Non-invasive genetic analysis reveals high levels of mtDNA variability in the endangered South-American marine otter (Lontra felina)

Abstract

Scats from marine otters were collected from the entire Peruvian distribution range along the Pacific coast. Partial mtDNA control region sequences (265 bp) were successfully amplified and analysed in 37 out of 87 samples. Based on spatial distribution and home range information of marine otters we assumed our final data set to represent at least 24 different individuals, yielding surprisingly high genetic variability (11 haplotypes, h = 0.86, p = 0.0117). No unequivocal evidence of genetic substructuring, a bottleneck or isolation by distance could be detected. This study presents the first genetic data in this endangered species and highlights the significance of the Peruvian gene pool for the establishment of reserves, potential future expansion, recolonisation or translocations.

The marine otter Lontra felina ( ): A review of its present status and implications for future conservation

“…Considering the most frequently reported densities of 1.0-2.7 ind/km the population is estimated to range from 789 to 2131 individuals at the Peruvian coast. Molecular analysis revealing high levels of mitochondrial DNA (mtDNA) variability (Valqui et al 2010;Vianna et al 2010) and further data on occurrence might support this data, indicating that the population numbers reported in the last years were underestimated. Medina-Vogel et al (2006) discuss the uncertainty of the methodology in most surveys done in the last decades, while they propose minimum abundance indices rather than total survey numbers.…”

“…In 1959, the German naturalist Ernst Schweigger travelled along the Peruvian coast and documented marine otters up to Isla Lobos de Tierra (6 • 26 S), representing the northernmost record of L. felina (Schweigger 1964). Later studies registered the species only up to Chimbote (9 • 00 S), Peru (Brack 1978;Brownell 1978;Larivière 1998;Apaza et al 2004;Sánchez and Ayala 2006;Valqui et al 2010). Recent records of the marine otter in Salaverry (8 • 13 S) (Santillán and Caro 2007) and Huanchaco (8 • 04 S) (Alfaro-Shigueto et al in press), Peru, suggest that occasional events of colonization may occur north of 9 • 00 S, but several factors may hinder the establishment of populations in those areas: (1) rocky shore patches have been occupied by dogs, cats and rats; (2) lack of food availability exists due to a higher competition of the species with a more intensive fishery (Apaza et al 2004); (3) the distances between suitable habitat patches may impede gene flow.…”

“…Interruptions average 9.1 km in length and are maximal 98.4 km long (calculation by the author). Some conspicuous groups of marine otters are present in Pucusana (12 • 28 S), Punta Corrientes (12 • 57 S), San Gayán Island (13 • 50 S), Morro Sama (17 • 59 S) and Vila Vila (18 • 07 S) (Sánchez 1992;Apaza et al 2004;Valqui 2004;Ruiz 2009;Mangel et al 2010;Valqui et al 2010). See Table 1 (online appendix) for a complete list of locations with marine otter presence and abundance numbers.…”

“…Studies on behavior, diet, reproduction and/or ecology were made in the second part of the 20th century. The first genetic studies were published in 2010 (Valqui et al 2010;Vianna et al 2010). However, further information on population numbers, migration and genetics are still needed to achieve a better understanding and to provide arguments for conservation measures of this top predator.…”

Un libro sobre observaciones de la nutria marina en Tacna, Perú

“…Así por ejemplo, la distribución geográfica de la nutria y sus variaciones en densidad son un problema donde no se precisan las causas, y en el libro se recurren a teorías generales para explicarlas, mientras que pudieran discutirse aspectos más actuales que sin duda se enlazan al problema de la conservación y evaluación poblacional; este último aspecto denota la carencia de datos precisos que pudieran ingresar a modelos poblacionales y la ausencia de discusión de trabajos muy importantes sobre la nutria marina en el Perú como los de Juan Valqui (Valqui et al 2010, Valqui 2012). …”