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Endangered hammerhead sharks thrive at Point Waterfront canal
In the ocean, the survival rate of juvenile sharks is very low due to predation.
HAMMERHEAD sharks, which are listed as a threatened or protected species, have flourished in the Point Waterfront canal where uShaka Sea World has been assisting the Durban Point Waterfront Management Associaton (DPWMA) by supplying filtered water flow.
The South African Association for Marine Biological Research (SAAMBR), which includes uShaka Sea World, shared the news on their Facebook page.
uShaka Sea World’s aquarium curator Dr Justin Hart said the sharks have flourished in the area.
“In 2013, permission was granted to build a 25m2 enclosure for growing out various species from striped bonito to little hammerhead sharks. The sharks have actually thrived in this environment, and their presence offers a great education opportunity. They are released once our scientists feel they have they reached a size where they are less likely to be at risk from other predators, mainly other shark species, as well as when we feel they are reaching a maximum size for the enclosure. The sharks, which are monitored daily, are fed four times per week. In the ocean, the survival rate of juvenile sharks is very low due to predation, and this enclosure offers a safe space for the juvenile sharks to ‘outgrow’ the most sensitive and risky phase of their life cycle,” said Hart.
SAAMBR added that hammerheads are listed as threatened or protected species, and the hammerheads currently in the canal are nearing release time.
“We work closely with the Department of Forestry, Fisheries and Environment and inform them of planned releases,” said SAAMBR.
A flourishing ecosystem
SAAMBR listed several ways uShaka Marine World has booted a flourishing ecosystem at the canal: supplying filtered water at a rate of 250–300 m3/hour every hour; daily water-quality checks by their internal microbiology team, and managing the fish within the canal.
According to SAAMBR, there are more than 50 species of fish in the canal, with many species selected to manage marine algal growth, such as grazer fish and sediment-sifting fish, eg, Spotted Grunters and Sand Steenbras.
Not only do the fish add to a natural ecosystem, but they can also be viewed by the public in an ‘outside aquarium’ at no cost.
ALSO READ: Algae bloom in Point Waterfront Canal
The benefits of algae
According to SAAMBR, the water quality in the canal is very good, saying that due to its natural state there are algal blooms from time-to-time.
“These are not harmful to the inhabitants, it is a natural occurrence due to temperature increases and sunlight. The animals are not impacted by these blooms, if anything it contributes to higher oxygen levels during the day and often to higher zooplankton presence, a natural food to some of the fish, especially the smaller fish and larval fish,” said SAAMBR.
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