Harbour porpoise by Mary Harris

Longhope Harbour Porpoise Project 2022

Ground-breaking research study into Longhope Bay's annual harbour porpoise aggregation

Saturday 17th September 2022 saw the start of an exciting long term research partnership between Orkney Marine Mammal Research Initiative (OMMRI) and Orkney & Shetland Charters who, working together, will utilise land and vessel-based surveys combined with photographic ID work to record the number of harbour porpoises present during the aggregation and analyse their behaviour.

Anecdotal evidence over the last few years estimates that between 150 and 250 harbour porpoises gather together in Longhope Bay area every year. Beginning at the end of August and continuing through to November this gathering (known as an aggregation) is potentially the largest in the UK. Although there are a few theories about why our smallest cetacean might be congregating here in such large numbers no one actually knows the answer; the reasons for this aggregation remain unknown.
With Hazel’s team on board MV Valhalla running transects through Longhope Bay, OMMRI and its trained Stewards of the Sea citizen science volunteers will be undertaking land-based effort surveys from the coastlines of Hoy & Flotta.

The smallest cetacean and only porpoise found in Europe, the harbour porpoise (Phocoena phocoena) is a shy and often elusive animal. In Orkney waters, they are likely the most under-recorded cetacean and their distribution and population size are largely unknown.

The data we collect during this first year of the project will allow us to establish a robust baseline of porpoise presence for the area. The harbour porpoise is a hugely understudied species so this long term project will have significant benefit, not least in terms of supporting statutory authorities and other organisations to make well informed marine planning choices.
- Emma Neave-Webb, OMMRI's science and conservation officer
Harbour porpoise ID by Mary Harris
It's always been a pleasure to observe this wildlife spectacle but, with pressure both on land and sea in the area increasing, we as a community here in Orkney need to study the aggregation to find the answer to a few basic quesions; why here, why at this time of year and for what purpose?
- Hazel Weaver, vessel master and owner of MV Valahalla 

Thank you to this year's funders for helping make this project possible