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Third PhD-chapter on sea urchins and their macroalgal control abilities in Seychelles is out! Dream team with Victoria Beasley, Gilberte Gendron and @naj_graham. Thanks for the great editing @PoluninNick from @EnvConsJournal!
https://www.cambridge.org/core/journals/environmental-conservation/article/investigating-sea-urchin-densities-critical-to-macroalgal-control-on-degraded-coral-reefs/78414F16ACE03C7D518AFCA1F372D232
@LecReefs @HIFMB_OL
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https://www.cambridge.org/core/journals/environmental-conservation/article/investigating-sea-urchin-densities-critical-to-macroalgal-control-on-degraded-coral-reefs/78414F16ACE03C7D518AFCA1F372D232
@LecReefs @HIFMB_OL
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We took a detailed look at short-spined urchins (Echinothrix calamaris) and their ability to control macroalgae in the inner Seychelles. We did this in a two-part approach starting with modelling general patterns and followed it up with an experimental manipulation.
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Modelling across 21 inner Seychelles reefs suggests that E. calamaris are more present at patch reefs and more absent as macroalgal cover increases. This starts to highlight that the urchins' preferred habitat does not include macroalgae.
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So, could E. calamaris have caused this absence of macroalgae in their preferred habitat by grazing? We put different numbers (4 & 10) of urchins into pens to focus their grazing impact on a fenced 2.25 m²-area covered in mainly Sargassum macroalgae.
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Over 6 weeks, highest urchin density (4.44 urchins/m²) cleared moderate 13% macroalgae (our wild surveys found average 0.02 urchins/m²).
We conclude: At current densities, E. calamaris are unlikely to be important controlling grazers of macroalgae in the inner Seychelles.
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We conclude: At current densities, E. calamaris are unlikely to be important controlling grazers of macroalgae in the inner Seychelles.
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A million thanks goes out to my Seselwa friends from #SeychellesNationalParksAuthority (SNPA) and especially their rangers for their massive help with our study.
Mersi!
And in case you're wondering how to transport urchins safely - with massive chopsticks.
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Mersi!
And in case you're wondering how to transport urchins safely - with massive chopsticks.
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