Lake Onega is relatively cold, with temperatures below for half of the year and average summer temperatures of about . The catchment area of drains into the lake via 58 rivers and more than 110 tributaries, including the Shuya, Suna, Vodla, Vytegra and Andoma. The only outgoing River Svir, which marks the southern boundary of Karelia, runs from the southwestern shore of Lake Onega to Lake Ladoga and continues as the Neva River to the Gulf of Finland. The White Sea–Baltic Canal runs through the lake from the White Sea to the Baltic Sea. The Volga–Baltic Waterway connects Onega Lake with the
Salinas of the English Port loggerhead sea turtle ("Caretta caretta"). It hosts characteristic sand dune and wetland birds, including the greater hoopoe-lark ("Alaemon alaudipes"), the black-crowned sparrow lark ("Eremopterix nigriceps"), bar-tailed lark ("Ammomanes cinctura"), the sanderling ("Calidris alba") and the bar-tailed godwit ("Limosa lapponica"). It also has an important population of the Kentish plover: 50% of the total population of Cape Verde (150-300 individuals). Salinas of the English Port Salinas of the English Port () is a saline wetland in the southwestern part of the island of Maio, Cape Verde, northwest of the city Porto Inglês. It is a protected area ("Paisagem Protegida das Salinas