Gollum galaxias

Appearance

Its dorsal and anal fins have a short base but are high and rounded with long middle rays. The start of its anal fin is a little behind the origin of its dorsal fin. Additionally, it has a short, blunt snout, with a mouth reaching back to just below the center of its eyes.

Its upper and lower jaw are approximately equal in length, and it possesses enlarged canines on both the upper and lower jaws. Another distinguishing characteristic that it shares only with Galaxias anomalus, is having an eye diameter greater than 23% of the head length.

Range and habitat

Individuals are present in both wetland and stream habitats. Individuals from streams are most often found in regions with a lot of instream cover and are commonly found among moss, woody debris, and vegetated banks. Habitat substrates range from sand with layers of algae to deep layers of liquid silt to bedrock and coarse granite sand.

The species is widespread in rivers throughout the Southland Plains as well as the Von River and Nevis River tributaries of the Clutha River The species is found on Stewart Island / Rakiura, and throughout the Catlins.

Pins are Wikidata “endemic to” fields. Orange dots, when present, are GBIF occurrence tiles — survey bias included.

Breeding

The species has additionally been observed resting on top of stones and spawning substrate, often in groups, but quickly retreats to covered positions when disturbed. As a non-diadromous species, G. Gollumoides reproduce and live in freshwater habitats and no migratory behavior has been observed in the species within these habitats.

The species spawns in both fast-flowing streams with cobble substrate as well as in wetland habitats with silt substrate and marginal vegetation. Spawning generally occurs on a single day but some instances of partial spawning have been recorded, with females gradually releasing all their eggs over a multi-day period. The majority of spawning in the species occurs late August to early September with females laying eggs and males externally fertilizing the eggs.

In crisis

Gollum galaxias is classified as threatened in the New Zealand Threat Classification System, with the further qualifiers of “Nationally Vulnerable” and the stipulation that there is poor data for this species. Predation by introduced salmonids significantly contributes to their conservation status and their limited population Additionally, factors such as habitat loss from development, declining water quality from pollutants like fertilizer runoff, and modifications to rivers all contribute to the decline of freshwater galaxiids in New Zealand.

Gollum galaxias is Critically Endangered on this catalog because that is the IUCN category stored on Wikidata. Confirm the official criteria and any later count on iucnredlist.org.

Sources

Written for this catalog from the English Wikipedia article on Gollum galaxias, Wikidata item Q44182. Family and order context is original field-guide writing about the group, not a copied assessment of this one species. Wikipedia text is CC BY-SA. Not an IUCN assessment. Counts, when quoted, can change — confirm them on the recovery programme and on iucnredlist.org.