The Effects of Caging on the Colonization of Fouling Organisms in the Upper Bonny Estuary (original) (raw)
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Biofouling, 2003
Protection against biofouling is essential for efficient operation of boats and ships. Restrictions on the use of traditional, toxic antifouling coatings call for new less toxic methods. Future antifouling strategies will likely be based on more specific action against dominant foulers and will require more detailed information about spatial and temporal differences in fouling communities on artificial substrates. In this study, the recruitment and succession of fouling organisms was examined on artificial (PMMA) panels exposed to natural flow speeds on the Skagerrak coast (Sweden). The recruitment of foulers on static panels was then compared to fouling allowed to develop on boat hulls in surveys of new nontoxic coatings. The temporal and spatial variation in recruitment was examined on a monthly interval within the boating season, from May-September. Furthermore, the succession of the fouling community was examined during the same interval. A total of 12 sessile invertebrate species was recorded on the static panels with dominant foulers being the barnacle Balanus improvisus (July-September) and the mussel Mytilus edulis (June-August). The mean abundance during peak settlement on panels after 1 month's deployment was 370+134 individuals dm 72 for B. improvisus and 340+415 individuals dm 72 for M. edulis. The succession of foulers on the panels led to a dominance of M. edulis (maximum of 7470+2830 individuals dm 72 ) over B. improvisus (maximum of 2295+680 individuals dm 72 ). This was in contrast to the fouling development on boat hulls, examined after 4 months exposure in 3 successive years, where B. improvisus was the dominant species (mean abundance 222+104 and maximum 713+527 individuals dm 72 ). Some boats were covered to an extent of almost 100% by B. improvisus with only a few M. edulis (mean abundance 20+16). The biomass of fouling on boat hulls varied from average dry weights of 1.3+1 to 13+5 g dm 72 . These results show that extrapolation from static panels (common in evaluation of antifouling performance) to fouling on boat hulls may be problematic.
Journal of Experimental Marine Biology and Ecology, 1994
The effect of four substrata (concrete, plywood, fibreglass and aluminium) on the recruitment of species and development of an intertidal estuarine fouling assemblage was examined in Quibray Bay of Botany Bay, New South Wales, Australia. Many species, including the oyster Saccostrea commercialis (Iredale & Roughley) and the barnacles Hexaminius sp., Balanus amphitrite Darwin and Balanus variegatus Darwin, recruited in greater numbers on concrete or plywood surfaces than on fibreglass or aluminium. As a result, patterns of change in the number of species through time were dependent on the substratum. Multivariate analyses indicated that assemblages on different substrata were significantly different after 1 or 2 months of submersion, but became more similar after longer periods (up to 4-5 months). The reasons for this gradual conformity varied depending on the season of submersion and the composition of the species settling in a particular season. The results of this study indicated that the nature of the substratum can affect both initial colonisation of particular species and the development of the assemblage over time. Because the effect of substratum varies with the period of submersion, comparisons of various studies on fouling assemblages using different natural and artificial substrata and for varying lengths of time are likely to be very difficult.
Fouling assemblages associated with estuarine artificial reefs in new South Wales, Australia
Brazilian Journal of Oceanography, 2011
Previous studies examining the dynamics of succession on artificial reefs have predominantly focussed on fish communities and largely ignored the role of fouling assemblages in explaining the patterns of community structure associated with artificial reefs. The objective of this study was to record the development of epibiotic assemblages on three "design specific" (Reef Ball ® ) estuarine artificial reefs systems located in Lake Macquarie, Botany Bay and St Georges Basin in New South Wales, Australia. Recruitment to the artificial reefs was relatively rapid with the majority of taxa identified over the two-year study period observed within the first year post-deployment. The artificial reefs in Lake Macquarie and St Georges Basin were characterised by low diversity with four and nine taxa recorded respectively in contrast to the sixteen taxa observed on the Botany Bay reefs. Results indicated no significant differences in percentage cover of taxa among reefs in either St Georges Basin or Lake Macquarie. In contrast, comparisons between individual Botany Bay reefs identified significant differences in the percentage cover of species between artificial reefs. Analysis of assemblage structure with reef age indicated discrete patterns among estuaries with an overall reduction in the percentage cover of filamentous turfing algae (FTA) identified for all reef systems with an increase in reef age. Variations in environmental and physical conditions (turbidity, water flow, wave action and proximity to naturally occurring reef) may have contributed to the observed differences in fouling assemblages between estuaries and between artificial reefs within Botany Bay.
Aquaculture, 2007
Growth of fouling organisms on suspended fish cages is an impediment to aquaculture projects in coastal waters around the world. The present study characterized ecological succession of fouling communities on the netting of fish cages at an open ocean aquaculture site 10 km east of New Hampshire, USA in the western Gulf of Maine. Ecological succession can be defined as the process by which a community moves from a simple level of organization to a more complex community. Routine cleaning of the cages causes loss of organisms and initiation of ecological succession. Experimental panels of nylon net material were deployed at different times of the year and for different durations from September 2002 to September 2003 (eleven sets of 1-month panels, four sets of 3-month panels, two sets of 6-month panels, and one set of 1-year panels), with four replicates of each deployment. Panels were randomly arranged on a grid that was attached to a fish cage at a water depth of ∼15 m. There were substantial and significant differences in density and biomass of the total communities of most successional sequences when comparing panels deployed during May-September to those deployed during the cooler months, October-April. However, the blue mussel, Mytilus edulis, dominated in density and biomass in almost every sequence, regardless of time of initiation or duration. Other species that occurred in high numbers and/or biomass were the amphipods Caprella sp. and Jassa marmorata, the molluscs Hiatella arctica and Anomia sp., the seastar Asterias vulgaris, and the anemone Metridium senile. Juveniles and adults of some species were also present in some early (1-month) successional sequences, indicating that migration may be an important process in community development. Some of the dominant species listed above were present in all successional stages (early, intermediate and late), differing only in relative abundances in the community. The consistent dominance of M. edulis, and other differences in successional patterns compared to what has been typically observed for epifaunal communities in the region, were hypothesized to be the result of a combination of factors: a lack of predators such as seastars and fish that typically consume mussels in natural communities, excessive predation by nudibranchs on those species (e.g., Tubularia sp.) normally abundant in early successional stages, year-round availability of mussel larvae, and cage cleaning protocols that do not remove all the organisms present. The introduction of predatory fishes or seastars into or onto the cages might provide some amount of control on the growth of fouling organisms.
Experimental studies on Macro fouling communities on net panels at marine cage farm of Karwar, India
2017
A study was undertaken on the fouling pattern, monthly settlement and species dominance at marine cage culture during the year 2014-2015. The net panels deployed at three different depths during December 2014 and the study was carried out for seven months. The study revealed wide variations in colonization of the bio-foulers, the density varied between 2-260/cm2. The overall density was found to be more in bottom panels (6mt) compared to the top (1mt) and middle panels (3mt). The overall dominant species were hydroids and barnacles throughout the culture period. In the top panels, hydroids were dominant (91.67%) during December, followed by barnacles and amphipods. Additionally, complete dominance of barnacles was observed in the middle panel during May. Barnacles were found dominant (93.75%) on the bottom panels during March, followed by hydroids and crabs. The study underscored that barnacles formed a major contribution of the fouling organisms throughout the culture period. Signi...
Effects of patch size on colonisation in estuaries: revisiting the species-area relationship
Oecologia, 1999
The eects of patch size on the colonisation and succession of intertidal invertebrates and algae were investigated in an estuary near Sydney, New South Wales, Australia. The speci®c aim was to test explicitly for the presence of a species-area relationship, and examine whether this could be explained by the random placement hypothesis (i.e. that the number of species per unit area was the same on patches of dierent sizes). In addition, I tested the extent to which dierences in numbers of species re¯ected dierences in the composition of assemblages. Wooden panels of three dierent sizes (10´10 cm, 20´20 cm and 40´40 cm) were placed in the ®eld on intertidal oyster leases in each of two dierent experimental trials: spring (October 1994) and summer (January 1995). Independent replicate measures of the number of colonising species on panels were obtained after dierent periods of time, up to 25 months. I also obtained measures of abundance of individual species and composition of assemblages on panels of dierent sizes. This allowed speci®c tests of the hypothesis that the size of the patch being colonised is important in structuring these assemblages. The strength of the species-area relationship increased through time on panels submersed in October, but the trend was reversed for panels submersed in January. There was a signi®cant interaction between factors of patch size and time of submersion for multivariate measures of dierences in composition among replicates. The random placement hypothesis was supported in certain situations, but not in others. When rejected, it was for different reasons on panels submersed in the two dierent trials. Panels initiated in October tended to have proportionally greater numbers of species per unit area on larger panels, while the panels initiated in January tended to have more species per unit area on smaller panels. There was an identi®able relationship between dierences in numbers of species and dierences in species composition for panels submersed in October. This was not true, however, for panels submersed in January, where the species-area relationship did not hold after longer periods. The succession of organisms through time was, overall, more important in structuring the assemblages than was the size of the patch being colonised. The species-area relationship should not necessarily be regarded as a truism ± it did not always hold in this system. The initial timing of experiments with respect to recruitment and succession in¯uenced the results.
The influence of estuarine water quality on cover of barnacles and Enteromorpha spp
Environmental Monitoring and Assessment, 2011
The influence of ambient water quality on the settlement of barnacles and the green alga Enteromorpha spp. 20 to an artificial substratum in the estuaries of Sydney, Australia, was investigated to test the efficacy of both groups of 21 organisms as indicators of changes in water quality due to urban stormwater runoff and/or sewage overflows. Wooden 22 settlement panels were immersed for four months on 17 occasions between 1996 and 2005 at 11 locations known to 23 vary in water quality parameters (conductivity, total uncombined ammonia, oxidised nitrogen, total nitrogen, filterable 24 phosphorus, total phosphorus, faecal coliforms and chlorophyll-a) and ambient meteorological conditions (total rainfall, 25 maximum rainfall). Water quality data were collected during the time that the settlement panels were deployed. Cover 26 of barnacles was highly variable among locations (range 1.2 -55.2%). Hierarchical partitioning found that chlorophyll-27 a, total phosphorus and total nitrogen had significant independent positive effects on barnacle cover. Together, these 28 variables explained 26% of the variation in barnacle cover. Mean cover of Enteromorpha spp., however, did not vary 29 significantly among locations suggesting that other potentially more important factors are influencing its settlement and 30 growth. The results of this study suggest that barnacle cover is likely to be a useful indicator of some components of 31 water quality.
Brazilian Journal of Oceanography, 2008
In marine fouling communities, free space is one of the key limiting resources for settlement of new organisms. In this way, removing biomass through physical disturbances would play an important role in the structure and dynamics of these communities. The disturbance size seems to be a characteristic that influences recolonization patterns, thus affecting species diversity. The aim of this study was to analyze the effects of growing disturbance areas on fouling communities. Fouling panels were allowed to develop for 6 mo. at Guanabara Bay (22°52'S, 043°08'W) prior to a single application of randomly positioned, circular physical disturbances of growing areas (7 levels, from 0 to 75% removed cover, 10 replicates per treatment). Samples were taken fortnightly after the disturbance event, so as to follow the development patterns of the community afterward. At the first sampling the diversity showed maximum indices in communities to which intermediary disturbance levels were applied. However, this profile changed later to a diversity peak in communities with higher disturbance levels. It also showed a continuous increase in richness and diversity through time until the 7th sample (110 days after the disturbance event), with subsequent decrease. Such patterns seem to corroborate the Intermediate Disturbance Hypothesis, despite the drastic profile change with time, revealing that disturbance is indeed an important factor structuring hard bottom communities at Guanabara Bay, and highlighting the importance of longer term studies of disturbance impacts in marine communities.