Researchers have recorded a "strong presence" of four species of whales and another four species of dolphins in Maltese waters, including a whale that is “among the largest animals that ever roamed the planet.”

The viral social media videos showing dolphins swimming alongside boats this summer were most probably sightings of the Common dolphin, the Striped dolphin, the Bottlenose dolphine and Risso’s dolphin, all spieces which are still gracing the Maltese islands in hopeful numbers, according to the scientific survey conducted by the Environment Resources Authority.

On the other hand, even though whale sightings are less frequent by boaters, researchers could observe significant numbers of Fin whales, Cuvier’s beaked whales, Long-finned pilot whales and Sperm whales.

Sperm whales are among the largest creatures on the planet and the bigger ones are known to grow to lenghts of 52 feet and weigh around 40 tonnes.

Researchers sailed for 780 hours, covering 5796km, and observed pod movements and individual fish in each pod systematically and periodically.

ERA explained why people don’t see some of the species as often.

“Most of these species are sighted at lower instances, probably due to their presence at deeper depths and their migratory nature,” it said.

“The rare occurrence of some of these species is why it was fascinating for those who managed to sight at some whales off the Maltese coasts.”

The study found that some species are in Maltese waters all year round while others come and go in migratory patterns, but ERA said even though the populations of these are stable, “long-term monitoring is required.”

“Cetaceans (whales and dolphins) are not only beautiful marine animals which people like to encounter, but they are also an important part of our marine ecosystems,” said ERA official Miraine Rizzo.

“It is within this context that we understand the need to step up the protection of such animals in Maltese marine waters and ERA is committed to continue to improve knowledge on their needs and to address human impact on such species.”

All marine mammals, including whales and dolphins, have been strictly protected since 1992 and anything from disturbing them to hunting and killing them is illegal.

The results were published as part of Malta’s Assessment of Marine Waters – an extensive report on the conditions of marine life in the Maltese islands.