CRUISES

Exploring the Depths: A Journey into Gascoyne Marine Park

Our team recently returned from a three-week expedition aboard the Adrianus, exploring the deepest reaches of the Gascoyne Marine Park off the mid-west coast of Australia. Led by Deputy Director Dr. Todd Bond, the team included Melanie Stott (Research Officer), Dylan White-Kiely (Research Assistant), and Jenny Wainwright (PhD Researcher). Together, we serviced a long-term deep-sea observatory located at a depth of 5000 meters and conducted 33 baited lander deployments, ranging from 1026 meters to 5074 meters.

Baited landers are essential tools for deep-sea research. They attract and video-record marine animals while resting on the seafloor overnight. The data collected helps us understand how animal abundance and diversity change with depth. The footage from this voyage revealed a remarkable array of organisms, even at depths of 5000 meters, including snailfish, cuskeels, deep-sea crabs, prawns, and even sharks and rays.

One of the highlights was filming a sleeper shark (Soniosus cf. antarcticus) off Ningaloo Reef at a depth of 2089 meters. This observation is notable because it was much further north and deeper than previously recorded. The temperature at this depth and latitude (2.4°C) is similar to much shallower depths further south, raising intriguing questions about the distribution of this species throughout the entire Indian Ocean, including deep tropical waters.

Another interesting sighting was the pointy-nosed blue chimaera (Hydrolagus cf. trolli), filmed at 2268 meters. This relative of sharks and rays, with its cartilaginous skeleton, is not uncommon in the deep sea. However, this particular species was unusually far from its typical range and likely forms a complex group of species in the Indian Ocean that aren't well-defined.

Our landers are also equipped with oceanographic sensors to measure current strength and direction, as well as water temperature and salinity. They include traps to collect specimens, which, like most deep-sea expeditions, yielded amphipods (small crustaceans) in abundance. These samples will help us understand how deep-sea basins like the Cuvier Abyssal Plain are connected to other deep-sea locations both regionally and globally.

We also collected some rare fish, including the tadpole whiptail (Squalogadus modificatus) from 1364 meters and a cuskeel (Bassozetus sp.) from 1945 meters. Though these species are found worldwide, they are often difficult to capture and are typically damaged when caught in trawl nets. Our samples were in excellent condition, providing rare and unique specimens. Tissue samples from these fish were snap-frozen in liquid nitrogen for genomic sequencing by scientists at the Minderoo OceanOmics Centre.

Back at The University of Western Australia, our team will carefully analyse the video footage to identify and count all recorded species. Oceanographic data will be analysed by Dr. Jess Kolbusz, while genetic analyses will be led by Dr. Paige Maroni and colleagues at the Minderoo OceanOmics Centre. 

We look forward to sharing the final report on our findings and the data collected in the first half of 2025.