Kyu Hee Son and Kyung Nam Han

1
The Effects of Marine Sand Mining on Biological
Communities in Gyeonggi Bay
Kyu Hee Son and Kyung Nam Han Department of
Oceanography, Inha University, Incheon 402-751,
Korea E-mail scuba89_at_nate.com
Abstract
The purpose of this study was to investigate
effects of rampant, large scale marine sand
mining on marine ecological community. For the
study, four stations along the coast were
selected and monitored in 1998, 2001 and 2006 by
grouping two stations into mining areas and the
other two into non-mining areas. It was found
that while sand mining was undertaken,
substrate-dwelling creatures like crustaceans
decreased by 40 to 60, varying with species,
population of crustaceans and seasons. In the
stations where sand mining stopped two years
back, a larger amount of marine biomass was found
in non-mining areas, compared with that of mining
areas. Since then, marine biomass increased
more rapidly in non-mining areas. While marine
species and biomass increased, the dominance of
several species became intensified in non-mining
areas and mining areas. It is therefore concluded
that the removal of submarine deposits and the
spread of floating particles have a significant
impact on crustaceans not only in areas where
mining took place but surrounding areas. Such
mining-associated effects also force fishes to
move to safe areas. Marine biomass increased in
mining areas and non-mining areas, but the speed
of ecological and environmental restoration
following sand mining and dominant species differ
between mining and non-mining areas.
Fig. 3. Variation of taxa A Number of species,
B Number of individuals, c Biomass at the
non-mining and mining area in spring
Table 2. Comparison of dominant species at the
non-mining and mining area in spring
Introduction
Korea consumes about 242,170,000? of aggregate
materials every year for engineering works and
apartment construction (The Ministry of
Construction and Transportation (MOCT, 2003).
About 225 million? were mined in Ongjin-Gun in
the Gyeonggi Bay over the last 21 years.
Ongjin-Gun serves as an important spawning and
nursery ground for temperate water species.
Therefore sand mining in Ongjin-Gun establishes a
contradiction against the protection of living
marine resources. As for effects of sand mining
on marine ecology, the earlier studies reported
damage caused by the absorption during mining
(Reine and Clarke, 1998 Dutta and Sookachoff,
1975 Arsenault, 1981), the spillover of the
slurry (MEC and Cheney, 1990) and changes in
marine habitation, reduced biomass and ecological
disturbance as a result of accumulation and
elimination of floating marine debris (Pagliai et
al., 1985 Bell and Devlin, 1983 Kenny and
Rees, 1994). The study aimed to investigate
changes in marine ecological community in sand
mining areas and non-mining areas around the
Dukjeok Island in the Gyeonggi Bay which is an
important spawning and nursery ground for
temperate water species Structural changes in
marine biomass in areas where mining was taking
place and areas in which mining discontinued were
compared.
Fig. 4. Variation of taxa A Number of species,
B Number of individuals, c Biomass at the
non-mining and mining area in summer
Table 3. Comparison of dominant species at the
non-mining and mining area in summer
Materials and Methods
Study Area
Collection and Analysis
Otter trawls were used to collect marine
samples, and each collection took 30 minutes at
speed of 3 ?/hr. To examine characteristics of
marine biomass, richness index (Margalef, 1958),
diversity index (Shannon and Weaver, 1949),
evenness index(Pielou, 1975) and dominance index
(Simpson, 1949) were calculated. Bray and
Curtis(1957) similarity index was used for
cluster analysis of similarity among stations in
each season. Plymouth Routines Multivariate
Ecological Research computer package (PRIMER) was
employed for analysis.
Fig. 1. A map showing the sampling sites of
Gyeonggi Bay(1998-2004). Non-sand mining area
represents St.1, 2 and Sand mining area mean St.
3, 4.
Results
Fig. 2. Variation of taxa A Number of species,
B Number of individuals, c Biomass at the
non-mining and mining area in winter
Fig. 6. Dendrogram for hierarchical clustering
using group-average linking of Bray-Curtis
similarities calculated on square-root
transformed individuals data.
Fig. 5. Change of number of species, number of
individiuals and biomass at the non-mining and
mining area in 2006.
Discussion
Sand mining has a significant impact on
crustaceans living not only in the coastal areas
where mining took place but also surrounding
areas. Fishes seem to avoid the influence of
sand mining as they are able to move rapidly.
Although biomass increased in non mining and
mining areas after sand mining ceased, but
ecological restoration varies with environmental
conditions.
Table 1. Comparison of dominant species at the
non-mining and mining area in winter
Reference
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