What is it?

[DavidofMersea]

Just been talking to a mate who was sailing in the Blackwater to day. He was saying that when he was just below the power station he saw about 30 black/brown fish/mammals about a metre long with a dorsal fin - What were they likely to be?

 

[sailorman]

Hbr Porpoise

 

[MoodySabre]

Lucky to see so many. Usual ones or twos when I've seen them.

 

[sailorman]

Lucky to see so many. Usual ones or twos when I've seen them.

agreed, how about Grey Mullet

 

[Cantata]

Quite likely. Or maybe a bunch of dogfish/smoothback/'sharks' as per the press wetting themselves about on the Stour. Thought these were fairly solitary fish, though.

 

[DavidofMersea]

Hbr Porpoise

Wikipedia (which is not 100% reliable) says " They are generally seen as a solitary species.[4] Most of the time, porpoises are either alone or in groups of no more than five animals2 Mine friend saw 25 - 30 of them

 

[DavidofMersea]

agreed, how about Grey Mullet

Grey Mullet don't have a dorsal fin

 

[sailorman]

Hey-Ho

 

[Biggles Wader]

It will be that immigrant species that eats testicles.Spreading like wildfire they are.

 

[DavidofMersea]

Quite likely. Or maybe a bunch of dogfish/smoothback/'sharks' as per the press wetting themselves about on the Stour. Thought these were fairly solitary fish, though.

The physical description fits, but Wikipedia is saying "Spiny dogfish are bottom-dwellers. They are commonly found at depths of around 50-149m", but these were on the surface

 

[guernseyman]

Wikipedia (which is not 100% reliable) says " They are generally seen as a solitary species.[4] Most of the time, porpoises are either alone or in groups of no more than five animals2 Mine friend saw 25 - 30 of them

There were many dozens off the Sept Iles in mid-August; too many to count, possibly 50 or more. Going after the same fish as a huge cloud of sea birds.

Later the same day I saw a couple of dozen 10 miles south of Guernsey in incredibly good viewing conditions. They were illuminated by the sun and visible many metres down as well as being sociable on the surface.

 

[Cantata]

The physical description fits, but Wikipedia is saying "Spiny dogfish are bottom-dwellers. They are commonly found at depths of around 50-149m", but these were on the surface

You don't tend to get those sort of depths in the Thames Estuary!!
Probably up top having a sunbathe.