Gollum Galaxias

FishNew Zealand

8 May

Galaxias gollumoides

Gollum galaxias — with their big eyes and flattened faces — are named for their resemblance to *The Hobbit* and *The Lord of the Rings* character. These 7-centimetre (2.8 in) fish live in the southern reaches of New Zealand and are considered 'critically endangered'.

New Zealand is basically Middle-earth. At least, it's where J.R.R. Tolkien's world was filmed for the big screen in the Lord of the Rings and Hobbit films, lending its dramatic mountains, rivers, and quaint hillsides to bring the fantasy books to life. You won't find wargs or trolls or ents in New Zealand, but down in the swampy reaches of the South Island, you will find a little creature with a flattened face and large bulbous eyes known as Gollum. It's not the corrupted character from Middle-earth — more like something he would snatch up and eat.

Gollums

A Gollum galaxias (*Galaxias gollumoides*).

These Gollums splash through slow streams, lurk in ponds and ditches, and hide between aquatic plants and debris. You might see one resting on an underwater rock or glimpse another leap above the surface and come down with an unimpressive splash — they are, after all, only some 7 centimetres (2.8 in) long. Their grey-green bodies glimmer with speckles of gold as they swim, propelled through the water with translucent fins and tails. They gaze about with dumb expressions, eyes massive in their blunt faces, searching for what they covet most: not a precious One Ring, but tasty may- and stonefly larvae.

These fish are known as galaxias — from the galaxy of shimmering stars that decorate their scaleless skin. Gollum galaxias, named for their less-than-stunning faces and swampy homes, live throughout the southern wetlands of the South Island. A Gollum's entire life — from a 2 millimetre egg to an adult with young of its own — is spent in fresh water. But, the species is also found on Rakiura (or Stewart Island), 30 kilometres (16 NM) south of the South Island, across the salty Foveaux Strait. The Rakiura Gollums were likely stranded there when the land bridge connecting Rakiura to the mainland was inundated 7,000 years ago, turning it into an island. Other galaxies, however, can, and do, make journeys out to sea.

Galaxias

Galaxias, or galaxiids, are found across the Southern Hemisphere. All 46 species are scaleless, most are some form of torpedo-shaped, and they range in size from the giant kōkopu, a New Zealand endemic which can grow to 58 cm (23 in) long and was the first galaxiid to be officially described, to species like the mountain galaxias of southeastern Australia, which is around 10 times smaller, measuring only 6 cm (2.4 in) long.

The Gollum is a non-migratory galaxiid, or, more technically, a non-diadromous one. A diadromous fish is, simply, a fish whose life cycle involves a migration between salt- and freshwater. The most famous of such migrations are performed by so-called anadromous fish; fish like salmon, which spend their lives at sea but migrate in vast processions to spawn in freshwater. Their opposites are catadromous fish; fish such as eels, that live in freshwater but journey to spawn in the salty water of the sea. Diadromous galaxias don’t migrate to breed; rather, they spawn in freshwater, and their larvae drift out to sea shortly after hatching. Spending part of their early lives in saltwater, they return to freshwater to grow, mature, and have young of their own.

The athletic abilities of any particular diadromous galaxiid species are apparent by how far inland, and how high up, the adults live. For example, common galaxias, or inangas, are not good climbers. These little fish lay thousands of eggs in vegetation along the banks of lowland streams and coastal lakes — the eggs, appearing like clusters of translucent pearls, sit out of water for up to two weeks as they await the next tide. Once re-soaked, they spawn and are swiftly swept to sea, where they'll live for 5 to 6 months before making the short journey inland. Common galaxias don't make it far past their spawning sites on their return trips, and the same is true for the largest of galaxias, giant kōkopu. Their homecomings require no great journeys.

Other galaxias are more accomplished travellers. Banded kōkopu are, for fish, fantastic climbers — juveniles trapped in a bucket are able to wriggle up the sides to escape. These acrobatic youngsters swim inland to tributary pools as high up as 550 metres (1,800 ft) above sea level. In contrast to the vast, open ocean from which they arrive, these pools are small and covered by canopies of vegetation — little worlds of dappled light and stillness where the travellers find homes far from the sea. Food, in the form of insects, falls from the foliage above, and the sensory organ atop a kōkopu's head alerts it to its next meal.

The kōaro are the great galaxiid voyagers. From their coastal kindergartens, they travel as far as 400 kilometres (250 mi) inland and reach elevations of 1,300 metres (4,265 ft). These fish, also known as climbing galaxias, can overcome almost any obstacle that lies along their course. With their large pectoral and pelvic fins, climbing galaxias cling to damp rocks and wriggle upwards inch by inch, ultimately scaling waterfalls tens of metres high. If Gollum galaxias are the homebody Hobbits of the Shire, then the kōaro are Bilbo, Frodo, and Sam — little souls undertaking great journeys across Middle-earth.

Common galaxias or inangas (*Galaxias maculatus*).

A climbing galaxias or kōaro (*Galaxias brevipinnis*).

Into Mordor

New Zealand whitebait consists of the juveniles of six fish species — five of which are galaxiids.

All of the diadromous galaxias we've just met — from the coastal common galaxias to the mountaineering climbing galaxias — comprise New Zealand's 'whitebait' (along with the shortjaw kōkopu, another galaxiid, and the common smelt). Whitebait is a collective term for juvenile fish that, in New Zealand, swim upstream from the sea in mixed-species congregations every spring. Whitebaiting is the act of catching these migrating young fry. In the past, whitebait was scooped from the rivers en masse, collected in such large numbers that it was fed to chickens and used as fertiliser. Today, these immature white fish can only be caught during whitebaiting season within a limited time window each day (the fish are mostly nocturnal, and fishing is only allowed during the day). They are then sold as an expensive delicacy, typically eaten in fritters.

It wasn't just extreme levels of fishing that depleted the whitebait population. Even those juveniles who avoided being caught and made it to their freshwater homes found fragmented habitats or waters poisoned by pollution. The non-migratory galaxiids have it just as bad, if not worse. There are 12 known species of non-migratory galaxiids in New Zealand, with many being difficult to tell apart (thus why there are another 13 recognised, but indeterminate taxa). Many of these species have highly fragmented populations, leading to a high rate of local extinctions as small, isolated pockets of fish are wiped out. Livestock are given access to streams, trampling the banks and eating native vegetation — where many galaxias lay their eggs — while invaders like trout voraciously dine on galaxiids, and deforestation changes the flows of waterways, fragments populations, increases sedimentation, and destroys spawning areas.

Gollum galaxias live across a wide range of habitats — from lowland swamps near the sea to streams that flow 1,100 metres (3,600 ft) above sea level. By all metrics, these are adaptable fish. They're also considered 'Threatened – Nationally Vulnerable' and, on a global scale, 'Critically Endangered', with their populations decreasing.

While they may be marching into Mordor, they haven't tumbled into Mount Doom just yet. If you live in New Zealand, you can help both migratory and non-migratory galaxiids from going the way of Gollum and the One Ring.

**Where Does It Live?**

⛰️ Slow streams, marshes, ponds, and ditches; up to 1,100 metres (3,600 ft) above sea level.
📍 In the south of New Zealand’s South Island and on Rakiura/Stewart Island. ¹

Size // Tiny
Length // 7 cm (2.8 in)
Weight // N/A
Activity: Nocturnal 🌙
Lifestyle: Social 👥
Lifespan: N/A
Diet: Carnivore (Insectivore)
Favorite Food: May- and stonefly larvae
Class: Actinopterygii
Order: Galaxiiformes
Family: Galaxiidae
Genus: Galaxias
Species: G. gollumoides

Gollum galaxias live across a wide range of habitats — from lowland swamps near the sea to streams that flow 1,100 metres (3,600 ft) above sea level.
What this Gollum fish covets most isn't its precious One Ring, but tasty may- and stonefly larvae.

This fish is not only found in the southern swamps and waterways of New Zealand's South Island, but also some 30 kilometres (16 NM) offshore, on Rakiura (or Stewart Island). Given that this is a freshwater fish, the Rakiura Gollums were likely stranded when the land bridge connecting Rakiura to the mainland was inundated 7,000 years ago, turning it into an island.
Threatened by an increase in sedimentation, habitat fragmentation, pollution, and invasive species, the Gollum galaxias is considered 'Threatened – Nationally Vulnerable' and, on a global scale, 'critically endangered'.

The Gollum is one of 46 species of galaxias found across the Southern Hemisphere. They range in size from the giant kōkopu, a New Zealand endemic which can grow to 58 cm (23 in) long, to the mountain galaxias of southeastern Australia, which is around 10 times smaller, measuring only 6 cm (2.4 in) long.

The Gollum is a non-migratory galaxiid. Migratory species spawn in freshwater, and their larvae drift out to sea shortly after hatching. After spending part of their early lives in saltwater, the young fish return to live in freshwater.

Different galaxiids are variously inclined towards travel and athletics:
- Common galaxias must only make short trips back to their lowland streams from the sea.
- Banded kōkopu — fantastic climbers (for fish), with juveniles trapped in a bucket able to wriggle up the sides to escape — swim to inland pools as high up as 550 metres (1,800 ft) above sea level.
- The kōaro are the great galaxiid voyagers. They travel as far as 400 kilometres (250 mi) inland and reach elevations of 1,300 metres (4,265 ft) — scaling waterfalls tens of metres high.