| Remarks |
Ocean jackets are found from very shallow water (2 m) to water as deep as 200 m. There is a tendency for their average size to increase with waters depth (Ref. 30465). Juvenile ocean jackets have been caught in seagrass, over bare sand and on rocky reefs (Ref. 6390). Adults however, tend to be absent from seagrass areas (Ref. 6390). In northern New South Wales, ocean jackets are occasionally present in reef areas, but in South Australian waters, they are common over sand and 'coral' (bryozoans - Ectoprocta) sea beds (Ref. 6390).
Seasonal migration in South Australia appears to be associated with spawning: movement is predominantly to the west prior to spawning, and to the east just after spawning (Ref. 6390). Tagging studies conducted in this region have recorded movements by individual ocean jackets of up to 350 nautical miles along the continental shelf over a 12 month period (Ref. 6390).
In South Australian waters, the generally south-westerly direction of winter surface currents in the eastern Great Australian Bight possibly facilitates the inshore movement of ocean jacket larvae from the offshore spawning areas. Juvenile ocean jackets averaging 12 cm TL first appear in the gulfs and sheltered bays and inshore coastal waters in November, ie at approximately 6 months of age (Ref. 30466). In May and June, when they are about 1-year-old, young ocean jackets begin to move out of inshore areas to more open waters up to about 60 m depth. This general offshore migration continues with age, such that older fish inhabit the deepest waters at the edge of the continental shelf (Ref. 6390). |