bluuebunny/crossref_metadata_2025 huggingface dataset:
Metabolic effects of partial pancreatectomy in the Northern pike, Esox Indus L.
Authors: Ince B. W.
Published: January 2006

Metabolic effects of partial pancreatectomy (70%) after 1 month were studied in the Northern pike, Esox lucius L. Plasma protein and haematocrit levels were significantly reduced in the pancreatectomised fish when compared with sham‐operated controls. By contrast, however, blood glucose, plasma amino acid nitrogen and cholesterol levels remained unaltered.

The tolerance to intra‐arterial glucose and amino acid loading was compared in pancreatectomised and control fish. Pancreatectomy resulted in a significantly impaired clearance of amino acids from the plasma whereas glucose tolerance was similar in both groups. Neither glucose nor ketones could be detected in the urine of pancreatectomised pike after 1 month. These data indicate that partial pancreatectomy does not cause the development of a diabetic state in this species over a 1 month period.
Blood dyscrasia in a teleost, Colisa fasdatus after acute exposure to sublethal concentrations of lead
Authors: Srivastava A. K. , Mishra Shashikala
Published: January 2006

Colisa fasciatus, a freshwater teleost, were exposed for 90‐h to 15 mg l−1 (0.79 of the96‐h LC50 value) lead nitrate under static test conditions. The treatment resulted in decreased (P≤ 0.001) erythrocyte counts, haematocrits and haemoglobin contents of the moribund fish. Toxicity of the metal was also characterized by significant (P<0.001) acceleration in erythrocyte sedimentation rate, numerical increase in the number of immature erythrocytes in circulation, lysis and degeneration of erythrocytes, and an increase in the hepatosomatic index. Leucocyte and thrombocyte counts, the number of lymphocytes, and blood clotting times were not significantly different between experimental and control fish. Haemolytic anaemia and an overt increase of circulating immature erythrocytes can be used in monitoring lead poisoning in fish.
Some observations of the effects of body weight, temperature, meal size and quality on gastric emptying time in the turbot, Scophthalmus maximus (L.) using radiography
Authors: Flowerdew M. W. , Grove D. J.
Published: January 2006

The gastric emptying time (G.E.T.) in turbot was investigated using X‐radiography and was found to decrease with temperature. Small fish processed a given ration, expressed as percent body weight, faster than large fish (G.E.T. was found to be proportional to (fish weight)0.364). Large meals in a given fish were processed at a faster rate than small meals. Gastric emptying rate (G.E.R.) was found to be proportional to (meal size g)0.613 at 8° C and (meal size g)0.788 at 19° C. These exponents are in agreement with a recently proposed model relating G.E.T. and G.E.R. to meal size (Fänge & Grove, 1978). Large fish emptied a meal of given absolute size from the stomach at a faster rate (g h−1) than small fish. Experimental meals diluted with kaolin were evacuated in significantly less time than a control diet, suggesting that turbot may adjust feeding rates when food quality varies.
Some observations of rainbow trout, Salmo gairdneri, Richardson, infected with Cryptobia salmositica
Authors: Lowe‐Jinde L.
Published: January 2006

Rainbow trout (Salmo gairdneri) were infected with an inoculum of infected blood containing 106Cryptobia salmositica. Parasitaemia was cyclical with a major peak at 14–21 days and a smaller peak at 42 days. The first peak of parasitaemia was correlated with low glucose, plasma proteins, and haematocrit levels. During this time clinical symptoms (exophthalmia, ascites, pale liver and gills) of the pathogenic condition were observed. The partial disappearance of the parasites from the blood was corrrelated with their appearance in the peritoneal cavity. As plasma glucose, proteins, and haematocrit levels returned towards control values, the oedema and gill paleness declined. Examination of the liver and spleen showed an exudate of fibrous matrix on their exterior surfaces. In addition, the presence of 2–4×103 mm−3Cryptobia in asymptomatic surviving fish suggests that a chronic parasitaemia can be tolerated.
Amino acid incorporation by isolated oocytes of the marine teleost Blennius pholis L.
Authors: Shackley S. E. , King P. E.
Published: January 2006

The uptake of a labelled amino acid, tritiated leucine, by isolated oocytes of Blennius pholis L. is described. Uptake related to protein and RNA synthesis is distinguished by the use of two metabolic inhibitors. An endogenous contribution to the protein yolk is indicated but this may undergo turnover with time.
The survival of smolts of salmon Salmo salar L. at low concentrations of dissolved oxygen
Authors: Alabaster J. S. , Shurben D. G. , Mallett M. J.
Published: January 2006

The survival of Atlantic salmon smolts on sudden exposure to low constant concentrations of dissolved oxygen (DO) has been measured under laboratory conditions; the 3‐d LC50 is about 3 mg l−1 in freshwater and about 2.5 mg l−1 in 30% and 80%‘sea water’, even for fish acclimated for several days to low concentrations of DO and high salinity; median threshold concentrations of DO are probably close to 3.3 and 2.6 mg l−1 respectively.
Observations on the food and feeding habits of the African electric catfish Malapterurus electricus (Gmelin)
Authors: Sagua V. O.
Published: January 2006

The diet and feeding habits of the African electric catfish Malapterurus electricus in their natural habitat in Lake Kainji, and in the River Niger, downstream of Kainji dam, Nigeria, have been described and compared. The study showed the electric catfish is a voracious piscivore. It feeds on cichlids, clupeids, schilbeids and other available fish species. From the size distribution, numbers and composition of the small prey fish species examined in electric catfish stomachs, it was inferred that the powerful high‐frequency electric organ discharge volleys serve as major predatory mechanism.
Variability and stability of selected components in rainbow trout Salmo gairdneri serum and the precision of automated analysis in measuring these components*
Authors: Warner M. C. , Tomb A. M. , Diehl Sally A.
Published: January 2006

Eighteen components in rainbow trout serum were tested for variability among individuals and stability during storage. In addition, the precision of an automated serum analysis system was determined. Stability of serum components was observed over 42 days at temperatures of 25° C, 4° C and ‐ 10° C. Components tested included: albumin, total protein, blood urea nitrogen, cholesterol, chloride, glucose, potassium, sodium, cholinesterase, alkaline phosphatase, lactic dehydrogenase, a‐hydroxybutyrate dehydrogenase, glutamic pyruvic transaminase, phosphohexose isomerase, inorganic phosphorus, calcium, creatinine, and creatine phosphokinase. Fish serum was generally more stable than human serum when stored at 25° C and 4° C and similar in stability at ‐ 10° C. Precision of analytical methodologies was excellent for all components measured except creatine phosphokinase.
The food and feeding habits of greenback grey mullet, Liza subviridis (Valenciennes), from different habitats and at various stages of growth
Authors: Chan E. H. , Chua T. E.
Published: January 2006

An analysis of the stomach contents of Liza subviridis at various stages of growth and from different habitat types is given. Transitions in diet with respect to size were observed. Postlarval stages of less than 12 mm standard length fed only on zooplankton. The transition to bottom feeding occurred in specimens 16–20 mm, with food items consisting of zooplankton, diatoms, detrital material and inorganic sediment. The transition was complete on attaining a length of 24 mm whereby food items comprised diatoms, detrital material, filamentous algae and inorganic sediment. The relevance of this information in aquaculture is discussed. The stomach contents of adult Liza subviridis taken from different habitat types were consistent, comprising diatoms, detrital material and inorganic sediment. Filamentous algae was also consumed where available.
Some data on the basic metabolism of trout eggs
Authors: Czihak G. , Peter R. , Puschendorf B. , Grunicke H.
Published: January 2006

Oxygen consumption was found to be essentially the same in unfertilized trout eggs, water activated eggs and eggs immediately after fertilization. Trout eggs are capable of regulating the pH of the surrounding medium probably by releasing buffering electrolytes. The electrolyte composition of the coelomic fluid is close to normal vertebrate blood serum. The coelomic fluid may permit further growth of ovulated eggs before spawning.
The distribution and biology of the cestode Eubothrium parvum in capelin, Mallotus villosus, (Pallas) in the Barents Sea, and its use as a biological tag
Authors: Kennedy C. R.
Published: January 2006

Samples of Eubothrium parvum were obtained from capelin Mallotus villosus at 55 stations throughout the Barents Sea and from Balsfjord, North Norway. The parasite is distributed widely throughout the Barents Sea, but both incidence and intensity of infection are higher in the regions off Murmansk and the Kola peninsula, and Spitsbergen. E. parvum exhibits a seasonal peak in maturation and probably also in acquisition of new infections. The incidence of infection is greatest in 1 + fish, whereas the intensity is more independent of host age. It is suggested that the parasite requires only a single intermediate host, a plank‐tonic copepod, and its distribution in relation to age of host is a reflection of the dietary preference shown by young capelin for copepods. The frequency distribution of E. parvum in capelin was over‐dispersed in Balsfjord, where infection levels of between 1 and 28 parasites per fish were encountered in all samples, but under‐dispersed in the Barents Sea, where infections of more than four parasites per fish were never found and even infections with three and four parasites were very local. It is suggested that the underdispersion is due to a very low probability of infection in the open waters of the sea. Although the presence of E. parvum cannot be used as a biological tag for capelin, its abundance and frequency distribution can. The difference in frequency distribution and the failure to find any heavily infected fish in the Barents Sea confirm the suggestion that the capelin of Balsfjord form a local isolated population, which does not migrate into the Barents Sea. The differences in infection levels within the Barents Sea suggest the further possibility that there are at least two stocks of capelin there, but this requires further investigation and confirmation.
Distribution and development of rodlet cells in the gills and pseudobranch of the bass, Dicentrachus labrax (L)
Authors: Mattey D. L. , Morgan M. , Wright D. E.
Published: January 2006

Rodlet cells in various stages of development were found in large numbers in the bass gill and pseudobranch. In the gill, rodlet cells were found in the epithelium at the base of the secondary lamellae and on the filament between adjacent lamellae, whilst in the pseudobranch they were found over the whole area of the secondary lamellae as well as in the filament epithelium.

During early development, rodlet cells are characterised by their amorphous cell inclusions, prominent supranuclear Golgi complex and network of granular endoplasmic reticulum. Later, with formation of a fibrous border the arrangement of the cell organelles undergoes reorganisation; the endoplasmic reticulum becomes distended, numerous vesicles appear and the mitochondria aggregate in the apical region of the cell. One of the most striking features is the development of club‐shaped sacs containing electron dense cores, which are orientated towards the open apex of the cell.

Various staining properties of rodlet cells for light and electron microscopy were compared with those of mucous cells found in the same tissues. Possible functions of the cell are discussed.
Analysis of catch data from 1968 to 1976 from nine fish landings in the Kenya waters of Lake Victoria
Authors: Benda R. S.
Published: January 2006

Fish landing data collected by the Kenya regional fisheries officers from Homa Bay, Kaloka, Karungu, Marenga, Wichlum, Kendu Bay, Usenge, Dunga and Ngegu from 1968 to 1976 were statistically analysed to determine trends in the traditional fisherman's catch in the Kenya waters of Lake Victoria. Over the nine years a significant decline occurred for total catch and catches of Haplochromis spp., Tilapia spp. and Protopterus aethiopicus. Engraulcypris spp. catch increased significantly; while catches of Bagrus docmac and Clarias mossambicus fluctuated and no clearly defined trend emerged, although B. docmac catch seemed to be declining.

Overall indications were that as the catch of traditionally preferred fish declined, Engraulicypris spp., B. docmac, C. mossambicus and recently introduced Lates niloticus were becoming more important to the total catch.
Agonistic behaviour of age 0, age 1 and non‐breeding adult Arctic grayling Thymallus arcticus (Pallas)
Authors: Kratt L. F. , Smith R. J. F.
Published: January 2006

Age 0 Arctic grayling begin to show agonistic behaviour 3 weeks after emergence and are territorial by their fourth week. Age 1 fish are territorial throughout the summer feeding period. In adults, territoriality is restricted to larger males during the early spring breeding season while after the breeding season both smaller adult males and adult females also hold territories.

In sub‐adults, larger fish and resident fish tend to win most fights. In adults, males usually win against females. In fights between adults of the same sex, larger and resident fish usually win.

The lateral display becomes more important in the agonistic repertoire of Arctic grayling as they mature and the characteristic large dorsal fin develops. Arctic grayling appear to lack an appeasement display.
Digestion of an aquatic macrophyte by Tilapia zillii (Gervais)
Authors: Buddington R. K.
Published: January 2006

The digestive efficiency of Tilapia zillii fed Najas guadalupensis was studied in the laboratory. Digestion was dependent on the ability of the fish to triturate the plant tissues. Based on a dietary reference, cellulose, the total digestibility of Najas was 29.3%. Digestive efficiency of the fish for non‐cellulose organic matter, protein and fat was 55.7%, 75.1% and 75.9%, respectively. Of the total caloric content of the plant, 45.4% was assimilated. An estimate was made of the amount of Najas necessary to satisfy the caloric expenditure of the fish.
The occurrence of Aeromonas and Streptococcus in Rainbow Trout, Salmo gairdneri Richardson
Authors: Barham W. T. , Schoonbee H. , Smit G. L.
Published: January 2006

Smears were taken from the eyes, spleen and blood from rainbow trout collected from a fish farm and classified as clinically sick, under treatment, recovered and apparently healthy. The smears were examined microscopically and the bacteria present identified as Aeromonads or Streptococci. The results indicated a high incidence of Aeromonads in the eye and the spleen but not the blood in all groups including those apparently healthy while streptococci were present in the blood as well as the eye and the spleen.
‘Pear‐shaped’ cells in the digestive tract of the perch Percafluviatilis (L.)
Authors: Hirji K. N. , Courtney W. A. M.
Published: January 2006

Light and electron microscopy revealed the presence of ‘pear‐shaped’ cells amongst the mucosal cells of the stomach, pyloric curvature, pyloric caeca and the anterior‐most region of the intestines of perch. The cells are usually located in the distal region of the mucosa and are approximately half the height of the other mucosal cells. Electron microscopy shows that the cells are composed of thick outer sheaths which are fibrillar in appearance. The cytoplasm is characterized by electron dense rods numbering from three to fifteen, which originate from the supranuclear region of the cells and converge apically. The rest of the cytoplasm is composed of Golgi apparatus, secretory vacuoles, minute mitochondria and a network of cytoplasmic strands laden with ribosomes. The organization of organelles in these cells does not resemble that of other mucosal cells of the alimentary canal. Contrary to what has been suggested previously, the ‘pear‐shaped’ cells neither resemble nor represent stages in the formation and maturation of goblet cells.
Restoration of glycogen from lactic acid in the anaerobic swimming muscle of plaice, Pleuronectes platessa L.
Authors: Batty R. S. , Wardle C. S.
Published: January 2006

The conclusion from two in vivo experiments is that a significant proportion of the lactic acid, normally formed by glycolysis from glycogen and held in the muscle cells following exhausting exercise of the anaerobic swimming muscle of the teleost fish Pleuronectes platessa L, is converted by gluconeogenesis to form glycogen in the recovering muscle.

In the first experiment a technique for measurement of [3H]glucose turnover in the plaice was developed and applied to measure turnover in resting and exhausted fish. It is concluded that insufficient glucose was moved through the circulation to account for the rate of glycogen formation observed in the recovering exhausted muscle.

In the second experiment, an intramuscular injection of [14C]lactate to exhausted fish revealed a direct uptake of [14C]lactate by the recovering muscle cells, and the incorporation of substantial proportions of lactate into the restored glycogen. Simultaneous use of [3H]‐mannitol allowed measurement of the isotope distribution between extra‐ and intracellular spaces.
Red and white muscle fibre activity in swimming skipjack tuna, Katsuwonus pelamis (L.)
Authors: Brill R. W. , Dizon A. E.
Published: January 2006

To test the hypothesis that white muscle fibre portions of the myotomes are used at sustainable swimming speeds, skipjack tuna, Katsuwonus pelamis, were forced to swim against various current velocities in a water tunnel while electrical activity of the red and white muscle fibres was simultaneously recorded. Eight fish were tested, five fish graded white muscle fibres into activity at swimming speeds above their minimum hydrostatic equilibrium speed, but well below the estimated maximum sustainable swimming speed of skipjack tuna. Three other fish showed white muscle fibre activity at minimum swimming speeds, a possibly abnormal condition.
Preliminary observations on the near‐surface fish fauna of the northern North Sea in late autumn
Authors: Hislop J. R. G.
Published: January 2006

In the course of cruises by FRV Scotia to study the ecology of O‐group gadoids in the northern North Sea in October 1977 and November 1978, the fish fauna of the upper 1 m of the water column were sampled with an improvised gear. The most abundant species were O‐group rocklings and clupeids and three spined sticklebacks. The frequency of occurrence of the last named and their relatively high abundance (up to 99 individuals in a 30 min haul) suggests that sticklebacks are more widely distributed throughout the open North Sea than is presently supposed. Young rocklings may amount to a considerable biomass in the near‐surface waters.
Time of divergence of growth groups between potential 1+ and 2+ smolts among sibling Atlantic salmon
Authors: Thorpe J. E. , Morgan R. I. G. , Ottaway E. M. , Miles M. S.
Published: January 2006

Development of bimodality in the length frequency distributions of sibling juvenile Atlantic salmon, Salmo salar L., was observed in three experiments, using eight families in 25 tank populations. Divergence between the groups became evident in late summer or early autumn. The time of divergence, and the size offish at which this change took place differed between families.
Observations of rainbow trout, Salmo gairdneri Richardson, infected with Cryptobia salmostica
Authors: Lowe‐Jinde L.
Published: January 2006

Rainbow trout, Salmo gairdneri, were experimentally infected with Cryptobia salmositica. The parasitaemia was associated with increases in the size of the spleen, liver and heart (% body weight). The splenomegaly was pronounced and was often 600‐fold larger. The amounts of blood lactic acid and lactic dehydrogenase in the infected and control fish were similar. However, glycogen levels of the liver, heart and epaxial muscle declined. Liver glycogen levels were most affected and decreased to values which represented 20% of the control values. The pattern of the glycogen levels of the liver, heart and epaxial muscle declined to rise to normal values by day 56 post‐inoculation. Thus, the glycogen levels both paralleled the acute parasitaemia and the subsequent partial recovery of the infected fish as they tolerated a low chronic parasitaemia.
Nuclear diameter as a criterion of adrenocortical activity in a teleost fish Coregonus lavaretus (L.)
Authors: Scott D. B. C. , Rennie S. E.
Published: January 2006

A direct comparison of plasma cortisol levels and mean nuclear diameter of adrenocortical cells in the same fish was carried out, to determine whether nuclear diameter could be used as a valid criterion of adrenocortical activity in Coregonus lavaretus (L.). Specimens were caught and killed by a variety of methods and at different seasons, providing a range of plasma cortisol concentrations, which were measured by gas‐liquid chromatography. The head‐kidneys of the same fish were immediately fixed and the diameters of 20 adrenocortical cell nuclei measured in 7 μm sections of each, prepared by strictly standardized methods. The correlation coefficient was 0·54, so that nuclear diameter cannot be regarded as an accurate criterion of adrenocortical activity.
Studies of the biology of the lesser weever fish, Trachinus vipera Cuvier II. Distribution
Authors: Lewis D. B.
Published: January 2006

The distribution of Trachinus vipera, worldwide and around the British coast, is summarised. Field observations indicate that the fish occurs throughout the intertidal zone; is more active at low light intensities, and can survive the low tide period buried in the intertidal sand; can tolerate salinities as low as 19%0, for short periods; exhibits a tidal periodicity, is more active on the flood tide than the ebb tide; moves into deeper warmer water in winter, the extent.of the movement being temperature dependent. The critical temperature initiating this movement is probably 5deg; C. The fish is not available for capture in cold weather, because it may be hibernating, buried in the sand.
Comparative tissue ascorbic acid studies in fishes
Authors: Agrawal N. K. , Mahajan C. L.
Published: January 2006

Comparative tissue ascorbic acid levels in four species of major carp viz., Labeo rohila, L. calbasu, Cirrhina tnrigala and Catla catla, were investigated. The ascorbic acid level was found to be the highest in the spleen in the four species studied (range 430–380 μg/g) followed by the anterior (adrenal) kidney, gonads, liver, renal kidney, brain and/or eye. Heart and blood had the lowest levels (range 26–18 μg/ml) amongst the tissues studied. Overall tissue ascorbic acid levels were the highest in L. rohita and the lowest in C. mrigala. Investigation on seasonal variations in blood and kidney ascorbic acid levels of Notopterus notopterus revealed peak levels in spring (February‐April) and the lowest levels in the postspawning period (August‐September).
Factors affecting the distribution of juvenile estuarine and inshore fish
Authors: Blaber S. J. M. , Blaber T. G.
Published: January 2006

The differential distributions of juveniles and adults of 25 species of teleost were investigated and compared from four habitat types in sub‐tropical Moreton Bay, Queensland. The aim of the study was to identify factors influencing the distribution of juveniles, particularly the species which enter estuaries. The following habitats were sampled: a shallow, sheltered tidal estuary (Caboolture); a shallow, exposed bay with muddy substrates (Deception Bay); an exposed area of sandy substrates and seagrass (Toorbol Point) and a sheltered oceanic site with sandy substrates and seagrass (Kooringal). Data on diet, spawning seasons and recruitment periods of fry are presented together with measurements of salinity, temperature and turbidity. Species entering estuaries recruited mainly in summer (rainy season). The possible preference of juveniles for calm water, the roles of food and predation pressure, the effects of salinity, temperature and turbidity are discussed in relation to the biology and distribution of the fish. Salinity and temperature were probably not important to most juvenile fish. The effects of calm water, suitable food and predators vary according to species. Although all juveniles studied preferred shallow water, in the case of those entering estuaries, turbidity was the single most important factor. Juveniles of the same species occurred in both the estuary and Deception Bay where abiotic and biotic factors other than turbidity were different. During summer, turbidity gradients extended from east to west in Moreton Bay with highest turbidities in Caboolture estuary and Deception Bay. In winter, turbidities throughout Moreton Bay were low and relatively uniform. At this time many of the ‘clear water’ species occurred in Deception Bay. The influence of high turbidity on fish may be linked to reduced predation pressure and perhaps food supply in shallow water. Turbidity gradients in summer may aid fry in locating estuarine nursery grounds. It is apparent however, that juveniles of many species are probably not attracted to estuaries per se but to shallow turbid areas.
The growth and reproductive strategy of the gudgeon, Gobio gobio (L.), in two hard‐water rivers in southern England
Authors: Mann R. H. K.
Published: January 2006

Scales from 682 gudgeon from the River Frome and 504 from the River Stour were used for age determinations. Growth in length was confined to the period May to October, but some weight increase occurred during the winter because of gonad development. Growth rates in the two rivers were the same, and were higher than most of those reported from other European rivers. Wide fluctuations, up to 12‐fold, occurred in the year‐class strengths of Frome gudgeon, caused by variations in the survival of juvenile gudgeon in their first year of life. Density‐independent factors, particularly water temperature, were major influences. Female gudgeon grew marginally slower than the males, but they matured earlier and at a smaller size. They were fractional spawners but their total reproductive effort each season was high. Both sexes had low survival rates and their reproductive life spans were rarely more than three years. These life history traits support the premise that these gudgeon populations are r‐selected.
The effect of training on the lateral musculature of O‐group roach, Rutilus rutilus (L.), and their fatigue in subsequent exercise tests
Authors: Broughton N. M. , Goldspink G. , Jones N. V.
Published: January 2006

First year roach from a Stillwater habitat were maintained in an’artificial stream for periods of up to 40 days and samples of the lateral musculature were subjected to histological examination. It was found that there was a highly significant increase in the percentage of red muscle present in the hindermost regions of the fish confined for 30 days or more in the stream. In subsequent exercise tests, it was shown that the FV50 was higher for fish conditioned for 40 days, but it was considered unlikely that this increase in swimming ability was as a direct result of changes in muscle composition.
The detection of dissolved amino acids by the Atlantic cod, Gadus morhua L.
Authors: Johnstone A. D. F.
Published: January 2006

A classical conditioning technique was employed with cod, Gadus morhua L., to determine thresholds for the detection of the L‐forms of some α amino acids which are thought to be attractants or feeding stimulants for fish. The amino acids investigated, in order of effectiveness, were tyrosine, cysteine, phenylalanine, glycine and methionine with mean threshold response levels ranging from 2·5 × 10‐8M to 7·4 × 10‐8M. Histidine and lysine resulted in similar thresholds with a mean value of approximately 3 ± 10‐7M while taurine and leucine were least effective with mean threshold levels of 2·1 × 10‐6M and 2·1 × 10‐5M respectively. Comparison is made with electrophysiological and behavioural response data from other species. The effect of raising the background level of glycine on the threshold to glycine for cod is described. The results are discussed with reference to data on levels of dissolved free amino acids in shallow sea waters which may have a bearing on determining chemosensory threshold levels. To detect a specific amino acid against a background level of the same substance the difference in level for detection is proportionally greater for higher background concentrations.
The haematological assessment of bacterial infection in rainbow trout, Salmo gairdneri Richardson
Authors: Barham W. T. , Smit G. L. , Schoonbee H. J.
Published: January 2006

The pH, pCO2 and pO2 values for diseased fish did not differ significantly from those values for healthy fish, but fish treated with terramycin showed a highly significant rise in pCO2 with a corresponding fall in pO2. Haematocrit values, as well as haemoglobin and total plasma protein concentrations were significantly lower in diseased fish while treated fish showed a significant rise in total plasma protein. Glucose concentrations fell very significantly in diseased fish and showed a significant increase in treated fish.

The plasma electrolytes, sodium, potassium and chloride, were significantly reduced in diseased fish and potassium levels also fell in treated fish. Diseased fish showed very significantly reduced erythrocyte counts. Of the three parameters MCV, MCH and MCHC, only the values for MCH in diseased fish differed significantly from those for healthy fish.
The shore fishes of Ascension Island
Authors: Lubbock R.
Published: January 2006

Seventy‐one species of shore fishes are recorded from Ascension in a checklist which includes notes on ecology and behaviour. The extraordinary abundance of blackfish, Melichlhys niger, and the aggressive nature of moray eels, Lycodontis moringa, towards man are briefly mentioned. The number of species recorded is low for a tropical island and seems to reflect Ascension's geographical isolation and lack of habitat diversity; 15·7% of Ascension shore fishes (excluding one fish not identified to species level) appear to be endemic to the island, with a further 17·1% known only from Ascension and St Helena; 30·0% are recorded only from the western and central Atlantic, while 7·1% are recorded from the eastern and central Atlantic; 30·0% are widespread Atlantic species. Two new species are described: Taenioconger camelopardalis and Helcogramma ascensionis.
Energetics of the annual reproductive cycle in female sticklebacks, Gasterosteus aculeatus L.
Authors: Wootton R. J. , Allen J. R. M. , Cole S. J.
Published: January 2006

Laboratory studies on the thrce‐spined stickleback provided predictive equations for the relationships between food consumption, faecal production and growth, and between respiration rate and body weight. These equations were used to estimate the energy income and expenditure at monthly intervals during the annual reproductive cycle of females of mean length from two populations. In winter only a small percentage of the energy income was invested in ovarian or somatic growth, and the latter was negative in some cases. Routine respiration and faecal losses accounted for a high proportion of the energy income. In spring a higher proportion of the energy income was partitioned into somatic and ovarian growth while routine respiration accounted for a smaller proportion of the energy income.
Stomach contents analysis—a review of methods and their application
Authors: Hyslop E. J.
Published: January 2006

Methods for analysing fish stomach contents are listed and critically assessed with a view to their suitability for determining dietary importance—this term is defined. Difficulties in the application of these methods are discussed and, where appropriate, alternative approaches proposed. Modifications which have practical value are also considered. The necessity of linking measurements of dietary importance to stomach capacity is emphasized and the effects of differential digestion upon interpretation of stomach contents outlined. The best measure of dietary importance is proposed as one where both the amount and bulk of a food category are recorded.
Growth‐rate and smolting‐rate of progeny of male Atlantic salmon parr, Salmo salar L.
Authors: Thorpe J. E. , Morgan R. I. G.
Published: January 2006

In experiments conducted in two successive years, the progeny of male Atlantic salmon parr (Salmo salar L.) were found to grow in length at the same rate as the progeny of sea‐run males. The proportions of these populations which smolted at one year old did not differ in the first experiment, but were significantly higher among progeny of parr (33%) than among progeny of sea run‐adults (21%) in the second year. Survivals throughout the experiments were high, at 89 and 91% respectively in the two years. A possible inhibitory relationship between smolting and sexual reproduction in the same year is discussed.
Survival and reproductive performance of the desert pupfish, Cyprinodon n. nevadensis (Eigenmann and Eigenmann), in acid waters
Authors: Lee R. M. , Gerking S. D.
Published: January 2006

Desert pupfish, Cyprinodon n. nevadensis, were exposed to pH levels of 8·3 (control), 7·0, 6·5, 6·0, 5·5 and 5·0 to determine the effects of acidity on reproduction. Egg production was significantly reduced at every pH level tested below the control. Egg‐laying virtually ceased at pH 5·0, while egg viability was reduced to less than 50% of the control value at pH 6·5, when eggs were tested at the same pH at which they were laid. The 96 h LC50 for this species was pH 4·56, considerably below that for successful reproduction. Larvae were less tolerant to acid stress than were adults.

Acclimation of reproductive performance to increased acid levels did not occur. Reproductive performance did not fully recover to control levels when the fish were placed in more favourable conditions after prolonged exposure to low pH.

Reduction in the number and development of oocytes was observed in the ovaries of acid stressed fish resulting in the decreased reproductive potential.
‘Growing season’ as a factor in sea trout production
Authors: Fahy Edward
Published: January 2006

Correlations between mean age at smoltiftcation (MSA) of sea trout post‐smolts and length of growing season are presented. The first year of the two‐year smolt phase is the more important but the second is also significant as is the year of migration (the third). Strongest correlations are for MSA and the total number of growing days in all three years. A continuous record of calculated MSA from 1916–71 suggests there should have been relatively larger bursts of sea trout production in the 1940s and between 1955 and 1965. The number of trout migrating from one catchment correlates significantly with the number of growing days in the two‐year smolt phase.
Eubothrium crassum in migratory trout, Salmo trutta L., in the sea
Authors: Fahy Edward
Published: January 2006

The incidence and intensity of infection of various ages and conditions of migratory trout by Eubothrium crassum are described. A marine source of the worm seems likely and explanations for the characteristics of the parasite burden are given on this assumption. Within weeks of first going to sea the hosts accumulate large numbers of the parasite. One year suffices for the life cycle of Eubothrium but growth continues for at least two years and possibly for longer. The parasite burden decreases in older fish because of the stress imposed on the parasite by successive migrations of the host to and from fresh water and because older fish tend to feed earlier in the year.
The spawning migration of the brook lamprey, Lampetra planeri Bloch, in a South Swedish stream
Authors: Malmqvist B.
Published: January 2006

The spawning migration of brook lampreys (Lampetra planeri, Bloch) was investigated in a South Swedish lake and stream system for two consecutive years. The nightly variations were analysed by a multiple regression technique. In one of the seasons, characterized by frequent rain storms, water level was the most important factor explaining 60% of the observed variation in migration. In the following year, when the migration period was unusually dry, temperature and on‐shore winds at the mouth of the stream were the most influential environmental variables explaining 50% of the observed changes in behaviour. When data were combined for the two years only temperature showed a significant influence. The critical temperature for the onset of migration was estimated to be 7.5°C. Size distributions and sex ratios of the migrating lampreys, which are semelparous, indicated that the age distribution was complex and that females were older than males. Migration was essentially nocturnal, but late in the season day migration was also observed. A marking experiment resulted in few recaptures probably because of high predation and/or orientation difficulties.
Abscessed bony areas on Acanthopagrus cuvieri (Day) as a substrate for epiphytic algae
Authors: Tareen I. U.
Published: January 2006

Enteromorpha compressa (L.) Greville and E. clathrata (J. Agardh), widely distributed green algae in Arabian Gulf, were observed growing on Acanthopagrus cuvieri (Day). Abscessed areas on the operculum provided suitable sites for attachment of both species of algae; broken spine tips were preferred by E. compressa. This study showed that these algae preferred hard substrata, with no scales for attachment. E. compressa appeared earlier and grew faster. The condition of the fish was normal.
Enzymatic survey of four populations of Atherina boyeri based on electrophoresis and the occurrence of a microsporidiosis
Authors: Berrebi P. , Britton‐Davidian J.
Published: January 2006

Biochemical genetics of a Atherinid species, Atherina boyeri were undertaken to determine variability. Among the 17 loci studied, 7 were polymorphic, of which three were retained for a more detailed comparison of populations inhabiting the French Mediterranean coastal lagoons. A microsporidiosis is present in these fishes and is limited to certain lagoons. Comparison of allelic frequencies at the polymorphic loci between fish populations of infected and healthy lagoons yielded no significant differences. Several hypotheses are discussed and attempt to agree parasite distribution with genetical results.
A study of the histology and morphology of the digestive tract of the common eel (Anguilla anguilla)
Authors: Clarke A. J. , Witcomb D. M.
Published: January 2006

The anatomy and morphology of the digestive tract of the eel was examined using light and scanning electron microscopy. The oeosphagus showed complex longitudinal folding; stratified epithelium, columnar epithelium and goblet cells striated muscle fibres formed the thick muscular coat. The pneumatic duct entered the oesophagus anterior to the oesophagastric junction. The Y shaped stomach showed large well developed folds which decreased in size and number towards the pyloric sphincter. Columnar epithelium and gastric gland cells were present, the latter being absent from the pyloric region.

The intestine had a heavily thickened anterior region, signs of convulation were noted prior to the ileorectal valve. Intestinal folding showed a complex reticulate pattern with columnar epithelium and goblet cells present. The mucopolysaccharides were studied in the goblet and columnar cells throughout the regions of the gut. Lymphocytes and eosinophilic type cells were found in the connective tissue of the mucosa throughout the gut. The pancreas was a compact organ with few Islets of Langerhans, beta cells were peripherally situated and alpha cells centrally. The unilobular liver acted as a storage organ for oil and glycogen.
The effect of bacterial infection on erythrocyte fragility and sedimentation rate of rainbow trout, Salmo gairdneri Richardson
Authors: Barham W. T. , Smit G. L. , Schoonbee H. J.
Published: January 2006

Osmotic fragilities and erythrocyte sedimentation rates (ESR) were measured in healthy, diseased, treated and recovered trout, Salmo gairdneri. Bacterial infection with Aeromonas and Streptococcus resulted in more fragile erythrocytes and raised ESR values. Treatment with antibacterial agents improved the values of both parameters. Possible reasons for such changes are discussed. Caution in the use of apparently healthy fish for the unqualified interpretation of haematological results is expressed.
Factorial analysis of an experimental comparison of three methods of fishing for rainbow trout, Salmo gairdneri Richardson, in still water
Authors: O'Grady K. T. , Hughes P. C. R.
Published: January 2006

A three day experiment compared angling returns for rainbow trout, Salmo gairdneri Richardson, using fly, spinner and worm fishing methods. The catches of these methods were most similar on the first day: 3.36/h, 2.61/h and 3.75/h for spinner, fly and worm fishing, respectively. Catch rates on subsequent days declined, but less so for worm fishing. Overall, the worm fishing method returned the highest catch rate and estimates of catch rates for a year on a trout fishery also indicated that this method returned the highest catch rate.
Studies on the nature of the Z‐discs in skeletal muscle fibres of sharks, Etmopterus spinax L. and Galeus melastomus Rafinesque‐Schmaltz
Authors: Slinde E. , Kryvi H.
Published: January 2006

The ultrastructural details of Z‐discs from red, intermediate, and white axial muscle fibres from the sharks Etmopterus spinax and Galeus melastomus are described. Red fibre Z‐discs contain the most amorphous matrix material, and are thicker (100–115 nm) than intermediate (85–88 nm) and white Z‐discs (75–80 nm). Four sets of oblique bars extend tangentially from each thin filament. In each set two bars are present, those of white fibres are close together (approximately 5 nm), while those of red fibres are separated by a distance of 15 nm. A model of shark Z‐disc structure is proposed. The denaturation (heat transition) temperatures of the muscle proteins were studied by differential scanning calorimetry (DSC). The heat transitions of collagen, actin, and myosin were identified; the actin heat transition temperature increased in the sequence red, intermediate, and white. The total protein pattern of red and white muscle were studied by SDS electrophoresis. A protein with a molecular weight of about 55000 may represent a Z‐disc protein.
Genetic differences between the Chinese and the European races of the common carp III. Gonad abnormalities in hybrids
Authors: Hulata G. , Moav R. , Wohlfarth G.
Published: January 2006

Abnormalities in the gonads of carp, Cyprinus carpio L., were present in a relatively high proportion of hybrids derived from the Chinese and European strains. The aberrations involved were the absence or marked reduction of the gonads in mature fish.
Effects of temperature and photoperiod on ovarian recrudescence in the cyprinid fish Mirogrex terrae‐sanctae
Authors: Yaron Z. , Cocos M. , Salzer H.
Published: January 2006

Mirogrex terrae‐sanctae is a commercial, sardine‐like cyprinid fish in the Sea of Galilee. The fish spawns from December to the end of March. Females collected at the quiescent phase of the cycle (June) were exposed to four combinations of photoperiod and temperature for 3 months. The highest GSI (2.44 ± 0.22) was found in females exposed to simulated winter conditions (16°C, 9L) while the lowest GSI (0.65 ± 0.04) was found in fish exposed to simulated summer conditions (27°C, 14L). The GSI of fish maintained at the unnatural combination of 16°C, 14L (1.30 ± 0.09) did not differ from that of fish maintained at the other unnatural combination of 27°C, 9L (1.07 ± 0.11). However, histological examinations revealed that vitellogenic oocytes were present only in fish maintained at low temperature regimes, which implies that the growth of the ovarian mass in the 27°C, 9L group was due mainly to oogonial proliferation and that vitellogenesis was inhibited in Mirogrex at a high temperature.

Both protein and calcium concentrations increased in the serum of fish following injections of oestradiol‐17β. The increase of calcium was evident only in the non‐filtrable (bound) fraction, suggesting that the total serum calcium above 13 mg% could be used as an indirect parameter for circulating vitelloprotein.

Fish collected at the quiescent phase were injected with oestradiol (50 μg/fish c. 15 g body weight) and subsequently transferred to tanks maintained at either 12°, 20° or 27°C. The total serum calcium increased to 23.0 ± 1.75 mg% in the fish maintained for 8 days at 20°C. This was significantly higher than the concentration of calcium in the serum of fish maintained at either 12°C (7.8 ± 0.52) or 27°C(l1.8 ± 0.77). This implies that the temperature may affect ovarian recrudescence by modulating the response of the liver to oestrogen, allowing the oestrogen‐induced vitellogenesis to be relatively high in the cool environment during winter.
Haematological characteristics of albacore, Thunnus alalunga (Bonnaterre), and skipjack, Katsuwonus pelamis (Linnaeus)
Authors: Alexander N. , Laurs R. M. , McIntosh A. , Russell S. W.
Published: January 2006

Observations on haematological characteristics of albacore, Thunnus alalunga, and skipjack Katsuwonus pelamis, tunas, were made on blood samples collected from specimens immediately after they were caught and from an immobilized, restrained albacore sampled serially over a 24 h period. Results indicated eight types of blood cells in the peripheral circulation of both species. Lymphocytes were the most common leucocyte followed, in decreasing order, by neutrophils, eosinophils and monocytes in fish sampled immediately after being landed. Variations in differential and total white blood cell counts were observed in the immobilized, restrained albacore. High packed cell volumes and haemoglobin concentrations, typical for fast swimming fishes, were found in both species. Red blood cell counts were similar to those of other teleosts, and reticulocytes expressed as a percentage of mature erythrocytes were 6.1% and 5.2% for albacore and skipjack, respectively.
The response of the haemoglobin system of fed and starved rainbow trout, Salmo gairdneri Richardson, to bleeding
Authors: Lane H. C.
Published: January 2006

Seven days after a 15% reduction in blood volume by bleeding, the haemoglobin system of rainbow trout showed a modification in relative abundance of two of the four haemoglobins present in the haemolyate. The least anodic non‐Root effect haemoglobin increased proportionally whereas the major component, with its Root effect properties, showed a decline. A total of 30 days of starvation did not influence the relative proportions of the fractions. However, bleeding of these starved S. gairdneri provoked a shift similar to that of fed trout. In this case, however, both non‐Root haemoglobins, and the minor Root fraction, increased proportionally. The major Root fraction declined. The response of the starved group was more acute since all four components were significantly affected in contrast to two fractions in fed animals.
Hydrodynamics of suction feeding of fish in motion
Authors: Weihs D.
Published: January 2006

Forward motion was shown to increase the efficiency of suction feeding by causing the ingested volume to be predominantly in front of the fish, instead of being a sphere centred on the fish mouth. This increases the distance from which a prey, located in front of the predator, can be ingested by suction.

A general hydrodynamic model of the external effects of the suction process is presented, showing that this is dependent upon a single non‐dimensional parameter, the ratio of a characteristic mouth dimension, divided by the forward swimming speed and the suction time. Data for large‐mouth bass, Micropterus salmoides show that the observed average forward velocity while feeding, of 3.1 body length/s, serves to increase the ingestion range by more than 60% over suction while not moving.