[1] The catchment area is over 8,000 square kilometres (3,089 sq mi) but is ephemeral and only flows in the wet season, during the dry it is a series of pools and billabongs.

[5] The Mary River floodplains form a vital habitat in the dry season for some 250 species of birds including jabiru, jacana, brolga and pygmy geese.

[6] Four threatened plants are found along the river including Goodenia quadrifida, Schoutenia ovata and the endangered Cycas armstrongii and Helicteres macrothrix.

[7] The riparian vegetation found on the upper catchment includes mixed woodlands of pandanus, wattle, paperbark and freshwater mangroves with an understorey of grass and sedges.

[2] 34 species of fish are found in the river, including the Macleay's glassfish, barred grunter, sooty grunter, fly-specked hardyhead, toothless catfish, flathead goby, spangled perch, barramundi, oxeye herring, rainbowfish, black-banded rainbowfish, northern trout gudgeon, bony bream, catfish, Hyrtl's tandan, freshwater longtom, seven-spot archerfish and the sleepy cod.