Farrar River, Highlands Scotland 1996
1. It there exists a significant difference in the time of spawning between populations spawning in the headwaters and those located in the middle and lower river sections. By early November all the spawning in the high parts of the Farrar river and its tributary Misgeach Burn (Scottish Highlands) had ceased. We did find dead fish and kelts in these areas at the beginning of November.
2. The spawning activity during the the sunrise and the hours after sunrise has been in this Farrar area null. We started working most of the days about six or seven in the morning, but no fish came to the redds until half past ten or eleven. The hypothesis, not proved, that come to my mind is that salmon does not want to be conspicuous at those times when the activity of their egg predators is maximum (i.e., heron and dipper).
3. The females may cut several false redds. We observed females, mainly grilse, cutting redds in areas that we believe were not the appropriate; either by the substrate composition or by the water current. In these cases we observed that these females finally completely abandoned their nests.
4. The females spent long time periods away from their redds. The spawning activity was generally compressed in short time intervals of about 2 hours and then ceased for longer periods of time.
5. The bird commonly named
dipper, Cinclus cinclus, has been for us like a definitive signal for finding
either old or active redds.
Nansa River, Cantabria Spain 1997
Before the actual spawning we notice the following:
1. The female stays permanently in a “probing” position.
2. The respiratory frequency and intensity of both female an dominant male increases some minutes before oviposition.
3. Prior to spawning the females removes vigorously her anal fin into the gravel.
4. The female starts the spawning gap some fractions of a second before the male.
5. The frequency and intensity of attacks between adults have increased significantly some minutes before oviposition.
Asturias, Cantabria 1998
1. From our observations during this season we presume that it is relatively frequent that salmon and trout (almost always sea trout) get mixed during the spawning courtship . We recorded in the Cares River sea trout performing quiverings to a grilse female. We do also recorded in Nansa River a salmon male making quiverings to a sea trout (that we believe were also a male!).
2. Fishes of different sea ages get also mixed during the spawning in a single redd. We saw in the Cares River a grilse female being courted by at least three multi sea winter males.
3. Females do prevent males to spawn by moving vertically away from the redd when while quivering their bodies males approaches them .
4. From our observations we do also presume that males does not show a selective sexual behaviour. Instead they seem to be blind by their sexual instinct. We have at least recorded three males performing quiverings to our underwater camera without any female in the redd. We do also have seen, as explained above, males quivering to sea trout males.
5. We have observed
in Nansa River that one female has replaced the position of another female
in the same redd without having any fight. We have observed the same
with trout from the Pyrenees Mountains. In that sense we do believe
that it will be very interesting to test a null hypothesis saying something
like: "Atlantic salmon females do not cooperate between them during nest
1. The period of time between the moment the female arrives to the nest until oviposition can be hours or just minutes. We want to say that the fact that one female arrives to a nest wont tell us how far is the spawning moment. For knowing that mainly we need to know in which conditions the nest and the female are. In the Killachy Burn (Findhorn tributary) a female spawned after just 14 minutes of arriving to a nest that we have been followed during hours.
2. Once the female has laid
her eggs and covered them, she can immediately start a new nest in the
same or other redd.
In the Killachy Burn we did observe how after she finished covering her eggs, she started excavating a nest, which we didn't know if it was new or not.
3. A female after laying her eggs can be courted by the same or by different males. After the Killachy spawning we observe a new male courting the female.
4. Contrary at we have
read in the scientific literature we did observe not spawning activity
in periods of river high flow. We understand that this observation
can be due to:
a. The high river flow and the low water visibility does not allow us to see any fish.
b. It could be really more economically in terms of energy for a fish to stay in a covered position.
I do think this second point is more probable. It is difficult for me to think in a salmon female guarding and periodically excavating her nest while extreme or very high flow water conditions.
5. In small burns or
tributaries the spawning period will always be much shorter than in the
bigger rivers where the systems are more stable.
Asturias, Cantabria 1999
1. A great number of fights for the salmon female can be solve by the males using "displays positions" instead of actually physically fighting.
2. We have observed that when there are only salmon males in the redd the precocious par will many times behave depending upon them. It is very frequent that even maintaining a hidden position the precocious parr will follow the male or males when they abandoned the nest. This wont be occurring when a female is present.
3. Male competition and the presence of various females delays all the spawning period. In occasions when we have only have seen a pair of fishes all the spawning has been completed in hours. In opposition, when there were a lot of fish in the redds spawning will normally last for a week or more.
4. Contrary at we have
read in some general ornithologists manuals, the dipper, Cinclus cinclus
juvenile fish. During November 1999 I did video recorded in the Puron
River (Asturias) the bird capturing and eating fish. The fact that
only two weeks prior to those recording a massive escapement of rainbow
parr have occurred from a very near hatchery induces me to think that I
was being witness of a "local adaptation". The tremendous trout
abundance in the river and the lack of "predatory avoidance" for the hatchery
fishes could be two reasons to make stronger the "local adaptation" idea.
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