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Summary: Peru has the second-highest diversity of birds in the world, but little is known about the interactions between birds and plastic waste. To fill this knowledge gap, we searched the scientific literature, collected information from social networks such as Facebook and databases such as Macaulay Library and iNaturalist and solicited records through messaging with researchers and bird enthusiasts. We found 119 bird interactions with plastic debris involving 39 species from 20 families, with the red-legged cormorant Phalacrocorax gaimardi and the neotropical cormorant Phalacrocorax brasilianus being the most affected species. By type of interaction category, plastic waste in nests was the most abundant, followed by entanglement, capture and handling and ingestion. Ropes, nets and soft plastics such as bags were the most frequently reported types of waste. As our methodology has limitations, it is probable that other species that also interact with plastic waste have not been reported, so we recommend further study. [ABSTRACT FROM AUTHOR]

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Arias-Schreiber (2003) found that 20% of SAFS and 32% of SASL samples contained cephalopod beaks, whereas in our study cephalopod consumption was significantly different between otariids, with 32% in SAFS in comparison with 1.6% in SASL. Trophic overlap was detected in the austral summer and fall of 2015 during an extraordinary El Niño event, in which both otariids consumed similar proportions of Peruvian anchovy (55% SAFS, 48.6% SASL), cephalopods (21.7% SAFS, 13.6% SASL) and red squat lobsters (9% SAFS, 2% SASL). Keywords: diet; foraging ecology; fur seal; Peru; sea lion EN diet foraging ecology fur seal Peru sea lion 775 790 16 05/13/22 20220601 NES 220601 Abstract Resource partitioning can contribute to species coexistence by reducing interspecific competition. In regard to crustaceans, Arias-Schreiber (2003) found 8% of SAFS and 60% of SASL samples contained red squat lobster, similar to the 5% and 70% for SAFS and SASL, respectively, found in our study. [Extracted from the article]

Adenoviruses are medium size nonenveloped viruses with a trend of coevolution with their hosts. We surveyed South American fur seals (Arctocephalus australis) and Humboldt penguins (Spheniscus humboldti) for adenoviruses at two sites from 2009 to 2012. Despite the common pattern of host specificity, some of the adenoviruses in our study were present in samples from unexpected host species. We identified mastadenoviruses, aviadenoviruses, and siadenoviruses in A. australis from Peru and Chile and in S. humboldti from Peru. The El Niño Southern Oscillation (ENSO) significantly reduces the productivity of the Humboldt upwelling system, which can change trophic and other ecological interactions, facilitating exposure to new pathogens. One aviadenovirus was detected in both the penguins and the fur seals, an interclass distance. This finding occurred only during the 2009 ENSO and not in 2010 or 2012. Further studies of viral diversity in sites with high-density mixed species populations are necessary to better understand viral evolution and the effect of environmental change on viral evolution and host specificity. [ABSTRACT FROM AUTHOR]

The South American sea lion (Otaria flavescens) is widely distributed along the southern Atlantic and Pacific coasts of South America with a history of significant commercial exploitation. We aimed to evaluate the population genetic structure and the evolutionary history of South American sea lion along its distribution by analyses of mitochondrial DNA (mtDNA) and 10 nuclear microsatellites loci. We analyzed 147 sequences of mtDNA control region and genotyped 111 individuals of South American sea lion for 10 microsatellite loci, representing six populations (Peru, Northern Chile, Southern Chile, Uruguay (Brazil), Argentina and Falkland (Malvinas) Islands) and covering the entire distribution of the species. The mtDNA phylogeny shows that haplotypes from the two oceans comprise two very divergent clades as observed in previous studies, suggesting a long period (>1 million years) of low inter-oceanic female gene flow. Bayesian analysis of bi-parental genetic diversity supports significant (but less pronounced than mitochondrial) genetic structure between Pacific and Atlantic populations, although also suggested some inter-oceanic gene flow mediated by males. Higher male migration rates were found in the intra-oceanic population comparisons, supporting very high female philopatry in the species. Demographic analyses showed that populations from both oceans went through a large population expansion ~10,000 years ago, suggesting a very similar influence of historical environmental factors, such as the last glacial cycle, on both regions. Our results support the proposition that the Pacific and Atlantic populations of the South American sea lion should be considered distinct evolutionarily significant units, with at least two managements units in each ocean. [ABSTRACT FROM AUTHOR]

Sympatric species evolve mechanisms to avoid competition and coexist. In the Humboldt Current System (HCS), populations of South American sea lions (SASL, Otaria byronia) and South American fur seals (SAFS, Arctocephalus australis) fluctuate mostly due to ENSO events and prey availability. We evaluate population trajectories of Peruvian sympatric otariids and discuss mechanisms for competition and/or resource limitation. For this purpose, we analyzed population trajectories of SASL and SAFS in a sympatric breeding site in Punta San Juan, Peru between 2001 and 2019. Wavelet analysis was used to extract trends and derivatives to estimate rates and turning points. Age-class proportions and biomass times series were constructed from weekly counts and evaluated. Both populations show a growth phase and subsequent decline. SAFS started to decline ~2.25 years before and at a rate 1.5 times faster than SASL. Decrease in juvenile age-class suggests that resource limitation is the main contributing factor for current population decline. [Display omitted] • Limitations in population growth of Peruvian sympatric otariid populations. • Sea lions are the current 'dominating' otariid species in Peru. • Decrease in juveniles contributes towards population decline. • Resource partitioning between otariids needs to be further explored in Humboldt Current System. [ABSTRACT FROM AUTHOR]

The Humboldt Current System presents high interannual variability, influenced by the El Niño Southern Oscillation (ENSO), whose implications in wildlife are not fully understood. We studied the isotopic niche of wild Humboldt penguins at Punta San Juan (Peru) during the pre-moult foraging trip in 4 consecutive years (2008–2011) under known oceanographic (ENSO) conditions. Our results show that there is a clear isotopic niche segregation (on both δ13C and δ15N values) of wild Humboldt penguins among all years. Besides isotopic niche segregation, niche width also varied significantly among years. The larger isotopic niche displayed in 2008 reflected the opportunistic feeding behaviour of Humboldt penguins when oceanographic conditions were unfavourable (i.e. El Niño of strong intensity). In contrast, and despite strong segregation, penguins displayed a more specialist behaviour in years of mild environmental conditions (i.e. 2009 "warm-weak", 2010 "neutral" and 2011 "warm-moderate"). No evidence of sexual segregation in wild Humboldt penguins during the pre-moulting foraging trip was found. This study highlights the coping mechanisms of an endangered species to changes in environmental conditions (i.e. overall, from strong to neutral El Niño events), which should have important ramifications in the management of the marine ecosystem in Peru, particularly the one related to the anchovy industry. • Strong inter-annual isotopic niche segregation in pre-moulting wild Humboldt Penguins. • Significant variation in the isotopic niche width among years. • No sexual segregation during the pre-moult foraging trip. [ABSTRACT FROM AUTHOR]