Movements
For management, the most important movements are large-scale migrations or inshore-offshore movements.
Extensive tagging of J. edwardsii has been conducted in many areas. In most areas fewer than 5% of the returns have moved more than 5 km. Areas with this movement pattern include Tauroa Point, Banks Peninsula, Gisborne, Wellington, and Fiordland.
Southern movement patterns
Movement patterns in southern New Zealand appear to involve two groups of animals:
- ‘Run’ rock lobsters that migrate over long distances
- ‘Resident’ rock lobsters that do not.
In most studies, less than 4% of tagged lobsters moved significantly from the release site. However, when ‘run’ lobsters were tagged, between 27.6% and 38.6% recaptures showed long-distance movements.
The long-distance movements of J. edwardsii tagged in southern New Zealand tend to be directional:
- Southward along the Otago coast and the east coast of Stewart Island
- Westward through Foveaux Strait
- Northward along the west coast of Stewart Island and the Fiordland coast.
These movements are in opposition to the prevailing current systems.
Migrating females
Most migrating females are immature. They move from Otago and Foveaux Strait (where lobsters have a large size at 50% maturity) to Fiordland (where lobsters are a smaller size at 50% maturity).
These movements may be a ‘contranatant migration’ in which animals migrate against the current that carries the larvae.
Timing
Movements appear to be seasonal, usually occurring off the Otago coast and through Foveaux Strait from September through November, and along the Fiordland coast during November through January.
Northern movement patterns
The long-distance movements of S. verreauxi in northern New Zealand also appear directional. All but two recaptures tagged at North Cape moved to the west or southwest, most to near Cape Reinga.
Of the female recaptures, only 10% were mature when tagged, but 80% were mature when recaptured. Only 10% of the females tagged at North Cape had setae on the pleopods, but 80% had setae when recaptured. This may be another contranatant migration, with nearly mature juveniles located near North Cape moving towards Cape Reinga, where the only large breeding population of this species is known.
There may also be a return movement by juvenile S. verreauxi along the east coast of the North Island towards the north, against the prevailing current system. Most of the sublegal lobsters and immature females tagged between Bream Bay and Mahia moved north or west before recapture.
Large numbers of sublegal animals are found on the east coast, south of North Cape. However some legal-sized mature females are also found in this area. Thus juveniles from this area may also move towards Cape Reinga just before reachng sexual maturity.