International Journal of Marine Science 2015, Vol.5, No.19, 1-10
7
threshold manner. This threshold obviously associated
with a qualitative leap in the
R. venosa
biochemical
processes providing quantitative predominance of
melanin (?) over the carotenoids. To confirm or refute
this version is necessary to conduct studies with
brown pigmented gonads Rapana and pray bivalves
Veneridae and Cardiidae also.
Probably males "melanin" line appeared singly before
but have not been marked since in various types of
studies to determine the sex is not necessary to extract
from the shell of the soft body entirely. The presence
of a large penis allows for sexual differentiation
without gonads, which are located in the upper part of
the shell spire and frequent breakages remain inside.
The fact that Turkish researchers (Saglam and
Duzgunes, 2014) identified the male gonad color as
“brownish” on 2004 samplings says that at least in the
shade of the gonads at the time was already marked
brown.
It is difficult to say how much change in the spectrum
color gonads is irreversible but it’s possible to say that
this phenomenon is fairly widespread and is not a
casual anomaly. Perhaps we are dealing with a steady
R.
venosa
evolutionary change having an ecological basis.
One explanation for the presence of abnormal colors
females mainly in the Blue bay is greater number of
examined specimens (260) than in the other our
regions combined (115 specimens). Variations in the
color of the gonads of females associated with their
imposex status (Mann et al., 2006, Micu et al., 2009).
In our Crimean samplings imposex females were not
found is not the result of inadequate sampling because
sex determination by the presence of the penis without
an accent on the gonads were held in more than 1,500
specimens of
R. venosa
. The lack of mention of
imposex females by Chuhchin V.D. who described in
detail the Rapana differences in the gonads and
studied of intersex phenomenon in other species of the
Black Sea gastropods (Chuhchin, 1961a, b, 1984)
means that the Rapana intersex individuals were
absent before of Sevastopol bay.
Considered to that the appearance of intersex
individuals is due to unfavorable environmental
conditions and, above all, the presence of various
types of pollutants. Observations of small-sized
gastropods genus Rissoa the free-water coast and in
the clear-water bays females with a penis are rare
whereas in polluted bays (Sevastopol bay) almost all
females
Rissoa splendida
Eichwald, 1830 have
underdeveloped penis. Strengthening masculinization
populations in polluted bays is happened when the
deterioration of living conditions in the Black Sea
Rissoa parva
(da Costa, 1778) and
R. membranacea
(J.
Adams, 1800)
also (Chuhchin, 1984).
Since the development of imposex in gastropods is
related to cumulative exposure to tributyltin (TBT)
and related chemical compounds (e.g. Smith 1971,
Gibbs et al. 1987, 1988, Bryan and Gibbs 1991,
Mensink et al. 1996, Oberdorster & McClellan-Green
2002, Stickle and Zhang 2003, all after Mann et al.,
2006), it is possible that female whelks are younger
than imposex female whelks and have thus been
exposed to environmental sources of TBT for less
time. TBT is a documented environmental pollutant in
the Chesapeake Bay (Mann et al., 2006).
The age range of the female population we
investigated was 2-11 years which almost corresponds
to the limits of life of more than 98%
R. venosa
. Thus
the age of the individuals is not a reason for the lack
imposex females in our samplings.
A special study on the presence and concentration of
TBT which is a main ingredient of marine antifouling
paints in the waters of the Crimea was not conducted.
However Sevastopol is a large navy, civilian cargo and
fishing port with a large number of small boats. Thus
the number of TBT-painted boats must be significant
and it can be assumed that the concentration of TBT in
the adjoining areas should be high.
The level of pollution lindane, DDT and DDD in
mollusks from the Romanian region Mamaia (Badiu et
al, 2008) corresponded to the average values of the
range of concentrations of the sum of α-, β- and
γ-hexachlorocyclohexane isomers, as well as pesticide
DDT in the Round bay. And the maximum values of
the above pollutants in mollusks of the Round bay
1.5- 2 times or more above (Malakhova et al, 2014).
Sampling locations for our research have sufficient
ecological differences to evaluate in general terms the
dependence of potential probability of occurrence
R.
venosa
intersex from pollution. The purest is Laspi
Bay (area 4) when the Blue Bay (2) and Cape
