Reef fish management is tough: Can fisheries acoustics help? Kevin M. Boswell Marine Ecology & Acoustics Lab Primary Drivers Understand factors that act to structure ecosystems, primary focus on habitat function and use by nekton - Distributional dynamics - Habitat associations and linkages - Behavior and trophic interactions Requires continued development of novel approaches - Developing advanced approaches and platforms - Assimilating data at various resolutions and scales Difficulties lie in capacity for ‘observation’ High suspended load Diel variation- Day Diel variation- Day Night Pursue avenue other than transmitted light for ‘observing’ objects Active Acoustics • Acoustics are widely accepted tool for quantifying fish abundance and distribution across multiple environmental conditions • Benefits: reduced sampling effort, non-invasive, high resolution spatio- temporal data, reduced gear bias • Challenges: Require independent data to validate backscatter Barracuda vs. Menhaden Echosounder Imaging Sonar Plankton and 10 m small scatterers Fish 20 m Natural reef Acoustics to inform fishery independent surveys Aggregation studies: Goliath grouper- East Coast of FL. Permit- FL Keys Nassau grouper- Cayman Islands Pink snapper- Western Australia West Florida Shelf: J.C. Taylor, NOAA Courtesy of Chris Dowling/Dani Waltrick Artificial vs Natural reefs Natural vs. Artificial Reef Communities West Florida Shelf- Acoustic/Optical Fisheries Independent Survey Fishery-independent method to examine structure and biomass of reef communities at natural and artificial reef habitats Approach: Geographic and depth stratified sampling program, across 48 stations per year. Concurrent application of ROV, fisheries echosounders, and multibeam sonar - Rapid non-invasive/extractive methods - Accommodates study at multiple spatial scales - Quantitative metrics to examine reef-associated fauna West Florida Shelf- Acoustic/Optical Fisheries Independent Survey Ultimate aim- develop cost effective strategy to efficiently quantify reef fish resources and provide critical fishery independent data to fill data gaps within assessment process West Florida Shelf- Acoustic/Optical Fisheries Independent Survey Garner et al. 2019; White et al. In review Considerations for improving acoustic-based FI Surveys Survey Design Ground truthing Acoustic modeling Parallel 100m Flower 100m Survey design Parallel 100m Flower 100m Measure of means and variance will depend on: - Underlying structure of habitat - Spatial distribution of organisms - Transect design/patterns and autocorrelation White et al. In review Stereo Camera ROV Ground truthing BAD!!!! Acoustic data interpretation aided by validation of species, sizes, and orientation • ROVs/autonomous platforms • Baited/unbaited camera arrays • Stereo video systems J.C. Taylor, NOAA W.F. Patterson, UF • Lowcost options hand lowered through areas of high backscatter BETTER!!! Data needs: • Species ID, fish length estimates • Approximate altitude of fish off seafloor • Understanding effects of the acoustic dead zone Eurofishmagazine.com Lasers Gastauer et al. 2016 Target Strength Measurements: In situ/Ex situ estimates Acoustic properties of dominant fishes in GOM are largely unknown Currently require broad assumptions on taxa and TS-L relationships Opportunities for developing this baseline!! Considerations for improving FI Surveys Traditional Sampling points Benoit-Bird and Lawson 2016 Considerations for improving FI Surveys Traditional Sampling points Statistical approach to interpreting length and TS distributions Gastauer et al. 2017 Benoit-Bird and Lawson 2016 Probability Distribution Matching + offset = − ( + dist)/2 = Estimates of error can be derived around TS-L relationship Binder et al. In prep. Opportunities to characterize acoustic properties of GOM fish Imaged 149 individuals Balistidae (26) Haemulidae (78) Labridae (1) Lutjanidae (41) Serranidae (1) Sparidae (2) Boswell et al. Accepted Opportunities to characterize acoustic properties of GOM fish Imaged 149 individuals Balistidae (26) Haemulidae (78) Labridae (1) Lutjanidae (41) Serranidae (1) Sparidae (2) Boswell et al. Accepted Opportunities to characterize acoustic properties of GOM fish Boswell et al. Accepted Current and future efforts • Use orientation (angle) as a variable • Extraction of multiple features for classifiers • Examine classification success w.r.t. variation in orientation • Examining alternative analyses • Unsupervised clustering • Neural network classification Horst and Lane © When properties of dominant organisms are known… it can work. Kloser et al. 2002 90-170 kHz Broadband acoustics has potential 45-90 kHz to improve taxonomic resolution Broadband 35-45 kHz 120 kHz 70 kHz Narrowband 38 kHz Boswell et al. In prep Other types of sonars- Multibeam imaging sonar (Kongsberg M3) Shark depredation study on Permit a) b) c) d) e) f) Depredation mortality associated with catch-and-release angling on offshore Permit (Trachinotus falcatus) spawning aggregations in the Florida Keys, USA. Binder et al. In revision ARIS Imaging Sonar Pelagic interactions Marlin - Velocity (Δ distance) - Initiation distance - Turning angle/radius - Marlin size Sardines/Mackerel - Δ School Area - Expansion/Contraction rate Θt1 - Δ velocity New tools for enhanced insights Bait fish school Individuals Take home message Use of acoustics offers additional non-invasive data element - Develop long-term, repeatable and non-invasive data series - Complementary to other collection methodologies - Quantify biological patterns across broad (or fine) temporal and spatial scales - Behavior, habitat association, physical/ecological processes - Requires dedicated effort to provide ground truthing datasets - Special care should be taken when developing survey designs Where did all the snapper go? Part of stock ~limit level (B20) ~50-60% total allowable catch Pink snapper (not a snapper!) Assess acoustic methods -19 1- Target strength Latitude ( - Ex situ WA - Modelling ° ) 2- Biomass surveys -39 http://www.fish.gov.au/report/60-Snapper-2016 Scoulding et al. Acoustic optical survey in July 2020 Closed area WA Shark Bay Workshop on the Survey Design and Assessment Considerations for Aggregating Fish Species in Reef Environments Scoulding et al. Acknowledgements Collaborators: Sven Gastauer (SIO) Support: Jim Locascio (Mote) Will Patterson (UFL) Geir Pedersen (IMR) Ben Scoulding (CSIRO) Patrick Sullivan (Cornell) Chris Taylor (NCCOS) Graduate Students: Ben Binder Savannah Labua Ivan Rodriguez-Pinto Allison White MISC Passive Acoustics 0 103 -20 102 -40 J.Modigliani Frequency (Hz) 101 -60 Relative PSD (dB) • Passively listen to environment, 4 efficient method for long-term 10 0 -20 monitoring 103 -40 102 -60 Frequency (Hz) • Characterize dominant sound 101 Relative PSD (dB) sources in ecosystems, examine change over time 0 -20 103 • Presence and behavior of predators -40 102 -60 Frequency (Hz) and prey Relative PSD (dB) 101 Time Habitat Types MultibeamArtifical Reef- Oriskany Natural Reef- GC003 70kHz 70kHz Probability Distribution Matching + offset = − ( + dist)/2 = ( + dist)/2 = Matched Pairs Target Length Strength 120 -40.1 147 -39.1 162.5 -38.0 174 -37.0 194.3 -36.1 (Gasteur et al., 2017) Working Target Strength – Length Models TS = 10.00 * Log10(SL) – 50.03 Modal Intervals (Maclennan & Menz, 1996) TS = 20.00 * Log10(SL) – 72.17 Slope 20 (Simmonds and MacLennan, 2005) TS = 39.31 * Log10(SL) – 115.2 Least Squares Estimate (Cordue et al., 2001) TS = 23.90 * Log10(SL) – 90.74 Curve Fitting (Gasteur et al., 2017) Published TS-L relationships Other research pursuits Examining quantitative relationship between passive and active acoustic methodologies Night Study case: Goliath Grouper Night 100 95 90 85 80 SPL (dB) 75 Day 70 65 60 0 1 2 3 4 5 6 Days Boswell, Locascio, Binder Also important to characterize ecosystem changes September 12th September 26th November 4th After Before During Boswell, Locascio, Binder Low tide High tide Boswell et al. 2019 Functional groups respond to water level Prey Predator Fine-scale asynchrony between predators and prey Densities are linked to water level Patterns preserved irrespective of TOD Lowest densities associated with slack high-tide Greatest densities associated with low water levels BoswellBoswell et et al. al. 2019 2019 E&C D’Elia et al. In review.