Pikeperch

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Pikeperch
Sander marinus.jpg

Pikeperch ( Sander marinus )

Systematics
Perch relatives (Percomorphaceae)
Order : Perch-like (Perciformes)
Subordination : Percoidei
Family : Real perch (Percidae)
Genre : Sander
Type : Pikeperch
Scientific name
Sander marinus
( G. Cuvier , 1828)

The sea ​​pikeperch ( Sander marinus ) is one of the 16 ancient species in the family Percidae or "real perch".

In 1811 in Zoographia Rossiae Asiaticae (Vol. 3: 243) from the Caucasus region, Peter Simon Pallas described a species of pikeperch (“ Perca Labrax ”) that prefers brackish water - in 1828 Cuvier gave it the now valid name Sander marinus . It does not differ significantly from the European zander : it has a slightly wider forehead, smaller scales and a darker color. But Cuvier adds that it is more valuable because it tastes much better. Due to superficial assessment of characteristics, they were later counted for a while in the otherwise North American genus (currently only a subgenus) Stizostedion (regardless of the fact that 1963-2006 all Sander were called "Stizostedion" ). As a result of overfishing , but also the general deterioration of the environment, its existence is now apparently threatened according to the IUCN , but - due to a lack of data - it is currently not possible to say more precisely (Bogutskaja 2008).

features

The sea pikeperch (Russian судак морський or судак буговець, i.e. bug pikeperch) was hardly longer than 60 cm, it reached a weight of 3 kg and an age of over 10 years. Its color is a gray-blue, which can darken so much that the usually well-demarcated (mostly nine) wide, dark bands are then hardly recognizable; the belly remains lighter in any case. In addition, there may be black spots or dots (and bands of them on the unpaired fins). Like the common pikeperch it has some catches on the jaws and palatine bones (palatina) (to pierce the prey, which often dies in a moment of "fright"). The Volga zander ( Sander volgensis ) and the "sucker" ( Canadian pikeperch , S. canadensis ) have no catches). The fin formula hardly distinguishes it either:

D1 XIV, D2 I / 22 (very closely following), A III / 11, P 12, VI / 5, C 17 (if you only count the divided rays; with pre-rays up to C ~ 30).

The number of scales on the lateral line (which extends to the caudal fin with three branches) is usually over 100. The forehead is significantly wider than the eye, and the trunk is barely flattened laterally. How many pyloric tubes the sea pikeperch has is unclear ( S. lucioperca usually has 7, S. volgensis 3 (like other Percidae), S. canadensis 3-9, S. marinus allegedly 4-6, but there are 1-3 of them often "reduced"). (Most) seven Branchiostegal rays have all pikeperch and all real perch in general . The head is not scaled (this feature was also often used to characterize species, but is variable in all).

distribution

This pikeperch only occurs in the Black and Caspian Seas, so it is a type of brackish water in which it also spawns. (It is therefore considered to be native to Azerbaijan , Bulgaria, Iran, Kazakhstan , Moldova , Romania, Russia, Turkmenistan and Ukraine . It does not appear in Turkey's fauna lists.) Here it prefers parts of the sea with lower salinity (around 1.5 ‰) and Depth (because of productivity), e.g. B. the stretch of coast between the Bug and Dnepr estuaries. The northern Sea of ​​Azov particularly suited him; It does not seem to have occurred in the Aral Sea , even when it had a low salinity (just over 1 ‰) in the 19th century. Although he goes into the lower reaches of the river, for example when following schools of fish, he never lingers in them any longer.

On the other hand, pikeperch living in the fringes of the Baltic Sea belong to Sander lucioperca , which only spawns in fresh water - even if doubts arise about this species distinction (already with Cuvier, then again with Ekström 1835. In such a case it is ultimately a matter of taste where one draws certain species boundaries). A genetic examination of the relationships was not possible due to a lack of marinus material (Faber and Stepien 1998).

Like many other fish species (e.g. Percarina ) it is a relic of the tertiary brackish Paratethys , so that it is now restricted to the northern part in the Black Sea, while it is more common in the Caspi Sea in the southern part. In spite of several transgressions he always found parts of low salinity in these waters . (At present it is of course no longer common anywhere, rather it is apparently “endangered”, perhaps already extinct outdoors - see below)

behavior

Like all pikeperch he is considered cautious in older literature, but "stupid", voracious and clumsy. The Tartars thought it was a perch from the Sea of Azov, blinded by the salt water (in North America the name “wall-eye” (for Sander vitreus ) has the same background - the gray light from the tapetum of the eyes was interpreted as a lens clouding). Its main diet consists of smaller schooling fish such as Gobiidae , Atherinidae , Percarina and the like. That he himself socially pursued, especially in his youth. In addition, of course, he picks up everything moving of a suitable size, e.g. B. the Mysida ("shrimp"). With increasing age, the sea zander, which is mainly active at twilight, becomes " benthic " (especially over rocks, scree and sand) and solitary.

In the spring, preferably at temperatures of 13 to 16 ° C, it reproduces in the limanes and near river mouths, where it has mostly spent the winter in a rather inactive manner. Outwardly, males and females hardly differ; Sexual maturity occurs around 45 cm in length (age 3+ or 4+). Old, large females can shed spawning masses of up to 126,000 eggs (3–4 mm in diameter). These are deposited in a pit that the male has prepared (they stick to pebbles and parts of plants) and guarded by him. The young hatch after two to two and a half weeks and initially still live on the yolk sac , then on plankton and insect larvae, but from 4 cm in length (because the scales develop) they start to chase small fish (e.g. Clupeonella ).

Danger

This fish has always been eagerly fished and was called "rare" as early as 1892, but it is hardly possible to assess earlier conditions, as the three Eastern European zander species, whose areas touch or overlap, cannot be clearly distinguished (Grimm 1883). In any case, it only came into distress after the Second World War thanks to industrialization: indirectly through changes in salinity and pollutants in the water, directly through overfishing and, after the enactment of protective provisions, also through "poaching" as well as through species alien to biocenoses , their influence is hardly predictable. In recent years it has rarely been caught (similar to mackerel or tuna in the Black Sea). But there is of course a great economic interest in promoting and maintaining it, for example through artificial breeding, keeping in stretch ponds or enclosures. It is said that seeds and fertilized eggs have also been frozen.

Remarks

  1. ↑ which is why it is sometimes claimed that there is only one D and that taxonomic speculations are wrongly linked to it.
  2. ↑ Since this information is only found once, it could be based on a mere generalization from the zander - for which it does not apply to all occurrences.

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