Response of the riverine fish community to the construction and operation of a diversion hydropower plant in central Chile     

Evelyn Habit  Mark C. Belk  Oscar Parra 《水产资源保护:海洋与淡水生态系统》2007,17(1):37-49

• 1. Chilean rivers have a large potential for hydropower development, and they also contain a unique native fish fauna with a high level of endemism. Several diversion hydropower plants have recently been constructed in Chile; however, the response of fish communities to these new hydropower plant designs is not well known.
• 2. Responses of native and non‐native fish to the construction and operation of a new hydropower plant that diverts water from two rivers were quantified. The Laja River is highly regulated and manipulated with three older (40 yr) dam‐based hydropower plants and irrigation diversions located upstream from the new facility. In contrast, the Rucúe River has no other hydropower facilities and is comparatively undisturbed.
• 3. Prior to construction, the Laja River had a fish community with lower species richness compared with the Rucúe River. The fish community structure in the Laja River was dramatically altered after the new hydropower facility began operation. On the other hand, in the Rucúe River, even though abundance of fish declined, there was less of a change in the total fish community structure. The fish community in the Rucúe River exhibited greater resistance to change compared with the Laja River.
• 4. The species most affected were the introduced salmonids and an endangered native species Percilia irwini.
• 5. Although diversion hydropower designs may have less impact than traditional dam‐based hydropower facilities, results of this study indicate that diversion hydropower structures can cause large changes in the fish community.

Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Overview of Fish Growth Hormone Family. New Insights in Genomic Organization and Heterogeneity of Growth Hormone Receptors     

J. Pérez-Sánchez  J.A. Calduch-Giner  M. Mingarro  S. Vega-Rubín de Celis  P. Gómez-Requeni  A. Saera-Vila  A. Astola  M.M. Valdivia 《Fish physiology and biochemistry》2002,27(3-4):243-258

Growth hormone (GH), prolactin (PRL) and somatolactin (SL) are single chain proteins structurally and functionally related. Fish PRL and GH receptors (PRLR, GHR) have been characterized in several fish species. There is limited evidence of fish PRLR isoforms, but emerging data support the existence of different GHR variants. In gilthead sea bream, black sea bream, turbot and fugu, but not in zebrafish, GHR has retained an exclusive fish intron (10/10A). In gilthead sea bream and turbot, this intron is not alternatively spliced, but the black sea bream intron is either removed or retained during mRNA processing, resulting in a long GHR isoform with a 31 amino acid insertion that does not alter the open reading frame. This or any other GHR variant are not found in gilthead sea bream, but a truncated anchored form has been reported in turbot. The latter GHR isoform comprises extracellular and trans-membrane domains, the first 28 amino acids of the intracellular domain and 21 divergent amino acids before a stop codon. This GHR variant is the result of alternative splicing, being the 3′ UTR and the divergent sequence identical to the sequence of the 5′ end of the 9/10 intron. The physiological significance of different fish GHR isoforms remains unclear, but emerging data provide suitable evidence for season and nutrition related changes in the somatototropic axis activity. The up-regulation of circulating GH together with the decrease of plasma titres of insulin-like growth factor-I (IGF-I), an altered pattern of serum IGF binding proteins and a reduced expression of hepatic IGF-I and GHRs represent a mechanism conserved through vertebrate evolution. It secures the preferential utilization of mobilized substrates to maintain energy homeostasis rather than tissue growth. Somatolactin also changes as a function of season, ration size, dietary amino acid profile and dietary protein source creating opposite plasma GH and SL profiles. There is now direct evidence for a lipolytic effect of fish SL, acting at the same time as an inhibitory factor of voluntary food intake. Indeed, long-term feeding restriction results in the enlargement of the summer GH peak, whereas the SL rise coincident with shortened day length is delayed in juvenile fish until late autumn. These findings agree with the idea that SL may act as a marker of energy surplus, priming some particular process such as puberty onset. However, it remains unclear whether SL works through specific receptors and/or dimers or heterodimers of GH and PRL receptors.  相似文献   

Demography of southern Australian bottlenose dolphins living in a protected inverse estuary          下载免费PDF全文

Cecilia Passadore  Luciana Möller  Fernando Diaz‐Aguirre  Guido J. Parra 《水产资源保护:海洋与淡水生态系统》2017,27(6):1186-1197

A clay‐based formulation of the herbicide imazaquin containing exclusively the biologically active enantiomer     

Rocío Lpez‐Cabeza  Thomas Poiger  Juan Cornejo  Rafael Celis 《Pest management science》2019,75(7):1894-1901

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Long term responses of olive trees to salinity     

J.C. Melgar  Y. Mohamed  P.A. García-Galavís  M.A. Parra  R. Fernández-Escobar 《Agricultural Water Management》2009,96(7):1105-1113

Water demand for irrigation is increasing in olive orchards due to enhanced yields and profits. Because olive trees are considered moderately tolerant to salinity, irrigation water with salt concentrations that can be harmful for many of fruit tree crops is often used without considering the possible negative effects on olive tree growth and yield. We studied salt effects in mature olive trees in a long term field experiment (1998-2006). Eighteen-year-old olive trees (Olea europaea L.) cv. Picual were cultivated under drip irrigation with saline water composed of a mixture of NaCl and CaCl₂. Three irrigation regimes (i. no irrigation; ii. water application considering soil water reserves, short irrigation; iii. water application without considering soil water reserves and adding a 20% more as a leaching fraction, long irrigation) and three salt concentrations (0.5, 5 or 10 dS m⁻¹) were applied. Treatments were the result of the combination of three salt concentrations with two irrigation regimes, plus the non-irrigated treatment. Growth parameters, leaf and fruit nutrition, yield, oil content and fruit characteristics were annually studied. Annual leaf nutrient analyses indicate that all nutrients were within the adequate levels. After 8 years of treatment, salinity did not affect any growth measurement and leaf Na⁺ and Cl⁻ concentration were always below the toxicity threshold of 0.2 and 0.5%, respectively. Annual and accumulated yield, fruit size and pulp:stone ratio were also not affected by salts. However, oil content increased linearly with salinity, in most of the years studied. Soil salinity measurements showed that there was no accumulation of salts in the upper 30 cm of the soil (where most of the roots are present) because of leaching by rainfall at the end of the irrigation period. Results suggest that a proper management of saline water, supplying Ca²⁺ to the irrigation water, using drip irrigation until winter rest and seasonal rainfall typical of the Mediterranean climate leach the salts from the first 0-60 cm depth, and growing a tolerant cultivar, can allow using high saline irrigation water (up to 10 dS m⁻¹) for a long time without affecting growth and yield in olive trees.  相似文献   

Advances in the culture of the Mexican bullseye puffer fish Sphoeroides annulatus, Jenyns (1842)     

María Cristina Chávez Sánchez  Luis Álvarez-Lajonchère  María Isabel Abdo de la Parra  & Noemí García Aguilar 《Aquaculture Research》2008,39(7):718-730

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Partial replacement of fish meal by porcine meat meal in practical diets for Pacific white shrimp (Litopenaeus vannamei)     

Crisantema Hernndez  Miguel A. Olvera-Novoa  Karla Aguilar-Vejar  Blanca Gonzlez-Rodríguez  Isabel Abdo de la Parra 《Aquaculture (Amsterdam, Netherlands)》2008,277(3-4):244-250

In this study, it evaluated the growth performance of the Pacific white shrimp Litopenaeus vannamei in response to the replacement of fish meal with rendered porcine meat meal (PMM) in its diet. Six isolipidic and isonitrogenous diets were formulated with 0, 25, 35, 45, 55 or 65% replacement of fish meal with PMM on a protein basis. Shrimp grew from 0.55 g to > 3.6 g during the 41-day experimental period. Specific growth rate (SGR) was significantly lower when PMM inclusion was 26.18% or greater, replacing more than 45% fish meal protein. A significant negative relationship was observed between growth response and the level of fish meal protein replacement with PMM protein. Methionine content decreased as PMM inclusion levels increased, consequently compromising growth performance. Dry feed intake (DFI) and the feed conversion ratio (FCR) were unaffected by fish meal replacement levels. The protein efficiency ratio (PER) was highest at the lowest PMM inclusion level. Apparent protein digestibility coefficient (APDC) for PPM was 66.2%. Experimental diets D-0 and D-25 had apparent dry matter digestibility (ADMDs) ranging from 77–81% and ADPs from 82–85%, while the diets with higher PMM inclusion (D-35 to D-65) had a significantly lower ADMD range (70–72%) and APD range (73–78%). It is concluded that porcine meat meal is an acceptable alternative animal protein source that can replace up to 35% of fish meal protein in shrimp diets without significant adverse effects on growth, survival, FCR, PER and body composition.  相似文献   

Analysis of genetic variability in <Emphasis Type="Italic">Couepia</Emphasis> accessions using AFLP markers     

Yomara Rozo  Lorena Quintero  Mauricio Parra  Carlos Rodríguez  Luz Marina Melgarejo 《Genetic Resources and Crop Evolution》2009,56(1):77-83

Couepia is a genus distributed in tropical regions of America. The nut of some Couepia species is used as fresh fruit and oil source for local communities. Despite its critical situation of conservation and its economic potential, there is a lack of information on the genetic variability of Couepia species. This study examines AFLP variation among 40 accessions of Couepia collected in the Colombian Amazonian region, representing two species: Couepia dolichopoda and Couepia subcordata. The individuals were examined for 96 markers generated from four EcoRI/MseI primer pairs, with 80% polymorphism across all accessions studied. According to cluster analysis, 40 accessions were grouped into two major clusters, corresponding to the two species analyzed, except one case whose situation is discussed. In C. dolichopoda accessions, significant correlation between the clustering pattern and the geographical origin was detected; the extent of variation within and among its collect sites was examined by AMOVA. The knowledge about the genetic variability of the accessions examined contributes to development of Couepia conservational efforts.  相似文献   

Effect of processing on the phytochemical profiles and antioxidant activity of corn for production of masa, tortillas, and tortilla chips   总被引：2，自引：0，他引：2  

de la Parra C  Saldivar SO  Liu RH 《Journal of agricultural and food chemistry》2007,55(10):4177-4183

The phytochemical profiles (total phenolics, anthocyanins, ferulic acid, carotenoids) and antioxidant activities of five types of corn (white, yellow, high carotenoid, blue, and red) processed into masa, tortillas, and tortilla chips were studied. The nixtamalization process significantly (p < 0.05) reduced total phenolics and antioxidant activities when compared to raw grains. Nixtamalized grains exhibited higher concentration of free phenolics and soluble conjugated ferulic acid and had lower concentrations of bound phenolics and ferulic acid than unprocessed grains. Among processed products, there was little difference in the phytochemical contents and antioxidant activities. Among types of corn, the highest concentrations of total phenolics, ferulic acid, and antioxidant activity were observed in the high-carotenoid genotype followed by the regular yellow counterpart. The white corn contained the lowest amount of total phenolics and antioxidant activity. The pigmented blue corn had the highest anthocyanin concentration followed by the red counterpart. These findings suggest that lime-cooking significantly reduced the phytochemical content of nixtamalized products but released phenolics and ferulic acid.  相似文献   

Soil calcium and pH monitoring sensor system     

Lemos SG  Nogueira AR  Torre-Neto A  Parra A  Alonso J 《Journal of agricultural and food chemistry》2007,55(12):4658-4663

An agrarian sensorial system based on temperature, moisture, and all solid-state ion-selective potentiometric sensors was developed with the objective of monitoring the behavior of H+ and Ca2+ ions in soil and in real conditions, contributing with a new tool that tries to complement the current precision agriculture technology. The evaluation of the sensorial system to pH monitoring presented a good correlation between the results obtained by the system and the standard methodology, allowing us to notice the soil buffer capacity at different soil depths. With regard to calcium, the sensor system also presented an agreement between its results and those obtained by flame atomic absorption spectrometry, using a calibration model based on multiple linear regressions that allows the correct determination of Ca2+ concentrations in soil depths where the relative moisture is different. In this way, using well-known potentiometric sensors in a complex, discontinued, and heterogeneous matrix, such as soil, the sensorial system proved to be a useful task for agrochemical field applications.  相似文献