Until a worldwide ban took effect in 1986, whaling and the production whale products, were leading to a decline in whale populations. Despite a greater global awareness about the importance of protecting our oceans, conflicts still exist between conservation efforts and industry.
This week’s guest, Dawn Barlow, studies the anthropogenic effects on blue whales (Balaenoptera musculus) – the largest known animal to have ever existed! Dawn is a first year PhD student in the Department of Fisheries and Wildlife’s Geospatial Ecology of Marine Megafauna (GEMM) Labwith Dr. Leigh Torres – the same lab where she completed her Master’s degree in 2018.
Discovery of new whale population… and problem
Through her Master’s work, Dawn and her colleagues were able to document a genetically distinct population of about 700 blue whalesin the South Taranaki Bight (STB) – a region located between the north and south islands of New Zealand. The STB is not only an important region for the blue whales; however, it is also heavily used by industry, with active oil and gas extraction, seismic surveying, shipping traffic, and proposed seafloor mining. The need for a marine sanctuary in this area is eminent for the longevity of this whale population, but a compromise must be reached with the government and stakeholders. Furthermore, defining a sanctuary area in a dynamic system is not as simple as drawing a line in the sand.
Data collection Down Under
For her PhD research, Dawn will be continuing work with this same population of whales to get a better understanding of the ecological factors that influence where the blue whales are distributed. So far, three data collection trips have been conducted to gather some of this information. These ship-based trips have collected huge amounts of data using a myriad of equipment and techniques.
Echosounder data is collected using a transducer, which hangs off the boat and sends two pings per second producing measurements from the bounce back that can be used to map out krill aggregations – the blue whale’s primary food source. Conductivity, Temperature, Depth (CTD) casts are used to collect temperature and salinity pressure measurements to determine depth. Wind measurements are also recorded, as this generates upwelling. Photography and videography from the ship deck and via drones are used for identification of individuals whales with their skin providing the equivalent uniqueness as a human fingerprint. Satellite imaging is also used to record sea temperatures and chlorophyll levels. Lastly – and my personal favorite – darts shot from a smaller inflatable boat at close-range are used to collect skin and blubber samples for downstream genetic, stable isotope, and hormone analysis. Opportunistic sampling of fecal matter (i.e. if a whale poops) can also be used for genetic and hormone analysis.
Dawn participated in the 2017 field season and also went in July 2018 to disseminate findings to stakeholders. Now she is tasked with sifting through the data to correlate the oceanography with acoustic data, satellite imagery and presence of krill. Preliminary results suggest that the blue whales seem to appear where krill aggregate. Through habitat modeling on an ecosystem scale, Dawn hopes to be able to predict on a seasonal scale where the krill – and therefore, blue whales – will be, allowing for informed, science-based conservation and management decisions to be made.
Finding a passion for conservation biology