Jack Ingelbrecht
Who I am
I grew up in the hills of Perth, Western Australia. When I was seven, every kid in our class had to do a video assignment for school. We each got to choose our own project and I decided to do mine on sharks and rays because it seemed like a good excuse to get my dad to take me to the big aquarium on the other side of the city. It worked! I still remember wandering through the premier reef tank exhibit, watching through the glass as the scuba divers hand-fed a shiver of grey nurse sharks. When we got home, I told my parents that I wanted to be a marine biologist. Looking back on it, I think all I really wanted was to get paid to swim around with fish. When I was 14, I obtained my open water diver’s certification and recreational skipper’s ticket. A year later I was a certified rescue diver with more than 50 logged dives. It was around this time that I looked up marine biology courses at Australian universities and quickly decided to study at James Cook University, Queensland, though not for any particularly important reason – it just happened to be the first university that came up in my Google search. After finishing my undergraduate degree, I returned to Perth and there completed a PhD at Murdoch University on threatened elasmobranchs of northern Australia. For many, a PhD marks the end of an incredible journey. For me, however, I hope it’s the start of something even better and I look forward to finding out what that is.
Where I work
While I am based in Perth for most of the year, field work has given me the opportunity to explore hundreds of kilometres of Western Australia’s vast coastline, from the World Heritage-listed Shark Bay to the Ashburton River in the arid Pilbara region. This project will take place primarily in the remote Kimberley and Pilbara areas of north-western Australia. These locations feature superlative natural phenomena and are globally important refuges for some of the world’s most threatened marine species, including the dwarf sawfish and green sawfish of the family Pristidae, which are the focus of this research. Coastal habitats in north-western Australia are largely intact and fishing pressure in the region is relatively low compared to most other areas throughout the Indo-West Pacific. These factors contribute to making this region an important hotspot for elasmobranchs. My previous sawfish research focused mostly on green sawfish in the Ashburton River and adjacent tidal creeks, an important nursery area for this species. The current project will have a broader scope; we will attempt to incorporate other populations of green sawfish in the Pilbara region and northern Australia, as well as populations of dwarf sawfish, the most understudied of the pristids. Much of the work on dwarf sawfish will take place in the Kimberley region, primarily in the estuarine waters of the Fitzroy River and adjacent King Sound, which are believed to be important pupping grounds for this species.
What I do
This project implements the latest genomic techniques to gain crucial genealogical and population genetic insight into some of the world’s most important populations of dwarf sawfish and green sawfish. For the dwarf sawfish, we employ one of the most important but often overlooked applications of genetic data: their use in identifying and distinguishing between close relatives and unrelated individuals within and among populations (i.e., kinship). This information can provide incredible insight into the individuals that make up a population. We examine the spread of kin throughout the Kimberley region to infer population connectivity and look at patterns of movement and reproductive behaviour. It is hypothesised that female dwarf sawfish are philopatric, so one of our objectives is to investigate the occurrence of maternal half siblings in sampled populations. This will help us to determine whether mature females are returning to the same site for reproduction.
In the case of the green sawfish, we have already conducted a detailed kinship investigation within nursery populations of this species across the study area. Now we are investigating genetic diversity and the extent of inbreeding within sampled assemblages, as this information is limited for populations of this species in the southern Pilbara region. We are also investigating the extent of population differentiation (i.e., population structuring) for the green sawfish to determine whether sampled assemblages constitute genetically distinct populations. It is my hope that this project will contribute to more effective conservation strategies for these sawfish species, both within northern Australia and globally.