A Rare Handfish Appeared on Camera. Its Exact Species Was Less Certain.

A small fish on the seabed gave a research team something they hadn't expected to see. During a July 2023 voyage off southeastern Australia, a camera photographed what scientists believed could be a narrowbody handfish, a species last recorded in 1996.

The sighting came northeast of Tasmania's Flinders Island, 292 metres below the surface, or about 958 feet. In its August 2023 account, CSIRO described the excitement of finding the animal and the uncertainty that remained over its exact identity.

Finding the Fish in the Images

The photographs came from a deep tow camera aboard RV Investigator during the South-East Australian Marine Ecosystem Survey, known as SEA-MES. Marine ecologist Candice Untiedt noticed the handfish shape in the images and had handfish specialist Carlie Devine aboard to help assess it.

This wasn't a fish brought up for examination. Researchers were looking at images from the seabed. That let them recognise a handfish, but it limited how far they could go with the identification. The suspected narrowbody handfish was larger than the two specimens they already had on record and was photographed about 100 kilometres outside its known location.

Why the Species Name Needed Care

The proposed name was Pezichthys compressus. CSIRO had first discovered the narrowbody handfish in 1986, and its Australian National Fish Collection held just two specimens. Its previous recorded sighting was in 1996, more than a quarter of a century before the voyage.

Devine told ABC that confirming the species would require a specimen so researchers could inspect its identifying features. Depth and location made narrowbody handfish a possibility, rather than a certainty. The photograph added a valuable observation without settling that question. Calling it a confirmed rediscovery would go beyond what the team could establish from the camera images.

Another Handfish Project Was Underway

Handfish get their familiar name from fins that resemble little limbs on the seabed. CSIRO's 2023 account described 14 species, seven found only around Tasmania and Bass Strait.

Before the voyage, Devine had collected 20 spotted handfish for a captive breeding program. Those were Brachionichthys hirsutus, a different species from the suspected narrowbody fish in the camera image. The team hoped the captive fish would breed so juveniles could later be released.

A Survey With More to Find

SEA-MES repeated surveys of southeastern Australian waters to examine changes in fisheries and marine parks. The handfish appeared during that wider work, rather than a voyage devoted solely to finding it.

The team also recovered an intact pyrosome in Freycinet Marine Park. A pyrosome is a colony of small animals forming a tube or cone, not one large fish. Chief scientist Rich Little noted that researchers more often encountered broken pieces in their nets.

Camera records and collected specimens gave the voyage different kinds of evidence. For the handfish, the image was a rare glimpse with an identification still to confirm.