Tissue samples taken from a 4.26 metre squid that washed up on Scarborough Beach last week will be used to generate a DNA barcode, which may be helpful in the future to determine the current standing of the species globally, according to Iziko Museum.
The giant squid washed ashore on Tuesday August 16. In May, another one was found on Long Beach in Kommetjie.
Two Oceans Aquarium digital manager Devon Bowen identified the giant squid that washed ashore in Scarborough as Architeuthis dux, the longest squid species, which can reach about 13 metres.
He said that while most people thought these animals were very rare or mythical, they were surprisingly common all around the world and made up about 10% of all the stranded giant squids that had washed up on South African shores.
“The one found at Scarborough is actually a very small one, but it is very difficult to judge their age as squids of all sorts grow exceptionally quickly, and their growth rate is determined by water temperature and food abundance.”
He said giant squids lived in deep water on continental shelves up to about 1km and seemed to have a preference for cool, temperate waters like those around South Africa.
The shallow waters around the coast, like False Bay, were almost certainly not part of their natural range, and squids found in those areas were almost always near death, he said. Their maximum age was about 5 to 7 years, he added.
The reason for the standings was not always known, but it usually involved some sort of traumatic event, he said, adding that sperm whales hunted squids, and sometimes injured giant squids could escape in shallow waters and struggle to return to the depths.
“They are also prone to be dragged to the surface by upwelling currents (which are common on the South African coast), and these rapid changes in temperature and pressure could leave them weakened.”
However, the main thing to remember, he said, was that giant squids, like all squids, were only able to mate once and died soon afterwards, so it was also possible that a small specimen like this had been weakened after mating.
Dylan Clarke, from Iziko Museum, said a team from the Department of Forestry, Fisheries, and the Environment had collected various measurements and tissue samples on behalf of the museum.
Mr Clarke said the available information on giant squids was still poor and was based on dead or dying animals that had been washed ashore or captured in commercial trawl nets.
“There is just not enough data to be able to estimate things like population size, especially in southern African waters,” he said.
According to the current literature, he said, females could reach 12 to13 metres in length and males had been recorded at 10 metres, suggesting the one found at Scarborough was still growing.
