First use of a non-invasive technique for determination of sex hormones in the queen conch Lobatus gigas, Mollusca Gastropoda

Profiles were generated of the sex hormones estrogen, progesterone, and testosterone in the marine snail Lobatus gigas every 2 months for 1 year. A non-invasive technique involving feces collection was used. Hormones were extracted from the feces with 80% methanol. After filtering, hormone concentrations were measured by high-performance liquid chromatography and a UV detector. All three sex hormones were present in L. gigas feces, and their concentrations increased contemporaneously with the conch reproductive period. Males and females showed the highest concentration of testosterone in May (1.8 ± 0.3 and 2.1 ± 0.8 ng/ml, respectively). Both sexes presented a maximum estrogen concentration in May (1.2 ± 0.7 and 1.0 ± 0.3 ng/ml). Progesterone in females remained constant from March to July. Pearson correlation between estrogen and spawning activity were r = 0.66 (p = 0.03) and for testosterone (r = 0.5216) and progesterone (r = 0.437). This study constitutes the first use of this technique in this species. Results show that sex hormones may be controlling this species’ reproductive events, as occurs in other gastropods. The understanding of the L. gigas reproductive process, this is one of several steps that will allow in the future improve aquaculture systems and supporting conservation of wild populations.