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At least 19 recordsLinked to original sources
PubMed2006

Gizzard shad put a freeze on winter mortality of age-0 yellow perch but not white perch.

Four decades of observations on the limnology and fishes of Oneida Lake, New York, USA, provided an opportunity to investigate causes of mortality during winter, a period of resource scarcity for most juvenile fishes, in age-0 yellow perch (Perca flavescens) and age-0 white perch (Morone americana). This time series contains several environmental (e.g., winter severity) and biological (e.g., predator abundance) signals that can be used to disentangle multiple effects on overwinter mortality of these fishes. A multiple regression analysis indicated that age-0 yellow perch winter mortality was inversely related to fish length in autumn and to the abundance of alternative prey (gizzard shad [Dorosoma cepedianum] and white perch). However, no length-selective predation of yellow perch by one of the main predators, adult walleye (Sander vitreus), was detected. In contrast, white perch mortality was directly associated with total predator biomass and abundance of white perch in autumn, and inversely related to yellow perch abundance as a potential buffer species, but not to the abundance of gizzard shad. Winter severity was not a significant predictor of mortality for either perch species. Predicted winter starvation mortality, from a model described in the literature, was much lower than observed mortality for yellow perch. Similar models for white perch were correlated with observed mortality. These results collectively suggest that predation is the main mechanism shaping winter mortality of yellow perch, while both predation and starvation may be important for white perch. This analysis also revealed that gizzard shad buffer winter mortality of yellow perch. Although winter duration determines the northern limit of fish distributions, in mid-latitude Oneida Lake and for these species, predator-prey interactions seem to exert a greater influence on winter mortality than starvation.

Aging↗
PubMed1999

Ability of laying hens to jump between perches: individual variation and the effects of perch separation and motivation on behaviour.

1. This study investigated the ability and the behaviour of laying hens jumping between perches 2 different distances apart using hungry and satiated birds to determine whether behaviour and success were related to motivation. 2. Four groups of 10 birds (Lohmann brown) trained to jump from one perch to another were subjected 4 times to each of the experimental treatments (2 perches with a distance of either 50 or 150 cm between them) whilst either hungry or satiated, controlling for time of day and order of presentation. 3. The behaviour of each bird on the 1st perch was observed for a maximum of 2 min or until the bird jumped from the perch. The outcome of each jump, number of head movements and steps, incidence and duration of calling, and activity score were recorded. 4. The probability of birds jumping was less at the greater distance and was not affected significantly by other experimental factors. 5. Head movements were more frequent in birds which jumped, at the shorter distance, in motivated (hungry) birds and in the morning rather than the afternoon. 6. More stepping was performed by birds which jumped and at the shorter distance; there was no significant effect of motivation or time of day on stepping rate. 7. Birds called more at the greater distance and this was interpreted as indicative of frustration. 8. Subjective scores for activity were lower when perches were separated by the greater distance and when birds were satiated (less motivated) rather than hungry. 9. Agitated head movements and stepping activity thus occurred mainly when birds were motivated and on the point of jumping whereas calling was associated with an apparent inability or unwillingness to jump.

Animals↗
PubMed1999

Enteric helminths of perch (Perca fluviatilis L.) and yellow perch (Perca flavescens Mitchill): stochastic or predictable assemblages?

Component communities of perch (Perca fluviatilis L) in Eurasia and the North American yellow perch (Perca flavescens Mitchill) were examined to determine the nature of their parasite communities. The scale of this investigation is continental and includes data collected across the distribution of each host species. Data were compiled from the literature and from 5 sample sites in North America. Four parasite species were found to occur frequently in the helminth component communities of P. flavescens. The cestodes Bothriocephalus cuspidatus and Proteocephalus pearsei, the digenean Crepidostomum cooperi, and the nematode Dichelyne cotylophora comprised a suite of species of which some or all occurred in most samples. Similarly, a group of 4 predictable parasite species was identified for P. fluviatilis in Eurasia, the digenean Bunodera luciopercae, the nematode Camallanus lacustris, the cestode Proteocephalus percae, and the acanthocephalan Acanthocephalus lucii. Specificity was not a requirement for predictability. Despite geographical isolation for millions of years, and different fish species interactions within and between continents, the predictability of these parasite assemblages indicates they are shaped by a biology, especially feeding patterns, common to both perch species. This is evidence that parasite assemblages comprised of nonhost-specific parasites in freshwater fishes are not merely stochastic assemblages but have key components that are predictable at this broad continental scale.

Animals↗
PubMed1998

Factors affecting the use of perches in cages by laying hens.

1. Three experiments were carried out with ISA Brown laying hens housed in individual cages with softwood perches of rectangular cross section fitted across the width of each cage, to investigate factors affecting the tendency of hens to lay their eggs from the perches and to use perches at other times. These factors were perch width and angle and method of perch introduction. 2. In experiment 1 there were 4 treatments. Perches were 38 or 60 mm wide; half of each width were flat and half were fixed at 8 degrees, parallel to the slope of the floor. In 2 similar trials (with 48 and 44 birds respectively, equally divided between treatments) birds were moved to experimental cages already fitted with perches. Birds with 38 mm, sloping perches laid less than one third of their eggs from the perch (31% and 9% in the two trials) while those with the other designs laid more than 80% from the perch. Narrow sloping perches were not otherwise aversive and there was no consistent variation between treatments in total time perching. 3. In experiment 2, 32 birds were allowed to start laying on the floor of the experimental cages then perches were introduced at 24 weeks with 8 birds on each of 4 treatments: 50 mm perches fixed flat and 38 mm perches fixed flat, and at 5 and 10 degrees respectively. Only 27% of eggs were laid from the perches with no variation between treatments either in this behaviour or in total time perching. 4. Experiment 3 provided 24 of the birds from experiment 2 with double-length perches to determine whether they showed preferences for the design features under consideration. Either half the perch length was flat and half sloping at 10 degrees or half was 38 and half 50 mm wide. Again a relatively low proportion of eggs was laid from the perches (18%) and birds showed no significant preference for different perch designs as indicated by either how much they perched or where they perched. 5. These results suggest that both perch design and the way pullets are introduced to perches influence the proportion of perch-laid eggs. They confirm that in some circumstances laying from perches can be a serious problem, but that in other circumstances incidence can be reduced to a manageable frequency. Perches may therefore be practical in commercial production without increasing the number of cracked eggs. The results are also likely to be applicable in cages with other facilities including nest boxes.

Animals↗
PubMed2001

Effects of density on perching behavior of broiler chickens.

Exercise through perching has been suggested as a way to reduce the impact of leg problems in broiler chickens. It is possible that higher stocking densities may motivate birds to perch more, and perhaps reduce some of the detrimental effects to broiler health seen with high stocking densities. The goal of this research was to investigate the effects of density (10, 15, and 20birds/m(2)) and perch design on the frequency of perch utilization. Mixed sex broilers were assigned to 36 pens in a four perch treatmentxthree density factorial with three replications for each treatment/density combination in a randomized complete block design. Pens were assigned to one of four perch treatments: control (no perches), horizontal (three horizontal perches), angled (three 10 degrees angled perches), or mixed angle (one horizontal, one 10 degrees angled, and one 20 degrees angled perch), at each of the three densities. The results show that although the frequency of perch use was low, (2.6%+/-0.15), significant preferences were clear. Perching frequency was significantly higher when birds were raised at stocking densities of 15 (2.88+/-0.303) or 20birds/m(2) (2.76+/-0.211), as opposed to 10birds/m(2) (2.10+/-0.209) as indicated by a marginally significant main effect (p<0.0597), and a significant linear effect (P<0.0427). The birds used the horizontal perches the most, followed by 10 degrees angled and mixed angle perch treatments with decreasing frequency. An effect of age was found, in that perching increased during the first 4 weeks, and dropped off significantly at the end of the rearing period for all perch treatments. In general, perches closest to the hallway or outside of the house were used more than perches in the middle of the pen. Preferential use of the highest section of the 10 degrees angled perches was also found. The applied perch treatments or densities did not significantly affect final body weight or feed conversion. Percent mortality due to heat stress showed a significant increase with density, while mortality not caused by heat stress did not change with perch treatment or density.

Journal Article↗
PubMed2002

Use of cool perches by broiler chickens.

Broilers under commercial conditions might experience relatively high temperatures during summer and leg disorders year round that may be partially alleviated by providing them with access to cooled perches. It is unknown, however, how perch temperature and factors such as height and position of the perch affect perch use. Furthermore, little is known regarding gender effects. Eight thousand 1-d-old, mixed-sex broilers were exposed to three perch treatments to determine preferences for water-cooled perches over ambient temperature perches and preferences for height, location, and temperature section of the perch. The experimental treatments were as follows: 1) three cool perches 15 cm above the floor (Cool 15), 2) three ambient perches 7.5 cm off the floor (Ambient 7.5), 3) three ambient perches 15 cm high (Ambient 15), and 4) control chambers with no perches. Total number of birds perching, their positions, and temperature section within the perch were recorded. The results indicate a strong preference for high perches as birds grow (P < 0.0001). The cooler sections of the perch were utilized more than warmer sections within the cool treatments (P < 0.05). Females showed a stronger tendency to perch than males, particularly within the cool treatment (P < 0.0001). The higher perch use could be one of the reasons for the higher eviscerated body weight found in females with access to cool perches (P < 0.05). Differences in mean body weight were not significant (P = 0.07). Potential beneficial effects of perch access in final body weights needs to be further investigated.

Age Factors↗
PubMed1992

Individual perching behavior of laying hens and its effects in cages.

1. ISA Brown hens were housed, from 18 to 71 weeks of age, as groups of 4 in cages with 675 cm2/bird. There were 7 treatments: control cages and 6 treatments with perches fitted across the rear of the cage. Five treatments had 450 mm wide cages, with perches made from hardwood, textured metal, smooth plastic, softwood and padded vinyl, and one treatment had a 600 mm wide cage, with a softwood perch. There were 4 cages in each of the first 6 treatments and 6 in the last. 2. Overall, birds spent about 25% of the day time on perches. Most time (28 to 41%) was spent perching on the 600 mm softwood perches. Among 450 mm perches, most time (25 to 30%) was spent on the softwood perch and least (13 to 23%) on the plastic; the results suggested that a slightly rough surface was preferred. Individual birds varied considerably in the proportion of day time they spent perching; this variation was relatively consistent over time. 3. Overall, the proportion of birds roosting on the perches at night was 85% in period 1; declined to 76% by period 6, probably because increased body size made it almost impossible for 4 birds to perch in the 450 mm cages. Birds roosting on the floor tended always to be the same individuals. 4. Damage to the soles of the feet was less in all treatments with perches than in control cages. It was least in 600 mm wide cages and showed a negative correlation with time spent perching, both within and between treatments. Long or twisted claws, in contrast, tended to be slightly worse in treatments where there was most perching. 5. Downgraded eggs tended to be slightly more frequent in cages with perches; the greatest proportion (cracked 1.4%, dirty 3.6%) was from the 600 mm wide cages, as a result of hens laying from the perch and a build-up of manure behind it. 6. Although problems remain the findings suggest that provision of perches is important for the welfare of hens; perch space should be sufficient to allow all birds to perch simultaneously.

Age Factors↗
PubMed2000

Night-time roosting in laying hens and the effect of thwarting access to perches.

Free-living hens roost on branches in trees at night, and laying hens in aviary systems or cages provided with perches also make extensive use of these for night-time roosting. It is therefore suggested that roosting on perches is important to the hens and that domestic hens should be provided with perches in order to promote welfare. However, no study has addressed the question of motivation for roosting. In the present experiment, we studied undisturbed roosting behaviour and the reaction of commercial laying hens when roosting on perches was thwarted. Fifty-two adult hens (Lohmann Selected Leghorn, LSL) were kept in two groups of 26 hens in litter pens with perches at heights of 23, 43 and 63 cm. Behaviour was observed for 60 min starting at lights-off, registering the number of hens on each perch level. The hens started to get onto the perch immediately and within 10 min after lights-off, more than 90% of the hens were on the perch. All hens roosted close together on the top perch. In a second experiment, 24 hens were kept in eight groups of three birds each in experimental pens equipped with perches. Birds were tested in four different situations: (1) the pen unchanged (Base), (2) the perch covered with plexiglass (PCov), (3) the perch removed (PRem) and (4) the unchanged pen (Post). The order of PCov and PRem alternated between groups in a balanced manner and all groups of birds experienced all four treatments. The hens were observed for 60 min from lights-off using focal sampling. For comparisons, the Post treatment served as the control. In the treatments where perching was not possible, the hens spent less time sitting (p=0.042), and also tended to spend more time standing (p=0.06), than in the control. Furthermore, the hens moved more (p=0.042) when the perch was inaccessible, and when the perch was visible but inaccessible they also showed more attempts to take off (p=0.042). These findings can be interpreted as increased frustration and/or exploration, probably to find an alternative roosting site. Together with the high use of perches for night-time roosting under undisturbed conditions, these results indicate that laying hens are motivated to perch and imply that hens kept under conditions where perching is not possible may experience reduced welfare.

Journal Article↗
PubMed1997

Ability of laying hens to negotiate horizontal perches at different heights, separated by different angles.

1. This paper describes how birds move between horizontal perches at different heights with different angles separating them, using the time to complete the task and the number of birds failing to indicate ability. 2. For the first experiment, 4 groups of 15 birds (ISA Brown) were subjected to each of the experimental treatments (using three perches with angles of 0 degree (horizontal control), 30 degrees, 45 degrees or 60 degrees between them). The birds were required to move upward between the perches for each treatment and then to move downward between the perches, as a second part of the experiment. 3. Birds moving up between the perches took significantly longer at 60 degrees than at any other angle. No birds failed to complete the task. 4. For birds moving downward between the perches, the median time to complete the task increased significantly with angle. Furthermore, the number of birds failing to complete the task increased with angle. 5. A second experiment was conducted to test whether the vertical or horizontal component of distance affected birds' ability to negotiate perches separated by different angles. 6. For the second experiment 4 groups of 10 Lohmann Brown laying hens were subjected to each of the following treatments: two horizontal perches separated by 30 degrees or 60 degrees and either directly, horizontally or vertically separated by a set distance of 50 cm. Birds were required to move both up and down between perches. 7. Birds negotiated horizontally-separated perches more successfully at 30 degrees than at 60 degrees. However, when the vertical distance between the perches was 50 cm there was no significant difference in the ability of birds to move downward at 30 degrees or 60 degrees. For birds moving upward, 60 degrees was easier to negotiate than 30 degrees. 8. The vertical and horizontal separations, as well as the different angles affected the ability of birds to move between perches. There was a general decreasing trend in ability with increasing vertical separation between perches. 9. The findings are important in terms of arrangements of perches to improve bird welfare. To minimise the risk of injury, the angle between perches at different heights should be no more than 45 degrees, and the horizontal and vertical distances between these perches minimised, to allow the birds to be able to move downwards more easily.

Animal Welfare↗
PubMed2001

Group size and perching behaviour in young domestic fowl.

To test the hypothesis that young domestic fowl perform less perch-related antipredator behaviour with increasing group size, White Leghorn pullets were reared in four replicate groups of 15, 30, 60 and 120 at a constant density of 5 birds/m(2). Each pen contained perches 20, 40 and 60cm above the ground. Perch space per bird per perch level was the same for all groups. It was predicted that, with increasing group size, domestic fowl would (1) spend less time on perches (i.e. more time down on the floor); (2) be less vigilant while perching; (3) spend relatively more time preening down on the floor. As predicted, the proportion of 3- to 18-week-old birds roosting on perches during scans throughout the photoperiod decreased with increasing group size, from 41+/-1.7% in groups of 15 birds to 33+/-1.6% in groups of 120 birds. This effect was due to reduced use of the lower perches; use of the highest perches was high at all group sizes. The proportion of birds vigilant on the highest perches of those present on that perch level decreased with increasing group size. The proportion of birds engaged in the vulnerable activity of preening down on the floor increased with group size. The frequency of transitions between floor and perches was not affected by group size but birds received more disturbances from other birds when on the top perch level in the larger groups. Thus, the decline in vigilance on the top perch level with increasing group size was not due to reduced disturbance from other birds. In conclusion, despite domestication and protection from non-human predators, changes in the use of perches by young domestic fowl with increasing group size were consistent with the antipredator hypothesis.

Journal Article↗
PubMed1991

Performance evaluation of heat-stressed commercial broilers provided water-cooled floor perches.

A study was conducted to determine whether water-cooled floor perches would be utilized by commercial broilers exposed to a constant hot ambient environment; and subsequently, whether utilization of these perches would improve performance beyond those provided uncooled floor perches. A total of 330 day-old commercial broiler chicks were randomly allocated to six pens (2.44 m2) in an environmentally controlled facility and maintained in a thermoneutral brooding environment for 16 days. Following this period, 240 birds were selected on a body weight basis and randomly assigned to the six pens. A perch constructed from steel pipe (2.44 m length, 5.0 cm diameter) was then placed diagonally on the litter covered floor of each pen. The birds were first exposed to a thermoneutral period (27.7 C), during which time cooling of the perches in three replicate pens was initiated by circulating tap water. The other three experimental pens received ambient perches. Ambient temperature was then raised to 32.6 C for the following 4 wk. The results of the present study showed that utilization of water-cooled perches by broilers was greater (P less than or equal to .01) than ambient perch utilization throughout the 32.6 C period. Average daily gain was greatest (P less than or equal to .01) for broilers exposed to cool perches. Additionally, they consume more feed (P less than or equal to .05), on a daily basis, than those given ambient perches during the heat-stress period. Broilers exposed to water-cooled perches also had a more efficient gain to feed ratio (P less than or equal to .01). At the completion of the study, final body weight and total body weight gain were greater (P less than or equal to .05) for broilers given water-cooled perches compared with those exposed to ambient perches. Total amount of feed consumed and total feed efficiency were only moderately affected (P less than or equal to .10) by perch treatments. These results indicated that water-cooled perches were beneficial in improving broiler performance during periods of high environmental temperatures.

Animals↗
PubMed2001

High summer concentrations of mercury in big perch (Perca fluviatilis L) from the Tvärminne archipelago (SW Finland) and Nåtö (Aland Islands) Baltic sea.

During high summer seasons in 1994-1999 84 big (20-42 cm total length) female perch (Perca fluviatilis L) were sampled from the waters around Tvärminne Zoological Station on the Hanko-Hangö peninsula on the SW coast of Finland for mercury analysis. Additional sampling of 13 big female perch during the same season were carried out from the waters of Nåtö Biological Station on the Aland Islands in 1997-1998. High summer is the most important season for perch fishing and consumption not only for private families during leisure time but also for professional fishery including trade and export, processing and preparations for restaurants. Fillets of big specimen of perch, s.c. "fillet perch" or "sea perch" from outer coastal waters were chosen for the study to find out the levels of mercury concentration in these desirable fish. The mean concentration of mercury in the dorsal muscle tissue (fillet) of big female "sea perch" from the coastal waters of Tvärminne Zoological Station was calculated to 0.22 (SD 0.08), range 0.08-0.43 mg/kg, f wt and for big female perch from the waters of Nåtö Biological Station to 0.18 (SD 0.07), range 0.07-0.30 mg/kg, f wt respectively. The results show a considerably lower mercury level in big "fillet perch" caught from the outer coastal waters in both Finland (and Estonia) compared with the levels recorded of big "fillet perch" from fresh water lakes and reservoirs. Thus, the common expression "sea perch" may also be used in the form "Baltic sea perch" meaning big healthy perch with low concentrations of mercury and caught from the outer coastal waters in S and SW Finland (and W Estonia) when marketing perch for human consumption.

Animals↗
PubMed2005

Risk-taking behaviour in foraging young-of-the-year perch varies with population size structure.

I investigated if risk-taking behaviour of young-of-the-year (YOY) perch Perca fluviatilis was connected with population-specific predation patterns in four lakes in northern Sweden. The lakes differ in perch size distribution, according to earlier fishing surveys. Thus, the most intense predation pressure by cannibals is assumed to occur at different prey-size windows in the four lakes. In an aquarium study, I observed groups of perch, and registered time spent foraging in an open habitat and number of prey attacks in the presence of a predator. Perch from Angersjön, with the highest proportion of large fish in the population, spent more time in the open area than those from Fisksjön that has a dense population of mainly small perch. The Angersjön perch also made more prey attacks than did perch from Fisksjön and Bjännsjön. Relative differences in predation risk in the four lakes were estimated as cannibalistic attack rates, on a range of sizes of YOY perch, calculated from population size distributions. Principal component analysis on predation risk patterns resulted in two components, of which PC1 explained 79.1% of the variation. High scores of PC1 indicated low cannibalistic attack rates on smaller perch (10-20 mm) and high rates on larger fish (> or =30 mm), while low scores indicated the opposite. The level of risk-taking behaviour in the aquarium study positively correlated with lake-specific PC1 scores. The perch with the most cautious behaviour in the aquaria originated from the population with the highest predation pressure on early stages. The boldest perch came from the lake with low predation on the smallest, but with higher predation on larger YOY perch. Thus, the influence of predation risk on behaviour patterns in perch may depend on the timing of the highest exposure to predators.

Animals↗
PubMed2004

Breast blisters in groups of slow-growing broilers in relation to strain and the availability and use of perches.

1. The relationship between perching behaviour, availability of perches and the incidence and severity of breast blisters in broilers was investigated together with a comparison between two slow-growing broiler strains. 2. Sixteen single strain groups (n = 60) of Labresse and i657 broilers were subjected throughout the experiment to one of three perch availabilities: 15 cm per bird (Labresse and i657), 7.5 cm per bird (i657 only), and 0 cm per bird (i657 only) with 4 replicates per treatment. The birds were housed indoors from one day old, and at 43 d of age 52 birds from each group were moved to outdoor housing facilities with access to grass-covered outdoor areas until slaughter at 84 d of age. 3. The use of perches was monitored via video recordings throughout the experimental period. The severity of breast blisters was recorded on a scale from 0 to 2 at slaughter. 4. Groups of i657 with 15 cm perch per bird used these more than groups with 7.5 cm perch per bird (19% vs 8% of birds perching at midnight). A positive association between access to perches and severe breast blisters (score 2) was found in the groups of i657, with odds ratios of 3.1 and 3.4 for 7.5 and 15.0 cm per bird, respectively, relative to the no-perch treatment. 5. Labresse were more likely to develop breast blisters than i657 (odds ratio 3.5), but used the perches less (0.1 vs 9.5 birds perching at midnight) and weighed less (2011 g vs 2246 g) than i657. 6. Males had a higher incidence of breast blisters than females (odds ratio 12.2), and this was most prominent in the Labresse strain (odds ratio 40.0). 7. In some broiler strains access to perches may be associated with an increase in the occurrence of severe breast blisters, but strain and sex of broiler chickens appear to have a much larger influence than access to perches on the incidence of breast blisters.

Animals↗