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1.
In this study the length–weight relationships of nine fish species from Xingkai (Khanka) Lake in China belonging to three families and eight genera were analyzed. A total of 273 specimens were used to estimate the relationship parameters. Four of these species (Chanodichthys dabryi, Hemibarbus maculatus, Tachysurus fulvidraco and Cyprinus carpio haematopterus) had no previous estimations and one maximum length is new to science for inclusion in FishBase.  相似文献   

2.
1. The common carp (Cyprinus carpio L.) is one of the most widely distributed and important freshwater fishes in the world. In China, the common carp has been recognised as three subspecies: C. carpio haematopterus, C. carpio rubrofuscus and C. carpio carpio. The Nanling Mountains have been suggested as providing the dividing line between C. carpio haematopterus and C. carpio rubrofuscus. However, the demographic history and gene flow of the common carp in China is not clear. 2. We collected mitochondrial COII and D‐loop sequences (1494 bp) from 241 individuals distributed in eight major river drainages across China. The objective was to provide the first investigation into population genetic structure, demographic history and migration patterns of the common carp from these river drainages, and to assess the validity of the three subspecies. 3. Phylogenetic analysis did not result in three major monophyletic lineages corresponding to the three subspecies. The Nanling Mountains do not form a border separating C. carpio haematopterus and C. carpio rubrofuscus. amova showed low population differentiation, with 11.60% of the molecular variance found among river drainages. Pairwise FST values between river drainages were moderate (0.0331–0.2617). Substantial gene flow detected in coalescent analysis between drainages showed that the Yangtze drainage was the centre from which migrants moved northward, southward and north‐westward. Human‐mediated translocation has confounded our ability to identify subspecies of common carp in China.  相似文献   

3.
《Aquatic Botany》2005,82(1):39-54
Meristematic growth and loss of distal tissue from blades of two ecologically important species in the south-east Pacific, Lessonia nigrescens and Lessonia trabeculata, was evaluated during 1 year. Comparative growth was determined by a hole-punch method, loss of distal tissue from the blades was determined by subtracting final blade length (with loss) from expected blade lengths (without loss); growth and tissue loss were transformed to fresh biomass units for calculation of inter-algae differences. The results showed that blade elongation rate increased at the beginning of spring, and declined towards the end of summer, with mean values between 0.40 and 0.08 cm day−1 for L. nigrescens, and 0.65–0.17 cm day−1 for L. trabeculata. Loss of distal tissue varied seasonally when examined as length units for both species; with mean values between 0.24 and 0.10 cm day−1 for L. nigrescens, and 0.51–0.25 cm day−1 for L. trabeculata. Variations in fresh biomass units were only observed in Lessonia trabeculata, increasing in spring, with mean values to 0.13 g (fresh weight) day−1. Annual growth and loss of distal tissue were higher in L. trabeculata (0.41 and 0.39 cm day−1, respectively) than in L nigrescens (0.19 and 0.15 cm day−1). When growth and tissue loss were considered as fresh biomass, monthly gains significantly outweighed loss of distal tissue in both species, but parallel results based on length data followed a different trend. L. trabeculata released about 50% of its growth biomass as particulate organic matter, while the comparative value for L. nigrescens was about 20%.  相似文献   

4.
Marbà N  Hemminga MA  Duarte CM 《Oecologia》2006,150(3):362-372
The allometric scaling of resource demand and translocation within seagrass clones to plant size (i.e. shoot mass and rhizome diameter), shoot production and leaf turnover was examined in situ in eight seagrass species (Cymodocea nodosa, Cymodocea serrulata, Halophila stipulacea, Halodule uninervis, Posidonia oceanica, Thalassodendron ciliatum, Thalassia hemprichii and Zostera noltii), encompassing most of the size range present in seagrass flora. One fully developed shoot on each experimental rhizome was incubated for 2–3 h with a pulse of NaH13CO3 (235 μmol) and 15NH4Cl (40 μmol). The mobilisation of incorporated tracers across the clone was examined 4 days later. Carbon and nitrogen demand for shoot production across seagrass species scaled at half of the shoot mass, whereas seagrass leaves incorporated tracers (13C and 15N) at rates proportional to the shoot mass. The shoots of all seagrass species shared resources with neighbours, particularly with younger ones. The time scales of physiological integration and the absolute amount of resources shared by seagrass ramets scaled at 2.5 power of the rhizome diameter. Hence, the ramets of larger species were physiologically connected for longer time scales and share larger absolute amounts of resources with neighbours than those of smaller species. The different pattern of resource translocation exhibited by seagrasses helps explain the ecological role displayed by these species and the success of large seagrasses colonising nutrient-poor coastal areas, where they often dominate.  相似文献   

5.

Coastal wetlands are key in regulating coastal carbon and nitrogen dynamics and contribute significantly to climate change mitigation and anthropogenic nutrient reduction. We investigated organic carbon (OC) and total nitrogen (TN) stocks and burial rates at four adjacent vegetated coastal habitats across the seascape elevation gradient of Cádiz Bay (South Spain), including one species of salt marsh, two of seagrasses, and a macroalgae. OC and TN stocks in the upper 1 m sediment layer were higher at the subtidal seagrass Cymodocea nodosa (72.3 Mg OC ha−1, 8.6 Mg TN ha−1) followed by the upper intertidal salt marsh Sporobolus maritimus (66.5 Mg OC ha−1, 5.9 Mg TN ha−1), the subtidal rhizophytic macroalgae Caulerpa prolifera (62.2 Mg OC ha−1, 7.2 Mg TN ha−1), and the lower intertidal seagrass Zostera noltei (52.8 Mg OC ha−1, 5.2 Mg TN ha−1). The sedimentation rates increased from lower to higher elevation, from the intertidal salt marsh (0.24 g cm−2 y−1) to the subtidal macroalgae (0.12 g cm−2 y−1). The organic carbon burial rate was highest at the intertidal salt marsh (91 ± 31 g OC m−2 y−1), followed by the intertidal seagrass, (44 ± 15 g OC m−2 y−1), the subtidal seagrass (39 ± 6 g OC m−2 y−1), and the subtidal macroalgae (28 ± 4 g OC m−2 y−1). Total nitrogen burial rates were similar among the three lower vegetation types, ranging from 5 ± 2 to 3 ± 1 g TN m−2 y−1, and peaked at S. maritimus salt marsh with 7 ± 1 g TN m−2 y−1. The contribution of allochthonous sources to the sedimentary organic matter decreased with elevation, from 72% in C. prolifera to 33% at S. maritimus. Our results highlight the need of using habitat-specific OC and TN stocks and burial rates to improve our ability to predict OC and TN sequestration capacity of vegetated coastal habitats at the seascape level. We also demonstrated that the stocks and burial rates in C. prolifera habitats were within the range of well-accepted blue carbon ecosystems such as seagrass meadows and salt marshes.

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6.
The economic value of ecosystem services of vegetated habitats (seagrass and macroalgal beds) has been estimated to be among the highest of the various ecosystems on earth. However, fish production has not been included in the evaluations due to the difficulty of quantitative estimation of fish production in the field. In the present study, annual production and economic value of wild juvenile black rockfish, Sebastes cheni, a dominant fish species in seagrass and macroalgal beds in the central Seto Inland Sea were estimated. Juvenile S. cheni migrated into vegetated habitats at about 20 mm total length (TL) and grew up to about 60 mm TL by late May. Juvenile abundance was highest in April (2007) or March (2008). Eight cohorts with the same extrusion period (each cohort covering a 10-day period) were identified using otolith daily increments. The annual estimates of S. cheni juvenile production were 13,080 g ha−1 year−1 in 2007 and 18,360 g −1 year−1 in 2008. Based on the unit price of artificially raised S. cheni juveniles, the economic value of the annual wild juvenile production was converted to 654,000 JPY (Japanese yen: 100 JPY = ca. 1 USD) ha−1 year−1 for 2007 and 918,000 JPY ha−1 year−1 for 2008. Analyses of stomach contents and stable isotope (δ13C or δ15N) showed that juvenile S. cheni were highly dependent on copepods. The planktonic trophic pathway originating from phytoplankton supports the majority of the juvenile black rockfish production during the post-migration period (20–60 mm TL) in the seagrass and macroalgal beds through the production of copepod zooplankton. The total economic value of the ecosystem services of the vegetated habitat is suggested to be much higher than estimates in previous studies if the provisioning and regulating services which originate from fish production were included in the estimates.  相似文献   

7.
Recent research has identified a need for seagrass habitat management plans to be based on landscape-level approaches as they offer a more appropriate scale for large mobile fauna than smaller scales. Also, conservation decisions are more likely to be a choice between different seagrass beds rather than parts of individual beds. The present study examined the spatial utilisation of subtidal seagrass beds by fish around the coast of Jersey, English Channel (49°N 02°W) with the aim of identifying influential scales of complexity. A hierarchical-scale of landscape configuration and habitat characteristics was measured for eight seagrass beds using aerial photographic analysis (e.g. core area, contiguity and other landscape metrics), digital echo-sounder data (e.g. depth, canopy height) and diver surveys (e.g. epiphyte load). The contributions of these variables as predictors of functional fish groups were explored using multiple linear regression models. Results indicated that more fragmented seagrass beds supported lower numbers of fish species than more homogenous seagrass landscapes (squared semi-partial correlation coefficient, sr2 = − 0.3). Densities of juveniles of larger fish species showed a negative relationship with increased fragmentation of the seagrass (sr2 = − 0.34). At smaller scales of structural complexity the densities of cryptic fish were related positively to canopy height (sr2 = 0.46). At night, fewer patterns could be explained by the independent variables in the model, which was attributed to the greater movement of fish between the seagrass and adjacent habitats to forage, and a breakdown in the association with seagrass habitat as a refuge from predation.  相似文献   

8.
Chile is an important producer of brown seaweeds representing 10% of world supply. Landings of Chilean kelp fluctuated between 40,000 t.year−1 in the early ‘80s to 250,000 t.year−1 more recently. Commercialized algae come from natural populations and no mass-cultures of involved species have been established. Four species of brown algae are commercially collected in the country: Lessonia trabeculata, L. nigrescens, Macrocystis pyrifera and M. integrifolia. Since 2000, the demand of alginate sources and food for cultivated abalones dramatically raised the harvesting of these species. Direct evaluations of Lessonia spp. and Macrocystis standing-stocks were made along 700 km of coast in northern Chile. Lessonia spp. estimated populations exceed 900,000 t, whereas M. integrifolia does not exceed 300 t. The insights provided indicate that sustainability of Chilean kelp subjected to intense harvesting would require management programs including the following bio-ecological recommendations: (1) to harvest the entire plant including the holdfast; (2) to harvest plants larger than 20 cm in diameter; (3) to harvest plants sparsely, selecting mayor specimens; (4) rotation of harvesting areas; and (5) for Macrocystis, to cut the canopy 1–2 m from the surface. They must be implemented in a National Program of Kelp Management, elaborated by government, scientists, fisherman, and industry.  相似文献   

9.
Length-weight relationship was estimated for three fish species, including: Lethrinus microdon (Valenciennes, 1,830), Sphyraena jello (Cuvier, 1829) and Euthynnus affinis (Cantor, 1849). Specimens were sampled between May 2014 and June 2015 from the fish caught by the local artisanal fishery and landed in main fishing landing site of Mocka city. Values of b for fish ranged from 2.644 for S. jello to 2.706 for E. affinis and 3.187 for L. microdon. The determination coefficient (r2) between total length and total body weight ranged from .952 in E. affinis to 0.957 in S. jello and 0.960 in L. microdon.  相似文献   

10.
The length–weight relationships (LWRs) were studied of 441 fish individuals covering six families, eight genera and 12 freshwater species (L. dyochilus, L. calbasu, L. gonius, L. fimbriatus, P. sarana, L. boggut, C. mrigala, W. attu, B. bagarius, E. vacha, N. notopterus and S. aor) captured in the River Ken (tributary of the Yamuna River) from December 2007 to January 2009. The b value ranged from 3.52 for Cirrihinus mrigala, to 2.11 for Labeo gonius, with a mean of 3.03 at p < 0.001 for all species. The present observations are significant for conservation and management because the Ken River has been approved under India’s first interlinking plan with the River Betwa. The objective was to evaluate the LWRs of the freshwater fish species of an unimpacted and understudied river, which serves as a baseline for comparison to other relatively altered tropical Indian rivers.  相似文献   

11.
Stable isotope (δ13C and δ15N) and gut content analyses were used to investigate size‐related feeding habits of four reef fishes (the beaugregory Stegastes leucostictus, the french grunt Haemulon flavolineatum, the schoolmaster snapper Lutjanus apodus and the yellowtail snapper Ocyurus chrysurus) inhabiting an offshore (non‐estuarine) mangrove islet off Belize, Central America. Comparisons of isotopic niche space and Schoener diet similarity index suggested a low to moderate degree of niche overlap between fish size groups. The δ13C gradient between mangrove and seagrass prey as well as results of Bayesian mixing models revealed that sampled fishes relied mostly on seagrass prey items. Only small and large juveniles of the carnivorous species L. apodus derived a part of their diet from mangroves by targeting mangrove‐associated Grapsidae crabs and fish prey, respectively. Isotopic niche shifts were particularly obvious for carnivorous fishes that ingested larger prey items (Xanthidae crabs and fishes) during their ontogeny. The utilization of mangrove food resources is less than expected and depends on the ecology and life history of the fish species considered. This research highlights that mangrove‐derived carbon contributed relatively little to the diets of four fish taxa from an offshore mangrove islet.  相似文献   

12.
Length–weight relationships (LWRs) were estimated for eight native fish species collected in the lower reaches of the Pearl River, Guangdong Province, South China. Fish were sampled in March and September 2014 and January 2015, using gillnets with various mesh sizes (5–8 cm) and trawl nets with a 3 cm mesh size. A total of 568 specimens of the eight species were analyzed. The r2 values for these species ranged from 0.951 to 0.991. The b values ranged from 3.00 for Takifugu ocellatus and Moolgarda cunnesius, to 3.57 for Clupanodon thrissa. New maximum total lengths are recorded for Takifugu ocellatus (17.6 cm) and Liza carinata (24.4 cm). For five species (Clupanodon thrissa, Megalobrama terminalis, Collichthys lucidus, Coilia grayii, Takifugu ocellatus), the LWRs are presented to fishbase for the first time.  相似文献   

13.
Settlement of fish to seagrass with low leaf densities was investigated by a field experiment in Botany Bay, NSW. Artificial seagrass units (ASU) were used to simulate isolated seagrass habitats of 0, 25, 50, 100, 200 and 400 leaves m-2. A total of 369 fish of 21 species settled in the experimental units during a 6 week period. The labrid, Achoerodus viridis, made up almost 70% of these individuals. The abundance of recently settled A. viridis increased greatly between 0 and 25 leaves m -2, At more than 25 leaves m-2, A. viridis settled in approximately equal numbers. Patterns of settlement for all other species combined were similar to those for A. viridis. During the experiment, an epiphytic alga. Giffordia mitchellae, colonized and grew on the ASU. The alga increased the structure associated with the experimental units. Treatment leaf densities could thus be regarded only as relative measures of shelter. At low leaf densities, fish settlement increased with increasing algal cover; at higher leaf densities, the opposite occurred. The rapid increase in abundance of recently settled fish over a relatively narrow range of leaf densities above zero implies that small increases in shelter can have large effects on settlement of larval fish.  相似文献   

14.
Among thiol‐dependent peroxidases (TDPs) peroxiredoxins (PRXs) standout, since they are enzymes capable of reducing hydrogen peroxide, alkylhydroperoxides and peroxynitrite, and have been detected in a proteomic study of the copper‐tolerant species Scytosiphon gracilis. In order to determine the importance of these enzymes in copper‐stress tolerance, TDP activity and type II peroxiredoxin (II PRX) protein expression were compared between the opportunistic S. gracilis and the brown kelp Lessonia nigrescens, a species absent from copper‐impacted sites due to insufficient copper‐tolerance mechanisms. Individuals of both species were cultured with increasing copper concentrations (0–300 µg l?1 Cu) for 96 h and TDP activity and lipoperoxides (LPXs) were determined together with II PRX expression by immunofluorescence and Western blot analysis. The results showed that TDP activity was higher in S. gracilis than L. nigrescens in all copper concentrations, independent of the reducing agent used (dithiothreitol, thioredoxin or glutaredoxin). This activity was copper inhibited in L. nigrescens at lower copper concentrations (20 µg l?1 Cu) compared to S. gracilis (100 µg l?1 Cu). The loss of activity coincided in both species with an increase in LPX, which suggests that TDP may control LPX production. Moreover, II PRX protein levels increased under copper stress only in S. gracilis. These results suggest that in S. gracilis TDP, particularly type II peroxiredoxin (II PRX), acts as an active antioxidant barrier attenuating the LPX levels generated by copper, which is not the case in L. nigrescens. Thus, from an ecological point of view these results help explaining the inability of L. nigrescens to flourish in copper‐enriched environments.  相似文献   

15.
This study reports the length–weight relationships (LWRs) of four small indigenous species, Trichogaster lalius (Hamilton, 1822), Nandus meni (Hossain & Sarker, 2013), Lepidocephalichthys annandalei (Chaudhuri, 1912) and Botia dario (Hamilton, 1822) collected between July 2015 and August 2016 from fishermen's catches landed in an inland fish landing center, northeastern Bangladesh. In the study, a new maximum total length (TL) is given for L. annandalei and LWRs of three species T. lalius, N. meni and L. annandalei for the first time in FishBase. Estimated LWRs were W = .014 TL3.17, (r2 = .982) for T. lalius, W = .006 TL3.38, (r2 = .961) for N. meni, W = .004 TL3.27, (r2 = .965) for L. annandalei and W = .020 TL2.87, (r2 = .978) for B. dario.  相似文献   

16.
Mangroves and seagrass beds have long been perceived as important nurseries for many fish species. While there is growing evidence from the Western Atlantic that mangrove habitats are intricately connected to coral reefs through ontogenetic fish migrations, there is an ongoing debate of the value of these coastal ecosystems in the Indo-Pacific. The present study used natural tags, viz. otolith stable carbon and oxygen isotopes, to investigate for the first time the degree to which multiple tropical juvenile habitats subsidize coral reef fish populations in the Indo Pacific (Tanzania). Otoliths of three reef fish species (Lethrinus harak, L. lentjan and Lutjanus fulviflamma) were collected in mangrove, seagrass and coral reef habitats and analyzed for stable isotope ratios in the juvenile and adult otolith zones. δ13C signatures were significantly depleted in the juvenile compared to the adult zones, indicative of different habitat use through ontogeny. Maximum likelihood analysis identified that 82% of adult reef L. harak had resided in either mangrove (29%) or seagrass (53%) or reef (18%) habitats as juveniles. Of adult L. fulviflamma caught from offshore reefs, 99% had passed through mangroves habitats as juveniles. In contrast, L. lentjan adults originated predominantly from coral reefs (65–72%) as opposed to inshore vegetated habitats (28–35%). This study presents conclusive evidence for a nursery role of Indo-Pacific mangrove habitats for reef fish populations. It shows that intertidal habitats that are only temporarily available can form an important juvenile habitat for some species, and that reef fish populations are often replenished by multiple coastal habitats. Maintaining connectivity between inshore vegetated habitats and coral reefs, and conserving habitat mosaics rather than single nursery habitats, is a major priority for the sustainability of various Indo Pacific fish populations.  相似文献   

17.
Until the recent use of molecular markers, species diversity of Lobophora, an ecologically important brown algal genus with a worldwide distribution in temperate and tropical seas, has been critically underestimated. Using a DNA‐based taxonomic approach, we re‐examined diversity of the genus from New Caledonia in the Southwest Pacific Ocean. First, species were delineated using general mixed Yule coalescent‐based and barcoding gap approaches applied to a mitochondrial cox3 data set. Results were subsequently confirmed using chloroplast psbA and rbcL data sets. Species delimitation analyses agreed well across markers and delimitation algorithms, with the barcoding gap approach being slightly more conservative. Analyses of the cox3 data set resulted in 31–39 molecular operational taxonomic units (MOTUs), four of which are previously described species (L. asiatica, L. crassa, L. nigrescens s.l., L. pachyventera). Of the remaining MOTUs for which we obtained a representative number of sequences and results are corroborated across analyses and genes, we described 10 species de novo: L. abaculusa, L. abscondita, L. densa, L. dimorpha, L. gibbera, L. hederacea, L. monticola, L. petila, L. rosacea, and L. undulata. Our study presents an excellent case of how a traditional morphology‐based taxonomy fails to provide accurate estimates of algal diversity. Furthermore, the level of Lobophora diversity unveiled from a single locality in the Pacific Ocean raises important questions with respect to the global diversity of the genus, the distributions and range sizes of the individual species, as well as the mechanisms facilitating coexistence.  相似文献   

18.
The photosynthetic responses of the tropical tree species Acacia nigrescens Oliv. grown at different atmospheric CO2 concentrations—from sub-ambient to super-ambient—have been studied. Light-saturated rates of net photosynthesis (A sat) in A. nigrescens, measured after 120 days exposure, increased significantly from sub-ambient (196 μL L−1) to current ambient (386 μL L−1) CO2 growth conditions but did not increase any further as [CO2] became super-ambient (597 μL L−1). Examination of photosynthetic CO2 response curves, leaf nitrogen content, and leaf thickness showed that this acclimation was most likely caused by reduction in Rubisco activity and a shift towards ribulose-1,5-bisphosphate regeneration-limited photosynthesis, but not a consequence of changes in mesophyll conductance. Also, measurements of the maximum efficiency of PSII and the carotenoid to chlorophyll ratio of leaves indicated that it was unlikely that the pattern of A sat seen was a consequence of growth [CO2] induced stress. Many of the photosynthetic responses examined were not linear with respect to the concentration of CO2 but could be explained by current models of photosynthesis.  相似文献   

19.
This study provides the first report of length–weight relationships (LWRs) for three fish species collected from the Yalong River, one of the tributaries to the upper reaches of the Yangtze River, China. The LWRs of these fish species were BW = 0.0070TL3.0539 (r2 = 0.9662) for Schizothorax wangchiachii, BW=0.0134TL2.8523 (r2 = 0.9676) for Schizopygopsis malacanthus, and BW=0.0143TL2.9253 (r2 = 0.8538) for Euchiloglanis kishinouyei, respectively. Also investigated were the spawning season, absolute fecundity and main food items of the three fish species in the natural environment. In addition, new maximum sizes for the three species are provided.  相似文献   

20.
Zhou JF  Wu QJ  Ye YZ  Tong JG 《Genetica》2003,119(1):93-97
Although common carp is the major fish species in Asian and European aquaculture and many domestic varieties have occurred, there is a controversy about the origination of European domestic common carp. Some scientists affirmed that the ancestor of European domestic common carp was Danube River wild common carp, but others considered it might be Asian common carp. For elucidating origination of European domestic common carp, we chose two representative European domestic common carp strains (German mirror carp and Russian scattered scaled mirror carp) and one wild common carp strain of Cyprinus carpio carpio subspecies (Volga River wild common carp) and two Asian common carp strains, the Yangtze River wild common carp (Cyprinus carpio haematopterus) and traditionally domestic Xingguo red common carp, as experimental materials. ND5–ND6 and D-loop segments of mitochondrial DNA were amplified by polymerase chain reaction and analyzed through restriction fragment length polymorphism (RFLP) and sequencing respectively. The results revealed that HaeIII and DdeI digestion patterns of ND5–ND6 segment and sequences of control region were different between European subspecies C. carpio carpio and Asian subspecies C. carpio haematopterus. Phylogenetic analysis showed that German mirror carp and Russian scattered scaled mirror carp belonged to two subspecies, C. carpio carpio and C. carpio haematopterus, respectively. Therefore, there were different ancestors for domestic carp in Europe: German mirror carp was domesticated from European subspecies C. carpio carpio and Russian scattered scaled mirror carp originated from Asian subspecies C. carpio haematopterus.  相似文献   

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