Subsistence fishing & South East Seasonal Monitoring Prep (Middle Camp & Cinq Cases)

In June we’ve been prepping for the upcoming seasonal monitoring which will take place throughout the dry season (South East). This is estimated to be around April – October but we’ve still been getting a bit of rain every so often so we haven’t been given the go ahead on starting the monitoring just yet.

As I mentioned in my last blog we are currently in a Pre RaCE (Rat & Cat) Eradication time frame. On the Atoll there are currently invasive rats brought to the islands by humans and also cats (Only found on Grand Terre) which have a huge impact on the natural biodiversity balance. There are plans to begin an eradication (but its is a huge undertaking to eradicate species, resource wise, time wise and financially). There are also risks to native wildlife that come with doing things such as baiting etc. so there are lots of things to consider. A RaCE team have been on Aldabra for the past few years conducting feasibility studies which they finished in March and have since left the Atoll whilst they write up their results. The next step is to secure funding for the eradication whilst the current research team (including me) conducts base line monitoring to allow us to have data pre and post eventual eradication.

The seasonal monitoring takes place twice a year (once in the dry season (South East) and once in the wet (North West) season) at five sites around the Atoll (Picard, Polymnie, DJL, Middle Camp & Cinq Cases):

-Bats (deploying acoustic recording song meters twice a year at three locations at 5 sites) - Terrestrial Arthropods (Pitfall traps x 6 at each site, Malaise Traps x 3 at each site & Beating x 3 at each site) - Land Crabs (26 transects total, each 100m split between 5 sites) - Small Reptiles (30 transects total, each 50m across 5 sites) - Landscape Evolution (Taking images of specific locations) - Soil Ecology (Tea Bag Index – litter and soil decomposition rates, tortoise faecal decomposition rates and soil depth/monitoring)

Other seasonal monitoring includes: Once a year (NW season) – Veg Composition & Biomass Once a year (SE Season) – Mangrove fauna

Monthly – Litterfall baskets (1st week of every month, Picard only), Rain Gauges Atoll Wide Other monitoring which is not seasonal but we are continuing include:

Twice a month: - Tropic Birds - Turtle tracks on West Grand Terre - Phenology

Three times a week: - Turtle tracks on Settlement Beach

Daily: - Rain Guage on Picard

As Needed: - Subsistence Fishing data recording - Biosecurity (Including Supply boat, tourism & ant surveillance). - Tortoise PIT Tagging at Cinq Cases

I might do a few blogs talking about each monitoring in more depth but that is a quick outline of all the monitoring I will be doing this year. As we weren’t able to begin the full SE monitoring yet I have been working with the rangers to continue cataloguing an inventory of all the research equipment we have in the office as well as continuing with the non-seasonal ongoing monitoring.

Between the 12th – 14th June the research team also went on a pre monitoring maintenance, mangrove plot selection and monitoring trial camp to Middle Camp & Cinq Cases. The camp was 2 nights and three days long. We departed Picard on the 12/06/2026 at 14:30 and returned to Picard on the 14/06/2026 at 19:00. Our first destination was MC where we stayed for the first evening and night. The channel to access the landing stage and hut for MC was like being in a Jurassic park movie. It was insanely gorgeous, with mangrove all down the sides and the mangrove trees full of red footed boobies and frigate birds all with their red balloons full.

The evening we arrived we carried out crab monitoring trials between 17:00-19:00 to allow me and Angela to practice our crab ID and practice following the protocols on the coastal crab transects.

That night we had rice, lentils & sweetcorn for dinner and played some cards before going to bed. The hut was a lot nicer than the hut at DJL and also a lot closer to the landing stage for the boat so we got off the boat and were pretty much right at the hut already. It was such a lovely setting. There was also an entire separate cubicle for our ‘shower’ which consisted of a bucket and a bowl to use to wash but there was also a separate ‘toilet’ which actually had a toilet seat on but is just a hole which goes straight down to the ocean.

I had made some peanut butter, oat and raisin cookies for us all to share which we ate for breakfast on the 13th June, before we all went out to do some maintenance on the existing transects around Middle Camp. This included adding flagging tape, labels and coloured paint dots to some of the transects as needed to make them easier to find/follow for standardised monitoring.

Later that morning we also went to the mangroves once the tide was low enough as we needed to select one more plot (9 had been selected during a previous trip). It took a while but we eventually found a suitable spot for the final plot, took a gps location, measured it out, marked the corners with red paint and added labels to the four corners. We also had to reselect a new area for plot 6 as it was too close to the edge (increased chance of habitat edge effect) and we managed to find a new plot in time to get back before the tides cut us off. This means when we go back for the monitoring all the plots are ready for mangrove fauna monitoring.

After lunch William, Rona and I went back out to continue maintenance on some of the crab transects whilst Angela, Clarisha and Norisha packed up camp and took a camp inventory (this is something we do at the end of every camp as non perishable food is left inside rat proof metal containers so that it isn’t needed to be carried every time). At just after 3pm we then left MC and headed towards Cinq Cases landing stage. Halfway there we had to stop as the water in the lagoon was too shallow to continue and it took about an hour until we could get going again. We eventually made it to the landing stage by 17:00 and started the walk to the hut. The walk to the CC hut is through mangrove and across very sharp champignon and took us around 1 hour and 15 minutes carrying all of our gear (very heavy) but this was us walking at quite a pace. Sometimes it can apparently take up to 3 hours to do the walk when the tide is high and there is lots of wading at the beginning. We eventually reached the hut at 18:15 and it might be my favourite of the huts I’ve seen so far. The table was in the middle of the hut with all of the beds around the outside. We had mushroom pasta for dinner and played some card games before dinner. Unfortunately in the evening I went to do a wild wee on the beach in the dark wearing my flipflops and I caught my toe on a rock causing it to bleed everywhere (I’m now on office work for 2 weeks to let it heal) but it was very inconvenient and annoying as there was still lots of walking to be done the next day.

In the morning on the 14th June we started with two hours of PIT tagging Aldabra Giant Tortoises. There are two zones where this currently takes place and we were focussing on the coastal zone area. The PIT tag is inserted into the left hind leg of the tortoise (between the knee and ankle) after checking with a scanner that it hasn’t already been tagged. We also take a GPS location of the original location of the tortoise when it was found and measure the Straight Carpace Length (SCL) of the 3rd Dorsal Scute using Callipers. Before inserting the tag an antiseptic solution is applied to the area and after applying the tag a powder is applied to assist with blood clotting. In total we managed to tag 27 tortoises between two groups in 2 hours.

At 9:30 William and I then headed off on a hike to collect the rain gauge measurement at CC Groves (taking a detour past Flamingo pond – which is a site known for spotting flamingos between June – August). William was hoping we might see some but hadn’t yet managed to see any, but we were very lucky that we managed to see 29 of them there! It was very cool, we hadn’t seen them at first and walked closer very confidently thinking there weren’t any and as William was getting his camera out I walked up to a gap in a bush and there was an entire group of them just there in front of me. Unfortunately they didn’t stick around very long and flew off but it was very cool to see them. In the end the total journey to the rain gauge and back (stopping at flamingo ponds both ways – they weren’t there on the way back) took us 2 and a half hours (my toe was hurting quite a lot).

Whilst we had been heading to CC Groves, the others had been doing maintenance on crab and reptile transects and after lunch William and I carried on some of the maintenance whilst Clarisha did the camp inventory. Rona, Norisha and Angela hiked from CC to Takamaka to collect the rain gauge measurement there. Clarisha, William and me then hiked back to the landing stage and had to wait quite a long time for tides to allow us to leave to meet the girls at Takamaka landing stage. Their walk took them around 3 hours 45 mins total but they had got a little lost of the way to the landing stage, luckily using the GPS they were able to get back on track following the markings. We eventually met them at 18:00 and were back at Picard by 19:00 (just in time for sunset and not having to spend a emergency night back at MC).

Overall it was a fun weekend, lots achieved and lots of walking!

Another thing that I have done this month (on the 10th June) is join a subsistence fishing trip as a recorder.

Aldabra’s marine resources have been strictly protected and conserved since the early 1980’s. In combination with the atoll’s isolation, Aldabra has escaped overfishing which occurs elsewhere in the neighbouring Seychelles islands. Fish is the main source of protein for staff working on Aldabra and subsistence fishing is allowed in the protected area to support staff permanently living on the atoll. The subsistence fishery has been carefully managed and monitored since the mid 1990’s ensuring the level and method of fishing is sustainable and does not impact on the marine protected area.

Bottom fishing is only permitted in the six designated food security zones distributed around the atoll as defined by the Aldabra management plan 2016-2026 It is mandatory that all fishing trips are monitored Monitor trends in the species composition, abundance and biomass of fish caught for each fishing trip in Aldabra waters. There are also restricted species which are not allowed to be caught for food and must be identified and returned to the sea immediately. When a fish is caught, my job as a recorder was to record the species, depth at which it was caught and fork length of the fish or record whenever a hook is lost to coral or shark. Two fishing methods are used here – Trolling or Bottom Fishing – this is also noted and the trip is divided into ‘sessions’ to allow us to calculate catch per unit effect = line mass (kg)/per line/per hour, fishing power, fishing time and fishing distribution. For bottom fishing a session starts when lines are in the water (no. of lines agreed beforehand) and the session stops if the number of lines increases, the motor of the boat is turned on, the zone changes or all the lines are out of the water. For trolling the session starts when lines are in the water (only 2 permitted- enter water at same time) and stops if the number of lines increases, a fish is caught (both lines come in) or all lines are out of the water.

For each fishing trip we record the trip details (Boat, personnel, weather conditions) the session details (fishing method, locations, start depth, end depth, no. of fishing lines, the session timer (start and end times & number of lines) and the fish details (GPS of catch location recorded using the CAT Phone to enter Data, depth caught, species and fork length measurement). Learning the fish ID will take me time, especially as I need to know the scientific name and the Creole names as they don’t really use the English common names here. Ike Jime Spikes or sharpened screwdrivers are used to quickly and humanely kill fish through brain ablation to preserve meat quality and to ensure they are killed in the most humane way possible. I have also been trained (through protocol, not any practical demonstration yet) on how to vent a swim bladder with a hypodermic needle to release a protected species which might have an inflated swim bladder preventing in from diving (this can happen when a fish is reeled in to the surface quickly). Luckily this did not happen whilst I was on the boat.