bluuebunny/crossref_metadata_2025 huggingface dataset:
The intriguing dynamics of Rastrineobola argentea fishery in the Kenyan waters of Lake Victoria
Authors: Ojwang W. O. , Ojuok J. E. , Nyamweya C. , Agembe S. , Owili M. , Yongo E. , Wakwabi E. O.
Published: October 2017

The Lake Victoria ecosystem once hosted a diverse fish community dominated by a large species flock of haplochromine cichlids. Today this fish assemblage is highly altered by anthropogenic activities, with at least half of the indigenous species either extinct or very rare. The fishery has been reduced to three fishes of economic importance: introduced Nile Perch (Lates niloticus) and Nile Tilapia (Oreochromis niloticus), and Indigenous Minnow, Rastrineobola argentea, locally known as Omena. Decline in fish stocks in the lake is still continuing; however, in order to rejuvenate stocks therein, a fishing ban (closed season) was imposed in November, 2001 between 1 April and 31 July of each year through a Kenyan government gazette and legal notice (L.N.214/2003). The ban was not only intended to protect the Omena fishery but was also used to anchor efforts towards protecting and rejuvenating dwindling stocks in the lake. However, whether the Kenyan approach has made any gains for the region is still equivocal. It is on this basis that we reviewed existing information on both historical and current stock levels of R. argentea, and the closed fishery implication on the livelihoods of the riparian communities. Our review results indicate that Omena biomass in Lake Victoria has increased considerably from approximately 500,000 MT in 2001 to 911,328 MT in 2011. Rastrineobola argentea is now the most important fish stock by mass in Kenyan waters contributing almost 61.5% of the total fish landings (10,339.0 MT), with ex-vessel value of total fishers’ earnings of about Kshs. 207 million (approx. USD 2.5 million). In response to the emerging uncertainties regarding the closed season or ban, we recommend and advise for a balanced, win-win approach balancing the biological cycle of stocks against the socio-political and economic issues, in order to sustain the stocks and enable the fisher folks to eke their daily food and earnings.
Lake Tanganyika fisheries in post-conflict Democratic Republic of Congo
Authors: Van der Knaap M. , Kamitenga D. Manara , Many L. Ngoie , Tambwe A. Esube , De Graaf G. J.
Published: October 2017

Since the first regional lakewide fisheries frame survey on Lake Tanganyika in 1995, no fisheries census was conducted in the Democratic Republic of Congo and therefore the results of the second lakewide frame survey in 2011 should be studied intensively as numerous changes took place in the region in general and along the Congolese coastline in particular. In the capital city, Kinshasa, at a distance of approximately 2000 km from the lake, Lake Tanganyika is known as the water body where the fish die of old age according to Gayo Lemba, Chairman of the Lake Tanganyika Authority Management Committee for Democratic Republic of Congo from a personal communication. The results of the 2011 frame survey indicate that fish were not allowed to reach an old age as the fishing capacity over time had more than doubled as compared to the situation in 1995. The fisheries resources were considered under high pressure by the end of the previous millennium and therefore a Framework Fisheries Management Plan was developed by Food and Agriculture Organization of the United Nations to start managing the fisheries (both fish and fishermen) with a view to a regional lakewide approach involving the neighboring riparian countries. The present article describes the major findings of the frame survey along the littoral zone of Democratic Republic of Congo in 2011 in comparison with the results from the first lakewide regional frame survey in 1995. Not only fishermen increased in number, but also fishing canoes and women processors as well as traders. The approach taken by Democratic Republic of Congo, involving a new sort of co-management, contributes to peace, development and relative stability in this fragile region.
Dynamic evaluation on ecosystem service values of urban rivers and lakes: A case study of Nanchang City, China
Authors: Liu Yaobin
Published: October 2017

Urban rivers and lakes play a significant role in providing ecosystem services, such as water supply, purification, nutrient retention, recreation, aesthetics, and more. However, there is no widely-accepted methodology for how to dynamically evaluate the ecosystem service values of urban rivers and lakes. Using data from survey and remote sensing of Nanchang City, China, this article constructs a conceptual framework based on the Millennium Ecosystem Assessment to propose an integrated approach to evaluate the ecosystem service values of urban rivers and lakes. Furthermore, the article employs a GIS-based Markov chain model to predict the future probable distribution pattern of land use in Nanchang City, while it uses an artificial neural network model to simulate the potential changing of ecosystem service values. The Millennium Ecosystem Assessment-based dynamic evaluation shows that in the first period of 1989–1999, provisioning services are dominant, followed by regulating services, supporting services and cultural services, while during the second period of 1999–2008, regulating services rank firstly in the total change of ecosystem service values, followed by supporting services, cultural services and provisioning services. The artificial neural network-based simulation indicates that the total will slightly increase in line with a small undulation in regulating service values, whilst the most changes brought by the provisioning services will be stable. This study is intended to serve as a tool to be used in decision making for proper and informed urban aquatic ecosystem management.
The analysis of phytoplankton blooms off the Yangtze River Estuary in the spring of 2007
Authors: Fu Dongyang , Pan Delu , Wang Difeng , Zhang Ying , Ding Youzhuan , Liu Dazhao
Published: October 2017

The Yangtze River Estuary and the Zhejiang coastal waters have a high incidence of spring phytoplankton bloom and even red tide, but there are rarely phytoplankton blooms in the open waters off the Yangtze River Estuary in the spring considering its relative oligotrophy. From 25 April to 7 May 2007, two strong phytoplankton blooms were observed in the open sea area (the east by 125° E-box C), and the chlorophyll-a concentration, whether measuring through remote sensing or in situ, consistently indicated bloom characteristics. Chlorophyll-a concentration in this area increased significantly, even up to 11 mg·m−3 at individual stations during this period. Average chlorophyll-a measured by remote sensing in region C (125–127°E, 30–32°N) was 2.07 mg·m−3, while the climatic average was only 0.97 mg·m−3 during 2000 to 2008. Analyses demonstrated that suspended sediment concentrations had almost no change, but a slight decrease occurred during the two blooms periods as well as low nitrate and phosphate and higher silicate and salinity in box C. It was suggested that the increased chlorophyll-a concentration was not caused by the intrusion of dilute water from the estuary with high suspended sediment concentrations and nutrients, but probably due to local strong winds on the night of 26 April to the morning of 27 April. A further study with profile data of chlorophyll-a, temperature, salinity and other parameters indicated that strong mixing by the local wind was the main reason for the blooms.
Increasing algal biomass in Lake Vänern despite decreasing phosphorus concentrations: A lake-specific phenomenon?
Authors: Weyhenmeyer Gesa A. , Broberg Nils
Published: October 2017

Algal blooms in lake waters are frequently associated with elevated nutrient levels, in particular phosphorus. Here we show, with long-term data from Sweden’s largest lake, Lake Vänern, that total phytoplankton biomass has significantly increased since the 1980s at the same time as total phosphorus and inorganic nitrogen concentrations have significantly decreased (non-parametric Mann-Kendall test: P < 0.01). Lake Vänern was not the only lake showing such a pattern: evaluating long-term data from 13 small oligotrophic reference lakes revealed the same pattern. Other synchronous changes observed in Sweden’s oligotrophic lakes included strongly decreasing sulfate concentrations and increasing water temperatures. We found that alkalinity, water temperatures, silica and sulfate concentrations were the strongest predictors for total phytoplankton biomass at all three sites in Lake Vänern when we used partial least squares regression models with 11 input variables. From our results, we suggest that decreasing acidity in combination with increasing water temperatures has been more important for phytoplankton growth than total phosphorous and nitrogen concentrations. Thus, we conclude that phytoplankton biomass in oligotrophic small and large lakes is strongly associated with climate and atmospheric depositional changes, and consequently needs to be managed beyond catchment scales.
The Laurentian Great Lakes in transition: A chronicle of research at the base of the foodweb
Authors: Munawar M. , Munawar I. F. , Fitzpatrick M. , Niblock H. , Lorimer J.
Published: October 2017

A unique science and management strategy has been developed for the Laurentian Great Lakes due to their enormous size, geographic-ecological diversity, political and economic importance. This article is a documentary of more than 40 years of research conducted at the base of the foodweb by Fisheries and Oceans Canada, which has contributed significantly to the management of the Great Lakes. In the 1960s, the governments of Canada and the United States responded to the threat of cultural eutrophication which eventually resulted in the signing of the binational Great Lakes Water Quality Agreement. Dr. R. A. Vollenweider and Dr. J. R. Vallentyne were instrumental in developing a phosphorus abatement program, as well as the adoption of the “ecosystem approach” resulting in an holistic and integrated protocol for managing multiple environmental stressors. By showcasing some selected examples (Lake Ontario, Bay of Quinte, current research activities), an attempt is made to chronicle the evolution of phytoplankton, primary productivity and microbial foodweb research in the Great Lakes. Some of the research programs, techniques, models, policies and international cooperation are highlighted, in addition to the strong European influences on Great Lakes research. The lessons learned from the long-term Great Lakes research experience could be extrapolated and applied to enhance understanding of the ecology and management of other large lake ecosystems throughout the world.
Stakeholder involvement in data collection: Shall we get the same desired results?
Authors: Mbewe Mbamwai
Published: October 2017

The fishing industry in Zambia benefits over 1 million people both directly and indirectly, and monitoring of fish stocks and players involved in the actual fishing remains a great priority. In light of the high costs surrounding critical, but basic fisheries data collection on the part of the Department of Fisheries, consideration had to be given to assess whether data collected by Fishing Village Management Committees dotted along the shoreline of Lake Kariba and shared or discussed at scheduled quarterly meetings, was reliable and could therefore be used in planning or policy decisions.

The village committees hold regular meetings, receive new fishers and fish traders joining their villages and report changes in fisher and boat numbers by type and challenges. The secretariat is formed by the Department of Fisheries at the district level in a given fishery. Lakewide frame surveys are conducted once every five years by the Department. Mean values of the datasets from two strata were subjected to a student t-test in order to ascertain deviation and reliability.

It was determined that data collected by village committees was reliable and could be used with confidence for planning departmental teams.
An overview of thirty years of research on ballast water as a vector for aquatic invasive species to freshwater and marine environments
Authors: Bailey Sarah A.
Published: October 2017

Ballast water has been widely used by commercial vessels to control trim, draft and stability since the late 1870s. While the global transport of ballast water (and associated sediments) was first recognized as a potential dispersal mechanism for plankton in the late 1890s, quantitative research on the issue does not appear in the primary scientific literature until the mid-1980s. Following James T. Carlton's comprehensive review of the biology of ballast water in 1985, there was an explosion in research effort, with nearly 400 papers published in the last thirty years. This article provides a brief overview of the role that ballast water has played as a global vector for aquatic invasive species, summarizing the current state of ballast water research and emerging topics for future study, based on a review of articles in the primary scientific literature.

Initially, the main research focus was to document the community composition of ballast water in ships arriving to ports around the world. In the late 1990s, risk ssessments examining shipping traffic patterns and environmental tolerances of species likely transported in ballast water dominated. By 2000, ballast water studies examining efficacy of various treatment strategies dominated, and papers exploring new tools and methods for more accurate/representative sampling and analysis of ballast water emerged as an important research topic. There is currently insufficient data to confidently quantify the probability of invasion associated with any particular inoculum density (or discharge standard), as a result, laboratory, field and modeling studies examining the relationship between invasion risk and the size of the initially released population (the ‘risk-release relationship’) are an emerging, high priority field of study.
Abundance of harmful algal blooms in the coastal waters of Oman: 2006–2011
Authors: Al-Azri Adnan R. , Al-Hashmi Khalid A. , Al-Habsi Harub , Al-Azri Nasser , Al-Khusaibi Salim
Published: October 2017

Over the last decade, the ecosystem of the Sea of Oman and Arabian Sea has been showing signs of rapid and profound changes in terms of phytoplankton diversity and harmful algal bloom outbreaks. Frequent blooms have been on the rise in the coastal waters of Oman causing adverse impacts on marine life. The population dynamics of potentially harmful phytoplankton in relation to environmental parameters was investigated from June 2006 to April 2011. Our studies recorded 24 potentially harmful species. Dinoflagellates Prorocentrum minimum, Scrippsiella trochoidea, Cochlodinium polykrikoides and Noctiluca scintillans were the most abundant species. Diatoms Pseudo-nitzschia seriata, Climacodium frauenfeldianum and Guinardia flaccida were the most abundant, but occurred at low concentrations. Scrippsiella trochoidea and Noctiluca scintillans were reported previously as common phytoplankton in Oman coastal waters; however, Prorocentrum minimum and Cochlodinium polykrikoides are reported for the first time. Here we report their occurrence and persistence in relation to changes in environmental parameters. In addition, the potential long-term implications of changes in phytoplankton species and harmful algal blooms outbreaks on ecological, economic, social and human health impacts will be discussed.
Suspected ballast water introductions in the Arabian Gulf
Authors: Al-Yamani Faiza Y. , Skryabin Valeriy , Durvasula Subba Rao V.
Published: October 2017

The Arabian Gulf is a unique hypersaline semi-arid environment. About 53,000 ships visit the Gulf annually for oil transportation. The potential for introduction of alien species via ships' ballast water discharge is significant. Fish kills have been associated with massive blooms of the dinoflagellates Cochlodinium polykrikoides in the Sea of Oman, Karenia (Gymnodinium) selliformis, Heterosigma akashiwo off Kuwait and the appearance of these causative algae were first time recordings for this region. Although systematic studies of biota have revealed several first time recordings, based on their geographical distribution, we identified 14 species, ranging from microalgae to fish, as suspect alien introductions. Microalgae from ballast water need be cultured to establish their survival under the harsh environmental conditions of the Gulf and screened for phycotoxins. There is a strong need for maritime awareness on the ballast water problem and to implement ballast water management regulations in the Arabian Gulf consistent with International Maritime Organization (IMO) regulations and legal instruments.
Fish diversity and fisheries in the Caspian Sea and Aral–Syr Darya basin in the Republic of Kazakhstan at the beginning of the 21st Century
Authors: Mitrofanov I. V. , Mamilov N. Sh.
Published: October 2017

For many years fishing was one of the most important human activities in the Caspian Sea and Aral-Syr Darya basin. This article summarizes the results of research conducted by the authors during 1991–2010. Drastic shifts in commercial fish catches as well as in fish diversity were revealed for both the Caspian Sea and the Aral-Syr Darya areas as a result of overfishing, poaching, exotic species introduction, and habitat alterations. The policies of the government authorities in the field of nature protection, especially those involving fish resources, may be characterized by the adoption of controversial and inconsistent decisions and subsequent restructuring of those state institutions charged with nature protection that resulted. These policies did not promote sustainable use of nature resources and will have long-lasting impacts on the protection of fish and other aquatic biological resources. Some recommendations are provided for attaining sustainable fisheries management in the North Caspian and Aral regions.
Environmental conditions, freshwater fishes and fishery management in the Ukraine
Authors: Movchan Yuriy V.
Published: October 2017

Ukraine, with a total area of almost 604,000 km2, has 73,000 rivers and streams and about 20,000 lakes and estuaries. These aquatic resources belong to the Baltic Sea and the Black Sea (including the Sea of Azov) basins, and are inhabited by at least 137 fish species. Over the last 40–50 years, the freshwater fish fauna of Ukraine waters has changed considerably. Intensive fishing based on non-biological principles in the absence of aquaculture assistance caused significant degradation of fish populations: in particular, the replacement of long-life cycle species by short-life cycle species and “biological pollution” as a result of intentional and unintentional introductions. Twenty new exotic species were introduced and some of them became established. At the same time, a number of long-life cycle and migratory fishes, which were the most important for commercial fisheries, became extirpated. However, the growing number of nature reserves of different levels and categories gives some reasons to hope for stabilization of fish diversity in general and its possible improvements in the future. The freshwater fishery needs further modernization based on advanced principles that could guarantee a sustainable use of freshwater fish resources.
Assessment of fish species assemblage on mesohabitat scale: A case of middle stretch of Narmada River, India
Authors: Naskar Malay , Sahu S. K. , Sharma A. P.
Published: October 2017

In river ecosystems, mesohabitat characteristics (i.e. pool, run, riffle, rapids, etc.) act as proximate variables to fish species occurrence. Fish occurrence and mesohabitat data are very often collected independently for different purposes, which invites challenges to characterize the fish species distribution pattern on mesohabitat scale. The present article delineates quantitative assessment of fish occurrence in relation to mesohabitat using secondary data. Middle stretch of the Narmada River of India has been selected for the study. Geographic information system tools have been used for integration of species and mesohabitat data. Nonmetric multidimensional scaling, cluster analysis and analysis of similarity techniques have been used for similarity analysis. Logistic regression model has been applied for model-based inferences on family-mesohabitat relationship. Two separate mesohabitat types, viz., Pool-Run and Run-Riffle, have been characterized by the fish species occurrence pattern. Dissimilarity of fish species composition between Pool-Run and Run-Riffle was statistically significant (p-value < 0.05). The family-mesohabiat model predicted that the occurrence probability of a fish species was 14.49 times more in the Pool-Run than that in the Run-Riffle. The predictive accuracy of the model was 69.8%.
Algal growth potential and oxidative stress in Ankistrodesmus falcatus exposed to waters from Xochimilco Lake system, México
Authors: Abeja-Pineda O. , López-López E. , Favari L. , Sedeño-Díaz J. E.
Published: October 2017

The aim of this study was to assess the toxic effect of the water of Xochimilco Lake on a native microalgae species of the first trophic level, Ankistrodesmus falcatus. We evaluated oxidative stress (lipid peroxidation, and antioxidant activity of the enzymes: superoxide dismutase, catalase and glutathione peroxidase), and algal growth of A. falcatus, when exposed in bioassays to waters from three zones of Xochimilco Lake (urban, tourist, and agricultural), in four study periods; the responses were compared with those of a batch control. Water quality shows serious deterioration in the Xochimilco Lake system. Biomonitoring with biomarker responses provided information about the spatio-temporal impact of pollution on A. falcatus. Water samples of the three study zones of Xochimilco Lake induced oxidative stress in A. falcatus, and impaired its antioxidant enzymes and algal growth responses. Alteration detected in algal growth and oxidative stress of A. falcatus when exposed to waters from all sites and study periods make evident the toxic effect of the water from the Xochimilco Lake system.
Seasonal flux variability of planktonic foraminifera during 2009–2011 in a sediment trap from Xisha Trough, South China Sea
Authors: Xiang Rong , Liu Jianguo , Wang Dongxiao , Chen Muhong , Han Chen , Chen Zhong , Yan Wen , Tang Shilin
Published: October 2017

The flux and seasonality of planktonic foraminifera were studied through a time-series sediment trap deployed in the Xisha Trough, South China Sea from June 2009 to August 2011. The general flux pattern for planktonic foraminifera showed high values during the winter half-year/season (from late September/October to February) and low flux during the rest of the year. This flux pattern contrasts with the bimodal pattern in the central and southern South China Sea, which shows two high flux peaks corresponding to the prevailing summer and winter monsoon periods, respectively. Apparent interannual flux differences, which may be related to the climate change from an El Niño year to a La Niña year, were observed. Monsoonal driven seasonality is most prominent in Pulleniatina obliquiloculata, Neogloboquadrina dutertrei and Globigerina bulloides, with over 80% of their species-specific fluxes (93% for G. bulloides) occurring from late September/October to February. Globigerinoides sacculifer and Globigerinoides ruber show similar seasonality, generally following the trend of the total flux of planktonic foraminifer. G. bulloides may have the potential to be developed as a winter proxy-species. Globigerinoides conglobatus mostly appears in June to August and can be developed as a summer proxy-species.
A study on water quality and trophic state of Akgöl Lagoon (Mersin, Turkey)
Authors: Alp Mehmet Tahir , Fakioğlu Yunus Emre , Özbay Özgur , Koçer Mehmet Ali Turan
Published: October 2017

This study aimed to determine the physicochemical characteristics of the water quality and trophic state of Akgöl Lagoon located in the eastern Mediterranean. Cluster analysis clearly revealed the spatial heterogeneity classifying sampling stations as saline and freshwater/brackish water sites. A multivariate analysis of variance followed by principal component analysis supported that salinity was major factor affecting physicochemical water quality variations in the lagoon. As salinity was mainly governed by freshwater inflows depending on agricultural irrigation, it can be proposed that water quality was significantly influenced from freshwater use by human activities. The parameters used as predictors (total nitrogen, total phosphorus, chlorophyll a and Secchi disk transparency) yielded different trophic states for the lagoon. However, as chlorophyll is a better predictor than the other indices, it was concluded that the Akgöl Lagoon is at mesotrophic status.
Periphyton responses to nitrogen and phosphorus enrichment of shallow lake systems dominated by submerged plants: A mesocosm study
Authors: Mei Xueying , Zhang Xiufeng
Published: October 2017

The responses of periphyton to enrichment with nitrogen and phosphorus have been investigated in shallow lakes with low macrophyte biomass, but less is known about shallow lakes dominated by submerged plants. We examined the biomass and species composition of periphyton in 12 mesocosms dominated by Vallisneria natans (Lour.) Hara and subjected to different nitrogen and phosphorus enrichment regimes. Periphyton biomass measured as Chlorophyll a (Chl a) was higher in the nitrogen-enriched treatment relative to the controls. Chl a initially increased with phosphorus and nitrogen + phosphorus enrichment, but declined towards the end of the experiment. This delayed negative response of periphyton to nutrient enrichment appeared to be due to increased phytoplankton concentrations which inhibit light availability (nitrogen + phosphorus additions) and to increased growth of V. natans (phosphorus additions). Shifts in species composition of periphyton also occurred with different treatments. Our work demonstrated that periphyton are significantly affected by enrichment with nitrogen and phosphorus, and helped clarify the ecological role of these important primary producers.
Implications of climate warming for hydrology and water balance of small shallow lakes: A case of Wamala and Kawi, Uganda
Authors: Natugonza Vianny , Ogutu-Ohwayo Richard , Musinguzi Laban , Olokotum Mark , Naigaga Shamim , Kitabona Janet
Published: October 2017

Climate variability and change that have been intensifying since the 1970s are accompanied by changes in hydrology and water balance of inland aquatic systems. These changes, however, have not been well documented with regard to small and shallow aquatic systems that are more vulnerable. Changes in temperature, rainfall and wind speed around Lakes Wamala and Kawi (Uganda) were examined to provide insight on how the increasing variability and change in climate affect water balance and lake water levels. Around Lake Wamala, average air temperature has increased by 0.018°C y−1 since 1980. Rainfall increased by 9.01 mm y−1 since 1970 and accounted for 79.5% of the water gain during 2011 and 2013 period. However, the gains were exceeded by losses as a result of evaporation that accounted for >85% of the water loss. Despite the increase in rainfall, the mean lake depth of Lake Wamala decreased by 0.015 m y−1, apparently due to high evaporation rates. Around Lake Kawi, average air temperature has increased by 0.036°C y−1 since 1980. Rainfall, however, has decreased, although it still dominates the water inflows, accounting for 83% of the total water gains. Interviews with local fishermen on Lake Kawi indicated that the lake shoreline has receded by ∼50 m over the last two decades. These results suggested that most of the water in small shallow lakes is gained through direct rainfall, but more is lost through evaporation. Therefore, increase in rainfall around these lakes is no longer sufficient to sustain normal lake water levels and lake surface area as long as temperature and wind speed, which enhance evaporation, continue increasing. This has implications for lake productivity processes and needs to be understood and incorporated in management of fisheries and the catchment areas as climate warming intensifies.
Effect of four wetland plants on nutrient removal and growth of eutrophic algae
Authors: Zhong Tao , Tian Yun-Hui , Song Ben-Ru , Chen Zong-Jing , Zhang Yang , Chen Zhang-He
Published: October 2017

We studied the removal of chlorophyll-a and eutrophic alga Ankistrodesmus acicularis by mixed and monoculture constructed wetlands of four common wetland macrophytes, Echinodorus berteroi, Hydrocotyle sibthorpioides, Vallisneria natans and Hydrilla verticillata. We also tested the effects of the macrophyte culture solution on the growth of three common eutrophic algae: Chlorella pyrenoidosa, Scnedesmus obliquus and Anabaena flosaquae.

The wetlands had significant effect on the removal of chlorophyll-a and A. acicularis. ANOVA results indicated a significant difference existed among different wetlands (P < 0.01). There was generally no significant difference between the mixed and the monoculture wetlands, while the mixed wetlands generally showed significant difference between them.

Results also indicated that there were significant differences in the effect on the growth of three algae among the culture solutions of different wetlands (p < 0.01). Almost all mixed culture solutions had a significant difference from their monocultures. Similarly, the monoculture treatments generally showed significant differences from their corresponding mixed treatments. However, combinations of different macrophytes generally cannot increase the effect intensity. The results indicated that combinations of macrophytes can produce different effects on alga growth from their monocultures and from their combinations with other macrophytes. Different algae showed different levels of susceptibility to the plant culture solution, and a same culture solution had different effects on different algae, including inhibiting, promoting, or neutral effects.
Contaminant concentrations and biomarkers in 21-day old Herring Gulls (Larus argentatus) and Double-crested Cormorants (Phalacrocorax auritus) from eastern Lake Ontario, and from Hamilton Harbour in western Lake Ontario in 1989 and 1990
Authors: Bishop Christine A. , Trudeau Suzanne , Janz David , Hughes Kimberley D.
Published: October 2017

This study measured concentrations of polychlorinated biphenyls, polycyclic aromatic hydrocarbons, organochlorine pesticides, trace metals and biochemical markers of contaminant exposure and potential toxicity (plasma and hepatic retinol, hepatic retinyl palmitate, ethoxyresorufin O-deethylase, hepatic porphyrins) in 21 day-old Herring Gull (Larus argentatus) and Double-crested Cormorant (Phalacrocorax auritus) chicks. The chicks were collected from breeding colonies at Hamilton Harbour, an industrialized site in western Lake Ontario, and at Snake and Pigeon Islands in eastern Lake Ontario in 1989 and 1990. The polycyclic aromatic hydrocarbons, benzo[a]pyrene and naphthalene, were detected in bile and concentrations were higher in both species, but particularly in Cormorants, at Hamilton Harbour in comparison to eastern Lake Ontario. Ethoxyresorufin O-deethylase activity correlated positively with polyaromatic hydrocarbon exposure in Cormorants. At Hamilton Harbour, Cormorants had significantly greater liver to body weight ratios, increased hepatic ethoxyresorufin O-deethylase activities and elevated plasma retinol concentrations compared to those from eastern Lake Ontario. Liver concentrations of selected polychlorinated biphenyl congeners were generally low (<2 ug g−1 w.wt) in birds from both areas but Hamilton Harbour Herring Gulls had mean concentrations that were significantly higher than eastern Lake Ontario Gulls, while Cormorants had low and similar polychlorinated biphenyl concentrations between sites. Trace metal levels did not vary substantially between sites for either species.
Hamilton Harbour Remedial Action Plan process: Connecting science to management decisions
Authors: Hall John D. , O'Connor Kristin M.
Published: October 2017

Hamilton Harbour is located at the western end of Lake Ontario and was designated an Area of Concern in 1985. The Stakeholder process consistently followed by the Hamilton Harbour Remedial Action Plan since the mid-1980s has been identified as one of the best methods for integrating science, public input, and management. Using examples from this Remedial Action Plan, connections between science and remedial actions are examined along with the relationship of science to the public and political decision makers. A case study in wastewater decisions in Hamilton Harbour is offered as an example of how the planning and management process integrated and used science to define and refine remedial actions. Important lessons about community values, communication, and timing are highlighted.
Population trends of colonial waterbirds nesting in Hamilton Harbour in relation to changes in habitat and management
Authors: Zanchetta Carolyn V. , Moore David J. , Weseloh D. V. Chip , Quinn James S.
Published: October 2017

Since 1975, the diversity and abundance of colonial waterbirds breeding in Hamilton Harbour have increased, making it an important nesting site on the Great Lakes. An adaptive management approach has been employed to control hyper-abundant species and guide conservation efforts for vulnerable species, with the goal of maintaining a diverse waterbird community. Four species exhibited increasing or stable population trends (1975–2013): Double-crested Cormorants (Phalacrocorax auritus; from 0 to 4747 nests); Black-crowned Night-Herons (Nycticorax nycticorax; ranged from 6 to 259 nests); Herring Gulls (Larus argentatus; from 0 to 244 nests); and Caspian Terns (Hydroprogne caspia; from 0 to 496 nests). Cormorants are currently above (2,500 nests), while Caspian Terns (400–600 nests), Night-Herons (100–200 nests) and Herring Gulls (200–300 nests) are within population targets set out in the Hamilton Harbour Remedial Action Plan. Despite conservation efforts, Common Terns (Sterna hirundo) declined from a peak of 1,028 nests (1990) to 333 nests (2013), although currently within the population target (300–600 nests). Ring-billed Gulls (L. delawarensis), through long-term management and habitat restrictions, were reduced from a peak of 39,621 nests (1990) to 11,133 nests (2013), but still exceed the target (<10,000 nests). Changes in the amount of available habitat have affected waterbird distributions: the loss of 42 ha (peak in 1999) of former nesting areas to development has been partially offset by the creation or securement of 1.9 ha of dedicated breeding habitat. Continued management, assessed and refined annually, is required to maintain species diversity in the area. Current management techniques focus on preventing Ring-billed Gulls from nesting on private lands and dedicated Tern nesting habitat, excluding Cormorants from nesting at specific sites, and reducing inter-specific competition with Night-Herons and Herring Gulls. Recommendations and considerations regarding future management and conservation efforts to reach Remedial Action Plan targets in the harbor are outlined.
Trends in Hamilton Harbour suspended sediment quality
Authors: Burniston Debbie A. , Jia Julia , Charlton Murray N. , Thiessen Lina , McCarry Brian E. , Marvin Chris H.
Published: October 2017

Suspended sediment quality in Hamilton Harbour has been assessed as part of a long-term monitoring study (1987–2012). Sampling locations reflected a range of shoreline activities and sources of chemical contamination to the harbour. Temporal data showed a trend toward decreasing levels of contamination by polycyclic aromatic hydrocarbons and polychlorinated biphenyls over the period from the late 1980s to the early 1990s, with a subsequent leveling off over the next two decades. The highest concentrations of both contaminants were detected in areas impacted by industrial activities along the southern shoreline and Windermere Arm, and deep-water areas of the harbour where fine-grained sediments ultimately accumulate. Areas of the harbor discharging residential or rural parts of the watershed exhibited generally lower levels of contamination. In addition to the relatively higher contaminant levels, areas along the southern shoreline and Windermere Arm characterized by historical industrial activities and associated contaminated sediments exhibited chemical profiles indicating an impact on suspended sediment and bottom sediment quality throughout the harbour. Continued monitoring after scheduled remedial activities should provide an assessment of the overall efficacy of management actions to improve sediment quality in Hamilton Harbour.
Glider-observed anticyclonic eddy in northern South China Sea
Authors: Shu Yeqiang , Xiu Peng , Xue Huijie , Yao Jinglong , Yu Jiancheng
Published: October 2017

Using high-resolution in situ data from gliders, satellite data of sea level anomaly and geostrophic currents, we presented the detailed structure of an anticyclonic eddy during spring 2015 in the northern South China Sea. The impact depth of the anticyclonic eddy reached about 1000 m and had a maximum temperature anomaly of about 3°C at ∼120 m and maximum salinity anomaly of more than 0.3 psu in the mixed layer. The maximum geostrophic velocities perpendicular to the glider path were about 0.3 m s−1 at 100 m. The estimated radius was about 72 km and the translation velocity was about 5.2 cm s−1. The rotational speed of the eddy was estimated to be 0.35 m s−1. The high temperature and large salinity of the anticyclonic eddy indicated it did not originate from the South China Sea locally. The analysis of water mass indicated the character of the eddy water was similar to Kuroshio water, and the time evolution of the sea level anomaly and surface geostrophic velocity anomaly further validated that it originated from the Kuroshio intrusion as a loop current to the southwest of Taiwan.
Trophic structure of shrimp-trawl catches in the Pearl River estuary in winter, using stable isotope analyses
Authors: Ke Zhixin , Tan Yehui , Huang Liangmin , Zhao Chunyu , Liu Huajian
Published: October 2017

The Pearl River estuary is the second largest estuary in the South China Sea. The species composition and trophic structure of shrimp-trawl catches from this estuary were investigated using stable isotope analyses during the winter of 2012. Crabs dominated the catches, constituting 37% of the total biomass in the inner estuary and 45% in the outer estuary. The δ15N and δ13C values for particulate organic matter gradually changed from the inner to the outer estuary. δ15N of particulate organic matter was more enriched in the inner estuary, while δ13C was more enriched in the outer estuary. Higher δ15N values in the inner estuary suggested a stronger influence from anthropogenic eutrophication. The δ15N and δ13C values of shrimp-trawl catches showed the same trends as the particulate organic matter. Trophic structure and faunal composition of shrimp-trawl catches varied greatly between the inner and outer estuary areas. The trophic niches were clearly distinct among fishery groups in the outer estuary. Community-wide metrics of stable isotope values showed that there was greater diversity of food sources and more complex trophic interactions in the inner estuary, whereas trophic levels were more evenly distributed in the outer estuary.
Long-term variations in oxygen in sub-tropical coastal waters: Influence of sewage effluent
Authors: Yuan Xiangcheng , Huang Hui , Zhou Weihua , Yuan Tao , Li Xiubao , Gao Yongli , Liu Sheng
Published: October 2017

The increase in population in the Pearl River delta region has increased domestic sewage and industrial discharges, which influences biogeochemical (e.g. carbon dioxide release) and environmental (e.g. oxygen depletion) conditions. Dissolved oxygen and dissolved inorganic carbon concentrations along with salinity, temperature, pH, and chlorophyll a at the surface were collected during seven cruises at eight stations in different months in 2005–2006 to document the seasonal influence of anthropogenic inputs on dissolved oxygen in different areas of Hong Kong waters. Long-term data during 1997–2006 were used to assess air-sea exchange of dissolved oxygen. Near the Pearl River estuary, dissolved oxygen was undersaturated, while partial pressure carbon dioxide was oversaturated, which indicated that Pearl River estuary influenced waters were heterotrophic and represented net sources of carbon dioxide to the atmosphere. In Victoria Harbour, where there was greater sewage effluent influence, however, the degree of dissolved oxygen undersaturation was even more than the Pearl River estuary influenced waters throughout the year. In contrast, the eastern waters, where there was less influence of anthropogenic inputs, showed seasonal variability: undersaturation of dissolved oxygen (∼90%) in the dry season shifting to slight oversaturation (∼105%) in the wet season. The monthly average air-sea influx of oxygen decreased by ∼50 to 200 mmol m−2 d−1 in the wet season relative to that in the dry season in Victoria Harbour, which was coupled with an increase in chlorophyll a from the dry to wet season. These findings are important in understanding why the eutrophication impact from nutrient enrichments in Hong Kong waters is not as severe as one would expect, and also how sewage effluent influences biogeochemical processes of dissolved oxygen and carbon in coastal waters.
Assessment of eutrophication in a subtropical lagoon in the Gulf of California
Authors: Ruiz-Ruiz Thelma M. , Arreola-Lizárraga José A. , Morquecho Lourdes , Mendoza-Salgado Renato A. , Martínez-López Aída , Méndez-Rodríguez Lía C. , Enríquez-Flores Javier
Published: October 2017

Understanding the susceptibility of coastal ecosystems to nutrient loads from anthropogenic sources and the extent of eutrophication in subtropical and tropical estuaries is still a challenge. This study assessed eutrophication in Guaymas Bay, a subtropical lagoon that receives nutrient-rich urban wastewater discharges. Eutrophication was evaluated by means of the Assessment of Estuarine Trophic Status model. Our results showed that the trophic status of Guaymas Bay was “good.” It is important to consider that: (1) the dissolved oxygen and chlorophyll a levels observed are indicative of a healthy ecosystem, and (2) the key factors explaining this finding are the high susceptibility to eutrophication of the lagoon and the dominance of macroalgae species that respond to nutrient enrichment. This implies that the Overall Eutrophic Condition Index of the Assessment of Estuarine Trophic Status model is a valuable tool for use as an eutrophication indicator based on the abundance of primary producers (macroalgae and phytoplankton). One source of uncertainty in the application of the model to this semi-arid coastal lagoon deals with estimating its susceptibility to eutrophication. The model showed that the lagoon is a highly sensitive ecosystem; however, significant factors are in place, such as an adequate water exchange, that reduce its susceptibility to eutrophication. In conclusion, the trophic status observed at Guaymas Bay is acceptable; however, an environmental management plan is necessary to prevent any adverse effects of eutrophication.
Studies on ecology, fish diversity and fisheries of Ken–Betwa rivers (India): Proposed for inter-linking
Authors: Joshi K. D. , Alam Md. A. , Jha D. N. , Srivastava K. , Srivastava S. K. , Kumar V. , Sharma A. P.
Published: October 2017

The Ken and Betwa rivers traversing through Central India are the major tributaries of the river Yamuna. Both rivers originate above 550 m above sea level in the Vindhya region. An interlinking project proposed for the rivers envisages diversion of water from Ken basin to the Betwa. The river sediment is alkaline and dominated by sand (78–89%) in both rivers. Oxygen-rich alkaline water and moderate values of chemical parameters show the pollution free and productive nature of both the rivers. There was no statistically significant difference in water quality between the Ken and Betwa rivers, except for total alkalinity. The biotic parameters were observed in similar ranges and moderate condition. A total of 61 planktonic forms were recorded from the rivers out of which 55 were phytoplankton. For the first time, 89 fish species belonging to 10 orders, 26 families, and 62 genera have been recorded in the river Ken, while 81 species classified under 10 orders, 24 families, and 55 genera were found in the Betwa. Exotic fish species were also observed in the downstream stretches of both rivers. Out of the total fish species, 77 were common to both rivers, 12 were found only in the Ken River, and 4 species were restricted to the Betwa. Analysis of relative abundance showed dominance of Labeo boggut in the Ken and Osteobrama cotio in the Betwa River. On comparison of the Shannon–Wiener Diversity and Evenness Indices of fish diversity, these indicated slightly higher values in the Ken (3.76 and 0.842) than the Betwa (3.66 and 0.835). A total of nine near-threatened fish species was recorded in the rivers. Both rivers have already been obstructed by many developmental projects; the proposed interlinking would further negatively impact the ecology and fisheries.
Elevated zooplankton production in a eutrophic Lake Ontario embayment: Hamilton Harbour 2002–2014
Authors: Bowen K. L. , Currie W. J. S.
Published: October 2017

Hamilton Harbour is an Area of Concern in western Lake Ontario, long stressed by cultural eutrophication, urbanization and invasive species. Despite high nutrient levels leading to hypolimnetic hypoxia and contaminated sediment, it is a highly productive environment. To better understand zooplankton dynamics in Hamilton Harbour, we conducted biweekly May to October sampling of zooplankton and rotifer composition at open water harbour sites from 2002–2014. May to October zooplankton density, dry biomass and total production averaged 265 ± 16 animals l−1, 306 ± 19 mg m−3 and 4131 ± 359 mg m−3, (±SE), respectively. These values are among the highest reported in the Great Lakes, with biomass two to seven times greater than in other eutrophic embayments. Zooplankton populations and taxonomic seasonality have remained relatively stable in Hamilton Harbour since 2002. Biomass is often dominated by smaller taxa such as Bosmina, Eubosmina and juvenile copepods, suggestive of high fish planktivory, but Daphnia retrocurva and D. galeata mendotae are also dominant during the summer, indicating improvements in the zooplankton community since the 1970s when Daphnia and cyclopoids were uncommon. Conversely, rotifers have declined over the last 40 years, though while still numerically dominant, now comprise <4% of total biomass and production compared to 40% in the 1970s. Both adult Dreissenid Mussels and their veliger larvae are less abundant in Hamilton Harbour compared to nearshore Lake Ontario. Zooplankton appear to be effectively utilizing high production rates of edible algae and microorganisms in the harbour. More work is needed to explore trophic interactions in this eutrophic ecosystem and the effects of hypolimnetic hypoxia on the zooplankton community.