Spare Cocks?

[exerod]

In the various C&R threads several people have mentioned that the only fish they take are cocks. Is there any science or logic behind the belief that cocks are more expendable than hens, after all a cock is still needed to fertilize the eggs. I know that in a hatchery one cock can be used to cover the eggs of more than one hen but then none of the milt is wasted. In the wild do cock fish mate successfully with more than one hen?

Andy

[Fruin]

I have heard it said that parr can fertilize the eggs of mature hen fish. I do not know if a parr fertilising the eggs would produce weaker adult fish.
From experience of electro-fishing for research and hatchery work, some streams can be almost devoid of hen fish one year and cocks another.
So, in my view, without a thorough knowledge of what ratio of cocks to hens there are in the river in any season, the survival of each can be precious to a sustainable fishery.
All the eggs of the hen fish are no good if you've just killed the only cock fish in a two mile stretch. However, if the numbers are that low, you shouldn't be fishing that stretch

[williegunn]

exerod said:

In the wild do cock fish mate successfully with more than one hen?

Andy

Andy, yes and even some parr can sucessfully fertilise the eggs.

(Graham Ritchie should be able to quote the figure of eggs fertilised by parr I remember him telling me.)

Not much hope for us old males except to die and provide nourishment for the youngsters

[builnacraig]

I think it has been pretty well established that male salmon can and often do spawn with more than one female. The is a good account of this in Alan Youngson and David Hay's book "The Lives of Salmon".

One year 31 males and 56 females were allowed to enter a tributary of the Dee. Using genetic techniques they identified the parents of the eggs in each redd in the spring. One male was found to have spawned at 6 redds with 3 different females and another was found to have spawned in 5 redds also with 3 different females. A high proportion of the matings involved a relatively small number of the males.

Small parr were also involved in successful matings but they usually sneak in from the side, the hen needs the adult male to complete the spawning.

So in answer to your post it makes sense to take the odd male if required for the pot. Each female makes her own contribution to the total eggs laid but a lesser number of males can be adequate to ensure that all the eggs are fertilised.

[altmor]

Like most things in nature, the male of the species can and often does fertilize more than one female, just take a look at the lion and his pride, the bull with a field of cows to himself and for that matter, dance night in Perth. ;D

The cock fish will do everything he can to spawn with as many hens as possible - it is his way of ensuring his genes pass on to the next generation. After cutting in at 3 or 4 redds however, like the rest of us, he'll tend to roll over, exhausted, reducing his chances of making the return to sea, having depleted much of his body weight and energy, the more successful he is at the redds.

[elwyman]

I've read that brown trout can spawn with sea trout, as they are basically the same species.

I wonder if bt/st could spawn with salmon, and if so what the outcome would be?

[elwyman]

graham said:

You can get salmon/trout hybrids, I have caught three of them over the years and have seen another one caught by another angler. They have a mix of salmon and sea trout features and are more common than many people realise. Most people dont look close enough and just pass them off as either a sea trout or a grilse. All the ones I have seen have been in the 3lb to 5lb size bracket and they have all been caught between late July and early September. There is a stuffed one at the salmon research place in Pitlochry.

Is there an obvious way of identifying a hybrid, or do they just seem "different"?

[exerod]

Interesting replies, thankyou.
Although spawning sea trout always have parr and brown trout hanging around them I have yet to see parr on a salmon redd down here. But there again I always go to the very upper reaches to watch salmon spawning so maybe most of the parr have already started to drop downstream in preperation for smolting by the time the adults turn up.

Andy

[elwyman]

Is anybody aware if salmon have actually spawned on their local rivers yet?

I suppose high water will make it difficult to see, but it has been suggested elsewhere that the mild temperatures/ lack of frosts has probably delayed spawning.

[builnacraig]

elwyman said:

Is anybody aware if salmon have actually spawned on their local rivers yet?

I don't know where you are based Elwyman, but even in the south of Scotland most spawning is over by the end of the year. There are always a few spawning in Jan but the bulk of the spawning occurs in December in my area (Ayrshire).

I know from past experience that in the Hebrides (Lewis) it was at its peak in the middle of Nov.

No doubt that the changing climate is going to have an effect though!! Some of the trout in the hatcheries in this area had hatched by the end of Nov, which is very early. There is a danger that they will be emerging ready to feed before the river is ready. Remember the late cold spring we had last year.

[altmor]

builnacraig said:

elwyman said:

Is anybody aware if salmon have actually spawned on their local rivers yet?

No doubt that the changing climate is going to have an effect though!! Some of the trout in the hatcheries in this area had hatched by the end of Nov, which is very early. There is a danger that they will be emerging ready to feed before the river is ready. Remember the late cold spring we had last year.

Only we as Homo Sapiens in the animal kingdom have categorised the seasons by name, eg spring, summer etc. Nature, a far greater and more powerful "keeper" of what happens around us, generally has a way of sorting herself out. Unfortunately, we tend to forget this and plod on with industrial, commercial and political "progress" - I suspect giving her, at times, more than she can cope with.

[kercock]

"Only we as Homo Sapiens in the animal kingdom have categorised the seasons by name, eg spring, summer etc. Nature, a far greater and more powerful "keeper" of what happens around us, generally has a way of sorting herself out. Unfortunately, we tend to forget this and plod on with industrial, commercial and political "progress" - I suspect giving her, at times, more than she can cope with. "
That,is one superb statement. Named that tune in one. !

[altmor]

kercock said:

That,is one superb statement. Named that tune in one. !

Thanks Dennis,

I get one of these about once every 30 years, I reckon I'll have my next when you're ready to retire. ;D ;D
Keep up the good work, you may not realise, but I fished with you this season, and when taping up my joints on setting up, the other Dennis (now retired), asked why I was doing so. I never got your thoughts ?

[exerod]

elwyman said:

Is anybody aware if salmon have actually spawned on their local rivers yet?

I suppose high water will make it difficult to see, but it has been suggested elsewhere that the mild temperatures/ lack of frosts has probably delayed spawning.

Exe fish spawned on time around the end of November and two weeks into December, they don't seem to have got any later. Dorset salmon generally start a bit later, they were going well just before xmas but high water has hidden all activity since then.
Devon sea trout on the rivers I watch are now two weeks to a month later than they were 15 years ago.

Andy

[elwyman]

Interesting stuff Andy.

I'm told conwy fish normally spawn in December. I think the high water has probably helped them get high up the tributaries this season, which is usually regarded as a good thing.

A fish pass was built about 10 years ago to let fish get over some impassable falls. I heard that 100 fish went through it last season, so hopefully this will benefit the river in the long term.

[wilbert]

There seams to be a big surplus of cocks at work, they get called managers, so I am all for a cull on these.

[scotty]

;D