ChrisMcA's picture

Salmon285b

Observed: 7th October 2006 By: ChrisMcAChrisMcA’s reputation in MammalsChrisMcA’s reputation in Mammals
Salmon285b
Salmon286b
Description:

When I posted this salmon, at http://www.ispot.org.uk/node/247775 , it was pointed out, by Peadar na brac & Nightfly, who evidently know what they're talking about (see their remarks)that the 2 slash marks end in holes, & so might be an otter attack, or maybe a seal (ie from their canines). Sadly I didn't get a good fix on the fishes size, but given salmon lice "attain 1 to 3cm",I measured off salmon285b set at "originalsize+" the 2nd fr bottom of the group of 7 lice as 1cm which if = true size makes salmonsize=37+23.5=60.5cm or 23.8 inch; and the canine gap (centre to centre), 1.25in. Sussexotters.org gave gaps of otter=about2in & mink=ab1in. (My hunch the salmon was over 2ft)

Identifications
Species interactions

No interactions present.

Species with which European Otter (Lutra lutra) interacts

Comments

nightfly's picture

Hi Chris, one thought did

Hi Chris,

one thought did occur to me regarding the nature of the bite mark (which I'm certain this is, a mammal bite mark). I have seen punctures with tracks on salmon and sea trout before, fish which have escaaped the grasp of a mammal.

Yours is a good example as there are 2 definite canine puncture and related tracks down the side of the fish.

The thought I am refering to is that the animal which attempted to catch this fish in its mouth had quite a large mouth which it could open wide enough to get its canines right up to the dorsal region of the fish. This might point to an animal with a larger mouth than either otter or mink (both of which have possibly too small a bite to achieve the damage visible here).

I think it could well have been a seal which left these marks on this salmon? The redness of the puncture marks might suggest they are quite fresh and this may well have happened since the fish returned to salt water in recent weeks or even days. Most salmon spawn between mid December and mid January, but some can spawn as late as February, this one was up a river in mid winter (its a male with a kype/hooked jaw, and its leanness tells of its fasting while in freshwater).

Generally when marks are seen on the side of a salmon or sea trout as here, there are corresponding marks on the oppositte side of the fish from the oppositte pair of canines.

Cathal.