BIO 203



Australia is known for having many lethal animals, which makes the Carukia barnesi right at home in the land down under! The Irukandji are native to Australia's marine environment. They inhabit the northern, costal waters from Broome on the western side to Rockhampton on the eastern side (Kingsford, et. al 2012). The Great Barrier Reef, larger cities, and tourist attractions (such as Cairns, Whitsunday Islands, and Mackay), are included in this region. The map below displays these cities and landmarks.

Wikimedia Commons: Cookaa

Carukia barnesi typically inhabit deeper waters (between 10-20 meters/33-66 feet) farther off-shore (Ruzi and Patel 2012). This is considered the Irukandji's niche. A niche is a temporal or geographical position or location in which an organism commonly resides due to competition for food and/or space, availability of food, or to avoid/exist with other organisms. C. barnesi most likely remains at this depth because another box jellyfish, Chironex fleckeri, inhabits the same regional waters, only closer to the surface. However, Irukandjis have been found at the water's surface and closer to shore due to the currents washing them to shallow waters and beaches. 

Map made by Kelsey Lyons


Between December and February in 2007-2008, 2008-2009, and 2009-2010, Kingsford, Seymour, and O’Callahgan observed the abundance patterns of cubozoans in the Great Barrier Reef area. Over the three years, they collected, identified, and then released jellyfish directly offshore, in bays, next to islands, and around the reefs both during the day and at night. Carukia barnesi was included in the 40-50 cubozoan species for which they collected data. Their findings state that the Irukandji were most frequently found in groups around islands with high concentrations of granite, such as Lizard Island (on the map above). It is unknown why this occurs and more censuses must be taken to ensure that this data is reliable regarding the places of frequency and variables than can alter the abundance of these jellies. Different variables that can affect this habitat can be found on the bottom of this page.  


This region is a very diverse and amazing habitat. Along with Carukia barnesi, the Great Barrier Reef alone has 1,500 tropical fish species, 400 coral species, and 20 reptile species.  Also, an incredible 10% of the entire world’s fish population inhabits the Reef (Quicksilver 2013).  

Wikimedia Commons User: Richard Ling


Some factors that affect the Irukandji's home include sunlight, temperature, rainfall, and salinity. This costal/reef biome is characterized by a large amount of sunlight and consists of only two seasons:

    May-October: Warm temperature with little rainfall
    November-April: High temperature with a lot of rainfall

The water temperature ranges from an average of 23C (73.4F) in July to an average of 29C (84.2F) in February (Travel Online 2013).

Salinity if a major factor in the reef habitats and averages 35 parts/1000 in northern Australian waters (Kohli 2013). If the salinity abruptly changes, usually due to extreme rainfall or flooding from fresh bodies of water, many marine organisms can be negatively impacted (Great Barrier Reef Marine Park Authority 2009)


                                    Next stop: Adaptation



Last Updated: April 26, 2013

Wikimedia Commons: Peter Southwood Wikimedia Commons: GondwanaGirl Wikimedia Commons: Zaneta Nemcokova