scholarly journals Distribución y abundancia espacial y temporal de Stomolophus meleagris (Rhizostomae: Stomolophidae) en un sistema lagunar del sur del Golfo de México

2017 ◽  
Vol 65 (1) ◽  
pp. 167
Author(s):  
Francisco Javier Félix ◽  
Arturo Garrido Mora ◽  
Yessenia Sánchez Alcudia ◽  
Alberto de Jesús Sánchez Martínez ◽  
Andrés Arturo Granados Berber ◽  
...  
Keyword(s):  
Fish Larvae ◽  
Feeding Habits ◽  
Strong Association ◽  
Ecological Impact ◽  
Sustainable Use ◽  
Environmental Parameters ◽  
Important Variable ◽  
Monthly Basis ◽  
Area Unit ◽  
Stomolophus Meleagris

The scyphomedusae feed mainly on microscopic crustaceans, eggs and fish larvae, molluscs and some other jellyfishes. The distribution and abundance of the scyphomedusae has an economic and ecological impact as they are predators that have an influence on the population dynamics of other fisheries. This investigation took place in the lagoon system ‘Arrastradero-Redonda’, Tabasco, from September 2013 to August 2014, with the purpose to provide information on the distribution, and spatial and temporal abundance of Stomolophus meleagris; along with its relation to environmental parameters. A total of 10 stations were defined and biological samples were taken on a monthly basis during this annual cycle. For this purpose, three pulls with a beach seine monofilament (20m long by 3m height, mesh opening 1.5 cm, 5 to 10 minutes) per station were made within a 1 km2 area. Information obtained was used to calculate the fishing efficiency analysis (CPUE con org./Evaluated Area Unit) and to determine the relationship with the environmental parameters. Our results showed that the abundance in the stations 1 to 3 was from 7 to 19 org./km2 from April to August 2014; less organisms were observed in stations 6 to 10 (an average of 1 org./km2) from October 2013 to March 2014. The multiple correlation steps analysis indicated that there is a strong association between the CPUE and some environmental investigated variables, and a 70.9 % variability of the data was observed. The salinity resulted the most important variable because it determined a 64.3 % of variation; it was followed by the temperature with a 3.6 %; meanwhile, dissolved oxygen explained only the 2.9 %, this was mainly because within the area there are several geological, oceanographic and biological factors that favor the distribution of this species due to seawater contribution through the Tupilco bar. With the provided data with this investigation we were able to determine the fishery potential of this resource for Tabasco state. However, additional research is required to allow an extended quantification of this resource, to determine the commercial exploitation areas, and drive studies about reproductive and feeding habits, that may provide the necessary information to establish plans for sustainable use. 

Feeding habits of the bullet tuna Auxis rochei in the southern Tyrrhenian Sea

2007 ◽  
Vol 87 (4) ◽  
pp. 1007-1012 ◽  
Author(s):  
E. Mostarda ◽  
D. Campo ◽  
L. Castriota ◽  
V. Esposito ◽  
M.P. Scarabello ◽  
...  
Keyword(s):  
Diet Composition ◽  
Fish Larvae ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Hierarchical Cluster ◽  
Eastern Coast ◽  
Tyrrhenian Sea ◽  
Monthly Basis ◽  
The North ◽  
Important Prey

A total of 235 bullet tunas (Auxis rochei) was caught off the north-eastern coast of Sicily between March 2003 and March 2004 for the purpose of studying their feeding habits. The fish were caught by means of an experimental surface gill-net during fishing surveys carried out on a monthly basis. The stomach contents were analysed and the prey identified, counted and weighed. The importance of the different prey types was assessed utilizing several feeding indices while possible size-related changes of the diet composition were highlighted by means of hierarchical cluster analysis, nMDS and SIMPER analysis. The results of this study showed that the bullet tuna is an epipelagic off-shore predator feeding on whatever abundant resource is available in the environment with a preference for planktonic crustaceans, small cephalopods and fish larvae. Among crustaceans, hyperiidean amphipods were the most important prey, with Anchylomera blossevillei as the dominant species, followed by the euphausiacean Stylocheiron maximum. Among cephalopods, Heteroteuthis dispar was recorded frequently while fish larvae showed high values of all indices. All prey were pelagic organisms. A size-related change in the diet composition was observed, even if it seemed related to the temporal fluctuations of the zooplanktonic assemblage in the environment. The average prey weight per stomach increased significantly in the larger predators which mostly fed on fish larvae belonging to several commercially important demersal and pelagic species.

scholarly journals Life histories and distribution of ostracods with depth in western Lake Geneva (Petit-Lac), Switzerland: a reconnaissance study

Crustaceana ◽  
2014 ◽  
Vol 87 (8-9) ◽  
pp. 1095-1123 ◽  
Author(s):  
Laurent Decrouy ◽  
Torsten W. Vennemann
Keyword(s):  
Life History ◽  
Water Temperature ◽  
Water Depth ◽  
Organic Matter Content ◽  
Environmental Parameters ◽  
Late Winter ◽  
Lake Geneva ◽  
Monthly Basis ◽  
Sampling Campaign ◽  
Western Lake

Because environmental conditions within a given basin are different for each season and at different water depth, knowledge of the life history and depth distribution of target species is important for environmental and palaeoenvironmental interpretations based on ostracod species assemblages and/or the geochemical compositions of their valves. In order to determine the distribution of species with depth as well as the life history of species from Lake Geneva, a one-year sampling campaign of living ostracods was conducted at five sites (2, 5, 13, 33 and 70 m water depth) on a monthly basis in the Petit-Lac (western basin of Lake Geneva, Switzerland). Based on the results, the different species can be classified into three groups. Littoral taxa are found at 2 and 5 m water depth and include, in decreasing numbers of individuals,Cypridopsis vidua(O. F. Müller, 1776),Pseudocandona compressa(Koch, 1838),Limnocythere inopinata(Baird, 1843),Herpetocypris reptans(Baird, 1835),Potamocypris smaragdina(Vávra, 1891),Potamocypris similis(G. W. Müller, 1912),Plesiocypridopsis newtoni(Brady & Robertson, 1870),Prionocypris zenkeri(Chyzer & Toth, 1858) andIlyocyprissp. Brady & Norman, 1889. Sublittoral species are found in a majority at 13 m water depth and to a lesser extend at 33 m water depth and include, in decreasing numbers of individuals,Fabaeformiscandona caudata(Kaufmann, 1900),Limnocytherina sanctipatricii,Candona candida(O. F. Müller, 1776) andIsocypris beauchampi(Paris, 1920). Profundal species are found equally at 13, 33 and 70 m water depth and includes, in decreasing numbers of individuals,Cytherissa lacustris(Sars, 1863),Candona neglectaSars, 1887 andCypria lacustrisLilljeborg, 1890. The occurrence ofLimnocytherina sanctipatricii(Brady & Robertson, 1869) is restricted from late winter to late spring when temperatures are low, whileC. vidua,L. inopinata,P. smaragdina,P. similis,P. newtoniandIlyocyprissp. occur predominantly from spring to early autumn when temperatures are high. Individuals ofC. neglecta,C. candida,F. caudata,P. compressa,C. lacustris,H. reptansandCp. lacustrisoccur throughout the year with juveniles and adults occurring during the same period (C. neglectaat 70 m,C. lacustrisat 13, 33 and 70 m, andH. reptansat 2, 5 and 13 m water depth) or with juveniles occurring during a different period of the year than adults (C. neglectaat 13 and 33 m andC. candida,F. caudataandP. compressaat their respective depth of occurrence). Among the environmental parameters investigated, an estimate of the relationship between ostracod autoecology and environmental parameters suggests that in the Petit-Lac: (i) water temperature and substrate characteristics are important factors controlling the distribution of species with depth, (ii) water temperature is also important for determining the timing of species development and, hence, its specific life history, and (iii) water oxygen and sedimentary organic matter content is less important compared to the other environmental parameter monitored.

scholarly journals Relación entre el peso freco y el peso seco del rastrojo de maíz en diferentes estados fenológicos del cultivo.

2016 ◽  
Vol 8 (1) ◽  
pp. 20 ◽  
Author(s):  
M. Bänziger ◽  
G. O. Edmeades ◽  
J. Bolaños
Keyword(s):  
Dry Matter ◽  
Dry Weight ◽  
Important Variable ◽  
Growth Stages ◽  
Simple Method ◽  
Plant Parts ◽  
Maturity Period ◽  
Area Unit ◽  
Drying Conditions ◽  
The Relationship

The amount of dry matter produced during various stages of corn growth is a important variable to be taken into consideration. However, the lack of drying facilities makes its measurement a difficult task in the fields. A simple method to convert the fresh weight of a crop in the field into dry weight, could be an answer to that problem. In this study, we calculated the relationship between fresh and dry weight of corn stovers, over several, growth, stages of eight corn cultivars of different vigour and maturity period, at two Mexican locations. The differences between cultivars were for percent stover dry weight (%SDW) most evident in the second half of the grain growth stage, when late cultivars showed less humidity than the early ones. The % SDW was regressed against the phenological developmental stage and expressed as a ratio against antesis (R, days to sampling /days to 50% antesis). The equations (R2 = 0.97 - 0.99) with best results were: Early maturing cultivars: %SDW = 12.6 + 0.94R2 + 1.68R4; Late: %SDW = 16.1 - 4.00 R2 + 3.36R4. There were no consistant differences among cultivars with different vigour levels, even though certain differences were noted among the locations and they were attributed to differences in relative humidity. We describe a protocol for determining the dry weight of corn stover by area unit (t/ha) when drying conditions are not available, by utilizing only a scale and a ruler.We also suggest a method to calculate percent dry matter for a real plant parts (including grain).

Sustainability as a measure of tourism success: the Portuguese Promotional Tourism Boards' view

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jorge Costa ◽  
Mónica Montenegro ◽  
João Gomes
Keyword(s):  
Local Community ◽  
Sustainable Use ◽  
Holistic Approach ◽  
Important Variable ◽  
Content Type ◽  
Local Identities ◽  
Heritage Culture ◽  
Level Of Satisfaction ◽  
Tourism Destinations ◽  
The One

PurposeThe study explores the concept of sustainability as a measure of tourism success from the perspectives of the Portuguese Promotional Tourism Boards.Design/methodology/approachThe study reviews current approaches to defining sustainability and explores how this can contribute to measuring success in tourism destinations using the case of the Portuguese Promotional Tourism Boards to shed light on the theme issue question.FindingsThe evidence that the impacts of tourism are not all beneficial to destinations and their residents is mounting and well addressed by the main world tourism agencies who are now promoting alternative ways for the industry to adopt a more holistic approach to measure the success of tourism destinations. This approach is also being adopted and promoted by some of the world's best tourism destinations.Originality/valueBased on contributions from the Portuguese Regional Promotional Tourism Entities (ERTs), it was possible to define a successful tourism destination as the one that creates income for the local community and ensures the quality of life of the population; values and preserves local identities, heritage, culture and traditions; and promotes the sustainable use of ecosystems and the preservation of natural resources, while practising a circular economy approach. Based on the same source, it was possible to identify the most important variable in evaluating the success of a tourist destination: the level of satisfaction of residents with tourism.

Spectral assessment of organic matter with different composition using reflectance spectroscopy 

2021 ◽  
Author(s):  
Nicolas Francos ◽  
Yaron Ogen ◽  
Eyal Ben-Dor
Keyword(s):  
Organic Matter ◽  
Sustainable Use ◽  
Environmental Parameters ◽  
Least Squares Regression ◽  
Dune Sand ◽  
Spectral Detection ◽  
Soil Surveys ◽  
Different Origins ◽  
Limited Accuracy ◽  
Spectral Assessment

<p>Soil surveys are critical for maintaining sustainable use of natural resources while minimizing harmful impacts to the ecosystem. A key soil attribute for many environmental parameters, such as CO2 budget, soil fertility and sustainability, is soil organic matter (SOM), and its sequestration. Soil spectroscopy is a popular method to assess SOM content rapidly in both field and laboratory domains. However, the SOM source composition differs from soil to soil and the use of spectral-based models for quantifying SOM may present limited accuracy when applying a generic approach for SOM assessment. We therefore examined the extent to which the generic approach can assess SOM contents of different origin using spectral-based models. We created an artificial big dataset composed of pure dune sand as a SOM-free background which was artificially mixed with increasing amounts of different organic matter (OM) sources obtained from commercial compost of different origins. Dune sand has high albedo and yields optimal conditions for SOM detection. This study combined two methods: partial least squares regression for the prediction of SOM content from reflectance values across the 400–2500 nm region, and soil spectral detection limit (SSDL) to judge the prediction accuracy. Spectral-based models to assess SOM content were evaluated with each OM source as well as with a merged dataset that contained all of the generated samples (generic approach). The latter was concluded to have limitations for assessing low amounts of SOM (<0.6%), even under controlled conditions. Moreover, some of the OM sources were more difficult to monitor than others; accordingly, caution is advised when different SOM sources are present in the examined population.</p>

Ichthyoplankton distribution and feeding habits of fish larvae at the inshore zone of northern Patagonia, Chile

2020 ◽  
Vol 50 (4) ◽  
Author(s):  
Ainhoa Bernal ◽  
Leonardo R. Castro ◽  
Samuel Soto ◽  
Luis A. Cubillos
Keyword(s):  
Fish Larvae ◽  
Feeding Habits ◽  
Northern Patagonia

scholarly journals An exposure-effect approach for evaluating ecosystem-wide risks from human activities

2015 ◽  
Vol 72 (3) ◽  
pp. 1105-1115 ◽  
Author(s):  
Antony M. Knights ◽  
Gerjan J. Piet ◽  
Ruud H. Jongbloed ◽  
Jacqueline E. Tamis ◽  
Lydia White ◽  
...  
Keyword(s):  
Human Activities ◽  
Ecological Impact ◽  
Sustainable Use ◽  
Ecosystem Recovery ◽  
Exposure Effect ◽  
Resource Managers ◽  
Recovery Times ◽  
Time Required ◽  
Time Frames

Abstract Ecosystem-based management (EBM) is promoted as the solution for sustainable use. An ecosystem-wide assessment methodology is therefore required. In this paper, we present an approach to assess the risk to ecosystem components from human activities common to marine and coastal ecosystems. We build on: (i) a linkage framework that describes how human activities can impact the ecosystem through pressures, and (ii) a qualitative expert judgement assessment of impact chains describing the exposure and sensitivity of ecological components to those activities. Using case study examples applied at European regional sea scale, we evaluate the risk of an adverse ecological impact from current human activities to a suite of ecological components and, once impacted, the time required for recovery to pre-impact conditions should those activities subside. Grouping impact chains by sectors, pressure type, or ecological components enabled impact risks and recovery times to be identified, supporting resource managers in their efforts to prioritize threats for management, identify most at-risk components, and generate time frames for ecosystem recovery.

scholarly journals Feeding ecology of the crab Munida subrugosa (Decapoda: Anomura: Galatheidae) in the Beagle Channel, Argentina

2004 ◽  
Vol 84 (2) ◽  
pp. 359-365 ◽  
Author(s):  
M. Carolina Romero ◽  
Gustavo A. Lovrich ◽  
Federico Tapella ◽  
Sven Thatje
Keyword(s):  
Organic Matter ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Superficial Layer ◽  
Tierra Del Fuego ◽  
Crab Species ◽  
Monthly Basis ◽  
Beagle Channel ◽  
Food Items ◽  
Autumn And Winter

Munida subrugosa is the most abundant galatheid crab species in the Beagle Channel (55°S 68°W) off Tierra del Fuego, Argentina. Samples of crabs and the epibenthic community were taken on a monthly basis at two different depth strata (<40 m and >70 m), by means of epibenthic trawling from 1998 to 1999. Stomach contents from 1582 crabs were analysed, out of which only 2% had empty stomachs. The quantity of food in the stomach contents was clearly seasonal and similar at both depths. The organic matter varied throughout the year and between both depths, being significantly higher in summer/spring than in autumn/winter. Munida subrugosa shows two different and simultaneous feeding habits: (1) as a predator M. subrugosa feeds on crustaceans, algae, and polychaetes; and (2) as a deposit feeder M. subrugosa consumes particulate organic matter and organisms associated with the superficial layer of the sediment. The composition of the diet of Munida subrugosa was similar for both years, and independent of depth, sex or season. Munida subrugosa selected crustaceans only in autumn and winter, whereas most food items were found according to their availability in the habitat.

scholarly journals Morfología de las piezas bucales y hábitos alimenticios de Leptonema y Smicridea (Trichoptera: Hydropsychidae) del río Gaira, Sierra Nevada de Santa Marta, Colombia

2017 ◽  
Vol 65 (4) ◽  
pp. 1231 ◽  
Author(s):  
Kevin Daniel Alvarez Soraca ◽  
Cesar Enrique Tamaris Turizo ◽  
Cristian José Guzmán Soto
Keyword(s):  
Sierra Nevada ◽  
Nutrient Dynamics ◽  
Dietary Habits ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Head Width ◽  
Morphometric Measurements ◽  
Monthly Basis ◽  
The Difference ◽  
Del Rio

The genera Leptonema and Smicridea belong to the family Hidropsychidae and constitute one of the most important groups in the nutrient dynamics in the tropical aquatic ecosystems, which diversity of microhabitats is exploited by their larvae. However, there is lack of information concerning the detailed and comparative descriptions of mouthparts between these two genera, and their possible relation with their diet. The aim of this paper was to describe the morphology of the mouthparts and the feeding habits of both genera, in the middle basin of the Gaira River (Sierra Nevada de Santa Marta, Colombia). The samples were collected on a monthly basis, with a surber net, between October and December of 2014, and May of 2015. A total of 15 larvae per genus were taken and the Blue Zen Software was used to determine the morphometric measurements of the cephalic pieces. Measurements were taken on photographs obtained from an AxioCam ERc5s camera adapted to a Nikon SMZ 745T stereoscope. To describe the mouthparts a M205A microscope-stereoscope Leica was used. The dietary habits of 15 individuals in total were evaluated by means of the analysis of stomach contents. A discriminant analysis of Hotelling was applied to the morphometric measurements. There were significant differences in head area (HA), head width (HW3), head length (HL2) and left mandible length (LML). In the morphological descriptions were found differences in: head, labrum and submentum. Dietaries profiles were performed to the stomach contents for both genera and the items with highest percentage for Leptonema was MOPG and MOPF with 38 % and 32 %, respectively, and for Smicridea MOPF (38 %) and MOPG (34 %) with significant differences (F = 8.8298, p < 0.05). This study indicated that the evaluated individuals consume a wide variety of resources and the difference of the diet of both genera can be related to the detected morphological differences.

scholarly journals Food and feeding behaviours of Spotfin Swamp Barb Puntius sophore (Hamilton, 1822) of Singhiya River, Biratnagar

Our Nature ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 31-36
Author(s):  
Anjali Risal ◽  
Samjhana Shrestha ◽  
Vinod Kumar Mahaseth
Keyword(s):  
Alimentary Canal ◽  
Feeding Habits ◽  
Gut Content ◽  
Monthly Basis ◽  
Novel Approach ◽  
Food And Feeding ◽  
Gut Length ◽  
Somatic Index ◽  
Local Fisherman ◽  
Puntius Sophore

The present work attempt to present a novel approach about the food and feeding habits of Puntius sophore collected from Singhiya River, Biratnagar. For the study 120 specimens were collected on the monthly basis from March to August 2019, direct from the river with the help of local fisherman. On the basis of percentage of occurrence of gut content analysis the most preferred food item was Green algae (40.6%) followed by diatoms (16.10%), crustaceans (13.50%), protozoan (9.20%), detritus and debris (8.40%), insect larva (7.70%) and rotifers (4.50%). Relative gut length was the lowest at size 4.4-5.1 cm SL and the highest  value at size 9.3-10 cm SL. Gastro somatic index was highest peak at the size of 4.4-5.1 cm SL, which indicate the voracious nature of fish at smaller size. The standard length and body weight show a positively significant with alimentary canal length (r=0.878) and alimentary canal weight (r=0.86.4), respectively. The food and feeding behavior of this fish showed that it is omnivores in nature.

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