Search

Following the cessation of whaling, the southwest Atlantic humpback whale (Megaptera novaeangliae) population is thought to be close to pre-exploitation size, reversing 20th century changes in abundance. Using a model-based approach applied to concurrently collected data on baleen whale abundance and Antarctic krill (Euphausia superba) biomass in the South Sandwich Islands (SSI) region, we explore ecological interactions between these taxa. Krill biomass and baleen whale density were highest to the north and northeast of the SSI, where the Antarctic Circumpolar Current (ACC) is deflected around the island chain. Humpback whale density was elevated at locations of krill biomass density >150 gm-2. Krill consumption by baleen whales was estimated at 19–29% of the available krill standing stock. We used historic whaling data to confirm the plausibility of these consumption rates and found evidence of rapid weight gain in humpback whales, such that blubber depleted during the breeding season could be restored in a much shorter period than previously assumed. Little is known about krill replenishment rates in the flow of the ACC, or about niche separation between recovering baleen whale populations; both factors may affect species carrying capacities and further monitoring will be required to inform the management of human activities in the region. • Krill biomass density distribution was modelled using a two-stage Maxent/GLM process. • Humpback whale abundance and distribution was modelled using a GAM. • Whales consume 19–29% of available krill in the South Sandwich Islands region. • On southern feeding grounds humpback whales can rapidly restore depleted blubber. • Future studies on rates of krill transport in oceanographic currents will be important. [ABSTRACT FROM AUTHOR]

This study investigated the effect of feeding rates (2-10% of body weight), on the growth performance, feed utilization, and blood-chemistry indicators of nutritional status in juvenile GIFT strain tilapia, (Oreochromis niloticus) initial weight 72.73±0.15g. The 56 day trial conducted in cages tested five groups, with three replicates each. Fish were fed twice a day. Data were analyzed using one way ANOVA. Results showed that final body weight, food conversion rate (FCR), weight gain, specific growth rate (SGR), protein retention efficiency (PRE), protein efficiency ratio (PER), feed intake, and condition factor (CF) were significantly affected by the feeding rates (P<0.05). The broken line method of linear regression analysis, y=17638x-217.9, R2=0.945; y=280x+860.6, R2=1, indicated that maximum weight gain occurred at 6.21% feeding rate. Insulin growth factor-one (IGF-I) level, hepatosomatic index (HSI), white blood cell (Wbc), red blood cell (Rbc), hemoglobin (Hb), and hematocrit (Ht) parameters were not significantly affected by the feeding rates (P>0.05). Serum indicative parameters of liver-enzyme functions and food metabolism, including blood glucose (GLU), triglyceride (TG), total protein (TP) levels, aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) enzyme activities were assayed. Blood glucose level of the fish was significantly affected by the feeding rates (P<0.05). TG and TP levels; AST, ALT and ALP activities were not significantly affected by the feeding rates (P>0.05). Feed provided at a rate of 2%-10% of body weight may meet physiological wellbeing of GIFT strain tilapia, however growth performance and other endocrine functions (IGF-I) are affected by lower and higher feeding rates. Our findings could be very useful to tilapia farmers. [ABSTRACT FROM AUTHOR]

The presence of pharmaceutical drugs in the environment is an important field of toxicology, since such residues can cause deleterious effects on exposed biota. This study assessed the ecotoxicological acute and chronic effects of two anticholinesterasic drugs, neostigmine and pyridostigmine in Daphnia magna. Our study calculated 48 h-EC values for the immobilization assay of 167.7 μg L for neostigmine and 91.3 μg L for pyridostigmine. In terms of feeding behavior, we calculated a 5 h-EC for filtration rates of 7.1 and 0.2 μg L for neostigmine and pyridostigmine, respectively; for the ingestion rates, the calculated EC values were, respectively, 7.5 and 0.2 μg L for neostigmine and pyridostigmine. In the reproduction assay, the most affected parameter was the somatic growth rate (LOECs of 21.0 and 2.9 μg L for neostigmine and pyridostigmine, respectively), followed by the fecundity (LOECs of 41.9 and 11.4 μg L for neostigmine and pyridostigmine, respectively). We also determined a 48 h-IC for cholinesterase activity of 1.7 and 4.5 μg L for neostigmine and pyridostigmine, respectively. These results demonstrated that both compounds are potentially toxic for D. magna at concentrations in the order of the μg L. [ABSTRACT FROM AUTHOR]

Lantana camara is a widespread exotic invasive species in India, capable of dominating and displacing native forage species. We investigated whether L. camara was associated with variation in elephant foraging behavior in Mudumalai Tiger Reserve, India. The behavioral responses of elephants to L. camara were assessed from feeding and stepping rates. Elephants were never observed to feed on L. camara, but rather fed on grass and browse present within and around L. camara patches. A multiple regression analysis showed that feeding rates were negatively associated with L. camara invasion ( F1, 55 = 4.26, R2 = 0.07), but not stepping rates. Instead, grass cover and browse density were associated with stepping rates ( F2, 55 = 11.16, R2 = 0.30). Path analysis indicated that the total effect of L. camara on feeding rates was 11 percent ( β = −0.24) less than the direct negative association ( β = −0.27) owing to a positive indirect association of L. camara with feeding rates through grass cover and browse density ( β = 0.03), while stepping rates were negatively associated with grass cover ( β = −0.39) and positively associated with browse density ( β = 0.38). Our results indicate that L. camara appears capable of modifying feeding rates of elephants, likely through a loss of grass areas due to L. camara invasion. Experimental work is needed to test for causal relationships among the variables we measured, to enhance our understanding of how invasive weeds modify elephant behavior. [ABSTRACT FROM AUTHOR]

Feeding rate is one of the crucial factors to be considered in aquaculture production. In this experiment a 60-day feeding trial was conducted to investigate the influence of different feeding rates on the growth, feed efficiency and survival rates for hatchery produced sea bass Lates calcarifer fed with commercial dry pellets (47.80% protein, 7.10% lipid, 1.62% ash, 0.77% crude fiber and 7.70% moisture). Triplicate groups of sea bass juveniles (weight, 5.50 ± 0.01 g; total length, 6.9 cm) were fed six times a day (09:00 - 10:30 - 12:00 - 13:30 - 15:00 - 16:30) at 3%, 6%, 9% and 12% body weight (BW) offish throughout the feeding trial. Ten fish were stocked in each 12 units conical fiber glass tanks (100L capacity) at three replicates per treatment at the UPV Multi Species Hatchery. The best specific growth rate (SGR) was 0.48±0.11, food conversion ratio (FCR) of 1.97±0.027, feed efficiency (FE) of 0.51±0.013 and protein efficiency ratio (PER) of 1.06± 0.031 were recorded for fish feed at 12% daily application feeding rate and the difference between fish fed at 12% body weight per day was statistically different (p > 0.05) from other groups of sea bass fed at 3, 6 and 9% body weights per day. For the whole body composition, the feed application rate of 12% had a significant effect on the crude protein (18.42±0.00), crude lipid (6.36±0.03) but no significant differences were detected for the ash concentration among the different treatments. The survival rate (80%) of the fish during the experiment did not differ significantly (p < 0.05) among the treatments. At the end of the 60-day feeding trial, the group of fish fed at 12% BW had a significantly higher hepatosomatic index (HSI) of 1.7±0.02 and viscerosomatic index (VSI) of 6.4±1.9 than the rest of experimental groups. The lowest HSI (0.99±0.11) and VSI (3.69±1.1) was achieved by group of fish fed at 3% BW. The condition factor (CF) of 9.65±0.022 was highest in fish fed 12% BW and the lowest (8.05±0.028) was on 3% BW. On the other hand, the groups of fish fed on 9 and 6% BW showed no statistical difference between treatments. Results showed that growth and feed efficiency of hatchery produced L. calcarifer were greatly enhanced by feeding the fish six times daily at 12% as compared to fish fed at 9, 6 and 3% BW using commercial dry pellets. [ABSTRACT FROM AUTHOR]

Hemimysis anomala is a near-shore mysid native to the Ponto-Caspian region that was discovered to have invaded Great Lakes ecosystems in 2006. We investigated feeding rates and prey preferences of adult and juvenile Hemimysis in laboratory experiments to gain insight on the potential for Hemimysis to disrupt food webs. For both age groups (AGs), we measured feeding rates as a function of prey abundance ( Bosmina longirostris as prey), prey type ( B. longirostris, Daphnia pulex, and Mesocyclops sp.), and light levels (no light and dim light). Mean feeding rates on Bosmina increased with prey density and reached 23 ind. (2 h) for adults and 17 ind. (2 h) for juveniles. Dim light had little effect on prey selection or feeding rate compared to complete darkness. When feeding rates on alternate prey were compared, both AGs fed at higher rates on Bosmina than Daphnia, but only juveniles fed at significantly higher rates on Bosmina relative to Mesocyclops. No significant differences were observed between feeding rates on Mesocyclops and on Daphnia. Hemimysis feeding rates were on the order of 30-60% of their body weight per day, similar to predatory cladocerans that have been implicated in zooplankton declines in Lakes Huron and Ontario. [ABSTRACT FROM AUTHOR]

Highlights: [•] Nutrient availability can influence the dynamics of an insect-weed system. [•] We investigated plant compensation and insect feeding patterns in response to variable nutrients. [•] Both plant productivity and insect feeding rates were significantly affected. [•] Environmental nutrient availability will play a role in biocontrol agent efficacy. [•] A knowledge of nutrients and an insect-weed system can direct appropriate weed control strategies. [ABSTRACT FROM AUTHOR]

Walleye ( Sander vitreus) is an important sport fish throughout much of North America, and walleye populations support valuable commercial fisheries in certain lakes as well. Using a corrected algorithm for balancing the energy budget, we reevaluated the performance of the Wisconsin bioenergetics model for walleye in the laboratory. Walleyes were fed rainbow smelt ( Osmerus mordax) in four laboratory tanks each day during a 126-day experiment. Feeding rates ranged from 1.4 to 1.7 % of walleye body weight per day. Based on a statistical comparison of bioenergetics model predictions of monthly consumption with observed monthly consumption, we concluded that the bioenergetics model estimated food consumption by walleye without any significant bias. Similarly, based on a statistical comparison of bioenergetics model predictions of weight at the end of the monthly test period with observed weight, we concluded that the bioenergetics model predicted walleye growth without any detectable bias. In addition, the bioenergetics model predictions of cumulative consumption over the 126-day experiment differed from observed cumulative consumption by less than 10 %. Although additional laboratory and field testing will be needed to fully evaluate model performance, based on our laboratory results, the Wisconsin bioenergetics model for walleye appears to be providing unbiased predictions of food consumption. [ABSTRACT FROM AUTHOR]

During this study (December 2009 to December 2010), underwater visual surveys using the focal animal method were performed in the coastal reefs of Tamandaré, north-eastern Brazil. The aim was to analyse the effects of the life phase (juvenile and adult) and schooling patterns (school and solitary) on the feeding behaviour (foraging rates and substratum preferences) of four species of the genus Haemulon ( Haemulon aurolineatum, Haemulon parra, Haemulon plumieri and Haemulon squamipinna). PERMANOVA analysis ( P < 0·05) indicated that ontogenetic changes and schooling patterns directly influence foraging behaviour. Schooling individuals had low foraging rates (mean ± s.d. = 2·3 ± 2·1 bites 10 min−1) and mobility, usually remaining near the bottom; however, solitary fishes had high foraging rates (mean ± s.d. = 12·5 ± 4·6 bites 10 min−1). Juveniles preferred feeding in the water column (75% of the total number of bites), whereas adults foraged mainly in sand (80%) and bare rock (20%). All four Haemulon species displayed similar patterns of feeding behaviour as well as preferences for foraging sites and display competition for food resources. In contrast, little is known about their habitat use and foraging behaviour over the diel cycle, particularly the newly settled and early juvenile stages. [ABSTRACT FROM AUTHOR]

Abstract: The box jellyfish Carybdea marsupialis has proliferated in some areas of the north-western Mediterranean Sea since July 2008. As for many species, controlled experimentation in the laboratory is needed to improve our knowledge about C. marsupialis, with the ultimate goal of extrapolating the knowledge gained to the marine environment. The aims of this study were to identify the optimal conditions (i.e. aquarium design, environmental parameters and prey type) for the growth and maintenance of this cubomedusa in the laboratory and, additionally, to quantify the feeding rates of the juveniles of this species. We were able to maintain healthy medusae for 140days. During this time they reached the subadult condition (fact corroborated by observing the gonadal tissue), growing from 2 to 15mm in diagonal bell width from June to November 2010, respectively. We observed a progressive shift in their preferred dietary composition as the individuals grew. The medusae fed on Artemia salina nauplii along the entire development. Other, larger, prey types (e.g. Mysis sp., Acartia granii copepods and adult Artemia salina) were progressively ingested at the same time as they increased their umbrella size. We also describe the clearance rates, ingestion rates, prey selectivity and digestion times of juvenile C. marsupialis on natural zooplankton and on the copepod Acartia grani. Growth and mortality rates were also calculated. [Copyright &y& Elsevier]

The invasive ctenophore Mnemiopsis leidyi, which now may be established in the NW Mediterranean, is a voracious predator of zooplankton and ichthyoplankton. Pelagia noctiluca, an abundant scyphomedusa there, eats other gelatinous species. We measured predation, digestion and escape when different sizes of medusae fed on ctenophores. Clearance rates increased with predator size and ingestion rates increased with prey concentration. Digestion times were longer when medusae were smaller than the ctenophores. All large ctenophores escaped from the medusae, but small ctenophores were ingested completely. Pelagia noctiluca is potentially an important predator of M. leidyi that may help control populations of this ctenophore. [ABSTRACT FROM AUTHOR]

This study compared remote underwater video and traditional direct diver observations to assess reef fish feeding impact on benthos across multiple functional groups within different trophic categories ( e.g. herbivores, zoobenthivores and omnivores) and in two distinct reef systems: a subtropical rocky reef and a tropical coral reef. The two techniques were roughly equivalent, both detecting the species with higher feeding impact and recording similar bite rates, suggesting that reef fish feeding behaviour at the study areas are not strongly affected by the diver's presence. [ABSTRACT FROM AUTHOR]

The article focuses on a study done in order to know Chick diet, feeding rates and productivity of the double-crested cormorants (Phalacrocorax auritus) at Tommy Thompson Park, Ontario during 2006 and 2007. It mentions that data for chick diet is collected by using manual abdominal palpation technique, chick feeding rates on weekly basis and Productivity is measured by tree nesting. It found that 86 percent of the diet was composed of Alewife fish and average feed rate 4.5 times in a day.

The article presents a research related to the findings of environmental and within-nest factors influencing feeding patterns of Mediterranean Blue Tits, Cyanistes caeruleus. It is informed that the rate at which parent birds deliver food to their young depends on intrinsic and extrinsic factors such as time and day. It is concluded that the proximate factors influences parental provisioning strategies in altricial birds with biparental care.

Four 1-week growth trials were conducted to determine the effects of feeding rates on the growth performances of white sturgeon ( Acipenser transmontanus) fries 6-9 weeks after initiation of feeding. Six feeding rates with four replications were used in each of the four trials, and the feeding rates were 3.0-8.0, 2.0-7.0, 1.0-6.0 and 1.0-6.0% body weight (BW) per day in 1% increment, respectively. Number of fries per replicate and their initial BW (means ± SEM) were 60, 45, 30 and 30 and 2.8 ± 0.1, 4.5 ± 0.4, 8.5 ± 0.7 and 10.0 ± 0.7 g, respectively. The fries were kept at 18-19 °C and fed a commercial salmonid feed (488 g kg−1 protein and 123 g kg−1 fat). Mortality was low and unrelated to feeding rates. Final body weights, body weight increases, specific growth rates and feed efficiency were significantly ( P < 0.05) affected by the feeding rates. Body moisture and lipid contents were significantly affected by feeding rates except body moisture content in trial II. Body protein contents were not affected by feeding rates except in trial III. Broken-line analysis on specific growth rates indicated that the optimum feeding rates were 6.5 ± 0.4, 4.8 ± 0.2, 4.2 ± 0.1 and 3.8 ± 0.2% body weight per day, respectively, for white sturgeon fries 6-9 weeks after initiation of feeding. [ABSTRACT FROM AUTHOR]

Abstract: The freshwater pulmonate snail, Lymnaea stagnalis, is the most sensitive aquatic organism tested to date for Pb with an estimated EC20 for juvenile snail growth of 3μgl−1. A previous study supported the hypothesis that this hypersensitivity to Pb was due to an extremely high Ca2+ uptake rate needed to support shell formation. The current study sought to build upon this working hypothesis and develop a mechanistic predictive model for inhibition of snail growth as a function of Pb exposure. Initial experiments confirmed previous predictions that juvenile snails have net Ca2+ uptake rates of 7000–8000nmolg−1 h−1, approximately 100-fold higher than observed in a typical freshwater fish. However, an initial time course study revealed that the onset of growth inhibition occurs at least 4d prior to inhibition of net Ca2+ flux in Pb-exposed snails indicating the latter is not the primary mechanism of action. Qualitative observations during this experiment indicated snail feeding was inhibited in a dose-dependent manner. A subsequent experiment demonstrated that when food is withheld from snails for even 24h, net Ca2+ uptake is significantly (∼50%) reduced. A second time course study demonstrated quantitatively that snail feeding is inhibited by Pb exposure by up to 98% at relatively high Pb concentrations (57μgl−1) but no inhibition was observed at ≤10μgl−1 Pb indicating feeding inhibition is not causing observed growth effects at concentrations approximating the EC20 of 3μgl−1 Pb. A final experiment testing whether Pb-induced growth effects are related to inhibition of carbonic anhydrase activity in the snail mantle also failed to demonstrate an effect. We conclude that while both feeding and net Ca2+ uptake in snails are affected by Pb exposure, they appear to be secondary effects. The primary mechanism of action explaining L. stagnalis hypersensitivity to Pb remains to be identified. [Copyright &y& Elsevier]

In species showing delayed natal dispersal, broodmates vary in natal dispersal timing and strategy, where some choose to disperse early while others delay. In the cooperatively breeding red-cockaded woodpecker, Picoides borealis, typically only one juvenile male per brood delays dispersal despite the lifetime fitness benefits associated with delayed dispersal. We sought to determine whether adult favouritism or intrabrood competition over the distribution of natal food resources provides a mechanism for the persistence of individual variation in natal dispersal strategies. We show that fledgling red-cockaded woodpeckers form male-biased, linear dominance hierarchies as a result of frequent aggressive conflicts. For males, high nestling condition relative to male broodmates was a strong predictor of future dominance, and this condition–rank relationship persisted after individuals reached nutritional independence. Adults were never observed interfering with broodmate conflicts, and were only rarely aggressive towards fledglings. Adults showed no overt favouritism towards offspring when targeting individual fledglings during provisioning early in the postfledging period. However, conflict rates increased with decreasing targeted-feeding rates, suggesting that access to resources is an important function of dominance hierarchies. After fledglings were developmentally able to compete for positions near foraging adults, first- and second-ranking males were fed more often than subordinate females. Of the juvenile males surviving to spring, subordinates were more likely to disperse during their first year than were their dominant broodmates. Together, our findings suggest that for young red-cockaded woodpeckers, intrabrood social rank provides a mechanism for prioritized access to natal resources and variation in natal dispersal strategy. [Copyright &y& Elsevier]

The objective of this study was to determine how seasonal changes affect the foraging activity and wood consumption of the Formosan subterranean termite, Coptotermesformosanus Shiraki (Isoptera: Rhinotermitidae), in New Orleans, LA. There was a significant correlation between wood consumption and air temperature, soil temperature, and soil moisture, but not precipitation or number of rainy days. In the first year of the study, wood consumption was the lowest in December, February, and March. Wood consumption in January was not significantly different from consumption during the rest of the year. There were no seasonal changes in the number of underground monitoring stations occupied by termites. In the second year of the study, wood consumption was lowest from January to March. There was a significant decrease in the number of monitoring stations occupied by termites during the winter. This study determined that C. formosanus will remain in monitoring stations and resume feeding during warmer periods of a mild winter if average soil temperatures remain above 15°C. Only prolonged periods of cold weather, with average soil temperatures below 15°C, caused a significant number of termites to abandon underground monitoring stations. Seasonal changes in foraging activity would probably only disrupt baiting programs during severe winters in New Orleans, LA. [ABSTRACT FROM AUTHOR]

Native predators may be important in controlling populations of the invasive ctenophore Mnemiopsis leidyi. We experimentally quantified predation rates of the scyphozoan Cyanea capillata on M. leidyi. Cyanea capillata with 74.8 ± 13.3 mm diameter feeding on 28.7 ± 5.5 mm (total length) M. leidyi in 380 L experimental containers had a maximum clearance rate of 40 ± 11 L ind.−1 h−1 (AV ± SD). Ingestion rate increased linearly through the observed range of prey concentrations (5.3–42.1 m−3). Over 90% of encounters ended in escape, but the escaping M. leidyi suffered damage in the process. [ABSTRACT FROM AUTHOR]

In many coastal environments, variation in salinity and organismal responses to that variation are important determinants of the distribution and abundance of species. This study examined the effects of acute salinity changes on sea stars ( Pisaster ochraceus) collected from a high-salinity site (Bamfield, BC) and a low-salinity site (Vancouver, BC). Sea stars from both sites were exposed to salinities ranging 15–30 psu. Following a 24-h exposure, the osmolality, sodium concentrations, and chloride concentrations in the perivisceral fluid all varied directly with salinity and were very close to the treatment salinities in both the Bamfield and Vancouver sea stars. The righting response (measured as an activity coefficient) was salinity dependent, with the lowest activity levels at a salinity of 15 psu. Activity coefficients did not vary between the two source populations. Feeding rates on mussels were strongly salinity dependent, but the salinity pattern was population specific. Bamfield sea stars fed the most at 30 psu, whereas Vancouver sea stars fed the most at 20 psu. High post-experimental mortalities were observed in Bamfield sea stars that had been exposed to a salinity of 15 psu; no such mortality was observed in Vancouver animals. This study provides evidence that the sea stars from the lower salinity environment had been able to acclimatize or adapt to low-salinity conditions. However, the results also suggest that there are limits to this tolerance, and that future changes in salinity may have important consequences for marine communities via alteration of keystone predation. [ABSTRACT FROM AUTHOR]

The feeding of the cladoceran Daphniopsis studeri on algae and bacteria was investigated under ice in an ultra-oligotrophic Antarctic lake from late autumn (May) to early spring (October) in 2004. D. studeri fed on both algae and bacteria with estimated filtering rates of 0.048 and 0.061 l ind−1 day−1), respectively. Algae seemed to be the major food resource for the D. studeri population, however at times of low algal densities the bacterioplankton represented an important alternative food resource. The D. studeri grazing impact on the algal and bacterial standing stock was in general low (0.6–4.6% removed per day), but during the winter period this organism can remove up to 34% of the bacterial production (BP). At times D. studeri grazing can temporarily have a significant impact on the BP rates, though their impact was relatively low when compared to viral-induced bacterial mortality in the lake. [ABSTRACT FROM AUTHOR]

Abstract: The feeding preferences and consumption rates of the exotic woodlouse Armadillidium vulgare were measured on litters from the autochthonous Rio Grande cottonwood and the exotic Russian olive. When offered a choice between five litter types (green and shed leaves of Russian olive and cottonwood, and fruits of Russian olive), the isopods consumed more of the exotic plant litter (green leaves and the fruits of Russian olive) than of the autochthonous cottonwood. When offered only one diet, consumption rates of green leaves and fruits of Russian olive were again the highest. Feeding was related with N and C:N ratios of the litter, with highest consumption of diets with low and high C:N ratios and lowest consumption of diets with intermediate C:N ratios. The N content was highest (and C:N ratios lowest) on isopods feeding shed leaves of Russian olive. Growth was not related to the amount or the C:N ratio of the food consumed, being highest for animals feeding on shed leaves of cottonwood. Our results show that the consumption patterns and the C and N body composition of the exotic woodlouse A. vulgare are altered when fed with Russian olive litter, suggesting that the replacement of the autochthonous cottonwood by the exotic Russian olive may negatively affect the maintenance of the population of these exotic detritivores in the area. [Copyright &y& Elsevier]

Understanding trophic interactions is essential for the prediction and measurement of structure and function in aquatic environments. Communities in these ecosystems may be shaped by variables such as predator diversity, prey density and emergent multiple predator effects (MPEs), which are likely to influence trophic dynamics. In this study, we examined the effect of key predatory fish in floodplain wetlands, namely Oreochromis mossambicus and Enteromius paludinosus, towards Chironomidae prey, using a comparative functional response (FR) approach. We used single predator species as well as intra- and interspecific paired species to contrast FRs under multiple predator scenarios. Attack rate and handling time estimates from single predator FRs were used to predict multiple predators' feeding rates, which were compared to observe multiple predators' feeding rates to quantify potential MPEs. From single fish trials, each species displayed a significant Type II FR, characterized by high feeding rates at low prey densities. Oreochromis mossambicus had a steeper (initial slope, i.e., higher attack rate) and higher (asymptote of curve, i.e., shorter handling time and higher maximum feeding rate) FR, whereas E. paludinosus exhibited lower-magnitude FRs (i.e., lower attack rate, longer handling time and lower feeding rate). In multiple predator scenarios, feeding rates were well-predicted by those of single predators, both in conspecific and interspecific pairs, and thus we did not find evidence for antagonistic or synergistic MPEs. Predator–prey interactions in wetland systems can have significant consequences on the structure and dynamics of ecological communities. In turn, this could have destabilizing effects on resources in tropical wetlands. These results, although experimental, help us understand how trophic interaction among conspecific or interspecific fish species in Austral tropical wetlands might influence their aquatic prey species. This will help us to understand food web dynamics better. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the change of some biochemical parameters in the aquatic invertebrate Daphnia magna following exposure to the fungicide tebuconazole and to determine the most sensitive biomarker among the ones tested in this species. Four biochemical biomarkers (protein, glycogen, lipids and caloric content) were correlated with feeding behaviour studies of D. magna after fungicide exposure. Juveniles of D. magna were exposed to four sublethal concentrations of tebuconazole (0.41, 0.52, 0.71 and 1.14mgL−1) for 5d. Daphnid samples were taken from each test and control group at 24, 48, 72, 96 and 120h after the start of the experiment. Tebuconazole EC50 values were calculated on D. magna in our laboratory as 56.83 and 40.10mgL−1 at 24 and 48h, respectively. Results showed that daphnid energy content decreased as tebuconazole concentration increased, especially after 96–120h of exposure to 0.52mgL−1 and higher fungicide concentrations. The data suggest that tebuconazole is moderately toxic to D. magna but also that it seriously impairs the metabolic functions, resulting in alterations in biochemical constituents. In the D. magna feeding study, algae feeding rates were inhibited after fungicide exposure. Such findings indicate the importance of feeding studies in laboratory toxicity test as well as their relationship with others studies. The results emphasize the importance of considering different kind of biomarkers to identify and evaluate the biological effect of a fungicide in the aquatic environment. Although the biochemical biomarkers used resultated good indicators of tebuconazole toxicity, feeding rates in D. magna decreased after only 5h exposure to the fungicide resulting in the most sensitive parameter of daphnid fungicide exposure. [Copyright &y& Elsevier]

Abstract: A two-week trial was conducted to study the effect of feeding rates on heat shock protein levels in larval white sturgeon. The larvae (30 day post hatch, 230 mg initial body weight) were fed a commercial feed (12.6% moisture, 49.5% crude protein, 20.7% crude fat, and 8.6% ash) at 5, 15, or 25% body weight per day (BW d−1). Liver heat shock proteins (Hsp) were measured before and after the larvae were subjected to a heat shock from 18 to 26 °C at 1 °C/15 min and maintained at 26 °C for 4 h thereafter. Before heat shock, larvae fed 5% BW d−1 had significantly (P <0.05) lower final body weight, RNA/DNA ratio, whole body lipid and protein content, and Hsp60 and Hsp70 levels but higher protein efficiency ratio, and whole body moisture content than larvae fed the two higher feeding rates. Heat shock significantly induced Hsp60 and Hsp70 levels in the liver of all fish but they were lower in larvae fed the 5% than those fed 15 and 25% BW d−1. Hsp70 level increased much more than Hsp60 after the heat shock suggesting that Hsp70 is a more sensitive biomarker under our experimental conditions. [Copyright &y& Elsevier]

Feeding and survival experiments with three different toxic strains of Alexandrium minutum (AL1V, AL2V, and AMINAR1) revealed that copepods Acartia grani and Euterpina acutifrons were able to consume all A. minutum strains to a similar extent at which they fed on the non-toxic and similar-sized Scrippsiella trochoidea (strain S. T.). Feeding of both copepod species showed a typical satiation response to increasing food concentrations. Ingestion rates of A. grani on the four dinoflagellate strains were always higher than those observed for E. acutifrons. Significant differences ( P < 0.05) were found between these rates for the most toxic strain (AL1V) when comparing both copepod species. For carbon concentrations higher than 800 μg C copepod−1 h−1, ingestion rates of both copepod species on AL1V were higher than those found for S. T., and such behaviour could probably be linked to digestive dysfunction or to the use of part of the accumulated energy in detoxification processes. Survival rates and physiological condition index data suggest that A. grani is more sensitive to A. minutum PSP toxins than E. acutifrons. A long-term exposure experiment (288 h) resulted in 0% survival of A. grani when exposed to AL1V, whereas survival of E. acutifrons was greater than 50% for this strain. For the less toxic AMINAR1 strain, the survival rate of E. acutifrons was 80% compared to 95% survival feeding on S. trochoidea. Our results suggest that both A. grani and E. acutifrons can act, to a different extent, as A. minutum PSP-toxin vectors through the food web. [ABSTRACT FROM AUTHOR]

Abstract: The carnivorous gastropod Concholepas concholepas, known in Chile as “loco”, is a species present only along the Chilean coast line and in central-southern Perú showing high economic and ecological importance. Its fishery, which in the past decades has ranged between 828 (2001) and 24,828 (1980) metric tons per year [SERNAP, 2005. Servicio Nacional de Pesca: Anuarios estadísticos. (http://www.sernap.cl/paginas/publicaciones/anuarios/index_anuario.php)], is based exclusively on the exploitation of wild stocks. So far, there has been limited interest in tackling the biological and technical feasibility of cultivation of C. concholepas. Hence, the knowledge about its early ontogenetic stages (i.e., larval, early postmetamorphic and small juvenile) cultivation is still deficient. In this study we investigated, under laboratory and field conditions, C. concholepas survivorship, growth rates, feeding rates and the onset of sexual reproduction. Competent loco''s larvae were collected in the field and metamorphosed in the laboratory to assess growth rates and survivorship during the first six months of postmetamorphic life. Moreover, using small juvenile C. concholepas of ca. 20 mm of peristomal length, collected in the field, we monitored for the body size and live weight traits in laboratory and field rearing conditions. The feeding of the early postmetamorphics and small juveniles was exclusively based in mono diets of the mussel Semimytilus algosus. The rearing of small juveniles was conducted in two consecutive phases, using two specially designed rearing apparatus. The biochemical content of our laboratory cultivated specimens was compared with values obtained from specimens collected in natural habitats. Their rapid growth and good survivorship makes this species suitable for rearing of cocktail-size specimens (50–60 mm) in less than a year. According to the growing rates reported in this study the legal commercial size of C. concholepas: 100 mm of PL would be reached under field and laboratory conditions in 1.65 and 2.64 years respectively. Moreover, it was found that in our rearing conditions C. concholepas reach sexual maturity in less than a year of benthic life. In summary, considering the findings about C. concholepas high growth rates, and low mortalities, we suggest that our rearing methodologies may be scaled up and implemented for the commercial aquaculture of this unique and valuable muricid. [Copyright &y& Elsevier]

Abstract: The impact of feeding on autotrophic picoplankton (APP) on the ciliate composition of the assemblage was surveyed monthly along a depth gradient in the maar crater, athalassohaline, warm monomictic Lake Alchichica (Puebla, Mexico) from June 2003 to December 2005. Numbers of APP were evaluated from their autofluorescence. DAPI staining and the Fluorescently Labeled Bacteria technique were employed to count ciliates and estimate their feeding rates. A total of 38 taxa of ciliates have been identified using Quantitative Protargol Staining. Peritrichs followed by minute spirotrichs (particularly Halteria grandinella) often numerically dominated the ciliate assemblage and emerged as the most efficient APP feeders. A maximum of 54ciliate cellsml−1 was observed in the surface layer at the end of the mixing period, during the development of diatoms (Cyclotella alchichicana), the cyanobacterial bloom (Nodularia sp.) and its decay. Vorticellids (Pelagovorticella natans, Vorticella sp.) had the highest APP uptake (median 130APPcil−1 h−1). Mixotrophic Euplotes cf. daidaleos were important APP grazers near the oxycline. Scuticociliates (Cyclidium glaucoma, Uronema nigricans and an anaerobic cf. Isocyclidium globossum), were numerically dominant within the hypolimnetic assemblages and did not ingest APP. Generally, APP were not an important food source for the majority of the ciliate assemblage, being positively selected by a few species during the APP decay in aerobic and microaerobic conditions. [Copyright &y& Elsevier]

Abstract: The white-throated Dipper (Cinclus cinclus) is unique among passerine birds by its reliance on diving to achieve energy gain in fast-flowing waters. Consequently, it should have evolved behavioural adaptations allowing responding directly to runoff patterns (one of the assumptions of the Natural Flow Regime Paradigm—NRFP). In this study (October 1998–August 2001), we investigated how behavioural and energy use strategies in Dippers might vary under the natural flow regime of snowmelt-dominated streams in The Pyrénées (France) where natural flow regime is highly seasonal and predictable. We recorded time spent in each of 5 behavioural activities of ringed birds to estimate time–activity budgets and derive time–energy budgets enabling the modelling of daily energy expenditure (DEE). Annual pattern in ‘foraging’ and ‘resting’ matched perfectly the annual pattern of the natural regime flow and there was a subtle relationship between water stage and time spent ‘diving’ the later increasing with rising discharge up to a point where it fell back. Thus, time–activity budgets meet the main prediction of the NRFP. For males and females Dippers, estimates of feeding rates (ratio E obs/E req = observed rate of energy gain/ required foraging rate) and energy stress (M =DEE/Basal Metabolic Rate) also partly matched the NFRP. Maximum value for the ratio E obs/E req was registered in May whilst M peaked in spring. These ratios indicated that Pyrenean Dippers could face high energy stress during winter but paradoxically none during high snowmelt spates when food is expected to be difficult to obtain in the channel and when individual birds were observed spending ca 75% of the day ‘resting’. Annual pattern in DEE did not match the NFRP ; two phases were clearly identified, the first between January to June (with oscillating values 240–280 kJ d−1 ind−1) and the second between July and December (200–220 kJ d−1 ind−1). As total energy expenditure was higher during the most constraining season or life cycle, we suggest that energy management by Dippers in Pyrenean mountain streams may fit the ‘peak total demand’ hypothesis. At this step of the study, it is not possible to tell whether Dippers use an ‘energy-minimisation’ or an ‘energy-maximisation'' strategy. [Copyright &y& Elsevier]

Abstract: While spatial scale is increasingly incorporated into ecological experiments, the effect of temporal scale is explicitly investigated less frequently, despite the potential for temporal-scale dependent results. This study was designed to investigate the effect of variations in stress duration on responses, in a situation where stress duration is driven by natural storm events. Specifically, the utility of combining short-term laboratory and longer-term field transplant experiments in assessing the effect of increased suspended sediment concentrations on suspension-feeding bivalves (Austrovenus stutchburyi and Paphies australis) was tested. Short-term (2 days) feeding responses did not reflect feeding or biomass responses over slightly longer time-scales (8–14 days). Also, stronger biomass responses to suspended sediment concentrations were observed after three months in the field, than after 14 days in the laboratory. For unimodal responses, increased stress duration decreased the peak and shifted its location to lower suspended sediment levels. Using continuous measures of field suspended sediment concentrations, the study was able to determine the temporal scale of variability most related to the response. With such information, field surveys and transplants together make a useful tool, preventing co-occurring factors and changes in the duration and intensity of the factors of interest from obscuring results. [Copyright &y& Elsevier]

Abstract: Seahorses are an important commercial and cultural commodity for medicinal and ornamental use. The effects of food, temperature and light intensity on the feeding behavior of juvenile seahorses, Hippocampus trimaculatus Leach, were investigated. All four age groups of juveniles (5-day, 10-day, 15-day and 30-day groups) tested had only one feeding peak in the afternoon, but the time of the peak differed significantly among groups. The major feeding peak of the 5-day and 30-day groups was at 1430h, the 10-day group at 1630–1830h and the 15-day group at 1630h (P <0.05). For the first 3days, the juveniles preferred copepod (Pseudodiaptomus annandalei) nauplii and Moina (Moina mongolia) nauplii. They altered their feed to copepodites from 4days to 10days and, over 10days, they began to eat copepod adults and Moina. The abilities of juveniles to digest and assimilate their feed were related to developmental stages. It took to digest the feed entirely, 2.5h at 5days postpartum, 3.5h at 10days postpartum and 4h at 15days postpartum. Water temperature affected significantly the feeding rate of juveniles (P <0.01) with an optimum temperature at 26°C. Light intensity also affected the feeding rates of different juvenile groups (P <0.01): 1834lx was the best light intensity to feed juveniles of the 1-day group, 1014lx in the 5-day group and 510lx in the 10-day group. The relationship between the standard length and the wet weight of juveniles was found to be exponential: W =10−2.72211SL2.690562 (R 2 =0.984064, P <0.01). The results obtained in this investigation contribute to the aquaculture potential of H. trimaculatus. [Copyright &y& Elsevier]

Eurasian ruffe are invading habitats in the North American Great Lakes watershed occupied by commercially important native yellow perch. We conducted laboratory experiments to evaluate potential overlap in habitat (macrophytes, mud, cobble) and food (benthic invertebrates) use. Ruffe and yellow perch both preferred macrophytes > cobble > mud in the light, but only ruffe increased their use of mud in the dark. Neither fish density nor food availability affected habitat preferences, and competition for habitat was not evident. For both species, feeding rates were marginally lower in macrophytes but did not differ between species. Our experiments suggest that if ruffe and yellow perch share a habitat (e.g., during invasion or because of predation risk), competition for space will be weak or absent. However, within a shared habitat, competition for food may occur when food is limiting because neither species has a clear advantage in its ability to consume invertebrates in any habitat. [ABSTRACT FROM AUTHOR]

In species with long-term partnerships, optimal mate preferences may differ from actual mate choice, and pair displays that advertise individual quality may be expected. We examined the relationship between nest-building and nestling-provisioning effort in Neotropical Buff-breasted Wrens (Thryothorus leucotis) to determine whether male or female expenditure during nest construction was used as an indicator of subsequent parental ability. Buff-breasted Wrens build two nest types: breeding nests used for raising offspring, and "dormitory" nests built year-round and used by pairs for roosting overnight. The building effort of males was greater than that of their mates for dormitory nests, whereas male and female effort were similar during breeding-nest construction and nestling provisioning. Despite large within-sex variation in building and provisioning efforts, male and female effort within pairs were significantly positively correlated for construction of both nest types and for nestling feeding. Effort expended by males during dormitory-nest construction was positively correlated with nestling-provisioning effort, whereas female building effort was not. No relationship existed between effort in breeding-nest construction and nestling provisioning in either sex. These results suggest that effort in dormitory-nest construction was an indicator of male Buff-breasted Wren parental ability. Females that survived to the year following observation built dormitory nests at a lower rate than those that disappeared, which suggests that nest budding may be costly and that by building more than females, males may increase the survival prospects of their partners. Dormitory-nest building by males may play dual roles throughout the year, indicating parental ability and investment in the partnership. [ABSTRACT FROM AUTHOR]

Despite the potential importance of predation as a process structuring coral reef fish communities, few studies have examined how the diet of piscivorous fish responds to fluctuations in the abundance of their prey. This study focused on two species of rock-cod, Cephalopholis cyanostigma (Valenciennes, 1828) and Cephalopholis boenak (Bloch, 1790) (Serranidae), and monitored their diet in two different habitats (patch and contiguous reef) at Lizard Island on the northern Great Barrier Reef, Australia, over a 2-year period. The abundance of the rock-cods and the abundance and family composition of their prey were monitored at the same time. Dietary information was largely collected from regurgitated samples, which represented approximately 60% of the prey consumed and were unbiased in composition. A laboratory experiment showed that fish were digested approximately four times faster than crustaceans, leading to gross overestimation of the importance of crustaceans in the diet. When this was taken into account fish were found to make up over 90% of the diet of both species. Prey fish of the family Apogonidae, followed by Pomacentridae and Clupeidae, dominated the diet of both species of rock-cod. The interacting effect of fluctuations in prey abundance and patterns of prey selection caused dietary composition to vary both temporally and spatially. Mid-water schooling prey belonging to the families Clupeidae and to a lesser extent Caesionidae were selected for over other families. In the absence of these types of prey, apogonids were selected for over the more reef-associated pomacentrids. A laboratory experiment supported the hypothesis that such patterns were mainly due to prey behaviour. Feeding rates of both species of rock-cod were much higher in summer than in winter, and in summer they concentrated on small recruit sized fish. However, there was little variation in feeding rates between habitats, despite apparent differences in prey abundance. In summary, our observations of how the feeding ecology of predatory fish responded to variation in prey abundance provide potential mechanisms for how predation may affect the community structure of coral reef fishes. [Copyright &y& Elsevier]

Abstract Individual growth rates, feeding rates (%BWd[sup -1]) and food conversions for cuttlefish (S. officinalis) hatchlings and juveniles were determined during this study. A flow-through system was used. Water temperature reached 30 °C during the hottest part of the day, gradually decreasing to 25 °C during the night; salinity varied between 37 ± 3 ppt and lights were kept on for 14 h day[sup -1]. Hatchlings were placed in separate compartments with a water volume of 1.2 L. Juvenile cuttlefish (from 0.5 to 25 g) were placed in bigger baskets, with a water volume of 5.2 L. Water flow was 120 L h[sup -1]. The biggest cuttlefish used in these experiments (> 25 g) were gathered in groups of five and placed in circular tanks (water volume of 250–300 L). Thus, results obtained in this case are means and not individual data. During the first 10, 20, 30 and 40 days, mean growth rates (of all individuals sampled by age group) decreased consistently (11.8 ± 4.1, 9.8 ± 1.8, 8.1 ± 2.2 and 7.3 ± 0.7%BW[sup -1] respectively); in similar fashion, mean feeding rates decreased with age group (33.7 ± 13.5, 22.0 ± 7.9, 17.3 ± 3.9 and 16.7%BWd[sup -1] respectively). Mean food conversions varied between 3.6 and 2.5 between the age groups. When grouping results by weight class, similar patterns occur, as growth and feeding rates decrease consistently as cuttlefish grow bigger. Highest mean growth and feeding rates are obtained by hatchlings (< 0.1 g) with 12.4 ± 4.5 and 35.3 ± 15.1%BWd[sup -1], respectively, while the lowest growth and feeding rates were recorded for the largest animals, between 15 and 25 g (3.4 ± 1.1 and 10.8 ± 4.1%BWd[sup -1] respectively). For these weight classes, mean food conversions varied between 2.7 ± 0.9 and 3.8 ± 2.8. [ABSTRACT FROM AUTHOR]

The fitness consequences of male parental care are central to life-history models of reproductive effort and the evolution of social and genetic mating system However in a 4-year study (1992–1995) of Savannah sparrows (Parsserculs sandwichensis) nesting on Kent Island, New Brunswick, Canada, male parental care during the nestling stage was only weakly related to offspring quality and survivorship. Females compensated for poor paternal performance by elevating their feeding rates, and they thus ameliorated selection on male parental care. The likelihood and size of subsequent broods was also unrelated to male feeding effort, suggesting the absence of some indirect (or ‘female-mediated’) benefits. These results were confirmed by an experiment in which male removal resulted in increased female feeding rates but had little effect on the number or quality of young. In contrast, previous research with multilocus DNA fingerpnnting revealed a strong, positive relationship between a male's parental effort and his subsequent fertilization success. Together, this research suggests that the proximate and ultimate targets of male feeding effort can be disiinct traditional assumptions regarding the function of male parental care in birds may therefore be incomplete. [ABSTRACT FROM AUTHOR]

The population dynamics and the trophic role of Aurelia aurita medusae in the Kiel Bight/western Baltic are described from nine years of investigation between 1978 and 1993. There is considerable yearly variation in standing stock with summer median abundance ranging from 0.2 to 16 ind. 100 m−3 and biomass from 0.2 to 4.4 g C 100 m−3. The lower variation is due to marked differences in size of adult medusae between years. In years of low abundance medusae exhibit an average dise diameter of about 30 cm and weight about 1 kg. In bloom years, however, adult size is only about 20 cm and weight ranges between 200 and 400 g. Estimates of feeding are somewhat contradictory, but feeding rates of 40–80 mg C ind.−1 day−1 seem probable. It can be concluded that Aurelia medusae consume about 2/3 of daily secondary production in years of high abundance, and are thus responsible for a decline of mesozooplankton in these years. [ABSTRACT FROM PUBLISHER]

Stomach content analysis of 20 pregnant ( x body mass=13.4 g) and 18 lactating ( x body mass=11.5 g) female Tadarida brasiliensis revealed that the diet, expressed as percent volume, consists largely of lepidopterans, coleopterans, hymenopterans, and dipterans, in decreasing order of importance. We found no significant difference in the diet of pregnant and lactating females when expressed as percent volume. However, when expressed as percent frequency, proportionately more pregnant females fed on lepidopterans, coleopterans, and dipterans than did lactating bats, and proportionately more lactating females fed on hymenopterans. We found no significant differences in the percentages of water, lean dry mass, fat, and energy density in the stomach contents of pregnant and lactating females. Water in stomach contents averaged 62.7% and fat and lean dry mass averaged 22.2% and 15.2%, respectively (expressed as percentage of wet mass); energy density averaged 31.2 kJ g dry mass. This relatively high energy density of stomach contents, as compared to whole insects, can be attributed to the consumption of insects high in fat (especially flying ants) and the abdomens only of moths and beetles (other body parts being discarded). Estimates of nightly food intake increased markedly from mid- to late pregnancy, stabilized or decreased during late pregnancy, and increased again during early to mid-lactation. Average nightly feeding rate doubled from pregnancy to lactation and increased threefold during the first half of lactation. By adjusting our gravimetric estimates of nightly feeding rate upwards by 40% (based on estimates of field metabolic rate), we estimate that the average nightly energy intake of female T. brasiliensis ranges from 57 kJ day in early lactation to 104 kJ day in mid-lactation. These estimates represent nightly feeding rates averaging 39% and 73% of a female's body mass in the period from early to mid-lactation, respectively. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the effects of the feeding rate (0%, 2.5%, 5.0%, 7.5%, and 10% of body weight per day; BW.d−1) on growth performance, nutritional efficiency, and profitability of Nile tilapia (Oreochromis niloticus) juveniles (3.1 ± 0.1 g) using the biofloc technology (BFT) system for 70 days. Fish were randomly stocked (15 fish. Tank−1) in 24 experimental units (50 L), while water quality parameters remained within acceptable limits for the species during the experiment. Animal performance parameters were influenced by feeding rates (P < 0.05), but not survival (P > 0.05), which remained around 81%. Final body weight, weight gain, and thermal growth coefficient increased significantly (P < 0.05); however, the gradual increase in feeding rates had reduced feed efficiency, protein, and energy productive values (P < 0.05). Whole-body lipid and gross energy increased significantly (P < 0.05) as the feeding rate increased, while the moisture content showed an opposite trend up to 5.0% BW.d−1. The results show that Nile tilapia juveniles raised in the BFT system should be fed between 4.3 and 6.1% BW.d−1 to exhibit improved profitability and growth. • Optimum feeding rate in nursery phase (3–30 g) of Nile tilapia reared in a BFT system is 6.1% BW.day−1. • From an economic viewpoint 4.3% BW.day−1 is recommended for tilapia juveniles in a BFT system. • Nile tilapia juveniles can be strategically maintained for 70 days while feeding only on bioflocs. • After 70 days of feeding only on bioflocs tilapia growth was equivalent around 20% than that of fish fed 6.1% BW.day−1. [ABSTRACT FROM AUTHOR]

The environmental effects of nanoplastics-NPLs have been addressed mainly through short-term exposures to a few types of polymers, neglecting other NPLs that are economically relevant like polymethylmethacrylate - PMMA. This work aimed to assess long-term effects of PMMA-NPLs on the marine primary consumer Brachionus plicatilis , evaluating the influence of different exposure routes (waterborne, foodborne and both) and food items (Nannochloropsis gaditana and Tetraselmis chuii). Rotifers were 21 days exposed to: a) control, with clean medium and food- CTR ; b) contaminated medium (8.1 mg PMMA-NPLs/L) and clean algae- MC ; c) clean medium and contaminated algae (pre-incubated for 96 h on 8.1 mg PMMA-NPLs/L)- AC ; and, d) contaminated medium and algae– MC/AC. Mortality (l x), total number of organisms (TN), fecundity (m x), populational growth rate (r), generational time (gt), and feeding rates were assessed. Effects on r and m x were found after 21 days. Organisms from AC had higher r than MC. MC/AC organisms performed better than control in all endpoints. Overall organisms fed with N. gaditana had higher TN, m x and r than those fed with T. chuii. In the AC treatments, rotifers fed with N. gaditana had higher m x. Results highlight that exposure route and food type may modulate NPLs' effects, supporting the need for standardization of assays. [Display omitted] • Long-term effects of PMMA-NPLs in water, food and their combination were assessed. • PMMA-NPLs long-term exposure through food increased rotifers reproduction output. • T. chuii promoted better reproductive output in exposed organisms than N. gaditana. [ABSTRACT FROM AUTHOR]

The new feeding rates for furbearers allow reducing the level of protein in their rations. A structure of feeds is proposed which includes new unconventional feeds and waste products of various industrial processes. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the existence of offspring recognition in the Lesser Kestrel Falco naumanne. It also analyzes the difference between males and females in offspring recognition. The study was focused on the late nesting phase when nestling were between 223 and 30 days old. The researchers observed no females and only a few males were able to recognize their offspring consistently. They also observed that offspring recognition is much poorer in the Lesser Kestrel compared to colonial marine birds, which they assert can be explained by differences in feeding rates and the type of prey delivered to nestlings.

• Increase carbon dioxide decreases cilia beat frequency for blue mussel. • Ocean acidification decreased clearance rates in blue mussels. • Ocean acidification resulted in changes in particle selection for marine bivalves. Gills of marine bivalves, the organs that mediate water flow for feeding and other physiological functions, are exposed to increasing levels of carbon dioxide (CO 2) in seawater, in response to ocean acidification (OA). We examined the effects of elevated dissolved CO 2 upon filtration and feeding behavior of the blue mussel, Mytilus edulis, under field conditions and in laboratory studies. We further investigated possible changes in cilia beat function in response to elevated dissolved CO 2. Physiological filtration and feeding variables measured; included clearance, filtration, organic ingestion, and assimilation rates and selection efficiency, which decreased with increasing CO 2. Absorption efficiency was not affected by dissolved CO 2. Cilia beat frequency declined in excised lateral cilia (lc) exposed to increasing CO 2 levels, which appears to account for decreased clearance rates observed in field and laboratory experiments. Our data suggest that under conditions of increased CO 2 blue mussels will experience changes in physiological filtration, feeding rates, and cilia beat function that could have consequences for fitness and performance. [ABSTRACT FROM AUTHOR]