Biota Species Research Articles

Relações entre diversidade íctia e fatores hidrodinâmicos de um riacho na bacia do rio Uruguai

Fatores físicos, químicos e ambientais em um curso de água podem influenciar a estrutura e a diversidade das espécies da biota aquática. Entre os fatores físicos têm-se as condições hidrodinâmicas. Variações do escoamento resultam em dinâmicas complexas das populações e comunidades de peixes. Este trabalho tem por objetivo avaliar as correlações entre as variáveis hidrodinâmicas no Arroio Fortaleza, afluente do rio Uruguai, e a diversidade das espécies. A metodologia compreendeu a coleta de dados hidrodinâmicos (profundidade média da coluna de água, velocidade média do escoamento e vazão escoada na seção fluviométrica) e biológicos (coleta de peixes nas áreas de influência das seções fluviométricas). Com os dados biológicos foram calculados os seguintes índices: o de diversidade de Shannon, o de equitabilidade e o de similaridade. Coletaram-se 527 exemplares, de 25 espécies, dentre elas 4 exóticas e 4 ainda não classificadas. Essas 25 espécies estão classificadas em 4 ordens, 7 famílias e 13 gêneros. O índice de Shannon variou entre 1,43 e 2,68 nats/indivíduo. O índice de equitabilidade foi sempre superior a 0,8, indicando que os indivíduos estão bem distribuídos entre as diferentes espécies. O índice de similaridade de Jaccard variou entre 20 e 80%. Os menores valores foram obtidos para a área amostral situada próximo da nascente. As correlações entre o índice de Shannon e as características hidrodinâmicas resultaram em coeficientes R² variando entre 0,59 e 0,83. Estes resultados evidenciam que a diversidade das espécies é influenciada pelas características hidrodinâmicas. No entanto, a profundidade da coluna de água ou a velocidade média do escoamento não são suficientemente significativas para explicar a variabilidade espacial da diversidade das espécies isoladamente.

210Po accumulation by components of the Black Sea ecosystem

The naturally occurring radionuclide 210 Po was determined in different components of the Black Sea ecosystem. The specific activity of 210 Po in water in the open part of the sea was about 1Bq ⋅ m-3 . The range of 210 Po specific activity in bottom sediments was 4.5–500 Bq ⋅ kg-1 dry weight depending on their type, area and depth of collection. The highest values were found in the NW part of the Black Sea. Sediment distribution coefficients (Kd) of 210 Po for bottom sediments, calculated on a dry weight basis, varied from 0.5 × 104 to 5 × 105 . The levels of 210 Po specific activity in molluscs and pelagic fishes anchovy and sprat were the highest among the investigated species of the Black Sea biota. Concentration factors (CF) of 210 Po, estimated on a wet weight basis, reached 1.5 × 103 for macrophytes, 4 × 103 for total zooplankton, 103 –104 for the entire fishes depending on their ecological groups affiliation and (0.7–6.0) × 104 for molluscs. So, the ability of the Black Sea biota to accumulate the natural radionuclide 210 Po is comparable with that of similar species from others marine and oceanic areas.

Modelling the long term dispersion of radioactive liquid effluent and dose from marine pathways using a grid model

A grid model was developed to combine small-scale grid resolution and long-term predictions of radionuclide dispersion in shallow seas. A predictor-corrector algorithm ensures an unconditional stability of the model. Four modules calculate the concentration of suspended sediments, the dispersion of radionuclides in the marine environment, and the doses to members of the public and marine biota. The model was applied to the dispersion of liquid effluent in the Irish Sea from the Sellafield nuclear reprocessing plant, Cumbria (UK). The concentration factors and partition coefficients have been calibrated for biota species and local conditions. The validation against environmental samples for twenty-two radionuclides shows a good agreement between predicted and measured values.

Bioaccumulation of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in wild aquatic species from an electronic waste (e-waste) recycling site in South China

Water and several wild aquatic species including Chinese mysterysnail, prawn, fish, and water snake were collected from a reservoir surrounded by several e-waste recycling workshops in South China. The samples were examined to investigate the levels and bioaccumulation extent of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) released from electronic waste (e-waste) which was processed by crude recycling method. Elevated levels of PBDEs [52.7 to 1702 ng/g wet weight (ww)] and PCBs (20.2–25958 ng/g ww) were found in the collected biota species compared to that in the reference samples (13.0–20.5 ng/g ww for PBDEs and 75.4–82.8 ng/g ww for PCBs). log BAF (bioaccumulation factor) ranged from 2.9 to 5.3 for PBDEs and from 1.2 to 8.4 for PCBs, depending on congeners and species. The relationship between log BAFs and log K OW (octanol–water partition coefficient) can be adequately described by species-specific parabolic models wherein log BAFs generally increased at log K OW < 7 then decreased with further increasing log K OW both for PBDEs and PCBs. The exceptions were for Chinese mysterysnail and prawn, in which the log BAFs showed a positive linear correlation with log K OW for PBDEs. Some PBDE and PCB congeners showed BAF values declining from the general trend predicted by K OW, largely attributing to metabolism of these congeners in species sampled.

Bioaccumulation of platinum group metals on some fish species ( Oreochromis niloticus , Penaeus laspisulcates , Scylla serrate , Galaxias brevipinnis and Mollusc ) in the Pra estuary of Ghana

Catalytic converters have been designed to solve the problem of pollution from automobiles. However, recent studies have shown that the platinum group metals (PGMs) that are used in the design are being deposited alongside highways. The objective of this study was to measure the levels of PGMs that bioaccumulate in Oreochromis niloticus, Penaeus laspisulcates, Scylla serrate, Galaxias brevipinnis and Mollusc in the river Pra estuary along a major highway in Ghana. Chemical analysis using neutron activation analysis showed accumulation of the PGMs in all the biota species analysed. The S. serrate and mollusc showed higher accumulation than the other species. The mollusc and the other fish species in the estuary are consumed in Ghana, and therefore there is the need to educate the population on the effect of the PGMs on their health.

Improving analytical confidence in the determination of PCBs in complex matrices by a sequential GC-MS/MS approach

A method is described for achieving increased confidence in the selective determination of PCBs using capillary gas-liquid chromatography with tandem mass spectrometry (GC-MS/MS). It is well known that quantitation of PCBs by MS is susceptible to a false positive interference that arises from the co-elution of a higher PCB homolog with a lower PCB homolog (i.e., M-Cl+ from a higher homolog is M+ for a lower homolog). Because the elution order of the PCB congeners is not exactly proportional to increasing Cl content, frequent switching from MS/MS windows for specific homologs must take place. This approach can yield significant errors when matrix-induced retention time shifts occur. We therefore explored an alternative approach that involves repetitive analyses of a single extract. We developed and optimized a method that requires three injections, with homolog classes sequentially monitored as: 1-4-7-10, 2-5-8, and 3-6-9, respectively. The sequential design of the method entails the use of separate, broad MS/MS windows for each homolog class, thereby minimizing adverse matrix effects on retention variability. However, a consequent tripling of overall analysis time is incurred for each sample. The homolog classes are determined with high confidence (99%) that overlapping higher homolog fragments do not interfere with the quantitation of lower homologs. The method was demonstrated for extracts in small samples (∼750–1000 mg) from seven different freshwater biota species (n = 20) to illustrate a wide range of matrix-induced shifts. Application of the method resulted in more accurate quantitation, correcting an average 5.3% relative error (false positive bias) in observed concentration.

Effects of oil pollution at Kuwait’s greater Al-Burgan oil field on polycyclic aromatic hydrocarbon concentrations in the tissues of the desert lizard Acanthodactylus scutellatus and their ant prey

Using indicator species to monitor the effects of oil pollution was thought to be useful to assess whether local desert reptiles and their insect prey could fulfill such a role in an area damaged in the second Gulf War (1990). Polluted sites with apparently different degrees of contamination (namely tar mat, soot, and clear sites) located at Kuwait's Greater Al-Burgan oil field were compared with control areas outside this region in study conducted in 2002. Five Acanthodactylus scutellatus lizards from each study and control site were humanely killed and stored in a freezer at -20 degrees C until analysis. Ants from the same sites were also collected and treated in a similar manner. Lizard and ant whole body tissues were subjected to gas chromatography-mass spectrometry (GC-MS) to determine concentrations of petroleum hydrocarbons (HCs). The study concentrated on sixteen polycyclic aromatic hydrocarbons (PAHs), EPA priority pollutants used as indicators of petrogenic HC contamination. There were significantly different concentrations of total PAHs in lizards and ants among all four study sites. Of the 16 PAHs, phenanthrene, fluoranthene, and benzo[a]anthracene were present in both lizard and ant samples from the Greater Al-Burgan oil field sites irrespective of the apparent degree of pollution but were undetectable in materials from the control sites. The range of total PAHs in lizards was 26.5-301 ng g(-1) and it was 6.7-82.1 ng g(-1) in ants. Concentrations increased progressively along an expected contamination gradient. Total PAHs were detected in biota even in an area (clear site) that did not appear, virtually, to contain petroleum soil pollution which supports the value of indicator biota species. For all three sites where PAHs were found in biota, the ratio of total PAHs in ants to lizards was consistently 3.3-3.4. These data show that, although 12 years have passed since the Kuwait oil spill catastrophe, all sites are still contaminated with PAHs. Use of lizard and ant materials in monitoring such desert locations seems to be an effective strategy.

Effect of Municipal Sewage Treatment Plant Effluent on Bioaccumulation of Polychlorinated Biphenyls and Polybrominated Diphenyl Ethers in the Recipient Water

Water, sediment, and aquatic species including plankton, fish, and turtles were collected from a small lake in Beijing, which receives effluent discharged from a large sewage treatment plant (STP). The samples were examined to investigate polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) releases from a STP and their distributions in the lake. The accumulations of sigma 12PBDEs and BDE-209 in the sediment were 62.3 and 1150 ng/cm2, respectively, while that of sigma PCBs was 99.3 ng/cm2. BDE-209 was detected in more than 50% of the aquatic species. A strong linear correlation (R2 = 0.92) was found between sigma 12PBDEs and sigma PCBs levels in aquatic species but not in sediments. The different PBDE congener profiles in sediments and biota samples suggest metabolic debromination in the sampled fish. Bioaccumulations of PBDEs and PCBs were found in aquatic species.The logarithm bioaccumulation factor (BAF) decreases with the number of bromines in PBDEs molecules, while the log BAF versus the number of chlorines in PCBs appears to be parabolic. Biomagnifications of these compounds were not obvious in the food web by analysis of the relationship between sigma 12PBDEs or sigma PCBs levels and the trophic level of aquatic biota species.

Polybrominated diphenyl ethers in biota and sediments of the Pearl River Estuary, South China

Polybrominated diphenyl ethers (PBDEs) were analyzed in three invertebrate species, five fish species with different living and feeding habits, and surface sediments collected from the Pearl River Estuary, South China. The concentrations of 10 PBDE congeners (BDEs 28, 47, 66, 99, 100, 85, 154, 153, 138, and 183) ranged from 34.1 to 444.5 ng/g lipid and from 9.88 to 39.0 ng/g organic carbon in biota and sediment samples, respectively. In sediments and some biota samples, BDE 209 was found as the major congener, ranging from nondetectable to 623.5 ng/g lipid in biota samples and from 792 to 4,137 ng/g organic carbon in sediment samples. Different levels of PBDEs in various biota species were attributed to the different feeding habits of the aquatic species or their ability to metabolize PBDE. Different congener profiles between the biota and sediment samples were observed and attributed to the bioaccumulation potential or the ability to metabolize individual BDE congeners. Polybrominated diphenyl ether levels in the biota from the Pearl River Estuary correlated well with lipid contents but did not correlate with the biota lengths. The distribution of biota-sediment accumulation factors for individual PBDE congeners was consistent with the general pattern predicted from a widely used bioaccumulation model.

Petroleum Hydrocarbons Accumulation Potential of Shellfishes from Littoral Waters of the Bight of Bonny, Niger Delta, Nigeria

Total hydrocarbons concentration in four commercially available shellfishes (Ocypoda africanus, Macura reptantia, Procambarus clarkii and Penaeus notialis) from coastal waters of the Niger Delta region of Nigeria were investigated between June 2003 and February 2004 using standard methods. Levels of total hydrocarbons varied significantly depending on biota species, feeding habit and season. The seasonal mean concentrations reported were: 3.98±0.69, 7.95±1.18, 2.24±0.39 and 5.85±0.57 µg g-1 dry weight for M. reptantia, O. africanus, P. clarkii and P. notialis respectively during the wet season. Enhanced concentrations recorded during the dry season were 7.81±2.32, 11.59±2.63, 6.16±2.12 and 9.69±1.90 µg g-1 dry weight for M. reptantia, O. africanus, P. clarkii and P. notialis respectively. The results obtained indicated seasonal variations which might have been associated with an incidental crude oil spill recorded during the investigation. In general, O. africanus showed higher levels of total hydrocarbons than other species investigated. However, biota species demonstrated hydrocarbon bioaccumulation potential. Regression between the monthly concentrations of total hydrocarbons in each of the biospecimens with the levels in the surface water and sediments indicated statistically significant (p<0.05) relationships. Moreover, comparison of the seasonal mean concentrations using paired sample t-test at 95% confidence level indicated that the concentrations between the dry and wet seasons were statistically significant.

A checklist of the Scelionidae (Hymenoptera: Platygastroidea) of India

© Zoo Outreach Organisation; www.zoosprint.org Manuscript 1570; Received 26 May 2006; Finally accepted 18 October 2006; Date of publication 21 November 2006 The Hymenoptera is one of the most species rich orders, with about 10% of all known species of the terrestrial biota, of which 80% are parasitic placed under 10 superfamilies (Masner, 1993). The Platygastroidea which includes two families viz., the Scelionidae and the Platygastridae, is the third largest of the parasitic superfamilies, with about 4460 described species worldwide. They are found virtually in all habitats except the polar regions and are particularly diverse and abundant in the wet forests of the tropics and subtropics (Austin et al., 2005).

Genotoxicity and cytotoxicity assay of water sampled from natural reservoirs with contrast level of radioactive and chemical contamination

Comparative analysis of water from natural reservoirs located near a place of the underground nuclear explosion with rock outburst (Perm region) and the radium production industry storage cell (Komi Republic) with contrast levels of radioactive and chemical contamination was performed for the first time using bioindication and chemical analysis. Bioindication was carried out with anaphase-telophase chromosome aberration assay on A. schoenoprasum L. meristematic root tip cells. Even at very low levels of specific activity, both natural (238 U, 232 Th, 226 Ra, 210 Po, 210 Pb) and artificial (90 Sr, 137 Cs, Pu) radionuclides contribute significantly (59-91 %) to an induction of genotoxic and toxic effects. The chemical factors strengthened or weakened the cytotoxicity effects and may modify a formation of certain type of chromosome disturbances. Our results clearly indicate that combined exposure to metal ions and radionuclides at levels officially adopted as permissible for humans may act synergistically and result in significant damage to different biota species.

Persistent organic pollutants in mangrove food webs in Singapore

In this study, persistent organic pollutants were quantified in sediments, subsurface seawater, sea-surface microlayer and twenty-four biota species collected at two separate mangrove habitats in Singapore. Data confirmed the ubiquity of POPs, including polybrominated diphenyl ethers (PBDEs), in the marine environment of Singapore. A biomagnification phenomenon was observed amongst the species collected and analysed from both mangrove sites studied. Thunder crabs and fish displayed the highest POP levels. Congener profiles of PBDEs varied amongst mangrove biota species and suggested different metabolic pathways exist for flame retardants. Similarly, crab species showed an ability to metabolize chlordane insecticide.

Reconnaissance isotopic and hydrochemical study of Cuatro Ciénegas groundwater, Coahuila, México

The springs of the Cuatro Ciénegas bolson (Four Marshes basin), Coahuila, México, support more than 70 endemic species of biota. The specifics of the groundwater flow regime, however, remain a mystery. Water samples were collected from a series of springs and pools and one canal in the Cuatro Ciénegas bolson and analyzed for field parameters (temperature, pH, conductivity, alkalinity) and stable oxygen and hydrogen isotopes in an attempt to begin a systematic study of the hydrogeology of the region. Groundwaters discharging directly along a fault-controlled spring line in Cretaceous carbonate rocks of the Cupido-Aurora aquifer are the most dilute (lowest conductivities) and warmest of those sampled. Cuatro Ciénegas waters are characterized by circumneutral pH (6.9–7.7) and reasonably low alkalinity (160–215 mg/kg as HCO 3). The δ 18O values of Cuatro Ciénegas waters range from −8.2 to −5.7‰, with a mean of −6.5±0.82‰, whereas δD ranges from −52 to −43‰, with a mean of −46.6±3.2‰. The majority of the water samples plot subparallel and beneath the local meteoric water line; those samples collected farthest from the spring line exhibit the most enriched δ 18O and δD values. The stable isotope data indicate that isotopic enrichment of groundwaters by evaporation following discharge and subsequent surface flow is an important process within the Cuatro Ciénegas bolson. The isotope data also suggest that a fraction of Cuatro Ciénegas groundwater originates with local recharge in mountains surrounding the bolson. Those springs that issue from the western base of the Sierra de San Marcos mountain range are recharged in part in these mountains, whereas groundwaters discharging from Laguna Anteojo in the northern part of the bolson are more likely recharged in the higher San de la Madera mountain range. An estimate of the water balance suggests that interbasin flow also may contribute to the considerable groundwater discharge.

Hyperspectral discrimination of coral reef benthic communities in the western Caribbean

Determining a subset of wavelengths that best discriminates reef benthic habitats and their associated communities is essential for the development of remote sensing techniques to monitor them. This study measured spectral reflectance from 17 species of western Caribbean reef biota including coral, algae, seagrasses, and sediments, as well as healthy and diseased coral. It sought to extend the spectral library of reef-associated species found in the literature and to test the spectral discrimination of a hierarchy of habitats, community groups, and species. We compared results from hyperspectral reflectance and derivative datasets to those simulated for the three visible multispectral wavebands of the IKONOS sensor. The best discriminating subset of wavelengths was identified by multivariate stepwise selection procedure (discriminant function analysis). Best discrimination at all levels was obtained using the derivative dataset based on 6–15 non-contiguous wavebands depending on the level of the classification, followed by the hyperspectral reflectance dataset which was based on as few as 2–4 non-contiguous wavebands. IKONOS wavebands performed worst. The best discriminating subset of wavelengths in the three classification resolutions, and particularly those of the medium resolution, was in agreement with those identified by Hochberg and Atkinson (2003) and Hochberg et al. (2003) for reef communities worldwide. At all levels of classification, reflectance wavebands selected by the analysis were similar to those reported in recent studies carried out elsewhere, confirming their applicability in different biogeographical regions. However the greater accuracies achieved using the derivative datasets suggests that hyperspectral data is required for the most accurate classification of reef biotic systems.

The use of coal fly ash in concrete for marine artificial reefs in the southeastern Mediterranean: compressive strength, sessile biota, and chemical composition

To examine the possible use of coal fly ash (CFA) in concrete for artificial reefs, blocks containing 0%, 40%, 60%, and 80% CFA as a substitute for sand were deployed in the Mediterranean at 18.5-m depth off the coast of Israel during a period of 33 months. Changes in compressive strength, composition, and coverage of sessile biota species, as well as in trace element concentration of the block surface and in sessile biota from four taxonomic groups, were determined as a function of time at sea and block type. Compressive strength clearly increased with time in all types to values well above the minimal strength considered necessary for stability of the blocks at sea. Moreover, the 40% and 60% CFA blocks were 1.5 times stronger than the 0% and 80% ones. Main sessile taxa recorded were filamentous green algae, bryozoa, barnacles, serpulid polychaeta, hydrozoa, and bivalves. Number of species settled and biotic coverage varied among block side and seasonally, but did not differ significantly between block types. The initial heavy metal composition (Hg, Cd, Pb, Cu, Zn, Cr, Mn, Fe, Al) of the block material was directly proportional to the CFA percentage. At the end of the study, Pb had decreased in all types, Cd in the 60% CFA block, and Fe and Al in the 40% and 60% blocks, while Mn had increased in the blocks with 0% and 80% CFA. After 21 months at sea, the only detectable change was a decrease in Pb concentration in all types, indicating that changes may be due to long-term processes. Trace metal levels (Hg, Cd, Zn, Mn, Cu, Fe, and Al) were measured in the sessile biota (hydrozoa, polychaeta, and bivalvia). In most cases, no dependence was found between metal levels and time at sea or CFA content of the blocks. In the hydroid, metal concentration even decreased over time. Copyright 2002 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights reserved .

An investigation into the composition, complexity and functioning of snake communities in the mangroves of south‐eastern Nigeria

AbstractThe structure of the snake community was studied between 1996 and 2000 on a transect in the mangrove ecological zone of southern Nigeria, West Africa. In three major habitats, both taxonomical diversity and frequency of observations in relation to sampling effort were investigated. In general terms, the complexity of the snake community appeared less than in other habitats of the same geographic region (i.e. swamp forest and forest–plantation mosaics). In fact, only eighteen species were recorded, whereas 43 species are known to inhabit neighbouring habitats. A Principal Component Analysis allowed arrangement of the various species into two main groups in relation to the habitats of capture: (1) a group of species of rainforest biota (i.e. Toxicodryas blandingii, Thelotornis kirtlandii, Thrasops flavigularis, Rhamnophis aethiopissa, Gastropyxis smaragdina, Grayia smythii, Pseudohaje goldii, Python sebae), and (2) a group of species that, at least in Niger Delta, are typically linked to altered habitats, including derived savannas, plantations and suburbia (i.e. Psammophis cf. phillipsi, Philothamnus cf. nitidus, Hapsidophrys lineatus, Crotaphopeltis hotamboeia, Boaedon lineatus, Naja nigricollis, Python regius). The community structure in terms of food habits and body sizes appeared similar to those of other snake assemblages from different habitats of southern Nigeria. The conservation implications of our results are also discussed.

Assessment of doses for Arctic marine biota

The objectives of this paper are the presentation of site-specific radioecological information and development of models, which can be used to calculate doses to Arctic marine biota. The methodology of calculating doses from a, P, and y-emitters is presented. This methodology is realized in form of computer code DOSBIO, and model parameters are evaluated. The following annual doses to biota are calculated: internal dose from radionuclides incorporated in the organisms; external dose from contaminated water; external dose from contaminated bottom sediments; total dose as a sum of internal and external doses. Dose conversion factors are calculated for 15 species of marine biota, including fish, sea mammals, molluscs. The list of species includes cod, plaice, haddock, herring, redfish, Greenland halibut, char, saithe, Greenland seal, white whale, ringed seal, bearded seal, and others. The calculations are performed for adult representatives of each species. Calculated dose conversion factors are presented for 11 different radionuclides (H-3, C-14, K-40, Sr-90, Tc-99, Sb-124, Cs-137, Eu-152, Po-210, Pu-239, Am-241). The current and potential doses to marine biota from the Barents and Kara Seas are estimated.

Radioecological modelling and the computer codes for calculations of doses to marine biota and man in the Arctic

Methodology and computer code DOSBIO are described for assessment of radiation doses to Arctic marine biota, and model parameters are evaluated. The algorithm and computer code DOSMAN are described for assessment of dose to man from consumption of arctic seafood products (fish, crustaceans and molluscs). The computer codes DOSBIO and DOSMAN are user-friendly tools for assessing the radioecological situation in the marine environment and analyzing the impact of technogenic radionuclides to both man and biota. The calculated values of dose conversion factors for 15 key species of arctic marine biota from exposure to 35 radionuclides are presented; dose conversion factors are given for internal and external exposure of arctic marine biota. The doses to Arctic marine biota and man were calculated from model runs, using actual environmental activity levels.

Ecological risk assessment of polychlorinated biphenyl contamination in the Mai Po Marshes Nature Reserve, Hong Kong

The main objective of the present study was to investigate polychlorinated biphenyl (PCB) contamination in Mai Po Marshes Natural Reserve, Hong Kong. During June–December 1997, samples of sediments and aquatic organisms including fish ( Oreochromis mossambica× O. nilotica, Mugil cephalus) and shrimps ( Metapenaeus ensis, Macrobrachium nipponense), were collected from gei wais and total PCB levels were measured. The concentrations of PCBs in sediments reduced gradually from coastal sites (8.13 ng g −1 dry wt) to landward sites (1.47 ng g −1 dry wt), which suggested that PCBs in Deep Bay waters were the main input source entering the reserve. The calculated PCB concentrations in water were generally safe for aquaculture according to the U.S. EPA guidelines, but PCBs in muscle tissues of grey mullet ( Mugil cephalus) exceeded the guidelines. PCB concentrations (ng g −1 lipid) in tilapia increased with increases in fish body size, which was possibly due to active uptake of PCBs by tilapia. Within the same shrimp species, different sized organisms showed similar PCB contents in lipid, indicating that lipid content rather than body size determined body concentrations. The PCB concentrations in the aquatic organisms in the reserve posed no hazards to birds according to predicted egg toxicity effects. The estimated BSAFs (biota-sediment accumulation factors) obtained in the present study ranged from 1.10 to 2.37, which were similar to the reported value of 2.10 derived from various aquatic biota species.