Marthe Monique Gagnon

The value of stress protein 70 as an environmental biomarker of fish health under field conditions

Hsp70 protein in three tissue types (gill, liver, and muscle) from black bream (Acanthopagrus butcheri) collected in a highly variable estuarine environment was investigated to determine which tissue provides better intersite discrimination. The usefulness of hsp70 expression to identify anthropogenic stress under field conditions was evaluated. Intersite differences were detected in hsp70 levels in gill and white muscle of black bream while liver showed no spatial difference. There was high interfish variability in hsp70 levels in each tissue group. A post hoc power analysis of the datasets for each tissue found that in black bream, white muscle provided the best discriminatory power to elucidate spatial variability. Only 11 fish per site are required to identify significant intersite differences in white muscle whereas for gill and liver tissues 14 and 21 fish per site, respectively, would be required. Because of high intertissue and interindividual variability, field measurement of hsp70 should be complemented by evidence of changes in other biomarkers of fish health.

Trace metal incorporation in otoliths of pink snapper (Pagrus auratus) as an environmental monitor

Otolith metal concentrations may be related to the environmental exposure history of fish to contamination. Otoliths of pink snapper (Pagrus auratus) collected from the marine basin of Cockburn Sound and offshore near Rottnest Island were analysed by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to measure the concentrations of 11 trace metals. The following metals were investigated using their respective isotopes: aluminum (27Al), calcium (44Ca), manganese (55Mn), iron (57Fe), copper (65Cu), zinc (66Zn), strontium (88Sr), cadmium (111Cd), barium (138Ba), mercury (202Hg) and lead (208Pb). Significant differences in otolith metal concentrations were found between the sampling locations for Zn, Cd and Pb. These metals were significantly higher in the otolith edges of the pink snapper captured from the extensive industrial area bordering Cockburn Sound. Life history transects of Zn, Cd and Pb within otoliths of pink snapper sampled from Cockburn Sound typically showed temporal trends that may correspond to the movement of this fish species in and out of this contaminated area during the yearly spawning season.

Serum Sorbitol Dehydrogenase Activity as an Indicator of Chemically Induced Liver Damage in Black Bream (Acanthopagrus butcheri)

The value of serum sorbitol dehydrogenase (s-SDH) activity to diagnose chemically induced liver damage in the fish, black bream (Acanthopagrus butcheri), was assessed by intraperitoneal injection with pentachlorophenol sodium salt. Day 3 post-injection s-SDH activity levels were elevated in fish injected at the highest dosage (30 mg Kg−1) compared to control and other treatment groups. Control fish had s-SDH activity levels within the range of 15 to 88 mU mL−1 serum, while at the highest Na-PCP treatment s-SDH activity was 2.5 to 3.5 times higher on day 3 relative to control fish with levels returning to control levels by the 6th day following injection. An increase in the liver somatic index was not identified until day 6 post-injection and histological damage (hyperplasia) was not detected until the 9th day following injection in the high dosage treatment group. This study confirms that changes in s-SDH activity in black bream due to exposure to hepatotoxicants can be detected before physiological or hi...

Diuron increases spinal deformity in early-life-stage pink snapper Pagrus auratus

Polybrominated diphenyl ethers (PBDEs) and hydroxylated and methoxylated polybrominated and chlorinated analogues in the plasma of fish from the Detroit River. Environmental Science and Technology 39 (15), 5612–5619. Verreault, L., Dietz, R., Sonne, C., Gebbink, W.A., Shahmiri, S., Letcher, R.J., 2008. Comparative fate of organohalogen contaminants in two top carnivores in Greenland: captive sledge dogs and free-ranging polar bears. Comparative Biochemistry and Physiology Part C 147, 306–315. Ylitalo, G.M., Matkin, C.O., Buzitis, J., Krahn, M.M., Jones, L.L., Rowles, T., Stein, J.E., 2001. Influence of life-history parameters on organochlorine concentrations in free-ranging killer whales (Orcinus orca) from Prince William Sound, AK. Science of the Total Environment 281, 183–203.

Accumulation of cadmium in the otoliths and tissues of juvenile pink snapper (Pagrus auratus Forster) following dietary and waterborne exposure.

Laboratory experiments were conducted to examine if incorporation of Cd into the otoliths of juvenile pink snapper (Pagrus auratus Forster) was related to levels in the food or water. In the first experiment, fish were fed a regular diet (control group) or a Cd-contaminated diet (500mgCdkg(-1) or 1500mgCdkg(-1)) for 35days. In the second experiment, fish were exposed to waterborne Cd concentrations of <0.002microgL(-1) (control), 50microgL(-1), 100microgL(-1) and 150microgL(-1) for 35days. The sagittal otoliths were analysed using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Juvenile fish exposed to higher concentrations of waterborne or dietary Cd showed increased Cd levels in their otoliths. This study clearly demonstrated that both aqueous and dietary Cd exposures can result in Cd incorporation into the otoliths of pink snapper.

Biomarkers of exposure in fish inhabiting the Swan–Canning Estuary, Western Australia – a preliminary study

The estuarine portion of the Swan–Canning riversystem runs through the centre of Perth,Western Australias capital city, with apopulation of approximately 1.4 million people. Little is known about impact of chemicalsentering the estuary via road runoff andstormwater drains on biota inhabiting thesystem. Black bream (Acanthopagrusbutcheri) were collected from seven sites inthe Swan–Canning estuary during August andSeptember 2000, at the end of the winter (wet)season. Serum sorbitol dehydrogenase (s-SDH)was unaffected by the sex of the fish and nosignificant differences were observed betweenthe sites indicating that the measuredethoxyresorufin-O-deethylase (EROD)activity was not hindered by hepatic tissuedamage. The black bream were in an advancedstage of gonad maturation, which affected ERODhepatic activity with lower EROD activity infemale compared to male fish. EROD activityand bile metabolite levels were significantlyhigher at the site closest to the Perth CentralBusiness District, while most downstream sitewas the least impacted, which may be due totidal flushing of the lower estuary by marinewaters. The ratio of naphthalene-type tobenzo(a) pyrene (B(a)P)-typemetabolites suggests that the source ofpetroleum hydrocarbons within the river systemis a mixture polycyclic aromatic hydrocarbons(PAHs) from pyrolytic origin and from unburntfuels. Biomarker levels in the black breamindicate that major roads and drains aresignificant contributors of mixed functionoxygenase (MFO) inducing chemicals includingpolycyclic aromatic hydrocarbons (PAH) into theSwan–Canning estuary and that there is noupstream or downstream gradient in biomarkerresponse.

Metabolic disturbances in fish exposed to sodium pentachlorophenate (NaPCP) and 3,3',4,4',5-pentachlorobiphenyl (PCB126), individually or combined.

The Swan River Estuary is the recipient of multiple urban and agricultural contaminants which have the potential to induce liver detoxication enzymes as well as altering the metabolism of aquatic organisms. To test if altered liver metabolism would influence liver detoxication capacities, pink snapper (Pagrus auratus) were i.p. injected with peanut oil (controls), or pentachlorobiphenyl #126 (PCB126), with sodium pentachlorophenate (NaPCP), or PCB126+NaPCP. Relative to controls, ethoxyresorufin-O-deethylase (EROD) activity was induced in the PCB126 and PCB126+NaPCP fish, but not in the NaPCP group. In the liver, cytochrome c oxidase (CCO) activity was enhanced by the treatments while citrate synthase (CS) activity remained unchanged and lactate dehydrogenase (LDH) activity was increased in the NaPCP treatment only. The results suggest that liver CCO activity may be a suitable biomarker of effect following exposure to PCBs or phenolic compounds. In the white muscle, only the PCB126+NaPCP treatment enhanced CCO activity, with all other enzymatic activities remaining unchanged. It appears that the resilience to metabolic perturbations is greater for white muscle than for liver. Low serum sorbitol dehydrogenase (sSDH) activity and histopathology of the liver indicated no significant alteration of cellular structure, albeit the lipid droplet size was increased in the PCB126 and in the PCB126+NaPCP treatments. It is concluded that the hepatic metabolic changes correspond to histopathological observations, but an altered metabolic capacity do not influence the metabolism of xenobiotics by liver enzymes, as measured by EROD activity.

Hepatic Metabolism of Contaminants in the Terapontid Fish, Yellowtail Trumpeter (Amniataba caudavittata Richardson)

The yellowtail trumpeter (Amniataba caudavittata) is an estuarine‐dependent omnivorous fish found in the Swan‐Canning Estuary, Western Australia. Thirty five fish were injected with either the polycyclic aromatic hydrocarbon, benzo[a]pyrene (B[a]P), the synthetic flavenoid β‐naphthoflavone (BNF), or used as controls. The fish were then sampled at 3 and 7 days postinjection. Induction of the enzyme ethoxyresorufin O‐deethylase (EROD) activity was nonsignificant while ethoxycoumarin O‐deethylase (ECOD) activity induction differed amongst treatments. A high interindividual variability in the EROD activity was observed. The measurement of sorbitol dehydrogenase in the serum (s‐SDH) was elevated (BNF 2.2 times and B[a]P 3.2 times the control fish) demonstrating that liver cell damage had occurred. Increases in biliary metabolites of both B[a]P‐type and pyrene‐type (19 times and 3.4 times the controls respectively) indicated that detoxification of pyrene‐type compounds had taken place. Fish of the Terapontidae family, such as the yellowtail trumpeter, were found to be suitable for biomonitoring the health of the Swan‐Canning Estuary. A combination of ECOD activity, s‐SDH, and the measurement of biliary metabolites represents a suitable suite of biomarkers for environmental monitoring of the sublethal effects of PAH pollution in these fish.

An Assessment of the Effectiveness of High Definition Cameras as Remote Monitoring Tools for Dolphin Ecology Studies.

Research involving marine mammals often requires costly field programs. This paper assessed whether the benefits of using cameras outweighs the implications of having personnel performing marine mammal detection in the field. The efficacy of video and still cameras to detect Indo-Pacific bottlenose dolphins (Tursiops aduncus) in the Fremantle Harbour (Western Australia) was evaluated, with consideration on how environmental conditions affect detectability. The cameras were set on a tower in the Fremantle Port channel and videos were perused at 1.75 times the normal speed. Images from the cameras were used to estimate position of dolphins at the water’s surface. Dolphin detections ranged from 5.6 m to 463.3 m for the video camera, and from 10.8 m to 347.8 m for the still camera. Detection range showed to be satisfactory when compared to distances at which dolphins would be detected by field observers. The relative effect of environmental conditions on detectability was considered by fitting a Generalised Estimation Equations (GEEs) model with Beaufort, level of glare and their interactions as predictors and a temporal auto-correlation structure. The best fit model indicated level of glare had an effect, with more intense periods of glare corresponding to lower occurrences of observed dolphins. However this effect was not large (-0.264) and the parameter estimate was associated with a large standard error (0.113). The limited field of view was the main restraint in that cameras can be only applied to detections of animals observed rather than counts of individuals. However, the use of cameras was effective for long term monitoring of occurrence of dolphins, outweighing the costs and reducing the health and safety risks to field personal. This study showed that cameras could be effectively implemented onshore for research such as studying changes in habitat use in response to development and construction activities.

Field studies using fish biomarkers – How many fish are enough?

Significant efforts are invested in field studies using fish, and it is important to optimize the number of organisms collected to evaluate the possible impacts of contamination. This paper provides ecotoxicologists with the approximate numbers of fish needed to identify statistically significant differences among samples using physiological indices and biochemical markers of fish health. The numbers of fish to collect are reported for ethoxyresorufin-o-deethylase (EROD); ethoxycoumarin-o-deethylase (ECOD), serum sorbitol dehydrogenase (sSDH), stress proteins, gonadosomatic index, liver somatic index, condition factor, and biliary metabolites of polycyclic aromatic hydrocarbons. The number of fish to collect was as few as four for ECOD activity (with a power of 80%), but as high as 106 for CF (with a power of 95%). Achieving statistical significance between sites does not help in the interpretation of the biological significance of a parameter, but well-planned field samplings will maximize the chances of correctly identifying areas of concern.