No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Integration of multi-tissue PAH and PCB burdens with biomarker activity in three coastal shark species from the northwestern Gulf of Mexico
... For instance, Lyons and Wynne-Edwards (2018) found that PCBs intrauterine exposure affects embryonic growth in male embryos of as well as osmotic homeostasis in Urobatis helleri (Lyons and Wynne-Edwards, 2021). Studies addressing oxidative status and biotransformation effects of prenatal exposure are notably lacking, albeit oxidative damage, and xenobiotics metabolism responses have been related to contaminant levels in adult elasmobranchs worldwide (Barrera-Garcia et al., 2013;Lyons et al., 2014;Walker et al., 2014;Alves et al., 2016;Cullen et al., 2019;Wosnick et al., 2021;Rodrigues et al., 2022;Alves et al., 2022). Considering that embryonic stages are more vulnerable to contaminants (Petersen and Kristensen, 1998;Jezierska et al., 2009), it is likely that intrauterine exposure might lead to physiological consequences. ...
... We previously found a lower maternal transfer of higher ringed PAHs , culminating with the lack of transfer of the same elements not detected herein. Despite this, the individual PAHs concentration found in P. horkelii embryos is lower than most of reports for elasmobranchs (Oliva et al., 2017;Cullen et al., 2019;Hernout et al., 2020), including adult guitarfishes of the same species (Martins et al., Fig. 1. Relationship between yolk-sac mass and total length of embryos of Pseudobatos horkelii. ...
... Alves et al. (2016), analyzing multiple contaminants, did not report GST associations with other biomarkers or contaminants, suggesting that GST might not be a suitable biomarker in elasmobranchs. In contrast, GST induction was detected in sharks exposed to high levels of PAHs (Cullen et al., 2019). From a comparative point of view, GST activity was lower in benthic batoids when compared to sharks exposed to equal concentrations of arene and alkene substrates (James et al., 1979), so lower GST activity might be inherent to benthic elasmobranchs like guitarfishes (Solé et al., 2009). ...
Coastal elasmobranchs are vulnerable to chemicals mostly due to their k-strategic life history characteristics and high trophic positions. Embryos might be particularly exposed through the maternal offloading of contaminants, possibly leading to disruptions during critical developmental phases. Yet, knowledge on biochemical outcomes of prenatal exposure in elasmobranchs is notably limited. Therefore, we aimed to investigate the effects of prenatal exposure to contaminants in embryos of the critically endangered Brazilian guitarfish, Pseudobatos horkelii. Polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), pharmaceuticals and personal care products, and metals were determined in embryos. Additionally, glutathione S-transferase activity (GST), glutathione (GSH), and metallothionein levels (MT) were analyzed. Finally, lipid peroxidation levels (LPO) and protein carbonyl groups (PCO) were assessed. Embryonic exposure depended on yolk consumption, which was conspicuous in earlier development. We observed a dilution effect of contaminants levels, potentially related to biotransformation of these compounds throughout the embryonic development. Nevertheless, GST was not correlated to contaminant concentrations. The multivariate relationship between antioxidant components (GSH and GST) and LPO and PCO was negative, suggesting the lack of efficient defense of these biomarkers in early development, leading to oxidative damage. In this context, our results indicate that prenatal exposure to contaminants might impact the redox status in embryos of P. horkelii, leading to oxidative damage. Furthermore, metal concentrations influenced MT levels, suggesting this as a potential detoxification pathway in this species.
... Indeed, such analytical approaches determined that PAH contamination in coral reef fishes from the South China Sea originated from biomass combustion, petroleum sources, and vehicular emissions (Li et al., 2019). Similar to those associated with antioxidant roles with metal exposure, enzymes that have been specifically identified for tracking PAH exposure because of their elimination pathways include ethoxyresorufin-O-deethylase (EROD) and GST (Cullen et al., 2019;King et al., 2005). It has also been determined that liver burdens are indicative of acute exposure to PAHs because the tissue is highly dynamic when compared to muscle. ...
... Trophic ecology is key as well, with sharks prone to bioaccumulation and biomagnification since they occupy high trophic levels in their ecosystems. Although Cullen et al. (2019) measured higher than expected PAH accumulation in the liver and muscle samples from several shark species, they also noted that diet, niche partitioning, and life history characteristics, including those spanning ontogeny, affect PAH accumulation. ...
... PAH exposure also alters growth and has a suite of other physiological effects as demonstrated in salmonids (e.g., Meador et al., 2006), cod (Sørensen et al., 2019), haddock (Meier et al., 2010;Sørhus et al., 2016), herring (Incardona et al., 2012) and mahi mahi (Mager et al., 2017). Other studies have indicated that PAH exposure and accumulation in fishes can cause genotoxicity (and associated carcinogenesis), as well as endocrine and metabolic disruption (reviewed in Cullen et al., 2019) and enhanced photo-toxicity upon exposure to ultra-violet (UV) radiation (Aranguren-Abadía et al., 2022). While the interaction with PAH and UV exposure has been thoroughly demonstrated in cod (Aranguren-Abadía et al., 2022) and mahi mahi (Alloy et al., 2016), given the proximity of coral reefs to UV radiation and the surge of studies documenting adverse effects of PAH and UV exposure on corals (Overmans et al., 2018), it follows that this combination of stressors will continue to increase in relevance in the Anthropocene. ...
Coral reef fishes and the ecosystems they support represent some of the most biodiverse and productive ecosystems on the planet yet are under threat as they face dramatic increases in multiple, interacting stressors that are largely intensified by anthropogenic influences, such as climate change. Coral reef fishes have been the topic of 875 studies between 1979 and 2020 examining physiological responses to various abiotic and biotic stressors. Here, we highlight the current state of knowledge regarding coral reef fishes' responses to eight key abiotic stressors (i.e., pollutants, temperature, hypoxia and ocean deoxygenation, pH/CO2, noise, salinity, pressure/depth, and turbidity) and four key biotic stressors (i.e., prey abundance, predator threats, parasites, and disease) and discuss stressors that have been examined in combination. We conclude with a horizon scan to discuss acclimation and adaptation, technological advances, knowledge gaps, and the future of physiological research on coral reef fishes. As we proceed through this new epoch, the Anthropocene, it is critical that the scientific and general communities work to recognize the issues that various habitats and ecosystems, such as coral reefs and the fishes that depend on and support them, are facing so that mitigation strategies can be implemented to protect biodiversity and ecosystem health.
... In Carcharhiniformes from Galveston Bay (Texas, Gulf of Mexico, USA), total hepatic PAH concentrations were significantly higher in Blacktip (2.1 μg g -1 w.w.) and Bonnethead (Sphyrna tiburo, 2.2 μg g -1 w.w.) sharks compared to Bull sharks (C. leucas, 1.6 μg g -1 w.w.), although no significant differences for muscle tissue were detected among species (Cullen et al., 2019). ...
... Furthermore, PAHs levels detected in at Sabine Lake (Texas, Gulf of Mexico, USA) were similar to those detected in C. leucas individuals sampled in Galveston Bay (110.39 km away), pointing to chronic exposure in both locations and Bull shark inability to eliminate PAHs at faster rates than their absorption (Cullen et al. 2019). Martins et al. (2020) evaluated the tissue distribution of 18 PAHs in the Brazilian guitarfish (Pseudobatos horkelii) in the Southwest Atlantic, reporting mean concentrations ranging from 0.83 to 2.13 μg g -1 w.w. in blood and muscle samples. ...
... Biochemical assessments (i.e., EROD and GST activities) were also carried out in the sharks from Galveston Bay (Cullen et al., 2019), and only weak correlations with no possible explanations were noted. Dibenzo[a,h]anthracene and indeno[1,2,3, c-d]pyrene, however, displayed a positive relationship to EROD activity. ...
... In Carcharhiniformes from Galveston Bay (Texas, Gulf of Mexico, USA), total hepatic PAH concentrations were significantly higher in Blacktip (2.1 μg g -1 w.w.) and Bonnethead (Sphyrna tiburo, 2.2 μg g -1 w.w.) sharks compared to Bull sharks (C. leucas, 1.6 μg g -1 w.w.), although no significant differences for muscle tissue were detected among species (Cullen et al., 2019). ...
... Furthermore, PAHs levels detected in at Sabine Lake (Texas, Gulf of Mexico, USA) were similar to those detected in C. leucas individuals sampled in Galveston Bay (110.39 km away), pointing to chronic exposure in both locations and Bull shark inability to eliminate PAHs at faster rates than their absorption (Cullen et al. 2019). Martins et al. (2020) evaluated the tissue distribution of 18 PAHs in the Brazilian guitarfish (Pseudobatos horkelii) in the Southwest Atlantic, reporting mean concentrations ranging from 0.83 to 2.13 μg g -1 w.w. in blood and muscle samples. ...
... Biochemical assessments (i.e., EROD and GST activities) were also carried out in the sharks from Galveston Bay (Cullen et al., 2019), and only weak correlations with no possible explanations were noted. Dibenzo [a,h]anthracene and indeno[1,2,3, c-d]pyrene, however, displayed a positive relationship to EROD activity. ...
Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous organic compounds in the marine environment, originating mainly from anthropogenic sources. Due to their physico-chemical properties and ability to bioaccumulate in living organisms, PAHs are of great ecotoxicological concern, and their carcinogenic, and genotoxic properties make these compounds particularly harmful to exposed organisms. In this context, marine fauna assessments are paramount to estimate PAH environmental bioavailability, biochemical effects, as well et al. 38 as potential ecological effects. Evaluations in marine organisms, such as bony fish, are readily available. Studies concerning sharks and batoids (elasmobranchs), however, are still scarce, which is interesting as this group is an important part of marine trophic network interactions and highly threatened by anthropogenic activities, including chemical contamination. In this context, this chapter will discuss PAH exposure and their associated effects in elasmobranchs. Furthermore, ensuing ecological concerns and public health implications due to contaminated elasmobranch meat consumption shall also be reflected upon.
... The second way of assessing cyt P450 in fish is to determine its catalytic activity using the enzymatic activity of ethoxyresorufin-Odeethylase (EROD) as a proxy (Whyte et al., 2000), an approach supported by the good correlations generally observed between CYP1A protein levels and EROD activity (Sarasquete and Segner, 2000). There is evidence that the presence of pollutants affects EROD activity in a small shark species (Fuentes-Rios et al., 2005a, b), as well as in larger species (Cullen et al., 2019), and even in a species of ray (Lyons et al., 2014). These are all very different animals, possessing specific feeding and habitat preferences (Compagno et al., 2005), reinforcing the assumption that the CYP1A and EROD levels may be used as biomarkers of pollution effects in elasmobranchs. ...
... Scyliorhinus canicula and Galeus melastomus) possess lower activities than teleosts (Gorbi et al., 2004;Solé et al., 2010a). Differences among species of elasmobranchs have also been observed, with Sphyrna tiburo showing greater activities than Carcharhinus leucas and Carcharhinus limbatus (Cullen et al., 2019). Finally, even among individuals from the same species of elasmobranch, EROD activities may vary due to attributes such as sex (Lyons et al., 2014). ...
... been successfully used as a biomarker of pollution effects in several teleosts (Santana et al., 2018), providing justification for scientists to test if the same can be true with elasmobranchs. Despite indications that GST in elasmobranchs may be lower when compared with teleosts (Gorbi et al., 2004), significant correlations between this biomarker and concentrations of POPs have already been described in 3 species of sharks (Cullen et al., 2019). One study also found the levels of GST to be positively correlated with concentrations of As in liver of P. glauca individuals (Barrera-García et al., 2013). ...
Bioindicator species are increasingly valuable in environmental pollution monitoring, and elasmobranch species include many suitable candidates for that role. By measuring contaminants and employing biomarkers of effect in relevant elasmobranch species, scientists may gain important insights about the impacts of pollution in marine ecosystems. This review compiles biomarkers applied in elasmobranchs to assess the effect of pollutants (e.g., metals, persistent organic pollutants, and plastics), and the environmental changes induced by anthropogenic activities (e.g., shifts in marine temperature, pH, and oxygenation). Over 30 biomarkers measured in more than 12 species were examined, including biotransformation biomarkers (e.g., cytochrome P450 1A), oxidative stress-related biomarkers (e.g., superoxide anion, lipid peroxidation, catalase, and vitamins), stress proteins (e.g., heat shock protein 70), reproductive and endocrine biomarkers (e.g., vitellogenin), osmoregulation biomarkers (e.g., trimethylamine N-oxide, Na⁺/K⁺-ATPase, and plasma ions), energetic and neurotoxic biomarkers (e.g., lactate dehydrogenase, lactate, and cholinesterases), and histopathological and morphologic biomarkers (e.g., tissue lesions and gross indices).
... Previous studies have shown that sharks may easily bioaccumulate and biomagnify pollutants such as PAHs, PCBs, heavy metals, etc., and may pose negative impacts on them (Ma et al., 2014;Peng et al., 2014;Cullen et al., 2019;Rodríguez-Gutiérrez et al., 2020;Salvo et al., 2020). Silky sharks mostly prey in the upper layers of coastal areas mainly on fish, cephalopods, and crustaceans (Cabrera-Chávez-Costa et al., 2010). ...
... leucas) (1330 ± 164 ng/g ww), blacktip (C. limbatus) (1150 ± 75.7 ng/g ww), and bonnethead sharks (Sphyrna tiburo) (1080 ± 44.2 ng/g ww) collected from the northwestern Gulf of Mexico (Cullen et al., 2019). However, in all muscle tissue samples, the concentration of BaP (CF3: 2.6 ng/g ww and CF8: 7.2 ng/g ww) and the sum of four PAHs (BaA, CH, BaP, and BbF) in two samples were higher than the maximum allowable level set by EU regulation, according to which the BaP in fish muscle was 2.0 ng/g ww, and the sum of the four PAHs in fish muscle is 12.0 ng/g ww (European Union, 2011). ...
... The Spearman's rank correlation coefficient between the PAHs burden of the muscle and the morphometry of silky sharks is shown in Table 4. Spearman correlation analysis performed using the data of all silky sharks (n = 11) showed that there were no significant correlations between the weight, total length, and K value of silky sharks and the PAHs burden of their muscles (Table 4). Cullen et al. (2019) reported that the PAHs in bull (C. leucas), blacktip (C. ...
The silky shark (Carcharhinus falciformis) is the most abundant and widely distributed shark species in the marine system of tropical regions. However, it appears that there is limited information on USEPA 16 polycyclic aromatic hydrocarbons (PAHs) concentration in silky shark muscle tissue, which has together with the lack of a health risk assessment of human consumption of silky shark filets. The potential toxicity of PAHs in muscles of silky sharks and cancer and non-cancer risk of consumers were assessed. Results showed that the total PAHs (TPAHs) concentration in the muscle tissue of silky sharks was between 62 and 657 ng/g ww, with an average of 234 ± 221 (mean ± standard deviation) ng/g ww, and can be considered as minimally to moderately contaminated level. Naphthalene (NA), phenanthrene (PH), and fluoranthene (FLU) are the most abundant PAHs in silky sharks muscle tissue, accounting for 38.6%, 11.0%, and 19.0% of TPAHs, respectively. The average values of toxic benzo[a]pyrene (BaP) equivalent (TEQcarc) and toxic dioxin equivalent (TEQfish) of PAHs equal to the potency of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in silky shark muscle are 13.5 ± 16.4 ng BaP/g ww and 34.1 ± 77.4 pg TCDD/g ww, respectively, and they showed a good linear relationship (r = 0.928; p < 0.001). The TEQcarc of silky sharks muscle is higher than USEPA's screening value of PAHs of 3.2 ng BaP/g ww for adults, indicating a potential negative impact on public health. The calculated hazard index (HI) of PAHs is less than 1, suggesting that residents eating silky shark muscle will not expect to cause significant non-cancer risk. However, the incremental lifetime cancer risk (ILCR) of BaP as 10.6-26.3% and 8.2-32.4% in males and females, respectively, may pose a significant cancer risk. In general, children and the elderly have relatively higher risks, as well as males have a higher cancer and non-cancer risk than females.
... The resulting residue was reconstituted into 200 μL of ACN and transferred to a 200 μL glass insert. All samples were then stored at − 20 • C for 1 h to precipitate lipids and other aqueous debris (Hong et al., 2004;Cullen et al., 2019). Following freezing, a 50 μL aliquot of the lipid-free supernatant was removed and transferred to a 2 mL glass amber vial. ...
... Blanks were run before and after analysis to rule out possible contamination. Details on method optimization are presented elsewhere (Cullen et al., 2019). For brevity, matrix spike/recovery trials yielded an average % recovery of 95-100% for acenaphthene and benzo (a)pyrene, and 71-92% for PCBs 101 and 138. ...
... This level is starkly contrasted to the high lipid content of hepatic tissues in apex predators, such as sharks (~4× higher, 51-63% of ww) from the GoM (Cullen et al., 2019). Despite this marked difference in lipid levels, the average ∑ PAHs for each taxa of deep-sea megafauna in this study ranged from 2518 to 17,175 ng g − 1 ww, which is ~2× to ~8× of those reported in sharks from the Gulf of Mexico (Cullen et al., 2019). However, the high end of this range is occupied by those taxa with low representation in terms of sample size. ...
There is a paucity of information on the levels of PAHs and PCBs in the deep-sea (≥200 m). In this study, the body-burdens of 16 PAHs and 29 PCBs were measured in: Actinaria (sea anemones), Holothuroidea (sea cucumber), Pennatulacea (sea pens), and Crinoidea (sea lilies) in the deep Gulf of Mexico. All epibenthic species were collected at depths of approximately 2000 m. The PAH and PCB congener profile displayed a similar pattern of bioaccumulation across all four taxa. The high molecular weight PAH, dibenz[a,h]anthracene, was the most abundant PAH in all organisms, ranging from 36 to 53% of sum total PAHs. PCBs 101 and 138 exhibited the highest levels at 20–25% of total congener concentrations in all taxa. The exposure to PAHs and PCBs is likely attributed to contaminated particulate organic matter that is consumed by the deposit and filter feeding epibenthic megafauna sampled in this study.
... All PCBs are identified according to the IUPAC numbering system. The commercial vendors used to procure individual PAH and PCB standards are detailed in Cullen et al. (2019) . ...
... Furthermore, a recent study by Cullen et al. (2019) monitored the same profile of PAHs (as reported in this study) in juvenile bull sharks opportunistically sampled from around Galveston Bay and other nearshore sites. In agreement with current observations for bull sharks from Sabine Lake, Cullen et al. (2019) also reported a predominance of HMW PAHs such as dibenzo [a,h]anthracene (DahA) and indeno [123cd]pyrene (IcdP) in bull shark livers. ...
... Furthermore, a recent study by Cullen et al. (2019) monitored the same profile of PAHs (as reported in this study) in juvenile bull sharks opportunistically sampled from around Galveston Bay and other nearshore sites. In agreement with current observations for bull sharks from Sabine Lake, Cullen et al. (2019) also reported a predominance of HMW PAHs such as dibenzo [a,h]anthracene (DahA) and indeno [123cd]pyrene (IcdP) in bull shark livers. This observation was also shown to be consistent for the two other shark species sampled, namely blacktip ( Carcharhinus limbatus ) and bonnethead ( Sphyrna tiburo ) sharks ( Cullen et al., 2019 ). ...
This study investigated whether the composition of fatty acids in hepatic tissue of four fish species from Sabine Lake (TX), influenced hepatic body-burdens of pollutants. The multivariate correlations between hepatic body-burdens of sixteen polycyclic aromatic hydrocarbons (PAHs) and twenty-nine polychlorinated biphenyls (PCBs), with thirty-seven fatty acids was studied. The trophic ecology of fish was determined using stomach content analysis and by comparing characteristic fatty acid profiles. The fish species studied included: bull shark (Carcharhinus leucas), alligator gar (Atractosteus spatula), red drum (Sciaenops ocellatus), and gafftopsail catfish (Bagre marinus). Assessment of fish stomach contents demarcated catfish and red drum (mainly invertebrate diet) vs. alligator gars and bull sharks (mainly teleost diet). Elevated levels (45× higher) of nervonic acid (24:1n9) also placed the trophic ecology of catfish and red drum closer to the base of the marine/estuarine food web of Sabine Lake, as compared to alligator gars and bull sharks. PAH profiles showed a predominance of low molecular weight PAHs (≤3 aromatic rings) in catfish, red drum and alligator gars. Bull sharks exhibited the highest levels for select high molecular weight PAHs (≥ 4 aromatic rings). The overall predominance of low molecular weight PAHs indicated exposure to mainly petrogenic sources of PAHs. Bull sharks and alligator gars also exhibited the highest body-burdens of PCBs. The risk assessment of dioxin-like PCBs showed median toxic equivalent (TEQ) values in bull sharks to be the highest, and above the upper toxicity thresholds for adverse effects in fish and aquatic mammals. The multivariate correlational analysis of pollutant body-burdens and fatty acid levels showed no clear correlation of the pollutants with any particular type of fatty acid (unsaturated vs. saturated, short-chain vs. very-long chain). This result indicates that pollutant bioaccumulation was not associative with the specific fatty acid composition of lipids in the fish from Sabine Lake.
... However, the majority of the studies are directed at the quantification of these pollutants in different tissues, especially in muscle, the main product derived from fishing for these animals (Barreto et al., 2017;Fowler et al., 2021). In addition, the liver, a large organ and rich in lipids, provides a significant compartment of up to 20 % of the body mass for the accumulation of lipophilic pollutants and constitutes the main organ involved in the metal detoxification process (Cullen et al., 2019;Hauser-Davis et al., 2021). Thus, previous studies aimed to understand if the molecular effects of pollutants on these animals are still scarce, and usually, are aimed at the analysis of biochemical markers such as ethoxyresorufin-O-deethlyase (EROD), intracellular reactive oxygen species (ROS), glutathione S-transferase (GST), lactate dehydrogenase (LDH), metallothionein, and serum markers (Cullen et al., 2019;Wosnick et al., 2021a;Wosnick et al., 2021b;Hauser-Davis et al., 2021). ...
... In addition, the liver, a large organ and rich in lipids, provides a significant compartment of up to 20 % of the body mass for the accumulation of lipophilic pollutants and constitutes the main organ involved in the metal detoxification process (Cullen et al., 2019;Hauser-Davis et al., 2021). Thus, previous studies aimed to understand if the molecular effects of pollutants on these animals are still scarce, and usually, are aimed at the analysis of biochemical markers such as ethoxyresorufin-O-deethlyase (EROD), intracellular reactive oxygen species (ROS), glutathione S-transferase (GST), lactate dehydrogenase (LDH), metallothionein, and serum markers (Cullen et al., 2019;Wosnick et al., 2021a;Wosnick et al., 2021b;Hauser-Davis et al., 2021). ...
Elasmobranchs can bioaccumulate and biomagnify pollutants. However, few studies are directed to the effects of pollutants on the health of these animals, and in most cases, are limited to the analysis of biochemical markers. Thus, the incidence of genomic damage among shark species inhabiting a protected ocean island in the South Atlantic was investigated in association with the analysis of pollutants in seawater sample. High levels of genomic damage were identified, especially in Negaprion brevirostris and Galeocerdo cuvier, in addition to interspecific variations that may be related to characteristics such as animal size, metabolism and habits. High concentrations of Surfactants were observed in seawater sample, in addition to low concentrations of Cadmium, Lead, Copper, Chromium, Zinc, Manganese, and Mercury. The results evidenced the potential of shark species as a bioindicator of environmental quality and allowed assessing the anthropic impact on the archipelago, which currently drives its economy through tourism.
... Discriminant SMAM may be also combined to UMAM. In a recent study, Cullen et al., (2019) combined PCA and a partial redundancy analysis (pRDA) to study POP contamination in shark species from the northwestern Gulf of Mexico. pRDA aims to summarize linear relationship between components of response variables and explanatory variables in removing the effect of one or more explanatory variables with strong effect (Anderson, 2017). ...
... pRDA aims to summarize linear relationship between components of response variables and explanatory variables in removing the effect of one or more explanatory variables with strong effect (Anderson, 2017). Cullen et al. (2019) evaluated, through pRDA, correlations between POP congeners and biomarker responses (ethoxyresorufin-O-deethlyase, EROD and glutathione S-transferase, GST) while limiting the effect of interspecific variability of POP concentrations between the 3 studied shark species (Carcharhinus leucas, Carcharhinus limbatus, Sphyrna tiburo). This method may be particularly useful to highlight weakly pronounced relationships, especially when the sample sets are heterogeneous. ...
Thousands of chemicals are potentially contaminating the environment and food resources, covering a wide spectrum of molecular structures, physico-chemical properties, sources, environmental behavior and toxic pro-files. Beyond the description of the individual chemicals, characterizing contaminant mixtures in related matrices has become a major challenge in ecological and human health risk assessments. Continuous analytical de-velopments, in the fields of targeted (TA) and non-targeted analysis (NTA), have resulted in ever larger sets of data on associated chemical profiles. More than ever, the implementation of advanced data analysis strategies is essential to elucidate profiles and extract new knowledge from these large data sets. Specifically focusing on the data analysis step, this review summarizes the recent progress in integrating data analysis tools into TA and NTA workflows to address the challenging characterization of chemical mixtures in environmental and food matrices. As fish matrices are relevant in both aquatic pollution and consumer exposure perspectives, fish was chosen as the main theme to illustrate this review, although the present document is equally relevant to other food and environmental matrices.
The key features of TA and NTA data sets were reviewed to illustrate the challenges associated with their analysis. Advanced filtering strategies to mine NTA data sets are presented, with a particular focus on chemical filters and discriminant analysis. Further, the applications of supervised and unsupervised multivariate analysis methods to characterize exposure to chemical mixtures, and their associated challenges, is discussed
... A mixture of deuterated standards naphthalene-d 8 , phenanthrene-d 10 , and perylene-d 12 , was added using a microsyringe, prior to extraction [35,53]. The PAHs were extracted following established protocols [54]. Briefly, 3 mL of 1:1 v/v hexane:ethyl acetate was added to the tube, then placed in a Fisherbrand TM Bead Mill 4 Homogenizer (Fisher Scientific, Waltham, MA, USA) and homogenized at a processing power of 150 g for 2 min. ...
... The PAHs were resolved using a 30-m long Agilent DB-5MS column. The operating conditions are specified elsewhere [53,54]. Quantification of the PAHs was determined by the response factors determined from a 10-point calibration curve. ...
Marine snow was implicated in the transport of oil to the seafloor during the Deepwater Horizon oil spill, but the exact processes remain controversial. In this study, we investigated the concentrations and distributions of the 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs) in marine snow aggregates collected during a mesocosm experiment. Seawater only, oil in a water accommodated fraction (WAF), and Corexit-enhanced WAF (DCEWAF) were incubated for 16 d. Both WAF and DCEWAF aggregates were enriched in heavy molecular weight PAHs but depleted in naphthalene. DCEWAF aggregates had 2.6 times more total 16 PAHs than the WAF (20.5 vs. 7.8 µg/g). Aggregates in the WAF and DCEWAF incorporated 4.4% and 19.3%, respectively of the total PAHs in the mesocosm tanks. Our results revealed that marine snow sorbed and scavenged heavy molecular weight PAHs in the water column and the application of Corexit enhanced the incorporation of PAHs into the sinking aggregates.
... whereby W is mass (kg) and T L is total length (cm) (Gilliers et al., 2004). Muscle was chosen as a good integrator of organic contaminants over time due to its slower turnover rate compared to liver (Cullen et al., 2019). White muscle was collected between the dorsal fins of adults. ...
... PCBs (Table S2) and, to a lesser extent, in DDTs (Table S3), indicating that these banned compounds are still used in some countries in the Southern Hemisphere, probably for mosquito control (van den Berg et al., 2017). Sharks caught in the Northern Hemisphere showed 10 to 1000 times higher PCB concentrations than sharks caught in RUN, with the exception of individuals caught near Portugal and in the Northeast Pacific Ocean, which showed similar concentrations to bull sharks from RUN (Alves et al., 2016;Boldrocchi et al., 2020;Cullen et al., 2019;Johnson-Restrepo et al., 2005;Lee et al., 2015;Storelli et al., 2003). Mean DDT concentrations in RUN sharks were similar to those in various shark species caught in the Northeast Pacific Ocean, with the exception of oceanic whitetip sharks (Carcharhinus longimanus), characterized by 100-fold lower DDT concentrations (Table S3; Lee et al., 2015). ...
The contamination of tiger sharks (Galeocerdo cuvier) and bull sharks (Carcharhinus leucas) by legacy persistent organic pollutants (POPs) and emerging organic contaminants was investigated in specimens from Reunion Island (Southwest Indian Ocean) in 2018 and 2019. Contamination levels were determined in the muscle of adult individuals of both sexes in relation to biological and trophic parameters. Maternal transfer was additionally investigated in one set of embryos in each species. Polychlorinated biphenyl (PCB), organochlorinated pesticide (OCP) and perfluoroalkylated substance (PFAS) concentrations were 2597 ± 2969, 785 ± 966 and 267 ± 194 pg g-1 ww, respectively, in bull sharks, and 339 ± 270, 1025 ± 946 and 144 ± 53 pg g-1 ww in tiger sharks. The results highlighted higher PCB contamination, and by the heavier congeners, in adult bull sharks versus tiger sharks. The significant differences found in PCB profiles and concentrations suggest that the two species are exposed to different contamination sources. As bull sharks rely on a more coastal habitat for feeding, their higher contamination by PCBs suggests the occurrence of local PCB sources. DDT concentrations were similar in both species, suggesting a more homogeneous contamination on the scale of the Southwest Indian Ocean. Female bull sharks showed lower OCP and PCB concentrations than males, while this trend was not observed in tiger sharks. The ratio of chlorinated contaminants in muscle between the mother and her embryos was related to molecule hydrophobicity in bull shark but not in tiger shark, suggesting that shark mode of gestation, known to be different in the two species, is a key driver of organic contaminant maternal transfer. Finally, the results show that organic contaminant levels in the studied species were lower than those of other shark species in the Southern Hemisphere, related to the limited urbanization and industrialization of Reunion Island.
... Similar research has been conducted and reported in various fish species exposed to pesticides, POPs and heavy metals Lu et al., 2010). The induction of GST activity has also been confirmed in bull (Carcharhinus leucas), blacktip (Carcharhinus limbatus), and bonnethead (Sphyrna tiburo) sharks from Galveston Bay, which is lightly polluted by polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) (Cullen et al., 2019). ...
... Detailed studies have provided evidence that many species exhibit an increased TBARS level following stress produced by some xenobiotics (Zhang and Wang, 2003). Because different stressors target different biomarkers, more researchers have noted the importance of using a suite of biomarkers in aquatic field research to monitor and assess environmental risk under exposure to pollutants, which takes full advantage of the different biomarkers and provides a reliable interpretation of ecotoxicological examinations Lu et al., 2010;Cullen et al., 2019). Because the levels far exceeded the safe limit, the accumulation and distribution of Cd in aquatic animals was used to discuss the metabolism and transfer of pollutants in organisms. ...
Combined with sediment pollutant analysis, the gastropod Cipangopaludina cahayensis was chosen as an indicator organism to evaluate the environmental behavior of trace metals and the aquatic ecological risk that they present in a backwater area of Xian'nv Lake. Based on hydrological characteristics, 24 sampling sites representing the main stream (MS), tributaries (TR), lake area (LA) and lake tributaries (LT) were collected. The results revealed that cadmium (Cd) was the main pollutant and that it significantly accumulated in sediments of the research area. Based on the pollutant concentrations, the degree of Cd pollution was ranked in the following order: LA > MS > TR > LT. Several intersections between the rivers and Xian'nv Lake, including LA1, LA7 and LA 10, were observed to have higher Cd deposition. There was a significant difference in the spatial distribution of pollutants, which resulted in a higher accumulation of trace metals in the backwater area and its tributary. The Cd content in the visceral sac of C. cahayensis was positively correlated with the concentration of heavy metals in the sediment. The response of multiple antioxidant biomarkers, including superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST), as well as the glutathione (GSH) content and the level of by-products of lipid peroxidation (TBARS), in C. cahayensis revealed a potential relationship to the environmental behavior of the pollutants. By combining the different biomarkers responses, the integrated biomarker response index (IBR) corresponded well with the pollution distribution characteristics in different areas.
... Available information regarding the bioaccumulation of pollutants in elasmobranchs is currently limited to either specific locations of the world or to a restricted number of species [26,33,34]. Despite sharks are not being considered a popular source of fish meat [35], several shark species are targeted by fisheries to satisfy market demands for food consumption [36,37], thus raising public health concerns about the chemical contamination in elasmobranch tissues [38,39]. ...
Environmental pollution, particularly in the marine environment, has become a significant concern due to the increasing presence of pollutants and their adverse effects on ecosystems and human health. This study focuses on the bioaccumulation of trace elements in the muscle tissue of the blackmouth catshark (Galeus melastomus) from different areas in the Mediterranean Sea. Trace elements are of interest due to their persistence, toxicity, and potential for bioaccumulation. This research aims to assess the distribution and accumulation of trace elements in the muscle tissue of G. melastomus and investigate their potential impact on the deep-sea environment of the Mediterranean. The focused areas include the Ligurian Sea, the northern and central Tyrrhenian Sea, the southern Tyrrhenian Sea, the Ionian Sea, the Pantelleria Waters, and the Gela Waters. Samples were collected following established protocols, and trace element analysis was conducted using inductively coupled plasma mass spectrometry. The study provides data on the concentrations of 17 trace elements, namely aluminum, arsenic, cadmium, cobalt, copper, manganese, molybdenum, nickel, zinc, selenium, strontium, lead, chromium, iron, barium, bismuth, and uranium. The findings contribute to a better understanding of trace element bioaccumulation patterns in elasmobranch species, specifically G. melastomus, and highlight the potential risks associated with chemical contamination in the Mediterranean Sea. This research emphasizes the importance of studying the impacts of pollutants on marine organisms, particularly those occupying key ecological roles, like sharks, to support effective conservation and management strategies.
... Differences between liver and muscle burdens were only observed for Σ 9 PBDEs in S. guggenheim towards liver samples (t = 26.25; p = 0.030), whereas Σ 18 PAHs levels were similar in muscle and liver samples of all species, as observed previously in other elasmobranch species (Al-Hassan et al., 2000;Cullen et al., 2019;Martins et al., 2020). The differences regarding flame retardants might be attributed to differences in lipid content in these tissues, which was statistically higher in liver samples of all species (F Tissue = 160.3, ...
The present study aimed to determine persistent organic pollutants (POPs) and contaminants of emerging concern in endangered angelshark and guitarfish species from southeastern Brazil, and to investigate potential impacts of these compounds on morphometric indexes. Pesticides of emerging concern, pharmaceutical and personal care products (PPCPs), polycyclic aromatic hydrocarbons (PAHs), and polybrominated diphenyl ethers (PBDEs) were determined in hepatic and muscular tissues of Pseudobatos horkelii, P. percellens, Squatina guggenheim, and Zapteryx brevirostris obtained from artisanal and industrial fisheries operating in southeastern Brazil. Accumulation profiles and effects of contaminants on condition factor and hepatosomatic index were investigated. No differences were detected regarding species contaminant concentration, potentially due to similarities in habits, occurrence and trophic position shared by guitarfishes and angelsharks. Polycyclic aromatic hydrocarbons (23.2-495.3 ng g -1), and PPCPs such as diclofenac (<LOQ - 448.4 ng g-1) and methylparaben (<LOQ - 645.5 ng g-1) presented the highest concentrations, regardless of the species. Effects of elasmobranch size were not significant on contaminant levels, indicating the lack of bioaccumulation over time. We suggest that the exposure to contaminants in elasmobranchs inhabiting this region is highly dependent on the economic activities and high urban development in southeastern Brazil. Regarding potential impacts of such exposure, the condition factor was only negatively influenced by PBDEs concentrations, whereas the hepatosomatic index was not influenced by any contaminant. Despite this, our results indicate that guitarfishes and angelsharks are exposed to POPs and contaminants of emerging concern potentially toxic to aquatic organisms. In this context, more refined biomarkers should be used to predict potential impacts of these contaminants on elasmobranch's health.
... Field studies have shown that PAHs dilute with increasing food-chain steps in some ecosystems (Goutte et al., 2020;Wan et al., 2007) and potentially biomagnify in others (Froehner et al., 2011), with higher accumulation in apex marine predators (Cullen et al., 2019) and at higher trophic niches in lakes (Qadeer et al., 2019). As foundation species, corals play a crucial role in several reef food-chains. ...
Exposure from the dissolved-phase and through food-chains contributes to bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) in organisms such as fishes and copepods. However, very few studies have studied the accumulation of PAHs in corals. Information on dietary uptake contribution to PAHs accumulation in corals is especially limited. Here, we used Cavity-Ring-Down Spectroscopy (CRDS) to investigate the uptake rates and accumulation of a¹³C-labeled PAH, phenanthrene, in Acropora millepora corals over 14 days. Our experiment involved three treatments representing exposure levels of increasing food-chain length. In Level W, corals were exposed to ¹³C-phenanthrene directly dissolved in seawater. In Level 1 representing herbivory, Dunaliella salina microalgal culture pre-exposed to ¹³C-phenanthrene for 48 h was added to the coral treatments. In Level 2 representing predation, corals were provided a diet of copepod (Parvocalanus crassirostris) nauplii fed on D. salina pre-exposed to ¹³C-phenanthrene. Bioconcentration factors (BCF) and bioaccumulation factors (BAF) were calculated as appropriate for all organisms, and biomagnification factors (BMF) were calculated for A. millepora. We found that while phenanthrene uptake rates were not significantly different for the treatments, the accumulated concentration in corals was significantly higher in Level W (33.5 ± 2.83 mg kg⁻¹) than in Level 1 (27.55 ± 2.77 mg kg⁻¹) and Level 2 (29.36 ± 3.84 mg kg⁻¹). Coral log BAF values increased with food-chain length; Level 2 log BAF (6.45) was higher than Level W log BCF (4.18) and Level 1 log BAF (4.5). Coral BMF was also higher for Level 2 than for Level 1. Exposure to dissolved or diet-bound phenanthrene had no significant effect on the coral symbionts’ photosynthetic efficiency (Fv/Fm) as monitored by pulse-amplitude-modulation (PAM) fluorometry, indicating the PAH can be accumulated without toxic effects to their Photosystem II. Our study highlights the critical role of dietary exposure for pollutant accumulation in corals.
... Evidently, most of the uses of this biomarker tool goes to laboratorial assessment of biotic and abiotic factors, but a big share of studies account for the impacts of global changes on wildlife, with applicability in fishes (e.g., [66][67][68]), birds (e.g., [69,70]), turtles (e.g., [71,72]), or terrestrial and marine mammals (e.g., [73,74]), to name a few. The use of biomarkers is not limited to the realm of environmental sciences, that is a fact, and is (and should be) used increasingly to understand mechanisms that can lead to a better commercial use of organisms. ...
Endpoints assessed at the population or community level are most often the result of the sum of effects on individuals, arising from the effects at the cellular and molecular levels. Within this framework, these lower biological level endpoints are more responsive at an early stage of exposure, making them potential toolboxes to be used as early-warning markers to address stress. Given this, by linking responses and understanding organisms’ metabolism and physiology, the possibilities for the use of biomarkers in stress biology are vast. Here, biomarker comprehensive examples are given to enlighten the need to link levels of biological organization, and their usefulness for a myriad of fields and applications is presented and discussed.
... According to Zhou et al. (2008), biomonitoring reveals the integrated effects of the pollutants on the organisms by way of subtle biological changes that are not only sensitive due to the rapid onset of biological response but are also realized at contaminant levels that may be below detection limits due to chronic exposure to low doses. As a result, the bioaccumulation levels and responses in organisms such as algae, zooplankton, crustaceans, mollusks, fish, amphibians, and even marine mammals have been studied in aquatic and marine systems (Zhou et al., 2008;Cullen et al., 2019;Liu et al., 2019). ...
... According to Zhou et al. (2008), biomonitoring reveals the integrated effects of the pollutants on the organisms by way of subtle biological changes that are not only sensitive due to the rapid onset of biological response but are also realized at contaminant levels that may be below detection limits due to chronic exposure to low doses. As a result, the bioaccumulation levels and responses in organisms such as algae, zooplankton, crustaceans, mollusks, fish, amphibians, and even marine mammals have been studied in aquatic and marine systems (Zhou et al., 2008;Cullen et al., 2019;Liu et al., 2019). ...
... However, it can reflect the identity of the compounds that are contributing most to liver OCPs accumulation, and it is useful to evaluate the risk in humans associated to its consumption (Boldrocchi et al., 2019;Gelsleichter et al., 2005;Lyons et al., 2021). Additionally, it is a good indicator of the chronic exposure to organic contaminants, given it is a metabolically inert tissue whose lipid content does not fluctuate based on corporal condition and it has a slow turnover rate compared to the liver (Chynel et al., 2021;Cullen et al., 2019;Speers-Roesch and Treberg, 2010). ...
Despite the intensive use of organochlorine pesticides (OCPs) in the proximity of the Gulf of California, there is no information regarding their levels in predatory shark species, which could be exposed to relatively high concentrations. In this area, neonates and juveniles of the critically endangered scalloped hammerhead Sphyrna lewini are caught for consumption, so the examination of the accumulation of OCPs is necessary for future conservation, as well as to assess the exposure to humans. Levels and accumulation patterns of 29 OCPs were analyzed in the liver and muscle of 20 immature scalloped hammerheads. Twenty-three compounds were detected in liver and 17 OCPs were found in muscle. In the latter tissue, only p,p′-DDE presented concentrations above the detection limit in all samples (0.59 ± 0.21 ng/g w.w.), while in the liver, DDTs were also the main group of pesticides (215 ± 317 ng/g w.w.), followed by ∑Chlordanes > ∑Chlorobenzenes > Mirex > HCBD > Others. One of the two analyzed neonates presented high concentrations of OCPs in the liver (1830 ng/g w.w.), attributed to a bioamplification process. No differences in accumulation of OCPs were found between juveniles of both sexes, where an increase in the concentration of various compounds related with size and age was observed. Additionally, juveniles under 2 years of age may undergo a growth dilution process. Our results suggest that the consumption of this species does not imply risks to human health (chronic or carcinogenic effects) associated with OCPs. Likewise, we recommend further monitoring due to the possible recent inputs of some OCPs (e.g. dicofol, median of ratio o, p′-DDT/p, p′-DDT = 0.7) into the environment.
... According to Zhou et al. (2008), biomonitoring reveals the integrated effects of the pollutants on the organisms by way of subtle biological changes that are not only sensitive due to the rapid onset of biological response but are also realized at contaminant levels that may be below detection limits due to chronic exposure to low doses. As a result, the bioaccumulation levels and responses in organisms such as algae, zooplankton, crustaceans, mollusks, fish, amphibians, and even marine mammals have been studied in aquatic and marine systems (Zhou et al., 2008;Cullen et al., 2019;Liu et al., 2019). ...
In the past decade, the Deepwater Horizon oil spill triggered a spike in investigatory effort on the effects of crude oil chemicals, most notably polycyclic aromatic hydrocarbons (PAHs), on marine organisms and ecosystems. Oysters, susceptible to both waterborne and sediment-bound contaminants due to their filter-feeding and sessile nature, have become of great interest among scientists as both a bioindicator and model organism for research on environmental stressors. It has been shown in many parts of the world that PAHs readily bioaccumulate in the soft tissues of oysters. Subsequent experiments have highlighted the negative effects associated with exposure to PAHs including the upregulation of antioxidant and detoxifying gene transcripts and enzyme activities such as Superoxide dismutase, Cytochrome P450 enzymes, and Glutathione S-transferase, reduction in DNA integrity, increased infection prevalence, and reduced and abnormal larval growth. Much of these effects could be attributed to either oxidative damage, or a reallocation of energy away from critical biological processes such as reproduction and calcification toward health maintenance. Additional abiotic stressors including increased temperature, reduced salinity, and reduced pH may change how the oyster responds to environmental contaminants and may compound the negative effects of PAH exposure. The negative effects of acidification and longer-term salinity changes appear to add onto that of PAH toxicity, while shorter-term salinity changes may induce mechanisms that reduce PAH exposure. Elevated temperatures, on the other hand, cause such large physiological effects on their own that additional PAH exposure either fails to cause any significant effects or that the effects have little discernable pattern. In this review, the oyster is recognized as a model organism for the study of negative anthropogenic impacts on the environment, and the effects of various environmental stressors on the oyster model are compared, while synergistic effects of these stressors to PAH exposure are considered. Lastly, the understudied effects of PAH photo-toxicity on oysters reveals drastic increases to the toxicity of PAHs via photooxidation and the formation of quinones. The consequences of the interaction between local and global environmental stressors thus provide a glimpse into the differential response to anthropogenic impacts across regions of the world.
... The change in the perception of sharks, the rapid loss of elasmobranch species, and the destructive impacts of human activities, recently increased the interest in shark ecotoxicology (Tiktak et al., 2020;Boldrocchi et al., 2020a;Gelsleichter et al., 2020;Chynel et al., 2021). Nevertheless, available information regarding the bioaccumulation of pollutants in elasmobranchs is still scarce at present and limited to specific parts of the world or to a restricted number of species (Cullen et al., 2019;Boldrocchi et al., 2019). Moreover, most studies tend to focus on one or two species only (e.g. ...
We provided the first multi-species study investigating the presence and organotropism of trace elements in three tissues of 12 elasmobranch species. Shark species showed comparable TE loads, although milk sharks and juvenile scalloped hammerhead sharks exhibited the highest Cd and Hg levels, respectively. Fins accumulated higher levels of Pb, Co, and Cr; muscles higher V, As, and Hg; livers higher Se and Cd levels. The organotropism of TEs calls for cautious when choosing a tissue to be sampled since certain tissues, like fin clips, do not provide reliable surrogate for the internal loads of some TEs. Strong correlations between essential and toxic TEs indicated detoxification mechanisms, while the TMF provided evidence for Hg, As and Se biomagnification along the food-web.
Considering the difficulties in assessing elasmobranchs contamination from different areas, the proposed multi-species approach represents a valuable way to estimate the species-specific accumulation and transfer of pollutants in sharks.
... Moreover, as recently reviewed by Consales and Marsili [86], the biomarker approach has been utilized for assessing the conservation status of Chondrichthyans, including nearthreatened, vulnerable, and endangered species. The biomarkers utilized included biomarkers of organic chemical pollutant detoxification, antioxidant-and oxidative-stress-related responses, neurotoxicity, vitellogenin, and zona radiata protein, a sensitive biomarker for environmental estrogen exposure [87][88][89][90][91][92][93]. ...
Marine biodiversity is threatened by several anthropogenic pressures. Pollution deriving from the discharge of chemical contaminants in the sea represents one of the main threats to the marine environment, influencing the health of organisms, their ability to recover their homeostatic status, and in turn endangering biodiversity. Molecular and cellular responses to chemical pollutants, known as biomarkers, are effect-based methodologies useful for detecting exposure and for assessing the effects of pollutants on biota in environmental monitoring. The present review analyzes and discusses the recent literature on the use of biomarkers in the framework of biodiversity conservation. The study shows that pollution biomarkers can be useful tools for monitoring and assessment of pollution threat to marine biodiversity, both in the environmental quality monitoring of protected areas and the assessment of the health status of species at risk. Moreover, key areas of the research that need further development are suggested, such as the development of omics-based biomarkers specifically addressed to conservation purposes and their validation in the field, the extension of the biomarker study to a wider number of endangered species, and the development of organic guidelines for the application of the biomarker approach in support to conservation policies and management.
... As such, potential PCB contaminant impacts on stingrays appear to not exert their effects equally between the sexes or across the life stages. This work extends our understanding of the implicated impacts of contaminant exposure on a model elasmobranch system using physiological biomarkers, and joins mounting evidence that environmental PCB exposure is likely not physiologically inert in elasmobranchs (Frantz 2014;Sawyna et al. 2017;Cullen et al. 2019) and may impose additional metabolic costs. ...
Organic contaminants are known to affect a suite of physiological processes across vertebrate clades. However, despite their ancient lineage and important roles in maintaining healthy ecosystems, elasmobranchs (sharks, skates, and rays) are understudied with regard to sublethal effects of contaminant exposure on metabolic processes. Perturbations resulting from contaminant exposure can divert energy away from maintaining physiological homeostasis, particularly during energetically challenging life stages, such as pregnancy and embryonic development. Using the round stingray ( Urobatis halleri ) as a model elasmobranch species, we captured adult males and pregnant females (matrotrophic histotrophy) and their embryos from two populations differing in their environmental exposure to organic contaminants (primarily polychlorinated biphenyls (PCBs)). Pregnant females from the PCB-exposed population experienced significant decreases from early- to late-pregnancy in tissue mass and quality not seen in reference females. PCB-exposed pregnant females also failed to maintain plasma urea concentrations as pregnancy progressed, which was accompanied by a loss in muscle protein content. Despite the energetic demands of late-term pregnancy, females had significantly greater liver lipid content than reproductively inactive adult males. PCB-exposed adult males also had high metabolic capacity (i.e., enzyme activity) for most substrate groupings of all sex-site groups, suggesting that males may be even more negatively impacted by contaminant exposure than pregnant females. Evidence that in utero exposure to PCBs via maternal offloading impairs embryo outcomes is accumulating. Embryos from the PCB-contaminated site had lower tissue quality measures and indications that sex-based differences were manifesting in utero as males had higher metabolic capacities than females. This study indicates that accumulated PCB contaminants are not physiologically inert in the stingray.
... Even naturally occurring contaminants such as PAHs and heavy metals, which have been made more bioavailable by human activities, are known to be important stress factors for marine organisms (Marsili et al. 2014(Marsili et al. , 2016Scheuhammer et al. 2015;Santana et al. 2018;Cunningham et al. 2019;Lee et al. 2019). Furthermore, most studies have demonstrated the existence of pollutants in Chondrichthyans and their environments (Gelsleichter & Walker 2010), but few have examined the impact and effects of chemicals on these organisms (Fuentes-Rios et al. 2005;Solé et al. 2010aSolé et al. , 2010bBarrera-García et al. 2012, 2013Vélez-Alavez et al. 2013;Alves et al. 2016;Marsili et al. 2016;Fossi et al. 2017;Cullen et al. 2019;Lyons & Wynne-Edwards 2019;Ehnert-Russo & Gelsleichter 2020). ...
Cartilaginous fish include sharks, rays, skates, sawfish, and chimaeras. Their habitat ranges from shallow coastal waters to deep ocean floors, estuarine areas as well as rivers and inland waters. Overfishing is considered to be the main threat to their existence, but there are many more stressors that these species face. Pollution is an issue that concerns aquatic organisms at every level, and Chondrichthyans are no exception. Here, we looked at their IUCN Red List assessment, and noticed a lack of information regarding anthropogenic contamination for these species. Out of 1124 cartilaginous fish species assessed, only 17 Selachimorpha and 32 Batoidea species were considered to be facing a “pollution threat”; in most cases, the threat was assigned not from direct ecotoxicological studies of the specimens, but because the species inhabited areas likely to be contaminated. An update on the conservation status of these species is urgently needed. Further, there is a fundamental need to study the effects of contaminants on Chondrichthyans as they play a key role in aquatic ecosystems.
... On the other hand, high molecular (HMW) PAHs with higher K ow have higher depuration rate (Baumard et al., 1998b;Keshavarzifard et al., 2017d;Keshavarzifard et al., 2017b;Logan, 2007;Bandowe et al., 2014). Given long half-lives and high lipophilic characteristics of PAHs, they could be available to be accumulated by exposed aquatic species and biomagnified along food chain (Keshavarzifard et al., 2017d;Keshavarzifard et al., 2017b;Cullen et al., 2019), thereby presenting a risk to living organisms. The concentrations and bioavailability of contaminants as well as feeding behavior, trophic level, time of exposure and physiology can influence the accumulation of contaminants in living organisms in the aquatic ecosystem. ...
The distribution and sources of PAHs in jinga shrimp (Metapenaeus affinis), and human health risks due to consumption was evaluated in collected samples from the Musa Bay, Persian Gulf. The total concentration of PAHs (∑16PAHs) ranged from 10 to 144 μg kg⁻¹ dry weight, indicating low to moderate level of pollution. The PAHs were dominated by three- (41%) and two-ring (38%) compounds. Source identification analyses indicated the PAH pollution mostly originated from petroleum inputs. A preliminary evaluation of human health risk using chronic daily intake, hazard index, benzo[a]pyrene-equivalent (BaPeq) concentration (PEC) as well as the incremental life cancer risk and non-cancer risk assessment suggest low potential health risk for consumers of the Metapenaeus affinis. However, the results indicate minimal risks associated with the intake of PAHs via shrimp consumption, but long-term monitoring is required to evaluate the changes in ecological and human health impacts of contaminants in the region.
Main finding
PAHs in Metapenaeus affinis from Musa bay, which influenced by anthropogenic activities were low to moderate level of pollution. Human health risk indicates low potential health risk for consumers.
... Such affinities may expose tiger sharks to blowouts similar to Deepwater Horizon, which impacted surface and bottom waters of the north-central GoM region where we documented significant core habitat use [73]. Uptake and trophic transfer of petroleum-based pollutants, which accumulate in sharks [74,75] and are at significantly higher levels in sediments adjacent to platforms [76], needs further research in order to clarify the potential impacts of these anthropogenic activities on tiger shark health and biology. ...
The tiger shark (Galeocerdo cuvier) is globally distributed with established coastal and open-ocean movement patterns in many portions of its range. While all life stages of tiger sharks are known to occur in the Gulf of Mexico (GoM), variability in habitat use and movement patterns over ontogeny have never been quantified in this large marine ecosystem. To address this data gap we fitted 56 tiger sharks with Smart Position and Temperature transmitting tags between 2010 and 2018 and examined seasonal and spatial distribution patterns across the GoM. Additionally, we analyzed overlap of core habitats (i.e., 50% kernel density estimates) among individuals relative to large benthic features (oil and gas platforms, natural banks, bathymetric breaks). Our analyses revealed significant ontogenetic and seasonal differences in distribution patterns as well as across-shelf (i.e., regional) and sex-linked variability in movement rates. Presumably sub-adult and adult sharks achieved significantly higher movement rates and used off-shelf deeper habitats at greater proportions than juvenile sharks, particularly during the fall and winter seasons. Further, female maximum rate of movement was higher than males when accounting for size. Additionally, we found evidence of core regions encompassing the National Oceanographic and Atmospheric Administration designated Habitat Areas of Particular Concern (i.e., shelf-edge banks) during cooler months, particularly by females, as well as 2,504 oil and gas platforms. These data provide a baseline for future assessments of environmental impacts, such as climate variability or oil spills, on tiger shark movements and distribution in the region. Future research may benefit from combining alternative tracking tools, such as acoustic telemetry and genetic approaches, which can facilitate long-term assessment of the species’ movement dynamics and better elucidate the ecological significance of the core habitats identified here.
The synthesis and solvatochromic behavior of pyrimidine based Schiff-base (PYPH) were studied to develop a fluorescent chemo sensor for the detection of Hg²⁺ in aqueous solution. The characterization of PYPH was investigated on the basis of UV–vis, FTIR, ¹H-NMR and mass spectral data. PYPH displays selective fluorescent turn-off response to Hg²⁺ in aqueous solution. The sensitivity and selectivity of PYPH toward Hg²⁺ among different metal ions was examined by absorption, fluorescence, ¹H-NMR and mass spectral studies. Binding stoichiometry (2:1) has been confirmed by a Job’s plot, HRMS spectral studies and ¹H-NMR analysis. A low detection limit was 4.2 × 10⁻⁶ M for Hg²⁺. Ground state geometry of PYPH has been optimized using density functional theory (DFT). These results demonstrate that PYPH has promise to detect Hg²⁺ ion in environmental analysis systems.
Maternal transfer of contaminants is an important route of exposure for many species during embryonic development, which might compromise the organism throughout its life cycle. Here, we report the maternal offloading of polycyclic aromatic hydrocarbons (PAHs) in an elasmobranch, the Brazilian guitarfish Pseudobatos horkelii. Eighteen PAHs were determined by gas chromatography in maternal liver and uterine content (uterine eggs and early-stage development embryos) samples to determine the maternal transfer rate. The mean rate of PAHs offloaded to the offspring was of 13%, with high variability among individual congener transfer (0.7–29.9%) and benzo[b]fluoranthene attaining the highest maternal transfer rates. Differential transfer rates were attributed to physicochemical proprieties of each compound, with low molecular level PAHs presenting the highest rates. A depuration mechanism in which females decrease their maternal transfer rate as a function of size, related to consecutive reproductive cycles was not properly observed in this study. From a conservation perspective, these results indicate that elasmobranchs embryos of an endangered species can be exposed to PAHs during their development and, considering the possible harmful effects of these compounds to other early life stage organisms, deleterious effects could be a possibility, although this was not analyzed herein.
This review covers selected 2019 articles on the biological effects of pollutants, including human physical disturbances, on marine and estuarine plants, animals, ecosystems and habitats. The review, based largely on journal articles, covers field and laboratory measurement activities (bioaccumulation of contaminants, field assessment surveys, toxicity testing and biomarkers) as well as pollution issues of current interest including endocrine disrupters, emerging contaminants, wastewater discharges, marine debris, dredging and disposal etc. Special emphasis is placed on effects of oil spills and marine debris due largely to the 2010 Deepwater Horizon oil blowout in the Gulf of Mexico and proliferation of data on the assimilation and effects of marine debris microparticulates. Several topical areas reviewed in the past (e.g. mass mortalities ocean acidification) were dropped this year. The focus of this review is on effects, not on pollutant sources, chemistry, fate or transport. There is considerable overlap across subject areas (e.g. some bioaccumulation data may be appear in other topical categories such as effects of wastewater discharges, or biomarker studies appearing in oil toxicity literature). Therefore, we strongly urge readers to use keyword searching of the text and references to locate related but distributed information. Although nearly 400 papers are cited, these now represent a fraction of the literature on these subjects. Use this review mainly as a starting point. And please consult the original papers before citing them.
Elasmobranchs are particularly prone to accumulating contaminants due to their life history patterns and relatively high trophic position. However, several compounds, especially contaminants of emerging concern, have still not been well studied in this group. Here, we aimed to determine the occurrence and concentrations of several inorganic and organic contaminants in different tissues of the Brazilian guitarfish Pseudobatos horkelii. This species is a critically endangered species, endemic from the Southwest Atlantic which uses southern Brazilian waters as a nursery habitat. Polycyclic aromatic hydrocarbons (PAHs), emerging pesticides, pharmaceutical and personal care products (PPCPs) and trace metals were determined in five biological tissues in order to assess the accumulation and organotropism of these compounds. Except for chlorothalonil and triclosan, all compounds were detected in, at least, one tissue, mostly in liver samples. All compounds differed among tissues, with liver presenting the higher concentrations of several contaminants, followed by muscle and gills. PAHs and PPCPs were the most detected analytes and presented the highest concentrations among tissues. Diclofenac levels were determined, for the first time in elasmobranchs, and were relatively high, when compared to other fishes. Finally, relatively high concentrations of PAHs, dichlofluanid and octocrylene in muscle might be suggestive of chronic exposure, presenting also human health implications. Regarding trace metals, contrary to most elasmobranch studies, Hg levels were low in all tissues, whereas Cd and Pb here higher in liver, and gills and blood samples, respectively. Our results indicate that P. horkelii is exposed to several organic and inorganic which might affect this species in a long-term scale. Concerning the determination of emerging contaminants, it is likely that other elasmobranchs are also exposed to these compounds and special attention should be given to this issue in order to predict future effects on this group.
The way an animal utilizes and stores energy directly affects its ability to perform essential life functions (e.g. foraging, migration, reproduction), with implications for its health and fitness; therefore, individual variation in energy storage and metabolism within a population leads to intra-population variation in individual fitness and survival. Consequently, understanding the factors that contribute to variation in energy storage and metabolism within a population can aid in identifying factors that influence that population’s fitness. Compared to other taxa, there has been relatively little research to investigate the factors that govern variation in elasmobranch energy use and storage, particularly in wild populations. Furthermore, there has been almost no research conducted to explore how urbanization, a growing threat to marine ecosystems and organisms, affects elasmobranch energy storage and metabolism and, ultimately, their health and fitness. To address this knowledge gap, morphological (i.e. body condition) and biochemical (i.e. plasma cholesterol, free fatty acid, triglyceride, and ketone body concentrations) metrics related to energy storage and utilization were measured for 118 wild-sampled south Florida nurse sharks (Ginglymostoma cirratum). Statistical analyses were performed to identify any correlations between metrics and explore ontogenetic, sexual, seasonal, and spatial variation in body condition and plasma metabolite concentrations within the population. Results demonstrated that several metrics can be significantly linearly correlated with one another, but these relationships are highly dependent on nurse shark life stage and sex. The mean plasma metabolite concentrations for immature, mature female, and mature male nurse sharks was not significantly different; however, mature female nurse sharks had significantly higher body condition than mature male sharks. Further analysis revealed that this difference is driven by seasonal variation in mature female body condition, likely related to the accumulation of energy stores prior to reproduction. Significant seasonal variation also occurred in plasma concentrations of β-hydroxybutyric acid for mature male nurse sharks, possibly related to energetically exhausting mating activity during the wet season. Significant spatial variation occurred in the plasma concentrations of both triglycerides and free fatty acids for immature nurse sharks. Immature nurse sharks sampled within the more urbanized Metropolitan zone had higher mean triglyceride concentrations, and lower mean free fatty acid concentrations, than their conspecifics sampled within the relatively more natural National Park zone; this may imply that nurse sharks in the Metropolitan zone are feeding more, or more frequently, than nurse sharks in the National Park zone. The results of this thesis contribute to the growing knowledge base on energy storage and metabolism in wild-sampled elasmobranchs, as well as provide the first exploration of variation in elasmobranch body condition and plasma metabolites relative to urbanization, an anthropogenic threat with the capacity to influence elasmobranch fitness and survival.
The purification of homogeneous glutathione S-transferases B and C from rat liver is described. Kinetic and physical properties of these enzymes are compared with those of homogeneous transferases A and E. The letter designations for the transferases are based on the reverse order of elution from carboxymethylcellulose, the purification step in which the transferases are separated from each other. Transferase B was purified on the basis of its ability to conjugate iodomethane with glutathione, whereas transferase C was purified on the basis of conjugation with 1,2-dichloro-4-nitrobenzene. Although each of the four enzymes can be identified by its reactivity with specific substrates, all of the enzymes are active to differing degrees in the conjugation of glutathione with p-nitrobenzyl chloride. Assay conditions for a variety of substrates are included.
All four glutathione transferases have a molecular weight of 45,000 and are dissociable into subunits of approximately 25,000 daltons. Despite the similar physical properties and overlapping substrate specificities of these enzymes, only transferases A and C are immunologically related.
The feeding ecology of 3 coastal shark species—Atlantic sharpnose Rhizoprionodon terraenovae, bonnethead Sphyrna tiburo, and blacktip Carcharhinus limbatus shark—was examined in the northwest Gulf of Mexico (GOM). A total of 601 sharks (305 Atlantic sharpnose, 239 bonnethead, and 57 blacktip) were collected over 2 yr from recreational anglers in Galveston, TX. All individuals had stomach contents examined and a subset (50 Atlantic sharpnose, 50 bonnethead, and 36 blacktip sharks) was analyzed for stable isotopes (carbon, nitrogen, and sulfur) in muscle tissue, revealing short-term and long-term feeding strategies. Both blacktip and Atlantic sharpnose shark stomach contents consisted of teleost fishes with percent index of relative importance (%IRI) of 98.95 and 91.16, respectively, whereas bonnethead diets were dominated by crustaceans (%IRI = 87.20). Stable isotope analysis revealed bonnetheads had higher mean carbon (δ13C) and lower sulfur (δ34S) values, indicating inshore feeding and a preference for benthic invertebrates, respectively. Atlantic sharpnose and blacktip sharks were shown to feed on similar prey using stomach content analysis, yet Atlantic sharpnose sharks had a broader diet, including cephalopods and crustaceans in addition to teleost fishes. Differences were further established using nitrogen (δ15N) values, which were significantly lower for Atlantic sharpnose than blacktip sharks. Collectively, stomach contents and stable isotope analyses supported different feeding strategies of 3 common shark species. δ34S appeared to serve as a natural tracer, distinguishing benthic versus pelagic feeding patterns in elasmobranchs. This study provides important ecosystem-based feeding information of upper trophic-level predators in coastal waters of the northwestern GOM.
Top-predators may be extremely vulnerable to environmental
contaminants, such as organochlorines (OCs) and polycyclic
aromatic hydrocarbons (PAHs), mostly because of their position in
the trophic web. In this study, the use of skin biopsy is proposed as
a sensitive non-lethal technique for the toxicological assessment
of white shark (Carcharodon carcharias) living off the South
African coasts. In 2012, 15 specimens of great white shark were
sampled in the waters off Dyer Island and Geyser Rock. Then
OCs and PAHs were extracted from muscle and biomarkers
techniques for the evaluation of the cytochrome P4501A (CYP1A),
Vitellogenin (Vtg) and Zona Radiata Proteins (Zrp) in the skin
have been developed for the first time. The results showed levels
of OCs higher than those found in the literature, ranging in ng/g
dry weight (d.w.) from 6.80 to 21.26 for hexachlorobenzene (HCB),
from 86.72 to 1416.97 for DDTs and from 379.76 to 11284.31 for
polychlorinated biphenyls (PCBs). Furthermore, the values of both
pp’DDE/pp’DDT and pp’DDE/DDTs ratios suggest a recent DDT
introduction in the environment, probably related to its use against
malaria during the period 2000-2005 in KwaZulu-Natal. However,
PAHs showed the highest levels, almost double compared to OCs,
almost certainly due to the big oil traffic present in South Africa.
Regarding biomarkers results, important responses for CYP1A
have been highlighted, possibly due to a contamination by planar
compounds such as PAHs. Finally, the preliminary results of Vtg
and Zrp, biomarkers of estrogenic effects, showed the presence of
these proteins in sexually immature females and males.
Organochlorine (OC) pesticides and the more persistent polychlorinated biphenyls (PCBs) have well established dose-dependent toxicities to birds, fish and mammals in experimental studies, but the actual impact of OC pollutants on European marine top predators remains unknown. Here we show that several cetacean species have very high mean blubber PCB concentrations likely to cause population declines and suppress population recovery. In a large pan-European meta-analysis of stranded (n = 929) or biopsied (n = 152) cetaceans, three out of four species:- striped dolphins (SDs), bottlenose dolphins (BNDs) and killer whales (KWs) had mean PCB levels that markedly exceeded all known marine mammal PCB toxicity thresholds. Some locations (e.g. western Mediterranean Sea, south-west Iberian Peninsula) are global PCB “hotspots” for marine mammals. Blubber PCB concentrations initially declined following a mid-1980s EU ban, but have since stabilised in UK harbour porpoises and SDs in the western Mediterranean Sea. Some small or declining populations of BNDs and KWs in the NE Atlantic were associated with low recruitment, consistent with PCB-induced reproductive toxicity. Despite regulations and mitigation measures to reduce PCB pollution, their biomagnification in marine food webs continues to cause severe impacts among cetacean top predators in European seas.
A putative mechanism for maternal transfer of organic contaminants and total mercury was empirically demon- strated in a near-term pregnant female common thresher shark (Alopias vulpinus). Contaminants were measured in the liver and muscle tissue of the mother and her four embryos, as well as the embryos’ stomach contents. Concentrations of organic contaminants and mercury were found to be lower in the embryos’ livers than in the mother’s and were clearly measurable in the embryo stomach contents, which consisted of consumed ovulated eggs. Presence of high concentrations of organic contam- inants and mercury in embryos, prior to any exogenous exposure, provides clear evidence of maternal offloading in this species. In addition, the detection of these chemicals in the yolky stomach contents provides a mechanism by which oophagous elasmobranch females offload contaminants onto their young.
Polychlorinated biphenyls (PCBs) were quantified in liver tissues of bull sharks (Carcharhinus leucas) ranging in age from <4 wk to >3 yr. Summed values of PCBs (ΣPCBs) ranged from 310 ng/g to 22 070 ng/g (lipid wt) across age classes with ΣPCB concentrations for the youngest sharks in the present study (<4 wk; 5230 ± 2170 ng/g lipid wt) determined to not significantly differ from those quantified in >3-yr-old sharks, highlighting the extent of exposure of this young life stage to this class of persistent organic pollutants (POPs). Age normalization of PCB congener concentrations to those measured for the youngest sharks demonstrated a significant hydrophobicity (log octanol/water partition coefficient [KOW ]) effect that was indicative of maternal offloading of highly hydrophobic (log KOW ≥6.5) congeners to the youngest individuals. A distinct shift in the PCB congener profiles was also observed as these young sharks grew in size. This shift was consistent with a transition from the maternally offloaded signal to the initiation of exogenous feeding and the contributions of mechanisms including growth dilution and whole-body elimination. These results add to the growing pool of literature documenting substantially high concentrations of POPs in juvenile sharks that are most likely attributable to maternal offloading. Collectively, such results underscore the potential vulnerability of young sharks to POP exposure and pose additional concerns for shark-conservation efforts. Environ Toxicol Chem 2014;33:35-43. © 2013 SETAC.
The oil spill resulting from the explosion of the Deepwater Horizon drilling platform initiated immediate concern for marine wildlife, including common bottlenose dolphins in sensitive coastal habitats. To evaluate potential sublethal effects on dolphins, health assessments were conducted in Barataria Bay, Louisiana, an area that received heavy and prolonged oiling, and in a reference site, Sarasota Bay, Florida, where oil was not observed. Dolphins were temporarily captured, received a veterinary examination, and were then released. Dolphins sampled in Barataria Bay showed evidence of hypoadrenocorticism, consistent with adrenal toxicity as previously reported for laboratory mammals exposed to oil. Barataria Bay dolphins were 5 times more likely to have moderate-severe lung disease, generally characterized by significant alveolar interstitial syndrome, lung masses, and pulmonary consolidation. Of 29 dolphins evaluated from Barataria Bay, 48% were given a guarded or worse prognosis, and 17% were considered poor or grave, indicating that they were not expected to survive. Disease conditions in Barataria Bay dolphins were significantly greater in prevalence and severity than those in Sarasota Bay dolphins, as well as those previously reported in other wild dolphin populations. Many disease conditions observed in Barataria Bay dolphins are uncommon but consistent with petroleum hydrocarbon exposure and toxicity.
Life-history traits (size at age, growth rates, size and age at maturity, size of near-term embryos and litter sizes) of bonnetheads, Sphyrna tiburo, were analysed to test for latitudinal differences by comparing data collected from three areas along Florida's Gulf of Mexico coastline between March 1998 and September 2000. A total of 539 sharks were collected during the study: 207 in north-west Florida (latitude ~30°N), 176 in Tampa Bay (~28°N) and 156 in Florida Bay (~25°N). Male and female bonnetheads in north-west Florida had the largest predicted asymptotic sizes (1007 mm and 1398 mm TL, respectively) and attained the largest estimated median size at maturity (830 mm and 944 mm, respectively) and the oldest estimated median age at maturity (3.0+ years and 4.0+ years, respectively). The largest near-term embryos (297 mm TL) were also collected at the highest latitude, but no latitudinal difference in litter size was found. These differences in life-history traits provide supporting evidence that a pattern of latitudinal variation exists. Male and female bonnetheads in north-west Florida also had the fastest growth rate compared with the other locations, supporting the hypothesis that growth rate is inversely related to the length of the growing season (i.e. a pattern of countergradient variation exists).
Persistent organic pollutant bioaccumulation models have generally been formulated to predict bioconcentration and biomagnification. A third bioaccumulation process that can mediate chemical fugacity in an organism is bioamplification.Bioamplification occurs when an organism loses body weight and the chemical partitioning capacity occurs at a rate that is faster than the chemical can be eliminated.Although bioamplification has not been widely recognized as a bioaccumulation process, the potential consequences of this process are significant. Bioamplification causes an increase in chemical fugacity in the animal's tissues and results in there distribution of contaminants from inert storage sites to more toxicologically sensitive tissues. By reviewing laboratory and field studies, we have shown in this paper that bioamplification occurs across taxonomic groups that include, invertebrates,amphibians, fishes, birds, and mammals. Two case studies are presented, and constitute multi-life stage non-steady state bioaccumulation models calibrated for yellow perch and herring gulls. These case studies were used to demonstrate that bioamplification is predicted to occur under realistic scenarios of animal growth and seasonal weight loss. Bioamplification greatly enhances POP concentrations and chemical fugacities during critical physiological and behavioral events in an animal's life history, e.g., embryo development, juvenile stages, metamorphosis, reproduction, migration, overwintering, hibernation, and disease. Consequently,understanding the dynamics of bioamplification, and how different life history scenario scan alter tissue residues, may be helpful and important in assessing wildlife hazards and risks.
This study analyses the sexual activity and segregation of sand tiger sharks, Carcharias taurus, from Anegada Bay (Argentina). Reproduction-linked movements along the South American Atlantic coast were inferred from data from several SW Atlantic localities. Male sand tigers (n=162) matured at 193 cm total length (LT). Females (n=77) matured between 218 and 235 cm LT. These figures are similar to those from other populations, although size-at-maturity of males was slightly different from South African and Australian populations. In females, the size of ovarian follicles was positively correlated with gonadosomatic index and negatively correlated with hepatosomatic index, while the liver was significantly larger than in males. Sand tiger sharks were present in Anegada Bay from December to April. Males were significantly more abundant than females (2:1). Significant differences in reproductive condition through time were observed in males. During January and February males had seminal vesicles full of spermatozeugmata but by March and April the vesicles were empty. As the proportion of males with a lighter colouration peaked from January to March, it is very likely that mating takes place during January and February. The skewed sex-ratio during the mating season indicates a possible strong competition for mates among males, as observed in captivity. Males, females and some juveniles occur in Argentinean and Uruguayan waters, where mating takes place. Pregnant females occur in subtropical waters of southern Brazil, where they give birth. Given that pregnant and non-pregnant females occur at the same time in different zones, we suggest that the female reproductive cycle is biennial. Striking differences among migratory patterns of sand tiger sharks from the SW and NW Atlantic and South Africa were observed. © 2002 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights reserved.
The degree of reliance of newborn sharks on energy reserves from maternal resource allocation and the timescales over which these animals develop foraging skills are critical factors towards understanding the ecological role of top predators in marine ecosystems. We used muscle tissue stable carbon isotopic composition and fatty acid analysis of bull sharks Carcharhinus leucas to investigate early-life feeding ecology in conjunction with maternal resource dependency. Values of δ13C of some young-of-the-year sharks were highly enriched, reflecting inputs from the marine-based diet and foraging locations of their mothers. This group of sharks also contained high levels of the 20:3ω9 fatty acid, which accumulates during periods of essential fatty acid deficiency, suggesting inadequate or undeveloped foraging skills and possible reliance on maternal provisioning. A loss of maternal signal in δ13C values occurred at a length of approximately 100 cm, with muscle tissue δ13C values reflecting a transition from more freshwater/estuarine-based diets to marine-based diets with increasing length. Similarly, fatty acids from sharks >100 cm indicated no signs of essential fatty acid deficiency, implying adequate foraging. By combining stable carbon isotopes and fatty acids, our results provided important constraints on the timing of the loss of maternal isotopic signal and the development of foraging skills in relation to shark size and imply that molecular markers such as fatty acids are useful for the determination of maternal resource dependency.
Threshold tissue residue concentrations of polychlorinated biphenyls (PCBs) and 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQs) were derived from the published results of semi-field (i.e., field collected food items were used as a medium of exposure to PCBs in laboratory reared animals) or field toxicity studies conducted with seals, European otters and mink. Based on biomagnification factors (BMFs) and concentrations of PCBs or TEQs measured in fish fed in the diet of experimental aquatic mammals, dietary threshold concentrations were estimated. Hepatic vitamin A, thyroid hormone concentration, suppression of natural killer (NK) cell activity and proliferative response of lymphocytes to mitogens were the toxicity endpoints measured in aquatic mammals. Threshold concentrations for PCBs or TEQs in livers of aquatic mammals to elicit the physiological effects ranged from 6.6 to 11 µg PCBs/g (geometric mean: 8.7 µ/g) and 160 to 1400 pg TEQs/g (geometric mean: 520 pg/g), lipid weight, respectively. The BMFs for PCBs and TEQs varied depending on the marine mammal species, and therefore the dietary threshold concentrations could be referred only by a range of values (rather than a mean value), which were 10 to 150 ng PCBs/g and 1.4 to 1.9 pg TEQs/g, wet weight, for PCBs and TEQs, respectively.
A dietary feeding study with polycyclic aromatic hydrocarbons (PAHs) was conducted with juvenile Chinook salmon (Oncorhynchus tshawytscha) to mimic exposure from urban estuaries during their transition from freshwater to seawater. A significant reduction in mean fish dry weight was observed only for the highest doses; however, analysis of variance (ANOVA) using standard deviations and examination of the cumulative frequency plots revealed high variability among all treatments. The skewed fish weight distribution revealed a large number of small fish in several treatments compared with control fish. Analyses of whole-body lipids and several parameters in blood plasma related to growth and metabolism indicated alterations for most treatments. These results and trends in growth, plasma chemistry, and lipids as a consequence of PAH exposure were similar to those in fish exhibiting starvation, which we have termed "toxicant-induced starvation". Based on these results, we conclude that PAHs are toxic to salmonids at this life stage and the reduction in biomass and lipid stores observed here would have the potential to cause increased mortality for individuals during their first winter.
We studied the lipid dynamics (lipid contents, classes and fatty acids) during oogenesis and early embryo-genesis of 7 viviparous and 3 oviparous deepwater chondri-chthyans. Mature pre-ovulated ovarian follicles of all species were high in lipid content, indicative of large ener-getic expenditure and high maternal investment. Larger lipid reserves were found in viviparous dogshark (28–36% wet weight, ww) compared to oviparous chimaeras (19– 24% ww) and catshark, F. boardmani (18% ww). Neutral lipids and monounsaturated fatty acids were the main source of lipidic energy during vitellogenesis and gestation. For most species, there was a peak in total lipid content, levels of storage lipids and essential fatty acids at time of ovulation. InterspeciWc variation of total lipid yolk reserves and lipid class proWles was largely explained by diVerences in parity mode, reproductive (continuous vs. non-continu-ous oocytes development) strategy and depth-related physi-ological adaptations. Fatty acid proWles were less variable among species with the most important fatty acids includ-ing: 16:0, 18:19, 20:19, 20:46 and 22:63. These Wndings provide a greater biochemical understanding of diVerent maternal-embryonic relationships among chondri-chthyans, which can be used as a baseline for subsequent comparative studies.
A total of 772 bull sharks Carcharhinus leucas was caught in Natal's protective "shark nets" between 1978 and 1990. Confusion in distinguishing C. leucas from C. amboinensis resulted in their catch data being combined from 1966, when data collection began, to 1977. The catch rate of the species pair declined until 1977, recovered until the mid 1980s, but subsequently declined again. The trend in catch rate of C. leucas alone for the period 1978-1990 was similar, with minima of 0,70 sharks·km-net−1·year−1 in 1978 and 0,95 in 1990, and a maximum of 2,08 in 1986. Recaptures of six tagged sharks suggest that the species is not highly migratory. Catches, particularly of immature sharks, were highest at the northernmost beaches. Most bull sharks were caught in summer and in turbid water (mean water clarity 2,0 m). The sex ratio of the catch was 1 male to 1,3 females. Sizes ranged from 74 to 213 cm precaudal length, with modes of 141-145 cm (males) and 171-175 cm (females). Size at maturity for both sexes was between 180 and 190 cm. The mating season was prolonged but with a summer peak. Seven gravid females were examined; the mean litter size was 8,7 embryos and size at birth was approximately 55 cm. Fluke infections were observed on 9 per cent of animals examined. As size increased there was a shift in diet, in terms of frequency of occurrence, from teleost to elasmobranch predominance. There was a high incidence of benthic and demersal species in the stomachs. Minor prey groups included mammals, birds, turtles, molluscs and crustaceans. Scavenging appeared to be important.
This study examines life history patterns and correlations between traits related to body size, reproduction, age, and growth in sharks, using data from 230 populations representing 164 species, 19 families, and 7 orders. The analysis focused on interspecific life history variability, but intraspecific and intrapopulation variation were also considered. Interspecifically, body size correlated positively with litter size and offspring size, and a tradeoff between litter size and offspring size was found after factoring out the effects of body size. Offspring size correlated negatively with growth completion rate (K), but the correlation became positive after correcting for the effects of body size. Parental size for males and females was negatively correlated with K. Parental size and size at maturity exhibited a strong positive correlation, with sexual maturity occurring at about 75% of maximum size in both sexes. Males were 10% smaller than females and reached their maximum length 34% faster than females on average. Females tend to mature later and live longer than males, but age at maturity is reached at about 50% of maximum age in both sexes. Maximum size and empirical longevity were not significantly correlated in females, but were positively correlated in males. Size and age at maturity also exhibited a moderate positive correlation in males, especially after excluding data for Squalus acanthias. Principal component and cluster analyses were used to reflect similarities among life history traits of 40 populations from 34 species, and at least three separate life history strategies were identified.
1.Under the Endangered Species Act, the National Marine Fisheries Service has authority to protect listed species from any adverse actions that may jeopardize the population's ability to recover and increase to sustainable levels. Listed salmon species in the northwest United States are known to travel through urban areas in their migration from river to ocean. Species such as the chinook salmon (Oncorhynchus tshawytscha) often spend several weeks in these urban estuaries where they can be highly exposed to urban-related contaminants that reside in the sediments and accumulate in their prey species. The concern is that these contaminants are bioaccumulated to levels that may impact the ability of individual salmon to grow and mature normally. This paper provides a framework for determining the tissue and sediment concentrations of polychlorinated biphenyls (PCBs) that are likely protective against adverse effects in listed salmonid species.2.The relevant ecotoxicological literature was examined and 15 studies were selected that met the pre-established criteria outlined here. For each study, the lowest tissue concentration (residue) of total PCBs associated with a biological response was selected. The tissue concentration associated with the 10th percentile of these 15 studies was chosen to represent the residue effect threshold (RET) above which wild juvenile salmonids would be expected to exhibit adverse sublethal effects from accumulated PCBs. This value (2.4 μg PCBs g−1 lipid) is expressed in terms of the lipid-normalized concentration because of the large effect lipid can have on the expressed toxicity and the substantial variability in lipid content observed in salmonids over their life cycle.3.A sediment concentration that is expected to produce the RET was then determined using the biota-sediment accumulation factor approach. The sediment effect threshold, which varies with the total organic carbon content in sediment, is the level above which adverse effects may be expected in juvenile salmonids due to accumulation of PCBs from environmental exposure. Bioaccumulation of PCBs was examined in one river system as a model for determining an appropriate bioaccumulation factor for wild juvenile chinook salmon.4.Evaluation of exposure to potentially deleterious concentrations of PCBs based on tissue residues is the preferred approach; however, the sediment effect threshold may also be used in cases where bioaccumulation has been characterized in an estuary. The threshold values presented here are intended as interim guidelines that should be modified as more data become available. Additionally, because of the uncertainty around many of the factors and assumptions that comprise the single threshold effect values, it is recommended that future studies be employed to help determine a range of acceptable values that would afford protection under various environmental and biological conditions. Published in 2002 by John Wiley & Sons, Ltd.
Elasmobranchs living in rivers and estuaries may be highly susceptible to environmental and anthropogenic changes to coastal habitats. To address this, patterns of movement of 67 juvenile bull sharks (Carcharhinus leucas) were examined in the Caloosahatchee River between 2003 and 2006 using an array of 25 acoustic receivers. Individuals were monitored for periods of 1–460 days with most present for periods of weeks to months. Individuals utilised the entire monitored section of the river (∼27 km) and also moved upriver beyond the extent of the acoustic array. Daily activity spaces of individuals ranged from 0 to 14 km with most <5 km. Monthly mean home ranges were 0.9–5.6 km and although home-range sizes were consistent through time, location of individuals within the river changed through time. Individuals moved upstream during the day and downstream at night and this pattern persisted across years. Based on data collected from depth transmitters in 2006, individuals swam closer to the surface at night and remained in deeper water during the day, suggesting further diurnal patterns in habitat use. Long-term consistent use of this habitat by young C. leucas suggests this population is highly dependent on the Caloosahatchee River as a nursery area.
The composition of lipids and fatty acids was determined for the livers, muscle, pancreas, kidney and stomach fluids of deepwater
chondrichthyan species (including 11 squaliformes, 3 chimaeriformes, 1 hexanchiforme and 3 carcharhiniformes) caught as bycatch
from continental waters off south-eastern Australia. The lipid class, fatty acid and fatty alcohol composition differed markedly
in each tissue and in each species. The lipid and fatty acid composition of large, lipid-rich (38–70% wet weight, ww) livers
demonstrated the multifunctional role of this organ in: lipid distribution, storage and biosynthesis, and buoyancy regulation.
In the liver, the importance of certain lipids (including squalene, diacylglyceryl ethers, triacylglycerols and to a lesser
extent wax esters) as mediators of buoyancy varied according to lifestyle and habitat. Less variability was observed in the
muscle profiles, characterized by low lipid content (<1.0% ww) and high relative levels of polar lipids (>70%). The lipid
and fatty acid profiles of the kidney and pancreas showed the highest intraspecific variability, suggesting these organs also
have complex roles in lipid storage and metabolism. Overall intra- and interspecific differences in the tissue fatty acid
profiles could be related to differences in a number of factors including phylogeny, habitat (depth), buoyancy regulation
and diet and presumably also reflect different ecological roles. The lipid and fatty acid profiles are the first published
for Rhinochimaera pacifica, Chimaera lignaria and Figaro boardmani and the first to demonstrate interspecific variation in lipid profiles of various tissues of deepwater chondrichthyans. The
application of multivariate analysis to lipid class and fatty acid tissue profiles in chondrichthyans inferred dietary differences
and metabolic preferences between species and habitats. These results have important implications for the future use of fatty
acids as dietary tracers in chondrichthyan research.
To examine variation in diet and daily ration of the bonnethead shark, Sphyrna tiburo (Linnaeus 1758), animals were collected from three areas in the eastern Gulf of Mexico: northwest Florida (∼29°40′N, 85°13′W),
Tampa Bay near Anclote Key (∼28°10′N, 82°42.5′W), and Florida Bay (∼24°50′N, 80°48′W) from March through September, 1998–2000.
In each area, diet was assessed by life stage (young-of-the year, juveniles, and adults) and quantified using five indices:
percent by number (%N), percent by weight (%W), frequency of occurrence (%O), index of relative importance expressed on a
percent basis (%IRI), and %IRI based on diet category (%IRIDC). Diet could not be assessed for young-of-the-year in Tampa Bay or Florida Bay owing to low sample size. Diet analysis showed
an ontogenetic shift in northwest Florida. Young-of-the-year stomachs from northwest Florida (n=68, 1 empty) contained a mix of seagrass and crustaceans while juvenile stomachs (n=82, 0 empty) contained a mix of crabs and seagrass and adult stomachs (n=39, 1 empty) contained almost exclusively crabs. Crabs made up the majority of both juvenile and adult diet in Tampa Bay
(n=79, 2 empty, and n=88, 1 empty, respectively). Juvenile stomachs from Florida Bay (n=72, 0 empty) contained seagrass and a mix of crustaceans while adult stomachs contained more shrimp and cephalopods (n=82, 3 empty). Diets in northwest Florida and Tampa Bay were similar. The diet in Florida Bay was different from those in
the other two areas, consisting of fewer crabs and more cephalopods and lobsters. Plant material was found in large quantities
in all stomachs examined from all locations (>15 %IRIDC in 6 of the 7 life stage-area combinations, >30 %IRIDC in 4 of the 7 combinations, and 62 %IRIDC in young-of-the-year diet in northwest Florida). Using species- and area-specific inputs, a bioenergetic model was constructed
to estimate daily ration. Models were constructed under two scenarios: assuming plant material was and was not part of the
diet. Overall, daily ration was significantly different by sex, life stage, and region. The bioenergetic model predicted increasing
daily ration with decreasing latitude and decreasing daily ration with ontogeny regardless of the inclusion or exclusion of
plant material. These results provide evidence that bonnetheads continuously exposed to warmer temperatures have elevated
metabolism and require additional energy consumption to maintain growth and reproduction.
Shark nurseries, or nursery areas, are geographically discrete parts of a species range where the gravid females of most species of coastal sharks deliver their young or deposit their eggs, and where their young spend their first weeks, months, or years. These areas are usually located in shallow, energy rich coastal areas where the young find abundant food and have little predation by larger sharks. Nurseries are characterized by the presence of both gravid females and free swimming neonates. Neonates are young bearing fresh, unhealed umbilical scars in the case of placental species, or those at or near the birth size in aplacental species. Bulls Bay, South Carolina, is a nursery for the blacknose, spinner, finetooth, blacktip, sandbar, dusky, Atlantic sharpnose, scalloped hammerhead, and smooth dogfish sharks. The lemon shark has its nursery in shallow waters of south Florida and the Bahamas. The bull shark has its nursery in the lagoons of the east coast of central Florida.
Intensive human activities aggravate environmental pollution, particularly in the coastal environment. Sixteen priority polycyclic aromatic hydrocarbons (PAHs) were determined in the sediments and marine species from Zhanjiang Harbor, a large harbor in China. The total PAH concentrations ranged from 151 to 453 ng/g dry weight (dw) in sediments and from 86.7 to 256 ng/g wet weight (ww) in organism tissues. High levels of PAHs occurred in the sample sites next to the estuary. A decrease in PAH levels was observed in comparison to the previous survey prior to 2012. Fish exhibited lower lipid weight normalized PAH concentrations than the other species, which may be related to their efficient metabolic transformation. Three ring PAHs dominated both in marine sediments and species, but low molecular weight PAHs exhibited higher proportions in biota than in sediments (p < 0.05). Petrogenic and pyrolytic sources both contributed to the occurrence of PAHs, and the latter became increasingly important in the study area. The ecological risk from PAHs in the sediments was relatively low (9% incidence of adverse biological effect) according to the effects-based sediment quality guideline values. Exposure to PAHs via consuming seafoods might pose a health risk to local residents. Overall, these results revealed anthropogenic activities in the coastal area have an impact on the local ecosystem.
Polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and polychlorinated dibenzo-p-dioxins and -furans (PCDD/Fs) were measured in a temperate, deep-sea ecosystem, the Avilés submarine Canyon (AC; Cantabrian Sea, Southern Bay of Biscay). There was an increase of contaminant concentration with the trophic level of the organisms, as calculated from stable nitrogen isotope data (δ¹⁵N). Such biomagnification was only significant for the pelagic food web and its magnitude was highly dependent on the type of top predators included in the analysis. The trophic magnification factor (TMF) for PCB-153 in the pelagic food web (spanning four trophic levels) was 6.2 or 2.2, depending on whether homeotherm top predators (cetaceans and seabirds) were included or not in the analysis, respectively. Since body size is significantly correlated with δ¹⁵N, it can be used as a proxy to estimate trophic magnification, what can potentially lead to a simple and convenient method to calculate the TMF. In spite of their lower biomagnification, deep-sea fishes showed higher concentrations than their shallower counterparts, although those differences were not significant. In summary, the AC fauna exhibits contaminant levels comparable or lower than those reported in other systems.
Biomagnification (increase in contaminant concentrations at successively higher levels of trophic web), is a process that can transversally impair biodiversity and human health. Most research shows that biomagnification should be higher at poles with northern sites having a major tendency to biomagnify Persistent Organic Pollutants (POPs) through their marine food webs. We investigated the biomagnification degree into two marine trophic webs combining carbon and nitrogen stable isotopes and POP analyses. We showed that the Antarctic trophic web was more depleted than the sub-Arctic one and the differences highlighted for the basal part could explain the difference in length between them. Concentrations of polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), and p,p’-DDE were of the same order of magnitude in the two polar trophic webs, with some values surprisingly higher in the Antarctic than sub-arctic organisms: PCBs ranged (average ± standard deviation) 1.10 ± 0.39–12.93 ± 7.62, HCB <0.10–7.28 ± 5.32, and p,p’-DDE 0.52 ± 0.18–11.36 ± 5.3 ng/g wet weight (wt) in the Antarctic organisms, and 0.53–5.08, <0.10–1.48, and 0.27 ± 0.35–5.46 ± 1.73 ng/g wet wt, respectively, in the sub-Arctic ones. The contribution of tetra- and penta-CBs to the ∑PCBs was 10–65% in the Antarctic species and 15–45% in the Arctic species. The relationships between POPs and trophic levels, and the information obtained by the Trophic Magnification Factor revealed that the Antarctic trophic web had a greater tendency to biomagnify PCBs and p,p’-DDE than its sub-Arctic counterpart. POP availability in the environment and specific ecological features may play an important role in the bioaccumulation, and biomagnification is apparently less important than bioconcentration.
Chronic organochlorine (OC) exposure has been shown to cause immune impairment in numerous vertebrate species. To determine if elasmobranchs exhibited compromised immunity due to high OC contamination along the coastal mainland of southern California, innate immune function was compared in round stingrays (Urobatis halleri) collected from the mainland and Santa Catalina Island. Proliferation and phagocytosis of peripheral blood, splenic, and epigonal leukocytes were assessed. Percent phagocytosis and mean fluorescence intensity (MFI) were evaluated by quantifying % leukocytes positive for, and relative amounts of ingested fluorescent E. coli BioParticles. Total cell proliferation differed between sites, with mainland rays having a higher cell concentration in whole blood. ∑PCB load explained significantly higher % phagocytosis in blood of mainland rays, while ∑PCB and ∑pesticide loads described increased splenic % phagocytosis and MFI in the mainland population. Data provides evidence of strong OC-correlated immunostimulation; however, other site-specific environmental variables may be contributing to the observed effects.
Pigs have often been suggested to be a useful model for humans, when investigating CYP dependent events, like drug metabolism. However, comprehensive knowledge about the constitutive expression of the major CYP and corresponding transcription factors is limited. We compared the constitutive expression of aryl hydrocarbon receptor, constitutive androstane receptor and pregnane X receptor and CYP1A1, CYP1A2, CYP2A, CYP2E1 and CYP3A in liver, adipose tissue, muscle and small intestine in pigs, as well as the expression along the length of the small intestine and colon. Tissue samples were taken from female pigs, and analyzed for gene expression, as well as CYP dependent activity using qPCR and specific probe substrates, respectively. For all investigated transcription factors and CYPs the expression and activity was highest in the liver. CYP1A1 and CYP3A expression and activity was shown in all investigated tissues. Along the small intestine and colon the expression and activity of CYP1A1 and CYP3A was gradually decreased. The results demonstrated, similarity to that reported for humans, and hence adds to the use of pigs as a model for humans.
Marine ecosystems are constantly being threatened by contaminants produced by human activities. There is an urge to better understand their impacts on marine organisms and develop reliable tools for biomonitoring studies, while also assessing their potential impacts on human health. Given their position on top of food webs, sharks are particularly susceptible to bioaccumulation, making them potential sentinel species of marine contamination. The main objective of this study was to find suitable biomarkers for future marine pollution biomonitoring studies by correlating biochemical responses with tissue contaminant body burden in blue sharks (Prionace glauca), a species heavily caught and consumed by humans, while also addressing their general health. The chemical contaminants analysed comprised different persistent organic pollutants (POPs) families from polychlorinated compounds to brominated flame retardants (BFRs) and perfluorinated compounds (PFCs) and different trace and heavy metals. Concentrations of some contaminants in sharks' tissues were found to be above the legally allowed limits for human consumption. A canonical correspondence analysis (CCA) was performed and some strong associations were found between biochemical responses and contaminants' accumulation levels. DNA damage and lipid peroxidation levels, as well as the inhibition of the antioxidant enzyme glutathione peroxidase, were the main effects and consequences of contamination. The impact of contamination on these vital macromolecules underlines the suboptimal conditions of the sampled P. glauca, which can ultimately lead to the degradation of core ecological aspects, such as swimming, feeding, and reproduction. It can be concluded that P. glauca demonstrates great potential to be used as environmental sentinel and suitable biomarker candidates were identified in this work. Moreover, this study also highlights the risks that the consumption of blue shark derived products can pose to human health, which is of upmost interest as the sampled organisms were still juveniles and already presented values above regulatory limits.
Polychlorinated biphenyls (PCBs) are ubiquitous pollutants in the marine environment that are known to accumulate in apex predators such as sharks. Liver samples from dusky Carcharhinus obscurus, sandbar Carcharhinus plumbeus, and white Carcharodon carcharias sharks from south-eastern Australian waters were analysed for the seven indicator PCBs 28, 52, 101, 118, 138, 153 and 180. Median ∑PCBs were significantly higher in white than sandbar sharks (3.35 and 0.36μgg(-1) lipid, respectively, p=0.05) but there were no significant differences between dusky sharks (1.31μgg(-1) lipid) and the other two species. Congener concentrations were also significantly higher in white sharks. Significant differences in PCB concentrations between mature and immature dusky (3.78 and 0.76μgg(-1) lipid, respectively) and sandbar (1.94 and 0.18μgg(-1) lipid, respectively) sharks indicated that PCB concentrations in these species increased with age/growth. Higher-chlorinated congeners (hexa and heptachlorobiphenyls) dominated results, accounting for ~90% of ∑PCBs.
Persistent organic pollutants (POPs) and stable isotopes of nitrogen (delta N-15) were measured in zooplankton (6 species), a benthic invertebrate (Anonyx nugax), Arctic cod (Boreogados saida), seabirds (6 species), and ringed seals (Phoca hispida) collected in 1998 in the Northwater Polynya to examine effects of biological and chemical factors on trophic transfer of POPs in an Arctic marine food web. Strong positive relationships were found between recalcitrant POP concentrations (lipid corrected) and trophic level based on stable isotopes of nitrogen, providing clear evidence of POP biomagnification in Arctic marine food webs. Food web magnification factors (FWMFs), derived from the slope of the POP-trophic level relationship, provided an overall magnification factor for the food web but over and underestimated biomagnification factors (BMFs) based on predator-prey concentrations in poikilotherms (fish) and homeotherms (seabirds and mammals), respectively. Greater biomagnification in homeotherms was attributed to their greater energy requirement and subsequent feeding rates. Within the homeotherms, seabirds had greater BMFs than ringed seals, consistent with greater energy demands in birds. Scavenging from marine mammal carcasses and accumulation in more contaminated winter habitats were considered important variables in seabird BMFs. Metabolic differences between species resulted in lower than expected BMFs, which would not be recognized in whole food web trophic level-POP relationships. The use of Sigma POP groups, such as Sigma PCB, is problematic because FWMFs and BMFs varied considerably between individual POPs. FWMFs of recalcitrant POPs had a strong positive relationship with log octanol-water partition coefficient (K-ow). Results of this study show the utility of using delta N-15 to characterize trophic level and trophic transfer of POPs but highlight the effects of species and chemical differences on trophic transfer of POPs that can be overlooked when a single magnification factor is applied to an entire food web.
Trophic position (TP) and body mass are traits commonly used to predict organochlorine (OC) burdens. Sharks, however, have a variety of feeding and life-history strategies, and metabolize lipid uniquely. Because of this diversity, and the lipid-association of OCs, the dynamics of OC accumulation in sharks may be ineffectively predicted by stable isotope-derived TP and body mass as is typical for other taxa. This study compared ontogenetic OC profiles in the dusky (Carcharhinus obscurus) and white shark (Carcharodon carcharias), which differ in metabolic thermoregulation and TP throughout their ontogeny. While greater OC concentrations were observed in the larger bodied and higher TP white shark (e.g., p,p'-DDE: 20.2 ± 2.7 ng/g, vs. 9.3 ± 2.2 ng/g in the dusky shark), slopes of growth-dilution corrected concentrations with age were equal to those of the dusky shark. Similar ontogenetic TP increases in both species, less frequent white shark seal predation than previously assumed, or inaccurate species-specific growth parameters are possible explanations. Inshore habitat use (indicated by δ(13) C values) and mass were important predictors, in white and dusky sharks respectively, both of overall compound profiles and select OC concentrations. This study clarified our understanding of TP and body mass as reliable predictors of interspecific OC accumulation in sharks, whereas regional endothermy and diet shifting were shown to have less impact on overall rates of accumulation. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
Length at age and growth rates for 54 blacktip, Carcharhinus limbatus, and 15 spinner, C. brevipinna, sharks from the northwestern Gulf of Mexico were estimated from bands formed seasonally in vertebral centra. For C. limbatus, males mature at 130 cm total length (TL) or 4-5 yr, females at 150-155 cm TL or 7-8 yr. With sexes combined, von Bertalanffy curve parameter estimates were: L oo=176 cm TL, K = 0.274, t o=-1.20 yr. The oldest specimen, a 171 cm TL female, was 9.3 yr of age. For C. brevipinna, males mature at 170 cm TL or 6-7 yr of age, females at 180 cm TL or 7-8 yr of age. The oldest specimen, a 208 cm TL female, was 11.3 yr of age. With sexes combined, von Bertalanffy curve parameter estimates were: L oo=214 cm TL, K = 0.212, t o=-1.94 yr. Growth rates for both species are in excess of 20 cm/yr for the first 2 yr, about 10 cm/yr through adolescence, and 5 cm/yr or less for adults.
We have previously reported that high accumulation of dioxins and related compounds induced cytochrome P450 (CYP1s) isozymes in the liver of wild Baikal seals, implying the enhanced hydroxylation of polychlorinated biphenyls (PCBs). The present study attempted to elucidate the residue concentrations and patterns of PCBs and hydroxylated PCBs (OH-PCBs) in the livers of Baikal seals. The hepatic residue concentrations were used to assess the potential effects of PCBs and OH-PCBs in combination with the analyses of serum thyroid hormones, hepatic mRNA levels, and biochemical markers. The hepatic expression levels of CYP1 genes were positively correlated with the concentration of each OH-PCB congener. This suggests chronic induction of these CYP1 isozymes by exposure to PCBs, and hydroxylation of PCBs induced by CYP1s. Hepatic mRNA expression monitoring using a custom microarray showed that chronic exposure to PCBs and their metabolites alters the gene expression levels related to oxidative stress, iron ion homeostasis, and inflammatory responses. In addition, the concentrations of OH-PCBs were negatively correlated with thyroxine (T4) levels and the ratios of triiodothyronine (T3)/reverse triiodothyronine (rT3). These observations imply that Baikal seals contaminated with high levels of OH-PCBs may undergo the disruption of mechanisms related to formation (or metabolism) of T3 and T4 in the liver.
The Greenland shark Somniosus microcephalus is an opportunistic feeder, a top predator, and a very long-lived species. The brain, liver, red and white muscle, gonads, fat, skin, pancreas, and spleen of Greenland sharks from NE Greenland fjords were analysed for PCBs, PCDDs/DFs, PBDEs; DDT isomers; HCH isomers; dieldrin; endrin; HCB; Cd, Hg, Pb, and Se.
PCBs (2.01–103 ng/g wet wt) and PBDEs (7.9–3050 pg/g wet wt) were detected in most of the samples. PCDDs/DFs showed high values when detected. DDTs, HCB and HCHs were only detected in some tissues. The ΣTEQ was 5.76 pg/g in muscle.
Cadmium mainly accumulated in the pancreas and liver (19.6 and 10.7 mg/kg dry wt, respectively); mercury in red muscle (4.10–6.91 mg/kg dry wt); selenium in the pancreas (3.57 mg/kg dry wt) and spleen (1.95 mg/kg dry wt); lead in the skin (0.358 mg/kg dry wt). The selenium-mercury ratio in the liver was also evaluated.
While contaminant concentrations have been reported for elasmobranchs around the world, no studies have examined bioaccumulation patterns across male and female age classes. The round stingray (Urobatis halleri) is a local benthic species that forages near areas of high organochlorine contamination and represents a good elasmobranch model. Polychlorinated biphenyls (PCBs), DDT, and chlordanes were measured in juvenile and adult male and female stingrays from areas in southern California, USA (n = 208), and a nearby offshore island, Santa Catalina (n = 34). Both mainland juvenile male and female stingrays showed a significant dilution effect. After maturity, summed contaminant concentrations significantly increased with size for adult males (median 11.1 µg/g lipid wt) and females (5.2 µg/g lipid wt). However, the rate of bioaccumulation was substantially greater in male stingrays than in females, likely a result of the females' ability to offload contaminants to offspring during pregnancy. In addition, males and females showed significant differences in their contaminant profiles, suggesting differential habitat use. Male and female stingrays collected from Santa Catalina Island had significantly lower concentrations (0.51 µg/g and 0.66 µg/g lipid wt, respectively), approximately 5 times less than those of mainland animals. Potential toxicity effects mediated through activation of the aryl hydrocarbon receptor were explored through ethoxyresorufin-O-deethylase (EROD) activity assays. Mainland male stingrays exhibited significantly greater EROD activities than Catalina males (481 pmol/min/mg protein and 55 pmol/min/mg protein, respectively); however, activity levels in female stingrays from both locations were comparable (297 pmol/min/mg protein and 234 pmol/min/mg protein, respectively) and lower than those in mainland males. The results suggest that PCBs and/or other structurally related contaminants may be inducing a biological response in mainland males but not females, possibly the result of a dampening effect of estradiol; however, the exact physiological repercussions of exposure remain to be determined. Environ Toxicol Chem 2014;33:1380–1390. © 2014 SETAC
Stomach contents and vertebrae from neonate and juvenile blacktip sharks Carcharhinus limbatus (n= 334) were examined to describe their diet, feeding patterns and growth within the Timbalier–Terrebone Bay complex, LA, U.S.A. In the study area, both neonate and juvenile C. limbatus feed primarily on gulf menhaden Brevoortia patronus. However, based on the index of relative importance (IRI), gulf menhaden constituted a larger portion of the diet of neonates (84·05 %IRI) than for juveniles (47·91 %IRI). An increase in the index of relative fullness between the afternoon and dusk time intervals and a large decrease in the percentage of empty stomachs between the night and early morning time intervals suggested that these fish exhibited a diel feeding pattern with crepuscular periods being the times of highest feeding activity. A higher percentage of empty stomachs (neonates 68% and juveniles 39%) and a significantly lower growth rate (age 0+ year C. limbatus, 0·62 mm day−1; age 1+ year fish, 0·89 mm day−1) could indicate that neonate C. limbatus are less efficient predators than older conspecifics.
The mammalian Ah receptor (AhR) controls the expression of the CYP1A1 gene and may also mediate the toxic effects of chlorinated dioxins and related compounds. Little is known about the presence and characteristics of the AhR in non-mammalian species. Recent studies have identified an AhR in fish, consistent with their sensitivity to dioxin toxicity. However, the AhR may be lacking in many species of marine invertebrates. Thus, invertebrate species may be less susceptible to dioxin effects, or may show different structure-activity relationships from those seen in vertebrates. The AhR may have evolved more than 450 million years ago in response to compounds present in the environment of early fishes, or to fulfill some physiologic role, as yet unidentified.
The bull shark, Carcharhinus leucas, is the most common shark in the brackish Indian River lagoon system on the central east coast of Florida. The biology of the lagoon population was studied between May 1975 and May 1979. There was substantial spatial and seasonal variation in catch rates with gill nets. Bull sharks were usually most abundant in the low-salinity lagoon basins. Catch rates were generally highest in the spring and fall and were always higher at night than day. No specimens were netted during the winter although bull sharks are known to be present during that season. The permanent lagoon population was composed entirely of newborn young and juveniles up to 202 cm TL. As they approach maturity, the subadults leave the estuary. Pregnant adult females return to lagoon waters in late spring and summer to give birth. One pregnant female 249 cm TL was captured during this study. Juvenile bull sharks in the lagoon system fed primarily on stingrays and marine catfishes.
Inducible proteins are attractive candidates for biomarkers-i.e. biological responses that reflect exposure to, or effects of, environmental pollutants in an organism (1). Blomarkers are increasingly regarded as powerful and informative tools in ecotoxicology and environmental management (1).
Sharks are marine consumers believed to occupy top positions in marine food webs. But surprisingly, trophic level estimates for these predators are almost non-existent. With the hope of helping better define the ecological role of sharks in marine communities, this paper presents standardized diet compositions and trophic levels calculated for a suite of species. Dietary composition for each species was derived from published quantitative studies using a weighted average index that takes into account sample size in each study. The trophic level (TL) values of the 11 food types used to characterize the diet (obtained from published accounts) were then used to calculate fractional trophic levels for 149 species representing eight orders and 23 families. Sharks as a group are tertiary consumers (TL>4), and significant differences were found among the six orders compared, which were attributable to differences between orectolobiforms (TL<4) and all other orders, and between hexanchiforms and both carcharhiniforms and squatiniforms. Among four families of carcharhiniform sharks, carcharhinids (TL=4.1, n=39) had a significantly higher TL than triakids (TL=3.8, n=19) and scyliorhinids (TL=3.9, n=21), but not sphyrnids (TL=3.9, n=6). When compared to trophic levels for other top predators of marine communities obtained from the literature, mean TL for sharks was significantly higher than for seabirds (n=28), but not for marine mammals (n=97). Trophic level and body size were positively correlated (r s =0.33), with the fit increasing (r s =0.41) when the three predominantly zooplanktivorous sharks were omitted, and especially when considering only carcharhinid sharks (r s =0.55).
Length at age and growth rates for 59 bull sharks, Carcharhinus leucas, collected from the northern Gulf of Mexico were estimated from the band patterns formed seasonally in the vertebral centra. The combined age at length data for both sexes were applied to a von Bertalanffy growth model producing parameter estimates of L = 285 cm TL, K = .076, t0 = –3.0 yr. Lengths at age for males and females were similar except that males did not attain as great a length as females. Growth was apparently slow and varied among individuals, but in general, was estimated to be 15–20 cm yr–1 for the first five years, 10 cm yr–1 for years 6–10, 5–7 cm yr–1 for years 11–16, and less than 4–5 cm yr–1 thereafter. Males mature at 210–220 cm TL or 14–15 yr of age; females mature at>225 cm TL or 18+ yr of age. The largest male (245 cm TL) was 21.3 yr old; the largest female (268 cm TL) was 24.2 yr old.