Resource partitioning can contribute to species coexistence by redudcing interspecific competition. To understand whether resource partitioning contributes towards sympatric populations of two otariids in Peru's dynamic Humboldt Current System (HCS), we compared seasonal diet composition of South American fur seals (SAFS, Actocephalus australis) and South American sea lions (SASL., Otaria byronia) over 15 seasons between 2015 and 2018 to determine whether there is a detectable mechanisms for resource partitioning at population level. Diet composition was estimated from identification of hard remains of prey items obtained from 3325 scats colected from rookcries at Punta San Juan, Peru...