Monday, 4 February 2013

Salmon eat or do not eat in rivers/freshwater

Salmon eat or do not eat in rivers/freshwater
Based on the Stanislaw Cios reports. 

It is believed that salmon, enter the rivers to spawn, stops eating for as long as again returns to the sea. This dogma is not objectionable as long as not to deal with phenomena that do not fit into its framework. The more somebody has a need to try to justify the effectiveness of realistic fishing salmon flies. Behavior of salmon in fresh water has long been an interest, and some of this information may speak in favor of this point of view.

These pictures I made in 2005 on the river Chavanga, please forgive me for the excessive naturalism of these photos. 

The salmon was caught in August, on the river Chavanga. Judging by the color, it was in the river for at least 2 - 3 months. Patency of the esophagus is preserved, the liver is in order, the gall bladder is full, the stomach without any changes. 

In the discussion of controversial topics, you need to properly and accurately articulate the scope conversation:

Eats a salmon in the river, being in it all the time?

It is a salmon (Salmo salar) in the river. Excluded from the affairs of trout (Salmo trutta m.trutta), cases of possible re-entry into the sea and the data obtained at close to the mouth of rivers.
Unfortunately, the full research on this topic has not been done. There is work as sea trout entering the river to spawn. On property salmon very fragmentary data are scattered in different sources. However, this information can be divided into two parts.
1. One part concerns the observation of the behavior of salmon, visually fixed-tant facts "hunting", eating salmon living objects.
2. The other part contains the anatomical studies of internal salmon and detection of "living" organisms, and more.
 I wanted to share this information as the "direct and indirect" signs of power. For example, the presence of caddis in the stomach considered as a direct sign, proof supply. In fact, things were more complicated and the interpretation of each "apparent" case can be ambiguous. More on that later.
Watching salmon to supply circumstantial evidence can be attributed to the interest or rather a reaction to:
- Dry flies that imitate mayflies and caddis flies. There are several books, which describes a similar catch. For example, Wood (1924) refers to the book ERHewitt «Secrets of the salmon», in which he describes the numerous cases of salmon caught on a dry fly. Including the March Brown. When the salmon fishing has seen, he collected flies as do the large trout. The author also points to the high efficiency of small wet flies, which are directly under the water surface.
- Live insects. In his letter, Doorly (1959) mentions Caught DAP-ping on the May live ephemera 3 kg salmon. His stomach was a lot of these insects. Nall (1930) argues that "there are a lot of facts" collection rities salmon feed on the surface, winged insects and caterpillars. He had witnessed this on the River Lyon (inflow r.Tay).
- Vertebrates, particularly in fish and amphibians. Describes the frequent cases of attacks, ends swallowing small fish. As examples of the victims are small fry, minnows and frogs.

About the contents of the digestive system known salmon is not very much. St.Cios based on data collected in 1933 and professor S.Zarnecki their own bibliographic discoveries made the table, which is a short form provided here. I intentionally present this venerable table and other similar properties published data. The fact that the interest in this topic is old but certainly elsewhere have fresh data.

         By River Number of investigations results

Mc Intosh 1863 Tay, of Great Tania
  About a hundred in 10 stomachs were the remains of fish, crustaceans and insects.
Barfurth 1875 Ren, Denmark 20 in three stomachs of small insect debris

Miescher-Ruesch 1880
Ren whole river
     196 One Celtic remains of fish in the small kishechnke undigested "fly."
Zschokke 1891 Ren 129 One half-digested remains of plants and scud.

Heitz 1920
      170 in 14 fish plant remains chamber bags. Once you found a chink-Caddis.
Scheuring and Gaschott 1928 Ren 33 esophagus piece of wood

Zarnecki 1933
Wisla, Poland
        ? The male salmon had  - 6 roaches, in a dust, perch. The other two-density you, perch and 3 fish.
Kulmatycki 1933 Warta, Poland? The male at the time of spawning found roaches.

From the table, you can make at least two conclusions.
First - judging by the findings of undigested residues, not all salmon are denied opportunities to digest their prey in fresh water.
Second - in the esophagus and stomach get items that are difficult to be attributed to the stern.
  Chrzan F. (1957) believed that after spawning salmon returning to predatory-formed memories of life at once, but first sit down to a vegetarian diet. Perhaps because they burnup, PE parasites. Later J.Zool (1985) wrote about eating organic drifting, as the beginning of a return to normal diet. But he spoke of the non-migratory form of Atlantic salmon-ment.

Therefore, not all of which fell into the stomach can definitely be considered food, that is a consequence of eating salmon. Although it is unclear why the salmon ingest or der to reap the esophagus objects of aggression, inedible things. But sometimes, the very nature of the victims can talk about aggression as a cause ingest fish. Case has been described detected inside the trout (not salmon) more burbot, which in turn were filled with red caviar. Surely it was about protecting the nest, but the case can be extended to the behavior of salmon.

 Interest in surface facilities is difficult to explain. No complete data, which are a confirmed or denied food motives. Perhaps there are elements of aggression or curiosity fish. There is a possibility of error in the identification of salmo salar salmo trutta and in monitoring the gathering of food. But the facts of the salmon caught in the act are numerous. J.Jelenski believes that interest in the dry gunpoint hardly explain the desire to eat. He gives the example of when the fish attacked the cord in his contact with the water in the place where the image of the water "whiskers." But this is a love and dace and roach, which are difficult to suspect anything other than the desire to eat.
The first signs of a differentiated approach to the nature of the salmon can be found in the materials and Zarnecki Piatek (1954). On the material collected in the investigation of the Baltic salmon, they showed the existence of 2 large populations once belonged to the Vistula. "Winter" is a river in the winter and go to the rivers of the Tatra Mountains, the other "old" does not go so Leko-up and spawn in the lower tributaries. The authors pointed out the anatomical difference between the two populations and possible related differences in behavior. For example:

- Winter flock has almost twice as much abdominal fat than the years-it (5.6% by weight to 3%).
-Gallbladder all winter was full of fish, and the summer - is empty.
And females, and males of the winter sunset caught in the mouth of the river, had food in his stomach. In summer fish stomachs were empty. This observation is incorrect in this case, because the authors could not determine the time of finding the fish in the river. According to them, a lot of fat and likely to feed a common adaptive feature for fish, which have a long road.

An interesting interpretation of the facts, when food was found in the throat or esophagus de, not in the stomach. At first glance, this phenomenon can not be attributed to a direct proof of you feeding salmon in the river. The above mentioned authors cite cases regurgitation feed some salmon immediately after capture. These observations confirmed J.Jelenski, having found food in the pharynx and esophagus on an empty stomach.
There is an article by an unknown author (1904) of the Angling salmon are found in the stomachs of many minnows. Columbia River at the time was full of chalk-whose. From our point of view is interesting part of the greater power of the name of predatory fish in comparison with those whose stomachs were empty.
Maybe it makes sense not to allocate so strictly Salmo salar in the world other instant-riruyuschih salmon. Trends in behavior can be seen in the data, and Scott Cross-man (1973) pink salmon-eating insect larvae during the long journey up the river. Barnhart (1991) writes about the possibility of feeding steelhead in cases of prolonged stay in the river. In areas close to the mouth of their stomachs are empty or almost always empty. But in the upper parts of the rivers are full of fish can feed. Obra-schaetsya attention to the availability of feed is readily available and the lack of fishes, possibly more difficult objects for profit.
At the same time, J. Nyk, studying salmo trutta m.f. small rivers flowing into the Baltic Sea, clearly states that trout do not feed in the rivers to spawn. After spawning - yes!
Can I say so clearly on the example serebryanok caught just 3 km from the sea, I do not know. But the principle of different attitude to food fish spawning and return to the sea, may be used for salmon.
Briefly summarize:

1. Visual behaviors.

Indirect signs of power are confirmed:
-Attack on living objects on the surface and in the water.
-Attack flies imitating living objects.

2. Anatomical studies.

Indirect signs of power confirmed the presence of:
- In the throat and esophagus typical food organisms.
-The same objects in the stomach.
-Normal functional state of the gastrointestinal tract (filled with gall bladder and intestinal permeability).
Direct signs of power confirmed the presence of:
-Half-digested and undigested remains of living organisms stomach and intestines.

Given all of the objections and ambiguity "obvious" facts about nutrition salmon, we must recognize that:

A. Not all salmon feed in the rivers. Correct to speak of the possibility of supply.
B. Salmon can not feed intensively and regularly. Can be considered a fact, episodic, in some circumstances getting food into the stomach.

B. The presence of food in the stomach may indicate silver fish ancillary nature of power. In the case of the Kelts in the river feeding a reductive step in returning to the usual form.

Pity it was not possible to find out the details on the example of the behavior of salmon
single exponential population of salmon, one of the river. Studies include too few fish, small segments of time and limited areas of rivers. Remained of perfect clear motive, sometimes very intense, collecting salmon invertebrates from the surface and at the surface. But attention to the salmon Food items are not to be ignored. While in classical English literature generally of the opinion of the need for major fly fishing, since the beginning of the 20th century there is sufficient but data on greater efficiency of small flies. But the reasons for success are unclear, given the sporadic supply of salmon, if any inherent in this population. Elements of aggression in the behavior in the case of small flies probably play only a minor role.
 If you go further and talk about the practical application of conscious realization-particle simulations to catch, you can only make general conclusions. Relation to the potentially feed depends on the population of salmon, place it spawning fish deadlines approach. Matters and life stage of salmon in the river. We should also take into account the value of the river, the water level in it, the availability of food. Unfortunately, this infor-mation in a systematic way is not there. But the probability of its occurrence, hopefully, still exists.

Chavanga river, Top Camp site

     September. autumn run silver salmon. Pokosy camp site

 Here are photos of salmons which i land during grayling fishing using imitative flies.

June, Pokosy Camp, Chavanga river

Early August, Chavanga river, Top Camp site.

End of May, Chavanga Island Pool.

salmon fishing in Russia, pesca peninsola di Kola, peche au saumon Russie, lov lososu v Rusku, Pêche au saumon atlantique, fang von lachs in Russland, pesca del salmon in Russia,

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