HWDW

A spate of whale and dolphin deaths along Scotland’s west coast is being linked to the hunt for a Russian submarine.” 13 Sep 2018

In August and September 2018, 82 whales washed up on the west coast of Scotland including Cuvier’s beaked whales. These are some of the deepest-diving mammals on the planet reaching more than a mile deep and rely on echolocation or biological sonar to navigate the pitch-black depths of the Atlantic sea. As a result, they are highly susceptible to loud underwater sounds such as sonar, which some marine biologists worry could be causing them to surface too quickly in distress. It is suspected this could lead to them suffering from decompression sickness – a condition that can also prove fatal to human divers.

Other potential factors under consideration to explain the remarkable amount of fatalities include pollution and disease. The average stranding numbers for these animals is around two and a half per year. So this number in just over a month is unprecedented.

May 2018

Joint Warrior, a UK led NATO military exercise, came to an end off the west coast of Scotland last week. This biannual exercise normally takes place for two weeks each spring and autumn, and is the largest multi-ship, multi-threat exercise conducted by the Royal Navy in UK waters.

Military sonar used during these operations produces an intense loud noise that can disturb and harm cetaceans. At HWDT, we believe that it is important to monitor cetacean presence and behaviour during these exercise We have been running monitoring surveys to coincide with the Joint Warrior exercises since 2009, using acoustic and visual data to help understand the impact that these activities may have on cetaceans across the Hebrides.

Our spring Joint Warrior survey took place from April 24th to May 2nd, during which Silurian covered 318 nm recording over 41 hours of acoustic data.

Thirty-five recordings of military sonar were made, 13 of which were categorised to our highest rating meaning the sound was loud enough to mask all other oceanic noise. One of our citizen scientists described it as “the worst sound I have ever heard”.

During the nine day survey, there were 43 marine mammal sightings of 50 individuals from five different species, including grey and common seals, harbour porpoise, Risso’s dolphins and on the last day an amazing minke whale!

Feb 2019

The HWDT has called for greater protection for sea life off Scotland’s west coast after extensive and “pioneering” research that identified the area as a hot spot for whales, dolphins and porpoises.

The “extraordinary biodiversity” was revealed by the first Hebridean Marine Mammal Atlas that was compiled after 15 years of work by the Hebridean Whale and Dolphin Trust (HWDT).

The waters of the Hebrides are teaming with 30,000 sightings of 23 different species or a quarter of the world’s known species – including minke whales and basking sharks.

The survey area covered an enormous swathe from beyond Cape Wrath south to Kintyre. Among the trust’s discoveries are that the Hebrides provide a vital feeding ground for minke whales and basking sharks and its researchers were the first to suggest that bottlenose dolphins live all year round off the west coast.

The region is one of the most important areas for harbour porpoise in Europe with more than 5,000 sightings over the years – by far the most for researchers on any of the surveys.

Despite the high porpoise numbers being reason for cheer for conservationists, other species of marine life are not so fortunate such as the UK’s only resident population of killer whales or orca.

The group of eight individual orcas is called the West Coast Community but it is feared the pod will be extinct within a generation because no calves have ever been seen.

Hump Back whales are also extremely rare – but have made seven appearances since 2004 mostly around Northern Ireland and as far west as St Kilda, taking in the waters in and around the Outer and Inner Hebrides.

Threats to Cetaceans

While the persecution of some whale species, such as humpbacks and blue whales, has reduced as whaling has declined, others are still under threat from a range of factors. Dead whales washed up in Asia starved and dehydrated because their stomachs are full of plastic. In Europe, killer whales are carrying dangerously high levels of banned PCB chemicals in their blubber, most likely bio-accumulated, as killer whales are apex predators in a long food chain. Pollutants are suspected for causing the death of five sperm whales that became stranded on the East Coast of UK

Exxpedition, Round Britain 2017, the last sailing expedition I took part in, set out to investigate the levels of micro plastics in British coastal waters: micro plastics attract persistent organic pollutants such as PCB’s, effectively concentrating the chemicals. The micro plastics then became part of the micro organism ‘soup’ which sustains the marine food chain (and ultimately human beings too).

This expedition, Joint Warrior, will be investigating a very different type of pollution, but potentially equally damaging to cetaceans. Sound pollution.

The ocean is a world of sound, not sight.  Marine mammal species perceive the sounds of sonar as a threat and react accordingly. Noise emanating from passing ships may disturb animals such as killer whales and dolphins far more than previously thought, with new research showing that the animals’ communication and ability to find prey could be hampered by the underwater din.

UK’s last resident killer whales 'doomed to extinction'?

There are several knock-on consequences of a noisy marine environment. Whales may have to group together more closely in order to hear each other. Consequently they occupy less marine ‘space’ and so have access to less prey. And should they fail to find prey as effectively, they will need to use up their stores of excess blubber which often contains manmade pollutants such as PCB’s. These are toxic to whales if released fully into their systems.

The mass stranding of 39 long-finned pilot whales in 2011 in Scotland and a group of common dolphins stranding on the shores of Cornwall in 2008. In both of these cases a government report later revealed that the likely reason for the mass stranding was naval underwater detonations.

More work needs to be done to identify how badly the noise is affecting whales and also to quieten the ships that pass near the cetaceans in order that more work will be done to restrict noise pollution in the sea. For example decreasing  speed by six knots could decrease noise intensity by half.

In the UK there are some regulations and limitations in place already. These include regularly assessing possible cetacean habitats, ways of minimising impact on marine wildlife in Royal Navy’s basic training and increasing the intensity of sonar gradually so that the animals can begin to move away from the unpleasant sound. Furthermore, assessments of the impacts of different sources of noise to marine life and the identification of important cetacean habitats, breeding grounds and migration routes are done regularly.

The Royal Navy is now required to turn off sonar systems if animals are in the area and are banned from using pulses higher than 180 decibels within 22.5 kilometres (14 miles) from coasts, especially coastlines belonging to 'biologically important' areas. However, while no one is saying that the Navy is disobeying their current policy, a new ruling states that the regulations currently in place are not doing enough to protect the sea’s creatures and that new rules and guidelines need to be put in place. 

Exhibition I have curated, including microscopic images of micro plastics
collected from Leeds Liverpool canal, plus embroidered waste plastic textiles.

Blue Planet Live

Did you see the grey whale deliberately make contact with Chris Packham? I cried. These extraordinary beings are suffering- again- first they were hunted almost to extinction before we appreciated how much they meant to us as living beings rather than oil. Now they are suffering both due to our toxic and wasteful lifestyles via chemical and plastic pollution, warming seas and decreasing food sources but also their very ability to communicate with each other is being disrupted our noise pollution. Sonar may also be affecting their health at other levels- imagine being bombarded with high decibel rock music.

I was able to be part of a round UK sailing expedition to monitor micro plastic levels in UK coastal waters, directly after Blue Planet 2 and David Attenborough’s powerful plea on behalf of our oceans, our home, to reduce plastic waste. Now I feel so honoured to be able to sail with the Hebridean Whale and Dolphin Watch next week, directly following on from Blue Planet Live.

What is Sonar

What is sonar?
Sonar is an acronym for Sound Navigation and Ranging. There are two broad types of sonar in use:
• Passive Sonar. Passive sonar is a listening device that can determine the presence, characteristics and direction of marine noise sources. These sources may include biological noise (animal communication) and human sounds (eg ship or submarine noise). Passive sonar equipment is essentially an acoustic receiver which emits no sound and therefore has no potential to disturb marine life.
• Active sonar. Active sonar is a technique that uses sound to determine relative positions of submerged objects (including submarines, fish, mines and wrecks of ships and aircraft) and the sea floor, by emitting a sound signal and listening for the echoes from the objects. Many different types of active sonar are used throughout the world's oceans by private, commercial and military vessels. These systems mirror the purpose of sonars used by some marine animals. Active sonar devices locate objects by the reflection of sound-waves and remain an important means of underwater detection and navigation.
Potential impacts on the marine environment
The potential for sonar to impact on the marine environment is a function of the output power, the transmission frequency, and the sound transmission characteristics of the marine environment. The potential for impact on an individual species depends on its hearing response characteristics and behavioural sensitivity, and its distance from the sound source.
Output power
The strength of the active sonar transmission is an important factor in considering potential impact on marine species. The output power of active sonar is dependent on the designed purpose of the system. If the system is required to detect objects or the sea floor at great distances then high power transmissions will be required. This is because only a small amount of the output power may be expected to be reflected back to the detector from an object distant from the source. High power sonars include military antisubmarine sonars, commercial sidescan sonars, deep water echo sounders and fish finders. Lower output powers are used for sonars designed to detect objects in shallow water or close to the source.
Output frequency
Active sonars use a range of frequencies depending upon the role of the equipment. Lower frequencies (below 20 kHz) have potentially greater ranges in seawater due to lower rates of sound attenuation with distance. Detection of distant objects therefore relies on the use of lower frequencies, the lower the better, however, lower frequencies are not suitable for detection of small objects.
High to very high frequencies (above 100 kHz) provide excellent resolution of objects such as fish, small objects, and the sea floor but suffer from severe attenuation with distance from the source. These systems are only practical in shallow water or for short range detection of objects near the source.
Output power levels versus received levels
The sound source level will appear to an observer to reduce with increasing distance from the source. This is because the sound is reduced in intensity as it travels as a result of loss of energy from the sound wave and spreading the energy more thinly as the wave spreads out. The perceived output at distance is called the Received Level. Determination of potential impact on a species must use the received level, not the source level which is an abstract measure of the source characteristics (received levels are always lower than source levels). It should also be noted that sound levels quoted for various sources in air bear no direct relation to in-water sound sources. For example, comparing some sonar output power levels with jet aircraft noise is inaccurate and misleading.
Receptor species auditory characteristics
The potential for active sonar to impact on a species is dependent on the ability of the species to hear the sound. Species hear sounds over different frequencies ranges, and the efficiency of sound detection varies markedly with frequency. Additionally, species behavioural responses to a detected sound may vary according to the sensitivity of the species to disturbance and what activities the animals are engaged in at the time.
Determination of potential impact on a species must therefore include estimation of the ability of the species to detect the sound, and the likelihood of disturbance to critical activities such as feeding or parental protection of juveniles.
Types of military sonar
The main types of active sonar used by military forces are:
• Low-frequency (LF). Low frequency sonars have been defined as those that emit sound below 1000 Hz. These sonars are designed to provide theatre level protection, such as for an Aircraft Carrier Task Group out to many miles (up to 200 miles) from the ships. This is possible because of the extended propagation possible at low frequencies. Outputs are similar to medium frequency sonars (described below) but the sound travels further because of the significantly enhanced seawater propagation. The low frequencies employed require large transmission arrays and are fitted to large ships. Two examples are the US Surveillance Towed Array Sensor System Low Frequency Active sonar (SURTASS LFA) and the Type 2087 Sonar being deployed by the UK Navy. Only a small number of these LFA sonars exist. They are not used by the Royal Australian Navy, and have not been operated in Australian waters by other Navies.
• Medium frequency (MF). Medium frequency active sonars emit sounds at frequencies between (1000 and 10,000 Hz). These sonars represent a sliding scale of compromise between possible detection range and size of the transmission array. At the lower end of the frequency range (1000- 3000 Hz) the systems are capable of extended detection ranges using high output power, but the size of the transducer limits applications to large warships. These systems are designed to provide area protection for a small Task Group out to a few tens of miles. An example is the US Navy SQS-53 series of sonars fitted to larger US warships. The Royal Australian Navy does not operate these systems. At the upper end of this frequency range (3,000 – 10,000 Hz), sonar arrays are smaller and output powers are less, but the systems can be fitted to smaller vessels. These systems are designed for ship self protection out to a few miles. Examples include the SQS-56 and Spherion systems fitted to Australian warships.
• High frequency (HF). High frequency active sonars operate between approximately 30,000 and 500,000 Hz (30 kHz and 500 kHz). These systems allow increasingly greater resolution as the frequency increases but at the expense of range. The highest frequencies are only effective over short distances because of the rapid attenuation of high frequency sounds in seawater. These systems are used by the Royal Australian Navy for minehunting and sea floor searches, and for hydrographic survey. These sonars are similar to commercial fish finders and sidescan sonars designed to search for fish, map the sea floor and search for sunken objects.
Typically high power military active sonars are operated infrequently during voyages and the sounds are not emitted continuously but as short bursts ('pings') during operation.
Commercial and civilian active sonars
Commercial and civilian sonars are generally designed to detect the sea floor (echo sounders), map the sea floor and search for sunken objects (sidescan sonars) and to locate fish (fish finders). Sonars of at least one of these types are fitted to nearly all vessels. Even some small boats have fish finding and echo sounders. The characteristics of these sonars are broadly similar to the high frequency military sonars described above.

Arctic Whales and underwater noise

Hi everyone
Just over 4 weeks until I set sail.
The next post will explain more about the Hebridean Whale and Dolphin Watch work, however meanwhile please consider signing the WWF petition for a different ‘noise’ issue for whales - seismic drilling.

Go to support.worldwildlife.org  Protect Arctic Whales from underwater noise.

Thanks