Genetic analysis to evaluate diet of Red-footed Boobies (Sula sula) provisioning chicks at Ulupa`u Crater, O`ahu
Sarah E. Donahue*1, Josh Adams 2, Mark Renshaw 3, Brett Olds 3, K. David Hyrenbach 1; 1 Hawai‘i Pacific University, Waimanalo, HI sarah.donahue93@gmail.com; 2 U.S. Geological Survey, Santa Cruz, CA; 3 Oceanic Institute Genetics Lab, Waimanalo, HI
- Large scale temperature changes impact marine food web structure & predator distributions (Lehodey et al. 1997; Mantua et al. 1997; Wolter & Timlin 2011; IPCC 2014)
- Seabirds respond to short-term year-to-year (El Niño Southern Oscillation, ENSO) and longer-term decadal variability (Short: Surman & Nicholson 2009, Long: Velarde et al. 2015)
- RFBO yeild Key Indicator Species Characteristics:
- Non-migratory & colonial breeding
- Localized foraging (< 300 km) during breeding season (Adams et al. Unpublished; Weimerskirch et al. 2005; Young et al. 2010)
- Subsurface predator (SSP) associations (Harrison et al. 1983; Au & Pitman 1986; Hebshi et al. 2008)
- Respond to environmental change (Seki & Harrison 1989)
INTRODUCTION: Why Study Red-footed Booby (RFBO) Diet?
- Large scale temperature changes impact marine food web structure & predator distributions (Lehodey et al. 1997; Mantua et al. 1997; Wolter & Timlin 2011; IPCC 2014)
- Seabirds respond to short-term year-to-year (El Niño Southern Oscillation, ENSO) and longer-term decadal variability (Short: Surman & Nicholson 2009, Long: Velarde et al. 2015)
- RFBO yeild Key Indicator Species Characteristics:
- Non-migratory & colonial breeding
- Localized foraging (< 300 km) during breeding season (Adams et al. Unpublished; Weimerskirch et al. 2005; Young et al. 2010)
- Subsurface predator (SSP) associations (Harrison et al. 1983; Au & Pitman 1986; Hebshi et al. 2008)
- Respond to environmental change (Seki & Harrison 1989)
Examine RFBO diet using genetics
- Characterize RFBO diet
- Investigate two sources of variability
- 1) Interannual Variability (2014-Normal & 2015-El Niño): Does RFBO diet change during years of contrasting oceanographic conditions?
- 2) Sexual Dimorphism: Does RFBO diet differ by sex? Exhibit reverse sexual dimorphism
GOALS & HYPOTHESES
Examine RFBO diet using genetics
- Characterize RFBO diet
- Investigate two sources of variability
- 1) Interannual Variability (2014-Normal & 2015-El Niño): Does RFBO diet change during years of contrasting oceanographic conditions?
- 2) Sexual Dimorphism: Does RFBO diet differ by sex? Exhibit reverse sexual dimorphism
The Procedure
Freshness Scale Outcome For Fish (F) and Squid (S)
- 4 possible Freshness Scale Ranks (Complete (C) & Incomplete (I))
- More Squid yeilded better freshness compared to Fish
METHODS: Regurgitation Sorting
The Procedure
Freshness Scale Outcome For Fish (F) and Squid (S)
- 4 possible Freshness Scale Ranks (Complete (C) & Incomplete (I))
- More Squid yeilded better freshness compared to Fish
4 & 5) Genetic & Statistical Analyses
- 47% (492 of 1049) prey used - Freshness Ranks 1 & 2 used
- 82% (401 of 492) successfully identified (> 97% match) (Genbank)
- 98% (232 of 235) Squids - Sthenoteuthis oualaniensis, Purpleback flying squid
# Fish sp. drove diversity: 2014 Males & 2015 Females ate more fish than squid
RESULTS: Prey Identification
4 & 5) Genetic & Statistical Analyses
- 47% (492 of 1049) prey used - Freshness Ranks 1 & 2 used
- 82% (401 of 492) successfully identified (> 97% match) (Genbank)
- 98% (232 of 235) Squids - Sthenoteuthis oualaniensis, Purpleback flying squid
# Fish sp. drove diversity: 2014 Males & 2015 Females ate more fish than squid
RFBOs breeding on O`ahu have diet sexual differences in response to interannual ocean variability
Looking To The Future:
How Have These Squids Gone Unnoticed?
Purpleback flying squid – dominant prey for RFBO & other upper-trophic marine predators - Windward O`ahu : spawning grounds (Young & Hirota 1998)
- Suggest size shift of consumed squid – larger in 2015
- 2015 (7.2 +/- 1.1cm) > 2014 (6.3 +/- 1.7cm) (ANOVA, F_1,219 = 17.658, p < 0.0001)
CONCLUSION
RFBOs breeding on O`ahu have diet sexual differences in response to interannual ocean variability
Looking To The Future:
How Have These Squids Gone Unnoticed?
Purpleback flying squid – dominant prey for RFBO & other upper-trophic marine predators - Windward O`ahu : spawning grounds (Young & Hirota 1998)
- Suggest size shift of consumed squid – larger in 2015
- 2015 (7.2 +/- 1.1cm) > 2014 (6.3 +/- 1.7cm) (ANOVA, F_1,219 = 17.658, p < 0.0001)
MCBH: Todd Russell, Lance Bookless, Range Ordinance Escort; USGS: Josh Adams and lab (Max, Johnathan, Emily), BOEM: David Pereksta; Field Operatives: Lindsay Young, Eric VanderWerf, Robby Kohley, Randi Rhodes, Gwen Larrow, Dan Rapp, Sarah Youngren; Genetics Lab: Brett Olds, Mark Renshaw, Abby Golder; Oikonos – Ecosystem Knowledge: Michelle Hester; Committee: Josh Adams, Keith Korsmeyer; The Advisor: David Hyrenbach – Wouldn’t have become a great success without you!
*Also, thanks to Ty Tynan for help uploading the pictures to make this poster possible, thank you!*
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