Biological Environment of the West Coast Coastal Marine Area: an outline of Marine and Coastal Ecosystems and Habitats
3.2 Plant and Animal Species
The West Coast marine and coastal biological environment contains a variety of plant and animal species living in the variety of ecosystems described in Chapter 2. The main groups of species that occur here include:
- Marine mammals;
- Birds;
- Fish;
- Invertebrates;
- Plants – Seaweeds and vascular; and
- Plankton.
This overview section only summarises the features of these broad species groups. However, some individual species and species assemblages are discussed elsewhere in this chapter within their preferred environmental domain.
Mammals
Marine mammals are among the biggest and most noticeable of marine animals.
At least 21 species (12 whales, six dolphins and three seals) have been reported
from the West Coast1, including 11 threatened species2.
Most feed on a variety of small fish and squid, but the large baleen whales
(e.g. minke, southern right and blue whales) are plankton feeders. Two of
the most obvious and well-studied marine mammals on the West Coast are the
New Zealand fur seal and the Hector’s dolphin.
New Zealand fur seals have a fluctuating West Coast population estimated at
about 12 500 mature animals3. Fur seals regularly
come ashore to rest at more than 20 ‘haul-out’ sites on the West
Coast, and breed in at least seven of these4. They
travel widely within and beyond the region, feeding on fish and squid.
Hector’s dolphins are a threatened species found only in New Zealand,
with about 5400 (three quarters of the total population) on the West Coast5.
They live in nearshore waters mostly shallower than about 70 metres, and in
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| Hecror's dolphin (aihe) and NZ fur seals (kekeno) are two of the most obvious marine mammals on the West Coast. Photos: DOC Collection. |
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Birds
A full inventory of the West Coast’s coastal and marine birdlife has
not been compiled, but they have been recorded from all environmental domains
and include at least 18 threatened species6.
Seabirds such as albatrosses, petrels, shearwaters and gannets occur in the
open sea, feeding on small fish and other species, and often congregating
around fishing boats for an opportunistic feed. Some seabirds nest on the
coast, such as Westland petrels near Barrytown, and fairy prions and sooty
shearwaters on a few of the islands, rock stacks and headlands that provide
refuge from predatory animals. The threatened tawaki (Fiordland crested penguins)
have important nesting areas in South Westland coastal forests, and feed near
the edge of the continental shelf7. Blue penguins
have more dispersed nesting areas along the region’s coastline8.
Shorebirds (e.g. gulls, terns, oystercatchers and dotterels) live on beaches, estuaries and rocky shores, while wading birds and waterfowl (e.g. godwits, stilts, herons, crakes, ducks and swans) depend on estuarine tidal flats, saltmarsh and channels for their roosting areas and food sources of small fish, shellfish and other invertebrates.
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| Westland Petrel (taiko). Photo: DOC Collection. |
Tawaki (Fiordland crested penguin). Photo: P Ryan, DOC Collection |
Variable oystercatcher (torea) Photo: D. Neale, DOC |
Fish
West Coast fish species vary widely in their size (from the 3 cm-long pygmy
sleeper to the 9 metre basking shark), diet (including seaweeds, invertebrates
and other fish) and habits (e.g. nocturnal or diurnal, freshwater or marine,
demersal or pelagic). Surveys on the West Coast have recorded at least 90
species from the nearshore shelf environment9 and
86 coastal reef and estuarine fish10, including nine
threatened species.
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| Shortfinned eels (tuna). Photo: S. Moore, DOC Collection |
Sea perch (pohuiakaroa). Photo: P. Ryan, DOC Collection |
Invertebrates
West Coast invertebrates (animals without backbones) include at least ten
phyla (major taxonomic groups). A full inventory of species has not been attempted,
but they number at least in the hundreds11. Some
of the main groups found on the West Coast are molluscs (e.g. shellfish, octopus
and squid), arthropods (e.g. crabs, lobsters and hoppers), sponges, seasquirts,
echinoderms (e.g. starfish and kina) and bryozoans. The only invertebrate
species protected under the Wildlife Act is black coral.
Some of the many kinds of invertebrates which occur in the West Coast marine environment.
Top row: Jellyfish; Red rock lobster; Anemone
Second row: Zooanthids; Sponges; Seven armed star
Third row: Octopus; Snakestail star; Shrimp
Bottom row: Kina and seaweeds; Biscuit star; Cancer crab
Photos: Paddy Ryan, DOC Collection
Plants
Seaweeds (a group of marine algae that attach to rocks or shells) occur mostly
on intertidal and shallow subtidal reefs, as well as some estuarine environments.
Surveys have recorded at least 175 species of seaweed from the West Coast12.
Bull kelp is the most obvious of these, but others including smaller ‘turfing’
and ‘encrusting’ species also occur there, providing food and
shelter for many invertebrates and fish.
Vascular plants such as saltmarsh plants, coastal herbs, shrubs and trees
occur in intertidal estuarine environments and on the coastal margins of sand
dunes, wetlands and hillslopes. At least four of these species are regarded
as threatened13.
Top: Turfing seaweeds
Bottom row: Oak leaf seaweed; Turfing seaweeds centre and right
Photos: N. Shears
| Plankton Plankton is a diverse group of free-swimming biota near the sea surface that can ‘bloom’ in large masses under some sea conditions, ranging from microscopic single-celled plants and animals, to the young larval stages of larger fish, crabs and other species. The plankton on the West Coast has been studied in relation to the region’s current patterns and the upwelling of nutrients from the deeper seabed, and their contribution to the marine foodweb of the region’s fish stocks and other biota14. |
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Photo: P. Ryan, DOC Collection
Some other marine invertebrates:
A. Sea squirts;
B. Jewel anemones;
C. Hydroid colony
D. Reef star
Photos: Paddy Ryan, DOC Collection
1 Neale 2005
2 Hitchmough et al 2007, see Appendix 4
3 Best 1998
4 Neale & Best 1999
5 Slooten et al 2002
6 Hitchmough et al 2007, see Appendix 4
7 McLean et al 1997
8 Hughes 2005
9 Stevenson 2002
10 Roberts et al 2005
12 Neale & Nelson 1998
13 Hitchmough et al 2007, see Appendix 4
14 e.g. Bradford 1991, Bradford 1985, Chang & Bradford 1985, Bradford
& Roberts 1978