A Study of Diffusional Permeability of Water, Sodium and Chloride in Yolk-Sac Larvae of Cod (Gadus Morhua L.)

1989 ◽  
Vol 147 (1) ◽  
pp. 125-132 ◽  
Author(s):  
PETER TYTLER ◽  
MICHAEL V. BELL
Keyword(s):  
Gadus Morhua ◽  
Sea Water ◽  
Fish Larvae ◽  
Yolk Sac ◽  
Adult Fish ◽  
Permeability Coefficients ◽  
Osmotic Permeability ◽  
Marine Fish Larvae ◽  
Diffusional Permeability ◽  
Previous Hypothesis

1. The fluxes of 3H2O, 22Na and 36Cl were simultaneously measured in yolk-sac larvae of cod (Gadus morhua L.) in 34‰ sea water at 4.5°C. 2. The rates of turnover of all three isotopes were higher than in adult fish. Diffusional permeability coefficients, which relate ion fluxes to surface area, were however lower, indicating that larvae are less permeable than adults. Furthermore, there is close agreement between the diffusional and osmotic permeability coefficients, which supports a previous hypothesis that relatively low drinking rates in marine fish larvae are a consequence of low integumental permeability. 3. Estimates of the sodium and chloride concentrations derived from the equilibrium levels of 22Na, 36Cl and 3H2O indicate that yolk-sac larvae of cod regulate their body fluids hypotonic to sea water. Also, the ionic concentrations of the tissues of yolk-sac cod larvae are similar to those of adults.

The Effects of External Salinity on the Drinking Rates of the Larvae of Herring, Plaice and Cod

1988 ◽  
Vol 138 (1) ◽  
pp. 1-15 ◽  
Author(s):  
P. TYTLER ◽  
J. H. BLAXTER
Keyword(s):  
Time Course ◽  
Gadus Morhua ◽  
Sea Water ◽  
Fluorescein Isothiocyanate ◽  
Yolk Sac ◽  
Clupea Harengus ◽  
Larval Stages ◽  
First Feeding ◽  
Fluorescein Isothiocyanate Dextran ◽  
External Salinity

Drinking responses to salinity change in the larvae of herring (Clupea harengus L.), plaice (Pleuronectes platessa L.) and cod (Gadus morhua L.) were measured from the time course of uptake of dextran labelled with tritium, following immersion in solutions of 32‰ and 16‰ sea water. The yolk sac and first feeding larval stages of all three species drink in both salinities. Furthermore, post-yolk sac stages appear to adjust their drinking rates to compensate for different salinities in a manner similar to that of the adults. Drinking rates in 32‰ sea water are approximately double those in 16‰. Mass-related drinking rates of larvae are higher than those in adults, but the differences do not match the differences in surface area to mass ratios, suggesting that larval skin is less permeable to water than is adult gill epithelium. Water absorption is indicated by the evidence of concentration of dextran in the gut. The estimates of drinking rates from tritiated dextran uptake are supported by epifluorescence microscopical measurements of the uptake of fluorescein isothiocyanate dextran.

Temperature-Dependence of Permeability to Water and to Sodium of the Gill Epithelium of the Eel Anguilla Anguilla

1972 ◽  
Vol 56 (3) ◽  
pp. 587-600 ◽  
Author(s):  
R. MOTAIS ◽  
J. ISAIA
Keyword(s):  
Temperature Dependence ◽  
Water Permeability ◽  
Sea Water ◽  
Anguilla Anguilla ◽  
Temperature Acclimation ◽  
Osmotic Gradient ◽  
Surprising Result ◽  
Sodium Permeability ◽  
Osmotic Permeability ◽  
Diffusional Permeability

1. The temperature dependence of diffusional permeability to water was studied in freshwater-adapted and seawater-adapted eels. The pattern of temperature acclimation is discussed. 2. The ratio of water permeability to sodium permeability is approximately 3 at 25°C, but falls to 1 at 5°C. This drop is mainly due to a diminution of the water permeability, the temperature coefficients being much higher for water than for sodium. 3. The relatively independent variations of water and sodium permeabilities in the seawater-adapted fish probably indicate a certain dissociation between water movements and salt movements. 4. In the freshwater-adapted eel the osmotic permeability is considerably higher than the diffusional permeability, which supports the previously advanced hypothesis concerning the presence of water-filled channels in the branchial epithelium. 5. In the seawater-adapted eel the osmotic permeability is lower than the diffusional permeability, this difference being greater the lower the temperature. This surprising result must signify either that the osmotic pressure difference between blood and sea water does not represent the true osmotic gradient across the membrane, or that a reabsorption of water linked with a movement of solutes occurs in a specialized region of the gill.

Size-dependent foraging of larval Atlantic cod (Gadus morhua)

2004 ◽  
Vol 82 (8) ◽  
pp. 1380-1389 ◽  
Author(s):  
Velmurugu Puvanendran ◽  
Karine Salies ◽  
Benjamin Laurel ◽  
Joseph A Brown
Keyword(s):  
Marine Fish ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Prey Selection ◽  
Fish Larvae ◽  
Growth And Survival ◽  
Size Dependent ◽  
Marine Fish Larvae ◽  
Key Factor ◽  
Foraging Environment

Most marine fish larvae are thought to be gape-limited predators, and the presence of suitably sized prey at the appropriate time in the foraging environment is a key factor for their growth and survival. Two experiments were carried out: in experiment 1, we investigated feeding of Atlantic cod (Gadus morhua L., 1758) larvae from 5 to 35 days post hatch on prey of three different sizes: two different-sized strains of rotifers, small rotifers (SR) and large rotifers (LR), and Artemia Leach, 1819 nauplii (AN), or an equal mixture of the three types of prey (MIX). In experiment 2, cod larvae were fed SR, LR, or a combination of SR and LR (MIX-R) at concentrations of 1500 and 4000 prey·L–1 from 4 to 20 days post hatch. Feeding incidence, number of prey in the gut, mouth gape, and prey selection were measured. In experiment 1, feeding incidence was initially higher in the SR treatment, while larvae failed to start feeding in either the LR or the AN treatment at 5 dph. Larvae in the LR treatment started feeding at 8 dph, and feeding incidence was comparable to that in the SR treatment, but the total number of prey eaten was higher in the SR than in the LR treatment until 20 dph. Larvae did not start feeding on AN until 26 dph, although they attacked them from 5 dph. In the MIX-R treatment in experiment 2, larvae fed selectively on LR at 4000 prey·L–1, whereas no selection was observed at 1500 prey·L–1. Our results suggest that cod larvae are gape-limited predators and the concentration of prey affects prey selection.

Changes in Behaviour at Onset of Exogenous Feeding in Marine Fish Larvae

1992 ◽  
Vol 49 (8) ◽  
pp. 1570-1572 ◽  
Author(s):  
Anne Berit Skiftesvik
Keyword(s):  
Marine Fish ◽  
Swimming Speed ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Fish Larvae ◽  
Scophthalmus Maximus ◽  
Exogenous Feeding ◽  
First Feeding ◽  
Marine Fish Larvae ◽  
Turbot Scophthalmus Maximus

The activity and swimming speed of fed and starved larvae of Atlantic cod (Gadus morhua) and turbot (Scophthalmus maximus) were measured from hatching to metamorphosis. The results indicate changes in behaviour over time, as well as differences between starved and fed larvae. It is suggested that determining the point at which activity increases and swimming speed during active periods decreases may be relevant as an indicator of the time of first feeding in marine fish larvae.

Isolation, morphometry, and culture of Colurella sp. (Rotifera: Ploimida)

2013 ◽  
Vol 1 (2) ◽  
pp. 143
Author(s):  
Petrus P Letsoin ◽  
Henneke Pangkey ◽  
Julius Sampekalo ◽  
Inneke F.M Rumengan ◽  
Stenly Wullur ◽  
...  
Keyword(s):  
Body Size ◽  
Marine Fish ◽  
Fish Larvae ◽  
Nannochloropsis Oculata ◽  
Tropical Fish ◽  
Sampling Location ◽  
Larval Rearing ◽  
Brachionus Rotundiformis ◽  
Marine Fish Larvae ◽  
Significant Difference

The rotifer Brachionus rotundiformis (total body length 240.59±10.24 μm, lorica length 175.28±9.18 μm, and lorica width 124.28±7.76μm) is commonly used as starter food in the larval rearing of marine fish. But, larvae of some marine tropical fish species required starter food with body size smaller than B. rotundiformis. The present study was aimed to isolate minute rotifers from nature and to assess the possibility of culturing these rotifers. Sampling of rotifers was conducted in an estuary of Mangket (Kema-Minut), using plankton net (mesh size 40 µm). A trial of culturing the rotifers was conducted at salinities of 10, 20 and 30 ppt by using a microalga, Nannochloropsis oculata. A species of rotifer identified as Colurella sp. (family Lepadellidae) was successfully isolated from the sampling location. Body size of Colurella sp. was extremely small (Total length 123.22±5.45 μm, lorica length 95.96±3.81 μm, and lorica width 53.57±3.11 μm), which were smaller than Brachionus rotundiformis SS-type as a conventional starter food for marine fish larvae.  Results of culturing the minute rotifer Colurella sp. showed that the species grew well at salinities of 10, 20 and 30 ppt with no significant difference among treatments (ANOVA, p>0.05), indicating a potential use of minute rotifer Colurellasp. as starter food for marine fish larvae. Rotifera Branchionus rotundiformis (ukuran tubuh: panjang total 240,59±10,24 μm, panjang lorika 175,28±9,18 μm, dan lebar lorika 124,28±7,76μm) sering digunakan sebagai pakan awal pemeliharaan larva ikan laut. Namun, larva beberapa spesis ikan laut tropis membutuhkan pakan awal berukuran tubuh lebih kecil dari Branchionus rotundiformis. Penelitian ini bertujuan untuk mendapatkan minute rotifer dari alam (berukuran tubuh lebih kecil dari B. rotundiformis) dan menguji kemungkinan pemeliharaannya. Sampling rotifer dilakukan di perairan estuari Desa Mangket (Kema-Minut), menggunakan plankton net (ukuran mata jaring 40 µm). Uji coba pemeliharaan dilakukan pada salinitas (10, 20, dan 30 ppt) dengan menggunakan Nannochloropsis oculata. Satu spesies minute rotifer yang teridentifikasi sebagai Colurella sp. (family Lepadellidae) berhasil diisolasi dari lokasi sampling. Colurella sp. memiliki ukuran tubuh sangat kecil (panjang total [PT] 123,22±5,45 µm, panjang lorika [PL] 95,96±3,81 µm, dan lebar lorik [LL] 53,57±3,11 µm) yang mana lebih kecil dari Branchionus rotundiformis tipe-SS sebagai pakan awal larva ikan laut. Hasil uji coba pemeliharaan minute rotifer Colurella sp. menunjukkan bahwa spesis ini dapat tumbuh pada salinitas 10, 20, dan 30 ppt dengan perbedaan kepadatan populasi yang tidak signifikan antar perlakuan (Uji ANOVA, p > 0.05) mengindikasikan potensi pemanfaatan minute rotifer Colurella sp. sebagai pakan awal larva ikan laut.

scholarly journals A Preliminary Survey on the Planktonic Biota in a Hypersaline Pond of Messolonghi Saltworks (W. Greece)

Diversity ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 270
Author(s):  
George N. Hotos
Keyword(s):  
New Species ◽  
Marine Fish ◽  
Broad Spectrum ◽  
Fish Larvae ◽  
Live Food ◽  
Preliminary Survey ◽  
Genus Level ◽  
Marine Fish Larvae ◽  
Alternaria Sp ◽  
Different Strains

During a survey in 2015, an impressive assemblage of organisms was found in a hypersaline pond of the Messolonghi saltworks. The salinity ranged between 50 and 180 ppt, and the organisms that were found fell into the categories of Cyanobacteria (17 species), Chlorophytes (4 species), Diatoms (23 species), Dinoflagellates (1 species), Protozoa (40 species), Rotifers (8 species), Copepods (1 species), Artemia sp., one nematode and Alternaria sp. (Fungi). Fabrea salina was the most prominent protist among all samples and salinities. This ciliate has the potential to be a live food candidate for marine fish larvae. Asteromonas gracilis proved to be a sturdy microalga, performing well in a broad spectrum of culture salinities. Most of the specimens were identified to the genus level only. Based on their morphology, as there are no relevant records in Greece, there is a possibility for some to be either new species or strikingly different strains of certain species recorded elsewhere.

Net Fluxes of Water in the Isolated Gills of Anguilla Dieffenbachii

1974 ◽  
Vol 60 (3) ◽  
pp. 769-781
Author(s):  
T. J. SHUTTLEWORTH ◽  
R. F. H. FREEMAN
Keyword(s):  
Sea Water ◽  
Water Flux ◽  
Freshwater Teleost ◽  
Osmotic Permeability ◽  
Direct Measurements ◽  
Net Flux ◽  
Anguilla Dieffenbachii ◽  
Net Fluxes ◽  
Freshwater Eels ◽  
Net Water Flux

1. Measurements of net flux of water have been made on isolated gills removed from freshwater-adapted and seawater-adapted eels and incubated in various media of differing osmotic pressure. 2. From these measurements it has been possible to determine the osmotic permeability coefficient of the gill directly from the net water flux. The values obtained (0.50±0.14x10-5 cm.sec-1 for freshwater eels and 0.43±0.07x10-5 cm.sec-1 for seawater-adapted eels) indicate that there was no significant change in this parameter on adaptation of the eels to sea water. 3. The direct measurements made of the net water flux across the isolated gills appear to be compatible with the osmoregulatory pattern of eels as deduced by other workers using different techniques. In particular they illustrate and further emphasize the significance of drinking in the freshwater fish. 4. Calculations indicate that, for a freshwater teleost, the osmotic and ionic problems caused by drinking in fresh water have an insignificant energetic effect and hence, energetically, it matters little to the fish whether it drinks or not.

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