THE BLACK SEA
ICHTHYOFAUNA: STRUCTURE,
CHANGES, PROBLEMS
A. Boltachev, E. Karpova
Institute of Biology of the
Southern Seas, NAS of Ukraine

Black Sea
Considerable isolation of
the Black Sea from the
World Ocean, specificity of
the habitat environment
hydrologo-hydrochemical
conditions, heavy geological
past and contemporary
anthropogenic
pressure
affected fundamentally the
processes in the unique
ichthyofauna formation and
changing.
Black Sea
According to recent data, obtained as a result of successful
cooperation of expert-ichthyologists of the BSC from all the
Black Sea countries the Black Sea ichthyofauna numbers 234
fish species and subspecies, which are attributed to 68 families.
We would like to express our deep gratitude to Maria Yankova,
Violeta Velikova, Valeria Abaza and all colleagues for
cooperation in creating the ”Black Sea Fish Check-List”.
Ichthyofauna
Idea of the genesis of the Black Sea ichthyofauna was first developed
by K. F. Kessler (1877), his basic assumption was the presence of two
components of groups:
1) ancient autochthonous species
originated from a diverse and
numerous relict fish that had
no
similar forms in other marine basins
2) allochthonous species, whose
formation is directly related to the last
joint of the Black Sea with the
Mediterranean and active processes
of the fish mass immigrations from
the Mediterranean Sea.
Mesogobius barachocephalus
Aidablennius sphinx
In addition to these two groups, V.K. Sovinsky (1904) has allocated the
third ones - the "new autochthonous", which included a
fully naturalized Mediterranean immigrants in to the Black Sea and formed
a species (Syngnathus schmidti) or subspecies (Trachurus mediterraneus
ponticus, Merlangius merlangus euxinus, Belone belone euxini), totally about 60 species and
Syngnathus schmidti
subspecies.
Ichthyofauna
This is an important moment of the contemporary Black Sea ichthyofauna
formation.
At the present time, the fact of taxonomical isolation of the Black Sea
subspecies is not adopted by the number of ichthyologists and they attribute
them to those previously excepted Atlantic-Mediterranean Sea species.
The other ichthyologists consider that the majority of the Black Sea fish
subspecies are valid species.
We think that it is necessary to conduct taxonomic revision of the Black Sea
ichthyofauna, using morphometric and genetic methods. Working out,
implementation and financing of such international program under the aegis
of the Black Sea Commission are quite actual.
These investigations are not only of theoretic but of practical importance as well
for preservation and rational usage of separate Black Sea fish species.
Ichthyofauna
Ichthyofauna of the Black Sea includes fishes,
very
different
by
their
genesis,
ecological and faunistic complexes; they should
be united in 4 main groups: marine – 146 species
(62,4%), diadromous – 17 (7,3%), brackish water
ponto-caspian endemics – 20 (8,5%) and fresh
water, including semi-diadromous – 51 (21,8%)
fishes.
62.4%
21.8%
8.5%
-
7.3%
marine
diadromous
brackishwater ponto-caspian endemics
freshwater (including semi-diadromous)
Marine fishes
Species, inhabiting the Mediterranean-Atlantic basin mainly (142 species) are
prevailing among the marine fishes, but some of them are widespread more in the
World Ocean. Two subgroups can be isolated by their origin – thermophilic
tropical, subtropical and psychrophilic boreal Atlantic species.
Over 90% of Mediterranean immigrants are thermophilic
tropical and subtropical species.
0
20
40
60
AtlanticMediterranean
80
100
120
140
160
Boreal Atlantic
Indo-Pacific
Less than 10% are cold-boreal-Atlantic species. According
to well-known ichthyologist T.S. Russ occupancy by boreal
species occurred in the early Holocene, thermophilic much later - less than 8 thousand years ago. On this
basis he has allocated a group of "Boreal-Atlantic relict
fish." This hypothesis has been subjected to sharp criticism
from V.A. Vodyanitsky, who believed that the species
included in it are the Mediterranean immigrants of boreal
origin, and
invasion
by
psychrophilic – and
thermophilic fish happened at the same time and use of
the term "Boreal-Atlantic relicts" is not correct. We
support this view of V.A. Vodyanitsky.
Subgroup of marine fishes from distant areas of the World
Ocean is new to the Black Sea.
Marine fishes
The appearance of this last subgroup of marine fishes in the Black Sea is
connected with the anthropogenic activities (4 species).
Liza haematocheila, possibly being
naturalized in the Azov-Black Sea basin
completely
Tridentiger trigonocephalus, invaded the Sevastopol bay
as a result of occasional discharge from aquarium or
with ballast waters
Indo-Pacific red barracuda (Sphyraena pinguis) moved
in through the Suez Canal in the eastern Mediterranean
(Lesseps migrant), which to date has achieved a
high number, and could easily penetrate through the straits
into the Black Sea, down to the south-west coast of the
Crimea. Extension of its migration to the Black Sea during
the warm season is possible.
The appearance in the Balaklava Bay of exotic Indo-Pacific coral
fish Heniochus acuminatus obviously is associated with ballast
water and is accidental.
Brackish water ponto-caspian endemic fishes
Group of brackish water ponto-caspian endemics, which
includes representatives of 7 autochthonic genera from the
family Gobiidae and some other (for example, Clupeonella
cultriventris, Pungitius platygaster and Percarina demidoffi)
is unique. According to the opinion of some researchers,
formation of the brackish water group as well as of
diadromous herrings of the genus Alosa from the initially
marine species occurred in Miocene as far as Sarmatic Sea
(existed from 7(5) to 3 (2) mln. years ago) was becoming
more and more freshwater and they should be called
Sarmatian relicts. According to another version, the
previously mentioned ancient autochthonic complex,
including diadromous Acipenseridae appeared later – in
Pliocene, when 2 (1,5) – 1 mln. years ago, at the place of
the salt Maeotic Sea appeared almost fresh water Pontian
Lake-Sea, and because of it, they are called Pontian or
Ponto-Caspian relicts.
Knipowitschia caucasica
Pungitius platygaster
Bentophiloides brauneri
Diadromous fishes
Anguilla anguilla
Alosa immaculata
Sander marinus
Populations of the most diadromous species (Acipenseridae, Salmonidae) are in the
critical state, which is connected with their over-catch, spawning places destroy in rivers
and damming the ways of spawning migrations.
Acipenser
gueldenshtadtii
Acipenser stellatus
Salmo labrax
Huso huso
Freshwater fishes
The fresh water fish group, by the opinion of the most
investigators, beginning with P.S.Pallas, is one of basic
components of the Black Sea ichthyofauna. But there is an
opposite opinion, according to which they must be excluded from
the general list of the Black Sea ichthyofauna. We think, it is not
correct, because fresh water fish can be noticed more or less
constantly in the estuary and before-estuary zones and the
region of the near - Kerch strait.
Alburnus alburnus and Scardinius erythrophthalmus - common inhabitants of the Gulf Karkinitsky
in the Black Sea
Gambusia holbrooki in the estuary in
the Bay of Sevastopol
Carassius gibelio in large
quantities
are
in estuaries, lagoons,
north-western
part
of
Black Sea, off the coast of
eastern Crimea, and other
parts.
Semi-diadromous Abramis brama and Stizostedion lucioperca present in the catches of
fishermen
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Conclusion

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What changes of the Black Sea
ichthyofauna structure can be predicted in
the future?
Increase of the marine fish share at the
expense of the continuing process of
Mediterranization, occasional invasion of
the small ecologically plastic species with
the ballast waters or inhabiting among
fouling hydrobionts on the underwater
parts of the vessels is mostly probable.
Decrease of the species diversity of the
valuable
diadromous
and
semidiadromous fish occurs as a result of the
considerable worsening of the habitat
conditions in the rivers.
Besides, traditional migrations of the
pelagic and large species firstly through
Bosporus at the present time is
problematic, which is connected with the
very active Turkish fishery, great
acoustical pressure as a result of intensive
navigation and high degree of the strait
waters contamination by industrialdomestic discharge.
Thank you for
attention!