Graph showing length-weight data of Holothuria scabra collected by Steven in Natuvu Village, Savusavu, Fiji
(Updates from Steven on his sea cucumber project – sorry for the late upload)!
Alright. Another week in the field done and dusted.
Here I/we stand at t=2 done, which means I now have 3 data points for SOC and DOC, another set of sediment cores from each enclosure, and belt transects.
I had initially hoped to do at least 2 more transects, we ended up with 12 night time surveys + 2 day ones thanks to a very cooperative tide (the reef flat goes from ca. 2m depth at high tide to 10cm of water at low tide)
Good news: Found huge variation in species composition and size classes between day and night, more habitat associations, 150 more H. scabra measured and weighed.
Bad news: those 150 more H. scabra only improved the R-squared on my Length-Weight relationship by 0.003
Judging from the graph I will need more individuals >17cm, so no more belt transects (for Natuvu at least) we will be snorkeling in the 3 ‘blue holes’ and deeper areas near Natuvu island to find them. According to village records their last harvest was a year ago, they apparently only target larger individuals so we hope there are enough left!
To end on a good note, large individuals in our high-density enclosures were seen spawning on the afternoon high tide of the full moon! I’m going to try and catch this on camera next time just the fact that we can confirm a spawning event really adds to the knowledge bank we need to sustainably (ecologically and economically) manage H. scabra
For now I will prepare for t=3 and surveying those deeper sand patches.