Food of roach (Rutilus rutilus) and ide (Leusiscus idus): significance of diet shift for interspecific competition in omnivorous fishes.

A rapid increase in global population and wealth has led to a growing demand for animal-based foods, posing significant environmental and health challenges. This study examines the relationship between GDP per capita and the supply of animal-based foods and proteins, using country-level panel data and a polynomial model to explore the Environmental Kuznets Curve hypothesis. We find a non-linear, N-shaped relationship: animal food supply and animal proteins rise with GDP, decline at intermediate income levels, and increase again at higher incomes. Maxima occur at $35,000 for shares and $40,000–$50,000 for absolute supplies. Estimated income elasticities are inelastic, though their sign varies across the income distribution. Moreover, regional differences are notable: Europe exhibits clear N-shaped curves, Asia and Latin America show predominantly monotonic increases with only weak curvature and Africa displays near-linear growth. Projections under SSP – RCP scenarios suggest continued increases in animal food and protein supply through 2050. Our findings indicate that economic growth alone is unlikely to curb rising animal consumption and its associated negative health and environmental impacts. Effective policy interventions and dietary shifts will be required to align future diets with sustainability and public health goals.

Karosienė J., Kasperovičienė J., 2012: Peculiarities of epiphyton algal communities formation on different macrophyte species [Skirtingų makrofitų rūšių epifitono dumblių bendrijų formavimosi ypatumai]. - Bot. Lith., 18(2): 154-163. The epiphyton on different aquatic vegetation represented by emerged macrophytes (Phragmites australis, Equisetum fluviatile, Schoenoplectus lacustris), floating-leaved plants (Nuphar luteum) and submerged macrophytes (Potamogeton perfoliatus, Chara rudis) was studied in two meso- and mesoeutrophic lakes. The morphological characteristics, physiological and synecological peculiarities of plant host had more effect on epiphyton algae abundance and biomass than species richness. The highest densities of algae were associated with helophytes Phragmites australis, Equisetum fluviatile, the lowest was recorded on Schoenoplectus lacustris and laminae of Nuphar luteum. Loosely attached diatoms prevailed on helophytes, adnate species on Nuphar luteum laminae. Cyanobacteria and green algae were more abundant on Nuphar luteum laminae and Potamogeton perfoliatus.

<p class="MsoListParagraph" style="margin: 0cm 0cm 6pt 14.2pt; text-align: justify; text-indent: 21.25pt; line-height: normal;"><span style="font-size: 10pt;" lang="en-us" xml:lang="en-us">The objectives of this research were to: (1) analyze animal food supply in West Lampung District; (2) analyze ideal animal food target and; (3) analyze animal food self sufficiency. This research was conducted by using retrospective and prospective design. The primary data was collected by conducting interview and giving questionnaire to the chosen sample. The secondary data was processed by using Food Balance Sheet (FBS) software to measure animal food supply including the number and the energy and protein content. Food self sufficiency was analyzed by production-supply and import-supply ratio. The average animal food supply in 2005, 2006, and 2007 is 21 g/capita/day or 7.66 kg/capita/year, still lower than ideal supply 60 g/capita/day or 21.90 kg/capita/year. Protein supply of animal food is 2.86 g/capita/day, lower than ideal supply 4.8 g/capita/day.</span></p>

Abstract–Habitat is important in determining stream carrying capacity and population density in young Atlantic salmon and brown trout. We review stream habitat selection studies and relate results to variable and interacting abiotic and biotic factors. The importance of spatial and temporal scales are often overlooked. Different physical variables may influence fish position choice at different spatial scales. Temporally variable water flows and temperatures are pervasive environmental factors in streams that affect behavior and habitat selection. The more frequently measured abiotic variables are water depth, water velocity (or stream gradient), substrate particle size, and cover. Summer daytime, feeding habitats of Atlantic salmon are size structured. Larger parr (>7 cm) have a wider spatial niche than small parr. Selected snout water velocities are consistently low (3–25 cm. s−1). Mean (or surface) water velocities are in the preferred range of 30–50 cm. s−1, and usually in combination with coarse substratum (16–256 mm). However, salmon parr demonstrate flexibility with respect to preferred water velocity, depending on fish size, intra‐ and interspecific competition, and predation risk. Water depth is less important, except in small streams. In large rivers and lakes a variety of water depths are used by salmon parr. Summer daytime, feeding habitat of brown trout is also characterized by a narrow selection of low snout water velocities. Habitat use is size‐structured, which appears to be mainly a result of intraspecific competition. The small trout parr (<7 cm) are abundant in the shallow swift stream areas (<20–30 cm depths, 10–50 cm. s−1water velocities) with cobble substrates. The larger trout have increasingly strong preferences for deep‐slow stream areas, in particular pools. Water depth is considered the most important habitat variable for brown trout. Spatial niche overlap is considerable where the two species are sympatric, although young Atlantic salmon tend to be distributed more in the faster flowing and shallow habitats compared with trout. Habitat use by salmon is restricted through interspecific competition with the more aggressive brown trout (interactive segregation). However, subtle innate differences in behavior at an early stage also indicate selective segregation. Seasonal changes in habitat use related to water temperatures occur in both species. In winter, they have a stronger preference for cover and shelter, and may seek shelter in the streambed and/or deeper water. At low temperatures (higher latitudes), there are also marked shifts in habitat use during day and night as the fish become nocturnal. Passive sheltering in the substrate or aggregating in deep‐slow stream areas is the typical daytime behavior. While active at night, the fish move to more exposed holding positions primarily on but also above the substrate. Diurnal changes in habitat use take place also in summer; brown trout may utilize a wider spatial niche at night with more fish occupying the shallow‐slow stream areas. Brown trout and young Atlantic salmon also exhibit a flexible response to variability in streamflows, wherein habitat selection may change considerably. Important topics in need of further research include: influence of spatial measurement scale, effects of temporal and spatial variability in habitat conditions on habitat selection, effects of interactive competition and trophic interactions (predation risk) on habitat selection, influence of extreme natural events on habitat selection use or suitability (floods, ice formation and jams, droughts), and individual variation in habitat use or behavior.

Communities include habitat generalists whose resource use overlaps specialists. Habitat selection is a mechanism that allows competing species to coexist. Interspecific competition can facilitate coexistence directly or through promoting differential habitat selection. Habitat selection and interspecific competition can vary with population density; however, their roles in determining relative abundance of species across habitat space are poorly understood. We studied Peromyscus keeni, which flourishes in a range of habitats in southeastern Alaska, and Myodes gapperi, a specialist of mature coniferous forests in western North America, to elucidate how these mechanisms may facilitate coexistence in temperate rainforest. We used stepwise multiple regressions of minimum known alive (standardized to unit variance) across 1 ha grids during spring 1999–2000 and autumn 1998–2000 to determine contributions each variable, in each significant regression model, made to the variance in abundance for each species. We determined relative contributions of interspecific competition versus habitat selection in explaining species' habitat use among four different types of rainforest habitat. Intensity of interspecific competition (both directions) varied with population density and season. Habitat variables, rather than interspecific competition, explained variation in species' abundance at population peaks when intraspecific competition would be intense. Interspecific competition, with habitat, was significant at all other times. Our findings suggest habitat selection and interspecific competition explain variation in the abundance of both species among habitats, but contributions vary seasonally and with density. During spring, interspecific competition seemingly plays a greater role at higher densities, but during autumn interspecific competition increases its relative contribution as population density decreases.

This review clarifies important points on habitat selection by the Swamp Rat Rattus lutreolus (Rodentia: Muridae), a species that has been the subject of much research in Australia and has provided a useful model for understanding ecological and biological processes. It also provides an opportunity to cite important earlier research, not readily available through electronic search engines, thus bringing it into current literature to avoid its disappearance into Internet obscurity. We comment on some papers in the literature to correct errors detected and to emphasize the importance of due care in all aspects of a research project, including its reporting. We show that both floristic and structural components have been reported as important to an understanding of habitat and microhabitat selection by R. lutreolus and conclude that it is vegetation density that is of paramount importance. Female R. lutreolus are clearly dominant in driving microhabitat selection, occupying the ‘best’ or densest habitats with male R. lutreolus occupying the next best and Pseudomys or other species, where present occupying the remainder. This demonstrates the important role that intraspecific and interspecific competition play in determining habitat selection. Direct predation and the perception of predation risk may also play a role in habitat selection, again perceived to be pushing individuals towards denser vegetation, representing ‘better cover’. Whether these effects operate as bottom‐up or top‐down needs careful consideration. Climatic variables, such as ENSO‐affecting productivity, and related variables such as temperature and humidity may also play important roles in habitat selection, as can disturbance effects such as wildfire. The relative importance of all of these potential determining factors may vary from place to place, particularly when climatic clines are involved.

Shallow lakes are often rich in submerged macrophytes that play an important role in functioning of shallow lake ecosystems. Omnivorous fish can intensify eutrophication by enhancing the growth of phytoplankton, leading to higher water turbidity and light attenuation with negative effect on the growth of submerged macrophytes. However, the effects of different omnivorous fish species on aquatic ecosystem are not necessarily the same. A 70-day outdoor experiment was conducted in mesocosms containing meadow-forming arrowhead (Sagittaria sagittifolia) and canopy-forming clasping leaf pondweed (Potamogeton perfoliatus) to test the hypothesis that different species of omnivorous fish, the native species Rudd (Scardinius erythrophthalmus) and invasive Prussian carp (Carassius auratus gibelio) have different effects on plankton and benthic algae communities, water quality and submerged macrophytes growth. Both fish species increased the phytoplankton biomass and the concentrations of total and inorganic suspended solids and decreased water transparency and Prussian carp had a stronger effect than Rudd. The fish also changed the phytoplankton composition decreased the densities of zooplankton, except rotifers with more pronounced impact by the Prussian carp. Rudd decreased the dry weight of the above-ground part of arrowhead and of pondweed roots, while Prussian carp decreased the biomass of the whole pondweed. Canonical analyses showed that impact of all studied factors on pondweed growth was 2.6 times greater in Prussian carp than in Rudd treatments. Our findings thus showed differential effects of the two omnivorous fish species on plankton communities, water quality and submerged macrophytes, with Prussian carp having more pronounced impact than Rudd.

China's food security has a great influence on the world, and has always been the top priority in China. In recent years, as the concept of food security is evolving into one of nutrition security and the importance of food diversity is increasing, research based on nutrition security and broad food systems are increasingly needed in today's China. Thus, not only for human consumption, but also animal foods have been integrated into the Food Equivalent, which is used to analyze China's current agriculture system and reveal the water resource distribu- tion. The results indicated that the average animal food consumption has risen by 78.6%, and now China's daily supply of animal food per capita has reached about 50% of that in the USA and 80% of that in the South Korea. So there exist an obvious disparity in animal food supply between China and these two countries. It is impossible for the China's current agricultural system to achieve the level in the USA. Under China's current agricultural system, the consumption proportion of feed had surpassed the consumption of food grain, increased sharply from 33% in 1992 to 67% in 2011. However, the growth potential of total output is approaching an upper limit, so the continued growth of feed demand exerts great pressure on the China's food supply. The discordance of the spatial distribution of water resource and virtual water revealed that China's current agriculture system had a low efficiency in being able to achieve food and nutrition security. China's current grain farming cannot meet the demand of increasing nutrition and appropriate resource utilization. The implementation of grassland agriculture appears feasible and necessary for saving feed grain, providing a large number of high-quality animal foods and appropriate water resource utilization.

ASYMMETRIC COMPETITION, HABITAT SELECTION, AND NICHE OVERLAP IN JUVENILE SALMONIDS

Habitat selection by the muskrat (Ondatra zibethica), as reflected by house location, was studied over a 7-yr period (1970-1976) in a shallow lake, rich in emergent aquatic plants (belts of sedges, water horsetail (Equisetumfluviatile), and bulrush (Schoenoplectus lacustris)), in northern Sweden. The houses were built in or very close to the water, and were constructed with the plant material available near the house site. Most houses were found in about 0.3 m of water and they were often situated on locally elevated points. The spatial distribution of inhabited houses during the peak year was random in late June, but contagious in late October. The shallow sedge belt was most utilized in May and June, but was to a large extent abandoned later on, when the deeper water horsetail belt became well stocked. In late October the outer bulrush belt was also exploited, although only to a minor extent, as during other parts of the year. Utilization of bulrush was determined by the seasonally-prevailing water depth rather than population size. The water horsetail belt was utilized increasingly in late October with the increase in the muskrat population, but only up to a certain level, after which the sedge belt was utilized instead. J. WILDL. MANAGE. 42(3):540--49 The muskrat, previously confined to North America, was introduced into Europe in 1905. Its present range in Europe and Asia covers an area greater than the former, natural distribution area in USA and Canada (Hoffmann, in litt.). Around 1950 the species entered northern Sweden and soon occupied vast areas (Marcstrom 1964, Danell 1977a), where, as in Finland (Artimo 1960), it is most abundant in well-vegetated localities, usually building its houses in lakes and digging burrows in riverbanks (Danell 1978b). For studies concerning the impact of muskrats on plant (Danell 1977b) and animal life in Swedish lakes a detailed knowledge of the factors influencing its habitat selection was needed. Because muskrats build their houses throughout the ice-free season, then abandon some of them and later perhaps reoccupy them, it was assumed that the distribution of inhabited houses at any given moment reflected the habitat selection habits of the population as a whole. The individual houses are short-lived, as they are destroyed by the spring flood, while burrows can persist in use for many years. H wever, it is more difficult to check whether burrows are inhabited or not, so it was therefore desirable to choose a lake at which only houses were present. This requirement is fulfilled in lakes with very shallow shores, where muskrats only construct houses (Danell 1978b). The aim of this investigation was to study habitat selection by the muskrat in a lake, paying special attention to any seaso al differences shown during the ice-free season, as well as to any differences due to population size, i.e., between years with low and high muskrat densities. The study was carried out during a 7yr period (1970-76) in a shallow lake in northern Sweden, where the muskrat population had not been disturbed by trapping. This study was sponsored by the Research Committee of the Swedish National Environment Protection Board (contract 6-3/73-76). I am further indebted to L.-O. Eriksson, A. Gothberg, V. Marcstrom, K. Sjoberg, and T. Sorlin for 540 J. Wildl. Manage. 42(3):1978 This content downloaded from 157.55.39.223 on Wed, 24 Aug 2016 04:43:10 UTC All use subject to http://about.jstor.org/terms MUSKRAT HABITAT SELECTION Danell 541 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..... ..... .. .. . . . .. .. .. . . . .. .. . . .... .... ... ... ... ... . . . . . . . . . . . . . . I) i~:: ~ Ii:?I; Y;~~q~q b9 t :czsjup:HER F-' ~ ~ b~~5HHE 40 H+E FE FE......... iX 65 W. I~ . ... . .... .... ... ... .... .... .... ... ... . . . . .

Plant composition and species relations on the Huntingdon Marsh, Quebec

Transplantation of submerged macrophytes has been widely used to improve water quality in restoring shallow lakes in China. However, in some lakes, small omnivorous fish predominated the fish assemblages and fed mainly on submerged macrophytes. Despite significant research examining grazing selectivity in herbivorous fishes, macrophyte feeding preferences of small omnivorous fishes are poorly understood. We conducted a mesocosm experiment to examine the effects of a prolific small omnivorous bitterling fish Acheilognathus macropterus on the relative growth rate (RGR) and biomass of submerged macrophytes (Ceratophyllum demersum, Myriophyllum spicatum, Vallisneria denseserrulata, and Hydrilla verticillata). Our results showed that the presence of A. macropterus significantly increased nutrient concentrations (e.g. total nitrogen and total phosphorus). The RGR of C. demersum in the bitterling-present treatment was significantly lower than the controls, in the presence of other macrophyte species. Further, total biomass of the four species of macrophytes in the fish-present mesocosms was markedly lower than in the fish-absent treatment, suggesting considerable consumption of macrophytes by bitterling. Moreover, the percent biomass of V. denserrulata and H. verticillata were significantly enhanced by the presence of bitterling. Our findings suggest that A. macropterus may increase nutrient concentrations through excretion and reduce the biomass and RGR of certain submerged macrophytes which may shift macrophyte community structure via selective grazing.

Studies suggest that, unlike the situation in temperate lakes, high biomasses of omnivorous fish are maintained in subtropical and tropical lakes when they shift from a turbid phytoplankton-dominated state to a clear water macrophyte-dominated state, and the predation pressure on large-bodied zooplankton therefore remains high. Whether this reflects a higher degree of herbivory in warm lakes than in temperate lakes is debatable. We combined food web studies using stable isotopes with gut content analyses of the most dominant fish species to elucidate similarities and differences in food web structure between a clear water macrophyte-dominated basin (MDB) and a turbid phytoplankton-dominated basin (PDB) of Huizhou West Lake, a shallow tropical Chinese lake. The δ13C–δ15N biplot of fish and invertebrates revealed community-wide differences in isotope-based metrics of the food webs between MDB and PDB. The range of consumer δ15N (NR) was lower in MDB than in PDB, indicating shorter food web length in MDB. The mean nearest neighbor distance (MNND) and standard deviation around MNND (SDNND) were higher in MDB than in PDB, showing a markedly low fish trophic overlap and a more uneven packing of species in niches in MDB than in PDB. The range of fish δ13C (CR) of consumers was more extensive in MDB than in PDB, indicating a wider feeding range for fish in MDB. Mixing model results showed that macrophytes and associated periphyton constituted a large fraction of basal production sources for the fish in MDB, while particulate organic matter (POM) contributed a large fraction in PDB. In MDB, the diet of the dominant fish species, crucian carp (Carassius carassius), consisted mainly of vegetal matter (macrophytes and periphyton) and zooplankton, while detritus was the most important food item in PDB. Our results suggest that carbon from macrophytes with associated periphyton may constitute an important food resource for omnivorous fish, and this may strongly affect the feeding niche and the strength of the top-down trophic cascade between fish and zooplankton in the restored, macrophyte-dominated basin of the lake. This dual effect (consumption of macrophytes and zooplankton) may reduce the chances of maintaining the clear water state at the prevailing nutrient levels in the lake, and regular removal of large crucian carp may therefore be needed to maintain a healthy ecosystem state.

Fat uptake during deep-fat frying of coated and uncoated foods

Purpose – The purpose of this paper is to assess the sustainable food procurement (SFP) of members of the British and Irish Association of Zoos and Aquariums (BIAZA). It also considered the inconsistencies between their animal and human food supply chains, as well as between their procurement priorities and practices. Design/methodology/approach – A quantitative, cross-sectional approach was employed, involving the use of a web-based questionnaire to gather data from 41 BIAZA members across 21 indicators of food sustainability. The results were considered within a sustainable supply chain management (SSCM) framework. Findings – There was considerable variation amongst the issues considered by zoos during the SFP process for their animal and human food operations. For both, local expenditure, nutritional content and packaging reduction were some of the highest scoring indicators in practice and as priorities. The overall levels of SFP were found to be equal between the human and animal food supply chains. Significantly low levels of inconsistency were found between the two, practically and in terms of procurement aspirations. Within both supply chains, there was also very few significant gaps between procurement priorities and actions. Originality/value – The originality of this study lies in its comparison of procurement practices and priorities for two contemporaneous but distinct food supply chains. It demonstrates that it is possible to have a high overall degree of consistency between two parallel, but contrasting, supply chains, as well as between procurement priorities and priorities. It will be of use in SSCM, particularly within values-led organisations.