共查询到20条相似文献,搜索用时 15 毫秒
1.
Morphological and ecological traits of the Mongolian grayling Thymallus brevirostrisfrom Hoton Nur Lake are investigated with consideration of the assumption for a possible presence in this species of two morpho-ecological
forms. The data on growth, feeding, sex, and age composition are presented. Plastic and meristic characters, distribution
of fish in the water body, and feeding are analyzed. Within the age range of 3+ to 6+, in the population there are two groups
of specimens differing in growth rate, diet, and some plastic characters of the head. These two groups may be designated as
“predatory” and “benthos-feeding” forms. The predatory form lacks specimens of junior age groups; the benthos_feeding form
lacks specimens older than seven years. Validity of these morpho-ecological groups is discussed. 相似文献
2.
The trophic ecology of the emerald notothen Trematomus bernacchii was investigated using a sample of 284 specimens collected in the coastal waters of Terra Nova Bay (Ross Sea) during the summer season 1990–1991. The stomach-content analysis provided data on feeding habits and trophic niche breadth. Overall, 72 taxa of food items were identified; the most important as prey were infaunal and epifaunal polychaetes, amphipods and molluscs. Food of secondary importance comprised isopods, pycnogonids, fish and fish eggs. Several other taxa, such as euphausiids, mysids, decapods, echinoids, holothurians, priapulids and thaliaceans constituted food eaten in very small amounts and only occasionally. On the basis of their diet, T. bernacchii can be considered generalized feeders, with a wide niche breadth composed almost exclusively of benthic organisms. A cluster analysis was conducted to compare stomach-content data of subsamples selected on the basis of fish size and sampling depth, aiming to determine diet diversity and niche breadth, as well as factors involved in reducing intraspecific competition for food resources. Diet was different for fish sampled in shallow (90 m depth) and deeper waters (>90 m depth): while the first group fed mostly on bivalves (Adamussium colbecki) and amphipods, the latter preferred infaunal-epifaunal polychaetes. Conversely, fish size did not contribute significantly to diet diversification. According to our data and published data on feeding behaviour and sensory ecology, we conclude that in this species the intraspecific competition for food is reduced, either through habitat heterogeneity or different foraging strategies. 相似文献
3.
Morphological and behavioral traits of Rasbora paviei from river and lake environments are studied. For investigations, the fish were caught from the middle reaches of the Cai
River and from the inshore zone of the Kam Lam Reservoir (Khanh Hoa Province, Central Vietnam). Phenotypic differences are
found in river and lake fish groups. Experimentally, differences in tactics and efficiency of defensive behavior are found
in specimens from different habitats in the presence of a predator—Lepisosteus sp. (Lepisosteidae). In river specimens of Rasbora, the defensive reaction is more efficient in comparison with specimens from the reservoir. The river specimens of Rasbora used predominantly the tactics of group defense from the predator and stayed in a school longer than the lake specimens. 相似文献
4.
Length–weight relationships of nine fish species from the Tongjiang section of the Songhua River,China
下载免费PDF全文
![点击此处可从《Zeitschrift fur angewandte Ichthyologie》网站下载免费的PDF全文](/ch/ext_images/free.gif)
T. B. Huo M. Y. Yuan J. L. Wang P. L. Li W. Liu X. C. Wu 《Zeitschrift fur angewandte Ichthyologie》2017,33(4):848-850
Length–weight relationships were evaluated for nine fish species from the Tongjiang section of the Songhua River in China. A total of 675 fish specimens were collected from 4 May to 29 October 2014. Length–weight relationships for six fish species (Romanogobio tenuicorpus, Leuciscus waleckii, Opsariichthys bidens, Microphysogobio amurensis, Pelteobagrus ussuriensis and Misgurnus mohoity) were new to FishBase in 2015, but the length–weight relationships of P. ussuriensis was studied by Ma in 2015. New data on M. mohoity is offered, and this study also shows new maximum total lengths for three fish species. The r2 values ranged from .95 to .99. Values of b varied from 2.504 to 3.471. 相似文献
5.
Length–weight relationship of six freshwater fish species in upper‐middle Tocantins River basin (Brazil)
下载免费PDF全文
![点击此处可从《Zeitschrift fur angewandte Ichthyologie》网站下载免费的PDF全文](/ch/ext_images/free.gif)
D. C. O. Rosa R. Bartolette B. E. Soares M. F. G. Brito 《Zeitschrift fur angewandte Ichthyologie》2018,34(4):1021-1024
Length–weight relationships (LWRs) were analyzed for six abundant fish species in the upper‐middle Tocantins River, northeastern Brazil. Analyses included data from 486 specimens sampled in five expeditions between August 2013 and May 2015 by gillnets. New maximum values of total lengths for the literature and FishBase were presented for six species, as well as first time estimates of LWR for Galeocharax gulo, Curimata acutirostris and Aphanotorulus emarginatus. 相似文献
6.
A. Meraner S. Baric J. Dalla Via 《Comparative biochemistry and physiology. Part D, Genomics & proteomics》2008,3(1):36
The identification of pure indigenous fish from hybridised populations represents a key issue in fisheries management and conservation biology. In the present study an approach for selection of purebred marble trout (Salmo trutta marmoratus C.) individuals out of admixed populations was set up and assessed. In a first step, baseline data sets of pure marble trout and pure brown trout specimens based on twelve microsatellite loci were used to simulate five consecutive generations of admixture. The baseline and the resulting simulation data sets were then combined with data of a ‘real’ hybridised marble trout population to perform a single individual assignment test as implemented in STRUCTURE. By this procedure the assignment approach was calibrated and it was possible to compare admixture coefficients obtained for individuals from different populations. The ranking of individual admixture coefficients on a plot and comparison with simulated data revealed that the test population was composed of pure marble trout individuals, first generation hybrids between marble trout and brown trout, and hybrid backcross specimens between both groups. However, by defining a critical q-value of 0.1 and additionally integrating individual sequence data of the mtDNA control region, it was possible to indicate individuals, which could be selected for the establishment of a pure marble trout strain. 相似文献
7.
In comparison with other bathydraconids, all species of the genus Bathydraco are poorly known from an ecological perspective. The diet of juvenile Bathydraco marri Norman, 1938 was studied for the first time in specimens collected in the southwestern Ross Sea during summer 1998. Fish
were collected in a single otter trawl catch at 330–340 m depth. The stomach content analysis showed that this species fed
exclusively on crustaceans. Overall, 20 prey taxa were identified to genus or species level. Mysids, amphipods and copepods
were the most important prey in decreasing order of importance. Other prey, such as Euphausia superba, isopods and tanaids were eaten occasionally and in very small amounts. A multivariate analysis was applied to feeding data
to assess ontogenetic or sex-related changes in diet. No difference was detected between sexes, whereas diet of small and
large fish differed in some degree. An ontogenetic shift from small and pelagic crustaceans such as copepods to benthic–benthopelagic
prey such as amphipods and mysids was observed. Relating present results with published data on physiological characteristics
of B. marri, it was possible to infer their feeding behaviour and mode of life. Like other bathydraconids, this species appeared to be
an inactive and sluggish fish, which relied on more or less motile benthic or epibenthic prey adopting a “sit and wait” feeding
strategy. On the other hand, smaller fish seem to be more active, feeding also on pelagic prey such as copepods that can be
seasonally abundant, thus reducing the intraspecific competition for food. 相似文献
8.
Length–weight and length–length relationships of 26 fish species from the Yiluo River,a tributary of the Yellow River,China
下载免费PDF全文
![点击此处可从《Zeitschrift fur angewandte Ichthyologie》网站下载免费的PDF全文](/ch/ext_images/free.gif)
《Zeitschrift fur angewandte Ichthyologie》2017,33(6):1270-1273
From February to October 2016, a total of 9,754 fish specimens were collected from the Yiluo River, a tributary of the Yellow River, China's second longest river. Based on these samples, length–weight relationships (LWRs) and length–length relationships (LLRs) were estimated for 26 species. Among these data, LWRs for 1 species, LLRs for 11 species, and maximum total lengths for six species were not previously recorded in FishBase. The a values of the LWRs varied between 0.0019 and 0.0116, and b values from 2.805 to 3.883. All regressions for LWRs and LLRs were highly significant (p < .001). These results will be useful for sustainable management and conservation of the fish resources in the Yiluo River and the Yellow River ecosystem. 相似文献
9.
Von N. Peters A. Scholl H. Wilkens 《Journal of Zoological Systematics and Evolutionary Research》1975,13(2):110-124
The Micos Population–cave fish in statu nascendi or hybrid? Observations on the evolution of cavernicoles The Micos-Cave in the Sierra de la Colmena in the State of San Luis Potosi, Mexico, contains a cavernicolous population of Astyanax mexicanus, whose members are for the most part blind, but, in contrast to other cave dwelling populations of the same species, appear almost normal in their pigmentation. Besides these, there are also large eyed and pigmented specimens to be found in this cave. Any transitional stages between the blind and the normal visioned fish are lacking. Offspring of the blind cavernicoles that are raised under light conditions develop a superficially lying eye which is markedly smaller than normal, attaining its size proportional to the light-intensity of the experimental conditions. The size and structure of the eye-remnants of the blind fish as well as the eyes of their offspring are considerably more variable than in the river specimens. Crossings of the blind Micos fish with the river fish Astyanax and also with a blind and unpigmented troglobiont of the same species - Sabinos fish - result in both cases in a more or less intermediate F1-hybrid. A strict inbreeding within the Micos fish, selecting specimens with especially large eyes, produced animals whose eyes are comparable to those of the river fish after only three offspring generations. Electrophoresis studies on the allozyme variability at various loci prove that the Micos fish is genetically only slightly different compared to the river fish. On the other hand in some allele frequencies there is an alternative variation between the two. The Micos fish also differs from the typical troglobionts which are monomorphic at almost all loci examined and also possess alleles that are not found in the river form. Based on the genetic constitution, the Micos fish and the river fish found in the cave do not form a panmictic population. It is also doubtful that the Micos fish is the progeny of a hybrid swarm which previously resulted from a cross between a real troglobiont and the newly arrived river fish, because the Micos fish is in every characteristic genetically very similar to the river fish, whereas no clear traces of troglobiont relationship are found. Thus the Micos fish actually appears to be a cave form in statu nascendi against which the river fish that find their way in from time to time cannot compete. 相似文献
10.
F. Pereira Arantes H. Batista dos Santos E. Rizzo Y. Sato N. Bazzoli 《Zeitschrift fur angewandte Ichthyologie》2011,27(3):847-853
Generally, migratory fish can complete vitellogenesis even when the migration process is interrupted; however, final oocyte maturation does not occur and therefore there is no spawning. To evaluate the reproductive process of migratory fish inside the reservoir of the Três Marias Dam (a lentic environment), 90 female and 81 male Prochilodus argenteus and 172 female and 115 male Prochilodus costatus were captured in this environment. Males and females from both species in the resting stage were pre‐dominant, and the highest frequency of specimens in advanced maturation stages occurred in November, December and January. According to histological analysis, ovarian regression was frequent and vitellogenic oocytes undergoing atresia were intensely observed, moreover, no fish with ovaries and testes with characteristics of spawning and spermiation, respectively, were captured. This indicated that both species were preparing for reproduction and reaching advanced gonad maturation, but were unable to complete the process of reproduction in this environment. The data from this study indicate that the modification of portions of rivers to lentic environments can have a negative impact on the reproductive process of migratory fish in freshwater. 相似文献
11.
Travis Ingram 《Biological journal of the Linnean Society. Linnean Society of London》2015,116(4):805-818
Body shape variation is integrally related to many aspects of fish ecology, including locomotion and foraging, and can indicate the functional diversity of fish assemblages. Few studies have thoroughly characterized body shape in a diverse marine fish clade, or investigated both temporal and spatial patterns of variation in body shape disparity. Here, I use digital photographs to measure geometric body shape in 66 species of north‐east Pacific rockfish (Sebastes spp.), including a correction for error introduced by arching of specimens. Different components of interspecific shape variation show associations with fish size, depth habitat, trophic niche and phylogenetic relationships. Overall, the accumulation of body shape disparity appears to have been near‐constant over time, and shows little variation across the latitudinal range of rockfish. 相似文献
12.
Length‐weight relationships of three fish species collected by recreational fishing in the northern coast of Yucatan Peninsula,Mexico
下载免费PDF全文
![点击此处可从《Zeitschrift fur angewandte Ichthyologie》网站下载免费的PDF全文](/ch/ext_images/free.gif)
G. Poot‐López R. Díaz‐Gamboa C. González‐Salas S. Guillén‐Hernández 《Zeitschrift fur angewandte Ichthyologie》2017,33(6):1249-1250
Length‐weight relationship (LWR) was estimated for three fish species from the northern coast of Yucatan peninsula in the Gulf of Mexico. All specimens were monthly collected from September 2015 to October 2016 by recreational fishing (handlining). A total of 408 individuals (15 Calamus campechanus, 9 Opsanus beta and 384 Sphoeroides nephelus) were sampled and analyzed. Information regarding LWR data for one of these species were not yet available in FishBase database, two of them have limited data and a new record of maximum length is presented. 相似文献
13.
Cristian Camilo Martínez‐González William González‐Daza José Iván Mojica 《Zeitschrift fur angewandte Ichthyologie》2018,34(5):1216-1219
This study estimated the a and b parameters of the length–weight relationships of 15 fishes from the Mira and Caunapí rivers, San Andrés de Tumaco, Nariño, Colombia. The specimens were captured during four samplings periods between 2015 and 2016 using a different a combination of fishing gillnets and electrofishing. The a values ranged from 0.0002 to 0.04 and b values ranged from 2.86 to 3.6. The data presented here are tentative estimates because the fish have been weighted and measured after fixation in formalin and ethanol, however, these data are references for weight‐length relationship for 15 species, the maximum weight for the same 15, and new maximum lengths for 3 species. 相似文献
14.
The fish swallowed by the burbot caught with gill nets in the Volzhskii reach of the Rybinskoe water reservoir in 2007 are
investigated. Based on the teretial body shape, the absence of a swim bladder, the presence of a pelvic disc, the dimensions
of the skull, the body length, the body weight, and the age, the specimens found in the gut of the burbot are identified as
round goby Neogobius melanostomus (Pallas). The round goby should be regarded as an adventive (invasive) species because it is not distributed in different
biotopes of the Rybinskoe water reservoir. 相似文献
15.
Mario La Mesa 《Polar Biology》2007,30(10):1219-1226
Juvenile Antarctic toothfish (Dissostichus mawsoni) collected off the South Shetland Islands (CCAMLR Subarea 48.1) were aged by counting the presumed daily increments in the
sagittal otoliths. The timing and position of the first annulus was examined for each individual fish from 10 to 13 cm TL.
Under reflected light at low magnification, the otolith sections exhibited a wide opaque nucleus, with no evidence of deposition
of the first translucent zone. The average measurement of ventral and dorsal radii of these sections were, respectively, 603
and 768 μm, consistently less than the measurements done in previously estimated 1 year old fish caught in the same area.
All specimens aged in the present study were approximately 1 year old fish, with an age range between 365 and 431 days, suggesting
a significant underestimation of age in the previous studies. The value of ageing precision indices calculated was relatively
low, supporting the reliability of the reading technique applied. Two checks were easily identified in the core of all otolith
sections, interpreted tentatively as hatching and first exogenous feeding checks. Back-calculating from the time of capture,
the hatching period of D. mawsoni was estimated to occur throughout the summer season, from November to February. In conclusion, the delay in timing of deposition
of the first translucent zone, which occurs in the second winter from hatching, should be taken into account in future studies
on ageing Antarctic toothfish, as well as in the stock assessment models based on length at age data. 相似文献
16.
The composition of the diet of the Indo-Pacific cornetfish Fistularia commersonii from the SE Aegean Sea is described. The stomach contents of 245 specimens collected between September 2004 and March 2005
were examined. Dietary comparisons were made reflecting the relationship between diet composition, time of year, and fish
size. Correlation between predator length and prey length was significant. The diet of the blue cornetfish consists of 96%
by number and 99.95% by weight of fish. Size classification and habitat of prey groups (benthic, supra-benthic, and pelagic)
showed that with increased body length the blue cornetfish extended its diet to larger prey and more generalist feeding. Spicara smaris, Boops boops, and Mullidae spp. were the most abundant prey by weight whereas a variety of small benthic fish (especially gobiids) and
newly hatched fish constituted the largest number of prey items. Length–weight relationships for the cornetfish were investigated. 相似文献
17.
Studies performed in Pacific waters of the northern Kuril Islands from May to August 2003–2007 demonstrated that not only
juveniles of Pleurogrammus monopterygius but also its adult specimens are found in the near-surface layer. Some adult fish migrate to the near-surface layer for feeding,
while occurrence in this layer for other specimens is related to the change of spawning grounds. Among specimens with a length
of 36–48 cm, females comprise 86.2%; among specimens with a length of 22–28 cm, females comprise 56%. Migrations in the near-surface
layer have no mass pattern. 相似文献
18.
Daniel A. Fernndez Daniel O. Bruno Facundo M. Llompart 《Zeitschrift fur angewandte Ichthyologie》2019,35(2):597-599
This study presents length‐weight relationships (LWR) for six species of fishes of the Suborder Notothenioidei that inhabit the sub‐Antarctic waters of the Beagle Channel (Argentina). These species represent five of the nine families of this Suborder. The specimens belong to historical fish collections in the area (from 1987 to 1990) using gill and trammel nets. All species but Eleginops maclovinus had no previous LWR estimates. The coefficient of determination (r2) ranged from 0.91 to 0.99 and b values ranged from 2.74 to 3.2. Harpagifer bispinis was the only species with a b value lower than three. This information is useful to predict the weight from the length data and to provide insights into the ecology of sub‐Antarctic nototheniod fish. 相似文献
19.
During surveys of the biodiversity of fish parasites in the Okavango River and Delta, Botswana, specimens of Lamproglena von Nordmann, 1832 were found associated with the African pike Hepsetus odoe (Bloch). This Lamproglena species distinctly differs from all known species based on morphological features, in particular the cephalothorax and the maxilliped; it is described as L. hepseti n. sp. and is specific to its host, the African pike. 相似文献
20.
The metazoan parasites of the Danube bleak, Alburnus chalcoides (Güldenstädt, 1772), were determined in Tödürge Lake, since the parasite fish fauna had not yet been studied in this system. A total of 106 specimens were collected from October 2004 to September 2005. Six parasite species were found: two monogeneans (Diplozoon paradoxum and Diplozoon megan), one digenean (Posthodiplostomum cuticola), one cestode (Bothriocephalus acheilognathi), one nematod (Rhabdochona sp.), and one copepod (Argulus foliaceus). About 87.7% of the Danube bleak examined were infected by at least one parasite: Rhabdochona sp. (4080 specimens), Posthodiplostomum cuticola (312 specimens) and Diplozoon megan (159 specimens) being the dominant parasites. Only 33% of the fish carried one parasitic species whilst the remainder had two (21.7%), three (17.9%) and four different species (15.1%). The frequency of infestation changed according to seasonal conditions, with a maximum 94.3% observed in spring. Occurrence, density, seasonal changes, and preferences of the parasites species for various ages and size groups of the bleak were identified, despite the limited overall sample size. D. paradoxum, D. megan, P. cuticola, B. acheilognathi, Rhabdochona sp. and A. foliaceus were determined for the first time as parasites of Danube bleak in Turkey. D. megan was also a new record for the fish parasite fauna of Turkey. 相似文献