WALVIS BAY – The Ministry of Fisheries and Marine Resources says the thousands of horse mackerel trapped in a rocky reef at Mile 8 was not alarming but a common phenomenon known as a “walk out”.
The ministry of fisheries issued a statement in response to concerns raised by coastal residents after a video clip was circulated on social networks last week of horse mackerel that had been washed ashore and were being collected in large numbers at the shoreline at Mile 8.
A statement issued by the public relations officer of the ministry of fisheries, De Wet Shiluka, stated on Friday that this was not a strange occurrence for marine organisms, particularly fish, to be washed onto the beach or alive into pools on the shore.
“Fish can go wherever and whenever the conditions in the sea allow or force them to go,” the statement read.
The ministry, however, also pointed at environmental conditions, fish behaviour, and local changes in chemistry such as sulphur eruptions and oxygen deficiency as other possible causes of the phenomenon.
“However, after an investigation by our scientists no signs of a sulphur eruption at the time of the event was detected and so this was ruled out as a cause,” Shiluka stated.
He explained that phenomena of this nature are very common and many may occur unnoticed as there are very few inhabited areas/settlements along the coast. The phenomenon, which may occur unnoticed, happens when a shoal of fish swims too close to the shore during high tide.
“The predators approach from the deep and chase the fish into the shallows, which is the only possible escape route for the fish – the direction of the shore, causing them to end up where they were found after the tide.
Shiluka also explained that there is an estimated 36 billion individual horse mackerel surveyed in Namibian waters. The average annual horse mackerel total allowable catch is about 350,000 tonnes, which is about seven billion individual fish, hence the numbers given during the walk out were exaggerated.
“Filling up a single shopping basket, such as those in the video, would require about 150 individual fish. Given the numbers, it is obvious that the impact of the ‘walk out’ would be very negligible no matter from what angle, economist or ecologist, one may approach the issue,” he further stated.