White Sucker Research Articles

A Bayesian assessment of tumour prevalence in brown bullhead and white sucker from the Canadian waters of the Great Lakes

Liver and skin tumours in brown bullhead (Ameiurus nebulosus) and white sucker (Catostomus commersoni) have been associated with contamination of the aquatic environment. In this study, we present a Bayesian hierarchical logistic-Bernoulli framework that considers the role of fish covariates (e.g., age, total weight, gonad weight, liver weight, fork length) on tumour prevalence to identify the presence of “hot-spots” around the Canadian waters of the Great Lakes, where high fish tumour frequencies are registered. We developed methods to discern the degree of impairment that are either based on the comparison of tumour frequencies in contaminated (or impacted) sites against those predicted in their corresponding reference areas, or the assessment of the prevailing conditions in impaired sites independently, without the need to establish baseline conditions for comparison purposes. Our modelling study predicts low frequencies of neoplastic tumours in all the impacted locations. In contrast, the same comparisons with the preneoplastic lesions provided evidence of distinct differences between impacted and reference sites in Jackfish Bay, St. Mary’s River, Niagara River, Hamilton Harbour, and Bay of Quinte. We also found weak to moderately strong relationships between tumour occurrence and fish physical characteristics that varied considerably in terms of their strength and nature (sign) among the different locations. Our study concludes that the prevalence of neoplastic tumours appears to have reached acceptable levels around the Great Lakes, but the distinctly higher levels of preneoplasms in several impacted locations underscore the need to improve our understanding of the lesions that may lead to carcinogenesis.

Potential Influence of Sewage Phosphorus and Wet and Dry Deposition Detected in Fish Collected in the Athabasca River North of Fort McMurray

The health of fish is a primary indicator of ecosystem response in the Oil Sands Region of northeastern Alberta. However, industrial activity is accompanied by other stressors, such as the discharge of sewage, municipal activity, forest fires, and natural weathering and erosion of bitumen. To combat the spatial confounding influences, we examined white sucker (Catostomus commersonii) captured in the Athabasca River at sites over time (2011–2019) and included covariates to account for the possible sources of influence. The analyses suggest spatially heterogeneous influences of natural factors on fish, such as discharge and air temperature, but also the influence of sewage phosphorus and precipitation. Among the stressors examined here, precipitation may be the most complex and may include a mixture of sources including inputs from tributaries, urban activity, industrial development, and forest fires. Although suggestive, the attribution of variance and detection of changes are affected by sample sizes in some years; these analyses may have missed effects or misspecified important relationships, especially in males. Despite these limitations, the analyses suggest potential differences may be associated with precipitation and highlight the need to integrate robust information on known and suspected stressors in future monitoring of aquatic ecosystems in the oil sands region and beyond.

Phylogeographic Genetic Diversity in the White Sucker Hepatitis B Virus across the Great Lakes Region and Alberta, Canada.

Hepatitis B viruses belong to a family of circular, double-stranded DNA viruses that infect a range of organisms, with host responses that vary from mild infection to chronic infection and cancer. The white sucker hepatitis B virus (WSHBV) was first described in the white sucker (Catostomus commersonii), a freshwater teleost, and belongs to the genus Parahepadnavirus. At present, the host range of WSHBV and its impact on fish health are unknown, and neither genetic diversity nor association with fish health have been studied in any parahepadnavirus. Given the relevance of genomic diversity to disease outcome for the orthohepadnaviruses, we sought to characterize genomic variation in WSHBV and determine how it is structured among watersheds. We identified WSHBV-positive white sucker inhabiting tributaries of Lake Michigan, Lake Superior, Lake Erie (USA), and Lake Athabasca (Canada). Copy number in plasma and in liver tissue was estimated via qPCR. Templates from 27 virus-positive fish were amplified and sequenced using a primer-specific, circular long-range amplification method coupled with amplicon sequencing on the Illumina MiSeq. Phylogenetic analysis of the WSHBV genome identified phylogeographical clustering reminiscent of that observed with human hepatitis B virus genotypes. Notably, most non-synonymous substitutions were found to cluster in the pre-S/spacer overlap region, which is relevant for both viral entry and replication. The observed predominance of p1/s3 mutations in this region is indicative of adaptive change in the polymerase open reading frame (ORF), while, at the same time, the surface ORF is under purifying selection. Although the levels of variation we observed do not meet the criteria used to define sub/genotypes of human and avian hepadnaviruses, we identified geographically associated genome variation in the pre-S and spacer domain sufficient to define five WSHBV haplotypes. This study of WSHBV genetic diversity should facilitate the development of molecular markers for future identification of genotypes and provide evidence in future investigations of possible differential disease outcomes.

Are Muskellunge Affecting Fish Communities in Waters Where They Have Been Introduced? A Re‐examination of Minnesota’s Stocked Muskellunge Waters

AbstractMuskellunge Esox masquinongy are large piscivores stocked into numerous lakes in North America, but the potential effects of these stockings remains poorly understood. To investigate potential fish community changes associated with Muskellunge stocking, we contrasted catch per unit effort (CPUE) for seven fish species commonly found in Minnesota, along with mean weight for two predator species, before and after Muskellunge introduction in 36 lakes with that of paired reference lakes. Because of the known importance of Cisco Coregonus artedi as prey for Muskellunge, we also examined these data by separating the lakes into those with and without Cisco. Across all 36 lakes, we observed several significant differences between stocked and reference lakes. Yellow Perch Perca flavescent CPUE in gill nets were significantly higher after Muskellunge were introduced, as was mean weight for Northern Pike Esox lucius. Gill‐net CPUE for Northern Pike and White Sucker Catostomus commersonii were both lower following Muskellunge introduction. When subsets of lakes with and without Cisco were considered, results for the 21 lakes without Cisco were similar to the results of the entire set of lakes. In the 15 lakes with Cisco, the only significant result was lower Northern Pike CPUE after Muskellunge stocking. Our results are evidence that the introduction and management of Muskellunge in these lakes has not adversely affected game fish populations.

Adult and larval fish assemblages vary among small tributary mouths of Green Bay, Lake Michigan

Small tributaries of the Great Lakes serve as important habitat during critical life stages of many fish species, though temporal and spatial dynamics of the assemblage that uses these systems are seldom investigated. This study quantifies larval and adult fish assemblages captured by fyke net and light traps among small tributary mouths of Green Bay, Lake Michigan. Ten tributaries harbored a total of 45 species representing 17 families, with the most abundant including spottail shiner (Notropis hudsonius (Clinton, 1824)) in adult assemblages and white sucker (Catostomus commersonii (Lacepède, 1803)) in larval assemblages. Larval fish assemblage structures differed over five biweekly sampling events in May and June. Adult fish assemblage structures varied among tributaries but not among spring, summer, and fall samples. Larval and adult species assemblages at these river mouths are likely influenced by hydrology, habitat structure, and species-specific ecology. Water movement may transport larvae into river mouths, as larval assemblages were dominated by species that spawn in coastal habitats. Adult species richness varied with longitude, with the greatest diversity in tributaries on the west shore. This investigation of fish assemblages highlights the spatial and temporal variation that occurs in these systems and their role in shaping fish populations in Green Bay.

Does ecological release from distantly related species affect phenotypic divergence in brook charr?

Ecological opportunity occurs when a resource becomes available through a decrease of interspecific competition and another species colonizes the vacant niche through phenotypic plasticity and intraspecific competition. Brook charr exhibit a resource polymorphism in some Canadian Shield lakes, where a littoral ecotype feeds mainly on zoobenthos and a pelagic ecotype feeds mostly on zooplankton. The objectives of this study were to test that (i) resource polymorphism is common in these brook charr populations, (ii) the presence creek chub and white sucker, two introduced species competing with brook charr for littoral resources, will decrease the phenotypic divergence between the two brook charr ecotypes, and (iii) the ecological release from introduced species will increase population and/or individual niche widths in brook charr. The study was based on 27 lakes and five indicators of resource use (stomach content, liver δ13C, muscle astaxanthin concentration, pyloric caecum length, and gill raker length). Our results indicate that within-lake differences in resource use by both ecotypes are common and stable through time. When facing interspecific competition, both littoral and pelagic brook charr incorporated more pelagic prey into their diet but maintained the amplitude of their differences in resource use, which contradicts our second prediction. Finally, we did not find any significant effect of introduced species on population and individual niche widths of brook charr. We suggest that the difference in feeding mode among distantly related competitors could prevent the complete exclusion of a species from a given niche and explain the lack of response to the ecological release.

Use of restored floodplains by fishes of the Middle Rio Grande, New Mexico, USA

AbstractNearly 1600 ha of habitat have been restored at 300 floodplain sites of the Middle Rio Grande (MRG), New Mexico, USA, as part of a cooperative effort of the Middle Rio Grande Endangered Species Collaborative Program to conserve the endangered Rio Grande silvery minnow (RGSM). These riverside sites are designed to inundate during spring run‐off and create ephemeral habitats for other aquatic and riparian species. This study of four restored floodplain sites in May–June 2017 found that of 14 fish species captured with fyke nets, common carp (41%), red shiner (32%), RGSM (16%) and white sucker (9%) dominated total numbers. Adult RGSM included 42% gravid females, 36% ripe males and 22% spent females, suggesting that this endangered species was spawning in and near these floodplains. Larval sampling also showed that restored sites and adjacent mainstem banklines were being used as nursery habitats, where RGSM larvae dominated six and nine species with 80% and 74% of total numbers, respectively. System‐wide proportions of RGSM larvae by phase suggest that larvae leave the floodplains and move to mainstem banklines beginning as late mesolarvae and metalarvae (14–22 days post‐hatch), and most depart by the juvenile stage. Altogether, 15 fish species were encountered in restored floodplain sites in 2017, compared to 16 species reported in concurrent annual mainstem monitoring. This study and others show that most fish species of the MRG move onto restored and natural floodplains equally in spring, and many use these habitats for spawning and as larval nurseries.

Long-Term Studies of Fish Health before and after the Closure of a Bleached Kraft Pulp Mill in Northern Ontario, Canada.

Changes in ecosystems after the removal of stress provide a rich source of information for conservation science. We used a long-term regional data set on the performance of white sucker (Catostomus commersonii) collected before and after the closure of a pulp mill to explore recovery in fish. Physiological indicators, including liver enzymes and plasma steroids, showed some compelling changes after the closure of the mill consistent with reduced exposure to pulp mill effluent but did not unequivocally demonstrate recovery. However, persistent signals in these fish may indicate effects of impoundment or discharge of sewage. We also used quantile regression with environmental covariates and bootstrap iteration to determine if systematic variation remained in relative body weight, liver weight, and gonad weight. In fish formerly exposed to pulp mill effluent, we found evidence of improvements (male gonad weight and liver weight of males and females), degradation (gonad weight of females), and no change (body weight). Although the observed patterns may be associated with closure of the mill, some differences were also found at regional locations, suggesting roles of additional stressors and challenging the clear association of change at the Mattagami River exposure site with the closure of the mill. However, fish captured at this location show responses consistent with regional locations, suggesting no residual impacts and highlights the challenges of identifying changes in fish even after large and known interventions. Environ Toxicol Chem 2021;40:162-176. © 2020 SETAC.

Behavioral responses of sea lamprey (Petromyzon marinus) and white sucker (Catostomus commersonii) to turbulent flow during fishway passage attempts

An understanding of how undesirable and desirable fish species respond behaviorally to turbulent flow in fishways would guide development of selective fish passage techniques. We applied high-resolution computational fluid dynamics modeling and competing risks analysis towards the development of predictive selective passage models. Sea lamprey (Petromyzon marinus; an invasive fish in the Great Lakes Basin, North America) upstream passage probability declined from 0.73 to 0.03 as flow conditions became increasingly turbulent, while declines in white sucker (Catostomus commersonii, a native fish in the region) upstream passage probability were less substantial (0.53 to 0.44). Deploying a sea lamprey trap in the fishway did not effectively reduce sea lamprey upstream passage probability, though capture rate increased during trials with cooler water temperature and low total kinetic energy. Bifurcated fishways that maintain low turbulent flow in the entrapment route and high turbulent flow in the upstream passage route could increase the effectiveness of trapping sea lamprey in fishways as a means to advance selective passage goals.

The Hematological Parameters of the Prussian Carp (Carassius gibelio, (Bloch, 1782)) Under the Zaporizhian (Dnipro) Reservoir Conditions

Hematological parameters are quite effective and informative for determining the health status of fish populations. They respond quickly to changes in habitats of different nature. The Prussian carp is one of the most widespread species in the Ukrainian reservoirs. Currently, the researches of hematological changes of this species in the modern conditions of the Zaporizhyian (Dnipro) reservoir are quite relevant. During the research the ecological classification of surface water quality in Ukraine, it was found that the water in the Samara Bay is characterized as "moderately polluted", and in the lower part of the reservoir it is "slightly polluted". The concentration of almost all investigated heavy metals in the water of the Samara Bay is higher compared to the lower part of the reservoir. The number of erythrocytes and hemoglobin content in the blood of Samara Bay fish were lower by 22.4% and 44%, respectively, compared to fish in the lower part of the Zaporizhian (Dnipro) reservoir, and the erythrocyte sedimentation rate was higher by 81.8%. In the Prussian carp from the silver Zaporizhian (Dnipro) reservoir, neutrophilic leukocytosis with a shift to the left was observed, which is usually characteristic of inflammatory processes and various intoxications. There were also statistically significant deviations in the activity of ALT and AST in the blood plasma of fish in the Samara Bay, which may indicate a chronic impact of a complex of anthropogenic factors on fish, especially on the function of the liver, which serves as a detoxifying organ.

Mercury bioaccumulation in stream fish from an agriculturally-dominated watershed

Bioaccumulation of mercury in freshwater fish is a complex process driven by environmental and biological factors. In this study, we assessed mercury in fish from four tributaries to the Red Deer River, Alberta, Canada, which are characterized by high surface water mercury concentrations. We used carbon (δ13C) and nitrogen (δ15N) stable isotopes to examine relationships between fish total mercury (THg) concentrations, food web dynamics and patterns in unfiltered THg and methylmercury (MeHg) concentrations. We found that THg concentrations exceeded the tissue residue quality guideline for the protection of wildlife consumers in 99.7% of fish sampled. However, while the surface water THg concentration was highest in Michichi Creek and the MeHg concentration was consistent across streams, patterns of fish THg concentrations varied depending on species. Furthermore, body size and trophic level were only correlated with THg concentrations in white sucker (Catostomus commersoni) and Prussian carp (Carrasius gibelio). The results of this study suggest that mercury poses a risk to the health of piscivorous wildlife in the Red Deer River watershed. Despite high THg concentrations in these streams, mercury bioaccumulation is not driven by environmental inorganic mercury concentrations. Additionally, commonly cited factors associated with mercury concentrations in fish, such as body size and trophic level, may not strongly influence bioaccumulation in these stream ecosystems.

Baseline white sucker health and reproductive endpoints for use in assessment of further development in the alberta oil sands

Baseline white sucker health and reproductive endpoints for use in assessment of further development in the alberta oil sands

Long-term variations in fish community structure under multiple stressors in a semi-closed marine ecosystem in the South China Sea

Daya Bay is an ecologically and economically crucial semi-closed bay along the southern coast of China. It is proven to be a stressed ecosystem and therefore obviously vulnerable to further extrinsic disturbance. This study used fish data from bottom-trawl surveys, conducted from 1985 to 2018, to analyze variations in the fish community structure over the past 30 years. The results showed that warm-water fish species were overwhelmingly dominant during all years, suggesting the bay's tropical to subtropical characteristic. By 2015, the number of fish species had decreased by 29.44% of that caught in 1987, moreover, values of the Shannon–Wiener diversity index and the Margalef richness index were lower in 2015 compared to 2004. There were evident shifts in the fish community composition from pelagic to demersal species, as suggested by the dominant species found in springtime, the dominant families, and percentages denoting the numbers of species in the main orders. Average fish body weight in landings declined from 13.4 g to 7.58 g, the body sizes of four typical commercial fish species decreased by varying degrees over the last 30 years. Abundance–biomass comparison curves suggested that the Daya Bay fish community was more stressed in 2015 than in 2004 during all seasons, except winter. In general, the fish community structure in Daya Bay is consequently in an unsteady state. Multiple anthropogenic disturbances, such as fishing (including overfishing and changes in the main fishing gears), the destruction of natural habitats, pollutants, and anthropogenically induced temperature changes, are likely to have caused obvious shifts in the bay's fish community structure. Therefore, we emphasize the need for integrating management of multiple anthropogenic stressors to achieve ecosystem-based management.

Suitability of surgically implanted 8‐mm passive integrated transponder tags for small‐bodied fishes

Innovative tools that benefit conservation are critical as freshwater fishes are lost at unprecedented rates. Mark-recapture methods can characterize population demographics and life-history traits of diverse fishes, but suitable techniques for tagging for individual recognition of small-bodied fishes are rare. Passive integrated transponder (PIT) tag technology may facilitate the tagging of small fishes and early life stages of larger species. However, relatively little research has evaluated the suitability of these small (8.4 × 1.4 mm) tags for many groups of small fishes. Tag loss (retention and survival) and growth of individuals implanted with PIT tags relative to control and sham treatments were compared for eight fishes of differing morphologies. Additionally, the utility of cyanoacrylate to improve tag retention was tested on a subset of taxa. Fish of each species were equally divided and randomly assigned to one of three treatment groups (handled [control], surgical incision [sham], or surgical incision and PIT tag implantation [PIT]). During the 42-d study period, mortalities and expelled tags were counted daily and growth was measured weekly. Researchers can generally expect little tag loss and uncompromised growth rates for a variety of small-bodied fishes; however, initial fish length was related to the magnitude of physiological effects for some taxa (i.e., blacknose dace Rhinichthys atratulus, johnny darter Etheostoma nigrum, juvenile white sucker Catostomus commersonii). Relatively poor survival (<80%) was observed for two benthic species: johnny darter and blacknose dace, often when incision wounds became inflamed before healing. Prevalent tag loss for johnny darter, tadpole madtom Noturus gyrinus, and a dorsal-laterally compressed cyprinid can be reduced by closing the wounds with cyanoacrylate, but with substantially increased mortality rates. This research demonstrates the broad applicability of PIT tagging technology for ecological studies of small-bodied fishes and alleviates many concerns when surgically implanting tags into several fishes.

Juvenile fish assemblage recruitment dynamics in a mid-Atlantic estuary: before and after Hurricane Sandy

Hurricanes can have long-term effects on estuarine fauna. Understanding these effects is important as climate change may influence the severity and frequency of these storms. On 29 October 2012, Hurricane Sandy, a large storm spanning roughly 1850 km in diameter, made landfall in Brigantine, New Jersey (USA), approximately 20 km south of Barnegat Bay, during an ongoing study of the bay’s ichthyofauna, providing an opportunity to observe fish recruitment dynamics coincident with hurricane passage. The objective of this study was to measure variance in the Barnegat Bay pre-Sandy fish assemblage relative to that of 1 and 2 yr after the storm. Barnegat Bay fishes were surveyed with an extensive otter trawl study in April, June, August, and October of 2012 (pre-Sandy), 2013 (1 yr post-Sandy), and 2014 (2 yr post-Sandy). Species composition of the fish assemblage was similar across years. Analyzed structural characteristics (abundance, diversity, richness) of the fish assemblage were occasionally more likely to occur or were larger pre-Sandy and 2 yr post-Sandy relative to 1 yr post-Sandy, but this trend was inconsistent across seasons and between structural characteristics. Furthermore, odds of occurrence and length frequency distributions for many resident species and sentinel fall/winter spawners did not indicate that variance could be definitively explained as a hurricane effect. The capability of fish to relocate from areas of temporarily unsuitable habitat and annual new recruitment of larvae and juveniles to the bay likely contributed to the observed stability in the fish assemblage.

Development of a thin-film solid-phase microextraction (TF-SPME) method coupled to liquid chromatography and tandem mass spectrometry for high-throughput determination of steroid hormones in white sucker fish plasma.

Steroid hormones (SH) play a number of important physiological roles in vertebrates including fish. Changes in SH concentration significantly affect reproduction, differentiation, development, or metabolism. The objective of this study was to develop an in vitro high-throughput thin-film solid-phase microextraction (TF-SPME)-liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for targeted analysis of endogenous SH (cortisol, testosterone, progesterone, estrone (E1), 17β-estradiol (E2), and 17α-ethinylestradiol (EE2)) in wild white sucker fish plasma where the concentrations of the analytes are substantially low. A simple TF-SPME method enabled the simultaneous determination of free and total SH concentrations. The use of biocompatible coating allowed direct extraction of these hormones from complex biological samples without prior preparation. The carryover was less than 3%, thereby ensuring reusability of the devices and reproducibility. The results showed that TF-SPME was suitable for the analysis of compounds in the polarity range between 1.28 and 4.31 such as SH at different physicochemical properties. The proposed method was validated according to bioanalytical method validation guidelines. The limit of detection (LOD) and limit of quantification(LOQ) for cortisol, testosterone, progesterone, E1, E2, and EE2 were from 0.006 to 0.150ng/mL and from 0.020 to 0.500ng/mL, respectively. The recovery for the method was about 85%, and the accuracy and precision of the method for cortisol, testosterone, and progesterone were ≤ 6.0% and ≤ 11.2%, respectively, whereas those for E1, E2, and EE2 were ≤ 15.0% and ≤ 10.2%, respectively. On the basis of this study, TF-SPME demonstrated several important advantages such as simplicity, sensitivity, and robustness under laboratory conditions. Graphical abstract.

Effects of White Sucker Removal and Stocking on Growth of Fishes in Northern Lakes

AbstractContinued management interest in using White Sucker Catostomus commersonii population manipulations to improve the growth of Northern Pike Esox lucius and potentially competing panfish species provided an opportunity to evaluate White Sucker removal and supplementation in Michigan lakes. Overabundant White Suckers from one lake were transferred into two lakes where higher populations were desired, with fish growth responses being evaluated in each lake and in a control lake pretransfer and at 5 years posttransfer. Criteria for project success were (1) continued low abundance of White Suckers in the removal lake and increased abundance in the recipient lakes; (2) positive growth response of panfish species to White Sucker removals; and (3) positive growth response of Northern Pike to White Sucker additions. After 5 years, White Sucker population abundance and recruitment patterns showed continued survival of stocked adults but little recruitment in stocked lakes and the fish species examined showed no clear positive growth responses to White Sucker manipulations. Fishery managers should carefully consider the costs and benefits of using White Sucker manipulations as a management tool.

Regional and Long‐Term Analyses of Stable Isotopes of Fish and Invertebrates Show Evidence of the Closure of a Pulp Mill and the Influence of Additional Stressors

A bleached kraft pulp mill discharging effluent to the Mattagami River in northern Ontario, Canada, closed after almost 90 yr of operation. During its operation, effluent from the mill influenced biota in the downstream areas. To assess shifts in the reliance of biota from mill-derived nutrients, the isotopic composition (δ13 C and δ15 N) of white sucker (Catostomus commersoni) muscle and whole mayflies (Hexagenia sp.) were compared before (1990s) and after the pulp mill's closure (2012-2014). To better understand other potential sources of spatial and temporal change, samples from 3 other tributaries in the basin with dams, ongoing pulp mill operations, sites receiving sewage, and at several reference sites were collected and compared. Irrespective of time period, biota collected at sites downstream of both dams and active pulp mills tended to have elevated δ13 C values, but variable changes in δ15 N (negligible in most cases) when compared with upstream samples. The isotopic composition of mayflies varied at reference sites over time, with decreasing values of δ13 C and δ15 N (mayflies only) with increasing depth, and there was evidence of lower δ13 C in fish after the pulp mill closure. Overall, these results suggest the importance of long-term, regional-scale measurements for documenting the effects of stressors on nutrient use by aquatic species. Environ Toxicol Chem 2020;39:1207-1218. © 2020 SETAC.

Detecting aquatic invasive species in bait and pond stores with targeted environmental (e)DNA high-throughput sequencing metabarcode assays: Angler, retailer, and manager implications

Bait and pond stores comprise potential, yet poorly understood, vectors for aquatic invasive species (AIS). We tested for AIS and illegal native species in 51 bait and 21 pond stores from the central Great Lakes (Lake Erie, Ohio and Lake St. Clair, Michigan) and the adjacent Wabash River (Indiana) using environmental DNA (eDNA) metabarcode assays of water samples and morphological identifications. Retailers were questioned about supply chains, and anglers surveyed about baitfish use and disposal. Assays revealed unadvertised species eDNA in 100% of bait stores, with 61% containing illegal native non-bait (totaling 13 species) and 88% having AIS (11 species). Illegal native non-bait species included juvenile walleye, yellow perch, and white sucker eDNA. AIS eDNA included Eurasian ruffe in seven stores (all states), silver carp in five (including a Lake Erie store in two separate years), and bighead carp in two Lake Erie stores that also had silver carp. Among pond stores, two in Lake St. Clair had bighead carp eDNA, one also contained silver carp, and a Wabash River location showed European ide. Unadvertised invasive snails were discerned in 55% of pond stores. Four contained zebra mussel eDNA and two had invasive bryozoans. Illegal native species and AIS were widespread, but showed little relationship to the retailers' variable and extensive supply chains. Live baitfish releases were reported by 50% of Lake Erie anglers and 35% in Lake St. Clair. Consumer behavior and AIS prevalence in the bait and pond trades thus pose serious risks for introductions and spread.

RELAÇÕES SOCIOAMBIENTAIS NAS ÁREAS DE MANGUEZAIS NA CIDADE DE MAGÉ NO ESTADO DO RIO DE JANEIRO

O presente trabalho teve por objetivo relatar as relações socioambientais do manguezal de Magé, município da Baixada Fluminense, localizado ao fundo da Baia de Guanabara. Torna-se necessário a divulgação das ações que retrocederam os obstáculos socioambientais, como a poluição e a competição por terras anteriormente utilizadas para a pesca artesanal e, atualmente, dominada pela ação de grandes empreendimentos industriais. Recuperou-se informações, sobretudo, do acidente ecológico que ocorreu em 18 de janeiro de 2000, sendo este o maior da história do país com o vazamento do duto da PETROBRÁS que liga a Refinaria Duque de Caxias (REDUC) ao seu terminal da Ilha D´Água. Com isso, foram despejados 1,3 milhões de m³ de óleo e graxa nas águas da Baía de Guanabara. Este acidente foi um marco no declínio das atividades pesqueiras desta Baía, conforme citado pela literatura. A região mais afetada é o chamado fundo da Baía, que fica entre os bairros do Caju, Ramos, Ilha do Governador e de Magé. Foi relatado os fatores que possibilitaram a degradação deste ecossistema marinho, assim como construída uma sinopse das principais peculiaridades desse ecossistema e os conflitos socioambientais ocorridos nas áreas de manguezais localizadas no município de Magé. Por estar incorporado em uma dinâmica urbana o ecossistema é afetado pelos impactos desta sociedade e também interfere no cotidiano da população local. Medidas de proteção e restauração foram adotadas para resgatar o ecossistema, como os movimentos sociais e a ação individual do reflorestamento e recuperação das áreas dos manguezais afetadas, seja por interesses econômicos, visto que fornecia madeira, a fauna destinada a pesca e catação de crustáceos, ou pela ocupação das cidades e aterros sanitários.