May18

Ocean Nomads: Unlikely visitors to our waters

Author // James Robbins Categories // Whale & Dolphin General News

Ocean Nomads: Unlikely visitors to our waters

We've had some really unusual sightings in 2018, but why do some species end up in our area?

The last months have seen an array of unusual marine mammal sightings, ranging from a wandering walrus in Scotland to an out of the ordinary orca in the North Sea.

But what are some of the reasons for seeing the nomads in nature?

The factors affecting species distribution are incredibly diverse, with small changes having a potentially significant impact on both individuals and groups.

Food source is high on the list, with any change to prey in an area resulting in often dramatic shifts for predator species. Whether prey animals distribution changes or whether the population collapses, a shift in the availability of food can have a catastrophic impact.

Closely linked to this is temperature change in the ocean and temperature anomalies can see unusual distributions of species. Globally, sea temperatures are changing and this is having a profound impact on different habitats, affecting the flora and fauna in a particular sea region and sometimes resulting in large shifts in species distribution. For example, lower sea surface temperatures in Arctic waters would potentially see walruses heading further south from their traditional ranges.

Human activity can also play a role – offshore energy production, shipping and fishing all create huge changes in an individual ecosystem and as a result animals, both individually and as groups, may be forced to explore new habitats as a result. We still don't understand enough about the impact of offshore infrastructure so it's imperative we treat these delicate ecosystems with respect.

There are also some individual factors that can play a part too. Sickness or injury can result in animals being disorientated and result in them getting lost. Sometimes this is due to natural illness, and sometimes it can be through pollution or marine litter causing toxicity or starvation that sees animals turning up in unexpected places.

Of course sometimes it is just a case of animals taking a wrong turn and getting lost – though they are incredibly intelligent animals, they are far from perfect and younger animals in particular are sometimes just heading into the wrong part of the ocean!

Understanding where species can be found is incredibly important in ensuring a safer future, and ORCA’s monitoring work is crucial in establishing a base line to better understand some of these rarer encounters, playing a crucial role in conservation management policy and allowing lawmakers to make informed decisions.

To find out more about individual species, check out our The State of European Cetaceans Report to see what we’ve learnt about the most commonly seen species in UK & European waters.