Zooplankton ecology

Different approaches have been developed with the aim of mitigate the impact of jelly sh blooms in coastal areas. These include warning ags, specialized anti-jelly sh nets and, to a much lower extent, risk maps for jelly sh blooms. The Medjellyrisk Project (www.jellyrisk. eu) aimed to create a western and central Mediterranean Basin forecasting platform. An integrated Collaborative Citizen Science approach has combined abundance data on stranded individuals of jelly sh and those recorded in coastal waters from four different Mediterranean countries (Spain, Italy, Tunisia and Malta) in a single database. The aim of this work is to create a forecasting platform where the probability of a jelly sh bloom arising can be foreseen. Stranded and near-to-coast jelly sh presence data was processed using a Species Distribution Model (SDM) approach, where different correlative and classi cation models were tted on the abundance data so as to create an ensemble of predictions. Different water environmental variables were used as explanatory variables, depending of the spatial location and jelly sh species of concern. Those spatially-explicit predictions were then projected in time using data from the MyOcean program (). Jelly sh presence data as well as the forecasted probability of a jelly sh bloom arising was communicated to the general public through the free-download mobile App (iMedjelly) and from the project's webpage ( sh-presence-forecasting-selector), providing citizens with up-to-date and validated information. In this way, this project reacted to the large demand by different beach users, stakeholders and institutions for such management tools within bathing areas.

Science is addressing global societal challenges, and due to limitations in research financing, scientists are turning to the public at large to jointly tackle specific environmental issues. Citizens are therefore increasingly involved in monitoring programs, appointed as citizen scientists with potential to delivering key data at near to no cost to address environmental challenges, therein fostering scientific knowledge and advising policy- and decision-makers. One of the first and most successful examples of marine citizen science in the Mediterranean is represented by the integrative and collaborative implementation of several jellyfish-spotting campaigns in Italy, Spain, Malta, and Tunisia starting in 2009. Altogether, in terms of time coverage, geographic extent, and number of citizen records, these represent the most effective marine citizen science campaigns thus far implemented in the Mediterranean Sea. Here, we analyzed a collective database merging records over the above f...

Zooplankton community structure and body size are recognized as sensitive indicators of marine ecosystem responses to environmental variability and human-induced pressures. In this study, we used a two-decade dataset (2002-2022) collected from a coastal station in the Sea of Marmara to investigate long-term changes in zooplankton community components, dominance patterns, and body size dynamics. Copepoda and Cladocera remained the dominant components throughout the study period; however, a notable seasonal expansion of Cladocera dominance and a replacement of key copepod species were observed over time. Two distinct periods (P1: 2002-2009; P2: 2017-2022) were compared to identify structural and functional shifts. Body size declines were recorded in major taxa, particularly in Acartia clausi and Paracalanus parvus, coinciding with seasonal temperature anomalies and major ecological events. Generalized Additive Models were applied to assess the influence of temperature and chlorophyll-a concentration on species-specific dominance and body size variability. Results indicated significant relationships between environmental variables and zooplankton traits, with species showing distinct responses to thermal and productivity shifts. Our findings emphasize the importance of implementing such as body size and trophic role into future assessments of ecosystem resilience under changing environmental conditions.

Warming temperatures and declining oxygen are well-studied in eutrophic coastal systems. To help broaden understanding we investigate non-eutrophic Massachusetts Bay, a representative well-flushed temperate embayment with seasonal thermal stratification, minor river inputs, and residence time of about a month due to exchange with the Gulf of Maine. Long-term trends are computed from de-seasoned measurements over 31 years (1992-2022) at nine bay sites, each sampled at five depths from sea surface to seafloor six times annually. For averages across all stations and depths, the mean warming and oxygen decline rates are +0.0582 (95% C.I. +0.0410 to +0.0759) °C yr 1 and 0.750 (0.985 to 0.524) μmol kg 1 yr 1 [ 0.0246 (0.0323 to 0.0171) mg L 1 yr 1 ]. The observed warming reduces oxygen solubility, per seawater properties, at a rate about half the observed oxygen decline. Rates do not differ significantly by site, including near a seafloor outfall releasing treated wastewater effluent, nor at different depths. Because warming is comparable at all depths there is no significant trend in stratification. There is a significant trend of increasing salinity, similarly uniform across sites and depths. A strong hypothesis to explain the warming and salinity trends is advection of Gulf of Maine water into the bay, rather than local influences that could be expected to cause spatially differing rates contrary to those observed. Advection is also a plausible explanation for the observed oxygen decline beyond that due to the solubility decrease. This study highlights potential influence of external ocean forcing on long-term trends in a coastal waterbody. Plain Language Summary Global climate change effects include warming and decreasing oxygen of seawater. In many areas warming causes species shifts restructuring ecosystems, and oxygen is low enough to harm organisms, known as hypoxia. Attention has focused on the deep ocean and some coastal systems, particularly those experiencing hypoxia. This investigation examines Massachusetts Bay, a representative temperate coastal embayment well-flushed by water from outside its boundaries, where hypoxia has not occurred. The study uses a 31-year data set collected to monitor bay response to installation of an outfall releasing treated effluent from the Boston metropolitan area wastewater facility. We find external ocean forcing likely drives bay warming and salinity trends. Seawater at higher temperatures can hold less oxygen; through this effect, the observed warming accounts for more than half the observed oxygen decline. External ocean forcing is also a plausible hypothesis for the remainder of the oxygen decline. In contrast to coastal systems less affected by exchange with outside waters, local processes have weak influence, including the wastewater effluent. Seasonally occurring density stratification, or water layering with less-dense warmer layers overlying more-dense cooler layers, shows effectively no long-term change because warming is occurring similarly at all depths.

The ecology of Rotifera of the Shatt Al-Arab region was studied at five stations: Khalid Birdge (1), Basrah Silo (2), Tanoma Bridge (3), Khirtrad creek (4) and a pond near the College of Engineering (5). Monthly vertical hauls were taken by 50 µm plankton net from near the bottom to the water surface during February 2007 to March 2008. Density of zooplankton fluctuated between 1.36 and 836.31 ind./L. Maximum density was at station 5 and the minimum was at station 1. Rotifera dominated the zooplankton at all stations, ranging from 1.09 to 650.99 ind./L at stations 1 and 5 , respectively. Peak density of Rotifera was recorded at station 5 which is the highest value ever recorded from any aquatic habitat at Southern Iraqi wetlands. Ninety nine species of Rotifera belonging to 23 genera and 15 families were encountered. Synchaeta lakowitziana and Bdelloidea were the most dominant groups at all stations during the study period. The ecological indices measured were: richness (1.32-8.43), Shannon-Weaver diversity index (0.99-2.36), evenness (0.59-0.91) and similarity index. The highest value of diversity was recorded at station 5. The highest similarity index (35.54) was between stations 1 and 2, while the lowest value (20.66) was between stations 4 and 5. Positive correlations were found between density of Rotifera and water temperature, total solids, chlorophyll a and phytoplankton. Significant differences were occurred between most of the ecological factors at different stations. Associations between Rotifera assemblages and environmental variables were quantified by using Canonical Correspondence Analysis (CCA), indicating a correspondence of the correlation values with those calculated by usual methods.

Zooplankton communities have several vital functions within lake ecosystems including the transfer of energy and material from producers to secondary consumers. Its structure is potentially affected by both lake morphology and typology, as well as anthropogenic changes in lakes. These communities are also sensitive to various substances in the water column, including nutrient enrichment and pollutants. Thus, they have often been used as indicators to assess the condition and change of the freshwater environment. Our aim was to present first detailed data about the species composition of zooplankton communities in two understudied Bulgarian reservoirs, the Konush and Sinyata Reka. Samples were collected from several stations in spring and summer 2016. The qualitative analysis of the zooplankton revealed the presence of three main taxonomic groups: Rotifera, Cladocera and Copepoda. From these, rotifers were best represented as number of species and abundance, followed by cladocerans a...

Iraq faces a complex water crisis that is expected to persist and might have inferences at the humanitarian, economic, security and social levels. The main water resources in Iraq are represented by the surface water of both Tigris and Euphrates Rivers. This research focuses on understanding the variations in water quality within five stations on Tigris and Diyala Rivers, estimation of Water Quality Index (WQI) for agricultural uses for the period 2021-2023 taking in consideration significant water quality parameters. Furthermore, creating WQI mapping based Inverse Distance Weight (IDW) by using Geographic Information System (GIS) and investigating the pollutant sources. The significance of the study is to classify the water within the study area according to the suitability for irrigation since irrigation sector consumes the largest amount among other uses. This is in turn helps the decision makers in determining the appropriate solutions to mitigate the deterioration of water quality. Results show that the water quality in four out of five stations is suitable for irrigation (WQI > 80) whilst one station (Al-Krgholiea) is moderately suitable for irrigation (WQI ranges from 60 to 80).

One of the most useful water streams in Egypt is the Ismailia Canal. However, despite its significance, numerous factories discharge their waste into the canal, causing a drastic decrease in its water quality and fauna. In this respect, this study aims to evaluate the negative impact of fertilizer discharge on community structure, zooplankton biodiversity, and water quality in the Ismailia Canal. Four stations were selected, where the Canadian Water Quality Index and the Metal Index were used to determine the point source of contamination at each station. As revealed in the Canadian WQI results, Stations (3) and (4) have marginal water quality, but no metal pollution was shown in the Metal Index results of the study area. The Canonical Correspondence Analysis (CCA) was also applied. The zooplankton community structure and biodiversity were examined, where their total density recorded an average of 598,854 ind./m 3. Nineteen zooplankton species-belonging to the groups: Rotifera, Cladocera, Copepoda, and Nematoda-were identified. Rotifera was predominant, representing 97.05% of the total zooplankton density. Although Station (3) had the highest diversity index, there was a special abundance of organic matter bio-indicators. That is why mandatory laws and management plans had to be enforced to mitigate the canal deterioration.

Biodiversity of zooplankton in the Tigris River running in Baghdad City, central Iraq, was investigated. Fourteen physical and chemical parameters, were analyzed, these parameters include water and air temperature, pH, EC, turbidity, TDS, DO, BOD 5 , total hardness, Ca +2 , Mg +2 , chloride, nitrate and reactive phosphate. Most of these values were within of the Iraqi and international standard limits. In all, 106 taxonomy units of zooplankton were identified, including 65 taxa belonging to rotifers, 25 taxa to copepod and 16 taxa to Cladocera. Values of species richness index of rotifers varied from 1.051 to 12.98, for Cladocera from 1.285 to 3.41 and for copepod from 1.5 to 7.2. The Shannon-Weiner index of Rotifera varied from 0.67 to 3, 0.50-1.72 for Cladocera and from 0.91 to 2.51 for Copepoda. The uniformity index of zooplankton varied from 0.41 to 0.93 for rotifer, 0.33-1 for Cladocera and 0.36-1 for Copepoda. According to statistical analysis, temperature, EC, TDS and dissolved oxygen were observed as major factors which restrict the abundance and diversity of the zooplankton communities in the Tigris River.

Three Eurasian otters (Lutra lutra) originating from Pazardzhik Region (South Bulgaria) were examined for helminth parasites. Three species of acanthocephalans were recorded: Pomphorhynchus laevis, Acanthocephalus anguillae and A. ranae. These species are not specific parasites of otters, the former two occurring in various freshwater fishes and the latter being a parasite of anurans. A review of acanthocephalan species recorded from L. lutra is presented. The possible transmission routes by which otters become infested with acanthocephalans are considered to be either paratenic transfer of encysted extra-intestinal juveniles in paratenic hosts or postcyclic transmission of mature intestinal worms in definitive hosts.

The distribution of euphausiid larvae along the coast of Terre Adélie, Antarctica, was assessed using oblique tows of a double-framed bongo net at 38 stations during summer 2004. Larvae of Euphausia crystallorophias and Thysanoessa macrura were observed. For E. crystallorophias larvae, the calyptopis I stage was dominant along the coast, while the most commonly observed stage of T. macrura was the furcilia. The distribution of E. crystallorophias larvae were correlated with abiotic factors, including depth and sea surface salinity, whereas those of T. macrura larvae were correlated with biotic factors, especially chlorophyll a and nitrate. Developmental stages of both species increased in age from west to east in the survey area, with younger developmental stages (metanauplius and calyptopis I) in the western part of the region and older stages (calyptopis II and III and furcilia I to VI) in the eastern part near the Mertz Glacier Tongue (MGT). It is suggested that these patterns co...

Prey modify their behaviour to avoid predation, but dilemmas arise when predators vary in hunting style. Behaviours that successfully evade one predator sometimes facilitate exposure to another predator, forcing the prey to choose the lesser of two evils. In such cases, we need to quantify behavioural strategies in a mix of predators. We model optimal behaviour of Atlantic cod Gadus morhua larvae in a water column, and find the minimal vulnerability from three common predator groups with different hunting modes; 1) ambush predators that sit-and-wait for approaching fish larvae; 2) cruising invertebrates that eat larvae in their path; and 3) fish which are visually hunting predators. We use a state-dependent model to find optimal behaviours (vertical position and swimming speed over a diel light cycle) under any given exposure to the three distinct modes of predation. We then vary abundance of each predator and quantify direct and indirect effects of predation. The nature and strength of direct and indirect effects varied with predator type and abundance. Larvae escaped about half the mortality from fish by swimming deeper to avoid light, but their activity level and cumulative predation from ambush predators increased. When ambush invertebrates dominated, it was optimal to be less active but in more lit habitats, and predation from fish increased. Against cruising predators, there was no remedy. In all cases, the shift in behaviour allowed growth to remain almost the same, while total predation were cut by one third. In early life stages with high and size-dependent mortality rates, growth rate can be a poor measure of the importance of behavioural strategies.

Gorgona National Park protects fertile waters that support large vertebrates, including green sea turtles (Chelonia mydas), and for them, gelatinous zooplankton constitute a food resource that can be found year-round in Gorgona island´s coastal waters. This study was carried out to determine the abundance of salps and doliolids around Gorgona island over a year, and to determine whether this is a resource that could be used reliably year-round by green turtles and other large plankton-feeding predators. The monthly abundance of salps and doliolids at eight coastal stations around Gorgona island (Colombian Pacific) was determined between September 2005 and August 2006. Oblique tows were carried out from 50m to the surface, total zooplankton biomass was measured and the number of salps and doliolids per tow, and frequency of occurrence per station and month were determined. Superficial and bottom sea temperature, superficial and bottom salinity, and chlorophyll-a concentration were recorded at each station. There were tunicate abundance peaks in September 2005 and March 2006. The high abundances in March were probably due to a cold water intrusion into the study area, which resulted in colder saltier water and a shallower thermocline. Tunicates were probably advected to the area by currents from the southwest and aggregated due to the underwater topography. in September, the influence of continental river discharge as well as inputs from rainfall over the island could have provided increased nutrients and resulted in higher abundances. The large filter-feeding vertebrates that feed on tunicates include green sea turtle juveniles, which use coastal waters of Gorgona island as feeding grounds, as part of their migration route in the Eastern Tropical Pacific. These turtles could be using tunicates opportunistically, as a sporadic resource that is available at certain times of the year.

Long-term and seasonal dynamics of zooplankton abundance and taxonomic composition and its relationship with meteo-climatic and hydrographic factors were investigated on the northwest Iberian shelf. Zooplankton were collected monthly (1995 -2011) at two locations within and off the Rı ´a of Vigo (Station 1 and Station 3, respectively). Total abundance of zooplankton (NZ T ) varied annually following on average a unimodal cycle, with peak values between late spring and early autumn. In the long term, the time series of NZ T exhibited three contrasting periods: A) 1995 -2001, characterized by low abundance and low amplitude seasonality, with a stepped increase towards 2001; B) 2001 -2006, of high abundance and marked seasonality enclosing the maximum values of the time series; and C) 2006 -2010, of intermediate abundance and amplitude of the seasonal cycle. The most common taxonomic groups showed similar long-term and seasonal patterns. Principal component analysis revealed a shift in zooplankton dynamics from 2001 onwards, which affected annual averages and seasonality of all taxa. The observed changes in zooplankton dynamics were concomitant with sustained trends for upwelling intensity (increasing), precipitation (decreasing) and Gulf Stream North Wall position (equatorward) between 2000 and 2005. The results stress the importance of hydrodynamics, driven by meteo-climatic conditions, in the control of the abundance levels of zooplankton at seasonal and long-term interannual scales.

This paper investigates the possible underlying causes of the wide interannual fluctuations in catch of the common octopus Octopus vulgaris Cuvier, 1797 in one of the main small-scale fisheries off the coast of Galicia (northwest Spain). Galicia is at the northern boundary of the Iberian-Canary current upwelling system in the northeast Atlantic Ocean, where local winds induce seasonal upwelling, largely driving the annual cycles of primary and secondary production. We hypothesize that such dynamics are also fundamental for the survival of the planktonic stages of octopus and set the year class strength. We address this hypothesis by investigating the influence of upwelling on time-series of octopus fishery data. Wind stress structure during the spring-summer (prior to the hatching peak) and autumn-winter (during the planktonic stage) was found to affect the early life phase of this species, and explains up to 85% of the total variance of the year-to-year variability of the adult catch. Despite this bottom-up modulation via environmental conditions, our results also provide evidence for a between-cohort density-dependent interaction, probably caused by cannibalism and competition for habitat.

We used wavelet analysis that overcome the problems of nonstationarity in time series by performing a local time-scale decomposition of the signal Wavelet Transformation brought to you by CORE View metadata, citation and similar papers at core.ac.uk

This research aimed to assess the diversity and seasonal distribution of zooplankton from January to December 2024 and analyze its relationship with key physico-chemical parameters in Lakshmipuram Lake, a tropical freshwater body located in Anakapalli District, Andhra Pradesh. Samples were collected seasonally-pre-monsoon (March-May), monsoon (June-September), and post-monsoon (October-December)-using a 64 μm mesh plankton net. Samples were preserved in 4% formalin and analyzed in the laboratory using a Sedgwick-Rafter chamber under compound and stereo microscopes. Identification was performed using standard taxonomic keys. Concurrently, water samples were analyzed for various physico-chemical parameters including temperature, pH, turbidity, salinity, alkalinity, BOD, COD, nutrients, and more, following standard protocols. Microscopic analysis revealed five major zooplankton groups, comprising 26 species: Rotifera (10 species), Cladocera (8 species), Copepoda (3 species), Ostracoda (3 species), and Protozoa (2 species). Rotifera emerged as the most dominant group, followed by Cladocera and Copepoda. Seasonal variations indicated that post-monsoon conditions supported the highest species richness and abundance, while monsoon showed relatively lower densities likely due to unfavorable environmental conditions. The highest density of Cladocera was recorded in post-monsoon (441 Ind/L), while Rotifera peaked in summer (438 Ind/L). Diversity indices indicated ecological stability, with the Shannon-Wiener Index rising from 2.4890 (pre-monsoon) to 2.9957 (post-monsoon), and Simpson's Index values consistently above 0.93. Correlation analysis revealed water quality parameters, particularly salinity, conductance, and nutrient levels play a significant role in shaping zooplankton biodiversity. The study emphasizes the sensitivity of zooplankton diversity to water quality and underlines their role as bioindicators for aquatic ecosystem health. In conclusion, this study provides valuable baseline data on the zooplankton diversity of Lakshmipuram Lake, highlighting seasonal trends, ecological balance, and environmental influences, which are essential for future biomonitoring and conservation strategies.

Protists represent the majority of the eukaryotic diversity in the oceans. They have different functions in the marine food web, playing essential roles in the biogeochemical cycles. While the available data is rich in horizontal and temporal coverage, little is known on their vertical structuring, particularly below the photic zone. The present study applies V4 18S rDNA metabarcoding to samples collected over three years in conjunction with the BATS time-series to assess marine protist communities in the epipelagic and mesopelagic zones (0-1000 m). The protist community showed a dynamic seasonality in the epipelagic, responding to hydrographic yearly cycles. Mixotrophic lineages dominated throughout the year. However, autotrophs bloomed during the rapid transition between the winter mixing and the stratified summer, and heterotrophs had their peak at the end of summer, when the base of the thermocline reaches its deepest depth. Below the photic zone, the community, dominated by Rhi...

Particulate organic matter (POM) (fecal pellets) from zooplankton has been demonstrated to be an important nutrient source for the pelagic prokaryotic community. Significantly less is known about the chemical composition of the dissolved organic matter (DOM) produced by these eukaryotes and its influence on pelagic ecosystem structure. Zooplankton migrators, which daily transport surface-derived compounds to depth, may act as important vectors of limiting nutrients for mesopelagic microbial communities. In this role, zooplankton may increase the DOM remineralization rate by heterotrophic prokaryotes through the creation of nutrient rich “hot spots” that could potentially increase niche diversity. To explore these interactions, we collected the migratory copepod Pleuromamma xiphias from the northwestern Sargasso Sea and sampled its excreta after 12–16 h of incubation. We measured bulk dissolved organic carbon (DOC), dissolved free amino acids (DFAA) via high performance liquid chroma...

Updated checklist and zoogeographic remarks of benthic amphipods (Crustacea: Peracarida: Amphipoda) of two coastal lagoons in the western Lista de especies actualizada y notas zoogeográficas de anfípodos bentónicos (Crustacea: Peracarida: Amphipoda) de dos lagunas costeras en el golfo de México occidental

Cnidaria merupakan filum hewan beracun yang terbesar, namun racun dan bisa mereka belum mendapat perhatian ilmiah sebanyak racun dan bisa hewan darat (ular, kalajengking,laba-laba, dll.) dan bahkan beberapa hewan laut (misalnya siput kerucut). Sekitar 13.000 spesies cnidaria yang masih hidup telah dideskripsikan oleh para ahli sistematika. kini diketahui bahwa racun dari hewan laut ini dapat menjadi pemeriksaan molekuler yang sangat berguna untuk analisis saluran ion yang terlibat dalam pensinyalan listrik, respons imun, dan proses transduksi sinyal lain yang menarik secara biomedis. selama percobaan dengan ekstrak tentakel anemon laut dan hidrozoa. Demikian pula, baru-baru ini telah ditunjukkan bahwa racun dari anemon laut lain mampu menghambat proliferasi limfosit T secara ampuh dalam model penyakit autoimun tertentu. Dengan demikian, zat alami ini terus relevan untuk memahami dan mengobati penyakit manusia.

This work presents the results of a survey of the occurrences of jellyfish bycatch in trawling, bottom gill‐net, purse seine, and pole‐and‐line fishing gear in the main fishing port of southern Brazil Survey results are based on interviews conducted with fishers at the time of landing the catch. Historical data were also obtained on the peak occurrences of jellyfish in the last 20 years through interviews with fishers that had worked for up to 50 years in the area. Jellyfish were found to occur with the different fishing gear and to have preferential demersal behavior. The highest frequencies of occurrences were observed on the continental shelf and accompanied the trips of the fishing fleet at different times of the year. Hydrozoan jellyfish, presumably Rhacostoma atlanticum and Olindias sambaquiensis, were the most frequent and abundant species recorded during the period, but the historical data suggest peaks of occurrence every 10 years when dominant groups are replaced with othe...

We assessed the size variation of morphological traits in Bosmina freyi regarding changes in environmental variables, the biomass of invertebrate predators, and algal food availability in two depths of the photic zone, the riverine zone, and near the dam zone (lacustrine zone) in The Riogrande II reservoir. In 200 individuals of B. freyi, using the software TpsDig2 we measured the body size, mucron and antennule lengths, and the antennule aperture percentage. Using the Mann-Whitney U test, we assessed the differences between these traits considering the zones and the photic depths; however, we used a canonical discriminant analysis with morphologic traits and environmental variables. Measured morphological traits showed a heterogeneous distribution between sampled zones and depths (p < 0.05). The highest values mucron and antennule lengths and the smallest antennule aperture angle were observed on small body size individuals, associated with physical, chemical, and biological cha...

The present study investigates the relationship between hydrological connectivity and species diversity in a by-passed channel section, and in the adjacent water bodies of the Slovak-Hungarian Danube section (1,840.5-1,804.4 rkm). The study was designed to assess long-term temporal trends (from 1991 to 2013) in freshwater copepods assemblages and their ecological indices in different habitats of the Danube floodplain area. One of the purpose of this study was to monitor the species composition of copepods communities and ascertain their shift in various biotopes of the Danube floodplain system. Based on 23 years data, in the first step, the copepods habitat preferences using habitat values (HV) and indicator weights (IW), calculated from data collected over all the years of monitoring of planktonic communities of the Danube floodplain, were quantified. Subsequently, the floodplain index (FI) from a summary of the habitat values and indication weights of the current species was calculated, to evaluate changes in the connectivity of the anabranched section of the Slovak-Hungarian Danube. This confirmed the loss of active hydrological connectivity within the main river channel, ranging from the eupotamal to more or less isolated floodplain water bodies. Out of 50 recorded copepods species, 11 species manifest a preference for eupotamal habitats, 18 taxa preferred eupotamal B/parapotamal habitats and 21 species were found to prefer the plesiopotamal habitat type. The statistical analyses demonstrated that the structure of planktonic copepod communities in this area has changed since the Gabčíkovo hydropower plant was placed into operations. The NMDS analysis revealed shifts in the proportion of euplanktonic and tychoplanktonic species. Reversible community changes were found in the old river bed and in the eupotamal-B side arms.

The first findings and distribution of larvae of the species Diplophos proximus, family Gonostomatidae, in the Pacific of Colombia are presented. The analyzes show larvae between Bahía Málaga and Tumaco (limits with Ecuador), with low abundances during the seasons of September 2003 and 2005, July and December 2010, December 2013, February-March 2014, June 2016 and June and September 2017, always collected at stations located more than 113 km away from the coast and around Malpelo island. The larvae are elongated and have noticeable changes during development, initially oval eyes, poorly pigmented body without photophores and finallyrounded eyes, dorsal pigments and photophores during transformation. The present work contributes with information about distribution and ecology of larvae of D. proximus becoming the first records of catches for the Colombian Pacific, including the description of the larval stages found.

Appendicularians often constitute a significant portion of mesozooplankton tunicates in marine ecosystems. This study examines the spatial variations in the annual cycles of functional groups of planktonic Appendicularia in response to environmental changes within the Bay of Boka Kotorska. Monthly sampling over the course of a year during 2008/09 was conducted at seven stations, each characterised by distinct hydrographic conditions. Appendicularians exhibited spatial variations in their annual cycles across the seven stations. Based on these findings, it is proposed that the observed spatial variations in the annual cycles of functional groups of planktonic Appendicularia may reflect changes in hydrographic conditions. We present hydrographic data alongside information on the presence, abundance and distribution of eight species of two genera: Oikopleura dioica Fol, O. longicauda Vogt, O.fusiformis Fol, Fritillaria aequatorialis Lohmann, F. megachille Fol, F. pellucida (Busch), F. haplostoma Fol and F. borealis Lohmann. We also provide an overview of the occurrence of the dinoflagellate N. scintillans and its relationship with Appendicularia in the Bay of Boka Kotorska.

In this work, the thermal response of Mesocyclops ogunnus was experimentally studied. Temperature was the only one parameter that was tested. Other parameters, such as food quality and availability, light conditions, predation pressure, and water mass motions were not included in the study. Organisms were collected in Lake Kinneret and the experiments were carried out under diffused light, 12/12 hours light/dark conditions. In the experimental system, the organisms were exposed to different temperatures of 15˚C, 25˚C, 27˚C, and 30˚C with open pathway to migrate according to temperature preference. The preference of upper thermal range (25˚C, 27˚C, 30˚C) by copepodite and adult stages was documented.

Biofouling has destructive effects on shipping and leisure vessels, thus producing severe problems for marine and naval sectors due to corrosion with consequent elevated fuel consumption and higher maintenance costs. The development of anti-fouling or fouling release coatings creates deterrent surfaces that prevent the initial settlement of microorganisms. In this regard, new silica-based materials were prepared using two alkoxysilane cross-linkers containing epoxy and amine groups (i.e., 3-Glycidyloxypropyltrimethoxysilane and 3-aminopropyltriethoxysilane, respectively), in combination with two functional fluoro-silane (i.e., 3,3,3-trifluoropropyl-trimethoxysilane and glycidyl-2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9-hexadecafluorononylether) featuring well-known hydro repellent and anti-corrosion properties. As a matter of fact, the co-condensation of alkoxysilane featuring epoxide and amine ends, also mixed with two opportune long chain and short chain perfluorosilane precursors, allows g...

The influence of temperature, salinity, pH and dissolved oxygen on the temporal distribution of marine cladocerans at Escuro River estuary, Municipality of Ubatuba, SP, was analysed. Sampling nearest to the surf zone was carried out from July 2004 to June 2005. The cladoceran Penilia avirostris (Dana, 1852) was the dominant species and appeared throughout the sampled period. The species Pseudevadne tergestina (Claus, 1877) and Pleopis polyphemoides (Leuckart, 1859) were the less frequent and Pleopis polyphemoides has occurred mainly in the winter. A negative relationship was obtained for P. avirostris abundance and the water dissolved oxygen, probably as an indirect effect to the water turbulence. Pleopis polyphemoides had a negative relationship with the water temperature and positive with salinity and pH. Abundance of P. tergestina was associated only with salinity. Our findings suggest that P. avirostris is the most resistant species to the local environmental oscillations and th...

We studied the qualitative composition of zooplankton of the Kerid Crater Lake. We found 10 taxa from which five rotifers and two lower crustaceans. Three of the recorded species are new to the freshwater fauna of Iceland: the rotifer species Keratella cf. americana Carlin, 1943 and Colurella sulcata (Stenroos, 1898), and the crustacean harpacticoid Bryocamptus (Bryocamptus) minutus (Claus, 1863).

TRAYKOV, I. and M. VLADIMIROVA, 2015. Relationships between trophic state and physicochemical variables of some standing waterbodies on the territory of East-Aegean river Basin directorate, Bulgaria. Bulg. J. Agric. Sci., Supplement 1, 21: 126–136 The objectives of the study were to describe the physicochemical variables and to assess the trophic state of the reservoirs Ovcharitsa, Byal Kladenets, Skalitsa, Zhrebchevo and the fi shponds of Nikolaevo. Sampling was conducted at four occasions between April and August 2013. The concentrations of nutrients and the Carlson’s trophic state indices were used to assess the trophic state of the water bodies. The trophic state spans over several trophic categories – from oligo-mesotrophic to hypertrophic, with majority of the water bodies being eutrophic. Very strong positive correlation was observed between the transparency and the chlorophyl trophic state indices. Weaker, but still strong correlation was observed between the transparency an...

Mid-trophic pelagic fish are essential components of marine ecosystems because they represent the link between plankton and higher predators. Moreover they are the basis of the most important fisheries resources, for example in African waters. In this study we have sampled pelagic fish larvae in the Eastern Atlantic Ocean across a latitudinal gradient between 37°N and 18°S. We have employed Bongo nets for plankton sampling and conducted DNA analysis (Barcoding) for accurate species identification. From a total of 403 larvae we have identified 56 fish species. Some of them are cosmopolitan and others are latitude-specific, as expected. The latitudinal pattern of diversity did not exhibit a temperate-tropical cline; instead it was correlated with environmental conditions with a maximum in subtropical zones. These results are important in the context of ecosystem functioning and may serve for designing ecosystem-based management of fisheries resources.

Las actividades antropogénicas han derivado en un acelerado calentamiento global, que está elevando la temperatura media de la atmósfera terrestre y de los océanos. El mal manejo de las actividades productivas en los océanos ha resultado en problemas ambientales como la sobrepesca y la contaminación, afectando negativamente la distribución y las dinámicas poblacionales de muchas especies de fauna marina. Una de las especies importantes en el ecosistema pelágico es el dorado (Coryphaena hippurus), uno de los principales depredadores marinos cuya función ecológica es controlar las poblaciones de peces herbívoros, manteniendo así el equilibrio de la trama alimenticia. Por ello, la extinción de esta especie podría producir un desequilibrio de tipo “top-down” en el ecosistema pelágico. Esta investigación tiene el objetivo, por primera vez, modelar la distribución potencial actual del dorado (C. hippurus) a lo largo de toda la costa del Pacífico mexicano mediante el algoritmo de Máxima Entropía (MaxEnt), a partir del contraste de factores ecológicos y climáticos con los registros de la especie reportados en bases de datos científicas como SNIB-CONABIO (Sistema Nacional de Información en Biodiversidad-Comisión nacional para el Uso y Conocimiento de la Biodiversidad) y Gbif. Los resultados sugieren que el dorado (C. hippurus) se distribuye a lo largo de toda la costa del Pacífico mexicano, ampliando así el área de distribución anteriormente reportada en la literatura científica para el norte de la costa de los Estados Unidos de América. Las tres variables que más contribuyeron a explicar el modelo de distribución potencial fueron la Temperatura Máxima a Mínima Profundidad, la Temperatura Mínima a Media Profundidad, y el Nitrato con un Rango a Máxima Profundidad. Estos resultados proporcionan información clave para determinar las áreas prioritarias de conservación (manejo sustentable) del dorado (C. hippurus) en la costa mexicana, así como las variables ambientales que influyen en su distribución.

We analyzed and compared Mediterranean mesozooplankton time series spanning 1957-2006 from six coastal stations in the Balearic, Ligurian, Tyrrhenian, North and Middle Adriatic and Aegean Sea. Our analysis focused on fluctuations of major zooplankton taxonomic groups and their relation with environmental and climatic variability. Average seasonal cycles and interannual trends were derived. Stations spanned a large range of trophic status from oligotrophic to moderately eutrophic. Intra-station analyses showed (1) coherent multi-taxa trends off Villefranche sur mer that diverge from the previous results found at species level, (2) in Baleares, covariation of zooplankton and water masses as a consequence of the boundary hydrographic regime in the middle Western Mediterranean, (3) decrease in trophic status and abundance of some taxonomic groups off Naples, and (4) off Athens, an increase of zooplankton abundance and decrease in chlorophyll possibly caused by reduction of anthropogenic nutrient input, increase of microbial components, and more efficient grazing control on phytoplankton. (5) At basin scale, the analysis of temperature revealed significant positive correlations between Villefranche, Trieste and Naples for annual and/or winter average, and synchronous abrupt cooling and warming events centered in 1987 at the same three sites. After correction for multiple comparisons, we found no significant correlations between climate indices and local temperature or zooplankton abundance, nor between stations for zooplankton abundance, therefore we suggest that for these coastal stations local drivers (climatic, anthropogenic) are dominant and that the link between local and larger scale of climate should be investigated further if we are to understand zooplankton fluctuations.

Hyperiid amphipod species from the Gulf of Ulloa, Baja California, and the adjacent region (from the shelf break to 200 km offshore) were analyzed to evaluate diversity and abundances. This productive area supports small-scale commercial fisheries, including sand bass (Paralabrax nebulifer), California spiny lobster (Panulirus interruptus), abalones, clams, and others. Strong coastal upwelling events were observed during summer seasons of the period 2002-2008 between Punta Eugenia and Punta Abreojos. The upwelling plumes at Punta Abreojos are transported southward in slope waters bordering the coastal shelf of the Gulf of Ulloa, contributing to the separation of coastal and oceanic regions, and explain differences in amphipod diversity and abundances between both regions. In the offshore region, the most abundant species were Vibilia armata, Lestrigonus schizogeneios, Primno brevidens, and Eupronoe minuta, similar to previous findings in northern regions of Baja California and southern California. However, abundances of these species were lower (10-30 individuals/1000 m 3), only reaching 20-50% of abundance levels reported off northern Baja California. In the coastal shelf of the Gulf of Ulloa, amphipods were virtually absent

Interannual changes in the assemblages of hyperiid amphipods during the period 2002 to 2008 are analyzed for the first time in the coastal Pacific area comprised between Ensenada (32°N) and Punta Baja (30°N), Baja California, Mexico. The study period witnessed diverse climatic events, such as a subarctic water intrusion in 2002, three El Niño events (in 2002-2003, 2004-2005, and 2006-2007) and one La Niña event in 2007-2008. Multivariate analysis of summer hyperiid amphipods based on the Bray-Curtis similarity index indicated that July 2005 contrasted with the rest of the summer seasons, showing a low abundance of amphipods, characterized particularly by the scarcity of Lestrigonus schizogeneios. The second most different summer was July 2002, characterized by the increased abundance of Primno brevidens and the presence of the subarctic species Themisto pacifica. Despite the marked decrease of L. schizogeneios in 2005, this species showed a pronounced recovery in 2006. Therefore, physical conditions under the influence of El Niño did not appear to be a direct factor in changing the abundances of L. schizogeneios, and the collapse of its populations during July 2005 could be the result of strong predation on small Lestrigonus juveniles by euphausiids, which were extremely abundant in spring and summer 2005. With the exception of 2005, the dominant species were relatively constant. Similarity analysis revealed a core contribution of the characteristic subtropical species in the California Current System (L. schizogeneios, P. brevidens, Vibilia armata, and Eupronoe minuta), indicating a resilience of these key species to climatic events.

Current system is a large marine ecosystem with transition gradients between subarctic and trop-25 ical biomes containing diverse habitats. Biogeographic species groups must be carefully analyzed in order to de-26 tect tendencies shifting the ecosystem toward a more temperate or tropical state. Species composition of hyperiid 27 amphipods was analyzed in July 2002 for evidence of subarctic water intrusion and for signals of the El Niño 28 event developing in the equatorial Pacific. Multivariate analysis showed a dominance of "transition zone" species 29 typical of the California Current. The main evidence of subarctic water intrusion was the extended distribution of 30 Themisto pacifica, which reached as far south as 27°N, with particularly high abundances at 30-32°N. The intru-31 sion of subarctic water took place despite evidence that an El Niño event was in progress. The zonal advection due 32 to El Niño intersected the equatorward flow of the subarctic intrusion and probably produced a large cyclonic 33 eddy off Baja California. This eddy maintained a limited El Niño influence at a few offshore stations near its south-34 ern boundary. The main environmental variables influencing the amphipod assemblage structure were water 35 temperature and the abundance of salps. T. pacifica, a species with cool water affinity, was more sensitive to tem-36 perature, whereas subtropical species, such as Vibilia armata, were strongly correlated with the availability of 37 salps.

Hyperiid amphipods collected during 4 IMECOCAL (Spanish acronym for Mexican Investigations of the California Current) cruises in January, April, July, and October 2005 were analyzed for seasonal variation in abundance and diversity and to determine the influence of surface circulation. The number of species was high in all seasons (between 79 and 92), but abundances showed remarkable differences. The total number of amphipods was lowest in January and highest in October (geometric means were 82 and 606 ind. 1000 m -3 respectively). Multivariate analysis based on similarity indices demonstrated a tight coupling between species composition and mesoscale structures. The largest cluster joined 67 stations, with 40% of similarity being explained by 4 species (Vibilia armata, Lestrigonus schizogeneios, Eupronoe minuta, and Primno brevidens). The geographic position of these stations coincided with the main California Current (CC) flow from spring to autumn. Subgroups were defined by minor seasonal differences. In contrast, the CC flow during winter was reduced to a meander off north Baja California, and was surrounded by oligotrophic water as indicated by the presence of the hyperiids Anchylomera blossevillei and Phrosina semilunata plus 3 of the dominant species (V. armata, E. minuta, and P. brevidens). To the south of this front, other clusters with high oceanic influence were formed. In 2005, 3 eddies were detected in the area: one anticyclonic eddy in April and 2 cyclonic eddies in July. The anticyclonic eddy located in the southwest had its own faunal cluster that had high diversity but low population density. The main species in the anticyclonic eddy was Platyscelus ovoides. Only one of the cyclonic eddies had a unique faunal identity, being strongly dominated by Vibilia armata; this was located in the north between the CC flow and the coast. The other eddy was large and situated in the middle of the area, with a faunal array analogous to that in the CC flow. Correlation between hyperiid and salp species abundances suggested that the increase in salps (Salpa fusiformis, Thalia orientalis, Cyclosalpa bakeri) in spring could be relevant, as many hyperiid species showed a strong increase at this time. However, the most correlated salp was Cyclosalpa danae, which occurred only in October. Chains of C. danae aggregates were firmly attached in the samples. This would promote the aggregation and survival of amphipod hosts, particularly small species such as Lestrigonus schizogenios and L. bengalensis.

Bulgaria features a remarkable biodiversity owing to its geography and climate. At the same time it is much vulnerable to the introduction of alien plant and animal species. In the current paper we make a review of the information about alien species in Bulgaria (number of introduced species, pathways of introduction, status and impact of introduced populations), as well as policy, project, research and awareness raising activities related to alien species. So far the alien species within the reviewed taxonomic groups account for 340 vascular plant species, 347 terrestrial arthropods, 31 marine invertebrates, 3 freshwater bivalves, 23 freshwater fish, 1 reptile, 14 bird and 9 mammal species. About 12% of the alien vascular plant species, 25% of the aquatic species, 35% of the terrestrial arthropods, and 50% of the bird species were recorded after 2000. The main pathways of introduction of the alien species to Bulgaria and their further spread on the territory of the country include ...

The Allen Paradox is the observation that, in aquatic communities, there is insufficient prey production to support predator growth. An assessment of the literature reveals that this paradox remains apparent in one of every four studies. Here, a novel explanation for this paradox is proposed: predators that feed in a spatially-heterogeneous-prey environment (SHPE) may experience a greater net energy gain than in a corresponding uniform-prey environment (UPE), meaning that predators may require less food than has been traditionally perceived. A model wasdeveloped to simulate a predator’s energy gain while feeding in a SHPE rather than a UPE. According to the simulation, a greater net energy gain in a SHPE than a UPEis possible, but only under certain conditions. Since prey can be utilized more efficiently in a SHPE, a given amount of prey production can supply more predator growth, which can have positive implications in fish stocking.

Se describe la distribución espacial y abundancia de diatomeas pertenecientes al género Pseudo-nitzschia en la cuenca pacífica colombiana (CPC) durante la campaña oceanográfica PACÍFICO XLIV- ERFEN XLII, evaluando su comportamiento frente a las variables de temperatura y salinidad. Se realizaron muestreos de fitoplancton (con botellas Niskin de 5 L) a dos profundidades (superficial y 50 m) en 25 estaciones. Se observó que en superficie se registraron las mayores abundancias del género distribuyéndose especialmente en la zona intermedia de la CPC. Este patrón de distribución coincidió con valores bajos de temperatura y altos en salinidad. Debido a lo anterior, se encontraron diferencias significativas en la abundancia de Pseudo-nitzschia entre las dos profundidades de estudio (Mann- Whitney test, p = 0.001). Se estableció una relación directa entre la salinidad y la abundancia del género (r = 0.50; p = 0.01), indicando la afinidad de estas algas por ambientes con altas salinidades, mientras que la temperatura mostró un comportamiento inverso con la abundancia (r = -0.42; p = 0.043). Aunque los valores de correlación no son muy altos, la distribución espacial de variables bióticas y abióticas, sugieren la influencia de la salinidad y temperatura en la abundancia y distribución de Pseudo-nitzschia.

La isla Malpelo conforma la ecorregión insular del Pacífico colombiano y contiene un mosaico de ecosistemas terrestres, litorales y submareales únicos. Considerando su carácter insular es de esperar que las características oceanográficas en esta localidad se encuentren influenciadas por la dinámica física y química del Pacífico Oriental Tropical (POT), siendo moduladas por las condiciones propias de la Cuenca Oceánica del Pacífico Colombiano (COPC). En este trabajo, se utilizó información in situ para describir las condiciones termohalinas de la columna de agua en la isla Malpelo e identificar las masas de agua dominantes durante los dos períodos hidroclimatológicos característicos de la COPC. Adicionalmente, se analizó la variabilidad térmica y halina en el COPC y se definió el campo de circulación geostrófico superficial a partir de información oceanográfica in situ durante los mismos períodos de tiempo con el propósito de evaluar su efecto sobre las condiciones oceanográficas en el ambiente pelágico de la isla Malpelo.

Centrorhynchus kuntzi Schmidt and Neiland, 1966, reported here for the first time from the USA, occurred in Bubo virginianus in Florida and Buteo jamaicensis, Buteo lineatus, and Buteo platypterus in Louisiana. Centrorhynchus kuntzi males, previously undescribed, were 10 to 29 mm long with a large swelling near the anterior end of the trunk. The proboscis, averaging 1.14 mm in length and with a marked swelling near the middle at the level of proboscis receptacle insertion, was armed with 26 to 31 (usually 29) longitudinal rows of 22 to 26 (usually 24) hooks each. The first seven to nine (usually 8) hooks in each row possessed long, simple roots and the following 14 to 18 (usually 16) were rootless spines. Centrorhynchus spinosus (Kaiser, 1893) Van Cleave, 1924, occurred in Melanerpes carolinus in Louisiana and Strix varia in Florida and Louisiana. Centrorhynchus spinosus resembles C. kuntzi in the range in number of longitudinal rows of proboscis hooks, although C. kuntzi usually po...

Se registran dieciséis especies de copépodos planctónicos de la Laguna Navío Quebrado, en La Guajira, Colombia. Las muestras de zooplancton fueron recolectadas de la zona litoral con vegetación (macrófias y mangles) y de aguas abiertas asociadas a un banco de ostras. La mayoría de las especies fueron registradas en el área relacionada con las macrófias. Una de ellas, Halicyclops exiguus Kiefer, 1934, es nueva para la fauna de copépodos de Colombia; se proporciona un análisis morfológico comparativo e ilustraciones de esta especie. La composición general de la comunidad local de copépodos incluye formas marinas, estuarinas y de aguas dulces, que son representativas del amplio gradiente de salinidad (0-28) encontrado en el área de estudio. Este es el primer registro de la fauna de copépodos planctónicos en este sistema. Se proporcionan comentarios sobre la morfología y fotografías de especies seleccionadas.

El estudio del zooplancton en la zona costera es fundamental para entender los procesos ecológicos. La zona costera Arapito - Santa Fé, ubicada en el Parque Nacional Mochima, estado Sucre, Venezuela, es considerada un área de gran importancia natural y por ello se planteó el estudio sobre el zooplancton. En este sentido, se determinó la composición y estructura comunitaria del zooplancton, en 20 estaciones, separadas en a) estaciones costeras y b) alejadas de la costa, durante diciembre 2008. Las muestras fueron recolectadas arrastrando oblicuamente una red de Bongo (500 y 300 μm, con flujómetro). La comunidad estuvo caracterizada por la presencia de organismos holoplanctónicos y en menor proporción de meroplancton. Los principales grupos holoplanctónicos fueron cladóceros, copépodos y plancton gelatinoso (apendiculados, sifonóforos e hidromedusas). Las especies más abundantes fueron los cladóceros Penilia avirostris y Pseudevadne tergestina y los copépodos Acartia tonsa y Temora turbinata. El alto porcentaje de holoplancton en la zona de estudio permite considerarla como una zona de crecimiento y alimentación. El ANOSIM-MDS, mostró diferencias significativas (p<0.05) entre los dos ambientes con R=0.27 pero con baja disimilitud (17.4%), lo que sugiere que procesos de mezcla promueven la distribución homogénea del zooplancton en la zona de estudio.