1063-0740/02/2806- $27.00 © 2002
Russian Journal of Marine Biology, Vol. 28, No. 6, 2002, pp. 405–410.
Original Russian Text Copyright © 2002 by Biologiya Morya, Zvyagintsev, Moshchenko.
The distribution of fouling organisms on the hulls of
active ships has been a frequent subject of study [5, 8,
9, 15, 17, 22, 23, 26]. In this regard, the works of Rudy-
akova [22, 23] are the most interesting. She carefully
analyzed features of the settlement and distribution of
the main fouling organisms—barnacles, mussels, and
hydroids. Although her papers are descriptive and the
conclusions are deductive, being made “purely logi-
cally … without adducing concrete numerical data”
[cited after 22, p. 88], these papers are remarkable in
the originality of their judgments and hypotheses.
For example, this author, unlike other researchers,
explains the variation in settlement density and shell
size of barnacles along the hull of a ship from the bow
to the stern by the ﬂow pattern around the hull, and not
by the sequence and heterochronism of appearance of
barnacle larvae in plankton.
In our opinion, the hypothesis that the aggregative
distribution of fouling organisms is caused by the char-
acter of water ﬂow and by the development of zones of
small-scale turbulence at shear sites is the most valu-
able supposition by Rudyakova. The key points of this
hypothesis are the following. In case of turbulent ﬂow,
microeddies regularly penetrate into the viscous sub-
layer of the water boundary layer . This increases the
possibility of larvae approaching the substrate , and,
as a result, many animals settle on natural and anthro-
pogenic substrates near shear localities [13, 18, 23, 28],
i.e., in the sites where zones of small-scale turbulence
are well expressed. Microeddies promote not only the
approach of larvae to the substrate and its population,
but also the approach of objects that are included in the
rations of attached animals, many of which—for exam-
ple, barnacles and hydroids—are active predators. In
case of microvortex water movements, the probability
of capture of prey by many animals is known to rise [2,
6, 14, 19, 21] due to an increase in the frequency of
predator–prey encounters .
This hypothesis still has no instrumental conﬁrma-
tion, although it was used succesfully by one of the
authors for explaining the variability of the colony form
and distribution of hydroids (gen.
) and the presence of mass epibionts on
A part of factual material, on
which this work is based, was published elsewhere [11,
12]. In this study, we tried to prove the supposition of
Rudyakova, according to which the spotty distribution
of foulers is connected with the character of the water
ﬂow around the hull of the ship and with development
of zones of small-scale turbulence in shear locations.
MATERIALS AND METHODS.
The samples, collected during expeditions carried
out by the Institute of Marine Biology in 1976–1990,
were taken from ships by scuba according the scheme
presented in Fig. 1a; some other ships were examined
in dry docks. In the laboratory, plants and animals were
identiﬁed to speciﬁc rank and weighed on an electronic
balance with an accuracy of 0.001 g. Settlement density
was determined, if possible.
Because of the wide variety of ship exploitation (the
running regime, frequency of alternation between ﬂoat
and anchorage, duration and timing of navigation,
extent of the route, etc.), and the diversity of construc-
tions and protective coatings of hulls, it is rather difﬁ-
cult to get adequate data on the distribution of foulers.
In this respect, only the successful attempt of Mullineaux and
Butman  can be mentioned. They studied the dynamics of set-
tlement and the distribution of fouling organisms on plates of dif-
ferent thickness. They supposed laminar ﬂow in one case and tur-
bulent in another. However, they did not make any quantitative
The Role of Small-Scale Turbulence in the Distribution
of Macrofouling Organisms on the Hulls of Ocean-Going Ships
A.Yu. Zvyagintsev and A. V. Moshchenko
Institute of Marine Biology, Far East Division, Russian Academy of Sciences, Vladivostok, 690041 Russia
Received May 31, 2002
—Evidences in favor of the hypothesis of Rudyakova  are given, which states that the main reason
for the aggregative distribution of fouling organisms on the hulls of active long-voyage crafts (ocean-going
ships) is the uneven course of hydrodynamical process around the submerged part of the hull, particularly the
development of small-scale turbulence at sites of separation of the boundary layer (shear sites).
fouling organisms, distribution, small-scale turbulence, separation of boundary layer, ship hull