共查询到20条相似文献，搜索用时 15 毫秒
1.
Comparisons between the stable isotope composition of carbon in collagen excized from juvenile (freshwater) and adult (marine) portions of scales from Atlantic salmon Salmo salar demonstrated that c. 75% of carbon analysed in the 'juvenile' portion of the scale derives from later formed collagen. Scale collagen analyses were effectively restricted to the last season of growth. 相似文献
2.
Peter Grønkjær Rasmus Ottosen Thor Joensen Lee Reeve Einar E. Nielsen Rasmus Hedeholm 《Journal of fish biology》2020,97(5):1507-1519
Seasonal prey bursts are important for the life cycles and energy budgets of many predators. This study documents the diet and, especially, the importance of the ephemeral occurrence of capelin as prey for Atlantic cod (Gadus morhua) in Godthaabsfjord, west Greenland, over an annual cycle. The cod showed clear differences in diet composition on the 11 sampling dates resulting in a spring–summer, late summer–autumn and winter cluster. Moreover, a single sampling date, 12 May, was defined by cod gorge feeding on spawning capelin, which led to average stomach contents 4.3 times higher than the average for the remaining sampling dates. Changes in nitrogen stable isotope values from 22 April to 7 July in cod liver and muscle tissue were used to calculate the consumption of capelin. Based on this, the consumption of capelin varied between 538 and 658 g wet weight for a 1.3 kg cod. Using published consumption/biomass estimates and observed growth rates, the capelin intake corresponds to 10.1%–33.3% of the annual food consumption and accounts for 28.1%–34.5% of the annual growth of the cod. The present study documents the omnivorous feeding mode of Atlantic cod but highlights the utilization and importance of ephemeral prey bursts for the annual energy budget of the cod. It is hypothesized that access to capelin is critical for the postspawning recovery of Godthaabsfjord cod. 相似文献
3.
Diana Catarino Sergio Stefanni Filipe M. Porteiro Alexandra Rosa Eva Giacomello 《Journal of fish biology》2021,99(1):253-257
The pencil cardinal Epigonus denticulatus is a small deep-water fish inhabiting continental slopes usually between 300 and 600 m depth. We report the first record of E. denticulatus in the Azores archipelago, where one specimen was found floating by fisherman off Faial island. Meristic and morphometric characters are in accordance with those reported for the species and molecular analyses further supported species identity. The record of E. denticulatus as a native species in the Azores increases the number of Epigonus species in the region to a total of three. 相似文献
4.
Maturity, oocyte dynamics and fecundity of the roundnose grenadier from the Rockall Trough 总被引：1，自引：0，他引：1
The reproductive biology of roundnose grenadier Coryphaenoides rupestris was investigated against a background of increasing commercial exploitation. Samples were taken from surveys carried out in Rockall Trough between 1993 and 1995. An eight-point maturity scale was developed based on both visual inspection of the ovaries and histological screening. The various stages of development of roundnose grenadier oocytes were described and the relative proportion of oocyte types and their respective size range in each maturity stage were investigated. The dynamic organization of the ovary indicated a determinate maturation cycle in this species. Population spawning appears to be prolonged, extending from July to at least November. However, data were insufficient to clarify individual spawning duration. The potential fecundity of 29 mature fish ranged from 11 083-55 175 (63-95 cm total length). The results were very similar to previous values from the North Atlantic. The reproductive strategy of the roundnose grenadier is discussed in the light of the current commercial exploitation of the Species. 相似文献
5.
A compilation of experimental animal data shows that neither delta13C(collagen) nor delta13C(apatite) nor Delta13C(CO-AP) indicate diagnostic reconstructions of diet, diet energy and diet protein. In contrast, plots of delta13C(collagen) against delta13C(apatite) provide a model of three regression lines (C3, C4, and marine diet protein) where position on each line indicates the energy source (C3, C4, or mixed). Neither body size nor trophic position appears to affect these relationships. Modern free-ranging, terrestrial fauna do not fit the model perhaps because they, unlike the experimental fauna, mainly use fermentation rather than digestion during energy metabolism. Archaeological humans fall as expected based on associated floral and faunal evidence. Foraging people plot at positions expected from associated C3 fauna and plants. Those from Cahokia plot, as expected, from associated deer, nuts, and maize whereas people from nearby smaller sites plot in positions consistent with eating more fish. Agriculturists from Ontario and Grasshopper Pueblo plot consistent with dependence on fish by the former and on turkeys by the latter. In Tierra del Fuego, people from interior regions ate more terrestrial fauna, as suggested by ethnohistoric reports, than did people from the coast. In the Southwestern Cape in South Africa individuals late in the sequence have pure C3 diets whereas ones early in the sequence ate marine protein as suggested by independent archaeological evidence. People on San Nicolas Island depended on C4 plants in contrast to other islands off California's coast. This simple model provides more detailed and precise dietary information than do individual isotopic measures. 相似文献
6.
Man's biological evolution, state of health and lifestyle are closely associated with dietary changes. The methods for acquiring
useful information on the diet of our ancestors are an important aspect of anthropological research; hence it was retained
interesting to apply the oligoelement and isotopic techniques in parallel on the same sample, in order to compare the two
methodologies, construct a complete nutritional picture, and compare the analytical results with the ancient literary sources
and with the findings from archaeological excavations. 相似文献
7.
Helena C. Serrano Cristina Antunes Manuel J. Pinto Cristina M guas Maria Am lia Martins-Lou o Cristina Branquinho 《Journal of Plant Ecology》2015,8(1):41
Aims The Inclusive Niche Hypothesis has not been validated for plants using ecophysiological performance. The few experiments have measured growth and competition but not the physiological response of plants. A metallophyte plant that hyperaccumulates aluminium (Al), Plantago almogravensis, showed a defined spatial distribution by occurring mostly on vegetation gaps associated with metalliferous areas (geochemical islands). This case was used to determine, in situ, whether the Inclusive Niche Hypothesis was suitable to explain the extent of the species realized niche.Methods The vegetation associated with P. almogravensis geochemical islands in the SW coast of Portugal was mapped. The biotic (neighbouring plants) and abiotic (edaphic) components of the niche were correlated with parameters of the plant's ecological and physiological performances (plant density and cover; leaf C and N concentration and isotopic composition; growth). The results were obtained using image analysis, abundance and morphological measures, isotopic signatures and chemical composition.Important findings The species showed better physiological performance where its ecological performance was lower due to trade-offs with environmental constraints. The species' realized niche was mostly limited by shrub competition and soil Al-toxicity. These limits contribute to explain the rarity status of the species: the species has a poor capacity to compete but, due to an enhanced Al-tolerance and Al-hyperaccumulator trait, has the ability to find refuge in geochemical islands that are too harsh for most other species. This work, based on ecophysiological field studies, provides support for the Inclusive Niche Hypothesis relating to plant species. 相似文献
8.
Brianne Kelly Hugues P. Benoît Gerald Chaput Ross A. Jones Michael Power 《Journal of fish biology》2019,94(1):40-52
The diet of repeat-spawner Atlantic salmon Salmo salar was investigated using carbon and nitrogen stable-isotope values from the outer growth band of scales, which reflect the fish's consumption and growth during their most recent marine phase. Isotope values for S. salar displaying different spawning strategies were compared between and within the Miramichi and Nashwaak Rivers, New Brunswick, Canada and a Bayesian mixing model was used to infer dietary contributions from potential prey items. Significant differences in the stable-isotope values were found among spawning strategies and between rivers, indicating differences in diet and feeding area, consistent with hypotheses. Bayesian mixing model results inferred the main prey items consumed during marine feeding by S. salar to consist of hyperiid amphipods and capelin Mallotus villosus for repeat alternate spawners from both rivers, sandlance Ammodytes sp. for repeat consecutive spawners from the Miramichi River and amphipods for repeat consecutive spawners from the Nashwaak River. These results demonstrate the diversity of feeding tactics among S. salar spawning strategies from the same river and between populations from different rivers. Accounting for differences in prey availability and the subsequent impact on S. salar diet and spawner return rates (i.e., marine survival) will facilitate the application of ecosystem-based management practices, such as ensuring that fisheries for forage species do not indirectly adversely affect S. salar return rates. 相似文献
9.
10.
Márcio S. Araújo R. Brian Langerhans Sean T. Giery Craig A. Layman 《Ecology and evolution》2014,4(16):3298-3308
One consequence of human‐driven habitat degradation in general, and habitat fragmentation in particular, is loss of biodiversity. An often‐underappreciated aspect of habitat fragmentation relates to changes in the ecology of species that persist in altered habitats. In Bahamian wetlands, ecosystem fragmentation causes disruption of hydrological connectivity between inland fragmented wetlands and adjacent marine areas, with the consequent loss of marine piscivores from fragmented sections. We took advantage of this environmental gradient to investigate effects of ecosystem fragmentation on patterns of resource use in the livebearing fish Gambusia hubbsi (Family Poeciliidae), using both population‐ and individual‐level perspectives. We show that fragmentation‐induced release from predation led to increased G. hubbsi population densities, which consequently led to lower mean growth rates, likely as a result of higher intraspecific competition for food. This was accompanied by a broadening of dietary niches via increased interindividual diet variation, suggesting a negative effect of predation and a positive effect of intraspecific competition on the degree of diet variation in natural populations. Our results therefore indicate that habitat fragmentation can greatly impact the ecology of resilient populations, with potentially important ecological and evolutionary implications. 相似文献
11.
The diet and habitat of eight danionin species ( Danio and Devario ) from 18 sites in India and Thailand are reported. At every site, habitat characteristics, including pH, light penetration, water temperature, current speed, stream dimensions, canopy cover and substratum type, were recorded. Danionins were found primarily in warm (24–35° C), moving water of moderate clarity and pH (6·6–8·2) and there were significant differences among species in water temperature, pH and current speed. Deep-bodied Devario species were generally associated with faster water currents than more slender-bodied Danio species. Gut content analyses of 327 individuals representing 17 populations showed that insects were the primary food resource for the eight Danio and Devario species. Crustaceans, fish scales, algae and detritus were also important supplements for particular species. Stable isotope data from syntopic species indicated long-term differences in consumption of terrestrial v. aquatic insects in one of two population pairs. 相似文献
12.
《Ethology, Ecology and Evolution》2012,24(3):215-223
Multiple stable isotope analysis was used to investigate the diet of the common dormouse Muscardinus avellanarius in a mixed Mediterranean forest. δ13C and δ15N values of dormouse tissues compared to those of the vegetal and animal sources available in the area showed that the isotopic composition of both adult and juvenile M. avellanarius could be explained by a mixture of vegetal and animal organic matter. The isotopic composition of the assimilated nitrogen was mostly explained by the organic matter from flora. Among the vegetal components, flowers of Fagus silvatica, Quercus robur, and the rarer Crataegus oxyacantha, berries of Ilex aquifolium and acorns of Q. robur were found in the adult diet, while juveniles relied mainly on flowers of F. silvatica and acorns of Q. robur. Organic matter from eggs of passerines (Parus caeruleus and P. major) sharing nest-boxes affected the carbon isotopic signals in the assimilated fraction. The common dormouse in the mixed holly forests of the northern Sicily feeds primarily on the vegetal species which are abundant in its habitat. However, the diet of this small arboreal mammal cannot be fully characterised without considering the contribution of animal organic matter represented by bird eggs. 相似文献
13.
The diet of the dusky grouper Epinephelus marginatus , from the Balearic Islands, western Mediterranean, consisted primarily of crustaceans, molluscs and fishes, but diet composition varied with body size. The smaller dusky groupers (<300 mm L T ) fed primarily on crustaceans, and particularly on brachyurans, which accounted for 46% of the prey identified. As dusky groupers grew, cephalopods became increasingly important and constituted 10 to 40% of the prey identified in subadult and adult specimens. The largest dusky groupers fed primarily on fishes that represented 40·9% of prey identified. These shifts in diet were accompanied by a positive selection of increasingly large prey and by an expansion of trophic niche. δ 15 N values of dusky grouper white muscle ranged from 8·8 to 13·1% and 71% of the variation in δ 15 N was explained by differences in dusky grouper size. δ 13 C values ranged from – 17·9 to – 15·9%, and no significant body size effect on δ 13 C was detected. Stomach content and 13 C values indicated that from 1 year old, the diet of E. marginatus was based on the benthic food web. The enrichment in δ 15 N registered from juvenile to large males was c . 3·8%. Overall, there was good agreement between gut content and stable isotope data indicating that the latter may be useful as a tool in trophic studies in marine protected areas where sampling for fishes is not allowed. 相似文献
14.
T L Dupras H P Schwarcz S I Fairgrieve 《American journal of physical anthropology》2001,115(3):204-212
Current knowledge of infant feeding and weaning practices during the Roman period in Egypt is limited to scanty documentary and iconographic evidence. Stable nitrogen and carbon isotope analysis provides another avenue to explore this question. A sample of 49 infant and juvenile human skeletal remains from the Kellis 2 cemetery in the Dakhleh Oasis, Egypt, was used to determine patterns of infant feeding and weaning. delta(15)N values indicate that supplementary foods were introduced at around 6 months of age, and that weaning was complete by 3 years of age. By 6 months of age, delta(13)C values become increasingly enriched over adult values, and reach peak enrichment at approximately 1.5 years of age. Beyond this age, delta(13)C gradually declines to approach adult values. This enrichment in infant delta(13)C values is indicative of consumption of (13)C-enriched supplementary foods. Based on isotopic study of faunal and botanical remains from the ancient village of Kellis, we conclude that at approximately 6 months of age, infants were fed milk of goat and/or cow. 相似文献
15.
Anthony J. Orr Seth D. Newsome Jeffrey L. Laake Glenn R. VanBlaricom Robert L. DeLong 《Marine Mammal Science》2012,28(4):714-732
We used stable carbon (δ13C) and nitrogen (δ15N) isotopes to examine ontogenetic dietary changes in 289 California sea lions (Zalophus californianus) at San Miguel Island, California during 2004–2007. Tissues analyzed included fur, red blood cells, plasma, and serum. For all tissues, pups had higher δ15N values and lower δ13C values compared to adults, which indicated that pups were feeding higher trophically than older conspecifics and on a lipid‐rich milk diet prior to weaning. Yearling δ15N values were slightly lower than pup or nearly indistinguishable from adult values depending on the tissue analyzed, indicating a dietary shift from maternal dependency to independent foraging. Juveniles (2–4 yr) and adults (>4 yr) had similar δ15N values indicating they fed at a similar trophic level. There did not appear to be a pronounced dietary shift in δ13C values. However, δ13C values integrated with telemetry data indicated that postweaned individuals fed in similar foraging areas. Dietary changes during early life stages may be due to differences in physiology, morphology, experience, or energetic requirements; however, young animals are able to attain the skills needed to consume adult prey types near the end of their second year of life. 相似文献
16.
FERNANDO AMOR IRENE VILLALTA CLAUDIE DOUMS ELENA ANGULO STEPHANE CAUT SARA CASTRO MICHAEL J. JOWERS XIM CERDÁ RAPHAËL BOULAY 《Ecological Entomology》2016,41(6):660-667
1. In many ant species, caste differentiation stems from trophic differences at the larval stage. Adult workers that feed larvae have great control over the allocation of colony resources to growth (production of workers) versus reproduction (production of queens). However, larval caste fate may also be constrained very early on through direct genetic effects or non‐genetic maternal effects. 2. Here, we combined isotopic and genetic analyses to study the developmental origin of queens and workers in a desert‐dwelling ant, Cataglyphis tartessica (Amor & Ortega, 2014). Queens do not found new colonies alone but rather disperse with workers. As the latter are always wingless, selection pressures on specific queen traits such as flight ability have become relaxed. Though the phylogenetically related species, C. emmae (Forel, 1909) only produces winged queens much larger than workers, C. tartessica produces two types of small queens relative to workers: brachypterous (short‐winged) queens and permanently apterous ergatoid (wingless and worker‐like) queens. 3. Upon emergence, workers and ergatoids have similar δ15N isotopic values, which were lower than those of brachypters, suggesting the latter are fed more protein as larvae. Microsatellite analyses indicated that: (i) colonies are mostly monogynous and monandrous; (ii) both ergatoids and brachypters are equally related to workers; and (iii) in the few polyandrous colonies, patrilines were evenly represented across workers, brachypters and ergatoids. 4. Overall, there was no evidence of genetic caste determination. We suggest that, in contrast to brachypters, ergatoids are selfish individuals that escape the nutritional castration carried out by workers and develop into queens in spite of the colony's collective interests. 相似文献
17.
18.
D. Mendiola † P. Alvarez U. Cotano A. Martínezde Murguía‡ 《Journal of fish biology》2007,70(3):911-933
The early development, growth and morphological changes of mackerel Scomber scombrus were investigated at different incubation temperatures (8, 10, 13, 15 and 18° C). Details on the early life history are illustrated with special reference to morphological transformations. Culture techniques to rear larval mackerel stages are described using laboratory cultured foods. Artificially fertilized eggs were hatched after 80·6 h at 18·4° C and 256·8 h at 8·7° C. The standard length ( L S ) of the individuals at first feeding was 4·71 ± 0·18 mm. Four mortality critical periods and cannibalistic behaviour were identified. A maximum average larval size of 37·5 ± 4·41 mm L S was attained 30 days post-hatch (dph) at 18·4° C. Development and growth were affected significantly by temperature during both endogenous and exogenous feeding periods. Larvae grew more rapidly at high, than at low temperatures. Daily specific growth rate (in mass) ranged from 2·4% at 10·6° C to 16·9% at 18·4° C. Likewise, average growth rate (in length) ranged from 0·05 mm day−1 at 8·4° C to 0·37 mm day−1 at 18·4° C. The allometric relationship of L S , with several body measurements was not affected by temperature. Comparison with larvae collected in the Bay of Biscay did not show any significant difference in the dry mass and L S relationship; conversely, the growth rate in length differed significantly between both laboratory and field conditions. The trends observed in the laboratory are described in relation to some aspects of the year-class strength regulation. 相似文献
19.
Brandon M. Strange Russell K. Monson Paul Szejner Jim Ehleringer Jia Hu 《Global Change Biology》2023,29(15):4354-4367
The US Southwest has been entrenched in a two-decade-long megadrought (MD), the most severe since 800 CE, which threatens the long-term vitality and persistence of regional montane forests. Here, we report that in the face of record low winter precipitation and increasing atmospheric aridity, seasonal activity of the North American Monsoon (NAM) climate system brings sufficient precipitation during the height of the summer to alleviate extreme tree water stress. We studied seasonally resolved, tree-ring stable carbon isotope ratios across a 57-year time series (1960–2017) in 17 Ponderosa pine forests distributed across the NAM geographic domain. Our study focused on the isotope dynamics of latewood (LW), which is produced in association with NAM rains. During the MD, populations growing within the core region of the NAM operated at lower intrinsic and higher evaporative water-use efficiencies (WUEi and WUEE, respectively), compared to populations growing in the periphery of the NAM domain, indicating less physiological water stress in those populations with access to NAM moisture. The disparities in water-use efficiencies in periphery populations are due to a higher atmospheric vapor pressure deficit (VPD) and reduced access to summer soil moisture. The buffering advantage of the NAM, however, is weakening. We observed that since the MD, the relationship between WUEi and WUEE in forests within the core NAM domain is shifting toward a drought response similar to forests on the periphery of the NAM. After correcting for past increases in the atmospheric CO2 concentration, we were able to isolate the LW time-series responses to climate alone. This showed that the shift in the relation between WUEi and WUEE was driven by the extreme increases in MD-associated VPD, with little advantageous influence on stomatal conductance from increases in atmospheric CO2 concentration. 相似文献
20.
A. Elgueta J. González D. E. Ruzzante S. J. Walde E. Habit 《Journal of fish biology》2013,82(2):430-443
The length and mass ratio, diet and isotopic composition of Aplochiton zebra and Aplochiton taeniatus inhabiting a Salmo trutta‐invaded and a S. trutta‐free lake in southern Patagonia were compared. Results indicate that S. trutta exercises important trophic interference over A. zebra and A. taeniatus, causing changes in their dietary composition by reducing the consumption of winged Diptera through changes in feeding behaviours that involve jumping out of the water. This effect is significantly higher in A. zebra than in A. taeniatus a species that has a highly specialized diet. The dietary changes of A. zebra and A. taeniatus in sympatry with S. trutta lead to an impoverishment of their isotopic nitrogen signals (δ15N), suggesting a reduction of their trophic position. In the case of A. zebra, this translates into a significant decrease in its body condition factor. Such interference could lead to a population decline of this species and would explain the current distribution range decline and allopatry with S. trutta in fluvial systems. 相似文献