Deep Discoveries

To find fishy new species in the Tasman Sea, an Academy ichthyologist searched the deep ocean floor.

In the deep waters between Australia and New Zealand, giant sea spiders and armored shrimp take up residence alongside schools of small, spiky sharks and bottom-walking coffinfish that attract prey with built-in, glowing lures. Each of these unusual groups includes species that were unknown to science until this past May, when a team of scientists from Australia, New Zealand, and several other countries trawled the ocean floor around Lord Howe and Norfolk Islands to document the area's deep-sea biodiversity. Academy ichthyologist Tomio Iwamoto joined this international team to search for new specimens from a group of deep-sea fishes called grenadiers, or rattails, which are related to codfish.

Aboard a research vessel for four weeks, Iwamoto and the rest of the team used trawling nets to survey bottom-dwelling life at depths ranging from 200-1200 meters. They focused their studies around underwater plateaus and mountains - areas that tend to be particularly rich in species, since they provide solid living platforms and create nutrient-carrying currents.

During the expedition, the team collected over 500 species of fishes, about 50 of which were grenadiers. Many of these grenadiers had never before been documented in the Tasman Sea, and two represented new species, which Iwamoto plans to describe over the course of the next year. These deep-sea species are well adapted for life at the bottom of the ocean, with huge eyes, highly refined sensory systems, and lung-like swim bladders that help them control their buoyancy.

Map by Colleen Sudekum
Team members sorting a catch of Richardson's boarfish.
During one trawling session, Iwamoto brought up this enormous grenadier (Coryphaenoides rudis), which was over four feet long. Photo: Ken Graham
One of the two new grenadiers that Iwamoto identified on the expedition, this species (Caelorhincus sp.) can be distinguished by the "saddle mark" spots on its back.
Photo: Tomio Iwamoto
The light organs on the underside of a firefly squid.