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The article presents the discussion on South American fur seal (Arctocephalus australis; SAFS) is one of the two resident species of pinnipeds inhabiting the Peruvian coast. Topics include SAFS historically suffered catastrophic declines in population size due to El Niño Southern Oscillation (ENSO); and decrease in population numbers left breeding colonies abandoned and caused a reduction in the number of utilized haulouts.

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. [ABSTRACT FROM AUTHOR]

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]

Otariid gammaherpesvirus 1 (OtGHV1) is associated with high rates of urogenital carcinoma in free-ranging California sea lions (Zalophus californianus; CSL), and until recently was reported only in the Northern Hemisphere. The objective of this study was to survey free-ranging South American sea lions (Otaria byronia; SASL) and South American fur seals (Arctocephalus australis: SAFS) in Punta San Juan, Peru for OtGHV1 and to determine prevalence characteristics. Twenty-one percent (14/67) of urogenital swabs collected over three years (2011, 2014, 2015) from live pinnipeds of both species tested positive with a pan-herpesvirus conventional PCR. Sequencing of SAFS amplicons revealed 100% homology to OtGHV1 at the DNA polymerase, glycoprotein B, and viral bcl2-like genes. Sequencing of SASL amplicons revealed a novel related virus, herein called Otariid gammaherpesvirus 8 (OtGHV8). For comparison of sample sites, urogenital, conjunctival, and oropharyngeal swabs collected from 136 live pinnipeds of both species at Punta San Juan between 2011–2018 were then assayed using quantitative PCR for a segment of the OtGHV1/8 DNA polymerase gene using a qPCR assay now determined to cross-react between the two viruses. In total, across both species, 38.6% (51/132) of urogenital swabs, 5.6% (4/71) of conjunctival swabs, and 1.1% (1/90) of oropharyngeal swabs were positive for OtGHV1/8, with SASL only positive on urogenital swabs. Results from SASL were complicated by the finding of OtGHV8, necessitating further study to determine prevalence of OtGHV1 versus OtGHV8 using an alternate assay. Results from SAFS suggest a potential relationship between OtGHV1 in SAFS and CSL. Though necropsy surveillance in SAFS is very limited, geographic patterns of OtGHV1-associated urogenital carcinoma in CSL and the tendency of herpesviruses to cause more detrimental disease in aberrant hosts suggests that it is possible that SAFS may be the definitive host of OtGHV1, which gives further insight into the diversity and phyogeography of this clade of related gammaherpesviruses. [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 undesirable presence of plastic wastes in the marine environment is well known. Reports of effects of plastic wastes on inland continental species are very rare. This report concerns the use of plastic waste by the white-naped squirrel (Simosciurus nebouxii) in agricultural areas of northern Peru. Among the residues observed, single-use plastic bags were prominent. The proximity of solid waste accumulations to all the nests probably may explain why such debris was chosen, except that other nests nearby did not contain plastics. Future studies are recommended to understand the consequences for terrestrial continental fauna of using such materials. [ABSTRACT FROM AUTHOR]

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]

The article focuses on genomic evidence of homoploid hybrid speciation in a marine mammal apex predator, the South American fur seal. It mentions the study provides strong support for the origin of a genetically distinct species, the Peruvian fur seal, through hybridization between the South American fur seal and the Galapagos fur seal approximately 400,000 years ago. It research highlights the role of hybridization in promoting species-level biodiversity in large vertebrates.

The distribution of the long-beaked and short-beaked common dolphin morphs in the eastern South Pacific is not well defined. The objective of this study was to propose a potential distribution of the two forms along the coast of Peru and part of Chile based on the rostral index obtained from the ratio of rostral length and zygomatic width. This phenotypic criterion was implemented in skulls deposited in museum collections in Peru and Chile. Based on classification, we were able to determine the distribution of each morphotype considering the collection location. A total of 44 skulls were analyzed, three of which did not have collection location. The results show that both forms of the common dolphins were distributed along the coast of Peru, but only the short-beaked common dolphin occurred in Chile. A larger number of short-beaked specimens were detected, especially in northern Peru. It was remarkable that the long-beaked was less common than expected since it is usually sighted in neritic waters. Around the 13° S latitude degrees seems to be an overlapping area with specimens of the two forms. Our study provides an analysis of the distribution of the two forms of common dolphins by implementing a discrimination index developed for North Pacific populations. Some patterns of segregation were observed, but this should be contrasted with a larger number of skulls and the application of other phenotypic criteria specific to the South Pacific. [ABSTRACT FROM AUTHOR]

The canid genus Lycalopex comprises six recently diversified South American species whose evolutionary relationships have been remarkably challenging to resolve. We analyzed 6000 bp of mitochondrial DNA (mtDNA) from 55 Lycalopex individuals (L. sechurae = 4, L. culpaeus = 7, L.griseus = 8, L.gymnocercus = 17, L.vetulus = 13 and L. fulvipes = 6), and nine specimens from the closely related species Cerdocyon thous, Chrysocyon brachyurus and Speothos venaticus, to reconstruct their phylogenetic relationships, estimate the support for species-level monophyly, and date their divergences. In addition, we also sequenced seven nuclear segments from the same taxa. Three different phylogenetic approaches converged on the same mitochondrial topology with strong support for most nodes. All species were confirmed to be monophyletic for mtDNA, except for one intriguing case in which two L. vetulus individuals carried L. gymnocercus haplotypes, potentially implying a case of interspecies admixture. L. vetulus was the first species to diverge (ca. 1.2 Mya), followed by L. sechurae and then L. gymnocercus. The most internal group comprised L. griseus and the sister-species L. culpaeus and L. fulvipes, which diverged around 430,000 years ago in southern Argentina or Chile. The analysis of nuclear markers revealed several examples of intra-specific variation coupled with lack of species monophyly, consistent with pervasive incomplete lineage sorting and/or hybridization in this recent radiation. Our results provide robust mitochondrial resolution of this challenging radiation, and illustrate the difficulty of attaining similar success with traditional nuclear markers. [ABSTRACT FROM AUTHOR]

ABSTRACT Most aquatic mammals have high dispersal potential, and there are often severe conservation concerns related to their legal or illegal harvesting. Therefore, economic, social and forensic factors often arise in decisions relating to their population management. Molecular markers are essential tools in modern conservation genetics, revealing previously unknown aspects of aquatic mammal behaviour, natural history, population structure and demography. Molecular markers also have been used to define management units, to recognize taxonomic units, to conduct forensic analyses and to control illegal wildlife trade, providing valuable information for decision-making in wildlife conservation and management., We review studies published in peer-reviewed journals between 1993 and 2010, in which genetic approaches have been applied to conservation-related issues involving natural populations of 25 species of aquatic mammals in South America. These studies cover just 34% of the 70 aquatic mammal species recorded in South America., Most of the studies are related to population structure, phylogeography, gene flow and dispersal movements. In addition, recent findings relate to evolutionarily significant units, management units, forensics and conservation policy., Finally, we look to the future and, based on numbers of studies and conservation concerns, suggest which species, geographic areas and genetic studies should be prioritized. Moreover, we discuss constraints on research and suggest collaborative works that would provide critical information towards the effective conservation and management of aquatic mammals in South America. [ABSTRACT FROM AUTHOR]

The phylogeny and systematics of fur seals and sea lions (Otariidae) have long been studied with diverse data types, including an increasing amount of molecular data. However, only a few phylogenetic relationships have reached acceptance because of strong gene-tree species tree discordance. Divergence times estimates in the group also vary largely between studies. These uncertainties impeded the understanding of the biogeographical history of the group, such as when and how trans-equatorial dispersal and subsequent speciation events occurred. Here, we used high-coverage genome-wide sequencing for 14 of the 15 species of Otariidae to elucidate the phylogeny of the family and its bearing on the taxonomy and biogeographical history. Despite extreme topological discordance among gene trees, we found a fully supported species tree that agrees with the few well-accepted relationships and establishes monophyly of the genus Arctocephalus. Our data support a relatively recent trans-hemispheric dispersal at the base of a southern clade, which rapidly diversified into six major lineages between 3 and 2.5 Ma. Otaria diverged first, followed by Phocarctos and then four major lineages within Arctocephalus. However, we found Zalophus to be nonmonophyletic, with California (Zalophus californianus) and Steller sea lions (Eumetopias jubatus) grouping closer than the Galapagos sea lion (Zalophus wollebaeki) with evidence for introgression between the two genera. Overall, the high degree of genealogical discordance was best explained by incomplete lineage sorting resulting from quasi-simultaneous speciation within the southern clade with introgresssion playing a subordinate role in explaining the incongruence among and within prior phylogenetic studies of the family. [Hybridization; ILS; phylogenomics; Pleistocene; Pliocene; monophyly.] [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]

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]

Tear production and intraocular pressures (IOPs) were determined in 38 and 102 wild Humboldt penguins ( Spheniscus humboldti), respectively, from the Punta San Juan Marine Protected Area in Ica, Peru. Tear production was measured by Schirmer tear test, and IOP was measured with a TonoVet rebound tonometer. Adult (n = 90) and chick (n = 12) penguins were sampled from 2 different beaches (north and south facing) during 2 sampling years (2010 and 2011). Results showed a mean ± SD (range) of 9 ± 4 (2-20) mm/min for tear production and 28 ± 9 (3-49) mm Hg for IOP. Tear production in penguins differed between beach and sex, whereas IOP differed between age, year, and beach. The IOPs were negatively correlated with packed cell volume. Tear production and IOP values had greater variation in this population than it has in other avian species. Previous investigations of IOP and tear production in Spheniscus species were conducted with birds housed under professional care in artificial marine and freshwater environments. This is the first study, to our knowledge, investigating tear production and IOP in wild penguins and establishes valuable reference intervals for this species. [ABSTRACT FROM AUTHOR]