Diet and feeding strategy of the forkbeard Phycis phycis (Pisces: Phycidae) from the Portuguese continental coast

2017 ◽  
Vol 98 (7) ◽  
pp. 1757-1765
Author(s):  
Ana Rita Silva ◽  
Ana Rita Vieira ◽  
Vera Sequeira ◽  
Rafaela Barros Paiva ◽  
Leonel Serrano Gordo ◽  
...  
Keyword(s):  
Feeding Behaviour ◽  
Feeding Strategy ◽  
Prey Group ◽  
Important Prey ◽  
Decapod Crustacea ◽  
Shift Pattern ◽  
The Mean ◽  
Generalist Diet ◽  
Taxonomic Categories ◽  
Phycis Phycis

The diet and feeding behaviour of the forkbeard Phycis phycis was studied based on 246 stomachs collected between May 2011 and April 2012 from a commercial fleet operating off the central west coast of Portugal. A total of 44 prey items were identified in the stomachs which were merged into major groups to avoid problems with low expected frequencies. The following taxonomic categories were considered: non-decapod Crustacea, Caridea, Anomura, Munida spp., Processa spp., Brachyura, Pisces, Trisopterus luscus. In order to investigate possible diet differences between fish size classes, a cluster analysis was performed using the mean abundance of each prey group by forkbeard 5 cm length class, and three length groups (LG) were obtained: <22.5, 27.5–37.5 and >42.5 cm. Seasonally, Caridea was the main prey group during winter and autumn while Pisces was predominant during the rest of the year. Caridea was the most important prey group for LG1 and LG2 while in LG3 Pisces was the principal one. The forkbeard feeding behaviour may be characterized as presenting a shift pattern from a more generalist diet (small Crustacea, mainly Caridea) in the young adults to a more specialist strategy (teleosts) in the adults.

Size-related shift in feeding strategy and prey-size selection in young grayling (Thymallus thymallus)

1996 ◽  
Vol 74 (9) ◽  
pp. 1597-1603 ◽  
Author(s):  
Philippe Sempeski ◽  
Philippe Gaudin
Keyword(s):  
Body Length ◽  
Feeding Behaviour ◽  
Prey Size ◽  
Feeding Strategy ◽  
River Channel ◽  
Large Prey ◽  
Thymallus Thymallus ◽  
Chironomid Larvae ◽  
Size Selection ◽  
The Mean

Observations of feeding behaviour and analysis of prey-size selection by young grayling revealed a shift in feeding strategy coinciding with a shift in habitat occurring between larval (observed in lateral habitats) and juvenile (observed in the river channel) stages of grayling. The mean number of foraging attempts per minute decreased four times between both stages, while in the same time the mean distance travelled during each foraging attempt decreased from 1.5 body lengths to 1 body length. Gape-limited postemergent larvae fed mainly on small chironomid larvae (<0.5 mm3) but larger larvae and pupae (0.5 – 1 mm3) were consumed with increasing size. The diet spectrum of juveniles >40 mm was characterized by the appearance of very large prey (> 10 mm3), such as simuliid and ephemeropteran larvae, but also by a new increase of the contribution of small chironomid larvae. Changes in the feeding strategy of young grayling are discussed in relation to internal (e.g., morphological limitations) and external (e.g., physical characteristics of habitat) constraints.

scholarly journals First data on habitat preference, diet and length-weight relationship of Gobius incognitus Kovačić & Šanda, 2016 (Pisces: Gobiidae)

2020 ◽  
Vol 61 (1) ◽  
pp. 67-78
Author(s):  
Francesco Tiralongo ◽  
Giuseppina Messina ◽  
Bianca Maria Lombardo
Keyword(s):  
Habitat Preference ◽  
Diet Analysis ◽  
Ionian Sea ◽  
Central Mediterranean ◽  
Species Identity ◽  
Weight Relationship ◽  
Important Prey ◽  
Ecological Aspects ◽  
The Mean ◽  
Relationship Of

In this work, we present first data on biological and ecological aspects of Gobius incognitus from specimens from the Ionian Sea (central Mediterranean Sea). In particular, we provided first data on habitat preference, diet and length-weight relationship of G. incognitus on material with confirmed species identity. The species preferred “mixed bottom” (sand and rocks), where it reached relatively high abundances. The diet analysis showed that G. incognitus is a generalist and opportunistic feeder. However, small benthic crustaceans were the most important prey group. The mean total length of specimens was 6.72 ± 1.85 cm and the growth was positive allometric.

Comparison of feeding behaviour and performance of weaned pigs given food in two types of dry feeders with integrated drinkers

1999 ◽  
Vol 68 (1) ◽  
pp. 35-42 ◽  
Author(s):  
M. Laitat ◽  
M. Vandenheede ◽  
A. Désiron ◽  
B. Canart ◽  
B. Nicks
Keyword(s):  
Feeding Behaviour ◽  
Feeding Activity ◽  
Weaned Pigs ◽  
Multifactor Analysis ◽  
Daily Water ◽  
The Mean ◽  
The Difference ◽  
And Performance ◽  
Almost All ◽  
Type V

AbstractPerformance of 80 (tests 1 and 2) or 60 (tests 3 and 4) weaned pigs were compared when using ‘Tubetype’ feeder (T), allowing the animals to mix meal and drinking water, or another type (V) where drinking and eating places are separated. The difference in growth rate was not significant but the mean daily water consumption (1 per pig per day) was higher with T than with V in each test but significantly only in tests 1 and 3 (1·84 v. 1·40, and 2·11 v. 1·26, P < 0·01).Feeding behaviour was assessed during tests 2 and 4. Multifactor analysis of variance revealed effects (P < 0·01) of feeder, group size and period of the day on the occupation time and the average number of animals using the feeders simultaneously. These two variables were higher for V than for T (test 2: 23·4 per 24 h v. 21·5 per 24 h and 4·5 v. 3·7, P < 0·05; test 4: 20·0 per 24 h v. 18·2 per 24 h, P< 0·01). In each test, both feeders were used for a longer time and by more piglets during the ‘day’ than during the ‘night’ (P < 0·01). When grouping 40 pigs, animals used both feeders during almost all the day period (V: 15·9 per 16 h and T: 15·8 per 16 h). During the night period, this was only true with V (V: 7·4 per 8 h; T: 5·8 per 8 h). The use of feeder V in crowded conditions thus prevented preferential diurnal feeding activity, commonly described in pigs. In conclusion, even if productivity is not affected, feeding behaviour and thus eventually welfare are influenced by the type of feeder, especially with high numbers of animals.

Echolocation and feeding behaviour of Taphozous mauritianus (Chiroptera: Emballonuridae)

1980 ◽  
Vol 58 (10) ◽  
pp. 1774-1777 ◽  
Author(s):  
M. B. Fenton ◽  
G. P. Bell ◽  
D. W. Thomas
Keyword(s):  
Long Range ◽  
Feeding Behaviour ◽  
Second Harmonic ◽  
Feeding Strategy ◽  
Rapid Rise ◽  
Constant Frequency ◽  
Insectivorous Bats ◽  
Sound Energy ◽  
Echolocation Calls ◽  
Human Ear

Observations of free-flying bats in the field in Zimbabwe indicated that Taphozous mauritianus uses multiharmonic constant frequency (CF) search calls followed by multiharmonic approach and terminal calls that combine shallow and steep frequency modulated (FM) sweeps during approaches to targets. The three phases of calls all have rapid rise times to full amplitude, and most of the sound energy is in the second harmonic; the fundamental is usually present (11–13 kHz), making the calls clearly audible to the unaided human ear. This combination of characters, but particularly the CF search calls, serves to distinguish these echolocation calls from those of other insectivorous bats. One light-tagged individual hunting insects reacted to targets at distances of about 3 m, suggesting a long-range feeding strategy.

Hard prey specialists or opportunistic generalists? An examination of the diet of the cownose ray, Rhinoptera bonasus

2007 ◽  
Vol 58 (1) ◽  
pp. 135 ◽  
Author(s):  
A. B. Collins ◽  
M. R. Heupel ◽  
R. E. Hueter ◽  
P. J. Motta
Keyword(s):  
Feeding Behaviour ◽  
Stomach Contents ◽  
Relative Importance ◽  
Charlotte Harbor ◽  
Severe Damage ◽  
Important Prey ◽  
Cownose Ray ◽  
Rhinoptera Bonasus ◽  
Group Feeding ◽  
Index Of Relative Importance

Atlantic cownose rays (Rhinoptera bonasus) are benthic, suction feeders whose foraging activities have been implicated in severe damage to commercial shellfish industries. With jaws highly modified for durophagy, it has been assumed that R. bonasus are crushing specialists that feed primarily upon hard molluscan prey. Stomach contents from R. bonasus caught within Florida’s Charlotte Harbor estuary between July 2003 and July 2004 were analysed using the index of relative importance (IRI) to determine most important prey types. Prey items were identified from 38 families and fell into nine distinctive groups. The three most dominant prey groups were crustaceans (%IRI = 55.31), polychaetes (%IRI = 25.20) and bivalves (%IRI = 12.58). Shoalmates had more similar diets than non-shoalmates, suggesting group feeding. Most small or softer-bodied prey consumed were relatively intact, indicating lack of prey processing and capture through suction feeding. All larger, harder-bodied prey showed evidence of crushing (fractured and broken shells). Although R. bonasus has been characterised as a hard prey specialist, these results suggest it may behave as an opportunistic generalist, modifying feeding behaviour to consume readily available prey.

scholarly journals Major oscillations in spontaneous home-cage activity with an infraradian periodicity in C57Bl/6 mice housed under constant conditions

2020 ◽  
Author(s):  
K. Pernold ◽  
E. Rullman ◽  
B. Ulfhake
Keyword(s):  
Spontaneous Activity ◽  
Feeding Behaviour ◽  
Home Cage ◽  
Light Cycle ◽  
Dark Light ◽  
Cage Activity ◽  
Free Running ◽  
The Mean ◽  
Home Cage Activity

AbstractUsing 14-20 months of cumulative 24/7 home-cage activity recorded with a non-intrusive technique and a data driven analytical approach, we here provide evidence for the existence of a circannual oscillation (1-2 SD of the mean, on average 65% higher during peak of highs than lows; P=7E-50) in spontaneous activity of male and female C57BL/6 mice held under constant barrier conditions (dark-light cycle 12/12 h (DL), temperature 21±1°C, humidity 40-60%). The periodicity of the season-like oscillation is in the range of 2-4 months (on average 97 days across cohorts of cages) and off-sets also responses to environmental stimuli but does not significantly alter the preference for activity during the dark hours of this nocturnal mouse strain (P=0.11 difference between highs and lows).The significance of this hitherto not recognized slow rhythmic alteration in spontaneous activity is further substantiated by its co-variation with the feeding behaviour of the mice. The absence of coordination within and between cohorts of cages or synchronization to the seasons of the year, suggests that the oscillation of in-cage activity and behavioural responses is generated by a free-running intrinsic oscillator devoid of synchronization with an out-of-cage environmental time-keeper. Since the variation over time has such a magnitude and correlate with the feeding behaviour it is likely that it will impact a range of long term experiments conducted on laboratory mice if left unrecognized.

scholarly journals Different individual-level responses of great black-backed gulls (Larus marinus) to shifting local prey availability

2021 ◽  
Author(s):  
Laurie Maynard ◽  
Julia Gulka ◽  
Edward Jenkins ◽  
Gail K Davoren
Keyword(s):  
Prey Availability ◽  
Feeding Strategy ◽  
Population Level ◽  
Group Level ◽  
Generalist Species ◽  
Individual Level ◽  
Response Diversity ◽  
Capelin Mallotus Villosus ◽  
Larus Marinus ◽  
Generalist Diet

To grow, survive and reproduce under anthropogenic-induced changes, individuals must respond quickly and favourably to the surrounding environment. A species that feeds on a wide variety of prey types (i.e. generalist diet) may be comprised of generalist individuals, specialist individuals that feed on different prey types, or a combination of the two. If individuals within a population respond differently to an environmental change, population-level responses may not be detectable. By tracking foraging movements of eight great black-backed gulls ( Larus marinus ), a generalist species, we compared group-level and individual-level responses to an increase in prey biomass (capelin; Mallotus villosus ) during the breeding season in coastal Newfoundland, Canada. As hypothesized, shifts in prey availability resulted in significantly different individual responses in foraging behaviour and space use, which was not detectable when data from individuals were combined. Some individuals maintained similar foraging areas, foraging trip characteristics (e.g., trip length, duration) and habitat use with increased capelin availability, while others shifted foraging areas and habitats resulting in either increased or decreased trip characteristics. We show that individual specialization can be non-contextual in some gulls, whereby these individuals continuously use the same feeding strategy despite significant change in prey availability conditions. Findings also indicate high response diversity among individuals to shifting prey conditions that a population- or group-level study would not have detected, emphasizing the importance of examining individual-level strategies for future diet and foraging studies on generalist species.

scholarly journals Feeding habits of the spotted rose snapper, Lutjanus guttatus, (Actinopterygii, Perciformes, Lutjanidae), in the central Gulf of California, BCS, Mexico

2021 ◽  
Vol 51 (1) ◽  
pp. 95-105
Author(s):  
Filius L. Valle-Lopez ◽  
Xchel G. Moreno-Sánchez ◽  
Marina S. Irigoyen-Arredondo ◽  
Leonardo A. Abitia-Cárdenas ◽  
Emigdio Marín-Enríquez ◽  
...  
Keyword(s):  
Gulf Of California ◽  
Trophic Ecology ◽  
Feeding Habits ◽  
Feeding Strategy ◽  
Trophic Niche ◽  
Trophic Plasticity ◽  
Important Prey ◽  
Management Measures ◽  
Reported Study ◽  
Santa Rosalia

The spotted rose snapper, Lutjanus guttatus (Steindachner, 1869), is an important resource for the coastal fisheries of the Gulf of California, mainly due to its high commercial value. Despite this, there are no management measures for this species, owing in part to a lack of information on its basic biology and its trophic ecology in the area. In this context, the presently reported study had as objective to describe the feeding habits of L. guttatus through stomach content analyses, as well as to describe possible changes linked to sex, size, and season. Specimens were caught monthly from June 2016 to September 2017 with gillnets in Santa Rosalía, BCS, Mexico. The abundance, weight, and frequency of occurrence of each prey were assessed, and these parameters were integrated into the index of relative importance (%IRI) to determine the importance of each prey item in the L. guttatus diet. The Levin’s index was used to assess the trophic niche width of the species, the feeding strategy was evaluated using Costello’s graphic method and the trophic level was calculated. Finally, to establish whether there were significant differences in the diet by sex, size, or season a PERMANOVA test was used with a 95% confidence level. A total of 202 L. guttatus stomachs were analyzed, 191 of which contained food. A total of 26 prey items were identified. According to the %IRI, the most important prey were the teleost fishes Harengula thrissina (Jordan et Gilbert, 1882) (45.7%) and Sardinops sagax (Jenyns, 1842) (34.8%), the euphausiid Nyctiphanes simplex (13.4%), and the crustacean Penaeus spp. (5.6%). The PERMANOVA analysis resulted in significant differences between the analyzed categories; however, there were no significant differences in the interactions among the categories. According to Levin’s index, L. guttatus had a narrow trophic width, with changes in the main prey consumed by the different categories. According to our results, L. guttatus can be considered a benthopelagic opportunistic carnivorous predator with a narrow trophic niche, presenting mostly quantitative variations in its diet according to sex, size, and season. Its trophic plasticity allows it to take advantage of the most available and abundant food resources.

The distribution and abundance of electrosensory pores in two benthic sharks: a comparison of the wobbegong shark, Orectolobus maculatus, and the angel shark, Squatina australis

2014 ◽  
Vol 65 (11) ◽  
pp. 1003 ◽  
Author(s):  
Channing A. Egeberg ◽  
Ryan M. Kempster ◽  
Susan M. Theiss ◽  
Nathan S. Hart ◽  
Shaun P. Collin
Keyword(s):  
Similar Pattern ◽  
Feeding Behaviour ◽  
Feeding Strategy ◽  
Gill Slit ◽  
Functional Importance ◽  
Aquatic Animals ◽  
Body Form ◽  
Electrosensory System ◽  
Physiological Adaptations

Electroreception is an ancient sense found in many aquatic animals, including sharks, which may be used in the detection of prey, predators and mates. Wobbegong sharks (Orectolobidae) and angel sharks (Squatinidae) represent two distantly related families that have independently evolved a similar dorso-ventrally compressed body form to complement their benthic ambush feeding strategy. Consequently, these groups represent useful models in which to investigate the specific morphological and physiological adaptations that are driven by the adoption of a benthic lifestyle. In this study, we compared the distribution and abundance of electrosensory pores in the spotted wobbegong shark (Orectolobus maculatus) with the Australian angel shark (Squatina australis) to determine whether both species display a similar pattern of clustering of sub-dermal electroreceptors and to further understand the functional importance of electroreception in the feeding behaviour of these benthic sharks. Orectolobus maculatus has a more complex electrosensory system than S. australis, with a higher abundance of pores and an additional cluster of electroreceptors positioned in the snout (the superficial ophthalmic cluster). Interestingly, both species possess a cluster of pores (the hyoid cluster, positioned slightly posterior to the first gill slit) more commonly found in rays, but which may be present in all benthic elasmobranchs to assist in the detection of approaching predators.

Stream salmonids as opportunistic foragers: the importance of terrestrial invertebrates along a stream-size gradient

2011 ◽  
Vol 68 (12) ◽  
pp. 2146-2156 ◽  
Author(s):  
J. Syrjänen ◽  
K. Korsu ◽  
P. Louhi ◽  
R. Paavola ◽  
T. Muotka
Keyword(s):  
Diet Composition ◽  
Aquatic Invertebrates ◽  
Prey Availability ◽  
Deciduous Forests ◽  
Terrestrial Invertebrates ◽  
Important Prey ◽  
Stream Salmonids ◽  
The Mean ◽  
Forest Streams ◽  
Size Gradient

Terrestrial invertebrates have been reported to be positively selected by stream salmonids. We assessed the importance of terrestrial and aquatic invertebrates to salmonid diets in 25 streams in Finland, with the hypothesis that terrestrial prey would be important in only the smallest forest streams. Several measures of prey availability were used, including proportional abundance in benthic or drift samples, compared with a trait-based approach, to predict diet composition. Across all 25 streams in autumn, blackfly and caddis larvae were the most important prey items. Terrestrial invertebrates were of moderate importance in all streams, including the smallest. Pure availability predicted diet best and provided, in most cases, a significant fit with the observed diet. In a quantitative literature review, the mean proportion of terrestrial prey in salmonid diets was 17%, being highest for the largest fish (≥15 cm). Species of the genus Salmo consumed significantly less terrestrials than did other salmonid genera. The proportion of terrestrial prey was highest in streams flowing through deciduous forests, but it was only weakly correlated with channel width.

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