Maurits Van Zinq Bergmann - Acoustic Array Project October 2015

Sixty-six years ago George Orwell portrayed in his novel ‘1984’ a fictional entity called “Big Brother” who is claimed to rule a totalitarian state, creating a society that is under total surveillance by the authorities. Citizens are constantly reminded of this by the slogan “Big Brother is watching you”, an aphorism which is omnipresent on screens. In modern human society, Big Brother is inherent to abuse of civil rights, specifically in terms of mass surveillance. As bad as this may seem for human populations, however, mass surveillance by telemetry is arguably the most important and potent tool ecologists and conservationists have to protect natural populations and their habitats in increasingly human-dominated land- and seascapes.
In early 2014, the Bimini Biological Field Station (BBFS) established our equivalent of ‘Big Brother’ – an extensive acoustic underwater listening array, placed strategically in Bimini’s diverse marine habitats to monitor the movements of sharks and rays, tagged with 10-year transmitters. Each animal’s tag broadcasts its acoustic signal, every 90s or so and if within range of a receiver (i.e. ~500m), its ID, date and time stamp are recorded. Data builds, from minute to hour to day, month to year across different tidal phases, seasons etc. For the next three years I will use this data to identify drivers of movement, habitat preferences, spatial hotspots and mechanisms of habitat partitioning for Bimini’s local shark and ray fauna.








Only a few months ago I arrived at the station as a Principal Investigator to lead this project and have recently summarized our last 18 months of data. Some 48 sharks and rays from 7 species were detected by Bimini’s “Big Brother”. Interestingly, my first exploratory analysis has revealed that some species show a diverse habitat range throughout Bimini (e.g. an adult lemon shark detected on 34 receivers), whilst movements of others (e.g. southern stingray: 7 receivers) are more confined. It also appears that some habitats off southwest Bimini likely function as important corridors or highways for shark movement, detecting 20-30+ individuals. Further, I excitingly received information of our sharks ‘making moves’ outside of our array. Two male nurse sharks were detected in Andros and Grand Bahama, as well as migrating lemon sharks between Jupiter (Florida), Bimini and Florida Keys.
Surveillance arrays like the one deployed in Bimini provide valuable information regarding behavior, habitat and space use of sharks and rays on small geographic scales. While this information is crucial for effective conservation of local habitats, information about movements on scales of areas, countries or even continents is paramount to protect the populations that occupy them to conserve them for generations to come. Hence, small receiver arrays are gradually becoming larger and connected to other receiver arrays, creating large geographic scale networks. So is mass surveillance all that bad? I guess it’s a matter of perspective.




















Piece written for Save our Seas Foundation, and published on their website here too: http://saveourseas.com/update/mass-surveillance-not-all-that-bad/