Dr Eric Shaw’s take on attacks by killer whales documented recently in the Strait of Gibraltar

This summer a number of reports of killer whales (or Orcas) attacking leisure vessels in the Strait of Gibraltar and around the Portuguese coast began emerging. This species of dolphin is typical in this region during the summer months leading into September, however, reports of attacks are rare. Nonetheless, several reports of “deliberate attacks” have been described recently.

Scientists have proposed a number of causes for the interactions such as confusion, defensive behaviours or possibly a newly learned behaviour. These large animals are known to hunt tuna in these areas, and in recent times they have been noted as stealing tuna caught by Spanish or Portuguese fisherman. Obviously, this also results in an increase in interactions between these animals and humans. Dr Eric Shaw has worked with the dolphins in the Strait of Gibraltar for a number of years has proposed a potential explanation for these attacks:

“From what I’ve heard people describe or read in various articles, I think this is protective behaviour that is taking place. The first report was from the coast of Portugal and in the Bay of Biscay. These areas are well known for Tuna following the fish along the continental shelf at this time of year. In the marine world, we know food follows food, and fingerlings of smaller species are moving into deeper water where they become prey to larger species, onwards and upwards to the largest within the ocean.

What was interesting to read in the reports that it was taking place in the Straits also (lots of Fingerlings here too). Two places far apart at the same time, suggests they’re not the same family of Orcas. The reports stated that sailing vessels were being attacked. When a monkey bites you or a dog, we humans always say we have been attacked, but one question that needs to be answered was if the “attack” provoked in some way. There have been cases of sailing boats being sunk or damaged in the open sea by large whales these are in the singular, and all vessel owners state it was unprovoked!

What has not been considered is why these surface-dwelling Dolphins that “attack”, and only target sailing boats would be motivated to do this? We need to contemplate that Orcas have also bred at the same time as the small fish that they follow, there will be young that are being protected by the rest of the family from interlopers, or in our case rubberneckers. A sailing boat moving silently toward a pod of Orcas with young while they are following food would be seen as a threat. This strange animal with a strange tail that needs to be neutralised, finishes up with its tail/rudder damaged and so immobilised it is. So who was attacking who?
In my opinion, people tend to get far too close to wildlife on land and on the sea. Humans forget that they are perceived as a threat and will be “taken care of” by the defenders of the pods if they sail in a threatening manner. Notwithstanding all the above journalists do love a good story”.

It is likely that these Orcas were acting in a defensive manner, likely protecting younger or more vulnerable members of their pods. Interactions between marine life and humans are increasing at an unprecedented rate, the fact lies that humans are encroaching on the habitat of these animals. As such, these orcas feeling insecure because of boats is understandable. This highly intelligent species likely understand that these boats may cause harm and as such, will attack to protect themselves. That almost all reports mention attacks on the rudder of boats is interesting. This is similar to behaviour documented in the wild. As Eric states, by attacking the tail of an animal, Orcas understand that the individual is now immobile and thus no longer a threat. It is possible they are replicating this behaviour on vessels, targeting the same “anatomy” they know well; again highlighting their intelligence.

Recently, CEMMA (Coordination for the study of Marine Mammals) have published a study on a family of Orcas they believe to be responsible for a number of the attacks. Three juveniles known as White Gladis, Grey Gladis and Black Gladis, have been involved in around 61% of the reported incidents over the summer.
These three individuals exhibited a range of wounds caused by fishing lines or interactions with vessels (see CEMMA’s image of Black Gladis left) which are believed to have occurred in early summer before the attacks began. CEMMA scientists have stated that while the attacks may not be directly motivated by revenge, a higher instance of injuries associated with boats, may leave these individuals defensively cautious of vessels approaching them.

Whatever the cause of the interactions, the Orcas are no longer in the Strait but will return next summer. The best course of action would be for any vessel to give all marine mammals a wide berth going forward, at the end of the day we are in their habitat. A bit of respect towards these animals would go a long way.

Michael Hitchcock

Portuguese Man-o-War

The un-natural bloom of "Physala physalis" better known as the Portuguese Man-o-War that Gibraltar has been seeing this past week or so; can be put down to the last two months of South Westerly storms we have been having.

These winds have brought this species to our shoreline with waters from the Atlantic.

Physala physalis is a Siphonophore that uses a gas filled float to stay on the surface; the same float provides its movement through the surface waters in the direction of the prevailing winds. Other parts of the colony (it is a colony of animals all working to the same end) make up the digestive track and tentacles for capturing their prey.

The tentacles carry a powerful sting, stretching down and behind as the wind moves them forward, they should be given a very wide berth by swimmers and divers alike. They have been known to cause heart-attacks to some who have come into contact with the tentacles, which can be several metres long.  Where there is one there will be others, and it must be remembered when they are washed up on the shore line or beach the tentacles can still deliver their powerful sting.

Their main predators are the loggerhead turtle (Caretta carretta) and a small opithobranch Glaucus atlanticus  - a  sea snail minus shell, also called a nudibranch.

Notwithstanding all the above, it’s quite beautiful to look at. Do note however, that the bright colours are your first and only warning when encountered; be that shore line habitat, beach or in the sea. A wide berth is the watch word and don’t touch!

Photographs in this article were provided by R. Senior

New artificial reef created out of concrete stars in Gibraltar

Large concrete stars are being used in Queensway Quay to expand the breakwater line and create a more environmentally friendly marina. The stars, apply named “Gibraltar stars”, have been designed to establish an intricate underwater maze for a wide array of species to thrive in.

 

https://www.youtube.com/watch?v=5hXtKJv-g_4

 

The Gibraltar Star mould was designed so that it could be reused. To further reduce wastage, the excess concrete was also poured into disused oil drums to create a more diverse habitat. As the old adage goes; waste not, want not.

 This environmental project has been instigated by developer Paul Butler, owner of Marina Properties Limited, who believes that the long term benefits of conservation trump the short term profits.

 The artificial reef provides a diverse surface which is essential for many species to survive. The underwater crevices, which the stars create, enable young organisms in particular to take shelter from the dangers of marine life.

Concurrently, the Gibraltar Stars absorb the force of the waves, instead of diverting them, so that boats within the Marina will not be damaged during rough weather. In comparison, vertical sea walls only reflect the waves, causing nearby piers and properties to be eroded over time. Breaking down this action with the Star is a very forward thinking move.

 The Helping Hand Trust has praised the marina for their “ingenuity” in combining habitat creation with swell reduction. Developers and Environmentalists are often depicted as being at loggerheads with each other, but Gibraltar is seeing that stereotype challenged.

 The initial development of the Island project on the western side has already increased the Marina’s Biodiversity dramatically and marine researchers studying the site are astounded by the success.

Dr Eric Shaw, the founder of Europe’s first Artificial Reef said, “Most marinas have little other than mullet swimming in their water. But Queensway Quay Marina has brought the water quality up so high, that there are now crustaceans, like the swimming crab and squat lobster; soft corals and over 50 different species of fish, thriving within Queensway quay Marina.”

To the overall sadness for the causal onlooker, all this work takes place below the surface of the sea and hence, goes to the great part unseen. However it helps to know that environmental projects are taking place, making Queensway Quay Marina the most ecologically friendly marina in Gibraltar.

 

 

Monkey Movies!

Science and Communication Master’s student Jessica Olid has been working with the Helping Hand this summer to create a short series of wild life videos about our Barbary macaques. Collectively, her videos have reached over 26,000 people on Facebook both locally and internationally.

Jessica has been following the macaques for a number of weeks catching some of the funniest and greatest moments on camera. With the help of Dr Eric Shaw and research assistant Tessa Feeney, Jessica has been able to create three unique videos which teach us all about how the monkeys behave.

Dr Shaw said “The videos provide a fantastic opportunity for people of all ages to learn more about the Barbary macaques, in fact I would encourage anyone and everyone to check them out’’.

In her videos she demonstrates a side to the monkeys which is rarely portrayed. From newborn macaques, to how adults resolve arguments, her videos explore the macaques’ natural behaviours away from the hustle and bustle of tourists.

Jessica is hoping that these videos will help educate the public about the Barbary macaques and change public attitudes towards them. “As a local myself, I can see that all too often the macaques are portrayed in a negative light, instead we want to show people that the monkeys are intelligent peaceful creatures with distinct personalities’’ She said.

Filming has taken place within various locations of the Upper Rock Nature reserve, including areas of the rock that people seldom visit. Throughout her time with the Helping Hand she has encountered a number of challenges that arise when filming outdoors and working with a wild species; not the least of which involved the dangers of stepping in monkey poo!

Her videos have been very successful in helping us to educate the public and spread awareness of The Helping Hand Charity. You can watch all of the videos Jessica has created on our Facebook or on our YouTube page. Make sure you Like and follow these pages, as these videos are only just the beginning of our wild life nature series. 

Watch the first chapter here:

 

https://www.youtube.com/watch?v=9fejyHW6v9E 

Treasure Islands

We are excited to announce the release of Britain's Treasure Islands book and documentary series by Stewart McPherson and Redfern Natural History Productions.

The three-part documentaries series will start on BBC4 on April 12th at 9.00 pm. But before then, you can watch a free mini-documentary on Gibraltar here:

The project to document all of the wildlife, cultures and histories of the United Kingdom's Overseas Territories took four years and the result is incredible.

5,350 copies of the 704-page book have kindly been donated by Lord Michael Ashcroft to every secondary school in the UK and her Overseas Territories. Stewart McPherson was also extremely generous by giving copies of photos and film footage to locals as well as personally donating £21,300 which he divided between the territories to support conservation across the UKOTs.

Continue Reading