Latitudinal variation in local productivity influences body condition of South American sea lion pups

Abstract

Local productivity is essentially important for colonial species, such as seabirds and otariids (fur seals and sea lions). These species are central place foragers and income breeders that combine foraging ABSTRACT: In otariids, the condition and growth of offspring are linked to prey availability be cause females show a strong dependence on local food availability. Thus, it is expected that body condition of sea lion pups will vary spatially and/or temporally as a response to variations in the abundance of prey species on which females feed. The objective of this study was to analyze the geographic and temporal variation in the body condition of South American sea lion Otaria flavescens pups in Chile, and to relate it to spatio-temporal variations in prey availability. We captured 340 live pups in 2 distant colonies, Punta Patache/Punta Negra and Cobquecura, along the Chilean coast during consecutive breeding seasons. A morphometric index of pup body condition was estimated by comparing pups in all years using least-squares linear regression of the log 10 -transformed measurements of standard length vs. body mass. We analyzed the relationship between this index and estimates of fish biomass (as a proxy of prey availability) at each locality. We found that body condition was significantly different between years and between colonies, suggesting that animals of the central-south area were in better condition than those in the north. A positive relationship between body condition and fish biomass was found, suggesting that differences in body condition may be explained by spatial and temporal differences in prey availability.

Is regional variability in environmental conditions driving differences in the early body condition of endemic Australian fur seal pups?

“…Low productivity in Bass Strait may be leading to a lower carrying capacity, as Sepúlveda et al . (2014) suggested is occurring for two colonies of South American sea lions ( Otaria flavescens ) in Chile.…”

Long‐term abundance dynamics of the South American sea lion (Otaria flavescens) in the most important breeding colony in central Chile

“…Given that females depend on food resources near the colony during the breeding season (Costa 1993), this sex/age-class is expected to select sites for breed where resources are concentrated and predictable (Pitcher et al 1998), which would explain the high abundance of SASLs in this colony. Sep ulveda et al (2014) showed that the pups of Cobquecura sea lions are in favourable body conditions, which indicates adequate food availability. Additionally, it has been described different seal and sea lion species respond negatively to human presence (e.g.…”

Peruvian Fur Seals as Archivists of El Niño Southern Oscillation Effects

“…These marine mammals serve as sentinel species, indicative of ecosystem health in an environment at the center of fluctuating ENSO conditions (Fossi and Panti, 2017). The feeding ecology and movements of these pinnipeds are of substantial interest as ENSO events continue to intensify in both frequency and magnitude (Sepúlveda et al, 2014). Through a combined analysis of stable isotope profiles and abiotic recordings from El Niño indices, the feeding ecology of the Peruvian fur seal was investigated in Punta San Juan, Peru (Figure 1) over a time series of various ENSO conditions.…”