Fish feeding groups, food selectivity, and diet shifts associated with environmental factors and prey availability along a large subtropical river, China

2019 ◽  
Vol 81 (2) ◽  
Author(s):  
Sai Wang ◽  
Jin-Peng Tang ◽  
Lin-Hui Su ◽  
Jing-Jing Fan ◽  
Hao-Yen Chang ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Prey Availability ◽  
Food Selectivity ◽  
Fish Feeding ◽  
Feeding Groups ◽  
Diet Shifts

Application of a robust design occupancy model for assessing fish recruitment

2019 ◽  
Vol 76 (4) ◽  
pp. 561-568 ◽  
Author(s):  
Michael J. Weber ◽  
Michael L. Brown
Keyword(s):  
Environmental Factors ◽  
Robust Design ◽  
Prey Availability ◽  
Lepomis Macrochirus ◽  
Water Levels ◽  
Occupancy Model ◽  
Recruitment Failure ◽  
Occupancy Probability ◽  
Fish Recruitment ◽  
Occupancy Detection

Fish recruitment is complex, regulated by environmental factors that induce high mortality early in life. Additionally, age-0 fish can be difficult to sample, making recruitment difficult to detect. We used a robust design occupancy model to evaluate the effects of biotic (age-0 and adult common carp (Cyprinus carpio), bluegill (Lepomis macrochirus), walleye (Sander vitreus), and northern pike (Esox lucius) relative abundance, prey availability, age-0 carp length) and abiotic (water level, temperature) factors on age-0 carp occupancy, detection, and extinction in 13 lakes in South Dakota, USA, for July–April 2008–2010. Age-0 carp occupancy decreased with increasing adult carp abundance and increased with increasing water levels. Age-0 carp detection probability was high during summer (>0.75) but decreased in fall and spring (0.34). Most lakes were occupied in July but overwinter extinction probability was high (59%), resulting in 51% occupancy probability by April. Other environmental factors were not supported, suggesting they had little effect on reproduction and survival. Our results indicate reproduction was universally successful but difficult to detect and that overwinter mortality often resulted in recruitment failure.

scholarly journals Piscivory by Hoplias aff. malabaricus (Bloch, 1794): a question of prey availability?

2013 ◽  
Vol 25 (1) ◽  
pp. 68-78 ◽  
Author(s):  
Ana Karla Araujo Montenegro ◽  
Ana Carolina Brito Vieira ◽  
Maria Marcolina Lima Cardoso ◽  
Jane Enisa Ribeiro Torelli de Souza ◽  
Maria Cristina Crispim
Keyword(s):  
Environmental Factors ◽  
Food Preference ◽  
Prey Availability ◽  
Feeding Habits ◽  
Food Habit ◽  
Spearman Correlation ◽  
Reservoir Volume ◽  
Main Factors ◽  
Selection Of Species ◽  
Selection Of

AIM: In order to understand the factors which influence the predatory activity of the Hoplias aff. malabaricus, the present study evaluated feeding habits of this species and its relation to prey availability, in addition to environmental variables. METHODS: Six samplings were conducted in the Taperoá II reservoir, semi-arid of Paraíba state, Brazil, between October 2005 and October 2006. Measures were taken: rainfall, the reservoir volume, transparency, dissolved oxygen, pH, temperature, nitrate, nitrite, ammonia and phosphate. The activity, diet and feeding habits of H. aff. Malabaricus, from the method of frequency of occurrence of food items and point methods, conjugates in IAI (Alimentary Index). Spearman correlation analysis, a glm and CCA were performed between biotic and abiotic variables, and we used the CPUE as a measure of fish abundance. RESULTS: Eleven taxa of fish were recorded, four of which were predated by adult "trahira". Insects and other items were also common in the stomachs of juveniles. According to statistical analysis, it was observed that the highest consumption of cichlids was correlated with its increase in CPUE in the environment, while no relationship was observed for A. bimaculatus, C. bimaculatum and S. notonota abundances. The environmental factors as nutrients, transparency and water volumn were related to selection of species by trahira. CONCLUSIONS: Intrinsic characteristics of preys as swimming speed, food habit and the food preference of the predator possibly be the main factors to selection of species. Other mechanisms as heterogeneity of habitat and environmental factors can also influence the consumption of prey by trahira

scholarly journals Like clockwork - nest attendance patterns and foraging behaviour of Snares penguins Eudyptes robustus as a function of daylength and oceanography

2018 ◽  
Author(s):  
Thomas Mattern ◽  
Ursula Ellenberg ◽  
David M Houston ◽  
Lloyd S Davis
Keyword(s):  
Environmental Factors ◽  
Foraging Behaviour ◽  
Prey Availability ◽  
Day Length ◽  
Nest Attendance ◽  
Egg Hatching ◽  
Seabird Species ◽  
North East ◽  
Dive Behaviour ◽  
Nesting Patterns

The breeding routines and foraging behaviour of many pelagic seabird species is influenced by environmental factors. Seasonality greatly affects the temporal prey availability for many marine species while the spatial distribution of prey often correlates to oceanographic features. We examined the influence of such environmental factors on the nesting routines and the foraging behaviour of Snares penguins Eudyptes robustus that is endemic to the Snares island group south of New Zealand. Nest attendance and foraging patterns were studied during the incubation stage of three consecutive breeding seasons (2002-2004). Nesting patterns observed in one of the biggest colonies (ca 1200 nest) were highly synchronised, with male penguins leaving the colony to forage within a five-day period around 13 October each year. The males stayed at sea for a mean 11 days before most males returned within a 7-day period around 24-26 October which also marked the main departure period of the females. The females’ foraging trips were considerably shorter and ranged from 5-8 days. The females’ return occurred around the same dates in 2002 and 2003 (late October) but was markedly later in 2004 (early November). Nevertheless, the female’s return was always in sync with egg hatching. Foraging ranges and dive behaviour of six male and two female penguins was examined with GPS dive loggers and time depth recorders. Four of the six males foraged mainly in the cooler waters south of the subtropical front (STF), some 200 km east of the Snares. Dive behaviour of all males indicates primarily travelling behaviour during the first two days at sea. Two males remained in warmer Central Tasman Water (CTW). Movements of three birds determined from GPS suggest that the penguins targeted sea areas with elevated chlorophyll a concentration. Dive behaviour was also related to water mass with dive depths being on average deeper in the cooler waters of the STF. Both females remained only within warmer CTW; temperature data suggests that both birds foraged north to north-east of the island. Dive data indicates that females travelled continuously throughout their trips. The Snares penguin’s foraging behaviour is dictated by oceanic productivity which in turn depends on environmental factors such as day length. Thus, foraging and, consequently, nesting patterns of incubating Snares penguins are also to a great extent a product these factors.

Food selectivity versus prey availability: a study using the marine fish Pomatoschistus microps

Oecologia ◽  
1982 ◽  
Vol 55 (3) ◽  
pp. 311-315 ◽  
Author(s):  
Carin Magnhagen ◽  
Anne-Marie Wiederholm
Keyword(s):  
Marine Fish ◽  
Prey Availability ◽  
Food Selectivity

The influence of prey availability on ontogenetic diet shifts of a juvenile piscivore

2006 ◽  
Vol 63 (8) ◽  
pp. 1722-1733 ◽  
Author(s):  
Tracy L Galarowicz ◽  
Julie A Adams ◽  
David H Wahl
Keyword(s):  
Benthic Invertebrates ◽  
Prey Availability ◽  
Juvenile Fish ◽  
Prey Type ◽  
Ontogenetic Changes ◽  
Foraging Patterns ◽  
Feeding Experiments ◽  
Ontogenetic Diet Shifts ◽  
Predator Foraging ◽  
Diet Shifts

Young-of-year piscivores typically undergo ontogenetic diet shifts from planktivory to benthivory to piscivory. These shifts are often the result of changes in predator foraging abilities, but little is known about the influence of relative prey availability. As a result, we examined diet shifts across a range of sizes (20–150 mm) of a young-of-year piscivore, walleye (Sander vitreus), in feeding experiments in which zooplankton, benthic invertebrates, and fish were made available at different density combinations. Consumption of each prey type changed with walleye size and prey densities. Small juveniles (20 mm) selected zooplankton and fish, whereas larger walleye (40–100 mm) selected benthic invertebrates and fish. Relative prey densities influenced consumption; increased densities of more profitable prey types resulted in reduced consumption of less profitable prey. Walleye larger than 100 mm selected only fish. Foraging efficiencies also varied with size and prey types; small walleye (20 mm) were less likely to pursue benthic invertebrates and retain captured fish. These ontogenetic changes in foraging patterns are linked to prey profitability, have growth consequences for juvenile walleye, and have implications for understanding diet shifts of other juvenile fish.

scholarly journals Mercury and stable isotopes (δ15N and δ13C) as tracers during the ontogeny of Trichiurus lepturus

2013 ◽  
Vol 11 (1) ◽  
pp. 211-216 ◽  
Author(s):  
Ana Paula Madeira Di Beneditto ◽  
Vanessa Trindade Bittar ◽  
Carlos Eduardo de Rezende ◽  
Plinio Barbosa Camargo ◽  
Helena Amaral Kehrig
Keyword(s):  
Prey Availability ◽  
Trophic Position ◽  
Feeding Habits ◽  
World Health ◽  
Fish Feeding ◽  
Feeding Ground ◽  
Eastern Brazil ◽  
Trichiurus Lepturus ◽  
Health Organization ◽  
Δ15n And Δ13c

This study applies total mercury (THg) concentration and stable isotope signature (δ15N and δ13C) to evaluate the trophic status and feeding ground of Trichiurus lepturus during its ontogeny in northern Rio de Janeiro, south-eastern Brazil. The trophic position of T. lepturus is detected well by THg and δ15N as the sub-adult planktivorous specimens are distinct from the adult carnivorous specimens. The δ13C signatures suggest a feeding ground associated with marine coastal waters that are shared by fish in different ontogenetic phases. The diet tracers indicated that the fish feeding habits do not vary along seasons of the year, probably reflecting the prey availability in the study area. This fish has economic importance and the concentration of THg was compared to World Health Organization limit, showing that the adult specimens of T. lepturus are very close to the tolerable limit for safe regular ingestion.

Planktonic invaders of the St. Lawrence estuarine transition zone: environmental factors controlling the distribution of zebra mussel veligers

2003 ◽  
Vol 60 (10) ◽  
pp. 1245-1257 ◽  
Author(s):  
Christine Barnard ◽  
Jean-Jacques Frenette ◽  
Warwick F Vincent
Keyword(s):  
Environmental Factors ◽  
Transition Zone ◽  
Total Phosphorus ◽  
Dreissena Polymorpha ◽  
Prey Availability ◽  
Larval Fish ◽  
Positive Association ◽  
Horizontal Distribution ◽  
Fish Nursery ◽  
Negative Impacts

The St. Lawrence estuarine transition zone (ETZ) is a productive ecosystem supporting a larval fish nursery. Since 1994, Dreissena polymorpha veligers have become the dominant zooplankton (up to 260 individuals·L–1). The environmental factors controlling their distribution across the ETZ and their potential impact on the plankton were determined. Their horizontal distribution was limited by salinity, with maximum decreases in concentration at 2‰. A sharp decline in prey availability at >2‰ may be a secondary stressor for the veligers, in addition to the direct effects of salinity. Their vertical distribution was homogeneous throughout the water column, even in the presence of a pycnocline. Redundancy analysis showed that veliger concentrations were positively correlated with temperature and turbidity and negatively correlated with salinity and total phosphorus. Veligers were also positively correlated with chlorophyll a and picophytoplankton concentrations, suggesting little effect on their phytoplankton prey. Moreover, the veligers were positively correlated with the sestonic ratio of particulate to total phosphorus, indicating their positive association with good food quality. The veligers appear to have no severe negative impacts on the ETZ plankton community and are restricted to favourable conditions for their survival in the upstream, low salinity region of the ETZ.

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