Y12 Biology Trip: Gansbaai

On the 9th of May, the grade 12 biology class departed for a 3-day research trip in Gansbaai. 

Leaving at 6:45 that morning, we arrived at our accommodation around 9:00 to find a set-up including a shared kitchen and lounge, comfy rooms, and a pool table.

Following a briefing by Ralph, a marine biologist and knowledgeable guide, we went down the estuary to begin our research. 

Beforehand, we had investigated and prepared hypotheses, including how factors like whether or not the area is baited, temperature, salinity and oxygen concentration affect the density of mud prawns – key primary consumers in the estuary. After a prawn pumping demonstration and some practice, we split into groups to cover the first zone. We recorded data for 8 quadrats in each of the 3 zones.

We learnt methods for recording data, how to ID individuals in a population according to zone, the process of completing a practical experiment, and the realities of a career in marine science. 

The lunch break at the Great White House Restaurant was lovely. This particular restaurant had an entire whale skeleton secured on the roof, the life-size bones arching from the ceiling, along with various species of dolphin for comparison.

On the second day, we had our boat trip, led by our tour guide, Oliva, who simultaneously discussed marine wildlife while recording stats on all the species we saw with the rest of the crew for research purposes. 

Of the numerous creatures we saw was the entirety of the Marine Big 5: whales, sharks, seals, penguins, and dolphins. We were lucky enough to spot the elusive great white, a manta ray (the largest ray species) and a strange, pancake-shaped ‘sunfish’. 

Approaching the shark-cage-diving boats, we saw numerous bronze whaler sharks, which are commercially fished despite their low reproductive rate. The great white appearance was brief but impressive. The site has become rare lately due to the orca’s ‘Port’ and ‘Starboard’, responsible for 20 disembowelled sharks washed up on Gansbaai’s shores in March.

Sunfish, we learnt, don’t have teeth – evolving a beak to feed on jellyfish. They hunt in the cooler depths before coming up to float near the surface and sunbathe, hence the name, ‘sun fish’.

One island we visited was teeming with seals – a population of 60 000. Watching them in their natural habitat, loping on land and playing in the sea was wonderful.

On the final day, we visited the African Penguin and Seabird Sanctuary to watch the morning feeding and tour the facilities. 

The African Penguin’s ‘Critically Endangered status’ was also discussed, much of it boiling down to human interference. 

By using guano as a fertiliser, we stole the building material the birds use for egg shelters, leaving them bare and unprotected. Furthermore, overfishing has forced penguins to travel further to find food, increasing their risk of being attacked or strung up in nets. And while the penguins are contending with us, they also have to combat seagulls attacking their nests and seals searching for food. 

However, there are procedures in place to combat this: manufacture of artificial shelters, motions to convince the Department of Fisheries to impose more limits, and actions to balance the seagull population. 

There is 87% success in penguin rehabilitation and release. The remaining 13% are those we saw in the sanctuary – those that could no longer survive in the wild. 

While there, we were given a full tour and even had the chance to name one of the friendlier penguins, ‘Couscous’.

Finally, Ralph gave us an informative talk on his job, what it entails and the pathway into it. His study is on leopard cat sharks and pyjama sharks, focusing on how these similar but distinct species co-exist.

It was an incredible trip and well worth gaining practical knowledge and insight into a broad and unfamiliar field. Thank you to Dr Rat and Mr Jadezweni for making it possible!

– By Hannah