Long-term monitoring of potamodromous migratory fish larvae in an undammed river

2020 ◽  
Vol 71 (3) ◽  
pp. 384 ◽  
Author(s):  
Rafael Rogério Rosa ◽  
Jislaine Cristina Silva ◽  
Andréa Bialetzki
Keyword(s):  
Fish Larvae ◽  
Larval Density ◽  
Temporal Distribution ◽  
Larval Survival ◽  
Local Conditions ◽  
Key Species ◽  
Survival And Growth ◽  
Term Monitoring ◽  
Salminus Brasiliensis

Freshwater fish reproduce annually in environments that provide favourable conditions for spawning and larval survival and growth. Thus, the aims of this study were to use long-term larval density data to evaluate the temporal distribution of the dourado Salminus brasiliensis, its habitat use for larval development and the effects of environmental variables on reproduction. S. brasiliensis larvae were mainly recorded in October and January in the Ivinheima River, and higher densities of larvae, primarily in the preflexion and flexion stages, were captured in the river and backwater biotopes. Water level, dissolved oxygen and temperature were the primary variables affecting the density of larvae, and this species can migrate over 200km to reproduce in the Ivinheima River and its tributaries. Therefore, S. brasiliensis is reproducing annually, indicating favourable local conditions for migration and spawning, and exhibits differential use of biotopes for reproduction, including rivers and backwaters (spawning) and lagoons (refuge and growth). Therefore, considering that the dourado is a key species for conservation, ensuring its reproductive success means maintaining a balanced ecological structure.

scholarly journals The Observatorio Astronómico Nacional - Tonantzintla: Site Evaluation

2009 ◽  
Vol 5 (S260) ◽  
Author(s):  
H.M. Hernández-Toledo ◽  
L.A. Martínez-Vázquez ◽  
A. Pani-Cielo
Keyword(s):  
Ccd Photometry ◽  
Local Conditions ◽  
Astronomy Education ◽  
Site Evaluation ◽  
New Instrumentation ◽  
Sky Conditions ◽  
Alternative Solutions ◽  
Term Monitoring

AbstractThe objective of this contribution is to present some results of an evaluation on the local conditions at the site that were considered in order to propose that the Observatorio Astronómico Nacional, Tonantzintla, (OAN-Tonantzintla) become a National Facility for Astronomy Education. The evaluation included a quantitative diagnostic (CCD photometry) on the quality of the local sky. The attributes of the 1-m telescope, the current instrumentation and a well planned upgrading that includes new instrumentation is considered at the basis for a successful transition maintaining the attractiveness of the site for astronomy education. A 3-year upgrading program actually in progress at UNAM is providing funding for that purpose. Physics and astronomy programs at college and graduated levels at UNAM will benefit from this, yielding clear connections among astronomy researchers and educators and students at various levels. Although the OAN-Tonantzintla faces the danger of deteriorating its sky conditions, we are maintaining awareness of the night sky characteristics in long-term monitoring campaigns and encouraging the local authorities to find alternative solutions to this problem.

scholarly journals DISTRIBUCIÓN Y DENSIDAD DE ICTIOPLANCTON EN EL ESTUARIO DE BAHÍA MÁLAGA, PACÍFICO COLOMBIANO (SEPTIEMBRE DE 2009-FEBRERO DE 2010)

2016 ◽  
Vol 43 (1) ◽  
Author(s):  
Diana Medina Contreras ◽  
Jaime Cantera ◽  
Eugenia Escarria ◽  
Luz M Mejía Ladino
Keyword(s):  
Fish Assemblages ◽  
Larval Fish ◽  
Fish Larvae ◽  
Larval Density ◽  
Temporal Distribution ◽  
Mesh Size ◽  
Temporal Variations ◽  
Taxonomic Composition ◽  
Total Density ◽  
The Relationship

The density, taxonomic composition, and spatial and temporal distribution of the estuarine ichthyoplankton of Bahía Málaga (Pacific coast of Colombia) are described, as well as the relationship between biological parameters and some physicochemical variables. Samples were collected at 12 stations along the principal navigation canal; these samples were taken in four areas following the design of Barletta-Bergan. Surface sweeps were carried out with a conical-cylindrical net (mesh size 500 µm, mouth diameter 0.6 m, length 3.5 m). Salinity and temperature were measured before each sweep. A total of 69019 larvae/1000 m³, representing 23 families, 36 genera and 40 species were collected during monthly sampling from September, 2009 to February, 2010. Carangidae (39.0%) was the most abundant family, followed by Sciaenidae (27.1%) and Engraulidae (20.1%). The most frequent families were Sciaenidae (26.6%), followed by Carangidae (22.8%) and Engraulidae (14.7%) which are important families in larval fish assemblages in tropical estuaries. Eighty percent of total density was provided by six species, of which Seriola morphotype 1 (Carangidae) and Cetengraulis mysticetus (Engraulidae) were the most abundant and dominant. No correlation was found between density and salinity (Spearman, R = 0.23) or temperature (Spearman, R = 0.51). Analysis of spatial and temporal variations of larval density shows significant differences among the months sampled (Anova, p = 0.0029; p < 0.05), but not among areas (Anova, p = 0.078), suggesting that Bahía Málaga offers adequate conditions for the presence of fish larvae.

КОМПЛЕКСНА ОЦІНКА ДИНАМІКИ ЧИСЕЛЬНОСТІ УГРУПОВАНЬ КОЛОНІАЛЬНИХ НАВКОЛОВОДНИХ ПТАХІВ (НА ПРИКЛАДІ ДЕЯКИХ ОСТРОВІВ СИВАШУ)

2011 ◽  
Vol 1 (3) ◽  
pp. 85
Author(s):  
О. V. Matsyura
Keyword(s):  
Population Dynamics ◽  
Bird Species ◽  
Breeding Birds ◽  
Extinction Rate ◽  
Breeding Bird ◽  
Key Species ◽  
Number Dynamics ◽  
Long Term Monitoring ◽  
Term Monitoring

<p>The problem of the mathematical analysis of the number dynamics of the nesting waterbirds for the islands of the south of Ukraine is examined. The algorithm of the evaluation of changes in the number of island birds is proposed. Data of the long-term monitoring of the number of birds were analyzed according to this algorithm. The necessity of the implementation of the statistical indices together with the graphic representation of island birds’ turnover is proved. The trends of population dynamics are determined for the key species. The discussed procedure of the complex evaluation is proposed for the management planning of the island bird species and their habitats.</p> <p>The performed analysis of the number dynamics of the key-stone breeding island birds showed that, with the exception of little tern, the population status and the prognosis of number are sufficiently favorable.  From the data of long-term monitoring we came up with the conclusion about the existence of island habitats with carrying capacity to maintain the additional number of breeding birds. In the case of unfavorable conditions like strengthening of anthropogenic press, concurrent interrelations, deficiency of feed resources or drastic reduction of breeding biotopes, the birds due to turnover are capable to successfully react even without reducing their number and breeding success. The extinction rate of the breeding bird species from the island sites directly correlates with the number of breeding species. For the species with equal abundance, the extinction probability is higher for birds, whose numbers are unstable and characterized by significant fluctuations. This testifies the urgency of the constant monitoring and analysis of the number dynamics of breeding bird species in region.</p> <p>The suggested procedure of analysis is recommended for drawing up of management plans and performing of prognoses of number of breeding island bird species. More detail analysis with use of quantitative data on breeding birds will be the next step of the study of the island birds’ turnover. The results of the analysis of population dynamics assist to count the minimal population size for the colonization of new islands and stable existence of bird communities.  Detailed analysis will allow to estimate the effect of competition on population and to determine the competitive variability inside and between the species breeding on islands.</p> <p><em>Key words: Ukraine, colonial waterbirds, islands, dynamics of number, analysis</em></p> <p> </p>

scholarly journals No place like home? A test of the natal habitat-biased dispersal hypothesis in Scandinavian wolves

2018 ◽  
Vol 5 (12) ◽  
pp. 181379 ◽  
Author(s):  
Ana Sanz-Pérez ◽  
Andrés Ordiz ◽  
Håkan Sand ◽  
Jon E. Swenson ◽  
Petter Wabakken ◽  
...  
Keyword(s):  
Canis Lupus ◽  
Methodological Approach ◽  
Distribution Patterns ◽  
Habitat Characteristics ◽  
Habitat Types ◽  
Local Conditions ◽  
Natal Habitat ◽  
Dispersal Distances ◽  
Term Monitoring

Natal dispersal is an important mechanism for the viability of populations. The influence of local conditions or experience gained in the natal habitat could improve fitness if dispersing individuals settle in an area with similar habitat characteristics. This process, defined as ‘natal habitat-biased dispersal’ (NHBD), has been used to explain distribution patterns in large carnivores, but actual studies evaluating it are rare. We tested whether grey wolf Canis lupus territory establishment was influenced by the habitat characteristics of the natal territory using the long-term monitoring of the Scandinavian wolf population. We paired the locations of natal and established territories, accounted for available habitats along the dispersing route, and compared their habitat characteristics for 271 wolves during 1998–2012. Wolves with the shortest dispersal distances established in natal-like habitat types more than expected by chance, whereas wolves that dispersed longer distances did not show NHBD. The pattern was consistent for male and female wolves, with females showing more NHBD than males. Chances to detect NHBD increased with the size of habitat defined as available. This highlights the importance of considering the biological characteristics of the studied species when defining habitat availability. Our methodological approach can prove useful to inform conservation and management to identify habitats to be selected by reintroduced or naturally expanding populations.

scholarly journals Plankton in waters adjacent to the Laje de Santos state marine conservation park, Brazil: spatio-temporal distribution surveys

2017 ◽  
Vol 65 (4) ◽  
pp. 564-575 ◽  
Author(s):  
Marília Bueno ◽  
Samantha Fernandes Alberto ◽  
Renan de Carvalho ◽  
Tânia Marcia Costa ◽  
Áurea Maria Ciotti ◽  
...  
Keyword(s):  
Temporal Distribution ◽  
Taxonomic Composition ◽  
Marine Conservation ◽  
Zooplankton Biomass ◽  
Adjacent Area ◽  
Coastal Marine ◽  
Spatio Temporal ◽  
Term Monitoring

Abstract The coastal marine plankton plays a major role in ecosystem functioning by linking pelagic and benthonic environments through energy fluxes. Understanding the dynamic of planktonic organisms is also crucial for conservation and management purposes. Plankton was sampled at ten sites in the waters of the PEMLS and the adjacent area, on four different occasions through 2013 and 2015 in order to identify key planktonic groups and protocols for long-term monitoring. Ninety taxa of zooplanktonic organisms were found with holoplanktonic copepods and cladocerans dominating samples. Zooplankton biomass, mortality and taxonomic composition varied both in space and time. Surface chlorophyll-a concentrations varied spatio-temporally. A protocol for monitoring the plankton of the waters in and adjacent to the PEMLS is suggested based on biomass and mortality of zooplankton and biomass of phytoplankton using periodically in situ calibrated ocean color satellite imagery.

scholarly journals Spatial and temporal distribution of fish larvae in marginal lagoons of Pantanal, Mato Grosso State, Brazil

2010 ◽  
Vol 8 (1) ◽  
pp. 123-134 ◽  
Author(s):  
Karina Keyla Tondato ◽  
Lúcia Aparecida de Fátima Mateus ◽  
Simoni Ramalho Ziober
Keyword(s):  
Fish Larvae ◽  
Abiotic Factors ◽  
Larval Density ◽  
Temporal Distribution ◽  
Water Transparency ◽  
Spatial And Temporal Distribution ◽  
Mato Grosso ◽  
Zooplankton Density ◽  
Depth Water ◽  
Distribution Of Fish

An analysis was made of the spatial and temporal distribution of the abundance and composition of fish larvae assemblies, aiming to ascertain correlations with biotic and abiotic factors in marginal lagoons of the Cuiabá River floodplain in Brazil's Pantanal wetlands. Samples were collected bimonthly in the pelagic region of the marginal lagoons (fourteen lagoons) close to the littoral zone covered by aquatic macrophytes from December 2006 to April 2007. The captured individuals consisted of 2,739 larvae, represented predominantly by Triportheus spp. (Characidae), Parodontidae, Anostomidae, Characidae and Serrasalmidae. Larval density varied among the sample lagoons in December, but the biotic (zooplankton density) and abiotic (water temperature, electrical conductivity, dissolved oxygen, pH, water transparency and lagoon depth) factors did not significantly affect larval composition and abundance. Larvae were captured throughout the sample period, with the highest densities occurring in December and early January. Temporally, lagoon depth, water transparency and fluviometric level showed a negative correlation with larval density. Both the zooplankton and the larval density vary positively, responding likewise to the environmental conditions imposed by flooding. The highest larval density was also found to coincide with the first rains (early December), when the rainfall has not yet reached its peak.

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