Kendrick, T.H.; Bentley, N. (2004). Movements of rock lobsters ( Jasus edwardsii ) tagged by commercial fishers around the coast of New Zealand from 1993.

 New Zealand Fisheries Assessment Report 2004/yy. Xx p .

Since 1993–94, rock lobster fishers around New Zealand have released over 80 000 tagged lobsters ( Jasus edwardsii ) . The primary purpose of these tagging programmes was to provide information on growth rates for stock assessments. However, many release and recapture records include accurate release and recapture position coordinates. The movements of these lobsters are summarised and described.

Movements around most of New Zealand were generally small with most individuals recaptured within 5 km of their release site: 89% of recoveries from CRA 2, 94% from CRA 3, 98% from CRA 4, 92% from CRA 5 and 59% from CRA 8 represented movements of less than 5 km. The nature of these short-distance movements is not investigated or described in any detail and is assumed to mainly relate to foraging behaviour. Longer-distance movements (over 5 km) are described for all the main tagging areas. The proportion that had moved more than 5 km varied markedly among areas but may in large part be accounted for by differences in size at onset of maturity around the country, which determines the degree to which commercial pots retain immature lobsters.

Tag recoveries from a southern fishstock, CRA 8, are described in greater detail, in the context of previous movement studies, with much higher proportions of lobsters demonstrated to have moved than previously reported. These analyses confirm patterns previously described and give evidence of a further aspect of the large-scale movement; a seasonal inshore-offshore movement of mature females on the Fiordland coast, out to the reef edge at the end of the egg-bearing period, presumably to release newly hatched larvae into the stronger currents of deep water. Similar behaviour has been observed by divers in other parts of the country and is suspected to be widespread, but has been difficult to demonstrate as it is best studied by constant tracking. The horizontal distances moved may be small, and the pattern is detected only by a seasonal movement through depth. This pattern of movement probably explains the seasonal ‘homing' behaviour previously observed in large females, and helps to confirm the purpose of the large-scale, long-distance migrations of immature females and small males, described in several studies of the south coast of New Zealand since 1969.

The two patterns of movement described in detail for the southern fishstock CRA 8 are migrations of different kinds. The first is a long-distance, one-way migration of immature rock lobsters, the second is an annual inshore-offshore cycle that occurs at the destination and involves mature egg-bearing females.