scholarly journals Spatial niche partitioning among three small cetaceans in the eastern coastal area of Hokkaido, Japan

2020 ◽  
Vol 637 ◽  
pp. 209-223
Author(s):  
Y Iwahara ◽  
H Shirakawa ◽  
K Miyashita ◽  
Y Mitani
Keyword(s):  
Water Depth ◽  
Marine Mammals ◽  
Niche Partitioning ◽  
Niche Overlap ◽  
The Other ◽  
Potential Prey ◽  
Harbor Porpoise ◽  
Prey Distribution ◽  
Marine Predator ◽  
Spatial Niche

Spatial niche partitioning of marine mammals is thought to be caused by dietary differences. However, due to the difficulty involved with conducting simultaneous marine predator and prey distribution surveys at the same scale, marine mammals have not been studied alongside their prey distribution. To understand the spatial niche overlap between 3 small cetaceans observed in the eastern coastal waters of Hokkaido, Japan (Pacific white-sided dolphin Lagenorhynchus obliquidens, Dall’s porpoise Phocoenoides dalli, and harbor porpoise Phocoena phocoena), and the mechanisms behind the differences in their distributions, visual and hydroacoustic surveys using a quantitative echosounder were concurrently conducted. A clear spatial niche overlap was observed between the Pacific white-sided dolphin and Dall’s porpoise, whereas the spatial overlap was moderate between the harbor porpoise and the other 2 species. In areas where Pacific white-sided dolphins were observed, potential prey was abundant in a shallower layer, at approximately 80-90 m depth. On the other hand, potential prey was more abundant in deeper layers in areas where Dall’s and harbor porpoises were observed. Water depth affected the potential prey abundance at all depth layers (0-300 m), as potential prey were more abundant in areas with a shallower water depth. Additionally, potential prey were more abundant in shallower layers (3-200 m) than in deeper layers (200-300 m), where the maximum water depth was 3000 m. The differences in spatial niche among Pacific white-sided dolphin, Dall’s porpoise, and harbor porpoise might cause their dietary differences, as they are epipelagic feeders, midwater feeders, and both epipelagic and midwater feeders, respectively.

Predator and prey detection in two species of water bear (Tardigrada)

2019 ◽  
Vol 188 (3) ◽  
pp. 860-864 ◽  
Author(s):  
Harry A Meyer ◽  
Hannah E Larsen ◽  
Nézira O Akobi ◽  
Garret Broussard
Keyword(s):  
Environmental Conditions ◽  
The Other ◽  
Physical Contact ◽  
Nutrient Agar ◽  
Control Treatment ◽  
Prey Detection ◽  
Potential Prey ◽  
Predator Prey ◽  
Petri Dishes

Abstract Tardigrade behavioural studies have focused on responses to abiotic environmental conditions. Predator–prey interactions have received some attention, but not how predators and prey might detect one another. Here, we investigate whether a predatory tardigrade species is attracted to, and a potential prey tardigrade avoids, areas previously occupied by the other. In our experiments, Milnesium lagniappe was the predator and Macrobiotus acadianus the prey. Petri dishes with non-nutrient agar were used as experimental arenas. In one treatment, we allowed Macrobiotus to roam over half of the agar for 20 h, while leaving the other half free of Macrobiotus. We then removed the prey and introduced the predator. In the control treatment, no prey were added. Results indicated that Milnesium individuals were significantly concentrated in the area previously occupied by Macrobiotus, whereas no such concentration was evident when Macrobiotus had not been present. A similar protocol was used to test whether Macrobiotus avoided areas previously occupied by the predator. As expected, Macrobiotus were significantly concentrated in the area never occupied by Milnesium, unlike the control treatment. These results suggest that both species can detect the other without physical contact and react accordingly. Given that the experiments were conducted in darkness, detection is probably olfactory.

scholarly journals Temporal Variation in the Niche Partitioning of Lake Michigan Salmonines as it Relates to Alewife Abundance and Size Structure.

2021 ◽  
Author(s):  
Benjamin A. Turschak ◽  
Charles R. Bronte ◽  
Sergiusz J. Czesny ◽  
Brandon S. Gerig ◽  
Austin Happel ◽  
...  
Keyword(s):  
Ecological Niche ◽  
Lake Michigan ◽  
Nitrogen Isotopes ◽  
Size Structure ◽  
Prey Availability ◽  
Habitat Preferences ◽  
Niche Partitioning ◽  
Niche Overlap ◽  
Isotopic Niche ◽  
Resource Gradient

Stable isotope analyses offer a useful means for quantifying ecological niche dimensions, though few studies have examined isotopic response of an ecological community with respect to resource gradients such as fluctuations in prey availability. Stable carbon and nitrogen isotopes were measured for Lake Michigan salmonines and their prey collected from 2014 to 2016. Bayesian ellipse and mixing model analyses were used to quantify isotopic niche characteristics and diets, respectively, among species and years. During the three-year study period, abundance and size structure of preferred alewife prey changed substantially and offered an opportunity to explore predator isotopic niche response and diet shifts along a prey resource gradient. Results suggested increased reliance on alewives, especially small alewives, over the study period and were consistent with greater availability of this prey. However, differential use of alewife size classes and alternative prey sources by salmonine predators was apparent, which suggested possible resource partitioning. Characterization of ecological niche overlap using stable isotopes likely requires consideration of shared resource availability as well as specific prey and habitat preferences.

scholarly journals Interactions between frugivorous bats (Phyllostomidae) and Piper tuberculatum (Piperaceae) in a tropical dry forest remnant in Valle del Cauca, Colombia

2016 ◽  
Vol 64 (2) ◽  
pp. 701 ◽  
Author(s):  
Sebastián Montoya-Bustamante ◽  
Vladimir Rojas-Díaz ◽  
Alba Marina Torres-González
Keyword(s):  
Niche Overlap ◽  
Dry Forest ◽  
The Other ◽  
Leg Length ◽  
Wing Area ◽  
Use Of Resources ◽  
Forest Remnant ◽  
Valle Del Cauca ◽  
Artibeus Lituratus ◽  
The Village

Coexistence of species from a trophic guild depends on the division and use of resources. In any ecosystem, fruits are resources that vary in time and space as well as in nutritional content. Therefore, the organisms that depend on them as a food source tend to show a certain degree of specialization. Understanding the factors that influence the dynamics of seed dispersal is important for the regeneration and conservation of tropical ecosystems. Our aim was to determine variation in consumption of <em>Piper tuberculatum </em>(pipilongo) by the fruit bat assemblages in the village of Robles (Jamundí, Valle del Cauca, Colombia). Pipilongo is a resource used not only by wildlife but also by people in the village of Robles. Bats were captured in mist nets between June and November 2014, their feces were collected, and the length of the forearm, wing area, leg length and weight were recorded. At the Universidad del Valle seed laboratory, fecal samples were washed, and their content determined. Of the 14 species captured, <em>Sturnira lilium, Carollia brevicauda, Carollia perspicillata</em> and <em>Artibeus lituratus</em> showed signs of having consumed <em>P. tuberculatum.</em> <em>Sturnira lilium</em> was the main consumer of <em>P. tuberculatum </em>fruits, with the greatest number of consumption events of fruit from this plant species, whereas the other bats showed more diversified consumption events. The greatest niche overlap was recorded between <em>C. brevicauda</em> and <em>C. perspicillata</em>, species that showed similar sizes (i.e., wing area and forearm length) followed by <em>S. lilium</em> and <em>C. perspicillata. </em>In contrast, <em>A. lituratus</em> showed the least niche overlap with the other three fruit bats captured. In conclusion, <em>Sturnira lilium</em> showed an interaction <em>Sturnira-Piper</em>, which is the result of low <em>Solanum</em> availability, and this bat species was the largest consumer of pipilongo in the region.

7. Tidal mixing

2019 ◽  
pp. 98-115
Author(s):  
David George Bowers ◽  
Emyr Martyn Roberts
Keyword(s):  
Water Depth ◽  
Deep Ocean ◽  
Tidal Currents ◽  
The Other ◽  
Tidal Mixing ◽  
Shelf Seas ◽  
Tidal Mixing Front ◽  
Tidal Streams

‘Tidal mixing’ describes tidal mixing in shelf seas, where the water is shallow and tidal currents can be much faster than in the deep ocean. Most of the energy lost from the tide through friction is first converted into turbulence, which then makes a very effective mixing mechanism, stirring the Sun’s heat downwards. Shelf seas at temperate latitudes in summer are divided into stratified regions and vertically mixed regions, depending on the tidal streams’ strength and the water depth. The transition from one to the other happens rapidly and creates a tidal mixing front. Tidal mixing in estuaries is also discussed along with the harnessing of tides to generate electricity.

scholarly journals Resurgence of an apex marine predator and the decline in prey body size

2019 ◽  
Vol 116 (52) ◽  
pp. 26682-26689 ◽  
Author(s):  
Jan Ohlberger ◽  
Daniel E. Schindler ◽  
Eric J. Ward ◽  
Timothy E. Walsworth ◽  
Timothy E. Essington
Keyword(s):  
Life History ◽  
Body Size ◽  
Chinook Salmon ◽  
Marine Mammal ◽  
Marine Mammals ◽  
Size Structure ◽  
Economic Value ◽  
Killer Whales ◽  
Selective Predation ◽  
Marine Predator

In light of recent recoveries of marine mammal populations worldwide and heightened concern about their impacts on marine food webs and global fisheries, it has become increasingly important to understand the potential impacts of large marine mammal predators on prey populations and their life-history traits. In coastal waters of the northeast Pacific Ocean, marine mammals have increased in abundance over the past 40 to 50 y, including fish-eating killer whales that feed primarily on Chinook salmon. Chinook salmon, a species of high cultural and economic value, have exhibited marked declines in average size and age throughout most of their North American range. This raises the question of whether size-selective predation by marine mammals is generating these trends in life-history characteristics. Here we show that increased predation since the 1970s, but not fishery selection alone, can explain the changes in age and size structure observed for Chinook salmon populations along the west coast of North America. Simulations suggest that the decline in mean size results from the selective removal of large fish and an evolutionary shift toward faster growth and earlier maturation caused by selection. Our conclusion that intensifying predation by fish-eating killer whales contributes to the continuing decline in Chinook salmon body size points to conflicting management and conservation objectives for these two iconic species.

scholarly journals Perch Selection by Three Cooccurring Species ofCelithemis(Odonata: Libellulidae): Testing for a Competitive Hierarchy among Similar Species

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Wade B. Worthen ◽  
Parker H. Morrow
Keyword(s):  
Body Size ◽  
Niche Partitioning ◽  
Open Water ◽  
The Other ◽  
Similar Species ◽  
Male Body ◽  
Size Dependent ◽  
Anatomical Characters ◽  
Relative Abundances ◽  
Imagej Software

In many communities of perching dragonflies (Odonata: Libellulidae), a size-dependent competitive hierarchy creates a positive relationship between male body size and perch height. We tested for this pattern among three similar-sized species:Celithemis elisa,C. fasciata, andC. ornata.Males were caught and photographed from May to July 2015 at Ashmore Heritage Preserve, Greenville County, SC, USA, and perch heights and perch distance to open water were measured. Five indices of body size were measured with ImageJ software: abdomen length, forewing length, hindwing length, area of forewing, and area of hindwing.Celithemis fasciatawas significantly larger than the other two species for all five anatomical characters and used perches that were significantly taller and closer to open water than the other species, though these differences changed over the summer. Aggressive interactions between and within species were tallied and compared to expected distributions based on mean relative abundances derived from hourly abundance counts. Patterns of interspecific aggression were also consistent with a size-dependent hierarchy: the largeC. fasciatawas attacked less frequently, and the smallC. ornatamore frequently, than predicted by their relative abundances. We conclude that even small differences in body size may contribute to niche partitioning in perch selection.

scholarly journals Hierarchical influences of prey distribution on patterns of prey capture by a marine predator

2017 ◽  
Vol 31 (9) ◽  
pp. 1750-1760 ◽  
Author(s):  
Gemma Carroll ◽  
Martin Cox ◽  
Robert Harcourt ◽  
Benjamin J. Pitcher ◽  
David Slip ◽  
...  
Keyword(s):  
Prey Capture ◽  
Prey Distribution ◽  
Marine Predator

Development of Method/Apparatus for Close-Visual Inspection of Underwater Structures (Especially Pipelines) in Muddy and Unclear Water Condition

2011 ◽  
Author(s):  
Jasper A. Agbakwuru ◽  
Ove T. Gudmestad ◽  
John G. Groenli ◽  
Helge Skjaveland
Keyword(s):  
Laminar Flow ◽  
Water Depth ◽  
Visual Inspection ◽  
The Other ◽  
The Novel ◽  
Clear Water ◽  
Water Condition ◽  
Initial Stage ◽  
Time Required ◽  
Underwater Structures

Ordinarily, the Remotely Operated Vehicles and underwater divers, even with modern illuminating lamps, would be unable to observe objects clearly in muddy or unclear underwater condition. Efforts have therefore been made to demonstrate that in such underwater condition, it is possible to perform visual inspections and observations adequately and reliably for underwater leaking structures using novel equipment. The novel equipment works by simply supplying a clear laminar flow of water which flows over the surface of the structure to be observed. A camera eye is then placed to observe through the steady flowing clear water. Different configurations of the equipment were checked and it was found that the equipment with fitted valves installed in the flooding box in-line with flowing clear water produced the best result. The volume of water required for the observations appears constant and independent of the depth of water except during the first initial stage of flooding. On the other hand, the period of time required for clear observations increases with increase in water depth. The performance of the equipment was found independent of the nature of underwater visibility. The benefits of this work ranges from leaking structures’ close-visual inspection including leaking pipelines, to subsea pipeline field joint wrap damage inspection for beach pulls in cofferdams. This technique is considered cheap, robust and flexible.

scholarly journals The morphological diversity of Osedax worm borings (Annelida: Siboglinidae)

2014 ◽  
Vol 94 (7) ◽  
pp. 1429-1439 ◽  
Author(s):  
Nicholas D. Higgs ◽  
Adrian G. Glover ◽  
Thomas G. Dahlgren ◽  
Craig R. Smith ◽  
Yoshihiro Fujiwara ◽  
...  
Keyword(s):  
Niche Partitioning ◽  
Three Dimensional ◽  
Morphological Diversity ◽  
Morphological Data ◽  
Micro Computed Tomography ◽  
Fossil Bones ◽  
Spatial Niche ◽  
Multiple Species ◽  
Root Tissues ◽  
Marine Worms

Marine worms in the genus Osedax, have specialized ‘root’ tissues used to bore into the bones of decomposing vertebrate skeletons and obtain nutrition. We investigated the borings of nine Osedax species, using micro computed tomography to quantitatively describe the morphology of the borings and provide three-dimensional reconstructions of the space occupied by Osedax root tissues inside the bone. Each Osedax species displayed a consistent boring morphology in any given bone, but these differed between bones. In bones where multiple species coexisted there was limited evidence for spatial niche partitioning by Osedax root tissues inside the bones investigated here. The new morphological data may be applied to Osedax traces in fossil bones, showing that borings can be used to indicate minimum species richness in these bones.

scholarly journals Seasonal niche differentiation between evolutionary closely related marine bacteria

2020 ◽  
Author(s):  
Adrià Auladell ◽  
Albert Barberán ◽  
Ramiro Logares ◽  
Esther Garcés ◽  
Josep M. Gasol ◽  
...  
Keyword(s):  
Marine Bacteria ◽  
Niche Partitioning ◽  
Environmental Parameters ◽  
Niche Overlap ◽  
Niche Differentiation ◽  
Habitat Filtering ◽  
Coastal Marine ◽  
Class Level ◽  
Nucleotide Divergence ◽  
Selection Of

AbstractBacteria are highly dynamic in marine environments, where they play key biogeochemical roles. Here, we tested how similar the niche of closely related marine bacteria is and what are the environmental parameters modulating their ecological responses in a coastal oligotrophic time series. We further explored how conserved the niche is at broader taxonomic levels. We found that, for certain genera, niche similarity decreases as nucleotide divergence increases between closely related amplicon sequence variants, a pattern compatible with selection of similar taxa through habitat filtering. Additionally, we observed evidence of niche partitioning within various genera shown by the distinct seasonal patterns of closely related taxa. At broader levels, we did not observe coherent seasonal trends at the class level, with the order and family ranks conditioned to the patterns that exist at the genus level. This study explores the coexistence of niche overlap and niche partitioning in a coastal marine environment.

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