Claise Brook is a stream which empties into Claisebrook Cove before running into the Swan River in Perth, Western Australia. The area surrounding the stream is on the outskirts of the Perth CBD and is part of the suburb of East Perth. Claise Brook was once an important water course from which the numerous interconnected fresh water lakes north of Perth emptied into during the wet season before entering the Swan River.
Since the gradual resumption of land over the various feeder lakes, and more recently the East Perth redevelopment in the late 1980s, the stream has become a mainly underground catchment and drainage system and no longer exists as a stream in the normal sense.
The stream and cove were initially called Clause's Brook and Clause's Lagoon respectively, however these names appear to have been dropped soon after European settlement: an 1851 newspaper report spoke of the establishment of an abattoir at "Claise Brook". They were named after Frederick Clause who was a naval surgeon that accompanied Captain (later Admiral Sir) James Stirling in their expedition up the Swan River in March 1827. Botanist Charles Fraser who was on the same expedition described the lagoon in his journal:
"One mile up the river from the last point is a small creek of fresh water, issuing from an extensive lagoon clothed with arborescent species of Metrosideros of great beauty. The banks are covered with the most interesting plants, amongst which I observed two species of Calytris, a species of Acacia with a scolopendrous-stem, and several Papilionaceous plants. The Angophoras on the flats are gigantic."