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Río Matarranya, Spain

Home Forums Field Trips & Conservation Río Matarranya, Spain

Viewing 7 posts - 16 through 22 (of 22 total)
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  • #349016

    coelacanth
    Participant

    @Matt said:
    P.S. as for the rods – still useful if one has no clue what to do with them? :p

     

    Never stopped me before….

    There has been a fair bit of stocking done around the place with these things, although it’s always where there is an established history of angling. It’s perfectly possible that the same stocks of Salmo trutta sensu lato that produced them further North also left a population where you were, isolated as the lower altitudes warmed and became Salmonid-hostile.

    #349020

    Matt
    Keymaster

    Heh might just give it a go – certainly appeals more than squatting by a murky canal with a fag and can of super.

    Been doing some research and the checklists for the Matarranya do have records for Salmo trutta in the upper basin but the most interesting stuff was in Kottelat and Freyhof’s ‘Handbook of European Freshwater Fishes’ who note that trout retaining parr marks in adults are known from Iberian Peninsula, northern Pyrenees, Corsica, Sardinia, southern Italy, Greece, Turkey, Algerian, and Morocco and all have been grouped together under Salmo macrostigma in the past.

    Among other things they also say that Mediterranean trouts belong to very distinct lineages compared with Atlantic and Danubian ones, that the name S. macrostigma can only be used for some N. African species, and that those with parr marks occurring in France and Spain (Ebro River in the latter) ‘apparently represent several distinct, unnamed and unstudied species’. The name S. cettii is given to the populations from Italy and Corsica.

    Maybe the zebra trout is one of these parr mark-retaining forms?

    #349021

    Matt
    Keymaster

    So the next morning we decided to check out the Río Algars which flows out of the adjacent valley before joining the Matarranya a bit lower down. Lots more Parachondrostoma miegii here, and some wonderful scenery.

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    #349022

    Matt
    Keymaster

    Final stop was the village of Fabara some 50 km downstream, in the middle part of the river. It was pretty dry here too but there were still loads of fishes including the by-now ubiquitous P. miegii and best of all the ‘bermejuela’, Achondrostoma arcasii.

    This is a small fish growing to around 100 mm SL and I’d been looking for it since moving to Spain so it was great to finally catch some. Will try to get back in spring and look for males in spawning colouration as they should be quite something.

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    #349024

    coelacanth
    Participant

    @Matt said:
    Maybe the zebra trout is one of these parr mark-retaining forms?

     

    Looking at the pictures elsewhere, they are, but then again I’ve had small-stream brownies on more than one occasion that also retained parr marks in spite of being mature fish, so I personally would be interested to see whether retention of parr marks is simply a sign of a small-maturing population/individual. Larger zebra trout don’t seem to have the parr marks (this is from a limited set of pictures I’ve been able to find), just like larger brownies. The dark pigmentation that makes up the stripes in a zebra trout does appear to be separate from the parr markings, they look like a different set of chromatophores to me.

    Avoid looking at the Brown Trouts. I scratched the surface and it made my head hurt very quickly. Multiple radiations, multiple climatic events, phenotypic plasticity. 

    #349028

    Matt
    Keymaster

    Yeah I got that feeling from Kottelat and Freyhof. Some individual fish even change from river resident to amphidromous a few years through their life cycle. :-/

    Regarding the parr marks, I see what you’re saying. These zebra trout have three main ‘blocks’ of dark pigment on the body whereas parr marks are smaller and more numerous yes?

    #349030

    coelacanth
    Participant

    Yeah I got that feeling from Kottelat and Freyhof. Some individual fish even change from river resident to amphidromous a few years through their life cycle. :-/

    Aye, various developmental thresholds are in play.

    Regarding the parr marks, I see what you’re saying. These zebra trout have three main ‘blocks’ of dark pigment on the body whereas parr marks are smaller and more numerous yes?

    Yep, see here http://www.atlanticsalmontrust.org/knowledge/salmon-and-sea-trout-recognition.html

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