Use of a GnRH agonist to suppress testosterone in wild male Hawaiian monk seals (Monachus schauinslandi).

A gonadotropin-releasing hormone (GnRH) agonist, d-Trp6-LHRH, was evaluated for its effectiveness in reducing circulating testosterone concentrations in wild Hawaiian monk seals (Monachus schauinslandi). Twenty-eight adult male seals were randomly divided into three groups: 10 were captured and treated with 7.5 mg of the GnRH agonist, 9 were captured but did not receive the agonist, and 9 were captured near the end of the study to serve as handling controls.

Detection of a non-cultivatable calicivirus from the white tern (Gygis alba rothschildi).

In April 1992, on Tern Island, French Frigate Shoals, Hawaii (USA), researchers observed a hand-reared white tern hatchling (Gygis alba rothschildi) develop vesicular lesions on the webbing between its toes, 6 days after falling out of its nest. Vesicular fluid collected from the foot lesions contained virus-like particles having typical calicivirus morphology. Calicivirus RNA was detected in the vesicular fluid by dot hybridization with a group-specific calicivirus copy DNA probe.

Testosterone response to a gonadotrophin-releasing hormone agonist in Hawaiian monk seals (Monachus schauinslandi).

Adult male Hawaiian monk seals were administered a gonadotrophin-releasing hormone (GnRH) agonist to determine its effectiveness in reducing the testicular production of testosterone. Blood samples were collected from four treated seals and two control seals at weekly intervals for 10 weeks and again at the beginning of the following breeding season. The GnRH-agonist had an initial, brief, stimulating effect on circulating testosterone, but this was followed by an inhibitory effect that lasted for 7 to 8 weeks.

Seasonal testosterone pattern in Hawaiian monk seals (Monachus schauinslandi).

Blood samples from four captive male Hawaiian monk seals were collected at intervals of one month for one year for testosterone assay. Plasma testosterone concentrations, measured by radioimmunoassay, revealed a clear seasonal pattern. The lowest mean testosterone concentration (0.

Pathological findings in the Hawaiian monk seal.

Postmortem examinations were performed on 45 Hawaiian monk seals (Monachus schauinslandi) collected during field research on the beaches of the Northwestern Hawaiian Islands (USA) from 1981 to 1985. Both males and females of all age groups, perinatal through adult, were examined. Frequent findings included parasites, trauma, cardiovascular disease (congenital and acquired), and respiratory infections.