[Show abstract][Hide abstract] ABSTRACT: The island fox (Urocyon littoralis catalinae) population on Santa Catalina Island, California, USA declined precipitously in 1999 with an approximate 95% reduction on their eastern range, an area representing 87% of the island. During this investigation, between October 1999 and April 2000, evidence of live foxes dramatically decreased. The only carcass recovered during the decline succumbed to a co-infection of canine distemper virus (CDV) and toxoplasmosis. Sequence analysis of the viral P gene, derived by polymerase chain reaction, indicated that the virus was closely related to CDV from a mainland USA raccoon (Procyon lotor). Nine of 10 foxes trapped in 1999-2000, on the eastern portion of the island after the decline, had serologic evidence of exposure to CDV, whereas only four of 19 foxes trapped in this region in 1998 had antibodies reactive against CDV. The confirmation of CDV in one deceased fox, evidence of exposure to CDV in east-end foxes in 1999-2000 compared to 1998, and documentation of raccoon introductions to the island, implicates canine distemper as the cause of the population decline.
[Show abstract][Hide abstract] ABSTRACT: Following a dramatic population decline in 1999, captive-breeding and translocation programs were initiated to recover the Santa Catalina Island fox Urocyon littoralis. Neonatal losses during the first year of captive breeding raised concerns, but little information was available on which to base reproductive expectations in captivity, and pregnancy rates and pup mortality had not been assessed in free-ranging foxes. In 2002 and 2003 we evaluated the relative contributions of captive breeding and translocation to population recovery by comparing pregnancy rates and perinatal mortality in free-ranging and captive Santa Catalina Island foxes, and by comparing pregnancy rates and perinatal mortality were also compared between resident free-ranging foxes and foxes that had been captive bred and released, or translocated as juveniles. Pregnancy rates and fetal number were determined using ultrasound. Free-ranging pregnant foxes were followed via radiotelemetry, and a combination of camera-traps, observation and targeted trapping was used to determine how many pups survived to weaning. Video cameras and observations were used to determine the weaning success for captive foxes. The adult pregnancy rate for free-ranging foxes (95.0%) was higher than for adult captive foxes (47.6%; P=0.003). Perinatal mortality for pups born to free-ranging mothers (43.2%) was higher than for pups born to captive mothers (15.0%, P=0.055). Adult pregnancy rates and perinatal mortality were 100 and 25.0% for translocated and captive-bred foxes combined, and 92.3 and 53.6% for resident wild foxes. The average weaned litter size (±standard deviation) for free-ranging foxes (1.8±0.6) was similar to that for captive foxes (2.1±0.4). Successful pup production by translocated and captive-bred foxes supports the utility of these strategies to recover island foxes. Our approach, integrating veterinary and field biology techniques to assess the contributions of different management strategies to population recovery, can be utilized for other endangered species.
[Show abstract][Hide abstract] ABSTRACT: We determined serum biochemistry and hematologic values for island spotted skunks (Spilogale gracilis amphiala) on Santa Cruz Island (California, USA). Samples were collected from island spotted skunks chemically restrained with ketamine hydrochloride and acepromazine in August 1999 (dry season) and from skunks manually restrained in August 2000 (dry season) and January 2001 (wet season). One parameter, glucose, significantly differed with season, with higher levels during the wet season. Serum chemistry and hematologic profiles suggest that method of restraint (manual or chemical), as well as other methodologic details, may influence blood characteristics in the island spotted skunk.