Effect of Container Size on Estimates of Mortality and Predation Rates in Experiments with Macrozooplankton and Larval Fish

1987 ◽  
Vol 44 (9) ◽  
pp. 1534-1543 ◽  
Author(s):  
Yves De Lafontaine ◽  
William C. Leggett
Keyword(s):  
Larval Fish ◽  
Larval Mortality ◽  
Larval Density ◽  
Predation Rate ◽  
Mortality Rates ◽  
Laboratory Studies ◽  
Larval Size ◽  
Capelin Mallotus Villosus ◽  
Order Of Magnitude

We investigated the effect of container size on the predation rate of the jellyfish Aurelia aurita on postemergent capelin (Mallotus villosus) larvae in large in situ cylindrical enclosures. Total depth of the enclosures varied between 1 and 9 m and yielded volumes that ranged from 0.26 to 6.35 m3. Instantaneous mortality rates of capelin larvae due to jellyfish predation varied inversely and nonlinearly with the volume of the enclosure. Over the range of container sizes used, mortality rates differed by one order of magnitude. Container volume explained 80% of the variance in mortality rates, while predator size and larval size accounted for 8.3 and 2.3% of the variability, respectively. Mortality rate was independent of the initial larval density within each container size. Differences in mortality rates among container sizes are explained by the observed differences in the vertical patchiness of larvae among various enclosure sizes. These findings indicate that experiments conducted in small containers typical of those used in laboratory studies seriously overestimate rates of larval mortality due to predation. Direct extrapolation of the results of such laboratory studies to field conditions is therefore not warranted. We conclude that the vertical distributions of predator and prey may be the most important factor controlling predator–prey relationships in situ.

Predation by Jellyfish on Larval Fish: An Experimental Evaluation Employing in situ Enclosures

1988 ◽  
Vol 45 (7) ◽  
pp. 1173-1190 ◽  
Author(s):  
Yves de Lafontaine ◽  
W. C. Leggett
Keyword(s):  
Functional Response ◽  
Larval Fish ◽  
Larval Mortality ◽  
Larval Density ◽  
Larval Survival ◽  
Exogenous Feeding ◽  
Larval Size ◽  
Capelin Mallotus Villosus ◽  
Jellyfish Species

Large in situ enclosures were used to investigate the mortality of yolk-sac larval capelin (Mallotus villosus) by four species of jellyfish predators. Daily instantaneous larval mortality increased linearly with predator density but was independent of initial larval density, indicating a linear functional response of the four jellyfish species. The addition of alternative prey did not modify the linearity of the functional response and did not significantly reduce or increase larval mortality imposed by two jellyfish species. The evidence of a linear response in large enclosures contrasts with the curvilinear (Type II) response previously reported in studies conducted in small laboratory containers. Larval mortality was strongly dependent on predator size within jellyfish species and increased with initial larval size. Larval capelin appeared more susceptible to predation at the time of transition from endogenous to exogenous feeding. Daily larval mortality rates due to predation varied between 0.015 and 1.58 depending on jellyfish species and appeared more strongly determined by body mass than differences in feeding appendages of jellyfish. Our results indicate that reduced larval mortality to jellyfish predation is achievable only by timing larval release in water mass where jellyfish numbers are naturally reduced. We estimated that macro invertebrate predation has the potential of being the primary regulator of larval survival and we hypothesized that large intra- and interannual variation in larval survival may be due to the variability in the emergence timing of capelin larvae relative to the growth trajectory of jellyfish.

Evaluation of in situ Enclosures for Larval Fish Studies

1987 ◽  
Vol 44 (1) ◽  
pp. 54-65 ◽  
Author(s):  
Yves de Lafontaine ◽  
William C. Leggett
Keyword(s):  
Larval Fish ◽  
Fish Larvae ◽  
Low Cost ◽  
Experimental Studies ◽  
Size Composition ◽  
Surrounding Water ◽  
Larval Fishes ◽  
Plastic Bags ◽  
Capelin Mallotus Villosus

Two in situ enclosure designs intended for use in larval fish studies were evaluated for their capability to reproduce and track the physical properties of the surrounding water and to maintain the behavioral characteristics of enclosed organisms. The enclosures, which were constructed of porous material, allowed near instantaneous response to natural variations in temperature, salinity, and dissolved oxygen at all depths. Phytoplankton biomass inside the enclosures was less variable than that observed outside and its size composition was related to the porosity of the material used. Particle sinking rates inside the enclosures were much lower than those previously reported for plastic bags, suggesting a higher degree of turbulence in our enclosures. Newly hatched larval capelin (Mallotus villosus) and Zooplankton stocked into the enclosures exhibited diel migration of amplitude similar to that observed in the field. Zooplankton were more homogeneously distributed than fish larvae although heterogeneity decreased at night for both taxa. Low cost, ease of handling, environmental reproducibility, and quality of replication provided by the enclosures make them particularly appropriate for replicated experimental studies of the interactions between larval fishes, their predators, and prey.

Capture of conspecific planktonic larvae by the suspension-feeding gastropod Crepipatella peruviana: association between adult and larval size

2021 ◽  
Vol 87 (1) ◽  
Author(s):  
G A Rivera-Figueroa ◽  
J A Büchner-Miranda ◽  
L P Salas-Yanquin ◽  
J A Montory ◽  
V M Cubillos ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Larval Mortality ◽  
Feeding Preference ◽  
The Other ◽  
Suspension Feeding ◽  
Adult Size ◽  
Free Living ◽  
Larval Size ◽  
Suspension Feeders ◽  
Planktonic Larvae

ABSTRACT Free-living, planktonic larvae can be vulnerable to capture and ingestion by adult suspension-feeders. This is particularly the case for larvae that settle gregariously in benthic environments where suspension-feeders occur at high densities. Larvae of gregarious suspension-feeding species are at particularly high risk, as adults of their own species often serve as cues for metamorphosis. We conducted laboratory experiments to assess the extent to which adults of the suspension-feeding caenogastropod Crepipatella peruviana would capture and ingest their own larvae. Experiments were conducted with adults of different sizes, with larvae of different ages and sizes, and in the presence or absence of phytoplankton. Adults captured larvae in all experiments. The presence of microalgae in the water did not influence the extent of larval capture. On average, 39% of larvae were captured during the 3-h feeding periods, regardless of adult size. However, up to 34% of the larvae that were captured on the gill were later discarded as pseudofaeces; the other 64% were ingested. The extent of capture by adults was not related to adult size, or to larval size and, thus, to larval age. Our results suggest that the filtration of congeneric larvae by adult C. peruviana is a result of accidental capture rather than a deliberate feeding preference. Such ingestion could, however, still be an important source of larval mortality, especially when the advanced larvae of this species are searching for a suitable substrate for metamorphosis.

scholarly journals Pathogenicity and Infection Cycle of Vibrio owensii in Larviculture of the Ornate Spiny Lobster (Panulirus ornatus)

2012 ◽  
Vol 78 (8) ◽  
pp. 2841-2849 ◽  
Author(s):  
Evan F. Goulden ◽  
Michael R. Hall ◽  
David G. Bourne ◽  
Lily L. Pereg ◽  
Lone Høj
Keyword(s):  
Fluorescent Protein ◽  
Histopathological Examination ◽  
Single Cells ◽  
Larval Mortality ◽  
Spiny Lobster ◽  
Systemic Infection ◽  
Mortality Rates ◽  
Infection Process ◽  
Content Type ◽  
Live Feed

ABSTRACTThe type strain ofVibrio owensii(DY05) was isolated during an epizootic of aquaculture-reared larvae (phyllosomas) of the ornate spiny lobster (Panulirus ornatus).V. owensiiDY05 was formally demonstrated to be the etiological agent of a disease causing rapid and reproducible larval mortality with pathologies similar to those seen during disease epizootics. Vectored challenge via the aquaculture live feed organismArtemia(brine shrimp) caused consistent cumulative mortality rates of 84 to 89% after 72 h, in contrast to variable mortality rates seen after immersion challenge. Histopathological examination of vector-challenged phyllosomas revealed bacterial proliferation in the midgut gland (hepatopancreas) concomitant with epithelial cell necrosis. A fluorescent-protein-labeledV. owensiiDY05 transconjugant showed dispersal of single cells in the foregut and hepatopancreas 6 h postexposure, leading to colonization of the entire hepatopancreas within 18 h and eventually systemic infection.V. owensiiDY05 is a marine enteropathogen highly virulent toP. ornatusphyllosoma that uses vector-mediated transmission and release from host association to a planktonic existence to perpetuate transfer. This understanding of the infection process will improve targeted biocontrol strategies and enhance the prospects of commercially viable larviculture for this valuable spiny lobster species.

scholarly journals Toxicity of Imidacloprid and Diafenthiuron to Chrysoperla Carnea (Stephens) (Neuroptera: Chrysopidae) in the Laboratory Conditions

2009 ◽  
Vol 49 (3) ◽  
pp. 290-296 ◽  
Author(s):  
Gnanadhas Preetha ◽  
Johnson Stanley ◽  
Thiagarajan Chandrasekaran ◽  
Sasthakutty Kuttalam
Keyword(s):  
Plant Protection ◽  
Larval Mortality ◽  
Plant Protection Products ◽  
Threshold Level ◽  
Adult Mortality ◽  
Recommended Dose ◽  
Chrysoperla Carnea ◽  
Laboratory Studies ◽  
Egg Mortality ◽  
Laboratory Conditions

Toxicity of Imidacloprid and Diafenthiuron toChrysoperla Carnea(Stephens) (Neuroptera: Chrysopidae) in the Laboratory ConditionsInsecticides are unavoidable in pest management programs especially when the pest crosses Econimic Threshold Level (ETL). Nevertheless, often the plant protection products kill the natural enemy population making the pest to resurge and thus demanding more sprays. Therefore, insecticides used in IPM programs should be selective enough to spare the beneficials. Laboratory studies were conducted to find out the toxicity of imidacloprid and diafenthiuron to the eggs, larvae and adults ofChrysoperla carnea.Imidacloprid at the recommended dose of 0.28 ml/l caused 15.38% egg mortality, 26.67 and 33.33% larval mortality by ingestion and contact, respectively and 50.00% adult mortality. The egg mortality was about 15.38% and larval mortality of 23.33% and adult mortality of 26.67% was caused by diafenthiuron. Based on the classification given by IOBC/WPRS working group on Pesticides and non-target invertebrates, both the insecticides were classified as harmless toC. carnea, since the recommended dose caused less than 50% mortality in the laboratory conditions.

scholarly journals Tunable In Situ 3D-Printed PVDF-TrFE Piezoelectric Arrays

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5032
Author(s):  
Alec Ikei ◽  
James Wissman ◽  
Kaushik Sampath ◽  
Gregory Yesner ◽  
Syed N. Qadri
Keyword(s):  
3D Printing ◽  
Polyvinylidene Fluoride ◽  
Vinylidene Fluoride ◽  
Mechanical Strain ◽  
Pressure Sensors ◽  
Strain Ratio ◽  
Ex Situ ◽  
Order Of Magnitude ◽  
3D Printed

In the functional 3D-printing field, poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) has been shown to be a more promising choice of material over polyvinylidene fluoride (PVDF), due to its ability to be poled to a high level of piezoelectric performance without a large mechanical strain ratio. In this work, a novel presentation of in situ 3D printing and poling of PVDF-TrFE is shown with a d33 performance of up to 18 pC N−1, more than an order of magnitude larger than previously reported in situ poled polymer piezoelectrics. This finding paves the way forward for pressure sensors with much higher sensitivity and accuracy. In addition, the ability of in situ pole sensors to demonstrate different performance levels is shown in a fully 3D-printed five-element sensor array, accelerating and increasing the design space for complex sensing arrays. The in situ poled sample performance was compared to the performance of samples prepared through an ex situ corona poling process.

scholarly journals Magmatic flare-up causes crustal thickening at the transition from subduction to continental collision

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Carlos E. Ganade ◽  
Pierre Lanari ◽  
Daniela Rubatto ◽  
Joerg Hermann ◽  
Roberto F. Weinberg ◽  
...  
Keyword(s):  
Production Rate ◽  
Continental Margin ◽  
Subduction Zones ◽  
Continental Collision ◽  
Crustal Thickening ◽  
Time Intervals ◽  
West Gondwana ◽  
Continental Arc ◽  
Order Of Magnitude

AbstractAbove subduction zones, magma production rate and crustal generation can increase by an order of magnitude during narrow time intervals known as magmatic flare-ups. However, the consequences of these events in the deep arc environment remain poorly understood. Here we use petrological and in-situ zircon dating techniques to investigate the root of a continental arc within the collisional West Gondwana Orogen that is now exposed in the Kabyé Massif, Togo. We show that gabbros intruded 670 million years ago at 20–25 km depth were transformed to eclogites by 620 million years ago at 65–70 km depth. This was coeval with extensive magmatism at 20–40 km depth, indicative of a flare-up event which peaked just prior to the subduction of the continental margin. We propose that increased H2O flux from subduction of serpentinized mantle in the hyper-extended margin of the approaching continent was responsible for the increased magma productivity and crustal thickening.

Estimation and Scaling of the Near-Saturated Hydraulic Conductivity

1999 ◽  
Vol 30 (3) ◽  
pp. 177-190 ◽  
Author(s):  
Per Atle Olsen
Keyword(s):  
Hydraulic Conductivity ◽  
Saturated Hydraulic Conductivity ◽  
Scaling Analysis ◽  
Laboratory Measurements ◽  
Estimation Errors ◽  
Geometric Means ◽  
Top Soil ◽  
Structured Soils ◽  
Order Of Magnitude

The hydraulic conductivity in structured soils is known to increase drastically when approaching saturation. Tension infiltration allows in situ infiltration of water at predetermined matric potentials, thus allowing exploration of the hydraulic properties near saturation. In this study, the near saturated (ψ≥-0.15 m) hydraulic conductivity was estimated both in the top- and sub-soil of three Norwegian soils. A priory analysis of estimation errors due to measurement uncertainties was conducted. In order to facilitate the comparison between soils and depths, scaling analysis was applied. It was found that the increase in hydraulic conductivity with increasing matric potentials (increasing water content) was steeper in the sub-soil than in the top-soil. The estimated field saturated hydraulic conductivity was compared with laboratory measurements of the saturated hydraulic conductivity. The geometric means of the laboratory measurements was in the same order of magnitude as the field estimates. The variability of the field estimates of the hydraulic conductivity from one of the soils was also assessed. The variability of the field estimates was generally smaller than the laboratory measurements of the saturated hydraulic conductivity.

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