectiveness of calcein to mark fin rays, scales, otoliths, and other calcified fish, oysters, or selected mussel tissues via immersion baths. This is a non-lethal marking evaluation method. The treatment options available for treating fish are 1) 125 - 250 milligram (mg) calcein per liter for 1 – 6 hours; or 2) 2.5 - 5.0 gram (g) calcein per liter (finfish only) for 1 - 7 minutes. Note: Treatment 2 may include a pre-treatment with a 1 - 5% salt solution for ~3.5 minutes. The treatment regimen for oyster spat is 250 mg/L for 24 hrs. Due to the treated fish and oyster size restrictions (fish <2 g and oyster spat <25mm) and limited mussel species authorized for treatment, there is no Investigational withdrawal period associated with use of calcein under this INAD. To participate in the INAD Program for calcein visit the data collecting site.

Please read the Study Protocol prior to any treatments. It contains the protocol, MSDS, and a copy of the forms to be used as a guide for collecting data that will be entered into the online INAD database. The FDA authorization letter(s) for this INAD is currently only available by emailing Bonnie Johnson .

INAD objective/purpose: Collect supportive and/or pivotal data needed to establish the effectiveness of calcein to mark fin rays, scales, otoliths, and other calcified structures in fish, oysters, or selected mussel tissues via immersion bath.

Drug Name
Calcein (SE-MARK®)

Drug Source
Syndel USA
1441 W Smith Rd,
Ferndale, WA 98248 USA

Jason Montgomery
Phone: 800-283-5292
Fax: 360-384-0270

Target pathogen(s): Not Applicable

Method of administration: Immersion: standing-bath treatment only

Treatment dosage:

  • Option A: 125 – 250 milligram (mg) calcein per liter
  • Option B: 2.5 - 5.0 gram (g) calcein per liter (finfish only)

Treatment regimen:

  • Option A: Treatment duration is 1 - 6 hr
  • Option B: Treatment duration is 1 - 7 min (Note: Treatment may include a pretreatment with a 1 -5% salt solution for ~3.5 min.)
  • Option C: Treament duration is 24 hr for oyster spat only
  • Calcein may be applied as a single treatment, or repeated treatments.

Investigational Withdrawal period:

  • None for fish; they may be released immediately following treatment for those treated at less than 2 grams (fish) or less than 25 mm (oyster spat) and for Federally Threatened and Endangered species.
  • None for mussels; due to their treatment at an early life stage and the limited human consumption

Required test parameters:

  • Investigator must collect mark retention and mortality data. Investigator should also report general fish behavior and any adverse effects relating to treatment.

Limitations or restrictions on use of drug:

  • Treatment is restricted to finfish having a body weight of 2 grams or less.
  • Treatment is restricted to oyster spat less than 25 mm.
  • Treatment of mussels is restricted to the following species: Higgins eye, hickory nut, black sandshell, pocketbook, fat mucket, sheepnose and maple leaf.
  • Repeated treatments may be conducted to establish mutltiple marks. However, an interval of at least 2 days should be observed between treatment events.
  • No discharge of calcein marking solution is allowed. Although used calcein marking solution may be stored on station in a secure, leak-proof container, it must ultimately be disposed of according to procedures detailed in a general Waste-stream profile (see INAD Study Protocol for specific instructions).
  • Investigator must follow all instructions in the Study Protocol for INAD 10-987 regarding drug acquisition and handling, fish treatment and disposition, and data reporting requirements.

Required INAD fee: $700/facility/year

AADAP Contact Information:
Ms. Bonnie Johnson, FWS-AADAP
Phone: 406-994-9905
Fax: 406-582-0242