Abundance Of Benthic Macrofauna Research Articles

Benthic macrofauna of Spartina alterniflora marshes and nearby unvegetated tidal flats of Paranagua Bay (SE Brazil)

The composition and distribution of benthic macro fauna in Spartirui alterniflora marshes and nearby unvegetated tidal flats of Paranagua Bay (SE, Brazil) were investigated. Samples were taken along a salinity and physical gradient, from the inner to the outer bay. The bay was divided into sectors according to its physico-chemical and faunal characteristics. Salt marshes were affected by the gradient, with the tallest formations developing in the mesohaline sector and the lowest ones in the euhaline sector. Macrobenthic associations were also affected, with the mesohaline sector presenting a low species richness of predominantly epibenthie forms. In this sector, the composition and abundance of benthic macrofauna of the salt marshes and unvegetated flats were distinct. Species richness of the polyhaline sector, particularly of the infaunal taxa, was higher than that of the mesohaline sector. Differences between the fauna of marshes and flats became increasingly evident towards the euhaline, high energy sector, characterized by the highest species richness along the bay. Benthic associations from marshes and unvegetated flats were clearly structured by the salinity and physical gradient. Although salt marsh and flats present a relative homogeneity in physico-chemical parameters, the composition and abundance of associated benthic fauna can vary widely, particularly in poly- and euhaline sectors.

Manipulating habitat complexity to understand its influence on benthic macrofauna

Generally, environments with a great habitat complexity (HC) can support a great number of species and large abundances of organisms. However, the mechanisms behind this effect are not entirely clear and some studies did not observe positive effects of complexity on diversity and abundance of biological assemblages. Here, HC was considered as an integrative perspective, specifically as different characteristics of physical structure and; it was tested whether abundance and diversity of macrobenthic assemblages of soft bottom are influenced by variation of two characteristics of habitat complexity, the number and evenness of sediment fractions. The hypothesized positive relationships between HC and richness, Shannon-Wiener diversity index and abundance of benthic macrofauna were not observed. The different response variables (richness, Shannon-Wiener, abundance) which consider different dimensions of biodiversity, can show distinct results when the same habitat is compared. For both structural characteristics of the sediment, a large amount of specimens of Bispira sp. (Polychaeta: Sabellidae) and Terebellides sp. (Polychaeta: Trichobranchidae) were observed in the most complex treatments. These taxa were favored by the presence of gravels where their larvae, likely originated from adult populations at nearby habitats, can settle. The multidimensional structure of the benthic macrofauna was significantly influenced by habitat complexity; and considering high taxonomical and functional diversity, multivariate analyses were more appropriated to investigate such complex effects. In this context, it is clear that careful thought must be given to choose appropriated habitat complexity characteristics and biological measurements. Therefore, studies addressing different combinations of structural characteristics of habitat and mechanisms behind the effects on biological communities are still of great need in ecological science.

Determinacion y evaluacion de los componentes presentes en las pinturas anti incrustantes utilizadas en la acuicultura y sus posibles efectos en sedimentos marinos del sur de Chile

Sediment samples were taken in three areas related to the use of antifouling paints in salmon farming in southern Chile, in order to detect changes in the abundance and diversity of benthic macrofauna due to the accumulation of metals such as Cu and Zn in sediments. The results show that if there especially Cu accumulation in sediments adjacent to cages each crop, but there were no significant changes in the composition or abundance of benthic macrofauna that accompanies these farms, even when concentrations Cu exceeded 800 µg g -1 in sediments.

Biodiversity and seasonal variation of benthic macrofauna in Minicoy Island, Lakshadweep, India

From the Indian coast only limited data are available on the benthic fauna of the seagrass communities. In this study, seasonal variation in the distribution of macrobenthos and influence of environmental parameters was explored at four seagrass beds and two mangrove stations along the Minicoy Island, Lakshadweep, India, from September 1999 to August 2001. A total of 160 macrobenthic species from eight major groups represented the macrofauna of the Minicoy Island. Of the identified taxa, molluscs 70 (gastropods 41.46%, bivalves 7.5%), polychaetes 27 (16.88%), crustaceans 30 (18.75%), echinoderms 11 (6.88%) and remaining others. Average seasonal abundance of benthic macrofauna ranged from 219 to 711 ind./m2, species diversity varied from 1.45 to 3.64 bits per individual, species richness index ranged from 4.01 to 26.17, evenness 0.69 to 1.66. In general, the higher abundance and species diversity was noticed in southern seagrass stations and northern seagrass stations, but in the mangrove stations comparatively low species diversity was observed. Three-way analysis of variance indicated that all communities resulted as being significantly different between seagrass and mangrove station, mainly when the seasonal interaction was considered. Multivariate analyses were employed to help define benthic characteristic and the relationship between environmental parameters at the six monitoring stations. Results of cluster analyses and multidimensional scale plot suggest that for mangrove region, different physiographic provinces, lower salinity, dissolved oxygen and sediment biotic structure have a higher influence on the species composition and diversity than other oceanographic conditions.

Seabed habitat mapping employing single and multi-beam backscatter data: A case study from the western continental shelf of India

Acoustic backscatter from multi-beam echo-sounder (MBES) and dual-frequency single-beam echo-sounding systems (SBES) operable at 95kHz and 33/210kHz, respectively, were used to study the distribution of sediment texture and benthic macro-fauna along the central part of the western continental shelf of India (off Goa). To characterize the continental shelf seafloor, single-beam and multi-beam backscatter signals were acquired along with grab sediment samples. The relationships between processed acoustic backscatter strength, grain size, and benthic macro-fauna abundance were demonstrated employing clustering technique (PCA) and Geographic Information System (GIS) based mapping. The clustering analysis delineated that the backscatter values at three frequencies are strongly correlated with both substrate type and faunal functional groups. The preferences of deposit feeders (soft body benthic macro-fauna) for the fine-sediment regions and filter feeders (hard body benthic macro-fauna) for coarse sediment regions were linked to the variations in sediment granulometry as well as backscatter strengths in the study area. This study further demonstrates the utility of high frequency backscatter data employing echo-sounding systems towards the interpretation of seafloor sediments and benthic habitat characteristics across large areas of seafloor.

Development and evaluation of sediment quality guidelines based on benthic macrofauna responses

Toxicity-based sediment quality guidelines (SQGs) are often used to assess the potential of sediment contamination to adversely affect benthic macrofauna, yet the correspondence of these guidelines to benthic community condition is poorly documented. This study compares the performance of 5 toxicity-based SQG approaches to a new benthos-based SQG approach relative to changes in benthic community condition. Four of the toxicity-based SQG approaches--effects range median, logistic regression modeling (LRM), sediment quality guideline quotient 1 (SQGQ1), and consensus--were derived in previous national studies in the United States, and one was developed as a regional variation of LRM calibrated to California data. The new benthos-based SQG approach, chemical score index, was derived from Southern California benthic community data. The chemical-specific guidelines for each approach were applied to matched chemical concentration, amphipod mortality, and benthic macrofauna abundance data for Southern California. Respective results for each SQG approach were then combined into a summary metric describing the overall contamination magnitude (e.g., mean quotient) and assessed in accordance with a set of thresholds in order to classify stations into 4 categories of expected biological effect. Results for each SQG approach were significantly correlated with changes in sediment toxicity and benthic community condition. Cumulative frequency plots and effect category thresholds for toxicity and benthic community condition were similar, indicating that both types of effect measures had similar sensitivity and specificity of response to contamination level. In terms of discriminating among multiple levels of benthic community condition, the toxicity-based SQG indices illustrated moderate capabilities, similar to those for multiple levels of toxicity. The National LRM, California LRM, and the chemical score index had the highest overall agreement with benthic categories. However, only the benthos-based chemical score index was consistently among the highest performing SQG indices for all measures of association (correlation, percent agreement, and weighted kappa) for both toxicity and benthos.

Benthic macrofauna assemblages and biochemical properties of sediments in two Antarctic regions differently affected by climate change

Lipid, protein and carbohydrate concentrations have been determined in sediment cores from the continental shelf in the South Eastern Weddell Sea (SEWS), where no ice shelves have been present at least for thousands of years, and the continental shelf off the Eastern Antarctic Peninsula (EAP), in the area where two ice shelf collapses occurred in 1995 and 2002. On one hand, SEWS presents an important flux of fresh organic matter to the seabed during summer, whereas on the other hand, the presence of ice shelves in EAP hampered photosynthesis restricting the input of organic matter to advected refractory material. In the present study, biochemical variables and benthic macrofauna abundance, biomass and diversity confirmed differences between the two regions. Lipid concentrations were higher in SEWS than in EAP, whereas carbohydrate concentrations were higher in the latter region. These differences were attributed to the higher concentration of labile and refractory material, respectively. Biomass, abundance and diversity of the macrofauna were higher in SEWS than in EAP, where benthic communities started receiving a fresh organic matter input only after the recent ice shelf collapses. As regards macrofauna composition, both regions presented macrobenthic communities associated to early stages of recolonization.

Factors Affecting Benthic Impacts at Scottish Fish Farms

The factors affecting patterns of benthic [seabed] biology and chemistry around 50 Scottish fish farms were investigated using linear mixed-effects models that account for inherent correlations between observations from the same farm. The abundance of benthic macrofauna and sediment concentrations of organic carbon were both influenced by a significant, albeit weak, interaction between farm size, defined as the maximum weight of fish permitted on site at any one time, and current speed. Above a farm size threshold of between 800 and 1000 t, the magnitude of effects at farms located in areas of elevated current speeds were greater than at equivalent farms located in more quiescent waters. Sediment concentrations of total organic matter were influenced by an interaction between distance and depth, indicating that wind-driven resuspension events may help reduce the accumulation of organic waste at farms located in shallow waters. The analyses presented here demonstrate that the production and subsequent fate of organic waste at fish farms is more complex than is often assumed; in isolation, current speed, water depth, and farr size are not necessarily good predictors of benthic impact.

Temporal changes in the benthic macroflora of Lake Macquarie, a New South Wales coastal lagoon.

Between 1954 – 1956 the CSIRO Division of Fisheries carried out a study of the fish and related flora and fauna of Lake Macquarie. This was to determine whether there had been, as suggested, a reduction in the fish populations and, if so, whether it could be attributed to overfishing or some other cause. That study is summarised by Thomson (1959). As a part of that project a qualitative assessment of the distribution and abundance of benthic macrofauna was carried out (MacIntyre, 1959). Since then, only very limited benthic faunal sampling has been done in Lake Macquarie (Powis 1973, 1975). This paper presents qualitative information on the distribution and abundance of the macrofauna of the Lake collected between July 1979 and provides a comparison with the work done 23 years earlier.

Spatial Patterns of Macrobenthic Communities in Shallow-Water Tidal Embayments and Their Association with Environmental Factors

This study examines the distribution, composition, and structure of benthic communities in nine shallow-water semienclosed embayments on Cape Cod, southeastern Massachusetts. The spatial patterns were used to associate benthic characteristics with local environmental factors. Field data from multiple years were collected to measure macrofaunal abundance, community composition, and environmental characteristics. Multivariate statistics were used to analyze the spatial variations of species composition and the abundance of benthic macrofauna. Canonical ordination, specifically redundancy analysis, was used to determine the relative importance of the environmental factors (nutrients and habitat factors) being studied. The analyses demonstrate that the benthic communities in the shallow tidal embayments are clearly clustered in association with the local environments. Species composition and community structure of the benthic macrofauna are significantly correlated with water column parameters, especially with phytoplankton biomass, total nitrogen, and dissolved oxygen.

Impacts of trawling on benthic macro-fauna and -flora of the Spencer Gulf prawn fishing grounds

The overall effects of trawling on benthic habitats and their assemblages are dependent on the distribution and intensity of trawl effort. The benthic habitats of the Spencer Gulf prawn trawling grounds are subjected to known variable levels of trawling disturbance recorded from fisher's logbooks. These habitats have not been quantitatively investigated. The aim of the study was firstly to characterise the macro-faunal and -floral assemblages and secondly, to comparatively assess trawl impact by testing the null hypothesis of no differences between five sites exposed to different intensity of trawl effort. The distribution and abundance of benthic macro-fauna and -flora were studied at two sampling resolutions by using beam trawl sampling (∼10,000 m 2) and underwater stereophotography (∼4.5 m 2) at five sites with different levels of trawl disturbance (effort). The results showed that the Spencer Gulf prawn trawling grounds are characterised by sandy sediments with a low content of silt and clay, with the exception of one site with very fine gravel. Biomass, abundance and cover of macro-fauna and -flora were generally low throughout, but with large differences among sites. Biomass, abundance and cover were found to be negatively correlated to both trawl hours from 1994–1998 and during the period of study. ANOSIM and SIMPER analyses using biomass, abundance and percentage cover as variables showed significant differences between sites with eight species or taxonomic groups contributing more than 10% to the observed similarity within sites. The two northern sites were dominated by sponges and the bearded mussel, Trichomya hirsutus, and the southern hammer oyster, Malleus meridianus. Other species that contributed to the similarity within sites were the ascidian, Polycarpa viridis, mobile epifauna (the blue swimmer crab, Portunus pelagicus, and the western king prawn, Penaeus (Melicertus) latisulcatus) and demersal fish species (Degens leatherjacket, Thamnaconus degeni, and the Melbourne silver belly, Parequula melbournensis). Simpson's Index of Diversity (1 − λ) and species richness in the beam trawl samples were fairly even across all sites, but a significant effect of site was found in the stereophotographic transect samples. It was concluded that prawn trawling has a strong influence on the structure of the benthic habitats of the Spencer Gulf prawn fishing grounds highlighted by the magnitude of change and the strength of the gradient of effects. Confounding factors linked to the biophysical attributes of the sites are believed to be minor.

Temporal variability of benthic macrofauna on Cassino beach, southernmost Brazil

The temporal variability of benthic macrofauna on Cassino beach, southernmost Brazil, was studied for a period of one year (June 2004 to May 2005) based on monthly sampling. Three sites were selected distant 50m from each other. At each site, 3 transects were established, 2m equidistant from one another. Each transect extended from the base of the primary dunes to the inner surf zone at approximately 1m in depth, with 7 or 8 sampling levels. Within transects, the distance between the levels was 20m until the upper swash zone, from which distance was 10m until the 1-meter isobath. The temporal variation in the abundance of benthic macrofauna observed in the present study can be attributed to (1) the positive effects of the recruitment peaks and migration of particular species to the swash zone and (2) negative effects of the migration of some species to deeper waters, as well (3) as mortality through natural causes (stranding and action of predators) and (4) human causes (harvesting and vehicle transit). We attribute the expressive abundance increase of benthic macrofauna to recruitment. The stranding, that is, the trapping of the organisms on the upper parts of the beach, is likely the main cause of abrupt drops in benthic macrofauna abundance.

Composition and Abundance of Benthic Macrofauna of a Tropical Sea-Grass Bed in North Queensland, Australia

The aims of this study were to characterize the functional composition of benthic macrofauna of a tropical sea-grass bed and to determine temporal variations in abundance of benthic macrofauna in relation to environmental factors such as sea-grass biomass, temperature, salinity, and sediment type. Benthic macrofaunal composition and abundance were investigated by core sampler during April 1999, October 1999, March 2000, and August 2000 at three stations within a sea-grass bed at Cockle Bay in North Queensland, Australia. A total of 110 species of benthic macrofauna was collected. Polychaetes were the most abundant group (37 species; 52% of total macrofaunal numbers; 47% of biomass) followed by amphipods (27 species; 35% of total numbers). Decapods were also important, with 28 species contributing 31% of total macrofaunal biomass. Other miscellaneous groups were tanaids, isopods, and ophiuroids. Most amphipods (65%) and decapods (90%) were epifaunal, but polychaetes were equally represented by epifauna and infauna. Temporal variation in both species composition and abundance was large: the peak number of benthic macrofauna occurred in April 1999 and March 2000, and biomass was highest in April 1999. Benthic macrofauna numbers as well as biomass were lowest in August 2000. These temporal patterns of abundance of benthic macrofauna appeared to correlate closely with temporal variation of sea-grass biomass. In addition, the factors of life cycle and predation by common fish species may be indirectly associated with these patterns of macrofaunal abundance.

Periphyton communities in experimental marine ecosystems: scaling the effects of removal from container walls

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 271:27-41 (2004) - doi:10.3354/meps271027 Periphyton communities in experimental marine ecosystems: scaling the effects of removal from container walls Chung-Chi Chen1,2, W. Michael Kemp1,* 1University of Maryland Center for Environmental Science, Horn Point Laboratory, PO Box 775, Cambridge, Maryland 21613, USA 2National Taiwan Normal University, Department of Life Sciences, Taipei, Taiwan 116, ROC *Corresponding author. Email: kemp@hpl.umces.edu ABSTRACT: Although it is widely held that growth of periphyton communities on walls of marine mesocosms creates artifacts which bias experimental results, there are surprisingly few studies that directly quantify such Œwall effects¹. To test the hypotheses that the magnitude of wall effects is related to experimental system dimensions and that these effects can be controlled by routine periphyton removal, we conducted a series of studies using cylindrical mesocosms of 5 different sizes and shapes with treatments involving removal of wall periphyton. Results indicate that periphyton biomass and production were consistently and significantly reduced in containers receiving twice-weekly wall-cleaning treatment, but not in systems cleaned at weekly intervals. Whereas partitioning of ecosystem properties (total primary production and algal biomass) among wall, plankton, and sediment habitats revealed large and significant changes with wall-cleaning, treatment effects on the mean values of these and other ecosystem-level properties (e.g. nutrient concentrations) were small to negligible and generally inconsistent. Changes in biomass of wall periphyton and phytoplankton induced by wall-cleaning were significantly related to mesocosm radius. Reductions in wall periphyton with cleaning treatment were generally compensated by parallel increases in algal biomass in other habitats, with enhanced sediment microalgae only present in shallower systems. It appears that wall-cleaning also affected the abundance of benthic macrofauna and bacterioplankton, as well as phytoplankton taxonomic composition. Although periphyton dislodged through wall-cleaning were retained within the mesocosms in this study, we estimate that removal of this material from the experimental systems would have caused a severe nitrogen loss, equivalent to that required for supporting total ecosystem primary production. KEY WORDS: Mesocosms · Experimental ecosystems · Scale · Wall-cleaning · Periphyton · Phytoplankton · Gross primary production · Sediment microalgae · Nutrients Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 271. Online publication date: April 28, 2004 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2004 Inter-Research.

Benthic metabolism and sulfur cycling along an inundation gradient in a tidal Spartina anglica salt marsh

Central aspects of carbon and sulfur biogeochemistry were studied along a transect extending from an unvegetated mudflat into a Spartina anglica salt marsh. Conditions along the transect differed with respect to tidal elevation, sediment characteristics, vegetation coverage, and benthic macrofauna abundance. Dark sediment O2 uptake and CO2 emission at the highly bioturbated mudflat were low and relatively unaffected by tidal coverage. Sulfate reduction accounted for 30–60% of the daily CO2 emission from the open mudflat sediment. Sediment O2 uptake within the nonbioturbated and vegetated marsh was up to seven times higher during air exposure than during inundation, whereas the difference in CO2 emissions always was less than a factor of 2. The contribution of sulfate reduction to CO2 production was low (<21%) and decreased progressively with tidal elevation as a result of the oxidizing capacity of S. anglica roots in the vegetated marsh. The boundary between the mudflat and the retreating marsh is a unique environment. High near‐surface pore‐water concentrations of dissolved organic carbon (DOC) above the marsh cliff and highly elevated total carbon dioxide (TCO2) pore‐water concentrations at both sides of the cliff during air exposure coincided with extremely high TCO2 emissions and apparent respiratory quotients (up to 14) only below the marsh cliff during inundation. We propose that substantial seepage of DOC‐poor and HCO2−‐rich pore water may have occurred from the elevated marsh to the unvegetated sediment below during low tide followed by massive release of HCO3− during high tide. Accordingly, sulfate reduction accounted for more than the TCO2 release above the marsh cliff, but only for about 40% below the cliff. Mineralization rates and pathways in salt–marsh sediments vary considerably on small spatial and temporal scales and are dependent on inundation frequency as well as the composition and distribution of flora and fauna.

Effects of shrimp-trawling on abundance of benthic macrofauna in Gullmarsfjorden, Sweden

Hypotheses about effects of shrimp-trawling on large benthic macrofauna were tested in a manipulative experiment in Gullmarsfjorden, Sweden. The experiment lasted 1.5 yr and included 3 trawl sites and 3 control sites, each of which was sampled at 4 times before and 4 times after trawling was commenced (a total of 480 samples). Gear and intensities were chosen to approximate those before trawling was prohibited 6 yr before the experiment. The overall trend was that biomass and abundances of animals decreased as a consequence of trawling but few taxa differed significantly among treatments. The mean abundance of echinoderms, in particular the brittlestars Amphiura sp., decreased significantly and substantially after 7 to 12 mo of trawling. In general, however, changes in abundances of animals from one time of sampling to another, and from before to after trawling started, differed among sites. General models based on size and feeding strategy did not accurately predict differences among taxa in sensitivity to disturbances. Differences in overall impacts between this and previous experiments are discussed in terms of fishing intensity, natural variability and experimental design.

Dissolved silica concentrations and reactions in pore waters from continental slope sediments offshore from Cape Hatteras, North Carolina, USA

The pore water concentrations of dissolved silica in sediment cores from the continental slope offshore from Cape Hatteras, North Carolina, varied from 150 to almost 700 μ, M with depth in the top 40 cm of sediment. Sediment cores from 630 to 2010 m depth had very similar profiles of dissolved silica in their pore waters, even though these cores came from regions greatly different in slope, topography, sedimentation rate, and abundance of benthic macrofauna. Cores from 474 to 525 m were more variable, both with respect to pore water dissolved silica profiles, and with respect to sediment texture. Experiments indicate that both the rate of dissolution of silica and the saturation concentration decrease as sediment depth below the sediment-seawater interface increases. These data are consistent with depletion of a reactive silica phase in surface sediment, which may be radiolarian tests, or the alteration of biogenic silica to a less reactive form over time. Experimental results suggest that the pore water dissolved silica concentration in sediments below the top few centimeters may be higher than the sediments could now achieve. The flux of dissolved silica out of these sediments is estimated to be 15 μmoles cm −2 yr −1 .

A Multidisciplinary Approach to Evaluating Impacts of Shellfish Aquaculture on Benthic Communities

The impact of suspended mussel culture (Mytilus edulis, M. trossulus) on the benthos of a small Nova Scotia cove (7 m depth) was assessed using meehods involving both benthic metabolism and community structure. Due to deposition of mussel feces and pseudofeces, sedimentation rate was higher under the mussel culture lines than at an adjacent reference site of similar sediment texture. Porewater profiles of sediment sulfate and sulfide indicated greater anaerobic metabolism at the mussel site than at the reference site, but sulfide was absent from the upper centimeters of sediments under the mussels. Seasonal measures of sediment oxygen demand showed little change between sites, but maximum rates of ammonium release at the mussel site were twice the highest rates measured at the reference site. Abundance of benthic macrofauna was higher at the reference site, but biomass was generally lower. Biomass at the mussel site was dominated by molluscs (Ilyanassa spp. andNucula tenuisulcata), that were attracted to mussels fallen from the culture and/or enriched organic matter due to biodeposition. Species diversity was lower at the reference site due to the dominance of the polychaeteNephtys neotena. Abundance-biomass comparisons (ABC method) of faunal analysis did not indicate any impact of biodeposition at this site: however, disturbance did not result in a typical assemblage of small opportunistic species anticipated with this method. Cluster analysis of macrofauna usually provided a clear separation between the sites. Since the contruction of a causeway (1968), foraminifera species composition showed a temporal response to temperature changes in the cove by shifting toward calcareous species, but assemblages downcore showed little or no relationship to aquaculture impacts. Although there is a shift toward anaerobic metabolism at the mussel lines, the impact of mussels falling to the sediments was more noticeable in benthic community structure than was any impact due to organic sedimentation or hypoxia. In general the impact of aquaculture on the benthos appeared to be minor. Furtyher assesment of these consequences may mandate both taxonomic and energetic approaches to impact assessment.

An ultrasonic thickness measuring instrument using transistor logic techniques: Elliot, B.L. Electrical Engineering, 35, No. 429, p. 738 (1963)

Acoustic backscatter from multi-beam echo-sounder (MBES) and dual-frequency single-beam echo-sounding systems (SBES) operable at 95 kHz and 33/210 kHz, respectively, were used to study the distribution of sediment texture and benthic macro-fauna along the central part of the western continental shelf of India (off Goa). To characterize the continental shelf seafloor, single-beam and multi-beam backscatter signals were acquired along with grab sediment samples. The relationships between processed acoustic backscatter strength, grain size, and benthic macro-fauna abundance were demonstrated employing clustering technique (PCA) and Geographic Information System (GIS) based mapping. The clustering analysis delineated that the backscatter values at three frequencies are strongly correlated with both substrate type and faunal functional groups. The preferences of deposit feeders (soft body benthic macro-fauna) for the fine-sediment regions and filter feeders (hard body benthic macro-fauna) for coarse sediment regions were linked to the variations in sediment granulometry as well as backscatter strengths in the study area. This study further demonstrates the utility of high frequency backscatter data employing echo-sounding systems towards the interpretation of seafloor sediments and benthic habitat characteristics across large areas of seafloor.