Reports of UFO sightings are quite common during the summer in Malta - not of the flying kind, but unidentified 'fishy' objects.

Without fail, rumours spread about "big fish" having been sighted, and many people automatically assume they are sharks.

Following two reports last week of a big fish in Grand Harbour, the Armed Forces went to investigate - and all they found was a fishing net.

People have been known to play pranks to keep swimmers away from a bay and have it all to themselves.

But could there be some truth in the big fish reports?

Stanley Farrugia Randon, a doctor and fishing enthusiast, said he would not be surprised at all if big fish came close to the shore chasing prey.

"Of course, reports of big fish being seen close to the coast are more frequent in summer than any other time of the year because more people spend more time at the seaside, and the warmer the weather, the closer the fish come in.

"But they could be tuna and dogfish. Dogfish belong to the shark family and they surface to catch their meals. Sharks do not normally attack people and certain species eat through filter feeding."

Dr Farrugia Randon authored The Fishing Industry in Malta: past, present and future, as well as Fishes of Maltese Waters with Rio Sammut and Il-Hut in the Kullana Kulturali series by Publikazzjonijiet Indipendenza.

"Dogfish are very similar to sharks and often come to feed close to shore. I have seen dogfish come close to the quay at Bugibba to feed and most people would mistake them for baby sharks.

"One has to bear in mind that certain people exaggerate and add colour to their stories, which then get even bigger and more fanciful as they do the rounds," Dr Farrugia Randon said.

Mark Fenech, 25, said he recalled reading that when the film Jaws was first released, many people around the world gave up swimming temporarily.

Jaws was an exaggerated version of what sharks can do to humans. Giving the Great White Shark in the film human-like reactions imprinted in viewers' minds scenes of horror which they tend to recall when in the water.

"A lot of people tend to identify stories of big fish with the Hollywood films and documentaries they see about sharks. So swimmers panic if their legs or arms brush against something.

"I love swimming but although the sea is extremely inviting around Delimara and Filfla, I wouldn't swim there for all the money in the world," Mr Fenech said.

Susanna Menta said she had recently gone on holiday with friends on a 34-foot boat to Tunisia and the Greek islands and although they had seen shoals of dolphins, turtles and baby tuna surfacing in schools, they had not seen any sharks.

There are several stories from the past about big fish.

In their book Fishes of Maltese Waters, Dr Farrugia Randon and Rio Sammut wrote that Giov. Francesco Abela in his work Della Descrittione di Malta, published in 1647, narrates that a huge monster with double rows of teeth was washed ashore following a storm.

In April, 1890, two Maltese fishermen were killed by a large fish that Dr Nicola Giovanni Gulia MD claimed was a Great White Shark.

A couple of days after this incident, a big fish weighing 648 kg was caught at Mellieha. An ex voto painting at the Zabbar Sanctuary Museum is the only vivid memorial of this incident.

Giuseppe Despott, superintendent of fisheries, wrote that on June 16, 1928 a basking shark got entangled in some nets opposite St Julian's tower... "Our specimen was 25 feet 2 inches long from the point of the snout to the end of the upper lobe of the tail."

In July, 1956, Jack Smedley, an English teacher, was attacked and carried away by a shark in St Thomas Bay.

On April 17, 1987, a fisherman from Zurrieq hooked a 7.2-metre Great White Shark while fishing near Filfla, the largest ever caught in Malta, and perhaps anywhere else...

Vince Milton, managing director of Divewise Services Ltd who has been diving in Malta for the past 32 years, said that reports of big fish had become routine.

"In spite of regular reports, no harm has come from these fish. Five years ago, somebody reported sighting a big fish and then the next report said the big fish was pregnant and with every day that passed the story got bigger and bigger...

"It's wrong to say that this does not happen, but I reserve judgment about all these fish sightings. However, if one were to take these sightings seriously, then one should seriously consider the effect of tuna pens in attracting sharks.

"The migratory habits of tuna coincide with the migratory habits of sharks. When the tuna penning industry gets up and running, we can expect to see more sharks coming in closer to shore," Mr Milton said.

Michael Testa, a seasoned amateur fisherman, said that people tended to exaggerate.

"The other day a friend of mine who was fishing at night heard what he described as a big splash and his theory was that a whale had surfaced close to his boat.

"Fins cutting through the calm waters and big splashes of schools of fish surfacing at one go tend to trigger the imagination of witnesses who immediately recall the images they have recorded in their subconscious," Mr Testa said.

Ivan Portanier, producer and presenter of the Radju Malta programme on the fishing industry Bejn Sema u Ilma, said dolphins regularly entered Grand Harbour frolicking in the water, chasing prey or following boats.

"Is it possible that such sightings involved dolphins or a sun fish (mola)? Some time back, a practical joker nailed a swordfish fin onto a piece of wood and anchored it near il-Merkanti reef near the Dragonara.

"These days sharks are getting extremely scarce. About 30 years ago, Hammerhead Sharks (kurazza), Blue Shark (huta kahla), Porbeagle Shark (pixxiplamtu) and the Seven Gilled Shark (murruna) were caught regularly on long lines used for fishing for swordfish and tuna.

"But now it's been years since a hammerhead was caught. Incidentally, one was caught last week from about 50 miles offshore."

Shark meat tastes good. It is not sold as shark meat because the word 'shark' like 'kelb il-bahar' is a generic name. The different types are sold by their particular name such as kurazza, huta kahla and so on, Mr Portanier said.