共查询到20条相似文献，搜索用时 31 毫秒
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Violeta da Rocha Perini Alessandro Loureiro Paschoalini Cláudia Kelly Fernandes da Cruz Rita de Cássia Gimenes Alcântara de Rocha José Augusto Senhorini Dirceu Marzulo Ribeiro Paulo Sérgio Formagio Nilo Bazzoli Elizete Rizzo 《Fish physiology and biochemistry》2013,39(6):1473-1484
This study investigated for the first time the reproductive biology of Prochilodus lineatus in a system of rivers in southeastern Brasil, relating it to the role of tributary rivers in the reproductive success of this important commercial fish in the Upper Paraná River basin, where a cascade of hydroelectric dams were deployed. Specimens were caught bimonthly in three river sites: (S1) Grande River, downstream from the Porto Colômbia dam; (S2) Pardo River; and (S3) Mogi Guaçu River. Sex steroid plasma levels, fecundity, follicular atresia, oocyte diameter and gonadosomatic index (GSI) were compared among sites. In S1, fish exhibited changes in the reproductive parameters: lower GSI, oocyte diameter and fecundity and higher follicular atresia index, when compared to S2 and S3. Frequency of maturing fish was higher in S3 and spawning was only registered in S3. In sites S2 and S3, plasma concentrations of testosterone and 17β-estradiol in females and testosterone in males showed wide variations following gonadal maturation. Fish from S1 showed few significant variations in sex steroid concentrations throughout the gonadal cycle. These results indicate that P. lineatus does not reproduce in Grande River (S1), but probably uses the Pardo River (S2) as a migratory route towards the Mogi Guaçu River (S3) where they complete gonadal maturation and spawning. Our findings contribute for understanding the reproductive biology of P. lineatus and to highlight the importance of tributaries in impounded rivers as a favourable environment for migration and spawning of fish. 相似文献
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Basin‐scale distribution and haplotype partitioning in different genetic lineages of the Neotropical migratory fish Salminus brasiliensis 
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下载免费PDF全文 Eva C. Rueda Sebastián Sanchez María Cecilia Bruno Jorge Casciotta Gastón Aguilera Adriana E. Almirón Federico J. Ruiz Díaz Delia Fabiana Cancino Baltazar Bugeau Ezequiel Mabragaña Mariano González‐Castro Matías Delpiani Juan Martín Díaz de Astarloa 《水产资源保护:海洋与淡水生态系统》2018,28(2):444-456
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Ismael E. Lozano Sabina Llamazares Vegh María I. Gmez Yanina G. Piazza Javier L. Salva Carlos M. Fuentes 《Fisheries Management and Ecology》2019,26(3):260-268
Prochilodus lineatus (Val.) is one of the main target species of South American freshwater fisheries. The following null hypotheses regarding juvenile recruitment of P. lineatus were tested: (a) recruitment is not determined by variations in larval abundance and (b) recruitment is not determined by variations in discharge. For this purpose, variations in abundance of larvae in main channel drift and monthly captures of juveniles in a floodplain lake of the River Paraná were examined weekly between 2009 and 2016. Mean annual abundances of larval densities and CPUE of juveniles were correlated with a set of hydrometric variables. A positive correlation was found between the abundance of juveniles with high and persistent flood pulses. By contrast, larval abundance was not correlated with juvenile abundance. Pronounced contrast was found in the recruitment of P. lineatus between years of high and low discharge, which supports the hypothesis that floods are the main determining factor for recruitment of this species. 相似文献
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- 1. Costa Rica has recently experienced a rapid proliferation of dams for hydropower on rivers draining its northern Caribbean slope. In the Sarapiquí River Basin, eight hydropower plants were built between 1990 and 1999 and more projects are either under construction or proposed. The majority of these dams are small (<15 m tall) and operate as water diversion projects.
- 2. While the potential environmental effects of individual projects are evaluated prior to dam construction, there is a need for consideration of the basin‐scale ecological consequences of hydropower development. This study was a first attempt to quantify the extent of river fragmentation by dams in the Sarapiquí River Basin.
- 3. Using simple spatial analyses, the length of river upstream from dams and the length of de‐watered reaches downstream from dams was measured. Results indicated that there are currently 306.8 km of river (9.4% of the network) upstream from eight existing dams in the Sarapiquí River Basin and 30.6 km of rivers (0.9% of the network) with significantly reduced flow downstream from dams. Rivers upstream from dams primarily drain two life zones: Premontane Rain Forest (107.9 km) and Lower Montane Rain Forest (168.2 km).
- 4. Simple spatial analyses can be used as a predictive or planning tool for considering the effects of future dams in a basin‐scale context. In the Sarapiquí River Basin, we recommend that future dam projects be constructed on already dammed rivers to minimize additional river fragmentation and to protect remaining riverine connectivity.
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Genetic differentiation and historical demography of wood stork populations in Brazilian wetlands: Implications for the conservation of the species and associated ecosystems 下载免费PDF全文
下载免费PDF全文 Carolina I. Miño Luiza H. da Silva Avelar Fagner M. da Silva Manolo F. Perez Luiza F. Menezes Silvia N. Del Lama 《水产资源保护:海洋与淡水生态系统》2017,27(6):1313-1324
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Reintroduction of a dioecious aquatic macrophyte (Stratiotes aloides L.) regionally extinct in the wild. Interesting answers from genetics 下载免费PDF全文
下载免费PDF全文 Simone Orsenigo Rodolfo Gentili Alfons J. P. Smolders Andrey Efremov Graziano Rossi Nicola M. G. Ardenghi Sandra Citterio Thomas Abeli 《水产资源保护:海洋与淡水生态系统》2017,27(1):10-23
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Jussara Oliveira Vaini Rodrigo Rodrigues Domingues Bruno Lopes da Silva Ferrette Eric M. Hallerman Kenneth Gabriel Mota João Pedro Barreiros Alexandre Wagner Silva Hilsdorf 《水产资源保护:海洋与淡水生态系统》2021,31(8):2119-2130
- The dusky grouper Epinephelus marginatus is a large epinephelid species that occurs in the eastern and south-western Atlantic and western Indian Oceans. Late maturity, protogynous hermaphroditism, site fidelity, and overfishing have all contributed to its demographic decline.
- Connectivity and demography within a broad sampling of dusky grouper populations throughout its distribution were assessed. To do so, genetic variation at 11 polymorphic microsatellite loci and a partial sequence of the mitochondrial control region (mtCR) were evaluated.
- Two major mtCR lineages with a sequence divergence of 1.6% were found. The magnitude of genetic differentiation for mtCR among north and south Atlantic and Indian Ocean populations was high, with ΦST = 0.528.
- DEST and results of discriminant analysis of principal component revealed significant microsatellite genetic differentiation between all collection areas. Significant pairwise DEST showed moderate (0.084) to very great (0.603) differentiation. The effective population size was low for all localities, ranging between 25 (Azores Archipelago) and 311 (Rio Grande do Sul). The overall effective population size was estimated as 299 (confidence interval = 215–412), and there was no evidence of strong or recent bottleneck effects.
- Local and regional genetic structuring among dusky grouper populations is the consequence of the species' site fidelity, distribution across multiple oceanographic boundaries, and probably also of sequential hermaphroditism that contributes to the intensity of random genetic drift.
- The spatial pattern of genetic structuring of dusky groupers is such that fisheries management and conservation of population genetic integrity will have to be pursued at the local and regional scales.
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Going,going, gone? Loss of genetic diversity in two critically endangered Australian freshwater fishes,Scaturiginichthys vermeilipinnis and Chlamydogobius squamigenus,from Great Artesian Basin springs at Edgbaston,Queensland, Australia 下载免费PDF全文
下载免费PDF全文 Leanne K. Faulks Adam Kerezsy Peter J. Unmack Jerald B. Johnson Jane M. Hughes 《水产资源保护:海洋与淡水生态系统》2017,27(1):39-50
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Margaret M. Lamont Nickolas Moreno Fatima Yedith Camacho-Sánchez H. Hugo Acosta-Sánchez Scott Glaberman Miguel Angel Reyes-Lopez Ylenia Chiari 《水产资源保护:海洋与淡水生态系统》2021,31(10):3003-3010
- The Kemp’s ridley (Lepidochelys kempii) is the world’s most endangered sea turtle species. Predominately nesting at only one beach in Mexico, this species declined to an estimated 300 females in the mid-1980s. Conservation efforts in the United States and Mexico, including a head start programme in southern Texas in which hatchlings were reared in captivity for several months before being released into the wild, resulted in the recovery of this species.
- Although genetic data have previously been used to assess the success of the head start programme and dispersal of individual adults, data on immature turtles sampled at foraging areas and adult females sampled at the main nesting beach in Mexico are lacking. Genetic characterization of immature individuals is important for understanding recruitment, survival, and population demography, while genetic data on individuals from Mexico are essential for understanding dispersal and overall genetic diversity in this species.
- To address these gaps, mitochondrial DNA data were collected from 106 immature individuals sampled at four different foraging sites in the northern Gulf of Mexico and from 18 nesting females at the primary nesting beach in Mexico.
- Two previously unknown mitochondrial DNA haplotypes were discovered among the immature individuals.
- Except for these two new haplotypes, the genetic diversity of immature individuals in the northern Gulf of Mexico closely corresponds to that of adults sampled in Mexico, which suggests that much of the diversity within the nesting population can be found among immature animals dispersing to foraging grounds, including locations in the northern Gulf of Mexico.
- Continued monitoring of the genetic variation of different life stages of this species across its distribution range will help assess the success of conservation programmes by ensuring the maintenance of genetic diversity and representation of this diversity across the species’ distribution range.
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Dayani Bailly Valéria Flavia Batista-Silva Fernanda A. Silva Cassemiro Priscila Lemes Weferson Junio da Graça Anielly Galego de Oliveira Edivando Vitor do Couto José Hilário Delconte Ferreira Reginaldo Ré Thiago Fernando Rangel Angelo Antonio Agostinho 《水产资源保护:海洋与淡水生态系统》2021,31(9):2515-2532
- Freshwater ecosystems, providing valuable goods and services to humans, have been subjected to multiple human impacts, among which climate change plays a central role in threats to species. It is expected that protected areas, the cornerstone of biodiversity conservation efforts, will assume a decisive role in protecting freshwater species from the impacts of climate change.
- This study assessed the effects of climate change on migratory fish of the second largest neotropical river basin, evaluating the effectiveness of protected areas in safeguarding fish species, and hence the ecological functions that they perform and the ecosystem resources that they provide. The present range of 23 migratory fish of economic interest in the Paraná–Paraguay basin was estimated and the responses to future climatic shifts projected to the middle and end of the 21st century were examined, quantifying predictive uncertainties.
- Changes and losses of climatically suitable areas will trigger severe contractions in range, with the greatest impact on the most valuable species in commercial fishing, where range losses are likely to surpass 65% in the future. The main channel of the Upper Paraná River and tributaries of its left margin are projected to serve as climatic refuges for many species, and such regions are not affected by high predictive uncertainty. The results revealed that protected areas do not sufficiently protect migratory fish at present, and that they will continue to offer negligible protection in the face of climate change.
- This study alerts decision makers to the potential damage to inland fishery resources from climate change and provides useful information to guide conservation strategies spatially. We advocate that the creation of new protected areas and the redesign of the existing network to encompass regions that maximize current and future occupancy of migratory fish are crucial to conserve the valuable ecological, societal, and economic benefits that they provide.