National Mammal Week 2020 Day 3: Coast & Sea
Mammal Society Science Officer Frazer Coomber talks about some of the marine mammals you might be lucky enough to spot. Frazer’s background and PhD were in marine mammal surveying where he studied the impact of underwater noise on the distribution of whales.
Cetaceans – focus group, no field signs
Habitat – no field signs
Other mammals – seals and otters
The coastal and marine environment around the British Isles is home to a variety of marine mammal species, from cetaceans (whales, dolphins and porpoises), to seals and otters. Some of these species live and feed far from the British coast and because of this, are rarely seen by people. For instance, Cuvier’s beaked and sperm whales, typically frequent deep (1,000 m plus) waters off and around the continental shelf, hunting at great depths for deep water squid. Some cetacean species may live off our coast all year round and some are migratory, passing through our waters as they travel from breeding grounds to feeding areas and vice versa. However, it is still possible to watch for whales and dolphins from the coast with countless great spots across the UK. Headlands and/or inshore boat trips on calm days provide some of the best viewing opportunities for these species.
Some species that you may come across in coastal waters include the harbour porpoise, bottlenose dolphin and the minke whale. Cetacean species are often inconspicuous as they spend a large proportion of their time underwater, obscured from any observers. However, these air-breathing mammals routinely come to the surface to breathe and it is then that we get a chance to observe these majestic animals. On the surface, many cetaceans have highly characteristic surfacing profiles, with a dark or glistening back and dorsal fin that rolls through the water. The animal’s shape, size and position of the dorsal fin can be used to identify which species you have seen. For instance, the harbour porpoise is small (roughly 1.8 m in length) with a distinctive triangular dorsal fin set centrally on the back. The minke whale, in comparison is much larger (just under 10 m in length) with a small (relative to the animal’s size) recurved dorsal fin set 2/3rds of the way along the back.
These species share their British coastal and marine habitat with two seal species; the harbour and grey seals, and the European otter. Although these species can occasionally be mistaken for whales and dolphins, they lack a dorsal fin and can also be seen returning to land.
Many human towns and cities are situated along the coast and this has led to increased anthropogenic pressures on the marine environment. These pressures can have detrimental effects on cetacean behaviour and physiology. These pressures include increased pollution, in the form of plastics, chemicals and even underwater sound, incidental bycatch and disturbance from marine traffic.
How Can You Help?
Anyone can help cetaceans by reporting sightings or by helping to reduce disturbance to these animals in their natural habitat. Biological records – a record of what, where and when a cetacean was seen – can be submitted to a variety of cetacean recording schemes around the UK and these records can help us to understand where these species occur. This is also true for dead or stranded animals. The UK has several stranding schemes (e.g. the UK Cetacean Stranding Investigation Scheme – CSIP – https://ukstrandings.org/) that record where and when a stranded cetacean is found. Furthermore, people can help by reducing the impact of disturbance by observing animals in a sensitive manner. Such as following guidelines, such as Wise (Wildlife Safe – https://www.wisescheme.org/) in order to observe these species in a manner that keeps disturbance to a minimum.