Effects of oil dispersants on the developing embryos of marine fish

The effects of oil dispersants BP1002¹, Finasol ESK and Corexit 7664 on the development of herring, Clupea harengus L., plaice, Pleuronectes platessa L. and sole, Solea solea (L.) have been studied. Treatment of developing embryos for 100 h with BP1002 and Finasol ESK gave rise to abnormalities in cell division and differentiation, to reductions in heart-rate, eye pigmentation, growth rate and hatching success above concentrations of 10 parts/10⁶. Larvae with abnormal flexures of the spine, which prevented them from feeding successfully, resulted from exposure to 5 parts/10⁶. Treatment of the embryos with dispersants throughout the period from fertilisation to hatching (15 to 20 days) produced similar abnormalities at slightly lower concentrations. Corexit did not produce any demonstrable deleterious effects on embryos exposed to concentrations up to 5000 parts/10⁶, the highest tested.     

Biological effects of surface active agents on marine animals

The biological effects of 5 surface active agents (the anionic ABS, LAS and LES 3 EO and the nonionic NP 10 EO and TAE 10 EO) on marine fishes, crustaceans and bivalves have been tested in, continuous-flow systems. Concentrations from 100 to 0.5 ppm were normally used. Fishes were found to be more susceptible (96 hLC 50 range: 0.8 to 6.5 ppm) than bivalves (96 hLC50 range: 5 to >100 ppm) while crustaceans were considerably more resistant (96 h LC 50 range: 25 to > 100 ppm). Within each of these 3 systematic groups, more active species were found to be more sensitive than less active species. Developmental stages were also more sensitive than adults. The resistance of crustaceans to surfactants decreases immediately after moulting. The most toxic agent for fishes and decapods was the soft anionic LAS, and for bivalves and barnacles the hard nonionic NP 10 EO. Ability to recover normal behaviour after exposure decreases with increasing concentration and time, and ceases earlier in anionic than in nonionic surfactants. The first reaction to the surfactants is increased activity (avoidance reaction of mobile species), followed successively by inactivation, immobilization and death. Nonionic surfactants affect the equilibrium in fishes. Sublethal effects appear as impaired locomotory activity and breathing rate in fishes and crustaceans, impaired byssus activity and shell closure in Mytilus edulis, burrowing in Cardium edule, Astarte montagui and Astarte sulcata. Siphon retraction is affected in Mya arenaria and Cardium edule, as is also the response to food of the Leander spp.     

Distribution,diet and habitat selection by four sympatrically breeding gull species in the south-eastern North Sea

Food choice, feeding habitat use and spatial distribution of black-headed gulls ( Larus ridibundus), mew gulls ( L. canus), herring gulls ( L. argentatus) and lesser black-backed gulls ( L. fuscus) were studied in the south-eastern North Sea. At-sea distribution during the breeding period was assessed by transect counts from ships. Clear differences could be established between the four species, with lesser black-backed gulls being widespread and numerous far out at sea and mew and black-headed gulls being restricted to the coastal area; herring gulls showed an intermediate pattern. The diet of these sympatrically breeding gulls was analysed from pellet and faecal samples collected at two colonies. Considering biases in this method, the following components appeared to comprise the principal food for each species: black-headed gulls: bivalves, crustaceans; mew gulls: bivalves, polychaetes; herring gulls: bivalves, crustaceans; and lesser black-backed gulls: fish and crustaceans. Black-headed and mew gulls had much broader dietary niches than herring and lesser black-backed gulls. Based on spatial distribution, food choice and feeding habitat use, three types of foraging strategies are apparent: (1) black-headed and mew gulls forage both intertidally and on land, (2) herring gulls feed most frequently in the intertidal zone and (3) lesser black-backed gulls feed at sea. The foraging behaviour of these four species may well have influenced their current population trends in the study area.     

Spatio-temporal variations in the diet and stable isotope composition of the Argentine hake <Emphasis Type="Italic">Merluccius hubbsi</Emphasis> Marini, 1933 of the continental shelf of southeastern Brazil

The feeding ecology of Merluccius hubbsi was investigated in 2 regions of SE Brazil. The major food sources for the hakes were fish, crustaceans, and squid. In the upwelling system of Cabo Frio, the diet was very similar in the summers of 2001/2002 and spring 2002; fish were the most important prey followed by crustaceans. In Ubatuba, euphausiids were an important prey during the winter 2001 (100 m), while in the summer 2002, fish and amphipods predominated in the diet in the shallower site (40 m) and squid in the deeper site (100 m). The hakes showed temporal differences in stable isotope signatures in both regions, while C:N ratios varied only in Cabo Frio. δ¹⁵N and δ¹³C (bulk and corrected for lipid content) increased with fish length, which seems to be related to the increasing importance of fish and decreasing importance of euphausiids and amphipods in the diet of larger hakes. The mean trophic level of 3.7 for M. hubbsi was estimated using δ¹⁵N of bivalves as baseline and the fractionation of 3.4‰ between trophic levels.     

镉、汞、铅和石油烃复合污染对渤海湾常见渔业资源生物的影响初探(Effects of the Combined Pollution of Cd, Hg, Pb and Petroleum Hydrocarbons on Common Fishery Species in the Bohai Bay)

通过对1996～2005年渤海湾近岸海域海水镉、汞、铅和石油烃浓度变化的分析,发现海水中镉浓度呈明显上升趋势,汞、铅和石油烃则无明显变化趋势.加速生命试验法模型(Accelerated Life Testing model)的研究显示,1996～2005年渤海湾近岸海域海水镉、汞和铅平均浓度均已超过其对渤海湾常见渔业资源生物的安全浓度.镉、汞、铅和石油烃对生物的长期致死率鱼类分别为4.5%、16.3%、0.0%和12.0%,甲壳类为0.4%、7.9%、0.3%和6.6%,双壳类为10.5%、0.2%、0.2%和2.3%.效应加和模型(Independence Action model)的估算表明,在镉、汞、铅和石油烃组成的复合污染条件下,渤海湾常见鱼类、甲壳类和双壳类的长期死亡率分别为29.7%、14.6%和12.9%,其种群增长率分别降低约6.4%、14.6%和12.9%.与镉、汞、铅和石油烃单种污染物暴露相比,其复合污染导致的渤海湾常见渔业资源生物种群(鱼类、甲壳类和双壳类)增长率的降低更明显.因此,复合污染是导致渤海湾渔业资源衰退的重要因素。     

Effect of water extract of the bark of Buchanania lanzan linn. on behaviour and chromatophores of a fresh water fish,Labeo rohita

Fish exposed to 150 ppm and 250 ppm doses saparately, showed eratic swimming with hyper-excitability, spiralling, convulsion and mortality. However at 350 ppm dose fish became lethargic and steady at the bottom of aquarium. This behaviour appears to be due to sedative effects of fish implicating the phychoactive nature of the plant B. Ianzan. At 150 ppm to 350 ppm doses, fish scale changed from reticulate to punctate chromatophores; and treated fish when transferred to fresh water, were slowly regained to normal behaviour after 96 h exposure. Hence doses regaining from 150 ppm to 350 ppm is considered to be psychoative in nature. In higher doses 450 ppm and 550 ppm fish could survive only 76 h and 4.30 h respectively and then died indicating toxicity of plant for the said doses. It is found that scale present on its body is most suitable test system for the study of psychoactivity and toxicity of plant extracts on fish, Labeo rohita.     

Residues of PCDD,PCDF, and PCBs in some marine organisms in Lake Temsah,Ismailia, Egypt

Residues of PCDDs/F, non-ortho, mono-ortho PCBs, and other PCBs were monitored in the tissues of mullet fish, bolti fish, bivalves and crab taken from Lake Temsah, at Ismailia, Egypt.

Results showed that 2,3,7,8 Tetra CDD and 1,2,3,7,8 Penta CDD were the most frequently detected PCDD congeners. Similarly, 2,3,7,8 Tetra CDF, 1,2,3,7,8 Penta CDF and 2,3,4,7,8 Penta CDF were the most frequently detected PCDF congeners. No relationship was apparent between the concentrations of detected PCDDs congeners and the degree of chlorination, except with crab samples in which an increase in the chlorination coincided with a decrease in the concentrations of the congeners.

In PCDF congeners, detected residues have had a reversed relationship with chlorination increase. In PCDD congeners, Octa CDD had the highest detected concentrations in the two fish species, while in the bivalves and crab, 2,3,7,8 Tetra CDD had the highest concentrations. The mullet fish had the highest total PCDDs concentration, at 0.398?pg/g fresh weight, followed by crab at 0.395?pg/g fresh weight, then bivalves and bolti fish at 0.187 and 0.062?pg/g fresh weight, respectively. In all the examined organisms, the total concentrations of PCDFs were much higher than the total concentrations of the PCDD congeners. The WHO–TEQ values were 11.92, 39.12, 25, and 3.6?pg/g fresh weight, for mullet fish, bolti fish, bivlaves and crab, respectively. The concentration of the mono-ortho congeners CB 118 was the highest detected of all non-ortho and mono-ortho PCBs congeners, with values of 0.382, 0.022, 0.231 and 0.357?ng/g fresh weight, in mullet fish, bolti fish, bivalves and crab, respectively. The WHO–TEQ concentrations were 0.799, 0.003?pg/g fw, 0.05?pg/g fresh weight, 0.676?pg/g, and 0.799?pg/g fresh weight, for the same species, respectively. The total concentration of PCBs 28, 52, 95, 99, 101, 105, 110, 118, 138, 146, 149, 151, 153, 170, 177, 180, 187 were 6.86?ng/g fresh weight for mullet fish, 0.2?ng/g fresh weight, for bolti fish, 2.72?ng/g fresh weight for bivalves and 2.8?ng/g fresh weight for crab, respectively.     

Can bottom trawling indirectly diminish carrying capacity in a marine ecosystem?

Bottom trawling is associated with reduced biomass and production in the marine benthic community. Abundance of hard-bodied organisms such as bivalves, crustaceans and echinoderms typically declines in favour of soft-bodied opportunists such as polychaetes. Trawling effects vary with habitat; impact and recovery time are typically greater for more complex substrates/communities and those with lower rates of natural disturbance. Benthic organisms represent the prey base of a large component of the demersal fish assemblage. Hence, trawling-induced change in benthic community structure and function may exert an indirect effect on feeding success and growth of important commercially exploited fishes such as plaice Pleuronectes platessa. We present habitat-specific mixed effects models of plaice length as a function of age, bottom-trawling effort, population density and near-bottom temperature, with sampling year and area, and fish sex incorporated as random effects. Across an observed gradient of trawling effort in the Celtic Sea, plaice on gravel habitat showed significant declines in length at age while plaice on sand habitat showed significant increases in length at age. Contrasting trawling effects likely reflect dietary differences between habitats. Plaice on sand substrates are known to consume predominately polychaetes, which may proliferate at moderate trawling intensity in this habitat. Conversely, plaice on gravel substrates are reported to consume more of the fragile organisms such as echinoderms and bivalves that show marked declines with bottom trawling. An indirect effect of trawling on prey availability and growth of demersal fish has substantial implications for fisheries sustainability via reduced ecosystem carrying capacity and production of commercial fish.     

The Influence of Temperature and Salinity Upon the Acute Toxicity of Heavy Metals to the Banana Prawn (Penaeus merguiensis de Man)

Bioassays were conducted to determine the effects of temperature and salinity on the acute toxicity of mercury, copper, cadmium, zinc, nickel and lead to juvenile banana prawns (Penaeus merguiensis de Man). Tests were conducted at all combinations of 35, 30 and 20°C with 36 and 20° salinity over 96 h. The general rank order of metal toxicity was Hg > (Cu, Cd, Zn) > Ni > Pb. The toxicity of all metals increased with increased temperature. This was most noticeable in the high salinity treatments, particularly for copper and zinc. Salinity appeared to influence the toxicity of all metals tested although significant differences were only found for copper and lead at 20°C. At this temperature prawns were markedly more susceptible to both metals in low salinity sea water. The data are compared with lethal concentrations found for other crustaceans and are discussed in relation to existing water quality criteria.     

Acute toxicity of oil dispersants to marine fish larvae

The acute toxicities of several oil dispersants to the larvae of haddock, herring, lemon sole, pilchard, plaice and sole were examined, the type and aromatic content of the solvent being the main factors influencing the toxicity. Newer (second generation) dispersants had much lower toxicities. Ageing of dispersant solutions led to a decrease in toxicity, which could be related to loss of aromatic compounds from solution. Temperature and salinity had only slight influence on toxicity. For all dispersants, differences of susceptibility between species were less than differences at different ages within a species. The larvae of all species showed a similar susceptibility when newly hatched, and susceptibility increased throughout the yolk-sac stage. The transition period from yolk reserves to an external food supply was most critical, for once larvae had established feeding, resistance increased until metamorphosis. The dispersants appeared to act largely as physical toxins causing, initially at least, a reversible narcosis. The implications of the results are discussed in relation to the use of dispersants at sea.     

Identification of a sensitive index during fish bioassay of an azo dye methyl red (untreated and treated)

Acute and chronic toxicity of methyl red (untreated) was examined on a freshwater fish Poecilia reticulata, using indices viz; mortality, reduction in RBC counts and their morphological abnormality (poikilocytosis and anisocytosis). Similar studies (acute toxicity) were also made in physicochemically and biologically treated methyl red. Data comparison of these four indices revealed poikilocytosis as the most sensitive index, since it measured higher toxicity of methyl red when fish mortality was either minimum at its low concentration (5 ppm) during both acute and chronic toxicity or even nil in the biologically treated 100 ppm methyl red, during acute toxicity. Mortality was next to poikilocytosis though it ranked 1st at higher concentration of methyl red during acute toxicity. The reduction in RBC counts however, was found to be the most sensitive parameter only in case of prolonged exposure (4 weeks) to 5 ppm methyl red. Amongst the four indices used for quantifying toxicity; anisocytosis was found to be the least expressive. Based on these findings we recommend quantification of data on fish mortality and poikilocytosis during acute toxicity whereas reduction in RBC counts and poikilocytosis during chronic exposure to methyl red.     

Diets of four decapod crustaceans (Linuparus trigonus,Metanephrops andamanicus,M. australiensis and M. boschmai) from the continental shelf around Australia

Linuparus trigonus (Palinuridae) was collected from northeast Australia at depths of 220 to 300 m in the austral summer of 1985–1986 and its diet was analysed for diel feeding-periodicity and composition. The sex and size of the lobsters and the depth at which they were caught were recorded. About 35% of the foreguts were less than 10% full. L. trigonus appears to be a predator of slow-moving or nearsessile benthic invertebrates; its diet is mainly bivalves, gastropods, ophiuroids, crustaceans, polychaetes, and foraminiferans. Most dietary items differed significantly between the size classes of lobster. The frequency of crustacean remains increased with depth and more gastropods were consumed by lobsters caught at 260 m than at other depths. No significant periodicity in feeding was found for L. trigonus. The foreguts of three Metanephrops spp. (Nephropidae) collected from north-west Australia in August 1983 (M. andamanicus) and January/February 1984 (M. australiensis and M. boschmai) were nearly empty, and nearly half were less than 10% full. Fish, crustaceans and squids were the most common food items eaten. The main food items varied between the species: M. andamanicus ate nearly equal amounts of fish and crustaceans; M. australiensis ate chiefly crustaceans; M. boschmai mainly ate fish and seldom fed on squid. Metanephrops spp. appear to feed by attacking mobile animals and tearing off appendages or by scavenging.     

The toxicity of heavy metals to embryos of the American oyster Crassostrea virginica

The acute toxicity of 11 heavy metals to embryos of the American oyster Crassostrea virginica was studied and the concentrations at which 50% of the embryos did not develop were determined. The most toxic metals and their LC₅₀ values were mercury (0.0056 ppm), silver (0.0058 ppm), copper (0.103 ppm) and zinc (0.31 ppm). Those metals that were not as toxic and their LC₅₀ values were nickel (1.18 ppm), lead (2.45 ppm) and cadmium (3.80 ppm). Those metals that were relatively non-toxic and their LC₅₀ values were arsenic (7.5 ppm), chromium (10.3 ppm) and manganese (16.0 ppm). Aluminum was non-toxic at 7.5 ppm, the highest concentration tested.     

Effects of ocean acidification on invertebrate settlement at volcanic CO2 vents

We present the first study of the effects of ocean acidification on settlement of benthic invertebrates and microfauna. Artificial collectors were placed for 1 month along pH gradients at CO₂ vents off Ischia (Tyrrhenian Sea, Italy). Seventy-nine taxa were identified from six main taxonomic groups (foraminiferans, nematodes, polychaetes, molluscs, crustaceans and chaetognaths). Calcareous foraminiferans, serpulid polychaetes, gastropods and bivalves showed highly significant reductions in recruitment to the collectors as pCO₂ rose from normal (336–341 ppm, pH 8.09–8.15) to high levels (886–5,148 ppm) causing acidified conditions near the vents (pH 7.08–7.79). Only the syllid polychaete Syllis prolifera had higher abundances at the most acidified station, although a wide range of polychaetes and small crustaceans was able to settle and survive under these conditions. A few taxa (Amphiglena mediterranea, Leptochelia dubia, Caprella acanthifera) were particularly abundant at stations acidified by intermediate amounts of CO₂ (pH 7.41–7.99). These results show that increased levels of CO₂ can profoundly affect the settlement of a wide range of benthic organisms.     

Monitoring toxicity of an azo dye methyl red and a heavy metal Cu,using plant and animal bioassays

Toxicities of an azo dye methyl red and a heavy metal copper (Cu) were quantified, using growth and mortality as end points, in four plant species and three animal species by subjecting them to short-term (4 days for animals, 10 days for plants) static bioassays. Lemna aequinoctialis Welwitch (EC₅₀: 7–16 ppm) was found to be the most sensitive species for methyl red, Ceratophyllum demersum L. (EC₅₀: 25 ppm) and Lactuca sativa L. (EC₅₀: 56 ppm) were intermediate, while Oryza sativa L. shows reduction in seedling vigor (9–27%) of <50%, being the least sensitive amongst the tested plant species. Methyl red toxicity is almost 3–5-fold higher in growing medium (pH = 5.8–6.0), even at high nutrient levels, while Cu toxicity is higher in nutrient-poor alkaline medium at alkaline pH (8.3–8.7; EC₅₀: Ceratophyllum = 104–200 ppb; Lemna = 100–170 ppb) compared to nutrient-rich acidic medium (pH = 5.4–5.7; EC₅₀: Ceratophyllum = 2600–3175 ppb; Lemna = 4350–4715 ppb). Rice tolerance (EC₅₀: 6500 ppb) was found to be higher than hydrophytes while lettuce was most tolerant to Cu. Fish sensitivity toward the test chemicals was almost parallel to Ceratophyllum and Lemna [Gambusia affinis Baird and Gerard (LC₅₀: 250 ppb for Cu) and Poecilia reticulata Peters (LC₅₀: 24 ppm for methyl red)]. Similar to the plants, dye toxicity increased markedly (LC₅₀: 7 ppm) in the acidic medium (pH = 6.0). Amongst the tested organisms, Daphnia was found to be most sensitive to methyl red (EC₅₀: 6 ppm) while its sensitivity to Cu (EC₅₀: 230 ppb) was similar to hydrophytes and fish. Initially, the combination of dye and Cu (at their sublethal concentrations) had additive effects in duckweed, while dye concentration ruled afterward. These results indicate that hydrophytes and animals are equally sensitive toward the test chemicals. Dye toxicity in hydrophytes and fish was pH dependent, while in the case of Cu, it is related to the nutrient status of the growth medium of plants.     

Impact of malathion on the biochemical parameters of gobiid fish, Glossogobius giuris (Ham)

There is a dearth of information regarding the changes in heart muscle metabolites induced by pesticides. In the present study, the gobiid fish, Glossogobius giuris, was exposed to sub lethal concentrations of (0.05, 0.25 and 0.5 ppm) organophosphorus pesticide, malathion for short duration (24 to 96 hr). The cardiac muscles showed maximum depletion of glycogen and cholesterol content during 72 and 96 hr after treatment with 0.5 ppm malathion. Whereas a slight fluctuation of protein and glycogen content was observed in low concentration (0.05 ppm) of malathion. The levels of protein showed a significant decrease at high concentration (0.5 ppm) when treated for longer duration (96 hr). The present study reports metabolic dysfunction in response to malathion toxicity in the fish.     

基于物种敏感性分布的保护海水水生生物的石油烃急性毒性基准研究

溢油污染对水生生物的危害以及分散剂使用对原油毒性的影响一直是溢油应急响应及危害评估时关注的焦点。本研究收集筛选了基于标准测试方法的90组急性毒性数据(LC50/EC50),其中37组毒性数据来自15种油品的水容纳组分(water accommodated fraction,WAF),53组来自11种化学分散剂与15种油品的分散液(chemically dispersed water accommodated fraction,CEWAF),应用物种敏感性分布(species sensitivity distribution,SSD)方法推导了基于水生生物保护的石油烃总量(total petroleum hydrocarbon,TPH)的急性毒性基准值,同时还分析了分散剂和不同暴露方式对原油毒性的影响。结果显示,以名义浓度(nominal concentrations)所表示的毒性结果可能高估分散剂对原油毒性的影响,基于CEWAF和WAF的LC50/EC50所推导的有害浓度(HC5s)差异较小,计算出的保护水生生物TPH急性毒性基准值为0.38 mg·L-1(TPH);鱼类对原油污染的响应明显敏感于甲壳类;同时证明了SSD方法在溢油毒性评估及风险阈值推导中具有可行性和合理性。     

Trace metal pollution in aquatic sediments and some fish species from the Kwilu-Ngongo River,Democratic Republic of Congo (Bas-Congo)

In this study, the concentrations of some metals in sediments and consumable fish from the Kwilu Ngongo River, province of Bas-Congo, Democratic Republic of Congo, are investigated. The digested muscle tissue, whole fish, and river sediment samples were subjected to trace element analysis by inductively coupled plasma mass spectroscopy and by using an automatic mercury analyzer. The highest values of trace metals in fish muscle tissue were found for Cr, Cu, Pb and Hg, with maximum values of 8.6 (Cr), 15.7 (Cu), 6.0 (Pb) and 3.3 (Hg) mg kg^?1. These values are higher than maximum tolerable limits recommended by the European Commission Regulation for Food. The highest metal concentrations in sediments were 81 (Cr), 86 (Cu), 21 (Sb), 41 (Pb), and 0.8 (Hg) mg kg^?1. Sediment toxicity tests using benthic crustaceans (ostracods) revealed mortality rates of up to 30% after six days of exposure to the sediments near the sugarcane industry outlet pipe discharge. The contamination of the sediments and fishes by the elements and the bio-accumulation of mercury in fish most likely arise from the adjacent agricultural fields where intensive sugarcane cultivation since 1925 has probably contaminated the soils through the long-term use of fertilizers and pesticides.     

Characterization of arsenic content in marine organisms from temperate, tropical, and polar environments

Arsenic is a widely distributed element which occurs in several chemical forms in the marine environment. Inorganic arsenic mediates the most toxic effects and predominates in sea water and sediments, while organisms generally accumulate non-toxic organic forms to concentrations probably reflecting species-specific characteristics in arsenic metabolism. This work represents an additional contribution to our knowledge on natural levels and chemical speciation of arsenic in marine organisms; basal concentrations were characterized in several species (bivalves, crustaceans, and fishes) from different environments (polar, temperate, and tropical latitudes), and results revealed an elevated variability with values ranging from less than 5 to about 200 μg g^-1. No significant effects were observed as a function of the geographical area, with the only exception of crustaceans always showing more elevated arsenic concentrations in Mediterranean species (about 45-110 μg g^-1) compared with tropical species (lower than 30 μg g^-1). Chemical speciation of arsenic was investigated in representative species from the three studied taxa; the predominance of organic forms confirmed the general tendency of marine organisms to bioaccumulate non-toxic arsenic compounds, probably resulting from a detoxification pathway.     

铜对水生生物的毒性:类群特异性敏感度分析

铜的毒性因受多种环境因素(如温度、pH等)的影响,其水质基准和标准经历过多次修改。由于不同区系生物受生活环境等因素的影响,不同物种对铜的耐受性和敏感度上存在很大的差异。本文通过构建类群特异性敏感度分布,以及对10%安全浓度值(10%hazardous concentration,HC_(10))及其95%置信区间(95%confidence interval,95%CI)的比较,分析了铜对淡水和海水各类群的敏感度差异,以期为我国在制定相关水质基准的物种选择上提供参考。结果显示,淡水系统中藻类为对铜毒性最敏感类群,其次为甲壳类,软体动物类,鱼类,寡毛类,而昆虫类为对铜的最耐受类群。海水各类群对铜的敏感度顺序与淡水类似,只是在寡毛类和鱼类顺序上有所不同。相对于海洋物种,淡水水体生物总体上比海水中各相应类群生物对铜更为敏感。