Significant Differences In Diet Composition Research Articles

The influence of chronotype on temporal patterns of eating and diet composition in shift and non-shift workers

When and what you eat can be linked to circadian preference (i.e., chronotype) and occupation (e.g., shift worker). Evening chronotypes, with a later circadian preference, tend to have meals later, distribute energy intake toward the end of the day(1), and more unhealthy eating habits than morning chronotypes(2); whereas night shift work is associated with later mealtimes and poor diet quality as a result of circadian disruption due to their work(3). What is unclear is whether chronotype influences the occupation-induced dietary patterns observed in shift workers. This study aimed to investigate associations between chronotype, temporal patterns of eating and diet composition in shift and non-shift workers. Adults from shift (SW) and non-shift (N-SW) populations were recruited. A Chrononutrition Questionnaire captured chronotype, duration of eating window (DEW), time of first eating occasion (FEO) and last eating occasion (LEO) while diet composition (energy, protein, total fat, saturated fat, carbohydrate, fibre, alcohol) was extracted from 7-day food diaries. Associations between chronotype and DEW/FEO/LEO, and between DEW/FEO/LEO and diet composition were determined by Spearman Rank Coefficients. 95 participants were enrolled (N-SW: n = 39; SW: n = 56); predominantly female (71%), morning chronotype (37%), on average 40.46 ± 15.08 years with BMI of 27.04 ± 5.77kg/m2. 84 returned food diaries. Later chronotype was positively associated with later times of FEO (N-SW: r = ,50, SW: r = ,69) and LEO (N-SW: r = ,63, SW: r = ,54) on free (non-work) days (p≤.002), and longer DEW (r = ,42) and later LEO (r = ,60) on workdays for non-shift workers (p<.01). However, there were no significant differences in diet composition by day/shift type between chronotypes across the study population. On afternoon shifts, longer DEW was associated with greater energy (r = ,60) and total fat intake (r = ,60) and later LEO with greater alcohol intake (r = ,59) (p<.05). On night shifts, a longer DEW was associated with lower alcohol intake (r=-.45, p<.05). Amongst non-shift workers, later FEO was associated with lower fibre intake on workdays (r=-.58, p<.001). Additionally, non-shift workers who were later chronotypes had later LEO, which on workdays associated with lower fibre (r=-.45) and alcohol intake (r=-.43); and on work-free days, associated with lower alcohol intake (r=-.45) (p<.05). Not surprisingly, evening chronotypes across the study population had longer and/or later eating windows on work-free days (i.e., free of constraints), as did non-shift workers on workdays, while the influence of chronotype on DEW, FEO, and LEO across shifts were less clear. Hence, for shift workers, occupation appeared to be a greater driver of temporal eating patterns than chronotype. Additionally, later eating times of evening chronotypes was not associated with negative diet composition. The exception was lower fibre intake amongst non-shift workers; but regardless of chronotype, shift workers may benefit from having a shorter and earlier DEW on afternoon shifts to minimise energy, fat, and alcohol intake.

Chick diet in UK Little Terns Sternula albifrons

ABSTRACT Capsule We studied the diet of Little Tern chicks in the UK using new data collected as part of the EU LIFE-funded Little Tern Recovery Project (2014–2018) (the LIFE Project), which shows that, despite a wide variety of prey items being recorded, diet at UK colonies is dominated by two types of lipid-rich marine fish: sandeel Ammodytes spp. and clupeid species (Atlantic Herring Clupea harengus and European Sprat Sprattus sprattus). Aims To analyse data on the diet of Little Tern chicks from the LIFE Project and assess what additional insight these provide in comparison to the findings in previous literature. Methods Timed chick-feeding observations were made at 12 English and Welsh Little Tern colonies between 2014 and 2018 and compared to descriptions of chick diet from other UK studies (published and unpublished). Results Chick diet data from the LIFE Project were dominated by lipid-rich marine fish, principally sandeels and clupeid species (82% of all recorded prey items). Adult Little Terns feeding chicks with crustaceans or other invertebrates were recorded at 75% of colonies, but there was no evidence that these routinely made up a substantial proportion of chick diet. We found no significant inter-annual differences in diet composition between individual colonies. However, analysis of records of chick diet over a longer time series (Long Nanny colony in Northumberland, with data available for 17 of the years between 1998 and 2018) showed some significant differences in diet composition between years. Conclusion Although Little Terns are generalist feeders, 82% of the prey diet consisted of two prey types: sandeels and clupeids. This may leave existing UK Little Tern colonies vulnerable to any future climate change impacts affecting either the distribution or nutritional quality of their main prey species.

Diet Analysis of the Amur Sleeper (Perccottus glenii) from the Danube River Drainage Channel (Serbia)

The stomach content of 277 Amur sleeper individuals has been analyzed to present its feeding habits. Fish were sampled using electrofishing from July to November 2017 in the Danube River drainage channel near Veliko Gradište (Serbia). Fish age was estimated by otoliths examination. Ingested prey organisms were identified to the lowest reliable taxonomic level. The biotic indices: vacuity index (VI), frequency of occurrence (F), abundance (Cn), index of importance (PV), Shannon`s diversity index (H`), and equitability index (Eh) were calculated. A total of 18 prey categories and 1144 individual prey were identified in the fish diet, dominantly aquatic macroinvertebrates. There were no significant difference in diet composition between sampling months as well as 0+, 1+, and 2+ age groups (both 3+ and 4+ had one individual). Only eight individuals were found with empty intestines, thus VI was low (2.9). In average, each fish had 4.1 prey items in their intestines. For whole sample, H′ was 1.84 and Eh was 0.64. Trichoptera, Ephemeroptera, and Gastropoda were the most frequent, dominant, and abundant. The greatest diversity of prey items was recorded for fish sampled in October as well as for 2+ individuals, and the lowest for fish from August and 0+ individuals.

Diet composition, niche overlap and partitioning of five sympatric rhinolophid bats in Southwestern China during summer

Understanding trophic niche differentiation is critical for exploring interspecific competition and stable coexistence among morphologically similar sympatric species. Bats are an ideal model for studying trophic niche differentiation among species because of their high taxonomic and ecological diversities, as well as their special life history traits. Although many factors can affect bat trophic niches, few studies have combined multiple factors to investigate the influences on bat trophic niches. In this study, we analyzed the summer diet and potential influencing factors of five sympatric rhinolophid bats in southwestern China: Rhinolophus macrotis, Rhinolophus osgoodi, Rhinolophus ferrumequinum, Rhinolophus affinis, and Rhinolophus pusillus. All five species mainly fed on Lepidopteran and Dipteran insects, with a large trophic niche breadth for each species and a low degree of dietary overlap. With the exception of R. affinis and R. pusillus, significant differences in diet composition were detected among species, which indicated relatively low interspecific competition. Canonical correspondence analysis showed that both echolocation calls and body size significantly affected interspecific diet differentiation, while wing morphology and bite force had relatively weak effects. This study suggests that the combined effects of multiple factors may drive trophic niche differentiation among five rhinolophid bat species in the study area.

Relative abundance and size composition of prey in the common minke whale diet in selected areas of the northeastern Atlantic during 2000-04

A total of 210 common minke whales (Balaenoptera acutorostrata) were sampled in five different areas in the northeastern Atlantic during May-June 2000-04. Analysis of forestomach contents revealed a relatively mixed diet at the population level, whereas on an individual level, each whale had fed upon mainly one species. There were significant differences in diet composition between areas and some differences between years. The importance of krill in the Barents Sea increased with latitude and krill dominated the Spitsbergen diet. Capelin dominated the diet around Bear Island and contributed considerably to the diet along the coast of northern Norway. In the latter area, herring and haddock were also a great part of the diet. The diet in the Norwegian Sea consisted of mainly mature herring, while the diet in the North Sea was dominated by sand eels and mackerel. The minke whales were found to feed on a wide range of prey sizes, apparently determined by the availability of different size classes.

Preliminary Investigation of Microbiome and Dietary Differences in Patients with Phenylketonuria on Enzyme Substitution Therapy Compared to Traditional Therapies

BackgroundPhenylketonuria (PKU) is an inborn error of metabolism that impairs the function of the enzyme phenylalanine hydroxylase. Historical treatment includes limiting dietary phenylalanine (Phe) consumption while supplementing with medical food; however, this treatment has been associated with complications, such as nutritional deficiencies and disruptions in the gut microbiota. ObjectiveThe study aim was to compare dietary and gut microbiome differences between adult patients on a traditional PKU diet with those receiving the enzyme substitution therapy Palynziq on a liberalized diet while controlling blood Phe levels to <600 μmol/L (to convert to mg/dL divide by 60.5). DesignA cross-sectional study was conducted comparing patients on a traditional Phe-restricted diet with patients receiving Palynziq eating a liberalized diet. Participants/settingSix patients eating a traditional Phe-restricted diet with medical food and 6 patients on Palynziq eating a liberalized diet without medical food intake for more than 3 years were selected from the University of Kentucky Metabolic Clinic from August to December 2019. Main outcome measuresNutrient intake from 3-day diet records and fecal microbiome taxonomic abundances were analyzed. Statistical analysisMann-Whitney U tests were used for dietary data analysis. Differential abundance analysis for microbiome taxa and pathway data was done using DESeq2 analysis. ResultsDietary data showed patients receiving Palynziq consumed a lower percent of kilocalories from total protein and lower amounts of most micronutrients, but consumed greater amounts of intact protein and cholesterol (P < .05). Microbiome data revealed a greater abundance of the phylum Verrucomicrobia and genus Lachnobacterium in the Traditional group and a greater abundance of the genus Prevotella in the Palynziq group (P < .05). Pathway analysis depicted greater enrichment in carotenoid and amino acid metabolism pathways in the Traditional group (P < .05). Protein (% kcal), dietary fiber (g), fat (% kcal), linolenic acid (% Dietary Reference Intakes), and age were correlated with the underlying microbial community structure for both groups combined. ConclusionsPatients with PKU treated with Palynziq on a liberalized diet manifest significant differences in diet composition compared with those treated with traditional Phe-restricted diets. Several of these dietary differences may affect the microbiome architecture.

Home range, habitat selection, density, and diet of golden jackals in the Eastern Plains Landscape, Cambodia.

We used radiocollars and GPS collars to determine the movements and habitat selection of golden jackals (Canis aureus) in a seasonally dry deciduous forest with no human settlements in eastern Cambodia. We also collected and analyzed 147 scats from jackals to determine their seasonal diet and prey selection. The mean (± SE) annual size of home-range ranges (47.1 ± 2.5 km2; n = 4), which were mutually exclusive between mated pairs, was considerably larger than that previously reported for this species, resulting in an extremely low density (0.01 jackal/km2). The unusually large home ranges and low density probably were due to the harsh dry season when most understory vegetation is burned and nearly all waterholes dry up, thereby causing a large seasonal decline in the availability of small vertebrate prey. Resident groups consisted of an alpha pair, but no betas, and were situated only in areas not occupied by leopards (Panthera pardus) and dholes (Cuon alpinus). Jackals avoided dense forests and streams, and had a strong selection for dirt roads, possibly to avoid larger predators. Overall the jackal diet was diverse, with at least 16 prey items identified, and there was no significant difference in diet composition between the cool-dry and hot-dry seasons. Scat analysis showed that the main food items consumed by jackals were processional termites (Hospitalitermes spp.; 26% biomass consumed), followed by wild pig (Sus scrofa; 20%), muntjac (Muntiacus vaginalis; 20%), and civets (17%). Compared to available biomass, jackals were not random in their consumption of ungulates because muntjac were selectively consumed over larger ungulate species. Dietary overlap with dholes and leopards was relatively low, and consumption patterns indicated jackals were preying on ungulates rather than scavenging from kills of larger carnivores. Our results showed that the jackal is an extremely adaptable and opportunistic species that exhibits unique behaviors to survive in an extreme environment near the edge of its distribution.

基于高通量测序的象山港海域黑鲷(Acanthopagrus schlegelii)食性分析

PDF HTML阅读 XML下载 导出引用 引用提醒 基于高通量测序的象山港海域黑鲷(Acanthopagrus schlegelii)食性分析 DOI: 10.5846/stxb201911022308 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 中国水产科学研究院基本科研业务费（2019ZD1102）；国家公益性行业（农业）科研专项经费项目（201303047）；上海市自然科学基金项目（17ZR1439500） Diet composition and feeding habits of black sea bream (Acanthopagrus schlegelii) in Xiangshan Bay based on high-throughput sequencing Author: Affiliation: Fund Project: the Special Scientifi c Research Funds for Central Non-profi t Institutes, Chinese Academy of Fishery Sciences (project no.2019ZD1102)；National Special Research Fund for Non-Profit Sector (Agriculture)(project no.201303047)；the Natural Science Foundation of Shanghai City (project no. 17ZR1439500) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:选取象山港黑鲷个体为研究对象，以18S rDNA为靶标，利用Illumina Miseq高通量测序方法研究黑鲷饵料生物组成特征，分析不同龄组黑鲷的食性异同。通过序列比对，共在黑鲷胃含物中鉴定出41个属中的62种饵料生物，分属9个门，其中节肢动物门（Arthropoda）、绿藻门（Chlorophyta）和软体动物门（Mollusca）是黑鲷饵料生物的优势组成门类。从饵料生物相对丰度和出现频率上分析，石莼（Ulva lactuca）、熊本牡蛎（Crassostrea sikamea）、胸刺水蚤（Centropages hamatus）、日本蟳（Charybdis japonica）、毛蚶（Scapharca subcrenata）和褐菖鲉（Sebastiscus marmoratus）是黑鲷的优势饵料物种，所占饵料生物总相对丰度的比重达60.90%。相似性分析检验（ANOSIM）结果显示：1至4龄黑鲷个体的饵料生物组成不存在显著性差异。与传统食性分析方法相比，高通量测序法在黑鲷饵料生物检测灵敏性上显现了较为明显的优势，保障黑鲷等重要物种的种群稳定对于该海域具有重要的生态和经济意义。 Abstract:Xiangshan Bay is a semi-closed bay in the central coast of Zhejiang Province, China. It is also a centralized distribution area of various fishery resources, and many economic fish species breeding there every year. However, due to long-term overfishing, ocean development and environmental pollution, deterioration of ecological environment was found in this sea area, which also caused the increasingly recession of local fishery resources. In recent years, after fishery resources conservation, fishery resources in this water have been restored. It also provides a good habitat for reef-loving species such as the black sea bream Acanthopagrus schlegelii. A. schlegelii is an important fish species targeted by recreational and commercial fisheries in Xiangshan Bay. Maintaining population stability of this species is economically and ecologically important for the embayment. Knowledge of the feeding ecology is of great value for conservation strategies, as it is thoroughly linked to subjects such as resource partitioning, habitat preferences, prey selection, predation, competition and energy transfer within and between ecosystems. However, relatively little work has been done on this aspect in A. schlegelii. In this study, 21 individuals of A. schlegelii were collected in Xiangshan Bay, and diet composition and feeding habits were analyzed by high-throughput sequencing methods targeting 18S rDNA gene. By Illumina high-throughput sequencing, 913,254 target fragments with length of about 420 bp were obtained. The minimum sequence number of samples was 30,826, while the maximum one was 52,374. A total of 554 OTU (operational taxonomic units) were obtained from 21 samples after clustering. And 62 species in 9 categories were identified in the stomach contents of this species after sequence alignment, in which Mollusca, Arthropoda and Chlorophyta exhibited the highest abundance, followed by Chordata, Platyhelminthes, Bacillariophyta and Annelida. Ulva lactuca, Crassostrea sikamea, Centropages hamatus, Charybdis japonica, Scapharca subcrenata and Sebastiscus marmoratus were dominant prey items for A. schlegelii in Xiangshan Bay. The above prey items accounted for 60.90% of the total abundance of gastric contents. In addition, a number of species, including Caprella scaura, Oithona sp., Melosira sp., Cyclotella sp., Chlorella stigmatophora, Picochlorum sp., Torodinium robustum, and Chromadorina sp., with quite low abundance were also detected. These prey items were distributed in different ecological communities, including macroalgae, shellfish, zooplankton, phytoplankton, macrozoobenthos, fish, and crab. These data suggests that A. schlegelii is a relatively large omnivorous consumer. Result from the analysis of similarities (ANOSIM) showed no significant difference in diet composition for fish among different age groups. This indicates that A. schlegelii did not alter feeding habits after 1 year old. Considering the limited sample size, however, further studies are still needed to address this conclusion. Compared with the traditional analysis methods, high-throughput sequencing has the characteristics of less sample demand, less workload, and more species detection. Meanwhile, due to its sensitivity, some species with low abundance that could not be found by traditional methods can also be detected. Hence, high-throughput sequencing technology has obvious advantages in fish diet studies and can provide strong support for marine organisms feeding and ecological studies. 参考文献 相似文献 引证文献

The diet of the anchovy Engraulis encrasicolus (Linnaeus, 1758) during the spawning season in the eastern Adriatic Sea

The objective of this study was to determine, both quantitatively and qualitatively, the variability in the diet of the anchovy, Engraulis encrasicolus,during its spawning period. Samples were obtained from commercial purse seine catches (April 2014 – September 2016) from coastal and offshore fishing areas of different trophic states and zooplankton composition over the eastern Adriatic Sea. In general, decapod larvae comprise the main source of diet during the anchovies’ spawning period in terms of frequency and abundance, followed by calanoid copepods. The main copepod prey that was identified for anchovy along the eastern Adriatic coast was calanoid Temora stylifera, followed by Oncaeid copepods and Corycaeidae. Although no significant differences in diet composition regarding the anchovy’s size was observed, the contribution of copepods decreased in larger individuals, and were gradually substituted by large crustaceans - decapods, euphausiids, mysids and amphipods. However, a significant difference in prey composition between coastal and offshore areas was observed (global R=0.164, p&amp;lt;0.05). Beside adult copepods, offshore water anchovy fed mainly on decapod larvae and their megalopa stage, and amphipods. In the stomach of the fish caught in the coastal waters, higher contributions of euphausiids, mysids and fish eggs were observed. Prey diversity was greater in the stomach of specimens caught offshore (H’=0.59) than in the coastal Adriatic waters (H’=0.40).

Diet of Natalus mexicanus (Chiroptera, Natalidae) in a semi-evergreen forest in Oaxaca, Mexico

We investigated the diet composition of Natalus mexicanus in a semi-evergreen forest in the state of Oaxaca, in the southeast of Mexico, using fecal analysis. The diet was composed of eight arthropod orders, the most abundant and important preys being members of the orders Diptera, Coleoptera, Hemiptera, and Hymenoptera. We did not observe significant differences in diet composition between males and females or in proportions consumed by the bats and those obtained through collections with light traps. In the study area, N. mexicanus is a species with a generalist opportunist diet.

Stomach content and stable isotopes reveal an ontogenetic dietary shift of young-of-the-year scalloped hammerhead sharks (Sphyrna lewini) inhabiting coastal nursery areas

Sphyrna lewini is a placental viviparous shark that uses coastal nursery areas in Jalisco, Mexico, where pups stay 4–12 months. Changes in size or swimming speed may be reflected in diet composition. The main objectives of this study were as follows: (1) analyze the differences in trophic ecology of juvenile S. lewini from coastal nursery areas of Jalisco by sex and size, through stomach content and stable isotope analyses; and (2) analyze changes in muscle and liver δ15N and δ13C values with shark size. Samples were collected from the artisanal fishery from September 2013 to December 2016. Three size classes were compared: neonates, stretched total length (STL) ≤ 75 cm, and STL > 75 cm (75–100 cm). Bony fishes were the most important group in all size classes, and the importance of shrimps decreased with STL. Significant differences in diet composition were found between neonates and STL > 75 cm, which showed the lowest niche overlap (0.32). STL ≤ 75 cm showed the largest niche width (0.75). The δ15N muscle and liver values declined with total length, reflecting the maternal isotopic signal. No differences in liver δ13C values were observed among size classes, but larger size class showed higher muscle δ13C values. Both isotope and stomach content analyses classified all sharks as tertiary consumers, but the trophic position (TP) estimated using δ15N was higher in neonates. No significant differences in the diet and TP were observed between sexes. The liver C:N ratio decreased sharply with STL up to 55 cm, from which increased smoothly, reflecting the lipid reserves consumed during their neonatal stage.

Seasonal variation in diet and prey availability in the wall lizard Podarcis vaucheri (Boulenger, 1905) from the Djurdjura Mountains, northern Algeria

ABSTRACTWe studied the composition and seasonal changes in diet and prey selection in the wall lizard Podarcis vaucheri of the Djurdjura Mountains throughout its activity period, from April to October 2014. The analysis of 238 faecal pellets revealed 1 206 prey items distributed in 19 prey categories. The most important prey categories were: Formicidae, Coleoptera, Aranea, Homoptera, and Orthoptera. Significant seasonal variation in the taxonomic composition of the diet and prey availability was found. A significant difference in diet composition was observed between males and females in spring. This lizard species displayed a more diverse dietary spectrum during this period, followed by a slight decrease in summer. However, a severe decrease in the food niche breadth was observed in autumn, resulting in a high consumption of ants. A comparison of diet composition and prey availability showed that lizards exhibited a clear selection of certain prey types, in contrast to what is often suggested for lacertid lizards.

Dietary partitioning promotes the coexistence of planktivorous species on coral reefs.

Theories involving niche diversification to explain high levels of tropical diversity propose that species are more likely to co‐occur if they partition at least one dimension of their ecological niche space. Yet, numerous species appear to have widely overlapping niches based upon broad categorizations of resource use or functional traits. In particular, the extent to which food partitioning contributes to species coexistence in hyperdiverse tropical ecosystems remains unresolved. Here, we use a molecular approach to investigate inter‐ and intraspecific dietary partitioning between two species of damselfish (Dascyllus flavicaudus, Chromis viridis) that commonly co‐occur in branching corals. Species‐level identification of their diverse zooplankton prey revealed significant differences in diet composition between species despite their seemingly similar feeding strategies. Dascyllus exhibited a more diverse diet than Chromis, whereas Chromis tended to select larger prey items. A large calanoid copepod, Labidocera sp., found in low density and higher in the water column during the day, explained more than 19% of the variation in dietary composition between Dascyllus and Chromis. Dascyllus did not significantly shift its diet in the presence of Chromis, which suggests intrinsic differences in feeding behaviour. Finally, prey composition significantly shifted during the ontogeny of both fish species. Our findings show that levels of dietary specialization among coral reef associated species have likely been underestimated, and they underscore the importance of characterizing trophic webs in tropical ecosystems at higher levels of taxonomic resolution. They also suggest that niche redundancy may not be as common as previously thought.

Differences between colonies and chick-rearing stages in Imperial Cormorant (Phalacrocorax atriceps) diet composition: implications for trophic studies and monitoring

ABSTRACT We assessed differences in diet composition between Imperial Cormorants (Phalacrocorax atriceps) breeding at Isla Arce and Isla Vernaci Este, Golfo San Jorge, Argentina. Both colonies are located within the Patagonia Austral marine park, and commercial trawl fisheries operate in adjacent waters, thus knowledge of their food requirement is fundamental to assess potential conflicts and monitor interactions. We obtained stomach samples from 63 adult Imperial Cormorants during the chick-rearing period in 2014: 32 at Isla Arce and 31 at Isla Vernaci Este. We recorded 27 and 30 prey taxa in stomach samples at Isla Arce and Isla Vernaci Este, respectively, and at least 21 were common to both islands. Significant differences in diet composition in terms of importance by mass were found between young and old chick stages at Isla Arce but not at Isla Vernaci Este. Rock cod (Patagonotothen spp.) were dominant at Isla Vernaci Este during both chick stages (75.7% and 86.5%, respectively). At Isla Arce, rock c...

Feeding ecology of the Sicilian pond turtle Emys trinacris (Testudines, Emydidae) influenced by seasons and invasive aliens species

AbstractFeeding ecology of a species is the result of its evolutionary history, biology, physiology and local constraints, such as prey availability, intra‐ and inter‐specific interactions and environmental characteristics. In this study we investigated the still unknown diet of the Sicilian pond turtle, with special emphasis to the relationships with recently introduced alien species in the “Lake Preola and Gorghi Tondi” Nature Reserve (Sicily, Italy). A total of 83 faecal samples were collected in three different periods. Emys trinacris seems an opportunistic and generalist species. The main prey taxa were aquatic invertebrates, including the invasive Procambarus clarkii, while non‐aquatic preys are found sporadically. Plant matter, mainly leaves and roots of aquatic forms, was also found in high frequency with a high occurrence of fruits and seeds in spring. We did not find a significant difference in diet composition within sex and age, while an evident divergence was found between periods and sites. In particular, we noticed a decrease in prey abundance and in food‐niche breadth from pre‐reproductive period to post‐reproductive period. Moreover a very clear difference was found between a site with allochthonous fishes and a site fish‐free, with a more abundant and wide diet spectrum in the last one, as a result of the increased availability of prey. We highlighted the importance to take any possible actions to avoid the spread of fishes in other basins and to study the indirect impact of Procambarus clarkii, as possible vector of harmful trace element.

Prey partitioning and use of insects by juvenile sockeye salmon and a potential competitor, threespine stickleback, in Afognak Lake, Alaska

AbstractFreshwater growth of juvenile sockeye salmon (Oncorhynchus nerka) depends upon the quality and quantity of prey and interactions with potential competitors in the foraging environment. To a large extent, knowledge about the ecology of lake‐rearing juvenile sockeye salmon has emerged from studies of commercially important runs returning to deep nursery lakes, yet information from shallow nursery lakes (mean depth ≤ 10 m) is limited. We examined seasonal and ontogenetic variation in diets of juvenile sockeye salmon (N = 219, 30–85 mm) and an abundant potential competitor, threespine stickleback (Gasterosteus aculeatus; N = 198, 42–67 mm), to understand their foraging ecology and potential trophic interactions in a shallow Alaska lake. This study revealed that adult insects made up 74% of all sockeye salmon diets by weight and were present in 98% of all stomachs in Afognak Lake during the summer of 2013. Diets varied temporally for all fishes, but small sockeye salmon (&lt;60 mm) showed a distinct shift in consumption from zooplankton in early summer to adult insects in late summer. We found significant differences in diet composition between sockeye salmon and threespine stickleback and the origin of their prey indicated that they also separated their use of habitat on a fine scale; however, the two species showed overlap in size selectivity of zooplankton prey. Considering that aquatic insects can be a primary resource for juvenile sockeye salmon in Afognak Lake, we encourage the development of nursery lake carrying capacity models that include aquatic insects as a prey source for sockeye salmon.

To what extent can specialized species succeed in the deep sea? The biology and trophic ecology of deep-sea spiny eels (Notacanthidae) in the Mediterranean Sea

The population structure, reproductive biology and feeding ecology of the two notacanthids inhabiting the deep Mediterranean, Notacanthus bonapartei and Polyacanthonotus rissoanus, were analyzed in the Balearic Basin at depths from 579 to 2233m (mainly pristine depths or subjected to low fishing impact), including seasonal variations. Preferred average depths (Centres of Gravity, CoG) of Notacanthusbonapartei were situated over the middle slope (942m) and of P. rissoanus on the lower slope (1680m). For both species, bigger individuals collected at the deepest depths had the highest values of a gonadosomatic index (GSI), suggesting that in reproductive periods adults migrate into deeper waters. The reproductive season for N. bonapartei was late summer and autumn; that of P. rissoanus was narrower, restricted to summer. N. bonapartei exploited benthic prey, among identified prey mainly echinoderms (e.g., Penilpidia ludwigi, Hymenodiscus coronata) and sessile benthic organisms (e.g., actinians and polyps of the bamboo coral Isidella elongata). Consumption of bamboo coral polyps by N. bonapartei constitutes a unique specialized trophic strategy and a direct link with such corals. Some differences in the diet composition related to depth were observed, as were a few differences related to periods of water-column stratification and homogenization. Gut fullness (F) of this species was mainly correlated with surface Chlorophyll a recorded 2–3 months before sampling date and somewhat but less so with river discharges 1 month before sampling. That suggests that vertical flux of organic matter was the food source for prey exploited by N. bonapartei. Diet of P. rissoanus was based on epibenthic-suprabenthic crustaceans, e.g. tanaids (Apseudes spp.), isopods (Munnopsurus atlanticus) and amphipods (Rhachotropis caeca) and on polychaetes (Polynoidae, Harmothoe spp.), all these prey more mobile than consumed by N. bonapartei. No significant differences in diet composition were found related with either depth or homogenization/stratification of the water column. This lack of changes in diet is probably attributable to the greater stability of the lower slope where P. rissoanus lives. Gut fullness was mainly correlated with surface Chlorophyll a recorded simultaneously with the fish sampling. Lactate dehydrogenase (LDH) activity was similar in the muscle of the two notacanthids (N. bonapartei=3.72–8.75µmol/min/mg prot; P. rissoanus=7.56µmol/min/mg prot). Values for N. bonapartei were the highest found compared to other deep-sea fish in the deep Mediterranean. This could be related with the special feeding behaviour of this species when it removes sessile prey from substrate.

Ontogenetic and Long‐Term Diet Shifts of a Generalist Juvenile Predatory Fish in an Urban Estuary Undergoing Dramatic Changes in Habitat Availability

AbstractVegetated areas such as seagrass beds provide food and essential habitat for many fish and invertebrate species. In particular, many economically important fishes depend on seagrass beds as nursery grounds. In recent decades, there has been a rapid decline in seagrass coverage due to the development of coastal areas worldwide, altering these ecosystems and their community structure. Within Tampa Bay (Florida's largest estuary), seagrass coverage and water quality underwent a decline followed by a recovery over the past three decades; these changes may have altered the community structure of seagrass‐associated fauna. We examined the diets of juvenile Spotted Seatrout Cynoscion nebulosus, a common estuarine predator, to assess whether documented changes in water quality and habitat were reflected in their trophodynamics. Stomach contents of Spotted Seatrout from Tampa Bay were sampled during three different studies conducted in 1981–1982, 1991–1992, and 2005–2013. We analyzed data from these studies to compare the diet across size‐classes and time periods. Using canonical analysis of principal coordinates, we discerned significant differences in diet composition among size‐classes and among time periods. Ontogenetic shifts in diet during all three time periods were consistent with those previously reported, highlighting the plasticity of a generalist piscivore in a recovering seagrass ecosystem. Subtle shifts in diet were detected among the three time periods, suggesting that changes in seagrass coverage contributed to altered trophodynamics in this estuarine system. Our efforts highlight the utility of using a generalist piscivore's diet as a tool for monitoring and quantifying faunal shifts in an ecosystem.Received July 21, 2015; accepted January 5, 2016 Published online April 18, 2016

FEEDING HABITS AND HELMINTH PARASITES OF SARDINE (S. PILCHARDUS) AND ANCHOVY (E. ENCRASICOLUS) IN THE ADRIATIC SEA

We examined the stomach contents of two of the most economically and ecologically important small pelagic fish species, the sardine, Sardina pilchardus and the anchovy, Engraulis encrasicolus, obtained monthly from commercial purse-seine catches operating on Croatian fishing grounds during a one-year period (January–December, 2011). Both species generally showed a similar diet, with copepod and decapod larvae as dominant prey groups. The composition of anchovy and sardine stomach contents was not size- or sex-related, but throughout the year, a significant difference in diet composition was observed for each species as well as between species. Two gastrointerstinal helminths; the digenean Parahemiurus merus and nematode Hysterothylacium aduncum, were recorded during the stomach content analysis. Differences in population dynamics between the two parasites are congruent with differences in the prey composition of sardine and anchovy, reflecting fine-tuned interactions in the trophic web between parasites and intermediate or paratenic hosts included in the sardine and anchovy diet.

Diet breadth and overlap in three sympatric aerial insectivorous birds at the same location

Capsule We found significant differences in the composition and diversity of diet among House Martins, Barn Swallows and Swifts breeding in the same village in Poland.Aims To evaluate the character and extent of diversity, specialization and overlap of diet between trophically similar nestlings of three species of aerial feeding birds breeding at the same location and differing considerably in foraging height.Methods Diet was determined based on faecal analysis. Differences in composition and diversity of diet and food niche overlap were assessed through multivariate analysis of variance (manova), Shannon Diversity Index and the Pianka index. Diet specialization was measured by application of the Berger–Parker index of dominance.Results manova indicated significant differences in diet composition among all three species. House Martins showed the most diverse diet, Swallows were intermediate and Swifts least diverse. Average body mass of all prey found in the diet of Swifts was nearly three times smaller than in Swallows and two times smaller than in House Martins.Conclusion Our findings show that these three species consume the same types of insect prey, but they take different proportions, and hence biomass, of the major prey groups. House Martins had the widest niche and greatest overlap.