The return of the giants - humpback whales in Scottish seas
6 April 2018 - 11:05am
Ron Macdonald retired from Scottish Natural Heritage (SNH) after 27 years of service. SNH is the public body that advises the Scottish government on wildlife and environment. A biologist by profession, he says that his interest in the humpback whale is as much spiritual as ecological. In this guest blog he shares his passion for watching humpbacks whales and what he’s finding out about their comeback to Scotland's seas the seas around Scotland. (Guest blogs do not necessarily reflect the views of WDC)
I’m besotted by humpback whales, ever since 2016 when two came barging and breaching into the Ythan estuary here beside my village of Newbugh-on-Ythan in Aberdeenshire. So much so that friends say I have WAD - whale affective disorder - which, when humpbacks are about, sees me not eating or sleeping particularly well, not walking our dog enough - (our ‘Mac’ looks at me mournfully to increase my guilt), and speaking to and answering myself. This whale watching malarkey is addictive!
So with this in mind, I’ve just spent an enjoyable time observing humpback whales in Firth of Forth, in the ancient kingdom of Fife, looking across the water to the island of Inchkeith and beyond to Edinburgh in the far distance. Here, from early January to late February, up to three and possibly more humpback whales feasted on shoals of fish, likely to be herring and/or sprats. They were here at the same time last year. Is this coincidence or are we seeing a wider increase in humpback numbers in Scotland’s seas? Are the ‘giants’ returning and if so why?
With access to Whale and Dolphin Conservation and the Seawatch Foundation data I have been looking at the number and distribution of humpback sightings off Scotland. This graph shows the beginnings of a recovery in the 1990s which petered out, but sightings increased in the mid 2000s to the present day. Undoubtedly the rise in the use of social media has led to an increase in awareness of the importance of reporting sightings so we need to consider this when interpreting the data. Nonetheless the trend looks pretty convincing that the ‘giants’ are making a comeback.
The distribution of sightings is concentrated in a few hot-spots: on the east coast from Montrose to the Ythan estuary, north of Aberdeen; the Moray Firth; the Northern and Western Isles; the Minch; the Clyde and the Firth of Forth. Some of these were of the same individual humpbacks returning to the same area in consecutive years. Humpbacks are faithful to known feeding areas as shown by one of the humpbacks seen in the Firth of Forth in 2017 returning this year and one of the humpbacks observed off the Aberdeenshire coast in 2016 returning in 2017.
Looking more closely at one of these hot-spots, this map of the sea off Tiumpan Head, some 11 miles north east of Stornoway on the Isle of Lewis, shows the distribution of humpback sightings by the local WDC Shorewatch team. Delving into when humpback whales appear off Lewis, a seasonal pattern emerges. In late autumn and winter (October to March) and again in early to mid-summer (May to July) you are likely to see more humpbacks.
In looking for possible clues I talked to a Norwegian project which, since 2016, has been following the migration of humpback whales from their feeding grounds off Tromso to their breeding grounds in the Caribbean. Most of the observed humpbacks passed close to the Northern and Western Isles so is it possible that we are seeing some of these en-route to their southern breeding grounds? The protracted autumn winter peak in numbers coincides with their southward migration as does the summer peak when they return north to their feeding grounds in the northern North East Atlantic, the northern North Sea and Barents Sea.
An alternative explanation is we are simply seeing an increasing number of humpback whales in our seas. We know that globally, populations of humpbacks are generally increasing at anything between two and 11% per annum brought about by a recovery from commercial whaling, possible expansion of the area they travel through and improved availability of food. Could it be that what we are seeing are ‘newcomers’ to British waters testing the water so to speak. Certainly there is evidence of a sustained recovery in sand eel populations in the northern and central north sea and similarly a recovery in herring populations in places like the Minch and the Firth of Forth.
Implications for Fishery Management
The management of Scotland's seas, and in particular the management of its fisheries, is at a turning point with the UK leaving the European Union. In as much as there is an undertaking by the Scottish government to retain the environmental regulatory standards as present, it's yet unclear how this will be translated into UK and/or Scottish law.
What is welcome is the forthcoming consultation on four more proposed marine protected areas (MPAs) in Scottish waters, hopefully by the end of 2018 – something WDC and other marine NGOs have been campaigning for over many years. These are aimed at protecting some of Scotland's most charismatic marine life including wide-ranging species such as minke whales, Risso's dolphins and basking sharks. All four of the sites have the potential to protect humpback whales who are increasingly visiting our waters, and fulfil our international responsibilities in safeguarding the whales, dolphins and porpoises who feed and breed throughout the North Atlantic. In particular, the North East Lewis proposed MPA should protect the important sand eel populations that Risso's dolphins feed on during the summer and autumn. As the site is probably the single most important location for humpback whales in Scottish and UK waters, hopefully the species will be considered as a priority marine feature in the proposed MPA. With any luck, other sites, such as the Firth of Forth, will also be considered as new information about their importance for summering and wintering humpback whales comes to light.
I also welcome the February decision by the Scottish government to fund a project, led by Scottish Natural Heritage, and involving WDC, to investigate the risk of accidental entanglement of whales, dolphins and porpoises in fishing gear, principally ropes from lobster and crab creels. What is particularly welcome is that it is a partnership project involving fishing, environmental and welfare bodies. A 2016 International Whaling Commission study, using information from strandings and live entanglements, concluded that Scotland is presently acting as a mortality sink for humpbacks which is undermining their continued recovery in our waters. This worrying conclusion has been questioned by some scientists so this latest study will gather further evidence on which to base a strategy and management plan to avoid and mitigate the entanglement risk. Nobody wishes to see whales, dolphins and porpoises entangled, least of all our fishermen who are to the fore in the new study.
So I'd like to end by saying that Scotland is enjoying the return of the humpback whale in our seas. The reasons for this are likely to be due to several factors - population recovery following the ending of commercial whaling in the North Atlantic, improved stocks of their prey fish and possibly range expansion and migration close to out shores. Whatever the reason, there is every chance my WAD is treatable. The future looks bright for the return of the giants.