bluuebunny/crossref_metadata_2025 huggingface dataset:
Interplay between Alfvén and magnetosonic waves in compressible magnetohydrodynamics turbulence
Authors: Andrés N. , Clark di Leoni P. , Mininni P. D. , Dmitruk P. , Sahraoui F. , Matthaeus W. H.
Published: October 2017

Using spatio-temporal spectra, we show direct evidence of excitation of magnetosonic and Alfvén waves in three-dimensional compressible magnetohydrodynamic turbulence at small Mach numbers. For the plasma pressure dominated regime, or the high β regime (with β the ratio between fluid and magnetic pressure), and for the magnetic pressure dominated regime, or the low β regime, we study magnetic field fluctuations parallel and perpendicular to a guide magnetic field B0. In the low β case, we find excitation of compressible and incompressible fluctuations, with a transfer of energy towards Alfvénic modes and to a lesser extent towards magnetosonic modes. In particular, we find signatures of the presence of fast magnetosonic waves in a scenario compatible with that of weak turbulence. In the high β case, fast and slow magnetosonic waves are present, with no clear trace of Alfvén waves, and a significant part of the energy is carried by two-dimensional turbulent eddies.
Electron heating and mode transition in dual frequency atmospheric pressure argon dielectric barrier discharge
Authors: Zhang Z. L. , Lim J. W. M. , Nie Q. Y. , Zhang X. N. , Jiang B. H.
Published: October 2017

Plasma ionization, excitation, mode transitions and associated electron heating mechanisms in atmospheric pressure dielectric barrier discharges (DBD) driven by dual radio frequency sources are investigated in this paper. The electrons are found to be heated mainly by the high frequency component in the plasma bulk when discharged in α mode. On the contrary, the low frequency component is primarily responsible for heating in the sheath which is caused by intense motion in the sheath. It was also found that variation of the lower frequency component ratio could effectively modulate the electron energy distribution as determined from time averaged EEDF. The results above have demonstrated that the independent control of plasma parameters via non-linear synergistic effect between the dual frequency sources can be achieved through reasonable selection of processing parameters.
Solvation structure and dynamics of Ag+ in aqueous ammonia solutions: A molecular simulation study
Authors: Sansotta Stefano , Zahn Dirk
Published: October 2017

We present an ab initio-based force-field for silver ion interactions with water and ammonia. Compared to quantum calculations, our model allows for rather large-scale molecular dynamics simulations of silver solutions of aqueous ammonia. For a series of NH3:H2O ratios ranging from 1 to 20 mol. %, Ag+ ions were mainly found as octahedral [Ag(NH3)x(H2O)]6−x+ coordination complexes with preferential values of x ranging from 0 to 3. In the first coordination structure, water ↔ ammonia exchanges occur within a 1-3 ps time scale and, depending on the NH3 concentration, imply significant fluctuations of x covering the whole range from 0 to 6. Based on ns-scale molecular dynamics simulations, chemical potentials are derived for all Ag+ coordination species as functions of temperature and ammonia concentration. Moreover, we compare the diffusion constants of the [Ag(H2O)6]+ to [Ag(H2O)3(NH3)3]+ coordination complexes, based on the solutions of the corresponding ammonia content.
Bacterial natural product biosynthetic domain composition in soil correlates with changes in latitude on a continent-wide scale
Authors: Lemetre Christophe , Maniko Jeffrey , Charlop-Powers Zachary , Sparrow Ben , Lowe Andrew J. , Brady Sean F.
Published: October 2017

Significance

Secondary metabolites encoded by soil bacteria have proved to be a rich source of lead structures for the development of small-molecule therapeutics. Environmental factors that contribute to differences in the composition of natural product biosynthetic gene clusters found in geographically distant soil microbiomes have remained elusive. In this study, we sought to address this key outstanding question. Of the factors we assessed, changes in latitude were found to correlate most consistently with changes in biosynthetic domain composition on a continent-wide scale. Although further studies are needed to better understand the underlying causes driving this relationship, these findings provide insights into how best to direct future natural product drug discovery efforts.
“Being Able to Speak”: What Individuals in Jail Perceived as Helpful about Participating in Alcohol-Related Brief Interventions
Authors: Owens Mandy D. , Kirouac Megan , Hagler Kylee , Rowell Lauren N. , Williams Emily C.
Published: October 2017

Background: A significant proportion of individuals within the criminal justice system meet criteria for a substance use disorder. Treatments for individuals who are incarcerated with substance use disorders show minimal to no benefit on postrelease outcomes, suggesting a need to improve their effectiveness, particularly those that can be delivered in a brief format. The purpose of this study was to describe what individuals in jail with substance use disorders perceived as being helpful about 2 brief alcohol-focused interventions, which can be used to inform future treatments with this population. Methods: Data came from a parent study where 58 individuals in jail with substance use disorders received either a motivational or educational intervention focused on alcohol and other substance use and then completed a questionnaire assessing what was most and least helpful about the interventions. Qualitative responses were coded using a grounded theory approach. Results: Results indicated that participants from both interventions reported that receiving individualized attention and talking one-on-one with someone was helpful, and that the interventions were encouraging and elicited hope. There also were specific components from each intervention that participants said were beneficial, including the opportunity to discuss plans for postrelease and to learn about addiction from psychoeducational videos. Participants noted areas for improving future interventions. Suggestions from participants were to offer tangible resources upon release, make session lengths flexible, and reduce assessment burden during research interviews. Conclusions: Findings align with established approaches for working with marginalized groups, namely, community-based participatory research methods and shared decision-making models for treatment. This study provided a voice to individuals in jail with substance use disorders, a group often underrepresented in the literature, and may offer an initial look at how to improve treatments for this high-risk population.
Estimation of suspended particulate matter in Gulf using MODIS data
Authors: Uddin S. , Al-Ghadban A. N. , Gevao B. , Al-Shamroukh D. , Al-Khabbaz A.
Published: October 2017

Mapping of suspended particulate matter can be achieved through satellite-based optical sensors and has growing applications for understanding sediment transport. A suspended particulate matter algorithm developed by Nechad (2010) for turbid conditions in the North Sea was applied in Gulf water using MODIS band 13 data centered at 667 nm. Satellite estimates of suspended particulate matter are extremely well correlated with the in-situ measurements (p = 0.97 and 1.00 for north (turbid) and south (clear) transects. Therefore, this technique can be effective for such estimation in Gulf waters as a surrogate for in-situ measurements.
Effect of different types of El Niño on primary productivity in the South China Sea
Authors: Liao Xiaomei , Ma Jinfeng , Zhan Haigang
Published: October 2017

More than ten years of satellite-derived net primary production (NPP) data were used to investigate the interannual variations of NPP associated with two different types of El Niño in the South China Sea (SCS). Results of the empirical orthogonal function analysis (EOF) showed that the first two modes had significant interannual variations and were sensitive to two types of El Niño. The first mode is highly correlated to the canonical El Niño. This mode is characterized by basin-scale decreased NPP during the canonical El Niño years, predominantly diminished off the east coast of Vietnam and the northwest coast of Luzon. The second mode is well correlated to the El Niño Modoki, showing increased NPP in the central and eastern SCS during the El Niño Modoki years. The interannual NPP variability is linked to anomalous atmospheric and oceanic conditions associated with these two types of El Niño. During the developing phase of El Niño Modoki, enhanced western North Pacific summer monsoon and moderate northeasterly wind divergence gave rise to the positive wind stress curl anomalies in the central and eastern SCS, inducing strong Ekman upwelling and increased upward nutrient supply. The moderate Ekman upwelling in the mature phase of El Niño Modoki also sustained the ocean primary productivity. Basin-scale decreased NPP in the SCS was attributed to anomalous weakened wind and abnormal warm sea surface temperature throughout the period of canonical El Niño.
A report on a Moon Jellyfish Aurelia aurita bloom in Sishili Bay, Northern Yellow Sea of China in 2009
Authors: Dong Zhijun , Liu Dongyan , Wang Yujue , Di Baoping , Song Xiukai , Shi Yajun
Published: October 2017

In recent years, an increasing number of reports on blooms of Moon Jellyfish (Aurelia aurita) have occurred in the northern coast of China. Throughout the summer of 2009, we studied the occurrence of an A. aurita bloom in relation to environmental variables in the Yantai Sishili Bay of the Northern Yellow Sea. The mean abundance of A. aurita was 0.62 no m−3 in summer 2009 with a highest density of 2.28 n m−3, while the mean biomass of A. aurita was 163.7 mg C m−3. Highest biomass peaked at 673.6 mg C m−3. The present study showed that the spatial distribution of A. aurita seemed unrelated to the environmental variables: sea surface temperature, salinity, dissolved oxygen and nutrients. Chlorophyll a concentration was positively correlated to the occurrence of A. aurita in summer 2009, suggesting a cascading effect resulting from the jellyfish grazing on zooplankton that in turn reduced grazing of zooplankton on phytoplankton. Increased suitable settlement and reduced currents in the Bay by intense building of coastal construction and aquaculture rafts were discussed as possibly being the main drivers for the proliferation of Moon Jellyfish A. aurita. Further investigations on A. aurita polyps in situ should be conducted to address this hypothesis and relate these to current management policies.
Population biology and stock status of planktonic shrimp Acetes indicus (Decapoda: Sergestidae) in the coastal waters of Malacca, Peninsular Malaysia
Authors: Amin S. M. N. , Arshad Aziz , Siraj Siti Shapor , Sidik B. Japar , Rahman M. Aminur
Published: October 2017

Reproductive cycle, growth, mortality and exploitation rate of Acetes indicus were examined in the coastal waters of Malacca, Malaysia between February 2005 and March 2007. Monthly length frequency data were analyzed using FiSAT software for estimating population parameters of A. indicus, including asymptotic length (L∝), growth co-efficient (K) and exploitation rate (E) to assess the status of the stock. The annual mean L∝ and K for males were estimated at 29.93 mm and 1.60 yr−1, and for the females were 40.95 mm and 1.20 yr−1. Mean growth performance index (φ′) was calculated as 3.15 and 3.31 for males and females, respectively. Maximum life span (tmax) of males and females was 1.88 and 2.50 years. Total mortality (Z) by length converted catch curve was estimated at 4.30 yr−1 for males and 3.62 yr−1 for females. The rate of natural mortality (M) for males and females was calculated as 2.54 yr−1 and 1.93 yr−1, and the fishing mortality (F) was 1.77 yr−1 for males and 1.70 yr−1 for females. Recruitment pattern of A. indicus was continuous throughout the year with two major peaks. The exploitation rate (E) of males was 0.41 and that of females was 0.47, though the exploitation rates were slightly less than the optimum level of exploitation (E = 0.50). Thus, the stock of A. indicus is under pressure in the coastal waters of Malacca, Malaysia.
Marine debris composition and abundance: A case study of selected beaches in Port Dickson, Malaysia
Authors: Khairunnisa A. K. , Fauziah S. H. , Agamuthu P.
Published: October 2017

Malaysia has a long coastline and is well known for its beautiful beaches which play different roles, depending on the characteristics and location. With increasing population and rapid development, the beaches are experiencing threats from pollution. One of the most visible threats is due to solid waste disposal. A scientific quantitative dataset of marine debris in Malaysia is, however, very rare. Therefore, a study on marine debris was conducted on two beaches in Port Dickson, Malaysia, from January to March 2010. The objective of the study was to compare the density of waste on two selected beaches with different economic activities.

Teluk Kemang and Pasir Panjang are recreational and fishing beaches, respectively. Pasir Panjang received at least 2 units of debris for every 2 m2 (0.495 ± 0.108 items m−2), weighing 46.079 ± 12.507 g m−2. Debris found in Teluk Kemang was lower than that of Pasir Panjang with 1 unit of waste for every 2 m2 (0.262 ± 0.045 items m−2), weighing 2.067 ± 1.238 g m−2. Based on the number of items, plastics were the most abundant type of debris at 64% in Teluk Kemang and 46% in Pasir Panjang. In terms of weight, paper was higher (48%) than plastic (43%) in Teluk Kemang, while the highest percentage of debris found on Pasir Panjang beach was bulky waste (54%). The number of items and weight of debris were higher in Pasir Panjang due to the abundance of huge and heavy abandoned nets from fishing activities left on the beach. Daily clean-ups of Teluk Kemang, a popular recreational beach, contributed to significantly lower amounts of debris found there. On the whole, types of waste found on both beaches were similar. However, the percentage and amount of each waste's type varied between the two beaches. The results indicated that the density of waste is highly dependable on the economic activities of the relevant beaches.
Microbial remediation of pollution in tropical coastal environments
Authors: Moriarty D. J. W. , Decamp O.
Published: October 2017

The impact of waste on the coastal environment from urban sources and the agriculture, manufacturing and aquaculture industries can be mitigated by the use of appropriate microbes either individually or in consortia with plants. Aquaculture—coastal land-based and estuarine or bay cage aquaculture—and urban sewage and industrial organic wastes are particularly amenable to microbial technologies. Several criteria must be applied to ensure success. Appropriate species for microbial technology, i.e. microbes that are natural to, or integrate easily into, the natural ecological communities and provide the desired beneficial actions, have to be selected and produced at a cost that is acceptable to the end users. The microbes have to be added at a high enough population density to compete with the natural flora in the treatment sites. Bacteria that carry genes for antibiotic resistance and disease virulence must not be used in sites where they could affect not only human, but also fish and shrimp health; safety checks must be made during selection and production processes. Microbial technologies are now being used widely in the field of aquaculture, where an obvious cost-benefit is seen at harvest. Microbial technologies can lower energy and other costs of treating of urban and industrial wastes and assist in meeting regulatory targets for effluent quality.
Resolving a persistent offshore surface temperature maximum in Lake Superior using an autonomous underwater glider
Authors: Austin Jay
Published: October 2017

In November 2009, an autonomous underwater glider (AUG) was deployed for a period of 12 days on the Wisconsin Shelf of Lake Superior. During this period, the AUG made repeated cross-shelf transects from 3 km to 13 km offshore, making 26 cross-shelf transects in all, during which time temperature was measured. Each of these transects displayed a mid-shelf temperature maximum roughly 8 km offshore, with cooler waters both inshore and offshore of this. This is hypothesized to be due to a balance of persistent cooling at the surface and vertical mixing of cooler sub-thermocline waters offshore.
Length weight relationships and fecundity estimates of long-spined Sea Urchin, Diadema setosum, from the Pulau Pangkor, Peninsular Malaysia
Authors: Rahman M. A. , Amin S. M. N. , Yusoff F. Md. , Arshad A. , Kuppan P. , Nor Shamsudin M.
Published: October 2017

The present study is an attempt to describe the size frequency distribution, length weight relationships and fecundity estimates of long-spined Sea Urchin, Diadema setosum from the Pulau Pangkor, Peninsular Malaysia. In total 101 specimens of D. setosum were collected from the inter-tidal reef of Pulau Pangkor of Parek during the breeding season in May–August, 2010. Individual total length (TL) was measured using digital slide calipers and individual body weight (BW) was taken using a digital balance. Mean length of D. setosum was estimated as 59.66 mm and the mean weight was 101.68 g. Among the 101 specimens, 52 were males and 49 were females, indicating a sex ratio of male to female of 1:0.94. The logarithmic form of length-weight relationship of D. setosum was Log W = −1.3977 + 1.9049*Log TL, while the exponential form of equation obtained for the length-weight relation was W = 0.04*TL1.9049. The value of regression co-efficient (r2) estimated for the species was 0.63. The mean fecundity was estimated at 7,313,600 (±567,992) with a range between 6,290,000 and 7,980,000 eggs. Analysis of the relationship between the absolute fecundity (F) and total length (TL), and also between the fecundity and drained body weight (DW), revealed a linear regression model with a positive and significant relationship. This study presents results on the total length-body weight relationships and fecundity estimates of this Sea Urchin from Pulau Pangkor, Peninsular Malaysia for the first time.
The achievement of water management objectives based on willingness to pay for a water service fee in tidal lowlands
Authors: Yazid Muhammad , Shamsudin Mad Nasir , Rahim Khalid Abdul , Radam Alias , Muda Azizi
Published: October 2017

The objective of this study was to estimate willingness to pay for a water service fee (WSF) in order to assess the expected achievement of water management objectives in tidal lowlands. A survey was conducted in Telang, a tidal lowland area on the eastern coast of Sumatra, involving 500 water users randomly drawn from approximately 60,000 people living in the delta. Each respondent was interviewed to obtain information regarding socioeconomic status and the willingness to pay for WSF. The data were analyzed using multiple regresion to obtain the estimate of WSF and its affecting factors. Results indicated that the mean WSF was $11.40 US. With this WSF, only the improvement of water distribution objectives could expect to be achieved.

Willingness to pay for WSF was significantly affected by the income of water users. Therefore, efforts to increase this willingness in order to achieve cost recovery and efficient water allocation should be directed towards the increase of income of water users.
Freshwater estimates of prokaryotic respiration in tropical Central America
Authors: Pollard Peter C.
Published: October 2017

In aquatic fresh ecosystems, prokaryotes are responsible for the bulk of aerobic respiration. They generate most of the CO2 from freshwater, yet rarely are their rates of respiration estimated in situ. Here, direct measurements were made of the rate at which freshwater bacteria and Archaea used dissolved oxygen in the tropical waters of the Panama Canal, Central America. Respiration rates were estimated from measurements of oxygen uptake rates in a dark chamber attached to a sonde in situ in bays, coves and the Panama Canal around Barro Colorado Island. The rate at which oxygen was taken up was then converted to the rate at which carbon dioxide was respired; rates ranged from 1 to 20 g C m−3 d−1. Results showed aquatic bacterial respiration in these tropical freshwaters can return large amounts of dissolved organic carbon to the atmosphere as CO2. Hence, CO2 outgassing from these tropical freshwaters respiration should be considered as a significant source of carbon to the atmospheric global carbon budget.
Predictive model for phosphorus in large shallow Lake Peipsi: Approach based on covariance structures
Authors: Haldna Marina , Möls Tõnu , Buhvestova Olga , Kangur Külli
Published: October 2017

Long-term datasets of nutrient levels provide a unique opportunity to study the changes that occur in lake ecosystems subjected to multiple man-induced and natural pressures. Unfortunately, the relevant dataset of thousands of records for Lake Peipsi (Estonia/Russia) is rather fragmentary and therefore difficult to analyse. Focusing on the total phosphorus concentration (TP), which is believed to be the main reason for degradation of the shallow lowland lake, we tailored, using SAS/STAT software, a special mixed regression model having 61 linear parameters and a repeated measures approach with spatial covariance structure. The model describes the dependence of TP in the surface water on year number (1985–2010), on the day of year and on geographical coordinates. Based on Akaike's criterion, the present model is superior to the analogous model, where the prediction errors (residuals) are supposed to be independent. Another advantage of the present model is that it distinguishes two groups of factors related to the variation in TP residuals. Factors of the first group affect TP synchronously within the larger areas, while this synchrony is weakening down to about 75 km or even more as has been shown by the SAS VARIOGRAM procedure. Factors in the other group can be associated with sampling instability and random errors in laboratory analyses. The influence of both factor groups on TP is approximately equal, with the related variance components on a log2-scale being 0.12 and 0.15.
Fish diversity, community structure and ecological integrity of the tropical River Ganges, India
Authors: Das M. K. , Sharma A. P. , Vass K. K. , Tyagi R. K. , Suresh V. R. , Naskar M. , Akolkar A. B.
Published: October 2017

The Ganges River is one of the largest river systems in the world and sustains a rich biodiversity of fish and fishers. In recent years, a decline in fish diversity and catch has become apparent due to various anthropogenic activities in the river basin. This study analyses the current fish diversity, distribution and community structure along the longitudinal gradient of the river and evaluates the ecological integrity of the riverine stretch applying a multimetric assessment approach. One hundred forty three fish species were recorded from the river and Cyprinidae was the dominant family. The middle stretch of the river exhibited dominance of small bodied erytopic, indigenous and exotic fish species with periodic and opportunistic life history strategies with significant decline of the large bodied prized Indian major carps. A tropic shift towards dominance of carnivore catfish species is evident. Non-metric multidimensional scaling revealed greater distribution and abundance of fish species with increasing river width and depth, higher sediment organic carbon, silt and clay along the river gradient. A significant change in the catches composition was evident from 1961 to 2010 in the middle stretch of the river at Allahabad. It reflected a progressive decline in proportion of Indian major carps (IMC) and the anadromous Shad Tenualosa ilisha and a significant increase in the proportion of exotic fish Cyprinus carpio and Oreochromis niloticus which represented 43–48% of the total catch. Assessment of biotic integrity showed that 28% of sample locations in the river supported fish assemblages under acceptable conditions.
Assessment of the effects of plerocercoid larvae of Ligula intestinalis (Cestoda) on Engraulicypris sardella (Cyprinidae) from northern Lake Nyasa/Malawi/Niasa
Authors: Msafiri A. , Kwendwa K. , Nestory P. G. , Alistidia M.
Published: October 2017

Engraulicypris sardella (Günter, 1868) is a cyprinid fish exploited in the waters of Lake Nyasa that has been found to be infested by Ligula intestinalis (Linnaeus, 1758). Although L. intestinalis has been the subject of a number of studies, there is no information on the effects of this parasite on E. sardella. This study was therefore aimed at assessing the prevalence and intensity of the parasite L. intestinalis, condition of the fish and impact on fecundity of E. sardella. Data recorded for each individual fish included: total length, weight, sex and maturity stage, number of parasites, gonad assessment and egg count. Number, length and total weight of  L. intestinalis found per fish host were recorded.

The average infestation rate from the two landing sites (Matema and Kafyofyo) was 32.5%. Kafyofyo had the highest infestation rate (50%) and Matema (15%); on average, each infested fish had 1.7 parasites. The majority of infested fish carried one parasite (57%) with 23.1% having two parasites, 13.8% three parasites, 1.5% four parasites and 4.6% five parasites. There was significant difference between the weight of fish with parasites and those without parasites (P < 0.05). Mean length and weight of parasites was 73.6 mm and 0.25 g, respectively. There was also a significant difference between the weight of gonads of infested and non-infested fish (P < 0.05). The average weight of gonads from infested fish was 0.28 g, while that of non-infected fish was 0.32 g. Gonads of all infected fish were atrophied. Number of eggs (fecundity) decreased significantly with parasite infestation. Condition factors of both infected and uninfected fish did not show any significant difference (Mann-Whitney U-test P > 0.01). Therefore, it was concluded that L. intestinalis parasites affect fecundity and consequently inhibit the reproductive capacity of this cyprinid fish population.
Diel vertical distribution and life history characteristics ofTropodiaptomus simplexand its importance in the diet ofStolothrissa tanganicae, Kigoma, Tanzania
Authors: Mgana H. F. , Herzig A. , Mgaya Y. D.
Published: October 2017

Tropocyclops simplex abundance, diel distribution and the impact of the planktivore fish Stolothrissa tanganicae on the T. simplex population were studied at a deep-water site in Kigoma Bay, Lake Tanganyika during the wet period (October 2008–February 2009). The top 40 m were examined using discrete depth samples, filtered through a 40-μm mesh. Ovigerous and copepodids of  Tropodiaptomus simplex exhibited a very clear diel vertical migration. Ovigerous females of Tropodiaptomus were negligibly low in the 0–30 m depth during the day, while at night they stayed above 20 m. Tropodiaptomus nauplii did not show any clear diel vertical migration. The contribution of adults, copepodite and nauplii stages to the total numbers of Tropodiaptomus simplex was 8.2, 8.6 and 83.2%, respectively. Stolothrissa tanganicae stomachs were analysed to quantify the contribution of zooplankton in their diets, which revealed a dominance of  Tropodiaptomus females and the electivity indices proved that T. simplex females (with or without eggs) were highly selected by S. tanganicae, which could probably be explained by size-selective feeding. Life table analysis indicated that approximately 60% of  T. simplex nauplii did not develop into copepodites, a loss which could not be explained by the results of the present study. 68% of the fish gut contents were contributed by female Tropodiaptomus individuals and the contribution of shrimps and Cyclopidae increased substantially to almost 20%. S. tanganicae consumed largely ovigerous Tropodiaptomus females. However, eggs found in the guts were significantly smaller than those found in the zooplankton discrete samples, suggesting that digestion had started. The calculated electivity indices underline that ovigerous and non ovigerous females of  T. simplex are being positively selected in the feeding process. It infers existence of selective predation in L. Tanganyika by S. tanganicae on females of  T. simplex (with or without eggs) and as a result distinct vertical migration as a predation escape mechanism is performed.
Feeding ecology of the intensively fished Nile Perch, Lates niloticus, in Lake Victoria, Uganda
Authors: Nkalubo Winnie , Chapman Lauren , Muyodi Fredrick
Published: October 2017

The diet of Nile Perch (8.0–121.0 cm total length [TL]) from the Ugandan waters of Lake Victoria was quantified through stomach content analysis of specimens collected from experimental catches and fish factory samples. A total of 7824 stomachs (5602 from experimental fishing and 2222 from factory samples) were examined, of which 34.8% contained food. Fish from the experimental catches were smaller (8.0–41.6 cm TL) and had a higher diversity of prey dominated by unidentifiable fish prey, haplochromine cichlids, Rastrineobola argentea, Odonata and Caridina nilotica, while larger fish (30.0–121.0 cm TL) from the factory samples had a predominance of fish remains and haplochromine cichlids. Nile Perch that had a high proportion of fish prey (versus invertebrates) in their stomachs showed a larger size for a given age, and were in a better condition (K = 1.24) than those that had primarily invertebrates (K = 1.10) in their stomachs. Nile Perch exhibited a much smaller size (15 cm versus 30 cm TL) at shift to piscivory in comparison to Nile Perch examined in earlier studies, when haplochromines were rare in Lake Victoria. The recovery of haplochromine cichlids coincident with declining Nile Perch densities illustrates the importance of developing sustainable management options that can define a proper balance between fishing mortality and Nile Perch predation.
Lake Tanganyika fisheries frame survey analysis: Assessment of the options for management of the fisheries of Lake Tanganyika
Authors: Van der Knaap M. , Katonda K. I. , De Graaf G. J.
Published: October 2017

From 1999 to 2011 some regions in the Lake Tanganyika Basin experienced humanitarian crises that displaced hundreds of thousands of people to neighboring countries. When relative calm returned to the region in 2008, an influx of displaced peoples and refugees returned to the lake seeking their ancestral fishing grounds. Well-meaning non-governmental organizations and United Nations-organizations donated fishing equipment to these returning people to aid their livelihood opportunities. These fishing programs, however, increased uncontrolled fishing effort on Lake Tanganyika beyond that of previous levels, resulting in decreasing fish catches. Increased monitoring of the fishery, therefore, became essential.

In 2009, as a result of uncontrolled fishing effort due to the influx of returnees, inefficient national efforts to monitor their fisheries, and the observed decline of fishery resources, the four countries bordering Lake Tanganyika (Burundi, Democratic Republic of Congo, Tanzania and Zambia) established a regional coordinating body called the Lake Tanganyika Authority to implement fisheries conservation and management measures in compliance with the Convention on the Sustainable Management of Lake Tanganyika. To inform and enable a fisheries monitoring program on Lake Tanganyika, the Authority conducted a lake-wide fisheries frame survey in 2011 to inventory the number of fishermen, fishing units and fisheries infrastructure around Lake Tanganyika.

When comparing the 2011 frame survey with data from a similar survey conducted in 1995 (the two most extensive studies to date on Lake Tanganyika), results revealed troubling trends in fish capacity, including: an increase in illegal fishing gear, a doubling of the total number of fishermen and fishing units, and a decline in catch rates since 2002 (based on Burundi data which has been consistently collected).

This article analyzes the trends of the Lake Tanganyika fishery, including: fishing effort, the changing uses of gear, and trends in employment in the fishery. Because of the observed increase of fishing capacity (e.g. the numbers of vessels, licenses and fishermen), this article addresses whether an effective fishery management program can be implemented on the lake. Past management efforts have been made from within the basin by the individual countries (Burundi, Democratic Republic of Congo, Tanzania and Zambia), transnational organizations (Food and Agriculture Organization), and the Lake Tanganyika Authority. Using current notions of fishery management on large lakes in the region and ideas from a case study from Gambia, West Africa, this study suggests that effective fishery management on Lake Tanganyika requires the adoption of a formal Monitoring, Control & Surveillance system, community surveillance, an improvement in licensing systems, and a limitation in the number of fishermen and fishing units.
Fish species composition, distribution and abundance trends in the open-coastal waters of northeastern Lake Ontario, 1992–2012
Authors: Hoyle J. A.
Published: October 2017

Bottom set gill nets were used to describe and track the fish community in northeastern Lake Ontario from 1992–2012. Six fixed, depth-stratified transects, spread more or less evenly from the mouth of the St. Lawrence River in the Kingston Basin to Brighton in central Lake Ontario, were sampled annually during summer. The balanced sampling design provided a broad picture of the warm, cool and coldwater fish community inhabiting open-coastal waters out to about 30 m water depth. Catch results were summarized by geographic area and depth strata to describe species distribution patterns, and presented graphically to illustrate annual abundance trends of the most important fish species (Alewife, Lake Trout, Yellow Perch, Walleye, Round Goby, Lake Whitefish, Brown Trout, Rock Bass, Smallmouth Bass, Chinook Salmon, Burbot, Cisco and Round Whitefish). Many of these dominant species showed peak abundance levels in the early 1990 s followed by decline. Of particular note, members of the coldwater benthic-oriented species assemblage, having all declined dramatically in the 1990s, remain at very low abundance levels, and their future prognosis appears bleak.
Lake Ontario zooplankton in 2003 and 2008: Community changes and vertical redistribution
Authors: Rudstam L. G. , Holeck K. T. , Bowen K. L. , Watkins J. M. , Weidel B. C. , Luckey F. J.
Published: October 2017

Lake-wide zooplankton surveys are critical for documenting and understanding food web responses to ecosystem change. Surveys in 2003 and 2008 during the binational intensive field year in Lake Ontario found that offshore epilimnetic crustacean zooplankton declined by a factor of 12 (density) and factor of 5 (biomass) in the summer with smaller declines in the fall. These declines coincided with an increase in abundance of Bythotrephes and are likely the result of direct predation by, or behavioral responses to this invasive invertebrate predator. Whole water column zooplankton density also declined from 2003 to 2008 in the summer and fall (factor of 4), but biomass only declined in the fall (factor of 2). The decline in biomass was less than the decline in density because the average size of individual zooplankton increased. This was due to changes in the zooplankton community composition from a cyclopoid/bosminid dominated community in 2003 to a calanoid dominated community in 2008. The increase in calanoid copepods was primarily due to the larger species Limnocalanus macrurus and Leptodiaptomus sicilis. These cold water species were found in and below the thermocline associated with a deep chlorophyll layer. In 2008, most of the zooplankton biomass resided in or below the thermocline during the day. Increased importance of copepods in deeper, colder water may favor Cisco and Rainbow Smelt over Alewife because these species are better adapted to cold temperatures than Alewife.
Has climate variability driven the trends and dynamics in recruitment of pelagic fish species in Swedish Lakes Vänern and Vättern in recent decades?
Authors: Sandström Alfred , Ragnarsson-Stabo Henrik , Axenrot Thomas , Bergstrand Eva
Published: October 2017

We analyse trends and dynamics in time-series of recruitment in Smelt and Vendace in the Swedish large Lakes Vänern and Vättern, with particular emphasis on the importance of climate variability. Climate-related predictor variables in our analyses were air temperature, water temperature, ice coverage and duration of ice winters. The variation between years with successful recruitment and years with low recruitment was considerable in both species and especially for Vendace. Ultra-oligotrophic Lake Vättern was characterized by strong pulses in Vendace recruitment, occurring mainly in four year intervals. Smelt recruitment was positively related to recruitment pulses of Vendace. In meso-oligotrophic Lake Vänern, Vendace pursuit was more successful in years with long ice winters that lasted until the middle of March or longer. Smelt recruitment in Lake Vänern was positively correlated to the air temperature in April. There was no obvious synchrony in recruitment patterns between the two lakes. Recruitment of Smelt in Lake Vänern’s two main basins was, however, positively correlated. The results indicated that climate factors may influence the recruitment of important pelagic species, but that the effects may differ between lakes, even though the systems are adjacent and situated at the same latitude.
Diversity analysis of diazotrophs associated with corals from Xisha and Sanya, South China Sea
Authors: Yang Qingsong , Dong Junde , Zhang Yanying , Ling Juan , Wang Dongxiao , Wu Meilin , Jiang Yufeng , Zhang Yuanzhou
Published: October 2017

In recent years, many studies have shown an increase in coral associated microbial biodiversity in coral diseases. However, the variation of coral diazotroph, which plays an important role in the nitrogen cycle, is still unclear. To explore the changes of nitrogen fixing microbial communities, we analyzed the diversity of nitrogen-fixing bacteria associated with corals in healthy vs. diseased conditions, and corals from two different locations (Xisha and Sanya). The diversity of nitrogen-fixing bacteria associated with two coral species, Porites lutea and Pocillopora damicornis were assessed using cloning and sequencing of the nitrogenase gene nifH. Phylogenetic analysis indicated coral associated diazotrophs community structure varied in different coral species: Chlorobi dominated in Porites lutea, while Alphaproteobacteria and Gammaproteobacteria were the most abundant nitrogen-fixing bacteria in Pocillopora damicornis. The dominant group of nitrogen-fixing bacteria was Chlorobi in healthy Porites lutea, but Cyanobacteria predominated in diseased ones. Moreover, the dominant nitrogen-fixing bacteria Gammaproteobacteria was replaced by Alphaproteobacteria in coral Pocillopora damicornis, from open sea to the coast. The diseased and coastal corals contained higher diversity of nitrogen-fixing bacteria than the healthy and open ocean corals. In conclusion, the nitrogen-fixing bacteria community structure shifted in response to the variation of coral species, coral health status and surrounding environments.
The baseline of coral reef water quality in Xisha Islands waters of South China Sea under southwest monsoon
Authors: Dong Jun-De , Li Yuan-Chao , Wang You-Shao , Wang Dong-Xiao , Wu Mei-Lin
Published: October 2017

The Xisha Islands, located off Sanya, South China Sea, are a group of islands administered by Hainan Province of the People's Republic of China. Due to little human activity, they are well preserved. Such conditions suggest that changes in ecosystem are mostly related to natural behavior. A baseline of water quality was established in May and July, 2012. The results of multivariate analysis showed changes in nutrients as the most significant variable in describing water quality. Hydrologic heterogeneity showed little change, but temporal characteristics presented distinguishable variations. This information may be valuable for socioeconomic development and human health in Xisha island waters.
Prioritization of sites for sediment remedial action at Randle Reef, Hamilton Harbour
Authors: Milani D. , Grapentine L. C.
Published: October 2017

Hamilton Harbour, an enclosed embayment at the western end of Lake Ontario, was designated as an Area of Concern in 1985 under the Great Lakes Water Quality Initiative. The harbour has been disturbed by wastes from steel industries, municipal wastewater discharges, and urban runoff. The area of the harbour known as Randle Reef has the largest volume of polycyclic aromatic hydrocarbon contaminated sediment on the Great Lakes and will be undergoing a major remediation project. An engineered containment facility will be constructed on top of the most contaminated sediment and surrounding sediments will be dredged and placed inside the engineered containment facility, or capped. To determine where remediation was required, areas were prioritized according to toxicity and contaminant concentrations. Although benthic invertebrate community assessment can be the best indicator of in situ toxicity, this was problematic in the harbour due to lack of appropriate reference areas for comparison and potential effects of other stressors (e.g. disturbances of sediments from ship traffic, seasonal low hypolimnetic oxygen concentrations). Initial prioritization of areas for remediation was therefore based on toxicity to benthic invertebrates and the associated contaminant levels. In 2002, 80 sites were sampled and laboratory bioassays conducted with the Amphipod Hyalella azteca and the Mayfly Hexagenia spp. Initial site prioritizations were established based on: (1) high contamination and toxicity; (2) high contamination and no/low toxicity; (3) low contamination and toxicity; and (4) low contamination and no toxicity. Final prioritizations considered study design and area considerations as well as additional sediment data obtained to address data gaps. Of the 80 sites, 79% were classed in a priority subgroup, while remaining sites were deemed non-priority.
Dynamic of the upper cross-isobath's flow on the northern South China Sea in summer
Authors: Wang Qiang , Wang Yinxia , Zhou Weidong , Wang Dongxiao , Sui Dandan , Chen Ju
Published: October 2017

Based on simulation, the summer upper-ocean cross-isobath's flow on the Northern South China Sea has been analyzed. East to Xisha water, the cross-isobaths flow mainly onshore, including little offshore flows. On Xisha water, the sea water flows onshore on the north side and is reversed on the other side. The momentum balance shows that the along-isobath's barotropic pressure gradient determines the distribution of the cross-isobath flow. Theoretical analysis shows that the along-isobath's density gradient and the windstress curl are two important factors that determine the along-isobath's sea surface height gradient, which is the main contributor to the barotropic pressure gradient. Numerical experiments demonstrate that the temperature distribution dominates the along-isobath's density gradient and determines the along-isobath's sea surface height gradient.
Seasonal and spatial variations of macrobenthic community structure and diversity in the South Yellow Sea
Authors: Xu Yong , Li Xinzheng , Wang Hongfa , Zhang Baolin
Published: October 2017

Seasonal and spatial characteristics of the macrobenthic community in the South Yellow Sea were studied based on data from three voyages carried out in spring, summer and autumn, 2012. Twenty six stations were sampled and divided into three regions (west, middle and east region of South Yellow Sea). A total of 218 species were obtained with Polychaeta and Crustacea being the predominant groups. Mean abundance varied from 151.4 ind. m−2 in spring to 188 ind. m−2 in autumn showing an increasing trend with season, and mean biomass ranged from 12.1 g m−2 in spring to 33.4 g m−2 in summer. Mean secondary productivity varied from 0.21 g (AFDW)/(m2·month) in spring to 0.48 g (AFDW)/(m2·month) in summer. Biomass was significantly different among seasons, and number of species, secondary productivity and Shannon-Weiner index had significant differences among regions. Abundance, Pielou's evenness index and average taxonomic distinctness were not significantly different among seasons nor regions. Overall significant differences of community structure among both seasons and regions were detected. Depth and the distance from shore were important factors influencing the distribution of macrobenthos in South Yellow Sea.
Improvements in fish polychlorinated biphenyl and other contaminant levels in response to remedial actions in Hamilton Harbour, Ontario, Canada
Authors: Neff Margaret R. , Stefanoff Samantha , Bhavsar Satyendra P.
Published: October 2017

Hamilton Harbour, located in Ontario, Canada at the western end of Lake Ontario, is recognized as one of the most anthropogenically-impacted regions within the Great Lakes and is currently listed as an Area of Concern. One of the Beneficial Use Impairments for the harbour has been restrictions on fish consumption due to elevated contaminant levels. In this study, we examined past and recent fish contaminant data collected by the Ontario Ministry of the Environment and Climate Change in partnership with other agencies to evaluate temporal trends in fish contaminant concentrations. Measurements for both resident and migratory sport fish as well as juvenile/forage fish were considered, with analysis focused on polychlorinated biphenyls, the group of chemicals identified as the major contaminant of concern. Current contaminant levels were evaluated against fish consumption advisory benchmarks used by Ontario Ministry of the Environment and Climate Change, and compared with corresponding observations for other locations across the Great Lakes, including other Areas of Concern. The results show statistically significant improvements in fish contaminant levels within Hamilton Harbour, with recent fish mercury concentrations below the first advisory benchmarks for all species included in this study. Polychlorinated biphenyl concentrations declined by 59–82% from historical levels, although this decline was not statistically significant in Brown Trout, Common Carp, Freshwater Drum and White Sucker. Further, all species exhibit recent polychlorinated biphenyl concentrations above the first consumption advisory benchmark of 105 ng g−1. Compared to other Great Lakes locations, including other areas of concern, Hamilton Harbour polychlorinated biphenyl concentrations remain amongst the highest. The results suggest that recovery of Hamilton Harbour is still on-going.