A technique for detection of larval fish in the digestive tract of predators by otolith marking

2017 ◽  
Vol 68 (1) ◽  
pp. 167 ◽  
Author(s):  
M. I. Gómez ◽  
C. M. Fuentes
Keyword(s):  
Digestive Tract ◽  
Larval Fish ◽  
Fish Larvae ◽  
Larval Mortality ◽  
Experimental Studies ◽  
Alizarin Red ◽  
Prochilodus Lineatus ◽  
Predator Prey ◽  
Fish Predators

The aim of the present study was to develop a method to unequivocally detect pre-flexion fish larvae in the digestive tracts of fish predators, even several hours after their ingestion. For this purpose, we evaluated larval mortality and the quality of the marks generated in sagitta otoliths after 0.5- or 2-h immersion in 50–800mg L–1 alizarin red S stain. The optimal condition (2h, 200mg L–1) was chosen to stain Prochilodus lineatus larvae, which were offered to single predators at 5 or 12 days after marking (DAM). The otoliths were searched in the digestive tract of predators killed 1–17h after ingestion of the prey, and were then examined for mark presence. Otolith recovery rates were high (>70%) and mark detection was above 80% up to 3h after ingestion, but even after 9h, 20–40% of the otoliths were recovered, with mark detection levels of 65%. A higher number of DAM was associated with a higher success in otolith recovery and mark detection. Otolith marking constitutes a single and inexpensive technique that could be applied in both laboratory and field experimental studies of predator–prey interactions.

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.

scholarly journals Suction Flows Generated by the Carnivorous Bladderwort Utricularia—Comparing Experiments with Mechanical and Mathematical Models

Fluids ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 33 ◽  
Author(s):  
Krizma Singh ◽  
Roberto C. Reyes ◽  
Gabriel Campa ◽  
Matthew D. Brown ◽  
Fatima Hidalgo ◽  
...  
Keyword(s):  
Solid Mechanics ◽  
Larval Fish ◽  
Fish Larvae ◽  
Experimental Studies ◽  
Axial Flow ◽  
Aquatic Organisms ◽  
Suction Feeding ◽  
Scaled Model ◽  
Feeding Mode ◽  
Biological Studies

Suction feeding is a well-understood feeding mode among macroscopic aquatic organisms. The little we know about small suction feeders from larval fish suggests that small suction feeders are not effective. Yet bladderworts, an aquatic carnivorous plant with microscopic underwater traps, have strong suction performances despite having the same mouth size as that of fish larvae. Previous experimental studies of bladderwort suction feeding have focused on the solid mechanics of the trap door’s opening mechanism rather than the mechanics of fluid flow. As flows are difficult to study in small suction feeders due to their small size and brief event durations, we combine flow visualization on bladderwort traps with measurements on a mechanical, dynamically scaled model of a suction feeder. We find that bladderwort traps generate flows that are more similar to the inertia-dominated flows of adult fish than the viscosity-dominated flows of larval fish. Our data further suggest that axial flow transects through suction flow fields, often used in biological studies to characterize suction flows, are less diagnostic of the relative contribution of inertia versus viscosity than transverse transects.

scholarly journals Enhancement of Live Food Nutritional Status with Essential Nutrients for Improving Aquatic Animal Health: A Review

Animals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2457
Author(s):  
Nur Amalina Samat ◽  
Fatimah Md Yusoff ◽  
Nadiah W. Rasdi ◽  
Murni Karim
Keyword(s):  
Nutritional Quality ◽  
Larval Fish ◽  
Fish Larvae ◽  
Animal Health ◽  
Live Food ◽  
Aquatic Animal ◽  
Culture Techniques ◽  
Dietary Requirements ◽  
Macro Nutrients

At the present time, no artificial larval diet is capable of entirely fulfilling the dietary requirements of several larval fish and crustacean species. Zooplankton live food is the basic foundation of fish larviculture, and successful rearing of fish larvae still heavily depends on an adequate supply of nutritious live food. Despite being important, the production protocols of copepods and cladocerans (Moina) are still underdeveloped in hatcheries. Rotifers and Artemia are the most commonly used live foods. However, these live foods are evidently lacking in crucial nutrient constituents. Hence, through nutrient enrichment, live food with the nutritional profile that meets the requirements of fish larvae can be produced. With the aim to maximize the effectiveness of production to optimize profitability, it is important to evaluate and improve culture techniques for the delivery of micro- and macro-nutrients as feed supplements to larvae in aquaculture systems. Bioencapsulation and enrichment are the evolving techniques in aquaculture that are commonly employed to enhance the nutritional quality of live food by integrating nutrients into them, which subsequently improves the growth, survival, and disease resistance of the consuming hosts. This review aims to highlight some of the approaches and methods used to improve the nutritional quality of live food by modifying their nutrient composition, which could have immense promise in the enhancement of aquatic animal health.

scholarly journals The Survival of Larval Fish in the Northern North sea According to the Quality of the sea Water

1961 ◽  
Vol 41 (2) ◽  
pp. 305-312 ◽  
Author(s):  
J. H. Fraser
Keyword(s):  
North Sea ◽  
Food Supply ◽  
Sea Water ◽  
Larval Fish ◽  
Fish Larvae ◽  
English Channel ◽  
Fish Eggs ◽  
Northern North Sea ◽  
Possible Cause

The numbers of fish eggs and planktonic stages of fish taken during a 5-year period by the Scottish research vessels in the northern North Sea have been associated with the presence of Sagitta elegans and S. setosa in the same collections and over an 11-year period with the presence or absence of S. elegans. The results confirm Russell's findings in the English Channel that fish larvae are more abundant when S. elegans is present than when S. setosa is present.The total numbers of fish eggs do not show these differences; spawning does not appear to be any more productive in water associated with S. elegans, rather the reverse, and this is shown to be so for the eggs of those species separately examined. Numbers of the larvae were distinctly greater in the ‘mixed’ conditions indicated by the presence of S. elegans and a more abundant food supply is a possible cause. That the differences may signify a more fundamental effect, however, is suggested by the figures for cod and haddock eggs, which show the earliest stages to be more abundant where S. elegans was absent although later stages were more abundant when S. elegans was present.

Pengaruh ovaprim, aromatase inhibitor, dan hipofisa terhadap kualitas telur ikan Lele Dumbo (Clarias gariepinus)

2017 ◽  
Vol 5 (1) ◽  
Author(s):  
Erwin A. Aziz ◽  
Ockstan Kalesaran
Keyword(s):  
Survival Rate ◽  
Experimental Design ◽  
Aromatase Inhibitor ◽  
Fish Larvae ◽  
Clarias Gariepinus ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
The Difference ◽  
Hatching Eggs

This study aimed to determine the effect of ovaprim hormone, aromatase inhibitor and pituitary on the quality of the catfish eggs (Clarias gariepinus). Experimental Design used was Completely Randomized Design (CRD) with four treatments, each with three replications. Treatment A: ovaprim; treatment B: Aromatase inhibitors, treatment C: hypophysis and treatment D: Control. The results showed that the difference in treatment gave highly significant effect on fertilization and hatching eggs but no significant effect on the survival rate of larvae. Aromatase inhibitor hormone was the best because it provided highly significant effect on fertilization (92.66%), hatchability of eggs (95%), and surviva rate (81.33%) of fish larvae.   Keywords : Clarias gariepinus. Ovaprim, Aromatase Inhibitor, Hypophysis, egg, larvae

The system of indicators of the quality of the carbon-carbon composite materials and technologies of their production

2018 ◽  
pp. 127-132
Author(s):  
T. N. Antipova ◽  
D. S. Shiroyan
Keyword(s):  
Composite Material ◽  
Low Cost ◽  
Experimental Studies ◽  
Carbon Matrix ◽  
Carbon Composite ◽  
Optimal Number ◽  
Laboratory Equipment ◽  
Carbon Composite Material ◽  
Carbon Composite Materials

The system of indicators of quality of carbon-carbon composite material and technological operations of its production is proved in the work. As a result of the experimental studies, with respect to the existing laboratory equipment, the optimal number of cycles of saturation of the reinforcing frame with a carbon matrix is determined. It was found that to obtain a carbon-carbon composite material with a low cost and the required quality indicators, it is necessary to introduce additional parameters of the pitch melt at the impregnation stage.

scholarly journals Do we have enough information to apply the ecosystem approach to management of deep-sea fisheries? An example from the West of Scotland

2010 ◽  
Vol 68 (2) ◽  
pp. 265-280 ◽  
Author(s):  
Johanna J. Heymans ◽  
Kerry L. Howell ◽  
Morag Ayers ◽  
Michael T. Burrows ◽  
John D. M. Gordon ◽  
...  
Keyword(s):  
Deep Sea ◽  
Ecosystem Model ◽  
Ecosystem Approach ◽  
The West ◽  
Holistic View ◽  
Predator Prey ◽  
Relative Paucity ◽  
Water Ecosystem ◽  
Fisheries Interactions

Abstract Heymans, J. J., Howell, K. L., Ayers, M., Burrows, M. T., Gordon, J. D. M., Jones, E. G., and Neat, F. 2011. Do we have enough information to apply the ecosystem approach to management of deep-sea fisheries? An example from the West of Scotland. – ICES Journal of Marine Science, 68: 265–280. There is currently a global call for more use of an ecosystem approach to fisheries management (EAFM), and ecosystem models such as Ecopath with Ecosim (EwE) are being used to provide a holistic view of ecosystem–fisheries interactions. Although these can be useful for an EAFM, the relative paucity of data available for deep-sea ecosystems raises concerns whether we can effectively apply an EAFM to the deep sea. The deep-sea ecosystem off the west coast of Scotland has been studied for longer and in more detail than most. This study assimilates the significant published and unpublished information available on this ecosystem into an EwE model. The results suggest that there are sufficient data available to construct an ecosystem model, but the quality of the data varies and serious potential sources of error are present in biomass and discard estimates. The assumptions needed to produce a model are varied and must be considered when interpreting the outputs of the model. Ecosystem modelling provides a unique view of the deep-water ecosystem and facilitates hypothesis development concerning predator–prey and inter-fishery interactions. Sharks are used to illustrate the benefits of using an ecosystem model to describe changes in their biomass and their prey species. The results show that both fishing for sharks and fishing for their prey affect the biomass of sharks.

scholarly journals Fish larvae exploit edge vortices along their dorsal and ventral fin folds to propel themselves

2016 ◽  
Vol 13 (116) ◽  
pp. 20160068 ◽  
Author(s):  
Gen Li ◽  
Ulrike K. Müller ◽  
Johan L. van Leeuwen ◽  
Hao Liu
Keyword(s):  
Larval Fish ◽  
Fish Larvae ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Bony Fish ◽  
The Body ◽  
Functional Explanation ◽  
Image Velocimetry ◽  
Median Fins

Larvae of bony fish swim in the intermediate Reynolds number ( Re ) regime, using body- and caudal-fin undulation to propel themselves. They share a median fin fold that transforms into separate median fins as they grow into juveniles. The fin fold was suggested to be an adaption for locomotion in the intermediate Reynolds regime, but its fluid-dynamic role is still enigmatic. Using three-dimensional fluid-dynamic computations, we quantified the swimming trajectory from body-shape changes during cyclic swimming of larval fish. We predicted unsteady vortices around the upper and lower edges of the fin fold, and identified similar vortices around real larvae with particle image velocimetry. We show that thrust contributions on the body peak adjacent to the upper and lower edges of the fin fold where large left–right pressure differences occur in concert with the periodical generation and shedding of edge vortices. The fin fold enhances effective flow separation and drag-based thrust. Along the body, net thrust is generated in multiple zones posterior to the centre of mass. Counterfactual simulations exploring the effect of having a fin fold across a range of Reynolds numbers show that the fin fold helps larvae achieve high swimming speeds, yet requires high power. We conclude that propulsion in larval fish partly relies on unsteady high-intensity vortices along the upper and lower edges of the fin fold, providing a functional explanation for the omnipresence of the fin fold in bony-fish larvae.

scholarly journals Automation of skeletal staining in the evaluation of teratogenicity

1969 ◽  
Vol 3 (2) ◽  
pp. 197-205 ◽  
Author(s):  
A. D. Randle
Keyword(s):  
Alizarin Red S ◽  
Alizarin Red

A number of variables affecting the quality of foetal mouse preparations stained with alizarin red S have been investigated. A seven-day 'Histokinette' procedure has been developed to macerate and stain foetal mice by a modification of Dawson's method.

scholarly journals A faster escape does not enhance survival in zebrafish larvae

2017 ◽  
Vol 284 (1852) ◽  
pp. 20170359 ◽  
Author(s):  
Arjun Nair ◽  
Christy Nguyen ◽  
Matthew J. McHenry
Keyword(s):  
High Speed ◽  
Larval Fish ◽  
Body Position ◽  
Three Dimensional ◽  
Limited Range ◽  
The Body ◽  
Model Parameters ◽  
Fish Prey ◽  
Zebrafish Larvae ◽  
Fish Predators

An escape response is a rapid manoeuvre used by prey to evade predators. Performing this manoeuvre at greater speed, in a favourable direction, or from a longer distance have been hypothesized to enhance the survival of prey, but these ideas are difficult to test experimentally. We examined how prey survival depends on escape kinematics through a novel combination of experimentation and mathematical modelling. This approach focused on zebrafish ( Danio rerio ) larvae under predation by adults and juveniles of the same species. High-speed three-dimensional kinematics were used to track the body position of prey and predator and to determine the probability of behavioural actions by both fish. These measurements provided the basis for an agent-based probabilistic model that simulated the trajectories of the animals. Predictions of survivorship by this model were found by Monte Carlo simulations to agree with our observations and we examined how these predictions varied by changing individual model parameters. Contrary to expectation, we found that survival may not be improved by increasing the speed or altering the direction of the escape. Rather, zebrafish larvae operate with sufficiently high locomotor performance due to the relatively slow approach and limited range of suction feeding by fish predators. We did find that survival was enhanced when prey responded from a greater distance. This is an ability that depends on the capacity of the visual and lateral line systems to detect a looming threat. Therefore, performance in sensing, and not locomotion, is decisive for improving the survival of larval fish prey. These results offer a framework for understanding the evolution of predator–prey strategy that may inform prey survival in a broad diversity of animals.

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