Lower marine productivity increases agonistic interactions between sea lions and fur seals in Northern Pacific Patagonia

Interspecific interactions are key drivers of individual and population-level fitness in a wide range of animals.However,in marine ecosystems,it is relatively unknown which biotic and abiotic factors impact behavioral interactions between competing species.We assessed the impact of weather,marine productivity,and population structure on the behavioral agonistic interactions between South American fur seals(SAFSs),Arctocephalus australis,and South American sea lions(SASLs),Otaria byronia,in a breeding colony of SAFS.We hypothesized that agonistic interactions between SAFSs and SASLs respond to biotic and abiotic factors such as SAFS population structure,marine productivity,and weather.We found that SASL and SAFS interactions almost always resulted in negative impacts on the social structure or reproductive success of the SAFS colony.SASL adult males initiated stampedes of SAFS and/or abducted and predated SAFS pups.Adult SAFS males abundance and severe weather events were negatively correlated with agonistic interactions between species.However,proxies for lower marine productivity such as higher sea surface temperature and lower catches of demerso-pelagic fish were the most important predictors of more frequent agonistic interactions between SAFS and SASL.Under the current scenario of decline in marine biomass due to global climate change and overfishing,agonistic interactions between competing marine predators could increase and exacerbate the negative impacts of environmental change in these species.

Fur Seal Feces-Associated Circular DNA Virus Identified in Pigs in Anhui, China

Fur seal feces-associated circular DNA virus(FSfa CV)is an unclassified circular replication-associated protein(Rep)-encoding single-stranded(CRESS)DNA virus that has been detected in mammals(fur seals and pigs).The biology and epidemiology of the virus remain largely unknown.To investigate the virus diversity among pigs in Anhui Province,China,we pooled 600 nasal samples in 2017 and detected viruses using viral metagenomic methods.From the assembled contigs,12 showed notably high nucleotide acid sequence similarities to the genome sequences of FSfa CVs.Based on these sequences,a full-length genome sequence of the virus was then obtained using overlapping PCR and sequencing,and the virus was designated as FSfa CV-CHN(Gen Bank No.MK462122).This virus shared 91.3%and 90.9%genome-wide nucleotide sequence similarities with the New Zealand fur seal strain FSfa CV-as50 and the Japanese pig strain FSfa CVJPN1,respectively.It also clustered with the two previously identified FSfa CVs in a unique branch in the phylogenetic tree based on the open reading frame 2(ORF2),Rep-coding gene,and the genome of the reference CRESS DNA viruses.Further epidemiological investigation using samples collected in 2018 showed that the overall positive rate for the virus was 56.4%(111/197)in Anhui Province.This is the first report of FSfa CVs identified in pigs in China,and further epidemiological studies are warranted to evaluate the influence of the virus on pigs.