EVALUATION OF TRACE ELEMENT CONCENTRATIONS IN THE SERUM AND VIBRISSAE OF PERUVIAN PINNIPEDS (ARCTOCEPHALUS AUSTRALIS AND OTARIA BYRONIA)

Concentrations of 15 trace elements (aluminum, arsenic, cadmium, chromium, cobalt, copper, iron, lead, manganese, mercury, nickel, selenium, tin, vanadium, and zinc) were determined in vibrissae (whiskers) and serum of two sympatric pinniped species, the Peruvian fur seal population (PFS; Arctocephalus australis Peruvian subpopulation) and South American sea lion (SASL; Otaria byronia) at Punta San Juan, Peru during 2011–19 sampling events. Element concentrations were 2–20 times higher in vibrissae than in serum. Vibrissae and serum concentrations of several elements, including aluminum, arsenic, and lead, suggest that environmental contaminants may affect the health of pinnipeds at Punta San Juan. Although toxicity thresholds are unknown in pinnipeds, high concentrations of some elements (especially aluminum, arsenic, and lead) may have adverse impacts on their health such as immunosuppression and impaired reproduction. Arsenic was the only element that increased in mean vibrissae concentration throughout the study period. Female SASL vibrissae contained a mean arsenic concentration three times higher than the male SASL vibrissae mean arsenic concentration, and twice as high as the arsenic mean for all PFS vibrissae. The mean male SASL vibrissae cadmium concentration was five times higher than the vibrissae cadmium mean for both PFS males and females and nearly three times higher than the vibrissae cadmium mean for SASL females. Serum concentrations of aluminum, arsenic, copper, and manganese were significantly higher during moderate to extreme El Niño years compared to La Niña years. With stronger and more frequent El Niño-Southern Oscillation events predicted in the future, it is vital to understand how these trace elements may affect pinniped population health

Sympatric otariids increase trophic segregation in response to warming ocean conditions in Peruvian Humboldt Current System

Determining trophic habits of predator communities is essential to measure interspecific interactions and response to environmental fluctuations. South American fur seals, Arctocephalus australis (SAFS) and sea lions Otaria byronia (SASL), coexist along the coasts of Peru. Recently, ocean warming events (2014–2017) that can decrease and impoverish prey biomass have occurred in the Peruvian Humboldt Current System. In this context, our aim was to assess the effect of warming events on long-term inter- and intra-specific niche segregation. We collected whisker from SAFS (55 females and 21 males) and SASL (14 females and 22 males) in Punta San Juan, Peru. We used δ13C and δ15N values serially archived in otariid whiskers to construct a monthly time series for 2005–2019. From the same period we used sea level anomaly records to determine shifts in the predominant oceanographic conditions using a change point analysis. Ellipse areas (SIBER) estimated niche width of species-sex groups and their overlap. We detected a shift in the environmental conditions marking two distinct periods (P1: January 2005—October 2013; P2: November 2013—December 2019). Reduction in δ15N in all groups during P2 suggests impoverished baseline values with bottom-up effects, a shift towards consuming lower trophic level prey, or both. Reduced overlap between all groups in P2 lends support of a more redundant assemblage during the colder P1 to a more trophically segregated assemblage during warmer P2. SASL females show the largest variation in response to the warming scenario (P2), reducing both ellipse area and δ15N mean values. Plasticity to adapt to changing environments and feeding on a more available food source without fishing pressure can be more advantageous for female SASL, albeit temporary trophic bottom-up effects. This helps explain larger population size of SASL in Peru, in contrast to the smaller and declining SAFS population

Maternal offloading of arsenic and other trace elements in Peruvian fur seals

The maternal transfer of 15 elements was examined in Peruvian fur seal (Arctocephalus australis) dam and pup paired vibrissae (whiskers), serum, and milk samples collected from 2009 to 2019. Pup vibrissae, grown in utero, represented gestational transfer, while milk represented lactational transfer. Element concentrations, except arsenic, were highest in vibrissae compared to serum and milk for both dams and pups. Mean arsenic concentrations in pup vibrissae (0.44 μg/g) and milk (0.41 μg/g) were twice as high as dam vibrissae concentrations (0.19 μg/g) and nearly ten times higher than dam (0.06 μg/g) and pup serum (0.04 μg/g) concentrations. Mean arsenic concentrations from 2011 to 2019 increased in dam vibrissae (0.026 μg/g to 0.262 μg/g) and milk (0.361 μg/g to 0.484 μg/g). Pup vibrissae had significantly higher concentrations for 11 of the 15 elements analyzed compared to dam vibrissae, suggesting that element transfer is occurring through recent exposure and remobilization of elements from dam body stores. Potentially high concentrations of aluminum, arsenic, copper, and lead in pup tissues may impact their survival and population health. The impact of regional mining activities can contribute to elevated trace elements through runoff and pose a possible threat to local marine environments

Effects of nest type and sex on blood saccharide profiles in Humboldt penguins (Spheniscus humboldti): Implications for habitat conservation.

Reproductive success of endangered Humboldt penguin (Spheniscus humboldti) colonies in Peru has been associated with nesting habitat type, presumably due to differences in environmental exposure and activity patterns that may affect energy demands and metabolism. Gas chromatography and mass spectrometry were used to determine serum concentrations of 19 saccharides from 30 Humboldt penguins nesting at Punta San Juan, Peru in order to evaluate differences in metabolic state between penguins nesting in a sheltered burrow or crevice (n = 17) and those in exposed surface nests (n = 13). Univariate and multivariate statistical analyses identified serum saccharides (arabinose, maltose, glucose-6-phosphate, and levoglucosenone in particular) that were nest-dimorphic with substantial differences between surface- and sheltered-nesting penguins. Four sugars (arabinose, xylose, fructose-6-phosphate, and sucrose) had ≥ 2-fold difference in concentration between nest types. Seven saccharides were in the top five subsets generated by discriminant analysis; four of these are simple sugars (D-glucopyranose, α ⇄ β; D-glucose; D-maltose; and D-mannose) and three are derivatives (glucose 6-phosphate, levoglucosenone, and N-acetylglucosamine). D-ribose had the highest information values (generated from weight-of-evidence values) followed by glucose 6-phosphate, levoglucosenone, and D-galactose. Sex was not a significant predictor of saccharide concentration. Levoglucosenone, which is a metabolite of the environmental contaminant levoglucosan, was significantly higher in surface-nesting penguins, reflecting a higher rate of exposure in non-sheltered penguins. Differences in the saccharide profiles of surface- and sheltered-nesting Humboldt penguins likely reflect increased metabolic requirements of surface-nesters at Punta San Juan. Conservation of appropriate sheltered-nesting habitat for penguins is essential for sustained reproductive success and colony health

Peruvian pinnipeds as archivist of ENSO effects off the coast of Peru

Environmental fluctuations in the eastern Pacific Ocean are reflected in the tissues of one of its most vulnerable apex predators, the Peruvian fur seal Arctocephalus australis. The coastal waters off Peru are a region of great environmental fluctuations due to periodic (every 2-7 years) El Niño-Southern Oscillation (ENSO) events, which result in ecosystem-wide food web changes. Pinniped body tissues reflect the incorporation of prey from the region, which can be evaluated using stable carbon and nitrogen isotope ratios (δ13C and δ15N). Continuously growing tissues, like vibrissae (whiskers), can potentially provide a large scale timeline of environmental data in an ecosystem where changes regularly occur and human instrumentation to measure such changes is sparse. Sea surface temperature (SST) anomalies along the Peruvian coastline are encompassed in the body of water known as Niño 1+2; a SST anomaly index used to categorize ENSO events. This region distinguishes itself from the more widely studied water bodies Niño 3, 3.4, and 4 by exhibiting more frequent and shorter-lived heating and cooling oscillations in SST. These oscillations appear to coincide with the δ13C and δ15N signatures recorded in the Peruvian fur seal vibrissae collected from 2010 (n=29), 2011 (n=12), 2012 (n=11) and 2015 (n=12). The δ13C and δ15N covary along the vibrissal length except for distinct points where their patterns are inversely related. These points are identified as transition periods between the region’s rapidly changing El Niño/La Niña phases. Adult female δ13C values throughout all sampled years (n=49), ranged from -18.13 to -13.19 ‰ ± 0.33 ‰. This reflects wide fluctuations in ocean production over time, which is our proxy to ENSO effects. Preliminary δ15N values range from 15.83 to 21.55 ‰ ± 0.85 ‰. These data suggest that these fur seals might be using alternative foraging survival strategies during these ENSO periods by foraging at two or more trophic levels. These may be the first biologic data of their kind to reveal how abiotic, ecosystem-wide changes influence the trophic dynamics and resultant survivability of the Peruvian fur seal

Abiotic Stressors Expose Peruvian Fur Seal Parental Care

Vulnerable Peruvian fur seals (PFS) Arctocephalus australis are genetically isolated subspecies of South American fur seals and have a major breeding colony in Punta San Juan, Peru. PFS display strong site fidelity on densely populated rookeries, likely due to their highly productive foraging environment associated with upwelling. PFS are susceptible to strong environmental fluctuations known as El Niño-Southern Oscillation (ENSO) events, evidenced by sea surface temperature anomaly (SSTA) fluctuations in the Niño 1+2 index. Fur from 2009 (15 adults, 28 pups), 2010 (28 adults, 27 pups) and whiskers from 2015 (6 dam-pup pairs) are comprised of keratin and are isotopically comparable. Stable carbon and nitrogen isotope ratios (δ13C and δ15N) were employed to detect patterns in foraging habits and how they are reflected in pup tissues. The difference in δ15N between adult females and pups was no more than 0.8‰ in all three years, and both age classes had an average overall decline of 1.6‰ from 2009 to 2015. This is in contrast with δ13C; females in 2009 and 2015, as well as pups, had nearly identical values. The 2010 adult δ13C were significantly more enriched by 0.8‰ compared to the other two years, likely indicative of a more productive food web. The adult fur represents growth during the peak of the 2010 moderate La Niña phase (a cooler, productive period), while the pup lanugo, depleted by ~0.5‰ compared to the two other years, was grown during both the ENSO normal and moderate La Niña phase. The lipid-rich diets consumed by the dams of these pups may have provided additional lipid during critical fetal growth that would be represented in depleted δ13C exhibited in the pup fur. The combined isotopic data from foraging adults and their developing fetuses provide finer-scale resolution of the effects of ecosystem change than population estimates

Strategies for segregation during foraging in sympatric otariids of the Peruvian upwelling Humboldt Current System

The competitive exclusion principle predicts that species exhibit segregation mechanisms to coexist. In the Humboldt Current System, South American sea lions Otaria byronia (SASL) coexist with South American fur seals Arctocephalus australis (SAFS); however, the existence of temporal and spatial partitioning in foraging strategies remains unknown. To compare foraging strategies, we analyzed locations of 35 adults (18 SASL, 17 SAFS; 4 and 8 females, 14 and 9 males, respectively) equipped with satellite tags in Punta San Juan, Peru (2013-2017). We evaluated (1) distance and duration of foraging trips, (2) utilization distributions (UDs), (3) foraging by hour and (4) association of foraging with environmental variables. Regular interval tracks (every 30 min) were modeled, and residence time was estimated to determine foraging events. Proportion overlap and analysis of similarity compared groups in core areas (50% UD) and home ranges (95% UD). Generalized additive mixed models were built to determine if hour of day and environmental conditions had an effect on foraging. Multiple mechanisms for foraging segregation that explain coexistence were found. Duration and distance between species-sex groups were significantly different, except for trip duration between SASL sexes. SAFS traveled longer distances and duration than SASL, and males traveled longer distances and duration than conspecific females. Female UDs overlapped, while male UDs did not. Core areas between sexes overlapped in SAFS and SASL, but home ranges were significantly different. Hour of day had a significant effect on foraging events in SAFS females and SASL males. Environmental conditions during foraging by SASL and SAFS females reflected coastal and offshore habitats, respectively. However, interspecific segregation was not evident between males