Fish and Aquatic Conservation

Lutenizing Hormone – Releasing Hormone (LHRHa) INAD #8061

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: Doug Canfield/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 100 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.” Adherence to a 14-d Investigational withdrawal period is required before treated fish can be released or slaughtered as food fish. Use of LHRHa analog pellet implants is not authorized. To participate in the INAD Program for LHRHa 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 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

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 - 100 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:

  • 14 days for all fish

Required test parameters:

  • 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