Background
Lord Howe Island, and the adjacent Balls Pyramid to the south, lie
630 km east of the NSW coast and are the most southerly volcanic
seamounts in a chain of nine stretching 1000kms to the north (Hayes and
Ringis 1973). The island was first settled in the early 1800s and has
since experienced substantial, and in instances lethal, impacts on its
terrestrial flora and fauna (James 1995). This has not occurred in the
marine environment, which is recognised as complex and regionally
unique. The Lord Howe Island Marine Park (Commonwealth Waters) covers an
area of 300,000 hectares and extends between the NSW State Marine Park
Boundary and 12 nm offshore. This effectively covers the extent of the
shelf and depths to 1800m. In 1982, the islands and surrounding rocky
outcrops were added to the World Heritage List, and these were
subsequently encompassed by the State and Commonwealth Marine Parks
(proclaimed June 2000) (Lord Howe Island Marine Park (Commonwealth
Waters) Management Plan 2002) (see Figure. 1).
Because of its subtropical location and the seasonal excursions of
the East Australian Current (Boland and Church 1981), mean seawater
temperatures can fluctuate between 18 and 23°C (Veron and Done 1979).
These waters support a fringing coral reef on the limit of conditions
under which such a structure can survive, and while the intrinsic value
of this is clearly recognised and been extensively researched, there is
limited information on the habitats and occupants of the deeper shelf
waters representing the major portion of the park. A previous assessment
concluded that “..there is a possibility of existence, particularly for
the benthos, of new species and species of particular evolutionary or
biogeographic importance and significance” (Pichon 1995).
The main uses of the sub-tidal waters of the marine park are tourism
and fishing. Islanders and the operators of fishing charters take a
variety of fish species for local consumption. With the advent of GPS
navigation devices and depth sounders, the charter operators have moved
offshore to exploit the deeper water of the shelf break with droplines
and metal jigs. With the decline in yellowfin tuna numbers close to the
mainland there has been an increase in traffic of domestic longliners in
the East Coast Tuna and Billfish Fishery near Lord Howe Island. There
are unconfirmed reports that they sometimes take slimy mackerel for bait
and set longlines for tuna and swordfish near the Island.
Current Knowledge
This study is the first effort to characterise the deeper water
habitats surrounding Lord Howe and Balls Pyramid. Substantial
information exists for shallower habitats accessible to SCUBA diving and
comprehensive species lists are available for fish (Francis 1993, Allen
et al 1976), corals (Harriott et al. 1995) and algae (Millar and Kraft
1993, 1994a,b). A review of specimens at the Australian Museum from the
deeper shelf waters indicates a relatively high level of endemism
(13.1%), higher than the level for the shallow waters (Ponder et al.
2000). Collections of flora and fauna from other seamounts on the Lord
Howe Rise indicate a similar contribution by endemics and these deeper
water habitats are considered rich and diverse (Roberts et al. 2002,
Rogers 1994).
Figure
1. Map showing the location of the Lord Howe Island and Balls
Pyramid Rises with the jurisdictional boundaries and the
Commonwealth Marine Park Sanctuary Zones. (Image reproduced courtesy
of DEH).
