Yesterday’s post on the shooting of seals and the use of scaring devices attracted a lot of interest, having been read by around 600 people up to now. The link was also posted on Twitter, which provoked some responses.
The parties to the following exchange were Kenneth McNab of the Clyde Fishermens Association, the doyen of the Clyde fishing fleet and someone I greatly respect for what he’s done for the Tarbert community over the years, (KMcN), Arthur Scargill, who really needs no introduction (AS) and myself (EGK).
“(KMcN): I find it strange that in among all that waffle there is no reference as to why the seal population is increasing at an alarming rate. This is very worrying as the seal is by far the biggest predator to all other species under threat and may become extinct down to the seal
EGK: Or possibly shifting their habitats? Is it possible that grey seals are shifting to more inshore locations? Their rates of reproduction seem relatively static. Serious question whether anything can/should be done compliant with UK and US regs. What do you suggest?
KMcN: Seal numbers are increasing all over the west coast and in Ireland inshore and offshore . Research has already been done in Strathclyde uni on how they have affected cod stocks on the west coast . Equivalent of deer on the hills if left will end in tears
EGK: ... I’d like to read that. I entirely agree about the deer, by the way.
AS: No vague or trivial matters here, this is very informative for those who are not as involved.
Please quote the source of the “alarming” seal increase.
Please quote the source of the “alarming” seal increase.
KMcN: Strathclyde University Prof Robin Cook
AS: Cod. So what has this got to do with the current bill change to align with US welfare laws?
EGK: Nothing to do with US welfare laws, but underlines that whatever else is tried to reduce any impacts shooting isn't an option.
K McN: I didn’t say it had.
The article said there were less seals could you give me your evidence
EGK: The link to the study is here: Strathclyde University You will see that they found the economic impact relatively minimal and balanced against revenue from other sources, e.g. tourism, which is the main driver of coastal economies.
I was puzzled at the "alarming increase" because grey seals breed once per year and usually produce one pup. The Strathclyde University study showed that while there was an increase after 1980 the population is now steady at around 30,000, which is why I suggested they might be moving their habitats, which would explain an increase in one area above what would be naturally possible. Need to check if SNH have done another helicopter survey recently.
KMcN: They more than likely have given someone a grant to do it to get the desired outcome
KMcN: Your group campaigns for the recovery of demersal stocks yet you don’t want to do anything about the biggest predator then you say the tourism economy is more important is that not a bit selfish I thought conservation was at the heart of your group”
Just to clarify, the group that I’m only part of is simply the several thousand of us along the coast who are interested in and campaigning about the environment. I have no interest in the tourism industry, but it’s a fact that it’s the main economic driver, as I wrote.
A year or so I had another exchange with Kenneth in relation to grey seal populations, which do indeed seem to be growing around the Clyde.
I duly obtained data from SNH under Freedom of Information. It turned out that there is in fact a great deal of information being collected pretty constantly on seal populations. The link below should direct you to a report from 2018 from the Scottish Oceans Institute at St Andrews University. It’s a very comprehensive crash course for anyone who wants to know about seals. From the mass of detail I’ve extracted a few details that I think are useful.
The United Kingdom is currently home to about 38% of the World grey seal population and about 88% of those live in Scotland. As at 2015/17 the Scottish population was about 150,000, mainly concentrated in the Outer Hebrides and Orkney. There are about 30,000 on the west coast.
Mature females, from about five years of age, will typically produce one pup per year. Survival then depends on the nature of the haul-out. Overall this has resulted in a slow yearly rise in the overall population.
Mature adults weigh up to about 300 kg and eat between 4 kg and 7 kg per day.
The survey does not indicate any breeding sites in the Firth of Clyde, but plainly there must be some, as it’s extremely unlikely that grey seals from, say, the North west corner of Mull, would be venturing round the Mull of Kintyre and foraging in the Firth of Clyde.
The following that came from the Bute Museum is interesting, but extremely out of date:
“Grey Seal Halichoerus grypus
(UK: Native, common and widespread around the coast.)
(UK: Native, common and widespread around the coast.)
Gibson (1970) recorded seeing two Grey Seals in the sea south of Garroch Head in early May 1967. This is the first recorded sighting of Grey Seal within Bute waters. However by 1976 Jack Gibson was able to report that ‘within the last five years Grey Seals have been seen very regularly just off Bute shores, particularly around Garroch Head and other parts of south Bute’. Gibson had also by then seen Grey Seals between Bute and Inchmarnock and been told of sightings near Rhubodach.
In 1990 Gibson reported that in contrast with Common Seal, within the previous 15 years the Grey Seal, once quite rare in the Clyde, had become widely and commonly distributed throughout the entire Clyde sea area and that the population had increased dramatically. On Bute there were by 1990 regular gatherings of Grey Seals at Garroch Head throughout the year and the species was being seen commonly offshore at many places, around the south, off Rhubodach, down the west Kyles and near the north-west of Inchmarnock.
Grey Seal pup production is used to estimate the total size of the British population. Since pup production monitoring started in the 1960’s the number of pups born throughout Britain each year has increased consistently, in Scotland alone the average annual pup production increased by 2.2% between 2005 and 2010. However in recent years a significant reduction in the rate of increase in pup production has been seen, this is clear evidence that growth is levelling off (SMRU, 2011).
Locally, Grey Seal has possibly increased further in numbers since 1990, being now fairly common around all Bute shores, although continuing to be outnumbered by Common Seal, but see the comments under Common Seal, including Billy Shields’s count in 2009 of 156 seals at Scalpsie Bay, the majority of which were Grey Seals. On 14th July 1991, Ian Hopkins counted a group of 8 hauled out at Garroch Head and on 18th August 2000 he counted 7 at Bruchag Point.
In May 2009 Billy Shields obtained a photo of a seal pup with an umbilical cord, at Scalpsie Bay, where it had obviously recently been born. Although more often than not, Grey Seals give birth, in the early months of winter, Jane Dodd, the Marine Project Officer at SNH, identified it as a Grey Seal pup.”
In 1990 Gibson reported that in contrast with Common Seal, within the previous 15 years the Grey Seal, once quite rare in the Clyde, had become widely and commonly distributed throughout the entire Clyde sea area and that the population had increased dramatically. On Bute there were by 1990 regular gatherings of Grey Seals at Garroch Head throughout the year and the species was being seen commonly offshore at many places, around the south, off Rhubodach, down the west Kyles and near the north-west of Inchmarnock.
Grey Seal pup production is used to estimate the total size of the British population. Since pup production monitoring started in the 1960’s the number of pups born throughout Britain each year has increased consistently, in Scotland alone the average annual pup production increased by 2.2% between 2005 and 2010. However in recent years a significant reduction in the rate of increase in pup production has been seen, this is clear evidence that growth is levelling off (SMRU, 2011).
Locally, Grey Seal has possibly increased further in numbers since 1990, being now fairly common around all Bute shores, although continuing to be outnumbered by Common Seal, but see the comments under Common Seal, including Billy Shields’s count in 2009 of 156 seals at Scalpsie Bay, the majority of which were Grey Seals. On 14th July 1991, Ian Hopkins counted a group of 8 hauled out at Garroch Head and on 18th August 2000 he counted 7 at Bruchag Point.
In May 2009 Billy Shields obtained a photo of a seal pup with an umbilical cord, at Scalpsie Bay, where it had obviously recently been born. Although more often than not, Grey Seals give birth, in the early months of winter, Jane Dodd, the Marine Project Officer at SNH, identified it as a Grey Seal pup.”
What this all suggests is that there may be an information vacuum regarding the inshore populations and the extent to which grey seals are migrating. This would be bad news for the smaller harbour, or common, seals, as the greys victimise them and compete for food. They number only about 26,600 in Scotland and are far more endangered. Main causes of decline include being more exposed to toxins and pollution, entanglement in debris, and being shot by fish farms.
To summarise, there is no evidence of an “alarming increase” in grey seal numbers, but there may be local migrations. I shall write to St Andrews University and suggest that the next survey should look specifically at the Firth of Clyde.
What’s clear is that given the protected status of seals internationally and the concentrations in Scottish waters there is no chance of controlling populations by shooting them.
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