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Greetings!
Saturday
(24/October) is World Fish
Migration Day, launched this year as
a one day global celebration to create awareness of the importance of
free-flowing rivers and migratory fish.
I must admit I
would have been hard pushed to name more than three species that migrate
around European waters – Atlantic salmon, European eel and sea trout –
but the map highlights at least four more who are living lives of varying
success.
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The Allis shad
is a mackerel-like fish that lives most of its life at sea, returning to
its natal river to spawn beneath rapids, the only known spawning river in
the UK being the Tamar in the West country. It is doing better elsewhere,
mostly in French waters. A bit grayling-like in appearance the
status of the houting, a member of the salmon family, is contentious.
There has been €20 million project to restore the Danish houting but
there is some argument whether this is a ‘true’ houting; if it isn’t the
species is classified as extinct. On the other hand, the Vimba bream that
migrates from the Baltic into the rivers of Eastern Europe and Russia is
doing well.
The largest of
our migrants is the Atlantic sturgeon that may grow as long as 20 feet,
reach 800 pounds in weight and doesn’t reach sexual maturity until around
15 years of age, living as long as 60 years. Until a few centuries ago Acipenser
sturio was commonly found in British rivers such as the Severn, Avon,
Ouse, some Scottish rivers and the Thames, so much so that under UK law
the sturgeon, along with whales, are classified as ‘Royal fish’ and
therefore property of the Queen. However, since the last one was caught in
2013 (probably a discarded pet) don’t expect sturgeon on the menu anytime
soon when you dine at Buckingham Palace.
Unlike many
fish, sturgeon was not exploited until relatively recently; for the most
part it was considered worthless, at best avoided, as its rough skin
shredded fishing nets. However, once its value for caviar was recognised,
along with its leathery skin used in clothing and bookbinding, and the
blubber processed into isinglass, a gelatinous substance used in
clarifying jellies, glues, wines and beer, its days were to be numbered.
Today there are
estimated to be at most 750 mature adults living, with the sole spawning
site being the Garonne River in France, where it last spawned in 1994 so
it is, unsurprisingly, on the Critically Endangered list.
If you would
like to know more, watch the Love Flows film or participate in World Fish
Migration Day with 300+ online events click here ....
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A
Russian 40 Kopek stamp from 1959 featuring the Atlantic sturgeon
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Alaska to New Zealand non-stop
Did you read
about 4BBRW? The name does not give you much clue as to what or who 4BBRW
is, but it is in fact a godwit, a bird that splits its life between the
sub-polar extremes of our two hemispheres, migrating between its summer
haunt of Alaska and New Zealand.
Last month this
particular Bar-tailed godwit, which weighs no more than a pound (it eats
to double its normal weight in preparation of the journey) set the record
for the longest non-stop migration on record, flying the 7,456 miles in
11 days. How did our godwit do it? After all, the journey is almost
entirely over the Pacific Ocean for a bird with no capacity to feed, rest
in water or sleep on the wing.
Well, despite
what you might think, it doesn’t take the most direct route. The godwit
clearly has some sort of avian algorithm that allows it to navigate the
route by hitching a ride on the most favourable winds whilst anticipating
approaching high and low weather fronts.
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It is surprising
how many birds migrate; it is estimated worldwide about 4,000 do so,
which is 40% of all species, in the search of better feeding and breeding
grounds. However, in the UK we are way below that percentage which, I
guess, speaks to our relatively benign climate with only around 70
migrants amongst the 574 that live here for all or part of the year. I’ve
struggled to find any British bird that matches the godwit for travelling
but the Willow Warbler makes a fine effort for such a small bird arriving
as it does from Southern Africa in late spring having flown 5,000 miles
over mountains, deserts and seas.
How do the
Willow Warblers and their like find their way on a route that they are
often charting both alone and for the first time? Scientists think that
birds use their sense of smell to follow odours, their remarkable
eyesight to follow the Sun, the stars, the Earth's magnetic field, and
landmarks, and wind directions to achieve navigation. And a bit like the
European eel, just to mix things up, the return trip can often follow an
entirely different route.
And why do they
travel at all? Well, obviously avoiding the extremes of climate is a
motivator but the length of the day, scarcity of nesting sites, easy
availability of food and predators have all aggregated over time so birds
seek the best way of preserving their particular tribe, even if it
involves massive relocation with all the risks that that entails. But
then again migration is not always a baked in evolutionary strategy.
Sometimes it is driven by necessity, irruptions as they are called, when
birds flee their native land when a primary source of food fails. For the
recipient land these are more invasions than migrations, such as when
Waxwings appear along the east coast of the British Isles, in the wake of
the occasional failure of the Scandinavian rowan berry crop.
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Where is the Piddle valley?
I was delighted
to see that Nether Wallop made it on to the UK map of the weirdest,
silliest, oddest and rudest place names that was doing the rounds on
social media last week.
Rivers usually
provide a thick seam for cartographical mischief makers so I was
surprised that Dorset’s Piddle valley didn’t make the cut. As any
schoolboy will attend, it is a glaring omission.
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Video of the week
I know you all
like a bit of fishing action and the trailer for the International Fly
Fishing Film Festival is a great opener for the weekend.
It has been
around for a while but as far as I know, thanks to Covid, the live 2020
screening never made it to our shores. So, enjoy the trailer (love that polar bear) and if you look
down the righthand side of Vimeo there are a dozen more trailers which
are great fun in themselves.
If you are keen
to watch the whole show it is being released for 48 hours on December 3rd.
A single pass is $15 or $30 for a group. Get in the beers and make it a
party! More details here …..
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