The feeding ecology and field energetics of the Pedra Branca skink (Niveoscincus palfreymani)

2003 ◽  
Vol 30 (1) ◽  
pp. 81
Author(s):  
Nigel Brothers ◽  
Alan Wiltshire ◽  
David Pemberton ◽  
Nick Mooney ◽  
Brian Green
Keyword(s):  
Feeding Ecology ◽  
Endemic Species ◽  
Water Exchange ◽  
Turnover Rates ◽  
Free Living ◽  
Isotope Turnover ◽  
Important Prey ◽  
Fish Remains

The diet and food requirements of free-living Pedra Branca skinks (Niveoscincus palfreymani) were studied on Pedra Branca Island, the only known location for this vulnerable, endemic species. While discarded fish remains and regurgitate from seabirds are utilised as food by the skinks during summer, invertebrates represent the most important prey. Isotope turnover rates indicate that feeding is negligible over winter and that significant amounts of non-food water are turned over during summer, either by drinking rainwater or as pulmo-cutaneous water exchange. An assessment is made of the seasonal and annual food requirements of individual skinks and the population.

Feeding ecology of free-living nematodes.

2021 ◽  
pp. 185-215
Author(s):  
Nabil Majdi ◽  
Tom Moens ◽  
Walter Traunspurger
Keyword(s):  
Feeding Ecology ◽  
Trophic Interactions ◽  
Feeding Habits ◽  
Food Sources ◽  
Environmental Constraints ◽  
Feeding Rates ◽  
Feeding Selectivity ◽  
Free Living ◽  
Aquatic Nematodes ◽  
Food Recognition

Abstract This chapter provides overview of the feeding habits and food sources of aquatic nematodes. The environmental constraints on feeding, food recognition, and feeding selectivity are also addressed, together with the complex, indirect trophic interactions between nematodes and their microbial prey. To raise awareness of the inherent methodological and/or interpretational problems in studies of nematode feeding ecology, the chapter ends with a brief look at the methods that have been adapted to quantify feeding rates in nematodes.

Tissue-specific isotope trophic discrimination factors and turnover rates in a marine elasmobranch: empirical and modeling results

2012 ◽  
Vol 69 (3) ◽  
pp. 551-564 ◽  
Author(s):  
Luis Malpica-Cruz ◽  
Sharon Z. Herzka ◽  
Oscar Sosa-Nishizaki ◽  
Juan Pablo Lazo
Keyword(s):  
Natural Populations ◽  
Nitrogen Isotope ◽  
Cartilage Tissue ◽  
Turnover Rates ◽  
Isotopic Equilibrium ◽  
Isotope Turnover ◽  
Discrimination Factors ◽  
Triakis Semifasciata ◽  
Leopard Sharks ◽  
Trophic Discrimination

There are very few studies reporting isotopic trophic discrimination factors and turnover rates for marine elasmobranchs. A controlled laboratory experiment was conducted to estimate carbon and nitrogen isotope trophic discrimination factors and isotope turnover rates for blood, liver, muscle, cartilage tissue, and fin samples of neonate to young-of-the-year leopard sharks ( Triakis semifasciata ). Trophic discrimination factors varied (0.13‰–1.98‰ for δ13C and 1.08‰–1.76‰ for δ15N). Tissues reached or were close to isotopic equilibrium to the new diet after about a threefold biomass gain and 192 days. Liver and blood exhibited faster isotope turnover than muscle, cartilage tissue, and fin samples, and carbon isotopes turned over faster than those of nitrogen. Metabolic turnover contributed substantially to isotopic turnover, which differs from most reports for young marine teleosts. We modeled the relationship between muscle turnover rates and shark size by coupling laboratory results with growth rate estimates for natural populations. Model predictions for small, medium, and large wild leopard sharks indicate the time to isotopic equilibrium is from one to several years.

The diet of southern elephant seals (Mirounga leonina) from Heard Island

1995 ◽  
Vol 73 (8) ◽  
pp. 1519-1528 ◽  
Author(s):  
David J. Slip
Keyword(s):  
Stomach Contents ◽  
First Year ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Important Prey ◽  
Heard Island ◽  
Southern Elephant Seals ◽  
Beaked Whales ◽  
Fish Remains ◽  
Dissostichus Eleginoides

Stomach contents were lavaged from 76 southern elephant seals (Mirounga leonina) at Heard Island between July 1992 and March 1993. Eighty-six percent of stomachs contained cephalopods of 17 species. Numerically the most important was Psychroteuthis glacialis (21.1%), and from estimated biomass the most important was Kondakovia longimana (40.4%). Three other species were also common prey: Moroteuthis knipovitchi (19.4% by estimated biomass), Moroteuthis ingens (13.0%), and Alluroteuthis antarcticus (10.2%). Sixty-six percent of stomachs contained fish remains, and four species, Dissostichus eleginoides, Electrona carlsbergi, E. antarctica, and Gymnoscopelus nicholsi, were identified from otoliths. The diet of adults differed from that of juveniles, particularly pups in their first year. Martialia hyadesi was the most important prey of juveniles and represented 57.1% of estimated biomass consumed. Furthermore, smaller seals ate smaller squid. The species and size of cephalopods eaten by southern elephant seals are similar to those of other Southern Ocean predators, particularly some beaked whales.

Feeding Ecology of the Whiskered Tern, Chlidonias-Hybrida, in the Alligator Rivers Region, Northern-Territory

1989 ◽  
Vol 16 (5) ◽  
pp. 549 ◽  
Author(s):  
PL Dostine ◽  
SR Morton
Keyword(s):  
Feeding Ecology ◽  
Dry Weight ◽  
Northern Territory ◽  
Sexual Differences ◽  
Small Fish ◽  
Important Prey ◽  
Whiskered Tern ◽  
Invertebrate Animals ◽  
Chlidonias Hybrida

Prey from stomachs of 55 whiskered terns collected on a freshwater floodplain in the monsoonal Northern Territory were identified and counted. The terns ate a wide variety of invertebrate animals, most of them aquatic or with aquatic affinities. The most important prey in terms of dry weight were small fish, particularly Eleotridae, and insects, particularly Coleoptera, Odonata and Hemiptera. Vertebrates constituted 51% by dry weight of the diet. Numerically, dominant groups were Coleoptera, Odonata and small fish. Sexual differences were evident in morphology and diet. Males were heavier, had longer bills and wider gapes, and consumed more fish; females ate more invertebrates.

Review of Data on Diets of Beaked Whales: Evidence of Niche Separation and Geographic Segregation

2003 ◽  
Vol 83 (3) ◽  
pp. 651-665 ◽  
Author(s):  
C.D. MacLeod ◽  
M.B. Santos ◽  
G.J. Pierce
Keyword(s):  
Prey Species ◽  
Stomach Contents ◽  
Published Data ◽  
Niche Separation ◽  
Beaked Whale ◽  
Important Prey ◽  
Wide Range ◽  
Dietary Niche ◽  
Beaked Whales ◽  
Fish Remains

This study reviewed published data on dietary preferences of beaked whales (Ziphiidae) from stomach contents analysis. Detailed data were only available for three of the six beaked whale genera (Hyperoodon, Mesoplodon and Ziphius). Stomach samples of these three beaked whale genera primarily contained cephalopod and fish remains, although some also contained crustaceans. Mesoplodon spp. were found to contain the most fish, with some species containing nothing but fish remains, while the southern bottlenose whale (Hyperoodon planifrons) and Cuvier's beaked whale (Ziphius cavirostris) rarely, if ever, contained fish. Of cephalopods identified, Histioteuthid, Gonatid, Cranchiid and Onychoteuthid species usually contributed most to prey numbers and biomass for all beaked whale genera. There was a wide range of species and families of cephalopods recorded from stomach contents, with no obvious preference for bioluminescent prey species, vertical migrating prey species or prey species with specific body compositions. Whales of the genus Mesoplodon generally contained smaller prey, such as cephalopods under 500 g in weight, compared with other beaked whales. Hyperoodon and Ziphius frequently contained much larger cephalopods with many important prey species having a mean weight of over 1000 g. This suggests that Mesoplodon occupies a separate dietary niche from Hyperoodon and Ziphius, which may be an example of niche segregation. In contrast, Hyperoodon and Ziphius appear to occupy very similar dietary niches but have geographically segregated distributions, with Hyperoodon occupying cold-temperate to polar waters and Ziphius occupying warm-temperate to tropical waters.

Variation in Water Turnover by Wild Rabbits, Oryctolagus cuniculus, in an Arid Environment, due to Season, Age Group and Reproductive Condition

1979 ◽  
Vol 6 (3) ◽  
pp. 289 ◽  
Author(s):  
GC Richards
Keyword(s):  
Arid Environment ◽  
Summer Drought ◽  
Age Group ◽  
Turnover Rates ◽  
Reproductive Condition ◽  
Water Turnover ◽  
Free Living ◽  
Dry Seasons ◽  
Individual Rate ◽  
Wet And Dry Seasons

Rates of water turnover were measured in free-living rabbits during a period of wide variation of climate and water availability. Mean rate of water turnover was positively correlated with the hydration of the pasture (r = 0.987). Mean turnover rates per day ranged from 214.3 ml kg-1 in cool, wet conditions to 55.4 ml kg-' in a moderate summer drought. The lowest individual rate was 46.1 ml kg-1 per day. The rate of water turnover in young rabbits (1-2 months old) was significantly higher than that of adults measured at the same time; this may contribute to the low survival of young rabbits in dry seasons. A comparison of the rates of water turnover from lactating rabbits in wet and dry seasons shows that the estimated milk production under dry pasture conditions is below that required to maintain a litter of young.

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