Moorings, Sound Traps, SPF and Beer... Sounds like another Field Trip to Mozambique!

{{First things first after any long journey - Oceans dips and a cold beer}}

Sometimes plans get made and field trips get organised so fast you don't have time to stop and think. That's how Rachel and I found ourselves a few weeks ago. Timings lined up at the last minute, decisions were made and the next moment hydrophones were packed away in hand luggage and I was off to meet Rachel in Durban to drive to southern Mozambique for a week to finish off work we started pre pandemic, exactly two years ago.

It's February. It's hot. We’re back and I’m prepared - I’ve packed plenty more SPFs, Aloe Vera, bug spray, cooling spray, skin care, meds, fans and beroccca. Rachel took one look at the size of my bag and laughed. It may be a week but I wasn't taking any chances second time round!

In 2020 we came in search of a few known humpback dolphins and Rachel joined me for her work on bottlenose dolphins. It was a very busy time and an exhaustingly amazing trip right at the start of my PhD journey. This time around, we're two years in and a bit more clued up.

{{Dolphins of Ponta - Photos taken from our 2020 field season by the wonderful Kira Louw}}

The aim of this trip is to get ‘naturalistic sounds’ i.e. sounds when there are no boats or swimmers in the water. The data we got last time from our in-water swims with Dolphin Encountours was fantastic, the first time we were able to match full spectrum broadband recordings with video footage of known individual dolphins, largely due to Angie Gullens intricate knowledge of the family structures from the past 10 years.

But do they make the same sounds when we aren’t around? Do they modify their communication when excited to see Angie and the boat? In Feb 2020, we collected several recordings from the boat with no swimmers present but the gold standard to answer these questions would be a moored hydrophone for completely passive recordings. So there we were, last night, 28 degree heat at 6pm cable tying concrete slabs together...

{{2M beer quickly becoming a key theme in this post}}

We'll deploy the SoundTrap for a week in the hopes of getting passive recordings of dolphins around the mooring. But as always, working in remote places, you have to do a bit of dynamic planning. Concrete blocks aren’t the best mooring weight (due to a low specific gravity underwater – they tend to float remarkably easily when wet….), so we upgraded our mooring to an L shaped mooring and will be checking on it regularly to make sure it doesn’t go walkabout. And as ever – impeccable timing – a cyclone is brewing off the coast of Madagascar which could hit us later this week with wind and big swells. So in addition to a wandering mooring, we will be monitoring the weather charts and ready to pull her out if need be before we loose a SoundTrap altogether.

{{Rachel on one of our afternoon land surveys spent monitoring dolphins around the mooring... the very conveniently placed Ponta Beach Bar providing shade and snacks}}

Aside from deploying the mooring, we will also be accompanying Angie on their daily in-water swims to record more from the semi resident group of dolphins here in the partial marine reserve (Rachel's hoping for more encounters with Rocha and Jaws in particular to strengthen her data set).

{{Another Kira Louw original, showing our in water recording set up from 2020. This year will be similar but with the new Hydromoth to replace the Sound Trap}}

It feels great to be back and, in the water, again with the dolphins. So far, we’ve had 3 trips and seen Rocha with her new calf and a group of Spinner dolphins (normally seen much further offshore). Aside from a few blue bottle stings and a little sunburn we’re off to a strong start. Angie, Mitch and Dallas making us feel as welcome as ever!

{{Happy salty faces after a successful mooring check plus added dolphin encounters around the Sound Trap}}