Story: Oceanic fish

Page 4. Moonfish, flying fish, sunfish and mid-water species

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Moonfish

These vibrantly coloured fish are found in oceanic waters of warm and temperate regions. They are usually only seen in northern New Zealand when cast up on beaches. Often caught unintentionally by offshore boats fishing for bigeye tuna, they are sold commercially.

The main species in New Zealand waters is Lampris guttatus, a round, flat fish which can grow to 1.5 metres in diameter. The related opah (Lampris immaculatus) is also occasionally caught.

Flying fish

Flying fish have enlarged pectoral fins that help them to escape from predators. The fish breaks through the water surface at high speed and its fins act like wings, enabling it to glide over the water for up to 50 metres. They are often sighted by yacht crews, and sometimes land on deck.

About 120–380 millimetres long, they feed on plankton and crustaceans just below the surface. At least five species occur in offshore surface waters around northern New Zealand.

Sunfish

The huge sunfish (Mola mola), which can reach 3 metres long, feeds with its tiny mouth on soft-bodied plankton (salps and jellyfish). This bizarre creature resembles a squashed rugby ball with twin rudders – these are its fins, which swish in a figure-of-eight movement, stabilised by the large tail. Although it does not look agile, the sunfish can leap above the water. If one swims near the surface, its fin is sometimes mistaken for that of a shark.

This seasonal visitor moves into northern New Zealand waters from November to late June. Stragglers reach as far south as Otago Peninsula. Although they are often seen alone, they may also congregate.

Mid-water species

Several species living in the mid-water zone (100–500 metres deep) frequent New Zealand waters.

Saury

Saury (Scomberesox saurus) are common in the temperate seas off northern New Zealand. They are about 350 millimetres long and eat small crustaceans and fish.

Dolphinfish

Dolphinfish are tropical fish found worldwide in the open ocean. They do not look much like dolphins, as they have a large blunt head.

The species known in New Zealand is the mahi mahi (Coryphaena hippurus), occasionally seen off northern shores. They are about 1–2 metres long and feed on large fish.

Warehou

The warehou family has about 20 species, common in New Zealand waters. They are also known as raft fish, as they are often found with drifting debris. They often have short, blunt heads, and they feed on jellyfish and plankton.

The blue warehou (Seriolella brama) is commonly found around Cook Strait and the South Island, but is rare further north. The silver warehou (Seriolella punctata) is found around most of New Zealand, but is a deeper-water species. They are typically 40–60 centimetres long.

Pomfret

Pomfret live in tropical to temperate oceans. New Zealand has at least six species, although they are rarely seen. They are Ray’s bream (Brama brama), southern bream (Brama australis), bigscale pomfret (Taractichthys longipinnis), spiny pomfret (Pterycombus petersii), Taractes asper and wingfish (Pteraclis velifera).

Pomfret are about 600 millimetres long, and mainly eat shrimps and small fish. Ray’s bream is occasionally taken in commercial quantities.

Bonnetmouth

The red bonnetmouth is about 200 to 400 millimetres long, with a deeply forked tail and jaws that open up like a car bonnet. The two species found in New Zealand are the rubyfish (Plagiogeneion rubiginosum) and redbait (Emmelicthys nitidus). They feed on plankton.

Bluenose

The bluenose (Hyperoglyphe antarctica) is widely distributed around New Zealand, usually near rough seafloor. They feed on fish, crustaceans and small squid. They are an important commercial species, and catches increased rapidly from around 1980. They grow to 30–45 centimetres in length.

Acknowledgements to Malcolm Francis.

How to cite this page:

Carl Walrond, 'Oceanic fish - Moonfish, flying fish, sunfish and mid-water species', Te Ara - the Encyclopedia of New Zealand, http://www.TeAra.govt.nz/en/oceanic-fish/page-4 (accessed 18 November 2019)

Story by Carl Walrond, published 12 Jun 2006