Fish and Fisheries Research: Reports and Scientific News 
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Subject: Two populations of Coregonus albula (Linnaeus, 1758) in Lake Stechlin
  (Germany, Brandenburg)
  
   Authors: K. Anwand, G. Staaks and M. Valentin
   Source: IGB Berlin, Germany
   Date: 03.09.1996
   Head of Reseach Group: Prof. Dr. Karl Anwand
   Electronic mail: oki@igb-berlin.de (Dr. Georg Staaks)
   Telefax: +49 (0)30 64 181 600
   Telephone: +49 (0)30 64 181 612
   Postal address: Institute of Freshwater Ecology and Inland Fisheries
   Department Biology and Ecology of Fishes, Mueggelseedamm 310, D -
   12587 Berlin, Germany
   
  Species identification and Stock identity
  
   Scientific name of species: Coregonus albula Linnaeus
   Local name: Kleine Maräne, vendace
   Geographical area: Germany, Brandenburg, Lake Stechlin
   
  Source of additional information
  
   In press: K. Anwand, G. Staaks, M. Valentin (1996)
   Zwei unterschiedliche Formen con coregonus albula L. ( Teleostei;
   Coregonidae ) im nordbrandenburgischen Stechlinsee (Deutschland). Z.
   Fischkunde
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  Abstract:
  
   In Lake Stechlin (Brandenburg, Germany) two populations of vendace (
   Coregonus albula L.) were found. They differ statistically significant
   in several morphological characteristics. Furthermore they spawn at
   different times, select other habitats in the lake and show different
   growth rates.Both varieties, the nominal and the deepwater type, live
   in harmonious coexistence without producing bastards. The deepwater
   variety differs also from Coregonus albula lucinensis , which was
   found and described by Thienemann (1933) and Waterstraat (1990) in
   Lake Breiter and Schmaler Luzin (Mecklenburg, Germany). Both deepwater
   varieties seem to be relics from the early postglacial period, which
   survived because of their hydrogeographic isolation. The Lake Stechlin
   is the second place in Germany and the whole southern Baltic region
   where this rare and nearly extinct vendace was found.
   
    Keywords:
    
   Coregonus albula , Coregonus albula lucinensis , morphologic
   characteristics, relic species, endangered species, Lake Stechlin
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   In 1933 Thienemann published the very first description of a deep
   water variety of Coregonus albula L. from the waters around Feldberg,
   Lake Breiter Luzin, Lake Schmaler Luzin and Lake Carwitz in
   Mecklenburg- Vorpommern. He described this to be a separate species
   Coregonus albula lucinensis . This species differed from the common
   vendace which is widespread in North Germany and the whole baltic
   region in certain morphological characteristics: a flat head, a
   different shape of eyes, shorter gill rakers at the first branchial
   arcus. Furthermore Coregonus albula lucinensis showed an other growing
   speed, and kind of nutrition (benthic feeder). It mainly lives in the
   greater depths of the hypolimnic region below 20 m, which led to its
   characterization as a "deepwater variety" of Coregonus albula .
   Thienemann (1933) postulated this population to be a relic community
   of the primitive vendace species from the cold early postglacial
   period, which survived because of the hydrogeographic isolation from
   the surrounding vendace-lakes and the hitherto remained oligothrophic
   character of the Feldberger waters. This unique species had not yet
   been discovered in other german lakes. Waterstraat (1990) proved its
   recent existence in Lake Breiter Luzin and compared the both
   populations of the common and deep water variety, as had Thienemann
   done years before. 30 years after Thienemann, Bauch (1963) remarked,
   that along with the common vendace a deep water variety of vendace
   should also exist in Lake Stechlin (Brandenburg), but he did not
   deliver exact scientific data. Because this variety of vendace was not
   found in the catches of professional fisherman, nothing was known
   about the its further existence and biology. It seemed to be distinct.
   
   During our ichthyofaunistic research we surprisingly dicovered two
   different populations of Coregonus albula to exist in Lake Stechlin
   (1) . As a precise analysis showed, they are dissimilar in several
   morphological, biological and ecological characteristics. They will be
   labeled the nominal and deepwater variety, until further
   investigations allow an exact taxonomic classification. Additionally
   the deep water varieties of vendace from Lake Stechlin and Lake
   Breiter Luzin differ from one another.
   
   The most important differences between both varieties of vendace from
   Lake Stechlin are:
   
    1. Ten morphologic parameters, which formerly proved to be especially
       useful for the differentiating of vendace species were measured.
       Four of them showed statistically significant differences between
       the nominal and deepwater variety of Coregonus albula .(table 1)
       
       CAPTION: Table 1. Comparison of the nominal and the deepwater
       varieties of vendace (Coregonus albula L.) from Lake Stechlin
       
       morphological characteristics nominal type deepwater variety
       mean s n mean s n t-value
       number of scales
       in the lateral line 82.30 1.18 86 80.65 1.64 190 8.40**
       number of
       vertebrae 54.33 1.21 90 53.11 1.26 196 7.86**
       number of soft rays
       of the anal fin 11.09 0.78 88 10.90 0.78 191 1.89
       number of gill rakers at
       the first branchial arcus 43.44 1.26 62 43.56 1.14 191 0.72
       relative length of
       gill rakers [%] 3.22 0.21 62 3.47 0.46 193 4.02**
       hight to width
       of eyes [%] 92.78 6.13 90 94.76 9.31 205 1.89
       length of head to
       total length [%] 20.96 1.04 90 21.93 1.58 205 5.32**
       width of head to
       length of head [%] 31.39 3.39 90 30.86 3.93 205 1.17
       distance of ventral fin
       and anus [cm] at
       Lt < = 18 and = > 21cm 1.47 0.25 59 1.42 0.32 36 0.84
       s = standard deviation; n = number of fish
       ** significant difference at the 0,001 level
       These were:
          + number of scales along the lateral line,
          + number of vertebrae,
          + relative length of gill rakers at the first branchial arcus,
          + relative length of head.
       Despite these differences both varieties are very similar in
       appearance and could not be easily determined by eye.
    2. An important difference exists at spawning time and in the cycle
       of maturation between the both varieties of vendace. While the
       nominal type normally spawns at the beginning of December, the
       deepwater type reproduces, according to the latest observations,
       toward the end of April until the beginning of May. So we must
       consider the latter to be a springtime spawner like the
       Scandinavian species Coregonus tryboni (Svärdson, 1957, 1979).
       This dissimilar behaviour prevents the development of bastards
       between both varieties and enables their harmonious coexistence.
       Nothing is known about the spawning grounds of the deepwater
       variety until now.
    3. Both populations occupy different habitats of Lake Stechlin . This
       was proved through catches with gillnets at different depths, in
       which we found the nominal type to live most often above 20 to 25
       m while the deepwater variety settles at greater depths. Because
       of the oligothrophic character of the lake, good conditions for
       the existence of vendace are found in these depths throughout the
       year.
    4. An obvious difference also exists in the growth of both varieties.
       The growth of the nominal type refers to the average growth of
       Coregonus albula in other lakes of northern Germany (Bauch, 1963,
       Müller, 1958, 1966). The growth of the deepwater type is
       comparatively slower (table 2). As short living species, both
       varieties reach only an age of 5 to 6 years.
       
       CAPTION: Table 2.Growth of the nominal and the deepwater varieties
       of vendace (Coregonus albula L.) from Lake Stechlin
       
       Age
       [years] nominal type deepwater variety
       mean Lt
       [cm] mean weight
       [g] mean Lt
       [cm] mean weight
       [g]
       1 11.0 7.5 8.2 4.7
       2 18.5 44.0 12.2 11.8
       3 20.1 61.3 14.4 18.8
       4 21.4 70.5 16.4 29.6
       5 23 95.2 20.4 49.3
       
   To enlarge our existing knowledge of both varieties of vendace in Lake
   Stechlin , further research on these populations is planned. This will
   also include electrophoretic methods of population determination.
   
   Besides the differences between nominal and deepwater types of Lake
   Stechlin also the two deepwater varieties of Lake Stechlin and Lake
   Breiter Luzin differ from one another. They show small dissimilarities
   in morphological parameters, growth and nutrition. Despite this both
   varieties seem to be relics of the cold postglacial period. They
   maintained their former body shapes and were able to survive in both
   of these waters. Furthermore they seem to be related to the
   Scandinavian springtime spawning vendace species. As ichthyofaunistic
   rare species with only these two known habitats in Germany and the
   southern Baltic region, they must be regarded as a greatly endangered
   species which demands special attention and protection.
   
  References:
  
   Bauch, G. (1963).
   Die einheimischen Süßwasserfische. Neumann-Verlag. Radebeul und Berlin
   
   Casper, S. J. (ed.) (1985).
   Lake Stechlin - A temperate oligotrophic lake. Monogr. Biol. 58.
   Dortrecht, Bosten, Lancaster
   
   Müller, H. (1958).
   Die Einbürgerung der Kleinen Maräne in tiefe Bleiseen. Dtsch.
   Fischerei-Ztg. 5: 292-301
   
   Müller, H. (1966).
   Die für die Kleine Maräne (Coregonus albula L.) geeigneten Gewässer
   der DDR. Dtsch. Fischerei-Ztg. 13: 362-372
   
   Svärdson, G. (1957).
   The coregonid problem. VI. The palaearctic species and their
   intergrades. Rep. Inst. Freshwater Res. Drottingholm 38: 267-356
   
   Svärdson, G. (1959).
   Speciations of coreginid fishes. Rep. Inst. Freshwater Res.
   Drottingholm 57: 1-57
   
   Thienemann, A. (1933).
   Coregonus albula lucinensis , eine Tiefenform der Kleinen Maräne aus
   einem norddeutschen See. Zugleich ein Beitrag zur Rassenbildung bei
   Coregonus albula L. Z. Morph. Ökol. Tiere 27: 654-683
   
   Waterstraat, A. (1990).
   Ökologische Untersuchungen an Populationen der Kleinen Maräne
   (Coregonus albula L.) im Breiten Luzin (Bezirk Neubrandenburg)
   Fortschr. Fischereiwiss. 9: 93-104
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