Shark sightings start to increase

Cape Town’s Shark Spotters have seen 53 sharks so far this summer, a slightly lower number compared to the same stage of the season in previous years.

However, despite shark sightings falling by 35 percent at False Bay beaches between the summer of 2014 and the summer of 2015, Shark Spotters research manager Alison Kock is not concerned as sightings have started to pick up again in the past month.

“It was very slow in September and October, but were are starting to see more sharks. On Sunday (December 18), there were four different sightings at three different False Bay beaches,” Ms Kock said.

In May this year, the City revealed there had been 92 sightings in the summer of 2015 compared with 142 the previous summer.

“The sharks’ presence is all related to the environment. Water temperature is a driver of marine species, and, of course, there are factors such as availability of fish and prey. It’s not unusual for their numbers to fluctuate,” Ms Kock said.

Earlier this year, Sara Andreotti, of the evolutionary genomics group at Stellenbosch University’s department of botany and zoology, released the results of a study, which suggested that there are only between 353 and 522 individual great white sharks left in South African seas.

Her research, published in the journal, Marine Ecology Progress Series, was shared around the world.

However, Shark Spotters has questioned the findings, saying the methodology used might not have given an accurate reflection of the situation.

“One of the assumptions made in the recent study is that the Gansbaai aggregation site represents the entire South African white shark population.

“However, we are not convinced that this is true. Overwhelming scientific evidence shows that white sharks are separated by size and sex during part of their lives and that not all white sharks visit Gansbaai. It is therefore possible that the recent estimate underestimates the total population size,” the group said in a statement.

Ms Kock said Shark Spotters had also submitted a formal comment to the Marine Ecology Progress Series, which was awaiting publication.