Fish and Aquatic Conservation

Lutenizing Hormone – Releasing Hormone (LHRHa) INAD #8061

photo of a paddlefish swimming in vegetation
Paddlefish can be distinguished from other freshwater fish by the presence of a very large mouth, and a long, paddle-shaped snout (called a rostrum) that is about one third the length of the body. Credit: Ryan Hagerty/USFWS


Luteinizing Hormone - Releasing Hormone analogue (LHRHa) is a solution that is applied as either an intraperitoneal (IP) or intramuscular (IM) injection. LHRHa is only available for purchase through Syndel USA. The use of hormones to induce spawning in fish is critical to the success of many aquatic programs that needs hormone treatment to complete final gamete maturation to ensure spawning. The primary goal of field studies conducted under INAD #8061 is to generate data to help determine appropriate LHRHa treatment regimens for inducing gamete maturation in a variety of cultured and wildstock finfish species. Fish may be treated at a dose range of 5 to 120 microgram (µg) LHRHa per kilogram (kg) body weight with single or multiple IP or IM injections. Multiple injections will generally consist of a single “priming dose,” followed by a single “resolving dose.” Fish may be immediately released for human food use. Note: if MS222 or Aqui-S® 20E is used at time of injection, then the withdrawal time for the anesthetic must be followed. To participate in the INAD Program for LHRHa visit the  data collecting site.

Please read the Study Protocol prior to any treatments. IIt 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 pivotal data needed to establish the effectiveness of LHRHa to induce gamete maturation in a variety of fish species.

Drug Name
Luteinizing-Hormone-Releasing Hormone analogue – LHRHa

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: IM or IP injection only, implants not permitted

Treatment dosage:

  • 5 - 120 microgram (μg) LHRHa per kilogram (kg) body weight

Treatment regimen:

  • Single or multiple treatment. Multiple treatment will generally consist of a single "priming dose," followed by a single "resolving dose." Administered IP or IM.

Investigational Withdrawal period:

  • No investigational withdrawal period is required for treated fish.
  • Note: if MS222 or Aqui-S 20E is used at time of injection, then the withdrawal time for the anesthetic must be followed.

Concomitant treatments:

  • Only MS222 or Aqui-S® 20E can be used during the LHRHa treatments. No other chemicals are allowed to be administered for 2 weeks prior; during; or 2 weeks after the LHRHa treatment. Contact AADAP for additional information regarding concomitant treatments.

Required test parameters:

  • This is not for use for fish to produce caviar.
  • Investigator must collect data reporting percent ovulation and/or percent spermiation in treated fish. Investigator should also report general fish behavior and any adverse effects relating to treatment.

Limitations or restrictions on use of drug:

  • Investigator must follow all instructions in the Study Protocol for INAD 8061 regarding drug acquisition and handling, fish treatment and disposition, and data reporting requirements.
  • Use of LHRHa implants is not authorized
  • Drug discharge must be in compliance with local NPDES permitting requirements.

Required INAD fee: $700/facility/year

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