Norfolk’s grey seals

In Nature, Norfolk, UK
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Grey seals Halichoerus grypus (‘hook-nosed sea pig’ from the Greek derivation) are among the largest animals that we Brits, on our wildlife-depleted Atlantic rock, are likely to encounter. Males weigh around 300kg – approximately the same as one-and-a-fifth land pigs, five washing machines, two pandas or seven-tenths of a horse – with females around half that size.

Male (top) and female with pup

The last UK census, way back in 2000, recorded 124,000 individuals. This was an extraordinary outcome, given that there were around 500 in the early 20th century. This represents a massive 40% and 95% of the world and EU populations of the species, respectively.

Females mate soon after giving birth but development of the fertilised egg is suspended (‘delayed implantation’) so that pups are born at a similar time each winter.

England’s largest colony (rookery) is on the remote Blakeney Point NNR, North Norfolk. In the 2018 breeding season (mostly November-December), 3,012 pups were recorded. This was around 300 more than the 2017 total and three times that of 2012. Temples and Beans Boats run trips to the point from Morston Quay year-round.

There is a smaller, but similarly expanding, rookery in the Horsey-Winterton dune complex, with 2,068 births in 2018. Volunteer wardens from Friends of Horsey Seals, a registered charity born out of the community initiative that replaced a Broads Authority and Natural England project to protect the breeding seals, monitor these more accessible animals. The Friends receive no income from pay and display car parks at Horsey Gap and Winterton, so please contribute generously to their collection buckets.

Pups gain around 2kg in mass per day by gorging on milk with 60% fat content
This female has glaucoma in her right eye, perhaps as the result of an injury. One-eyed seals are thought to be viable in the wild, getting by with one ‘good’ organ.

Disturbance and habitat damage

On New Year’s Day 2019, Winterton Beach and dunes were crammed with hundreds of people. Cars were driven onto fragile verges in order to avoid parking charges, despite prohibiting signage. Adult seals and pups were being harried by dogs and approached within inches for selfies and phone snaps. Sadly, these are not isolated, atypical events. Dogs have attacked and killed several pups, for once justifying local press outrage in this shocking example. There are even reports of parents sitting their offspring on pups to pose for photos.

The animals are vulnerable to disturbance, with risks of abandonment by mothers and attack by territorial males.

The dune systems include rare habitats like lowland coastal heath, which surveys have revealed to be at the very limits of what they can tolerate from ‘anthropogenic erosion’ (trampling). In summer, the beaches fill with day-trippers and tourists. In addition to the seals, these fragile environments also host ground-nesting birds (also regularly killed by unleashed dogs), great-crested newts and natterjack toads, both endangered and protected.

Only around 50% of pups survive their first year.

The Friends’ team of volunteers do their best to prevent harm to breeding seals, assisted by beach closure at Horsey. However, it seems incredible to me that the competent authorities do not appear to have wider systems for a) managing visitor demand, b) enforcing traffic law and, c) protecting wildlife and habitats.

For example, many responsible dog owners would not even consider taking their pets to a beach where there are breeding seals or birds. But others do, and then ignore requests, both written and verbal, to keep them on leads. Similarly, a significant minority of adults and children seem incapable of respecting wildlife and their habitats. In the absence of personal responsibility, I would strongly advocate for – as a minimum – a complete ban on dogs during wildlife breeding seasons and, preferably, visitor management with seasonal beach closures to allow for protection and recovery of our shared natural assets.

Done well, this would generate new eco-tourism opportunities for visitor guiding and information products and services in a manner that protects wildlife while generating value for local communities.

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