Academic literature on the topic 'Veliger larvae'
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Journal articles on the topic "Veliger larvae"
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Mills, Edward L., Connie Adams, Robert O'Gorman, Randall W. Owens, and Edward F. Roseman. "Planktivory by alewife (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) on microcrustacean zooplankton and dreissenid (Bivalvia: Dreissenidae) veligers in southern Lake Ontario." Canadian Journal of Fisheries and Aquatic Sciences 52, no. 5 (May 1, 1995): 925–35. http://dx.doi.org/10.1139/f95-092.
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The objective of this study was to describe the diet of young-of-the-year and adult alewife (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) in nearshore waters coincident with the colonization of Lake Ontario by Dreissena. Laboratory experiments and field observations indicated that alewife and rainbow smelt consumed dreissenid veligers and that the veligers remained intact and identifiable in the digestive tract for several hours. Dreissenid larvae were found in field-caught alewife and rainbow smelt in August 1992, even though veliger densities were low (<0.1/L). Zooplankton dominated the diet of all fish and veliger larvae were <0.1% of the biomass of prey eaten by these fish. Density of veligers and the distribution of settled dreissenids declined from west to east along the south shore of Lake Ontario. Based on veliger consumption rates we measured and the abundance of veligers and planktivores, we conclude that planktivory by alewife and smelt in the nearshore waters of Lake Ontario did not substantially reduce the number of veligers during 1991–1993. However, our results indicate that if the density of veligers in Lake Ontario decreases, and if planktivores remain abundant, planktivory on veliger populations could be significant.
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Miller, A. Whitman, Amanda Reynolds, Mark S. Minton, and Rachel Smith. "Evidence for stage-based larval vulnerability and resilience to acidification in Crassostrea virginica." Journal of Molluscan Studies 86, no. 4 (September 8, 2020): 342–51. http://dx.doi.org/10.1093/mollus/eyaa022.
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ABSTRACT Using image analysis of scanning electron micrographs (SEMs), we compared differences in growth of D-stage veligers [i.e. prodissoconch I and II (PI and PII) larvae] of eastern oysters Crassostrea virginica grown in mesohaline water under high- and low-CO2 conditions. We found SEMs to reveal no evidence of dissolution or shell structure deformity for larval shells in either of the CO2 treatments but detected prominent growth lines in the PII regions of larval shells. The number of growth lines closely approximated the duration of the experiment, suggesting that growth lines are generated daily. Mean growth line interval widths were 20% greater for larval shells cultured in low- vs high-CO2 conditions. Crassostrea virginica veliger larvae were shown to tolerate high CO2 levels and aragonite saturation states (Ωarag) < 1.0, but larval growth was slowed substantially under these conditions. Differences in growth line interval width translate into substantial changes in shell area and account for previously observed differences in total shell area between the treatments, as determined by light microscopy and image analysis. Other studies have documented high mortality and malformation of D-stage larvae in bivalves when pre-veliger life stages (i.e. eggs, gastrula and trochophores) were exposed to elevated CO2. Our experiments revealed statistical differences in rates of larval survival, settlement and subsequent early-stage spat mortality for veligers reared in high- and low-CO2 conditions. Although each of these rates was measurably affected by high CO2, the magnitude of these differences was small (range across categories = 0.7–6.3%) suggesting that the impacts may not be catastrophic, as implied by several previous studies. We believe the apparent disparity among experimental results may be best explained by differential vulnerability of pre-veliger stage larvae and veligers, whereby PI and PII larvae have greater physiological capacity to withstand environmental conditions that may be thermodynamically unfavourable to calcification (i.e. Ωarag < 1.0).
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Lalita, Jans D. "UNIQUENESS OF LARVAL RELEASING OF Littoraria Scabra L. (GASTROPODA: LITTORINIDAE), IN TOMBARIRI MANGROVE, NORTH SULAWESI,INDONESIA." JURNAL ILMIAH PLATAX 6, no. 2 (July 26, 2018): 1. http://dx.doi.org/10.35800/jip.6.2.2018.20574.
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This research was found novelty of reproduction strategy uniqueness of L. scabra that very rare in nature, reverse male function fertilized eggs are sucked for brooding in mantle of male up to hatching as veligers, and thus, the males are capable of releasing the larvae in full and new moon at spring tide during the research. The second finding in reproduction strategy uniqueness of L. scabra that mating individuals, both males and females, released their larvae during research period. Key Words : Littoraria scabra, uniqueness, releasing, veliger, male and female ABSTRAKPenelitian yang amat langka di alam ini menemukan kebaharuan keunikan strategi reproduksi Littoraria. scabra, di waktu kopulasi jantan berperan seks terbalik menyedot sebagian telur yang dibuahi dan dierami telur-telur yang dibuahi dalam tubuhnya sampai menetas menjadi larva-larva serta melepaskan larva-larva tersebut di bulan penuh dan baru yang mengikuti siklus pasang selama penelitian. Temuan amat langka kedua keunikan strategi reproduksi L. scabra, yang amat langka di alam dengan pasangan jantan-betina lagi kawin melepaskan larva-larva baik jantan maupun betina pada siklus bi-lunar bersamaan dengan siklus pasang selama penelitian. Kata Kunci : Littoraria scabra, keunikan,pelepasan, veliger, jantan dan betina
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Mulyana, Jeane Siswitasari, Achmad Farajallah, and Yusli Wardiatno. "Redescription of Larval Development in Cultured Pearl Oyster Pinctada maxima." ILMU KELAUTAN: Indonesian Journal of Marine Sciences 23, no. 2 (June 21, 2018): 109. http://dx.doi.org/10.14710/ik.ijms.23.2.109-112.
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Larval development plays a major role in efficient pearl culture. The cultured larvae will be later used for recipient and donor oysters in cultured pearl production. Larval developmental stage of silver lip pearl oyster Pinctada maxima has been reported by several studies. Those studies used female and male oyster parents directly taken from natural habitat.This study aimed to redescribe larval development of P. maxima from commercial pearl oyster culture farm in Indonesia. Larval development of this species whose parents are originated from selected groups in the pearl culture farm has not been reported yet, thus it is necessary to be described. This species undergoes specific larval developmental stage. The larvae were observed under microscope, and then the average shell length (SL) and shell height (SH) were measured. D-shaped veliger larva (77.4±0.3 µm SL; 65.4±1.1 µm SH) appeared 20 h after fertilization. Tenday-old larva (156.2±2.8 µm SL; 149.5±5.6 µm SH) had developed umbo region so it was called umbonal larva. Umbonal larva then developed further into plantigrade larva (411.3±9.8 µm SL; 380.5±6.9 µm SH) in 25 days after fertilization. Developmental stage and larval sizein P. maxima is similar with those observed in P. fucata and P. margaritifera. Keywords: growth, larva, plantigrade, shell, umbo, veliger
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Goddard, Jeffrey H. R. "Palio dubia (Nudibranchia: Doridina) from the north-west Atlantic Ocean: is its morphology at hatching consistent with settlement one day later?" Journal of the Marine Biological Association of the United Kingdom 91, no. 8 (April 16, 2010): 1651–54. http://dx.doi.org/10.1017/s002531541000010x.
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Hamel et al. (2008) reported that veliger larvae of the nudibranch gastropod Palio dubia settled 1 to 3 days after hatching and that metamorphosis commenced shortly thereafter. This is an anomalously short larval period for a nudibranch described as having planktotrophic development. I examined the embryonic development and hatching larvae of P. dubia collected intertidally from Maine, USA. Veliger larvae with shells 120 μm long and lacking eyespots and propodia developed in 7 days at 20°C from eggs averaging 69 μm in diameter. Their size and morphology were typical of planktotrophic nudibranchs known to have minimum larval periods of weeks to months, and the available evidence does not suggest any other mode of development exists in P. dubia. The larval period of P. dubia is likely an order of magnitude longer than reported by Hamel et al. (2008).
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Pirkova, A. V., and L. V. Ladygina. "Meiosis, embryonic, and larval development of the Black Sea scallop Flexopecten glaber ponticus (Bucquoy, Dautzenberg & Dollfus, 1889) (Bivalvia, Pectinidae)." Marine Biological Journal 2, no. 4 (December 29, 2017): 50–57. http://dx.doi.org/10.21072/mbj.2017.02.4.05.
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The bivalve Flexopecten glaber ponticus is an endemic and extinguishing species of the Black Sea listed in Red book of Crimea. The sequence of meiosis stages following fertilization; embryonic and larval development of F. glaber ponticus were studied. The bivalve reproduces in June and July; these mollusks are simultaneous hermaphrodites. When spawning stimulated, fertilization of mature ova 54.7 ± 2.11 mkm in diameter take place at the first metaphase stage of meiosis. There were 12 bivalents with the sizes from 1.59 to 4.54 mkm on the metaphase plate. The duration of meiosis stage, embryonic and larvae development were determined. The structure of veliger provinculum was described. Right and left lock-valves consist of 4 teeth: two of them are on the front and back side on each valve. Measurements of larvae are presented. The description of shell and lock morphology will enable identification of F. glaber ponticus larvae at planktonic veliger stage. The data on duration of meiosis stage, embryonic and larvae development can be used in developing biotechnics of bivalve reproduction.
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Hamzah, Aris Sando, Kukuh Nirmala, Eddy Supriyono, and Irzal Effendi. "The performance of gold-mouth turban Turbo chrysostomus larvae in different temperature and salinity media." Jurnal Akuakultur Indonesia 20, no. 1 (February 10, 2021): 14–23. http://dx.doi.org/10.19027/jai.20.1.14-23.
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Suhu dan salinitas merupakan parameter kualitas air yang berperan penting terhadap proses fisiologis siput mata bulan (T. chrysostomus) sehingga berdampak terhadap perkembangan, pertumbuhan dan kelangsungan hidup larva. Tujuan dari penelitian ini yaitu untuk mengevaluasi pengaruh suhu dan salinitas terhadap perkembangan, pertumbuhan dan kelangsungan hidup larva siput mata bulan (T. chrysostomus). Stadia pre-torsion veliger dicapai sekitar 11 jam 36 menit setelah fertilisasi atau sekitar 3 jam setelah trocophor. Stadia post-torsion veliger awal ditandai dengan cangkang yang telah terbentuk sempurna dan pada post-torsion veliger akhir, larva sudah mengembangkan operkulum, kaki, dan propodium. Hasil pengamatan menunjukan bahwa perlakuan A1B3 memberikan waktu pencapaian stadia post-torsion veliger awal dan post-torsion veliger akhir tercepat yaitu masing-masing 19 jam 36 menit dan 22 jam 36 menit setelah pembuahan. Sedangkan perlakuan A1B1 memberikan waktu pencapaian stadia post-torsion veliger awal dan post-torsion veliger akhir terlama yaitu masing-masing 20 jam 30 menit dan 23 jam 25 menit setelah pembuahan. Suhu tidak berpengaruh nyata sedangkan salinitas berpengaruh nyata terhadap laju pertumbuhan harian larva siput mata bulan. Laju pertumbuhan harian tertinggi pada suhu 27±0.5oC (A1) tercatat pada perlakuan B3 dan menunjukan nilai yang tidak berbeda nyata dengan perlakuan B2. Suhu dan salinitas memberikan pengaruh yang signifikan namun interaksi keduanya tidak menunjukan pengaruh yang signifikan terhadap tingkat kelangsungan hidup larva siput mata bulan. Perlakuan A1B3 memberikan persentase tingkat kelangsungan hidup tertinggi dan tidak menunjukan nilai yang berbeda nyata dengan perlakuan A1B2. Parameter kualitas air yang diperoleh masih mendukung performa larva siput mata bulan hingga mencapai stadia juvenil.
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Fatoni, Muhammad, Delianis Pringgenies, and Ali Djunaedi. "Study on the Development of Spiral babylonia snail Tiger Snail Juvenil Eggs (Babylonia spirata Linnaeus, 1758) in the Laboratory." Jurnal Moluska Indonesia 4, no. 1 (April 1, 2020): 27–37. http://dx.doi.org/10.54115/jmi.v4i1.22.
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Several marine gastropods are known to have high economic value, one of which is the Spiral babylonia snail. They commonly exploited for meat, shell, or operculum. Tiger snail meat is commonly exported and consumed by fishermen. Its shell is used as a material for industrial lime and for omamen. Operculum is commonly used as a medicinal and perfume ingredient). However, the recent production has decreased due to the limited information of seasonal catch. One way to overcome these obstacles is through culture activities. The provision of seeds is an important link in the culture system, therefore the study of the spawning process and larval development is an important requirement for the development of larval rearing techniques. This study aims to determine the development process of juvenil eggs and the survival rate of tiger snails reared in the laboratory.. The study was conducted at the Laboratory of Marine Farm Subdivision in Kudus, Pt Pura Bahari, Jepara Regency. This sudy used experimental method with descriptive data analysis. Adult tiger snails were caught from Bunga waters, Demak. The snails were reared in a rectangular tube filled with 15 cm filtered sea water and 5 cm of sand. Egg capsules were reared in a 4 liters circular tube with continuous aeration. The hatched larvae were reared in a 300 liters circular tube filled with filtered seawater, continuously aerated and fed with Chlorella plankton . Our result showed that tiger snails spawn naturally and produce egg capsules. The incubation period for the capsule is 6 days, then develop into veliger larva for 12 days. The veliger larvae metamorphosed,and become juvenil. The lowest survival rate observed in the veliger stage. The survival rate of the egg and the intracapsular trochopore stages were quite high (tube I = 98.413%; tube II = 98.238%; tube III = 90.476%), then the lowest was in the veliger stage (tube I = 3,468%; tube II = 2.603%; tube III = 2,598%) and the juvenil stage is quite high compared to the previous phase (tube I = 3,413%; tube II = 2,479%; tube III = 2,351%).
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Coelho, M. R., S. Fuentes, and M. J. Bebianno. "TBT effects on the larvae of Ruditapes decussatus." Journal of the Marine Biological Association of the United Kingdom 81, no. 2 (April 2001): 259–65. http://dx.doi.org/10.1017/s0025315401003721.
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The effects of sublethal tributyltin (TBT) concentrations on the growth and development of Ruditapesdecussatus larvae were studied. Veliger larvae of R. decussatus were exposed to TBT nominal concentrations of 25, 50, 75 and 100 ng Sn l−1 in the water for a period up to 13 d. Larval growth and development were chosen as endpoints for evaluation of TBT toxicity. Growth of R. decussatus larvae was severely affected by TBT concentrations (25–100 ng Sn l−1). A 3- to 6-fold reduction growth was observed in these early larval stages. Furthermore, R. decussatus larvae exposed to TBT did not develop further than D-larvae while the unexposed ones reached the umbonated stage.
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Claxton, W. Trevor, and Elizabeth G. Boulding. "A new molecular technique for identifying field collections of zebra mussel (Dreissena polymorpha) and quagga mussel (Dreissena bugensis) veliger larvae applied to eastern Lake Erie, Lake Ontario, and Lake Simcoe." Canadian Journal of Zoology 76, no. 1 (January 1, 1998): 194–98. http://dx.doi.org/10.1139/z97-175.
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The veliger larvae of two introduced species of bivalves, the zebra mussel (Dreissena polymorpha) and the quagga mussel (Dreissena bugensis), are difficult or impossible to tell apart morphologically. We have developed specific dreissenid polymerase chain reaction (PCR) primers from dreissenid bivalve DNA sequences, which amplify a region of the cytochrome c oxidase subunit I mitochondrial gene. Non-dreissenid mtDNA, as found in field-collected veliger samples, was not amplified by these new PCR primers. The DNA sequence of this region distinguishes zebra mussel from quagga mussel larvae. Restriction digests of this region using the enzyme ScrFI showed no intraspecies variation in restriction pattern. We used this technique to distinguish the species of veliger larvae collected in eastern Lake Erie, Lake Ontario, and Lake Simcoe. In our limited study, no quagga mussel larvae were found in Lake Simcoe, suggesting that this mussel species has not yet spread to the Kawartha Lake system. No zebra mussel larvae were found in either Lake Erie or Lake Ontario. These preliminary results add to the growing evidence that the quagga mussel is replacing the zebra mussel in parts of the lower Great Lakes.
Dissertations / Theses on the topic "Veliger larvae"
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Fuchs, Heidi L. "Biophysical coupling between turbulence, veliger behavior, and larval supply." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/39193.
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Thesis (Ph. D.)--Joint Program in Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 2005.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references.
The goals of this thesis were to quantify the behavior of gastropod larvae (mud snails Ilyanassa obsoleta) in turbulence, and to investigate how that behavior affects larval supply in a turbulent coastal inlet. Gastropod larvae retract their velums and sink rapidly in strong turbulence. Turbulence-induced sinking would be an adaptive behavior if it resulted in increased larval supply and enhanced settlement in suitable coastal habitats. In laboratory experiments, mud snail larvae were found to have three behavioral modes: swimming, hovering, and sinking. The proportion of sinking larvae increased exponentially with the turbulence dissipation rate over a range comparable to turbulence in a tidal inlet, and the mean larval vertical velocity shifted from upward to downward in turbulence resembling energetic nearshore areas. The larval response to turbulence was incorporated in a vertical advection-diffusion model to characterize the effects of this behavior on larval supply and settlement in a tidal channel. Compared to passive larvae, larvae that sink in turbulence have higher near-bed concentrations throughout flood and ebb tides.
(cont.) This high larval supply enables behaving larvae to settle more successfully than passive larvae in strong currents characteristic of turbulent tidal inlets. A study was conducted at Barnstable Harbor, MA to estimate the responses of larvae to turbulence in the field. Gastropod larvae from different coastal environments had genus-specific responses to turbulence, suggesting that larvae use turbulence for large-scale habitat selection. On ebb tides, mud snail larvae had a similar response to turbulence as in the laboratory, with greater sinking velocities in strong turbulence. Behavior estimates differed for flood and ebb tides, indicating that additional physical cues influence behavior. Turbulence-induced sinking behavior would enhance retention and promote settlement of mud snail larvae in habitats like Barnstable Harbor.
by Heidi L. Fuchs.
Ph.D.
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Valley, Jenna. "Phenotyptic Plasticity in Larval and Juvenile Marine Invertebrates: Effects of Predators, Food, Gravity, and Sunlight." Thesis, University of Oregon, 2016. http://hdl.handle.net/1794/20714.
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Phenotypic plasticity, the ability of a single genotype to be expressed as a range of phenotypes in response to environmental variation, is a widespread phenomenon. Documented increasingly among the larval stages of marine organisms, phenotypic plasticity in the veliger larvae of the marine snail Littorina scutulata was investigated in response to predatory, nutritional, and gravitational stimuli.
Veligers developed rounder shells, smaller apertures, and reinforced aperture margins in response to water-borne cues from predatory crab larvae. The nature and degree of the induced-morphologies depended on cue composition and conferred decreased vulnerability to predation.
Food-limited veligers developed larger feeding and swimming structures (vela) with longer cilia relative to shell size compared to larvae raised with high food. This inducible offense corresponded with a decrease in vertical swimming speed, an unexpected result possibly reflecting behavioral manipulation of individual velar components. A cell proliferation assay indicated that growth of the larger structure was achieved partially by a steady rate of cell division over a longer period of time; an initially higher level of cell proliferation in veligers raised on high food dropped off sharply.
Velar lobe asymmetry, where one lobe is larger than the other, may exist to offset an asymmetry in weight distribution due to how the larval shell is carried. The larger velar
lobe overlies the protruding spire of the larval shell. Bi- and multi-lobed vela get bigger with shell size but follow different rules with regards to the relationship between velar asymmetry and shell asymmetry. Experimental alternations of mass distribution of the larval shell caused changes in the ratio of area between each side of the velum and total velar growth for larvae of L. scutulata.
Following settlement and metamorphosis, juveniles of intertidal marine invertebrates are subject to additional stressors that can manifest as phenotypic variation. Color differences between juvenile and adult Strongylocentrotus purpuratus were shown to be caused by variation in light exposure. Green juveniles raised in sunlight turned purple (due to more pigment) and showed decreased susceptibility to artificial UVR than urchins kept in the dark, which remained green (due to less pigment).
This dissertation includes previously unpublished co-authored material.
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Foschini, Anna. "Effetto dei farmaci ambientali propranololo e carbamazepina sullo sviluppo larvale del mitilo, Mytilus galloprovincialis." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/9880/.
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La presenza dei farmaci in ambiente sta assumendo sempre più rilevanza come problematica da affrontare e a cui tentare di porre rimedio. Anche se le concentrazioni nei corpi idrici risultano piuttosto basse (μg/L o ng/L), i farmaci hanno proprietà diverse dagli inquinanti convenzionali e possono ugualmente indurre effetti dannosi nella fauna acquatica.
In questo lavoro sono stati valutati gli effetti del propranololo (PROP, farmaco β-bloccante) e della carbamazepina (CBZ, farmaco anticonvulsivante), su di uno stadio larvale del mitilo Mytilus galloprovincialis (larva veliger – 48 ore post fecondazione).
L’esposizione a concentrazioni crescenti dei due farmaci induce un progressivo aumento della anormalità delle larve, che mostrano malformazioni o ritardi nello sviluppo. Sia PROP che CBZ aumentano l’attività dei trasportatori implicati nella Multixenobiotic Resistance (MXR), indicando che il sistema di estrusione degli xenobiotici viene attivato già in questa fase dello sviluppo larvale. Analogamente, PROP aumenta l’espressione dei geni che codificano per le proteine della famiglia MXR, P-gp ed MRP. Aumenta anche l’espressione dei geni che codificano per catalasi e GST, suggerendo un aumento delle risposte antiossidanti/detossificanti. PROP aumenta i trascritti dell’anidrasi carbonica, mentre al contrario riduce i trascritti per la proteina extrapalliale: non è chiaro quindi l’effetto del farmaco sulla regolazione della espressione di proteine coinvolte nella formazione della conchiglia. CBZ aumenta l’espressione dei trascritti per P-gp ma diminuisce quella relativa ad MRP. Inoltre, riduce l’espressione dei geni codificanti per catalasi e GST, e della proteina extrapalliale, senza avere effetto sui trascritti dell’anidrasi carbonica. In generale possiamo dire che i due farmaci inducono evidenti alterazioni a livello biochimico e molecolare che possono influenzare sia la detossificazione che la biomineralizzazione, con conseguenze rilevanti per lo sviluppo larvale.
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Brentano, Adriana Maria. "Controle de larvas de Limnoperna fortunei coletadas em ambiente natural com o uso de agente oxidante clorado." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/129521.
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Limnoperna fortunei (Dunker, 1875), conhecido como mexilhão-dourado é um molusco bivalve invasor de origem asiática. Foi introduzido em 1991, no Rio da Prata em Buenos Aires, chegando assim nas águas da América do Sul, provavelmente através da água de lastro. Foi observado pela primeira vez no Brasil, em dois locais distintos, na área do Delta do Jacuí, em Porto Alegre, Rio Grande do Sul e em Corumbá, Mato Grosso do Sul, no ano de 1998. Essa espécie invasora vem causando significativos impactos ambientais e prejuízos econômicos para as indústrias que utilizam água bruta para resfriamento, pois entopem as tubulações pela formação de aglomerados (macrofouling), que vão obstruindo o fluxo contínuo da água. Para minimizar os danos causados pelas espécies invasoras, são recomendados diversas formas de controle, estes podem ser físicos, químicos e biológicos. Neste trabalho, para os testes de controle utilizamos a forma química, e o agente químico controlador, o hipoclorito de sódio. Conforme descrito em bibliografia, alguns estudos comprovam que os indivíduos adultos são mais resistentes a agentes químicos, nesse sentido, demonstrou ser mais vantajoso utilizar as larvas como alvo de controle, para que elas não se fixem nas tubulações, evitando a formação e aumento dos macrofouling. Esse trabalho objetivou adaptar um método de controle de larvas do mexilhão-dourado (Limonperna fortunei) com a utilização de hipoclorito de sódio, testando uma concentração baixa e eficaz na mortalidade das larvas. Os experimentos foram realizados em laboratório, onde larvas de mexilhão-dourado foram expostas por cinco minutos em solução de hipoclorito de sódio e avaliadas em tempos pós-exposição de 1 hora, 6 horas, 12 horas e 24 horas. Para avaliar o percentual de mortalidade foi utilizado o método de Análise de Variância (ANOVA) e para verificar quais concentrações são estatisticamente diferentes ao nível de significância de 5% foi feito o teste de Tukey. Os resultados obtidos no sistema estudado com aplicação do agente clorado, demonstraram que mesmo quando em baixos teores de cloro livre e com tempo de exposição de cinco minutos, se mostrou eficiente no controle das larvas do mexilhão-dourado. A exposição de uma solução de 0,001mg.L-1 de cloro livre, a mortalidade das larvas avaliadas atingiu 100% em 24 horas. As concentrações de Cloro Livre testadas atendem a Resolução CONAMA 357 de 2005 para uma condição de qualidade Classe I de águas doces e a Portaria 2914 do Ministério da Saúde que estabelece a qualidade da água para consumo humano.Limnoperna fortunei (Dunker, 1875), known as the golden mussel is from Asia and was probably introduced in 1991, in the La Plate river in Buenos Aires, thus reaching the waters of South America via ballast water. Was first observed in Brazil in area of the Delta Jacuí, in Porto Alegre, Rio Grande do Sul and in Corumbá, Mato Grosso do Sul, in 1998. This invasive species has caused significant environmental impacts and huge losses for industries that use raw water for cooling because they form clumps that clog pipes (macrofouling), blocking the stream of water. To minimize the damage caused by invasive species, various forms of control, which can be physical, chemical and biological agents are used. In this work, to do the control tests, we used as chemical form the agent sodium hypochlorite. As described in some studies, adults mussels are more resistant to chemical agents, this sense proved to be more advantageous to use the larvae as target, preventing them from attaching the pipes and form the macrofoulings. This study aimed to adapt a method of controlling larvae of the golden mussel (Limonperna fortunei) with the use of sodium hypochlorite, and verifying a low and effective concentration on larval mortality. The experiments were performed in the laboratory, where golden mussel larvae were exposed for five minutes in a solution of sodium hypochlorite and evaluated in post-exposure times of 1 hour, 6 hours, 12 hours and 24 hours. To evaluate the percentage of mortality was used the method of analysis of variance (ANOVA) and to see which concentrations are statistically different at a significance level of 5% was done the Tukey test. The system studied with application of chlorinated agent, even at low levels of free chlorine and exposure time of five minutes, proved effective in controlling larvae of the golden mussel, because even with the exposure of a solution of 0.001 mg. L-1 of free chlorine, the mortality of larvae reached 100% in 24 hours. The concentrations of free chlorine tested attend CONAMA Resolution 357 of 2005, to a condition of quality Class I of freshwater and 2914 Ordinance of the Ministry of Health, establishing water quality for human consumption.
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Churchill, Christopher J. "Population Dynamics of Zebra Mussels (Dreissena Polymorpha) in a North Texas Reservoir: Implications for Invasions in the Southern United States." Thesis, University of North Texas, 2013. https://digital.library.unt.edu/ark:/67531/metadc407755/.
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This dissertation has two main objectives: first, quantify the effects of environmental conditions on spatio-temporal spawning and larval dynamics of zebra mussels (Dreissena polymorpha [Pallas 1771]) in Lake Texoma, and second, quantify the effects of environmental conditions on survival, growth, and reproduction of young of the year (YOY) juvenile zebra mussels. These biological responses directly influence population establishment success and invasive spread dynamics. Reproductive output of the zebra mussel population in Lake Texoma was significantly related to water temperature and lake elevation. Annual maximum larval (veliger) density decreased significantly indicating a population crash, which was likely caused by thermal stress and variability of lake elevation. In 2011, temperatures peaked at 34.3°C and lake elevation decreased to the lowest level recorded during the previous 18 years, which desiccated a substantial number of settled mussels in littoral zones. Estimated mean date of first spawn in Lake Texoma was observed approximately 1.5 months earlier than in Lake Erie, and peak veliger densities were observed two months earlier. Veligers were observed in the deepest oxygenated water after lake stratification. During a 69-day in situ experiment during summer in Lake Texoma, age-specific mortality of zebra mussels was generally high until temperatures decreased to approximately 28°C, which was observed after lake turnover in late summer. No study organism died after temperatures decreased to less than 26°C, which indicates individuals that survive high summer temperatures are likely to persist into autumn/winter. Shell length growth and soft tissue growth rates were related to temperature and chlorophyll-a concentration, respectively. Growth rates of study organisms were among the highest ever reported for D. polymorpha. Water temperature and body size influenced reproduction of YOY zebra mussels in Lake Texoma. Fecundity of females were positively related to temperature; however, sperm production was negatively related to temperature, which indicates males could be more sensitive to physiologically-stressful conditions than females and could perform better in cooler waters. YOY mussels spawned up to approximately 40,000 eggs and 3.47E+08 sperm after a single-summer growing season. Reproductive effort and reproductive mass were independent of sex. YOY individuals from each study site (n = 5) were able to spawn viable gametes capable of sperm binding and egg cleavage, which provides the first evidence that YOY zebra mussels can successfully reproduce. Individual mortality of zebra mussels will likely be high in warm waters and intermittent, extreme droughts, which are observed more frequently at lower latitudes, can significantly reduce population sizes. However, rapid growth and single-season maturation can decrease generation times and could facilitate establishment and spread of zebra mussels in warm-water environments in the southern United States.
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Fujdiak, Radek. "Analýza a optimalizace datové komunikace pro telemetrické systémy v energetice." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-358408.
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Telemetry system, Optimisation, Sensoric networks, Smart Grid, Internet of Things, Sensors, Information security, Cryptography, Cryptography algorithms, Cryptosystem, Confidentiality, Integrity, Authentication, Data freshness, Non-Repudiation.
Books on the topic "Veliger larvae"
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Hopkins, Gordon J. The zebra mussel, dreissena polymorpha: A photographic guide to the identification of microscopic veligers. [Toronto, Ont: Environment Ontario], 1990.
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Slovenia) International Centre of Graphic Arts (Ljubljana. Velike!: Dela iz zbirke Mednarodnega grafičnega likovnega centra. Edited by Coldwell Paul author and Škrjanec, Breda, author, editor of compilation. Ljubljana: Mednarodni grafični likovni center, 2012.
Find full textBook chapters on the topic "Veliger larvae"
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Uthe, Daniela. "Fine structure of the cephalic sensory organ in veliger larvae of Littorina littorea, (L.) (Mesogastropoda, Littorinidae)." In Advances in Littorinid Biology, 45–52. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0435-7_5.
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"Early Life History of Fishes in the San Francisco Estuary and Watershed." In Early Life History of Fishes in the San Francisco Estuary and Watershed, edited by Stephen M. Bollens and Alison M. Sanders. American Fisheries Society, 2004. http://dx.doi.org/10.47886/9781888569599.ch2.
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<em>Abstract.</em>—Pacific herring <em>Clupea pallasi </em>is a commercially and ecologically important fish with a sizable stock that spawns and spends its early life history in the San Francisco Estuary (SFE). Yet very little is known about the basic ecology of larval Pacific herring in the SFE. We undertook a 3-year field study (1999–2002), focused on winter and spring collections in two regions of the SFE (the Central and San Pablo bays), to address three objectives: (1) determine seasonal abundance patterns of larval Pacific herring in the two bays, (2) examine the diet of larval Pacific herring, and (3) evaluate the condition of larval Pacific herring in the two bays. Pacific herring were a conspicuous component of the winter larval fish assemblage in both the San Pablo and Central bays, comprising a maximum of 22.5% and 5.5% of total abundance, respectively. Larval Pacific herring abundance peaked in February or March of each year, reaching a maximum density of 2.53/m<sup>3 </sup>(San Pablo) and 0.52/m<sup>3 </sup>(Central Bay). Length frequency distributions suggested that at least 2–3 cohorts were produced each year, with some evidence that larvae were slightly larger in San Pablo Bay. Larval Pacific herring fed on a broad range of prey types, including tintinnids, copepodids, copepod nauplii, diatoms, and gastropod veligers. The unusually high proportion of tintinnids in the diet (87% by number in March 2001) suggests an important protozoan–metazoan linkage. Condition of larvae was assessed by analyses of covariance of a “growth sensitive” variable (i.e., body weight, anal body depth, or pectoral body depth) regressed against a “growth insensitive” variable (i.e., standard length). These results showed marked differences between the bays: in Central Bay, early (small) larvae exhibited better condition, but within San Pablo Bay, larvae exhibited a greater rate of improved condition with increasing age (size). This suggests the possibility of important differences in the Central and San Pablo bays as larval Pacific herring nursery grounds. Several areas of future research on the ecology of larval Pacific herring in SFE are recommended (e.g., coupling between horizontal and vertical distributions and advective flow fields, predation, and feeding dynamics on protozoan versus metazoan prey).
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Šoštarić, Renata, and Tihana Vilović. "Plant Macro-Remains and Traces of Leaves from Virje and Hlebine." In Interdisciplinary Research into Iron Metallurgy along the Drava River in Croatia, 212–26. Archaeopress Archaeology, 2021. http://dx.doi.org/10.32028/9781803271026-10.
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During years of archaeological research of mediaeval settlements and Late Antique and mediaeval smelting workshops in the area of Podravina, archaeobotanical samples were collected from the following sites: Hlebine – Dedanovice (H-Ded), Hlebine – Velike Hlebine (H-VH), Virje – Volarski breg (V-VB), and Virje – Sušine (V-Suš). They include fruits, seeds, and leaf imprints/remains. Despite the relatively large number of samples, only a small number of finds was found. It mostly consisted of non-carbonized plant remains from various species of weed and ruderal plants, that most likely represent recent contamination. Of the few carbonized finds, the most significant are the remains of cereals preserved in a rather poor condition: proso millet (Panicum miliaceum), foxtail millet (Setaria italica), spelt (Triticum spelta) and naked wheat (Triticum aestivum group), and fragmented and damaged remains of large-grain cereals (Cerealia). Due to the small number of archaeobotanical finds originating from the archaeological formations dated into the wide period from the Late Iron Age to the Early Modern Age, nothing can be said in more detail about the diet, agriculture, or other activities of the population of Virje and Hlebine during individual archaeological and historical periods. In general, it can be concluded, taking into account other sites from the area of Podravina (Torčec and Virovitica Kiškorija jug), that different types of cereals, such as wheat/spelt (Triticum), barley (Hordeum vulgare) and proso millet (Panicum miliaceum), formed the basis of the daily diet of the population of Podravina throughout various investigated periods, probably in combination with legumes, and that they were grown in the vicinity of the settlement. Finds of grapevine (Vitis vinifera) suggest that wine also had a significant place in the past of Podravina. At the position of Virje – Sušine, in Trench S-7, SU 314, a smelting furnace hearth wall fragment with a leaf imprint was found. The imprint most probably belongs to black alder (Alnus glutinosa) and dates from the period of Late Antiquity (late 4th/early 5th century). At the position of Hlebine – Velike Hlebine, in Trench S-2, SU 102, a partially fossilized leaf was found in the slag from the period of the transition from Late Antiquity to the Early Middle Ages. Since the sample was too small, it could not be identified with certainty.