Mark P. Simmonds

The impacts of climate change on marine mammals: early signs of significant problems

Climate change is now known to be affecting the oceans. It is widely anticipated that impacts on marine mammals will be mediated primarily via changes in prey distribution and abundance and that the more mobile (or otherwise adaptable) species may be able to respond to this to some extent. However, the extent of this adaptability is largely unknown. Meanwhile, within the last few years direct observations have been made of several marine mammal populations that illustrate reactions to climate change. These observations indicate that certain species and populations may be especially vulnerable, including those with a limited habitat range, such as the vaquita Phocoena sinus , or those for which sea ice provides an important part of their habitat, such as narwhals Monodon monoceros , bowhead Balaena mysticetus and beluga Delphinapterus leucas whales and polar bears Ursus maritimus . Similarly, there are concerns about those species that migrate to feeding grounds in polar regions because of rapidly changing conditions there, and this includes many baleen whale populations. This review highlights the need to take projected impacts into account in future conservation and management plans, including species assessments. How this should be done in an adequately precautionary manner offers a significant challenge to those involved in such processes, although it is possible to identify at this time at least some species and populations that may be regarded as especially vulnerable. Marine ecosystems modellers and marine mammal experts will need to work together to make such assessments and conservation plans as robust as possible.

Climate change and cetaceans: concerns and recent developments.

At least a quarter of the worlds cetaceans were recently confirmed as endangered and the situation may be worse as the status of many others remains unclear. Climate change is affecting the oceans and a number of studies have recently highlighted its potential impact on cetacean species - for example, there are important linkages between sea ice and krill, the primary prey for baleen whales in Antarctica. This paper provides a synthesis of new information available on this theme and considers its implications for the future conservation and management of cetacean populations and species. The more mobile (or otherwise adaptable) cetaceans may be able to respond to climate related changes, although the extent of this adaptability is largely unknown. However, there is broad agreement that certain species and populations are likely to be especially vulnerable to climate related changes, including those with a limited habitat range, or those for which sea ice provides an important habitat for the cetacean population and/or that of their prey. International conservation bodies, such as the Convention for Migratory Species and the International Whaling Commission, are striving to address these issues. The challenges presented by climate change require an innovative, large scale, long term and multinational response from scientists, conservation managers and decision makers. This response that should encompass a precautionary approach, including addressing the detrimental effects of other factors negatively impacting populations and species.

Potential impacts of climate change and greenhouse gas emissions on Mediterranean marine ecosystems and cetaceans.

The combustion of fossil fuels and the resultant impacts on climate may now represent one of the largest environmental threats. In the Mediterranean Sea, changes in bio-chemical and physical seawater properties resulting from global warming are likely to alter marine biodiversity and productivity, trigger trophic web mismatches and encourage diseases, toxic algal bloom and propagation of thermophilic species. This review highlights the current and potential threats of climate change to the Mediterranean marine ecosystems, including cetaceans, and stresses the emergent necessity for more integrated regulations and policies for the protection of marine biodiversity. For instance, in the Mediterranean Sea, the distribution and abundance of the small euphausid species Meganyctiphanes norvegica is correlated with specific hydrobiological parameters including seawater temperature, salinity and current patterns. Situated at the northern limit of its ecological tolerance, this species, which constitutes the only known food supply of the fin whales (Balaenoptera physalus) in this region, might be affected by climate change-induced alteration of ocean circulation.

Variation in the whistle characteristics of short-beaked common dolphins, Delphinus delphis , at two locations around the British Isles

The vocal repertoire of many delphinid odontocetes includes narrowband tonal whistles used mainly for communication. The aim of this study was to describe the whistle repertoire of short-beaked common dolphins, Delphinus delphis, recorded in the Celtic Sea between May and August 2005. The 1835 whistles recorded were classified into six broad categories and 30 sub-types, of which simple upsweeps and downsweeps were the most common. Furthermore, the parameters duration, inflections, steps and various frequency variables were measured. The whistles covered a frequency span from 3.56 kHz to 23.51 kHz and had durations between 0.05 and 2.02 seconds. Whistle parameters varied with behavioural context, group size and between encounters. The whistle repertoire of Celtic Sea common dolphins was compared to that of D. delphis from the Western Approaches of the English Channel, recorded during a survey between January and March 2004. The relative abundances of the broad whistle types did not differ between the two locations, but most whistle parameters were significantly different: almost all frequency variables measured were significantly higher in English Channel whistles. This may indicate some degree of population structuring of short-beaked common dolphins around Britain. Alternatively, the common dolphins in the English Channel may have shifted the frequencies of their vocalizations up to avoid masking by low-frequency ambient noise produced by high levels of vessel traffic in this area.

Escalation of threats to marine turtles

Many, if not all, marine turtle populations world-wide have become seriously depleted by the impact of numerous factors over the years. Populations of marine turtles are now classified as endangered or threatened. National and international legislation designed to protect sea turtles has been unsuccessful and, despite evergrowing interest, there is disturbing evidence of new and increasingly important threats: increased incidence of disease; oil and organochlorine contamination and marine ‘macro-pollution’.

Is there a conflict between cetacean conservation and marine renewable-energy developments?

There is currently an unprecedented expansion of marine renewable-energy developments, particularly in UK waters. Marine renewable-energy plants are also being developed in many other countries across Europe and in the wider world, including in the USA, Canada, New Zealand and Australia. Large-scale developments, in UK waters, covering thousands of square kilometres are now planned; however, data on the likely impact of this expansion on the 28 cetacean species found in UK waters are lacking, or at best limited. However, the available information, including inferences drawn from the impact of other human activities in the marine environment, indicates a significant risk of negative consequences, with the noise from pile driving highlighted as a major concern. The marine renewable-energy industry will also deploy some novel technologies, such as large submerged turbines, with unknown consequences for marine wildlife. Further research is urgently required, including distributional and behavioural studies, to establish baselines against which any changes may be measured. Precautionary actions, particularly with respect to pile driving, are advocated to minimise impacts on cetaceans.

Behavior of a Solitary Sociable Female Bottlenose Dolphin (Tursiops truncatus) off the Coast of Kent, Southeast England

This article provides a report of the behavior of a solitary sociable dolphin studied on the southeast coast of England in 2007. This is the first study of its kind in which behavior of such a nonhuman animal was systematically studied. By the time of this study, this young female was highly interactive with people in the water. People accompanied the dolphin for 18.4% of the 100 hr of observation, and their presence changed her behavior. The study recorded 39 different behaviors; feeding and resting behaviors declined in frequency in the presence of people. In addition, the dolphin exhibited behavior possibly hazardous to people in the water, which included preventing swimmers from leaving the water. The dolphin received several wounds, at least one of which was life-threatening. This article discusses the welfare implications for such animals.

A note on the unprecedented strandings of 56 deep-diving whales along the UK and Irish coast

In the first seven months of 2008, eighteen Cuviers beaked whales ( Ziphius cavirostris ), four Sowerbys beaked whales ( Mesoplodon bidens ), five unidentified beaked whales and twenty-nine long-finned pilot whales ( Globicephala melas ) were reported stranded in the UK and Ireland. Decomposition of those animals investigated puts the predicted time of death at mid-January. Concerns that an unusual mortality event had taken place prompted further investigations. Most carcasses were too decomposed for necropsy. A summary of findings is presented here. Although the initial stranding of five Cuviers beaked whales in Scotland shared some similarities with atypical mass stranding events linked in time and space to mid-frequency naval sonars, there were two important differences with the remaining strandings during this period. First, the geographical range of the event was very wide and second, the strandings occurred over a prolonged period of several months. Both of these factors could be related to the fact that the mortalities occurred offshore and the carcasses drifted ashore. The cause(s) of this high number of strandings of mixed offshore cetacean species during this period remain undetermined.

Save the whales, not the whalers

The world is poised to cave into demands to resume commercial whaling. How did it come to this?

THE WORLDWIDE EXTENT OF SEISMIC EXPLORATION, 1994–2004

the ships may alter course without constraint. Additional mitigation under these circumstances may be required. Clearly, further research is required to better understand the mechanisms of how sonar might potentially impact on beaked whales. This remains unclear despite a number of theories. Until this time, the RAN will continue to use a precautionary approach. The consultative and innovative approach used by the RAN in managing potential marine mammal interactions demonstrates that meeting environmental compliance standards is possible without undue impact on training. It demonstrates that both the environment and the Navy can be winners.