May 16, 2019
By Madeleine Brown (University of Melbourne), Sian Liddy (University of Sydney), and Jessica Radford (Deakin University)
Welcome aboard the 2019 CAPSTAN voyage! Dedicated to training the next generation of marine scientists, CAPSTAN offers students from across Australia the opportunity to learn blue water sampling techniques aboard RV Investigator. We’re the student team in charge of sea bird and marine mammal surveying from the observation deck, Monkey Island, as we complete a transit from Hobart to Fremantle across the Great Australian Bight. The three wise
monkeys students up in Monkey Island all have different educational backgrounds and interests, but share a common fascination with the animals we’ve come across at sea. Maddie and Jess have both recently completed their honours at the University of Melbourne and Deakin University respectively, and Sian has just begun her PhD at The University of Sydney. We were all drawn to Monkey Island to improve our bird observation and identifications skills as well as collaborating with the other CAPSTAN stations to combine bathymetric, oceanographic and planktonic data into cohesive research. Join us in Monkey Island!
Monkey Island is the highest point of the RV Investigator, bragging near 360-degree views of the wild Southern Ocean. We are led by Dr Ben Arthur, a bird nerd with unparalleled seabird and marine mammal ID skills, to help us identify unfamiliar species that we are encountering as we traverse the Great Australian Bight on our voyage from Hobart to Fremantle. Our entire journey is one long transect to record marine mammal and seabird biodiversity in this understudied area of the world. But it’s not just all monkeying around with charismatic megafauna – Southern Australia is home to ecologically and culturally important species that are facing global population declines, including Blue Whales and Wandering Albatross. Many of these species are migratory, so important information on their habitat use and aggregation areas can be challenging to acquire, but essential to the conservation of these species. Additionally, our transect is interrupted by an exciting detour to an array of deep-sea canyons. Why is this exciting? Well, emerging evidence has shown that large scale geological features have more influence over marine fauna assemblages than you might think. Submarine canyons can act as channels that cause upwelling with the right oceanographic currents. Upwelling of cool, nutrient-rich water into the photic zone can kick-start primary productivity, causing blooms of phytoplankton which facilitate a bottom-up trophic-cascade. In plain English – phytoplankton > krill > fish > seabirds and marine mammals! One of our aims is to document these aggregations in conjunction with oceanographic data collected by hydrochemists and oceanographers onboard.
There’s method to our madness in the bird and whale count. We use the mast on the bow of the ship to identify a 300 m wide area in which we record sightings. By keeping the area sampled controlled and consistent, we can get measures of abundance in different sampling locations. The species sighted are logged by a code based on their common names directly into the CSIRO database. This database is automatically populated with additional data to contextualise the sighting, including water depth, latitude and longitude, and direction of travel. We aim to examine the relationship between seabird biodiversity and water depth, and assess whether the diversity and abundance of seabirds decreases as we traverse further from the coast. Wind speed and measurements of fluorescence (a proxy for phytoplankton concentration) are also recorded to assist in identifying hotspots of high productivity for seabird and mammal feeding. We predict that these areas will be at shallower sections of the canyons due to upwelling. We also take high-resolution photos of species if possible, to capture distinguishing features that might help us with species identification after they’ve flown out of sight.
There has been a low number of seabirds and only one whale spotted so far, but we are keeping morale high ready to spot some fascinating wildlife as we sail towards West Australia’s coastal zone. Unfortunately, the oceanographic conditions at the canyons have not been favorable for upwelling during our survey period, but we’ll see if there may be any secret sub-surface interaction with fluorescence when we do our analysis! Additionally, seabirds are heavily reliant upon wind when foraging, so whilst our calm seas have been great for helping us find our sea legs, low winds may have influenced our sightings thus far. Despite it feeling as though we’re monkeying around in a marine desert sometimes, ecological data with low abundances is just as important as recording areas with high abundances! So at the end of the day, having an office that looks out over the Southern Ocean from sunrise to sunset and working on intriguing large-scale ecological questions is definitely a highlight of the voyage thus far.
Over and out,
The Sea Monkeys
Learn more about CAPSTAN from the CAPSTAN website at https://www.mq.edu.au/about/about-the-university/faculties-and-departments/faculty-of-science-and-engineering/departments-and-centres/department-of-earth-and-planetary-sciences/study-with-us/capstan and hear more from CAPSTAN students at voyage9181.wordpress.com! Also check out CAPSTAN director’s blog at aprilabbott.wordpress.com.