Aquaculture Lab Tour

On Saturday, the 4th of February, the environmental portfolio organised a trip to the Aquaculture Research Aquarium in Sea Point.

Meeting at Queen’s Beach at 9:00, Dr Doyle started the trip with a talk about the geographical significance of the area. There, at Sea Point, is a contact point between an igneous rock (rock formed from magma) and sedimentary rock (rock formed from layers of sediments) at the ‘Sea Point Contact’ zone. We also discussed the formation of Lion’s head.

Following the geological talk, we were led to the lab and introduced to Dr Macey, who gave us the incredible tour.

The lab focuses on marine aquaculture research, with three main units: environmental, production and sustainability. The environmental unit is concerned with fieldwork, while the production unit studies indigenous and emerging species. Dr Macey himself studies pathogens.

To begin, we looked at the fish species they keep at the lab: the dusky kob, the spotted grunter and the flathead mullet. The dusky kob is currently at risk, its population decreasing significantly due to overfishing – and this is where aquaculture comes in. A key facet of aquaculture is its focus on sustainability, allowing for seafood consumption in a way that does not endanger certain species.

The tanks themselves connected to numerous pipes which ran throughout the building leading to biological filters that break down toxic excretory materials like ammonia.

While the tanks were big and the conditions carefully monitored to mimic sea life, it can still take a long time for animals to grow accustomed to captivity. For abalone, it can take up to 2 years – and this is just one of the challenges aquaculture farms face.

Larvae are especially vulnerable; in aquaculture, there is roughly a 10% survival rate for most species, which reduces drastically to 1% in the wild. Kept in top-quality water, larvae are fed live rotifers (a zooplankton), which are fed cultivations of microalgae, all of which the lab has to produce and monitor.

Another problem that aquaculture faces are algal blooms, which take over certain areas high in nutrients like nitrogen and kill pre-existing organisms. Despite this, scientists have found a way to establish a symbiotic relationship; by integrating uvula sea lettuce (which absorbs nitrogen) and abalone (which excretes nitrogen compounds) they create a very effective water filter.

Finally, we looked at the work that Dr Macey does with pathogens. He follows an extensive process of amplifying genes to identify the source of a disease by using PCR (polymerase chain reactions) or NGS (next-generation sequencing), the results from which are quantified with new technology. He can then study the DNA or even the prevalence of genes in certain environments.

Overall this was an amazing, and very informative trip. Thank you to the environmental portfolio and Dr Doyle for arranging it, and to Dr Macey for showing us around!

– By Hannah (edited by Danielle)

Photos by Kiara