#02 2022

Off the deep end – the commercial experience

By Grant van der Heever and Arno Botha, SAEON Egagasini Node

On 26 January, two Egagasini Node team members, Grant van der Heever (instrument technician) and Arno Botha (NRF-SAEON/University of Cape Town PhD candidate) were thrown off the proverbial deep end when they were asked to board a commercial trawling vessel to collect data for NRF-SAEON’s bi-annual invertebrate monitoring survey off the west coast of South Africa. 

F/V Compass Challenger departing from Cape Town Harbour on a choppy day. (Photo: Grant van der Heever)

The R/V Africana, which turned 40 on 25 February, was unfortunately out of commission. This left the Department of Forestry, Fisheries and the Environment (DFFE) with no other choice but to use a commercial trawling vessel, Fishing Vessel (F/V) Compass Challenger, to fulfil their critical line function work of collecting data for estimating South Africa’s demersal hake biomass. The aim of these surveys is to provide high-quality fisheries data which are used to allocate the season’s total allowable catch (TAC) and are also necessary to maintain the fisheries MSC Certification.

The F/V Compass Challenger is a fishing vessel in every sense of the word. It is certainly not built for research, making seemingly simple tasks such as navigating to the trawl deck and carrying samples to the makeshift laboratory (i.e. fish processing factory) surprisingly difficult. Despite these challenges, the ship’s speed, manoeuvrability and hard-working crew made simple work of the first leg of this scientific expedition, with the demersal team managing to sample a total of 88 stations, with depths ranging between 36 and 638 m, in a period of only 14 days!

F/V Compass Challenger deck crew hard at work retrieving the trawl net following a 30-minute trawl. Inquisitive seals can be seen following the net with hopes of scoring an easy meal. (Photo: Arno Botha)

The samples collected on this survey will contribute directly to the Foundational Biodiversity Information Programme (FBIP) SeaMap Project, led by Dr Lara Atkinson at SAEON’s Egagasini Node, which aims to deliver South Africa’s first data-driven marine ecosystem map based on marine invertebrate species occurrence and DNA barcode reference library.

Personal experiences 

When asked about his experience, Grant stated: “It was definitely hard at first, knowing that I would have to spend two weeks on board a real working ship. We did not have the luxury of a well-equipped laboratory to work in or a lounge where we could wind down after a hard day’s work – we only had the trawl deck, the factory/laboratory and our tiny cabins. However, once we got into the swing of things, I think we started accepting our fate and made the most of the voyage. It was definitely an experience to write home about.”

This weird and wonderful Scaleless Dragonfish (Melanostomias niger) was trawled at a depth of 662 metres. These fish are adapted to the deep, dark seafloor, with their dark colour and light-emitting organs called photophores allowing them to navigate, communicate and hunt in total darkness. (Photo: Grant van der Heever)

A large Fierce king crab (Lithodes ferox) trawled at a depth of 548 metres. Close relatives of the hermit crab, these crabs have the unique ability of walking forwards instead of sideways like most other crab species. (Photo: Grant van der Heever)

Arno stated: “Despite some logistical challenges, the trip was enjoyable and extremely interesting as most of the stations were quite deep (>350 m), which meant plenty of weird and wonderful creatures. As a crustacean taxonomist, the highlight for me was catching some large lithodid crabs. Other highlights include all the different seabird species constantly following the ship, hoping for a snack from the net. Some of my favourites include the black-browed albatross (Thalassarche melanophris), Atlantic yellow-nosed albatross (Thalassarche chlororhynchos) and the brown skua (Stercorarius antarcticus).”

The beautiful black-browed albatross (Thalassarche melanophris). (Photo: Arno Botha)

The Atlantic yellow-nosed albatross (Thalassarche chlororhynchos). (Photo: Arno Botha)