Freshwater Ecology Research Papers - Academia.edu (original) (raw)

Freshwater bodies (springs, streams, rivers, and wetlands) are important ecosystems that provide food and habitat to a wide range of aquatic and terrestrial species, including invertebrates, and support disproportionately high levels of biodiversity compared to their spatial coverage (Heino et al. 2009). Aquatic invertebrates play an important role in nutrient cycles, primary productivity, decomposition, and translocation of materials. As consumers at intermediate trophic levels, they are influenced by both bottom-‐up and top-‐down forces, serve as the conduits of these forces, and are an important food source for fish. The many roles performed by aquatic invertebrates underscore the importance of their conservation (Wallace and Webster 1996). Aquatic invertebrate assemblages are also good indicators of environmental change because they are long-‐term inhabitants of lotic and lentic systems, relatively immobile, easy to collect, and respond predictably to environmental stresses, whether human induced or climatic. Aquatic invertebrates discussed here are primarily lotic insects and lotic/lentic mollusks. Very little information exists concerning lentic insects in the study area, thus they are not covered here. In general, the species found in the streams and rivers of central and south-‐central Oregon are widely distributed and common in western North America. Endemic or isolated insect species may be found to occur in springs and small streams in the alpine/subalpine zone along the Cascade crest as invertebrates of these habitats have not been well documented. A number of mollusk species with restricted ranges are known from groundwater-‐fed springs in the Deschutes and Klamath basins. Cold springs support aquatic mollusk and some insect species that are exclusively adapted to and confined to this habitat. Climate-‐driven shifts are expected in the diversity and composition of communities as limiting habitat thresholds, such as water temperature, move longitudinally along a river. While many aquatic invertebrate taxa are predicted to contract or expand their range and abundance depending on their habitat tolerance, the most climate change vulnerable habitat types for aquatic invertebrates in central and south-‐central Oregon are the alpine/subalpine streams and wetlands, and forested headwater streams and springs.

- by
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- Freshwater Ecology, Freshwater Mollusks, Freshwater invertebrates
- by Antoine Legault
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- Zoology, Ecology, Freshwater Ecology, Freshwater fish ecology

Food habits of co-occurring largemouth bass (Micropterus salmoides) and spotted bass (M. punctulatus) were documented in two New Mexico reservoirs, Brantley Lake and Sumner Lake, from May 2001 to May 2002. In Brantley Lake, bass ate mainly fish, whereas bass in Sumner Lake ate mainly crayfish. Food habits of both species varied seasonally and there was substantial overlap in the

- by Rahma Deny
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- Biology, Ecology, Freshwater Ecology, Seasonality

Science popularization paper briefly introducing the diatom identification volume: Freshwater Benthic Diatoms of Central Europe (FBDCE): Over 800 Common Species Used in Ecological Assessment. M. Cantonati, M.G. Kelly & H. Lange-Bertalot (Eds.): 942 pp. Koeltz Botanical Books (ISBN 978-3-946583-06-6). English edition with updated taxonomy and added species of: Hofmann G., Werum M. & Lange-Bertalot H. 2013. Diatomeen im Süßwasser-Benthos von Mitteleuropa. Bestimmungsflora Kieselalgen für die ökologische Praxis. Über 700 der häufigsten Arten und ihre Ökologie. Lange-Bertalot, H. (Ed.): 908 pp. 2. korrigierte Aufl. Koeltz Botanical Books.
The principal goal of this volume is to provide an effective tool for diatom identification in applied ecology (diatom-based assessments and monitoring, environmental sciences etc.).

- by Marco Cantonati
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- Environmental Science, Environmental Studies, Freshwater Ecology, Diatom taxonomy

1.The nature and extent of spatial pattern in communities has important implications for their dynamics and conservation. Previous studies of pond ecosystems, over relatively small spatial scales, have found little evidence of spatial autocorrelation of community composition. Patterns in community composition over greater spatial distances have not been documented.2.Here, data on macroinvertebrate communities and physico-chemical characteristics of 102 ponds over a 60 × 60 km area of Oxfordshire, UK, were used to examine evidence for spatial autocorrelation in community composition and to separate the effects of environmental similarity and physical distance on community similarity.3.Overall similarity between communities was low, but showed significant positive spatial autocorrelation. There was evidence for both environmental and physical distance effects on spatial autocorrelation of community similarity. Community similarity was negatively related to differences in environmental conditions, but effects were only significant for large environmental differences.4.When environmental effects were accounted for, there was significant positive spatial autocorrelation of community composition over inter-site distances of up to 13 km. These results suggest that interactions between pond sites, potentially through dispersal, are evident over larger spatial scales than has previously been appreciated, and emphasize the need to consider spatial issues when developing strategies for pond conservation. Copyright © 2005 John Wiley & Sons, Ltd.The nature and extent of spatial pattern in communities has important implications for their dynamics and conservation. Previous studies of pond ecosystems, over relatively small spatial scales, have found little evidence of spatial autocorrelation of community composition. Patterns in community composition over greater spatial distances have not been documented.Here, data on macroinvertebrate communities and physico-chemical characteristics of 102 ponds over a 60 × 60 km area of Oxfordshire, UK, were used to examine evidence for spatial autocorrelation in community composition and to separate the effects of environmental similarity and physical distance on community similarity.Overall similarity between communities was low, but showed significant positive spatial autocorrelation. There was evidence for both environmental and physical distance effects on spatial autocorrelation of community similarity. Community similarity was negatively related to differences in environmental conditions, but effects were only significant for large environmental differences.When environmental effects were accounted for, there was significant positive spatial autocorrelation of community composition over inter-site distances of up to 13 km. These results suggest that interactions between pond sites, potentially through dispersal, are evident over larger spatial scales than has previously been appreciated, and emphasize the need to consider spatial issues when developing strategies for pond conservation.

- by Jeremy Biggs
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- Freshwater Ecology
- by gary grossman
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- Ecology, Fish Biology, Freshwater Ecology, Animal Ecology
- by gary grossman
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- Ecology, Fish Biology, Freshwater Ecology, Animal Ecology
- by Chris Pennuto
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- Environmental Science, Ecology, Freshwater Ecology, Seasonality
- by antonella lugliè
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- Climate Change Adaptation, Freshwater Ecology
- by catia monauni
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- Ecology, Freshwater Ecology

Abstract Here we report the first molecular data on an invasive Sinanodonta woodiana ( Lea, 1834 ) (Bivalvia: Unionidae) population from Lesser Sundas (Flores Island, Indonesia). The DNA barcoding reveals that this population belongs to a mitochondrial lineage that is widely distributed across Malaysia. The mean COI p -distance between this ‘tropical’ lineage and invasive European populations is 5.3 ± 1.0% which clearly corresponds to the interspecific difference. The representatives of such a ‘tropical’ lineage have likely invaded other Indonesian islands together with the introduction of their host fish species, because our sequenced specimens were taken from a population on the southeastern edge of the current Sinanodonta distribution. The molecular identification of invasive populations of the Chinese pond mussels using available online databases such as the BOLD IDS and NCBI's Genbank is doubtful, because there are at least seven distinct mitochondrial lineages, hence each of them could belong to a separate cryptic taxon.

- by Mikhail Gofarov
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- Technology, Indonesia, Freshwater Ecology, Biological invasions

Worldwide, cassava (Manhiot esculenta Crantz) is used for a multitude of reasons; as a main food staple in Africa (Nigeria, Ghana, Cameroun etc.), Asia (Indonesia, Thailand, Cambodia etc.) and South America (Bazil, Paraguay etc.) as well as a source of energy for biogas and biofuel in Asia (China, Indonesia etc), South America (Brazil, Columbia etc.). A high demand of energy due to rapid urbanisation and development in developing countries, prompted governments, scientists and NGOs to seek other environmentally benign methods of energy production than fossil fuel based energy production systems. Thus, cassava has been identified as one of the suitable crops for biogas and biofuel production in order to mitigate the ensuing high energy demand. Like many developing countries, South Africa is interested in achieving sustainable energy and food supply, and cassava can serve as a source of both bioenergy bioethanol and biogas as well as food. However, the establishment/perennial production of cassava in developing countries generally and in South Africa particularly is facing potential challenges such as infertile land, pests problems, climate change and land availability for cultivation. However, some of this challenges can be overcome through availability of land for cassava cultivation, pest (insects) control, creation of local markets leading to job opportunities and communities acceptance of the crop for self-nourishment and industrial use.

- by Elie F. Itoba Tombo
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- Agronomy, Ecology, Agriculture, Environmental Impact Assessment

Cyanophytes were sampled in two surveys, summer 1993 and 1995, in order to compare the algal flora of 19 small springs located in the upper part of the River Sarca catchment (Northern Italy). Measurements of the main physico-chemical variables of the spring water were also carried out. The springs differ largely in altitude (from 1073 to 2130 m a.s.l.), lithology of the aquifer (calcareous/dolomitic mountains in the Brenta and igneous intrusive rocks in the Adamello region), discharge (from less than 1 to 137 l s-1), substrate particle size and exposure. Cyanophytes were present in all the rheocrenes and lacking in the helocrenes. Up to 41 cyanophyte species were observed. The genera Chamaesiphon, Homoeothrix and Phormidium were most frequent and rich in species, with a majority of epilithic taxa occuring mainly in oligotrophic fast flowing mountain streams. Sample grouping as obtained by numerical analysis (TWINSPAN, CANOCO) was mainly explained by lithology and conductivity (separation of siliceous from calcareous substrate). Other variables pointed out by the Canonical Correspondence Analysis were the degree of shading and altitude. Differences among springs are marked, as can be argued from the relation between the high total number of species found (41) and the low diversity (on the average six species) of the single sites. Rare species were mainly found in springs warranting low flow variability at the site of emergence.

- by Marco Cantonati
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- Limnology, Cyanobacteria, Freshwater Ecology, Benthic Ecology
- by Martin Pusch
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- Engineering, Earth Sciences, Freshwater Ecology, Biological Sciences
- by Claudio Liberato
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- Ecology, Freshwater Ecology, Medical Entomology, Italy
- by gary grossman
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- Ecology, Fish Biology, Freshwater Ecology, Animal Ecology
- by Angela Sanseverino
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- Freshwater Ecology, Trophic Ecology, Chironomidae

Freshwater biodiversity is declining dramatically, and the current biodiversity crisis requires defining bold goals and mobilizing substantial resources to meet the challenges. While the reasons are varied, both research and conservation of freshwater biodiversity lag far behind efforts in the terrestrial and marine realms. We identify fifteen pressing global needs to support informed global freshwater biodiversity stewardship. The proposed agenda aims to advance freshwater biodiversity research globally as a critical step in improving coordinated action towards its sustainable management and conservation.

- by Francis S. Magbanua
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- Ecology, Freshwater Ecology, Social Ecology, Crisis
- by Meghan Duffy
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- Aquatic Ecology, Community Ecology, Disease ecology, Freshwater Ecology
- by Gabriel Colbeck
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- Zoology, Ecology, Freshwater Ecology, Freshwater fish ecology
- by Hugh Jones and +1
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- Conservation, Freshwater Ecology, Hyriidae, Threatening Processes
- by Julian D Reynolds
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- Ecology, Crayfish Ecology, Freshwater Ecology

• Mediterranean marshes are highly diverse in macroalgae despite high nitrogen levels • Macroalgal assemblages can be used to evaluate ecological quality of Mediterranean marshes • These systems are severely threatened by human activities and climate change • Mediterranean marshes deserve to be protected and better studied as sentinels of climate change a b s t r a c t Although Mediterranean marshes have historically suffered high anthropogenic pressure, they have maintained their remarkable biodiversity. They are severely threatened but remain comparatively unexplored systems from the algological point of view. For example, most of the indexes proposed for monitoring ecological quality are based on diatoms and very few have explored the use of macroalgae. The Pego-Oliva marsh is located in the east of the Iberian Peninsula close to the Mediterranean coast with warm annual temperature and fairly high precipitation. The aims of this study were to ascertain the ecological variables that explained macroalgal distribution in the Pego-Oliva marsh and to assess their indicator value. Macroalgal biodiversity was seen to be high (50 taxa) despite the high nitrogen concentration of the marsh. All the environmental variables studied had a broad range of variation throughout the marsh, especially conductivity (500–12290 μS/cm), temperature (14.3–31.7°C), nitrate (9.493–64.113 mg/L) and ammonium (0.004–0.814 mg/L). A clear gradient of conductivity and dissolved oxygen was observed from fresh to saltwater. Batrachospermum arcuatum, Calothrix parietina, Chaetophora tuberculosa, Draparnaldia mutabilis, Hildenbrandia angolensis and Leptolyngbya angustissima were seen to act as indicators of low conductivity and dissolved inorganic nitrogen, and high dissolved oxygen, while Calothrix pulvinata, Ulva intestinalis, Homoeothrix violacea, Phormidium tergestinum and Thorea violacea were indicators of high conductivity and low dissolved nitrogen habitats. Cladophora glomerata, Compsopogon coeruleus, Polysiphonia subtilissima and Ulva flexuosa are the most widespread species and have a broad ecological range. Irrigation ditches have high ammonium and low dissolved oxygen concentrations and host infrequently reported species like Kumanoa mahlacensis. The data presented confirm the usefulness of macroalgae for the ecological monitoring of marshes, while increasing our knowledge of the distribution and ecological range of some species. However, more experimental work is needed to know the tolerance range of species living in dynamic systems like Mediterranean marshes.

- by Marina Aboal
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- Freshwater Ecology, Biodiversity, Biodiversity Conservation, Macroalgae

A variety of chemicals including foaming agents are used to aid in the protection of forest resources from the wild land fires. The fire-fighting foams (FFFs) are formulations composed principally of surfactants. As a part of Japanese national project, environmentally inert FFFs have been developed. There is an emerging need for testing the impacts of these FFFs on the living organisms composing the typical landscapes or ecosystems in Japan. In the present report, we aimed to describe our latest attempt for assessing both the short-tem and long-term impacts of FFFs in aquatic (fresh water) and semi-aquatic (wetland) ecosystems , by employing the laboratory-sized model assays (preliminary studies) and the biotope-based observation, respectively. In the biotope assays which was based on the observation in compact biotopes mimicking the fresh water environments and wetland, both the acute and long-term eco-toxic impacts of two FFFs (soap-based and synthetic detergent-based) were assessed. Spraying of synthetic detergent-based foam formula was shown to be more toxic compared to soap-based formula and mock water treatment.

- by Tomonori Kawano
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- Environmental Engineering, Landscape Ecology, Marine Biology, Microbiology
- by ZRELLI SONIA
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- Freshwater Ecology, Evolutionary Ecology, Systematic Entomology, Ephemeroptera
- by gary grossman
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- Ecology, Fish Biology, Freshwater Ecology, Animal Ecology

In 1992-2000 a total of 1441 specimens of bream Abramis brama from
four reservoirs of the Volga River basin were captured and examined. A
positive correlation between the level of fish parasites infection by Ligula
inteslinalis (L.) and Digramma interrupta (Rud.) and place in the cascade
of freshwater bodies has been revealed. A relative stability of the prevalence of helminths at the low level in three Upper Volga reservoirs was registered. On the contrary, a maximal number of plerocercoids was found in the Gorky Reservoir (Middle Volga basin). The prevalence of cestodes is great in low section of the reservoir in comparison with others water bodies. In the last years the quota of D. interrupta plerocercoids in total number of cestodes has greatly increased to 30-40% in Rybinsk and Gorky reservoirs.

- by Andrey V . Tyutin
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- Fish Biology, Freshwater Ecology

Abstract: Macro-invertebrates form an integral part of aquatic systems, and assessment of macro-invertebrate communities is one of the best ways to monitor the health of a stream. Despite this, stream monitoring of macro-invertebrates has been extremely limited in Bhutan. A study was conducted to generate baseline information on macro-invertebrate diversity in the Phobjikha valley, covering community composition and seasonal variation in diversity during post and pre-monsoon seasons. From a total of 244 units sampled in streams, 50 families from 13 orders were recorded. The dominant order overall was Ephemeroptera (31%), which also dominated the premonsoon assessment (33%), while Trichoptera (39%) dominated the post-monsoon assessment. The pre-monsoon assessment recorded two additional orders, Caenogastropoda and Veneroida. There was no significant difference in diversity between the post-monsoon and pre-monsoon assessments (p˃0.3), but a significant difference in species diversity between seasons was observed in pools and riffles. Physicochemical parameters indicated that pH, electrical conductivity and salinity were within favorable ranges for macro-invertebrates. Further studies of other habitats in different seasons will produce a more comprehensive understanding of macro-invertebrate diversity.

- by Jigme Wangchuk and +1
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- Freshwater Ecology, Freshwater fish taxonomy

this article is about all Ultimate Guide to Marimo Moss Balls. In this article talks all about keeping, cultivating, carrying and tips of marimo moss balls in the freshwater tank. Please visit our site aquascaper.org for more information... more

- by Angela D. Calvillo
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- Business, Botany, Aquatic Ecology, Conservation Biology
- by Sumit Dookia
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- Entomology, Herpetology, Environmental Education, Science Communication

1. The North American signal crayfish Pacifastacus leniusculus has been widely introduced throughout Europe where it is expanding its range and in many areas replacing the native white-clawed crayfish Austropotamobius pallipes. There is concern with regards to the impact of this species replacement on benthic fish. Interspecific behavioural interactions and competition for shelter between the benthic fish, bullhead Cottus gobio and A. pallipes and P. leniusculus were measured to assess the comparative impact of native and non-native crayfish. 2. Both white-clawed crayfish and signal crayfish were dominant over bullhead. Bullheads moved away from approaches of crayfish, left shelters on entry of crayfish and rarely entered an occupied shelter. Signal crayfish made significantly more aggressive approaches towards bullheads than white-clawed crayfish. 3. Alone, bullheads spent most of their time by day under shelter (median 96%), reflecting a highly entrained behavioural response, which was relaxed by night (median 60%). Both crayfish species reduced shelter use by bullheads although the extent of shelter sharing by bullheads was higher in trials with white-clawed crayfish than with signal crayfish. 4. Sampling in the River Wharfe, northern England, where signal and white-clawed crayfish and bullhead currently exist, demonstrated a negative relationship between the densities of signal crayfish and bullhead, with high bullhead abundance where crayfish were absent or where white-clawed crayfish were present at low density. 5. Assuming that shelter is sometimes limited under natural conditions, crayfish are likely to displace bullheads from shelters, which may increase predation risk for bullheads. Although the effects of signal crayfish on bullhead shelter use were more intense, the pattern was highly evident for the native white-clawed crayfish. The higher fecundity and densities attained by signal crayfish may be more significant than differences in the behaviour of the two crayfish species in determining the impact of crayfish on bullheads.

Radio-telemetry was used to study the late autumn and winter movements of twenty adult signal crayfish Pacifasta-cus leniusculus (32.9–63.8 mm carapace length) an introduced exotic crayfish species, in the upland River Wharfe, northern England. The distances moved during the study varied greatly between individuals (0–328 m). Movements were generally sporadic; crayfish would remain in one position for several weeks and make occasional movements to new locations. Total distances travelled, linear range and ranging area did not differ significantly between males and females. The distance travelled in upstream and downstream directions did not differ significantly and there was no correlation between distance travelled and crayfish size. Several high flow events occurred during the study, but these did not cause any mortality or apparent displacement of crayfish downstream, suggesting that this is not a significant factor in downstream dispersal or mortality of adults of this invasive crayfish species in winter. A marked reduction in large-scale movements occurred in mid-December which coincided with a decline in water temperature. There was a less distinct pattern in local activity which was strongly correlated with water temperature and varied before and after mid-December.

- by Martyn Lucas
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- Limnology, Conservation Biology, Spatial Ecology, Invasive species ecology
- by Joe Caffrey and +2
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- Management, Earth Sciences, Phylogeography, Population Genetics

A study was carried out on the diversity and density of aquatic insect
community in the two urban temple ponds – Radhamadhav akhra pond
and Mandir dighi pond of Silchar town, Assam, Northeast India. All total
22 taxa of aquatic insects were recorded, 13 taxa from Radhamadhav
akhra pond and 18 taxa from Mandir dighi pond. 9 taxa were found
common in both the ponds. In Radhamadhav akhra pond classical relationship
of dissolved oxygen and free carbon dioxide was established
with low dissolved oxygen and high free carbon dioxide concentration.
Pearson correlation coefficient analysis showed that the number of taxon
was highly correlated with the density of taxon in both the ponds. Canonical
correspondence analysis revealed that for Radhamadhav akhra pond,
eigen values were 0.784 for axis 1 and 0.630 for axis 2 while for Mandir
dighi pond eigen values were 0.825 for axis 1 and 0.740 for axis 2. Taxonenvironment
correlation showed that aquatic insect community and environmental
variables were highly correlated in both the ponds. Shannon
diversity index of Radhamadhav akhra pond was in the range of 1.5−1.7
and Mandir dighi pond was in the range of 1.9−2.0. According to the dominance
status by Engelmann’s Scale, only Rhagovelia sp. was found Eudominant
in Radhamadhav akhra pond. No eudominant taxon was found
in Mandir dighi pond.

- by Arpita Dalal
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- Freshwater Ecology

We evaluated the influence of environmental integrity and the potential as bioindicator of larval stages of species of Trichoptera in 20 streams of first to fourth order in the Pindaı´ba river basin, Mato Grosso, Central Brazil. We measured stream integrity with the habitat integrity index (HII), establishing three levels of conservation: preserved, altered and impacted environments. We used (i) simple regression to assess the effect of habitat integrity on species abundance of Trichoptera and (ii) the indicator species analysis (IndVal) to assess the potential as bioindicator of each species. We found that 12 morphospecies showed relationship with HII: six species were bioindicators of preserved and two species of altered environments. Morphospecies that showed relationship in the two analyses (i and ii) were considered strong bioindicators, considering that the other species supported higher environmental variation, becoming evident that loss of physical structure reduces the abundance of organisms specialized in preserved environments. The results showed that the distribution and abundance of trichopterans can be an indicator of habitat integrity. Trichopteran species have bioindicator potential, corroborating the hypotheses of this work that abundance
of organisms will be smaller in environments with low integrity, and that many species are specific to preserved environments, disappearing from impacted environments, and also characteristic species of altered environments.

- by Leandro Juen
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- Entomology, Herpetology, Aquatic Ecology, Conservation Biology

Italian Edition of T.M. Smith, R.L. Smith Elements of Ecology. Sixth edition. M. Pearson Paravia Bruno Mondadori S.p.A. 706 pp. [editing and translation of chapters 1, 2, 3, 4, 5, 6, 7, 16, 17, 18, 19]

- by Marco Cantonati
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- Ecology, Freshwater Ecology, Textbook

Papua dikenal sebagai pulau yang alamnya relatif belum banyak dijamah manusia. Pulau ini menjadi rumah bagi banyak fauna termasuk ikan. Salah satu ikan yang hidup di sini adalah ikan pelangi arfak dan dalam beberapa literatur berbahasa Inggris dikenal sebagai arfak rainbowfish. Di daerah asalnya, yaitu di sekitar daerah Prafi, ikan ini disebut “Anggicak” dalam Bahasa Suku Arfak (Hatam) dan di daerah Kebar dikenal sebagai “Wadjen”. Berdasarkan hasil penelusuran dalam daftar merah IUCN (The International Union for Conservation of Nature) semenjak tahun 1996 sampai dengan tahun 2018, status konservasi ikan ini sudah termasuk dalam kategori rawan punah (vulnerable).

- by Emmanuel Manangkalangi and +1
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- Aquatic Ecology, Conservation Biology, Freshwater Biology, Freshwater Ecology

The biodiversity value of Northern European temporary ponds has been little recognised, and there are many gaps in our understanding of their ecology. This study investigated the wetland (including aquatic) plant and macroinvertebrate assemblages, and the physico-chemical characteristics of 71 temporary ponds in semi-natural habitats. Temporary ponds supported on average 17 (SD ± 8) wetland plant and 25 (SD ± 10) macroinvertebrate species. Over 75% of temporary ponds supported at least one uncommon (local, nationally scarce or Red Data Book) species. The number of uncommon wetland plant species and total number of macroinvertebrate species were both positively correlated with the total number of wetland plant species (richness), but there was no correlation between the number of uncommon and common macroinvertebrate species. Almost three-quarters of temporary ponds supported at least one nationally scarce macroinvertebrate and 8% supported at least one nationally scarce plant across a wide range of physico-chemical characteristics. The main environmental factor influencing the composition of temporary pond communities was water chemistry, particularly pH and alkalinity. The occurrence of facultative as well as obligate temporary pond species suggested that this habitat may play an important role in the interchange of species between waterbodies at the landscape scale.

- by Martin J Hodson
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- Ecology, Freshwater Ecology

Elasmobranch teeth from freshwater facies are common in many microvertebrate assemblages in the Upper Cretaceous of western North America. Research on the essentially complete Upper Cretaceous terrestrial microvertebrate record of southern Utah has resulted in the collection of specimens from many stratigraphic horizons not sampled elsewhere. Two genera of hybodont shark and two clades of primitive (rhinobatoid and sclerorhynchoid) ray are present throughout the sequence. Orectoloboid sharks fi rst appear in freshwater facies in the Coniacian, and two orectoloboid shark genera are present in the Campanian. Two new genera, Cristomylus and Pseudomyledaphus, are identifi ed as part of a rapidly evolving line of myledaphine rhinobatoid rays; they include the new species Cristomylus nelsoni, Cristomylus bulldogensis, Cristomylus cifellii, and Pseudomyledaphus madseni. Additionally, the sclerorhynchoid saw fi sh Texatrygon brycensis and Columbusia deblieuxi and the orectoloboid shark Cantioscyllium markaguntensis are described.

- by James Kirkland
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- Biostratigraphy, Freshwater Ecology, Fossil Elasmobranchii, Mass extinctions
- by Maria Gabriela Cuezzo
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- Freshwater Ecology
- by Bram Vanschoenwinkel
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- Limnology, Freshwater Ecology, Salinisation

Managing fisheries through rapid environmental change requires diverse approaches for identifying and adapting to novel ecological conditions. For the Wisconsin Ceded Territory, we calculated 473 adult walleye (Sander vitreus) production (P), biomass (B), and P/B estimates for 1990-2012. Frequency distributions for production statistics were right-skewed, indicating the fishery is generally dominated by low production populations. Mean P, B, and P/B were significantly elevated in natural recruitment (NR) lakes compared with combination (NR + stocking) and stocked-only lakes. Furthermore, combination populations had significantly higher production compared with stocked-only lakes. In NR lakes, walleye productivity changed little over time; however, the proportion of NR populations has declined over time. In combination and stocked-only populations, there were significant temporal declines in P, B, and P/B, and the proportion of these lakes has increased through time. This study reveals the crucial link between fish recruitment potential and fish production, helping to explain why the regional walleye fishery is struggling. Causes for walleye recruitment and production declines remain unclear, but long-term shifts in fish habitats are likely involved (e.g., from climate change and indirect food web effects). Decreasing walleye production is an important and emerging fishery management challenge in the region and portends a need to adapt fisheries management systems collaboratively for future sustainability. Résumé : La gestion des ressources halieutiques dans un contexte de changements environnementaux rapides requiert des approches variées pour cerner les nouvelles conditions écologiques et s'y adapter. Pour le Wisconsin Ceded Territory, nous avons calculé 473 estimations de la production (P), de la biomasse (B) et du rapport P/B de dorés jaunes (Sander vitreus) adultes pour la période de 1990 à 2012. Les distributions de fréquences des statistiques sur la production étaient asymétriques vers la droite, indiquant que des populations de faible production sont généralement dominantes dans cette pêche. Les valeurs moyennes de P, B et P/B étaient significativement élevées dans les lacs à recrutement naturel (RN) par rapport aux lacs à recrutement combiné (RN + empoissonnement) et aux lacs à empoissonnement seulement. En outre, les populations de lacs à recrutement combiné avaient une production significativement plus élevée que celles des lacs à empoissonnement seulement. Dans les lacs RN, la productivité des dorés jaunes a peu varié dans le temps, alors que la proportion de populations de lacs RN a diminué. Dans les populations de lacs à recrutement combiné et de lacs à empoissonnement seulement, il y a eu des baisses significatives dans le temps des valeurs de P, B et P/B, et la proportion de ces lacs a augmenté au fil du temps. L'étude fait ressortir le lien crucial entre le potentiel de recrutement de poissons et la production de poissons, contribuant à expliquer pourquoi la pêche régionale au doré jaune est en difficulté. Les causes des baisses du recrutement et de la production de dorés jaunes demeurent incertaines, mais des changements à long terme des habitats des poissons y participent vraisemblablement (p. ex. découlant des change-ments climatiques et d'effets indirects sur les réseaux trophiques). La baisse de la production de dorés jaunes constitue un important nouveau défi pour la gestion de cette ressource dans la région et souligne la nécessité d'une approche collaborative pour adapter les systèmes de gestion afin d'assurer la pérennité de cette pêche. [Traduit par la Rédaction]

- by Daisuke Goto
- •
- Ecosystems Ecology, Limnology, Fisheries Science, Fisheries

Conservation of endangered British crayfish (Austropotamobius pallipes) involves translocation to isolated waterbodies (Ark Sites) and reintroductions from hatchery stock. The species is restricted in the wild to relatively alkaline waterbodies. The optimum pH conditions that maximise growth and survival are unknown. This information would benefit the selection of Ark Sites and hatchery water chemistry. Here we measure growth and survival of juvenile A. pallipes in the laboratory using three pH levels from within the species’ natural range. Survival at pH 8.6 was high (94%), whereas that at lower pH levels was low (pH 6.5, 25%; pH 7.1, 34%). Growth (moult increment and frequency) was also higher at pH 8.6. Survival was also lower for Thelohania contejeani-infected animals, with a trend towards higher mortality in infected individuals at lower pH. Electron microscopy revealed a lower cuticle thickness at pH 6.5 than higher pH which was associated with an apparent increase in the number of endocuticle layers. We therefore recommend that high pH (ca. 8.6) be used as a target for Ark Site selection and hatchery water chemistry in order to maximise survival and growth.

- by Neal R Haddaway
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- Crayfish Ecology, Freshwater Ecology, Water Chemistry, Crustacea Decapoda

The assemblage of the plankton in freshwater system has significant impact on the productivity of the lake. This study assessed the community characteristics of the phytoplankton and zooplankton in Laguna de Bay and their possible association. Chlorophyceae that includes species Surirella angusta (AR=0.163), Biddulphia hyalina (AR=0.527), and Pediastrum duplex meyen (AR=0.018) dominated the whole plankton community. It is followed by Copepods (AR=0.267) which represents zooplankton community. Shannon diversity index (H’ = 1.779) implied that the over-all diversity of the plankton community is highly represented by the total species in the study area. An environment impact assessment on the lake is recommended to ascertain the extent of the anthropogenic effects on the lake trophic state.

- by Ryan V . Labana
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- Freshwater Biology, Freshwater Ecology, Plankton ecology
- by Jianguang Qin
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- Ecology, Freshwater Ecology, Freshwater
- by Melanie Goral
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- Wind Energy, Freshwater Ecology, Wind history and literature

Saber A.A., El-Tablawy N.H., El-Refaey A.A., Saber H., Singh P., Janse van Vuuren S., Cantonati M. 2022. Cyanoprokaryotes and algae: Classification and habitats. Chapter 1 In: Handbook of Algal Biofuels, M. El-sheekh & A. Abomohra (Eds).... more

- by Marco Cantonati
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- Limnology, Cyanobacteria, Freshwater Ecology, Freshwater Benthic algae