11,522 research outputs found
Impact of sheep grazing on juvenile sea bass, Dicentrarchus labrax L., in tidal salt marshes
No full textThe diet of young of the year sea bass, Dicentrarchus labrax L., from sheep grazed and ungrazed tidal salt marshes were com-pared qualitatively and quantitatively in Mont Saint-Michel Bay. In areas without grazing pressure, the vegetation gradient changes from a pioneer Puccinellia maritima dominated community at the tidal ¯at boundaries through a Atriplex portulacoides dominated community in the middle of the marsh to a mature Elymus pungens dominated community at the landward edge. The A. portula-coides community is highly productive and provides important quantities of litter which provides a habitat and good supply to substain high densities of the detrivorous amphipod Orchestia gammarellus. In the grazed areas, the vegetation is replaced by P. maritima communities, a low productive grass plant, and food availability and habitat suitability are reduced for O. gammarellus. Juvenile sea bass colonise the salt marsh at ¯ood during 43% of the spring tides which inundate the salt marsh creeks. They forage inside the marsh and feed mainly on O. gammarellus in the ungrazed marshes. In grazed areas, this amphipod is replaced by other species and juvenile sea bass consume less food from the marsh. This illustrates a direct effect of a terrestrial herbivore on a coastal food web, and suggests that management of salt marsh is complex and promotion of one component of their biota could involve reductions in other species
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Master's Thesis Recital (double bass)
No full texttextSuite no.5 in C minor for violoncello solo / Johann Sebastian Bach -- Treizieme concert a 2 instruments a l'unisson / Francois Couperin -- Concerto for couble bass in b minor / Giovanni Bottesini -- Bass trip / Peteris Vasks.Musi
Cellular alterations in different organs of European sea bass Dicentrarchus labrax (L.) exposed to cadmium
No full textSpecimens of farmed European sea bass (Dicentrarchus labrax L., 1758) were exposed to different cadmium (Cd) concentrations (4.47, 5.63, 7.08 and 8.91 mg l(-1)) for 24 and 48 h. The effects of Cd on numbers of some cell types and structures (i.e., chloride cells, CCs; macrophage aggregates, MAs; rodlet cells, RCs) and on structure and ultrastructure of the main organs (gill, liver, intestine, kidney) were studied with routine process for light and transmission electron microscopy. Following cadmium exposure, the numbers of branchial CCs as well as intestinal and renal RCs increased significantly within 24h. Increase in metal concentration did not affect the magnitude of the numerical increment of the aforementioned cells. Moreover, in treated fish (24 and 48 h) the numbers of MAs in both head kidney and spleen were significantly higher than in control conspecifics, whilst the global area of MAs was less influenced by the acute treatment. In exposed sea bass, all the examined organs exhibited cellular modifications which appeared time- and dose-dependent. The gills showed telangectasia, lamellar fusion, oedema, epithelial lifting and leukocyte infiltration. In the liver, kidney and intestine acute cell swelling and vacuolization were common. Ultrastructurally the alterations observed frequently in hepatocytes, tubular epithelial cells and enterocytes included presence of numerous myelinoid bodies, damaged mitochondria, dilatation of endoplasmic reticulum, high number of lysosomes and autophagolysosomes. In intestinal and kidney tubular epithelia of treated fish, rodlet cells displayed some anomalies like dilatation of nuclear envelope, cytoplasmic vacuolization, presence of myelinoid bodies, rodlets degeneration and extensive discharge activity.[...
Letter from L. B. Williams to Carl Hayden
No full textLetter from L. B. Williams to Carl Hayden regarding W. W. Bass' resistance to the park bill
Spontaneous haemolytic activity of Atlantic halibut (Hippoglossus hippoglossus L.) and sea bass (Dicentrarchus labrax) serum
No full textThe spontaneous haemolytic (SH) activity of sera was compared in groups of cultured halibut and sea bass. The optimum assay temperature was determined for each species and different red blood cell donors were tested. The effects of heat inactivation, storage temperature and of different agents like EDTA, EGTA, yeast cell components and bacterial LPS were compared. Halibut sera gave optimum lysis with sheep red blood cells (RBC) at 16 °C whereas sea bass sera showed optimum lysis with rabbit RBC at 37 °C. The haemolytic activity of halibut sera was inactivated at 45 °C while sea bass sera were inactivated at 56 °C. The haemolytic activity of halibut sera was significantly reduced during short-term storage at −80 °C, whereas the sea bass sera maintained fairly good activity after 1-year storage at −80 °C. EGTA and EDTA inhibited the spontaneous haemolytic activity of sera from both the species. Zymosan and MacroGard from yeast cells also inhibited the haemolytic activity of the sera of both species, whereas LPS had a very slight effect. Considerable variation in haemolytic activity was observed within both the halibut and sea bass groups studied
Cellular alterations in different organs of European sea bass Dicentrarchus labrax (L.) exposed to cadmium.
No full textSpecimens of farmed European sea bass (Dicentrarchus labrax L., 1758) were exposed to different cadmium (Cd) concentrations (4.47, 5.63, 7.08 and 8.91 mg l-1) for 24 and 48 hours.
The effects of Cd on numbers of some cell types and structures (i.e. chloride cells, CCs; macrophage aggregates, MAs; rodlet cells, RCs) and on structure and ultrastructure of the main organs (gill, liver, intestine, kidney) were studied with routine process for light and transmission electron microscopy.
Following cadmium exposure, the numbers of branchial CCs as well as intestinal and renal RCs increased significantly within 24 h. Increase in metal concentration did not affect the magnitude of the numerical increment of the aforementioned cells. Moreover, in treated fish (24 and 48 h) the numbers of MAs in both head kidney and spleen were significantly higher than in control conspecifics, whilst the global area of MAs was less influenced by the acute treatment.
In exposed sea bass, all the examined organs exhibited cellular modifications which appeared time- and dose-dependent. The gills showed telangectasia, lamellar fusion, oedema, epithelial lifting and leukocyte infiltration. In the liver, kidney and intestine acute cell swelling and vacuolization were common. Ultrastructurally the alterations observed frequently in hepatocytes, tubular epithelial cells and enterocytes included presence of numerous myelinoid bodies, damaged mitochondria, dilatation of endoplasmic reticulum, high number of lysosomes and autophagolysosomes. In intestinal and kidney tubular epithelia of treated fish, rodlet cells displayed some anomalies like dilatation of nuclear envelope, cytoplasmic vacuolization, presence of myelinoid bodies, rodlets degeneration and extensive discharge activity
Feeding ecology of 0-group sea bass Dicentrarchus labrax in salt marshes of Mont Saint-Michel bay (France)
No full text0-group sea bass, Dicentrarchus labrax, colonize intertidal marsh creeks of Mont Saint Michel Bay, France, on spring tides (e.g., 43% of the tides) during flood and return to coastal waters during ebb. Most arrived with empty stomachs (33%), and feed actively during their short stay in the creeks (from 1 to 2 h) where they consumed on average a minimum of 8% of their body weight. During flood tide, diet was dominated by mysids, Neomysis integer, which feed on marsh detritus. During ebb, when young sea bass left tidal marsh creeks, the majority had full stomachs (more than 98%) and diet was dominated by the most abundant marsh (including vegetated tidal flats and associated marsh creeks) resident amphipod, Orchestia gammarellus. Temporal and tidal effects on diet composition were shown to be insignificant. Foraging in vegetated flats occurs very rarely since they are only flooded by about 5% of the tides. It was shown that primary and secondary production of intertidal salt marshes play a fundamental role in the feeding of 0-group sea bass. This suggests that the well known nursery function of estuarine systems, which is usually restricted to subtidal and intertidal flats, ought to be extended to the supratidal, vegetated marshes and mainly to intertidal marsh creeks
PREFERENCES OF MID-ATLANTIC SEAFOOD BUYERS TOWARD FARM-RAISED HYBRID STRIPED BASS
No full textA market survey of three mid-Atlantic food-fish market levels was conducted to provide information on finfish buyers' market characteristics, finfish attribute preferences, and buyers' attitudes toward farm-raised hybrid striped bass. Results showed that most firms are located in the suburban areas, and they purchased their fish from producers and wholesalers. Quality was rated as the most important finfish attribute; and, aside from restaurants, buyers are generally familiar with hybrid striped bass and indicated that it could easily be substituted for wild striped bass. Most buyers were either not sure or feel hybrid striped bass could not substitute for other fish species although they all expressed a willingness to offer farm-raised hybrid striped bass. Finally, the possibility of fish farmers selling directly to all market levels has great potential if the fish size is around two to three pounds and the form is whole for the wholesaler and retailer and fillet for the restaurants.Consumer/Household Economics,
Genetic variability of European sea bass, Dicentrarchus labrax L.: data from a hatchery stock
No full textFirst paragraph: European sea bass, Dicentrarchus labrax L,, is an important commercial species along the Atlantic and Mediterranean coastline in both fishing and aquaculture. The artificial propagation of this species may lead to reduced amounts of genetic diversity. Although many biological topics related to the aquaculture of this species have been studied (see Barnabe & Billard 1984), information on the amount and distribution of genetic variation throughout the range of the species is scarce
CHRONIC AFFECTS OF DETERGENT SURFACTANT (LINEAR ALKYLBENZENE SULFONATE / LAS) ON THE GROWTH AND SURVIVAL RATE OF SEA BASS (Lates calcalifer Bloch) LARVAE
No full textSea bass (Lates calcalifer Bloch) is one of the economically important marine fishes, which is getting more important for marine-culture. This fish is categorized as a euryhaline species, i.e. has a wide salinity tolerance range. This species can live in the sea with salinity between 32 – 35 ppt, and in the river, estuarine and mangrove areas with the salinity between 0 – 25 ppt. The adult sea bass spawn in marine waters and the larvae and juvenile are mostly found in the estuarine. Estuarine is known as a good nursery and feeding ground, however it is also known as a pollutant trap. Therefore, the larvae of seabass and other euryhaline species are very susceptible to this condition
Surfactant detergent Linear Alkyl-benzene Sulfonate (LAS) is a non-ionic soft detergent, which has a long straight carbon chain and a powerful cleaning capability. It is toxic to aquatic organisms, and however it is biodegradable. Therefore, it is widely used for cosmetic and household purposes. Some research found that the toxicity (LC50-96 hours) of LAS detergent on invertebrate Daphnia magna was 2.7 mg/l, on gastropods was 19.4 mg/l and on shrimp (Panaeus japonicus) was 4.5 mg/l. The acute and chronic effect of this detergent on tropical marine fish is not yet known.
This research was done to find out the chronic effect (LC50-96 hours) and acute effects, of detergent LAS on the larvae of sea bass (Lates calcaliver Bloch). A Bioassay method was applied to find out the acute toxicity, and Probit Analyses was used to find out the LC50-96 hours of detergent LAS on sea bass larvae. Randomized Design was used to observe the chronic effects on the growth, survival rate of the sea bass larvae. There were six treatments applied, i.e.: treatment A (0% of LC50-96 hours); B (5% of LC50-96 hours); C (10% of LC50-96 hours); D (15% of LC50-96 hours); E (20% of LC50-96 hours); F (25% of LC50- 96 hours). Analyses of variance were used to find out if there was a significant different in the treatment, followed by Multiple Range Duncan Test to find out the different among treatments. The histology of the gill and liver of the sea bass exposed to different concentration of detergent LAS was also observed.
The results showed that the LC50-96 hours of detergent LAS on sea bass larvae was 1.18 mg/l and
considered as moderately high toxicity. The absolute biomass growth of sea bass larvae was not affected by sub-lethal concentrations of detergent ALS, however, chronic concentrations of detergent LAS affected the daily growth rate of sea bass larvae significantly (p<0.01). As a conclusion, the acute toxicity of LAS detergent on sea bass (Lates calcaliver Bloch) larvae was 1.18 mg/l. The sub-lethal concentrations of detergent LAS on the sea bass larvae did not influence the biomass growth and survival rate but affected the daily growth rate of sea bass larvae significantly. The sea bass larvae exposed to the sub lethal concentrations of LAS detergent for 30 days resulted in the gill damage, i.e.: hypertrophy, hyperplasia, telengeastases and melanization of the gill. The congestion and vacuolar degeneration of the liver were also observed
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