bluuebunny/crossref_metadata_2025 huggingface dataset:
Suspected terrestrial deposition of eggs by Neochanna apoda Günther (Pisces: S almoniformes: Galaxiidae)*
Authors: Eldon G. A.
Published: January 2006

A description is given of the finding of eggs of Neochanna apoda distributed above the waterline in an aquarium. Actual spawning has not been observed. but the probability of terrestrial deposition of eggs by the fish in its natural enrivonment is recognized, and the possible ways in which this may be accomplished are discussed.
D(+)‐Glucose permeability in brown trout Salmo trutta L. erythrocytes
Authors: Bolis L. , Luly P. , Baroncelli V.
Published: January 2006

D(+)‐Glucose penetration in trout erythrocytes was studied with osmotic and tracer methods.

Results give no evidence for a carrier mediated diffusion system like that concerned with glucose permeability as in human red cells. The data show that glucose fails to stimulate erythrocyte respiration.
A field trial with the molluscicide Frescon* for control of Lymnaea peregra Müller, snail host of Diplostomum spathaceum (Rudolphi)
Authors: Crossland N. O. , Pearson A. J. A. , Bennet M. S.
Published: January 2006

Larval stages of the parasite Diplostomum spathaceum cause blindness in rainbow trout Salmo gairdneri (Richardson.) The adult parasite is found in the intestine of various species of gulls, and larval stages are found in various species of snails belonging to the genus Lymnaea.

A field trial was carried out at Lodge Reservoir, near Chelsmford, Essex to test the effectiveness of chemical control of the snail Lymnaea peregra. The molluscicide, Frescon, was applied in the first instance to the whole of the reservoir to give a concentration of 0.025 p.p.m. in the water using a motorized applicator mounted at the rear of a small boat. A second treatment was carried out when only the periphery of the lake was sprayed to a distance of 5 m from the banks to give a concentration of 0‐1 p.p.m.

No L. peregra were found in samples taken 10 days after the second application of Frescon and it is concluded that this snail had been virtually eliminated from the reservoir. No mortality of trout was observed. Some of the sticklebacks Gasterosteus aculeatus L. were killed and this may be attributable to uneven distribution of molluscicide near the margin of the reservoir. There were no apparent side‐effects on aquatic invertebrates or other wild life.

Five months after treatment some re‐population of the shoreline by L. peregra was observed, and applications of Frescon may therefore need to be repeated on several occasions during the season to maintain an effective level of control. However, where snail pests are confined mainly to the margin of such bodies of water, peripheral treatment may be effective and would be relatively inexpensive.
Production and food consumption of predatory fish in the Vistula River
Authors: Backiel Tadeusz
Published: January 2006

Vital statistics for six predatory fish species occurring in the Vistula River were estimated. The mixed, six species population, in its predatory phase, had an average biomass of 0‐96 g/m2 and produced 043 g/ma. Less than 45% of annual production was exploited by man and eggs shed amounted to about 10% of the production. Annual consumption by the population amounted to about 3 ‐44 kcal or g/ma. Accuracy of all estimates is low.
A simple electrically‐operated feeder for use in salmon rearing
Authors: Minaur J.
Published: January 2006

The construction of a simple, automatic feeder designed to dispense dry food used in salmon rearing is described. The feeder is powered by a 12 V battery and controlled by two electric clocks. Frequency of feeding, the daily duration of the feeding period, and the quantity of food dispensed can be adjusted.
Effects of stress on carbohydrate metabolism in the teleost Notopterus notopterus (Pallas)*
Authors: Narasimhan P. V. , Sundararaj Bangalore I.
Published: January 2006

The effects of different types of stre35 on carbohydrate metabolism in N. notopterus were investigated. Starvation alone brings about a signifiant increse in the glycogen content of the saccus vasculosus and a significant decrease in the brain glycogen concentration. The increased glycogen concentration in the saccus vasculosus may be a device to safeguard the brain against glucose deficiency during starvation stress. Rapid depletion of the muscle glycogen following fasting shows that the muscle glycogen IS the readily utilizable source of energy during starvation.

Exposure of N. noropierus to air brought about an increaSe in the liver glycogen and blood glucose levels but did not affect other paramcters studied.

Physical exhaustion of N. notopierus is noticed within 1–2 min of exercise. The readily available source of energy for exercise is the muscle glycogen. and the lactic acid produced is probably metabolized in the muscle itself. Saccus vasculosus glycogen. though inde‐pendent of changes in the blood glucose levels, may possibly be controlled by variations in the brain glycogen.
The syntypes of the sciaenid Corvina albida Cuvier and the status of Dendrophysa hooghliensis Sinha and Rao and Nibea coibor (nec Hamilton) of Chu, Lo & Wu
Authors: Trewavas Ethelwynn
Published: January 2006

Day (1876) rightly used the name Corvina albida Cuvier for a species with a pair of one on either side of the median pore of the lower jaw, and Dendrophysa hooghliensis Sinha & Rao (1969) is a synonym of it. Following Talwar (1970c), it may be known as Daysciaena albida. Reports of ‘Pseudosciaenu’ albida or Nibea cuibor from the western Pacific are of this species, but at least some refer to a Nibea, here renamed Nibea chui. The genus is redefined to exclude species without a cephalic extension to the swim‐bladder and a generic name is proposed for ‘Nibea’ diacanthus (Lacépède). A key to the species of is given.
Chromosome numbers of fishes. I
Authors: Gyldenholm A. O. , Scheel J. J.
Published: January 2006

The published chromosome numbers for 208 temperate and tropical freshwater fishes have been compiled in alphabetical order within the families. This facilitates the work for ichthyologists interested in the karyotype(s) of a particular species, genus or family as well as giving an overall account of the basic chromosome numbers and karyological trends in fishes.
Adrenaline induced changes in the metabolism of glycogen in the teleost retina
Authors: Drujan B. D. , Díz Borges J. M.
Published: January 2006

A study on the influences of adrenaline upon the metabolism of glycogen in fish retina is presented. The glycogen in the retina of the fish Eugerres plumieri amounted to approximately 7·5 mg glucose/10 g tissue wet weight of which 5·8+0±81 S.D. was present in the lyo‐form and 1·7+0·41 S.D. in the desmo‐form. The phosphorylase A activity in this tissue was found to be 36·5 μg P/g tissue wet weight/min, which represents 68 % of the total phosphorlyase activity. A definite effect of administered adrenaline upon the retinal glycogen could be observed only when conditions facilitating the penetration of this substance into the retina were given. A dose of 100 μg/kg body weight of adrenaline injected to the animals previously pretreated with 10 mg/kg of isocarboxazid and 20 ml of 20% v/v aqueous solution of ethanol showed a significant increase in phosphorylase activity and a close to 50% drop in the retinal lyo‐glycogen. The highest penetration of adrenaline into the retina was observed 20 to 40 min after the injection of adrenaline into a fish pretreated with isocarboxazid 4 h and ethanol 20 min prior to the administration of the amine. Under these conditions the glycemia went up from 70mg% to 90mg% and the MAO‐activity dropped from a value of 85 ug 4 HOQ/g tissue wet weight/30 min to zero.
Some effects of low oxygen tensions on the distribution of the three‐spined stickleback Gasterosteus aculeatus L. and the nine‐spined stickleback Pungitius pungitius (L.)
Authors: Lewis David B. , Walkey M. , Dartnall H. J. G.
Published: January 2006

During extensive sampling of populations of sticklebacks for parasites, it became apparent that marked differences existed in the distribution of the 2 British freshwater species. Observation of the survival, respiratory rates and distribution of three‐ and nine‐spined sticklebacks from a variety of habitats supports the suggestion that physiologically, the nine‐spined stickleback is much better adapted to life in closed, shallow, weedy, eutrophic waters, depleted in oxygen. By comparison, Gasterosteus aculeatus favours more open well oxygenated water.
Notes on helminth parasites of the whiting Odontogadus m. merlangus (L.) from the northern Irish Sea
Authors: Shotter R. A.
Published: January 2006

In an examination of 1352 whiting from the Irish Sea 13 helminth species were discovered. One species, Scolex polymorphus Rudolphi, was a new species associated with whiting and 7 other species were new species for whiting from the Northern Irish Sea. The species of the digenean genus Podocotyle found in whiting is probably an ecotype of P. atomon. It was concluded that the bothridial structure of 5. polymorphus cannot be used for diagnostic purposes nor to determine early and late stages of the larvae. The number of Diclidophora merlangi Kuhn (Monogenea) from each monthly sample with eggs in the uterus is directly proportional to temperature, but egg production under experimental conditions was greatest at 6° C. Several theories are proposed to explain these apparently contradictory observations. The life‐history of the digenean Stephanostomum pristis Looss, appears to be unusual in that the 2nd intermediate host may be planktonic. The nematode Contra caecum clavatum Rudolphi is found both as larvae and adults but larvae comprise the greater part of the worm population. The discovery of small stage II larvae in the stomach of whiting supports the theory that only one intermediate host is necessary for the development of Contmcaecum. There were significantly more female C. clavatum than male but a 1: 1 sex ratio is demonstrated by the acanthocephalan Echinorhynchus gadi Muller. Early and late forms of the plerocercoid of Grillotia erinaceus Van Beneden are identified. The early form occurred predominantly in the young whiting.
Compensatory swimming in the kokanee and sockeye salmon Oncorhynchus nerka (Walbaum)
Authors: Harvey H. H. , Bothern C. R.
Published: January 2006

When negatively buoyant, such as by increased pressure or loss of swimbladder gas, kokanee and sockeye salmon (Oncorhynchus nerka) attempt to swim upward by increased use of the pectoral fins. This response is termed compensatory swimming. Prior to initial filling of the swimbladder, sockeye fry showed no behavioural response to pressures above atmospheric. Following air‐gulping at the surface and bladder inflation, kokanee and sockeye fry responded to increased pressure by assuming a more vertical position and by beating the pectoral fins more rapidly. In young sockeye this response occurred over the pressure range of atmospheric to 20 lb/in2, and the effect of this behaviour would be to distribute these fish in the upper 14 m of the lacustrine environment. Fingerling kokanee showed a more gradual increase in compensatory swimming over the range of pressure equivalent to depths of 0–50 m. The behaviour of yearling kokanee would tend to concentrate these fish in the upper 30 m. Sockeye older than 1 year responded to negative buoyancy with increased horizontal swimming whilst planing upward on the pectoral fins. Depth distribution postulated on the basis of pressure‐induced compensatory swimming is consistent with the known vertical distribution of kokanee and sockeye salmon.
Studies on oral glucose intolerance in fish
Authors: Palmer T. N. , Ryman Brenda E.
Published: January 2006

The oral glucose tolerance test, a diagnostic procedure used in the detection of human diabetes, was used to study carbohydrate metabolism in rainbow trout, Salmo gairdneri (Richardson). Fish exhibited pronounced and persistent hyperglycaemia on oral glucose administration. Hyperglycaemia was accompanied by decrease in blood amino acids, serum free fatty acids and cholesterol and marked increase in hepatic storage of glycogen. The incidence of oral glucose intolerance results, at least in part from insufficient circulating insulin. Exogenous insulin exerts a hypoglycaemic action and effectively abolishes the hyperglycaemia resulting from glucose administration. Tolbutamidc, the sulphonylurea hypoglycaemic drug, is without effect. Possibly as an indirect result of hyperadreno‐corticism, oral glucose tolerance is markedly improved in the pre‐spawning female. Long‐term feeding of high carbohydrate diet to goldfish Carassius auratus (L.) resulted in gross hepatomegaly due to excessive hepatic glycogen accumulation and, possibly, fatty change of the liver. Protein metabolism was impaired as evidenced by protein depletion. Such degenerative changes in liver metabolism are probably a direct result of oral glucose intolerance and reflect a metabolism adapted to diets normally low in available carbohydrate.
The littoral fauna of Llyn Celyn, North Wales
Authors: Hunt P. C. , Jones J. W.
Published: January 2006

Water level fluctuations of up to 5.5 m in the newly constructed reservoir, Llyn Celyn, were shown to result in a uniformly barren littoral zone in which Lumbriculidae, Pisidium sp. and Chironomidae were the only animals to occur in significant numbers throughout the year. Other groups of animals were unable to survive the big fluctuations in water level and this in turn affected the food and growth of trout in the environment.
The food of brown trout in Llyn Alaw, Anglesey, North Wales
Authors: Hunt P. C. , Jones J. W.
Published: January 2006

The results of the analysis of the contents of 274 brown trout stomachs taken over a period of one year from Llyn Alaw, in Anglesey, North Wales, are described. The annual composition and seasonal changes of the diet were determined using number, volume and occurrence methods. The bottom fauna is classified according to accessibility to the trout as food and the utilization and apparent selection of the fauna by the trout is discussed. Food in relation to trout size is considered in detail.
Growth and annual check formation in scales of dace, Leuciscus leuciscm (L.)
Authors: Mathews C. P. , Williams W. P.
Published: January 2006

The first annual check appears on the scales of Thames dace as the fish begin their third year of life. Counting of annuli does not give the true age of the fish. Data from 4 other habitats are re‐examined and on one occasion it is evident that ageing has been incorrect.
The effect of water level fluctuations on a littoral fauna
Authors: Hunt P. C. , Jones J. W.
Published: January 2006

The littoral fauna of Llyn Tegid, North Wales, in 1968/9 is compared with the results of similar faunal investigations made by Rothwell(née Dunn) in 1951/2 (Dunn, 1953) and Hynes in 1957 and 1959 (Hynes, 1961). The results show the long term effects upon the littoral fauna of the change in mean water level and the increased water level fluctuations produced for a time by the controlled outflow scheme, which came into operation in 1955. In 1961 Hynes recorded big reductions in numbers and variety of invertebrates living in the littoral zone. The reduced water level fluctuations in recent years has resulted in a re‐establishment of some of the fauna.
Ecological aspects of the introduction of fish species into natural habitats in Europe, with special reference to the Netherlands
Authors: Vooren C. M.
Published: January 2006

A total of 39 fish species has been introduced into European waters, mainly during the 19th and 20th centuries: 20 European species (12 successful), 3 Asian species (1 successful), 16 North American species (13 successful). Several successful introductions have produced unexpected and detrimental side‐effects; especially introductions of piscivorous species have created problems. Introductions of the latter type of fishes should be most carefully considered. The aim of fish introductions should preferably be to create temporary populations of non‐reproducing fishes whose numbers can be completely controlled by man.
Some blood parameters of the rainbow trout (Salmo gairdneri Richardson)
Authors: McCarthy D. H. , Stevenson J. P. , Roberts M. S.
Published: January 2006

Fifty rainbow trout of the Kamloops strain were examined for 12 haematological parameters: erythrocyte sedimentation rate, haemoglobin, packed cell volume, erythrocyte count, erythrocyte diameters, mean cell volume, mean cell haemoglobin, mean cell haemoglobin concentration, leukocyte count, differential leukocyte count, plasma total protein and plasma glucose concentration. The fish had been held under known environmental and dietetic conditions, and at the time of sampling were 14 months old. The majority of results for erythrocyte sedimentation rate, haemoglobin, packed cell volume, erythrocyte count, erythrocyte diameters, total protein and differential leukocyte count fell within narrow ranges. The total leukocyte counts and glucose levels were more widely spread. The results are discussed and compared with those already published for Idaho and Shasta strains. It is impossible to say whether the differences that were observed between Kamloops and these other varieties were due to strain alone, since other variables were present. Some problems associated with establishing normal ranges for these parameters in fish are discussed.
Tissue repair in a poikilothermic vertebrate, Carassius auratus (L.): a preliminary study
Authors: Mawdesley‐Thomas L. E. , Bucke D.
Published: January 2006

The effects of mechanical injury on the skin, connective tissue, muscle and bone of the goldfish is described 28 days following the injury. There is evidence of a dynamic response but the apparent inability of muscle regeneration to any degree is noted.
A technique for examining eel otoliths
Authors: Moriarty C.
Published: January 2006

This note describes the use of a rib‐cutting forceps in extracting the otoliths and a method of preparing permanently mounted specimens of burned otoliths.
An experiment on faster growth of salmon Salmo salar (L.) in a Scottish stream
Authors: Egglishaw Henry J. , Shackley P. E.
Published: January 2006

The experiment was made in an attempt to modify the usual relationship in which young trout grow faster than young salmon in streams in which they occur together. A stretch of a trout stream was stocked with advanced salmon eggs, which produced fry earlier than the trout eggs laid naturally. The salmon grew faster than the trout and were longer than the trout at the end of the growing season. The mean length of 77.7 mm attained by the salmon is the largest known size reached by salmon in their first year when feeding on natural food supplies in streams in Scotland. Survival rate from egg planting to production of salmon of this mean length was high.
Plasma oestrogen levels in rainbow trout Salmo gairdneri Richardson
Authors: Schreck Carl B. , Lackey Robert T. , Hopwood M. Lloyd
Published: January 2006

Levels of oestrogens in plasma of mature fall‐spawning rainbow trout Salmo gairdneri were determined using a radio‐immunoassay. No significant difference was found in oestrogen concentration between the sexes (male x̄=2.5 ng/ml; female x̄=4.4 ng/ml); between individual variability was great. Four blood samplings over a 24‐h period via cardiac puncture of males revealed no diel variation or change in estrogen levels due to the stress of bleedings. Although no gonado‐somatic index‐estrogen relationship could be demonstrated for either sex, there was correlation between oestrogen and androgen levels in the female.
A western Scottish population of the leopard‐spotted goby, Thorogobius ephippiatus (Lowe) (Teleostei: Gobioidea)
Authors: Miller P. J. , Rice A. L. , Johnstone A. D. F.
Published: January 2006

A population of the sublittoral leopard‐spotted goby, Thorogobius ephippiatus (Lowe, 1839), is recorded from Upper Loch Torridon, Scotland, and the more northerly occurrence of this Mediterranean‐Atlantic species along western Scottish coasts confirmed. Modified methods of capture are described. Distinctive systematic features of this population, which tends to have low sensory papilla and pectoral ray values, are examined with reference to other T. ephippiatus and the related T. macrolepis (Kolombatovic, 1891). The time of onset and reasons for this local differentiation are discussed.
A preliminary report on the development, growth and survival of laboratory reared larvae of the grey mullet, Mugil cephalus L.
Authors: Kuo Ching‐Ming , Shehadeh Ziad H. , Milken Kathy K.
Published: January 2006

Larvae from artificially bred grey mullet were reared in the laboratory and survival rates of 0.2 %, 5 % and 5 % achieved in three of six trials. Food consisted of wild zooplankton and Anemia nauplii. Feeding began on the fifth day, when the yolk sac was depleted, and intensified on the ninth day. The rate of yolk absorption and feeding intensity were reflected in the growth curve. Larval survival was not affected by withholding food from the larvae till the seventh day from hatching. Two critical periods associated with high larval mortality were apparent on the 2nd–3rd and 8th–11th days after hatching. These were preceded by an increase in specific gravity of larvae followed by passive sinking to the bottom of the rearing tank. Larval length increased from 2.63 mm at hatching to 17.69 mm at the end of the 42‐day larval period. The larvae survived on benthic diatoms therefter. Maximum survival rates were achieved at 22°C. (Oceanic Institute Contribution No. 101).
Parasites of the nine‐spined stickleback Pungitius pungitius (L)
Authors: Dartnall H. J. G.
Published: January 2006

Eleven species of parasite are reported from the nine‐spined stickleback Pungitius pungitius (L). Nine of these, namely, Trichodina domerguei, T. tenuidens, Vorticella sp., Epistylis?, Diplostomum spathaceum, Cryptocotyle lingua, Proteocephalus filicollis, Schistocephalus solidus and glochidia of Anodonta cygnea, are new host records for Great Britain. Gyrodactylus spp. and Thersitina gasterostei were also found.
Changes in the parasite fauna of whiting Odontogadus merlangus L. with age and sex of host, season, and from different areas in the vicinity of the Isle of Man
Authors: Shotter R. A.
Published: January 2006

Infestation of whiting with the helminths Derogenes varicus Müller, Hemiurus communis Odhner, Grillotia erinaceus Van Beneden (plerocercoids) and Contracaecum clavatum Rudolphi, and the copepod Lernaeocera branchialis L., increased with the age of the fish but infestation with the helminths Lecithaster gibbosus Rudolphi, Stephanostomum pristis Looss and Podocotyleatomon and the copepod Clavella uncinata Müller decreased as the fish aged. Infestation with the gill monogenean Diclidophora merlangi Kuhn remained at much the same level in fish 1–5+ years old. Derogenes, Hemiurus, Lecithaster, Cotracaecum and Stephanostomum showed seasonal fluctuations in the levels of their populations in whiting. In all cases the parasites reached a main peak in the summer and early autumn, a time when juvenile digeneans were most apparent.

Whiting from Morecambe Bay were less infested with Clavella than whiting taken from other areas. Experimental evidence suggests that the lower salinity of Morecambe Bay may be responsible; however, this could not account for the lower infestation of Morecambe Bay whiting by Diclidophora which appeared to be unaffected by a lowered salinity. Whiting from the east side of the Isle of Man were more infested with Lernaeocera but less infested with Diclidophora than fish from the west side of the island. The myxosporidian Myxobolus aeglefini Auerbach was externally visible in the sclera of whiting from the east side of the island but absent from the sclera of whiting from the west side of the island. It is, therefore, suggested that whiting to the east of the Isle of Man form a separate sub‐stock from those to the west of the island.
The histopathology of salmon tagging
Authors: Roberts Ronald J. , McQueen A. , Shearer W. M. , Young H.
Published: January 2006

The process of tagging large numbers of juvenile salmon Salmo salar (L.) to enable studies of their migratory pathways, is now well established. A description of the usual method used in Scotland and the immediate pathological effects of the tagging trauma on the young salmon are contained in a previous paper (Roberts et al., 1973). The purpose of the present study was to delineate the long term changes which are apparent in the tag wound at the end of the one or two year period which the majority of salmon spend at sea prior to their return to the native river to spawn.
Movements of salmon Salmo salar (L.) to and from Irish waters
Authors: Went A. E. J.
Published: January 2006

Fish tagged as kelts at a number of Irish stations have been recaptured outside Irish waters along the coasts of Great Britain, Norway and West Greenland. Salmon tagged as smolts in three Irish rivers have been recaptured off the coast of West Greenland and one off the Faroes. Sixteen fish tagged as smolts in Denmark, Great Britain and Sweden were recaptured in Irish rivers or on the coastline of Ireland. Clean salmon tagged in the open sea have travelled to the coasts of Great Britain and a single fish travelled to southern Sweden. Feeding salmon tagged off West Greenland, in the Labrador sea and off the Faroes have been recaptured in Irish waters.
Fecundity of the three‐spined stickleback, Gasterosteus aculeatus (L.)
Authors: Wootton R. J.
Published: January 2006

The number of eggs spawned by female three‐spined sticklebacks Gasterosteus aculeatus (L.) was highly correlated with the size of the fish expressed either as total length or as weight after spawning. There were no significant correlations between the size of the eggs measured either as wet weight per egg or as dry weight per egg, and the size of the fish. Nor were there significant correlations between the calorific value of the eggs and the length or weight of the fish. Regressions relating egg production to the length and the weight of the fish are given. These results and an analysis of previous studies on the fecundity of the stickleback suggest that variations in fecundity are primarily a reflection of variation in the size of the fish at maturity, and that this size is related to the race of the stickleback and to environmental conditions such as food supply which influence the growth of sticklebacks.
The ability of Tilapia mossambica (Peters) to enter deep water
Authors: Caulton M. S. , Hill B. J.
Published: January 2006

Juvenile Tilapia mossambica (Peters) are extremely tolerant of depth and can compensate to a depth increase of 0 to 33 m in a few minutes. As the fish grow they become less able to compensate to deep water. At a total length of 15–18.5 cm small adult male T. mossambica can compensate to 20 m whereas females can only compensate to 13 m. Large adults (20–25 cm) of both sexes compensated to 11.5 m (range 9.5–13 m). Adult fish require 4 to 7 days for maximum depth compensation at 22°C. Analysis of the oxygen content of the swimbladder indicated that this gas accounts for over half the gas in surface equilibrated fish. Oxygen secretion into the swimbladder appears to be the mechanism of equilibration at depth.
Observations on the breeding habits of Clarias gariepinus (Burchell)
Authors: van der Waal B. C. W.
Published: January 2006

Clarias gariepinus (Burchell) can be stimulated to spawn in aquaria by hormonal treatment and the breeding habits could be observed. After pre‐spawning activities such as the raising of dorsal fins and chasing of the female, the male folds around the head of the female and small batches of eggs are laid, followed by some gas bubbles. Eggs are distributed by the female over a wide area. This behaviour agrees with field observations. The final stimulant to spawning under natural conditions is thought to be a substance called petrichor dissolved in flood waters that have run over dry ground.
A pressure chamber for determination of depth tolerance in teleosts
Authors: Hill B. J. , Caulton M. S.
Published: January 2006

The construction and operation of a pressure tank suitable for experimental work on teleosts is described. The tank can be used to simulate depths down to 60 m. The design permits water to flow through the tank at all pressures in order to provide oxygen and remove metabolites but there is no increase in dissolved gases with increased pressure.
Hosts, distribution and pathology of infections with larvae of Eustrongylides (Dioctophymidae, Nematoda) in fishes from East African lakes†
Authors: Paperna I.
Published: January 2006

Eustrongylides sp. larvae were found to be numerous in Bagrus docmac, Clarias mossambicus and Haplochromis spp. from Lake Victoria, rare in Haplochromis spp. and absent from B. docmac and C. lazera from Lake George, East Africa. Larvae encyst in the mesenteries, spleen and in Haplochromis spp. also in the gonads. Unencysted larvae were observed in muscles. Cyst walls consisted of fibroblasts, collagen strands, and were often infiltrated with fat cells. Fatty changes were observed in infected spleens; the muscle tissue, around the unencysted worms, was digested and infiltrated with fibroblasts. Infected gonads, particularly ovaries were deformed and in heavy infections degenerated completely. The biological implication of this infection with larval Eustrongylides sp. on the host populations in Lake Victoria is discussed.
Fish chromosomes: a display by scanning electron microscopy
Authors: Webb C. J.
Published: January 2006

This note reports the first display of fish chromosomes by scanning electron microscopy and assesses the value of this technique to fish karyology.
Toxicity of synthetic detergents to fish and aquatic invertebrates
Authors: Abel P. D.
Published: January 2006

Synthetic detergents are reported to be acutely toxic to fish in concentrations between 0.4 and 40 mg/1. Factors affecting toxicity include the molecular structure of the detergent, water hardness, temperature and dissolved oxygen concentration; the age and species of the test fish, and acclimation to low concentrations of detergent. Some of these factors appear to be of only limited importance. Gill damage is the most obvious acute toxic effect; the immediate cause of death may be asphyxiation, but detergents may also be toxic internally. Lethal effects not related to gill damage have not been investigated. Sublethal effects include retardation of growth, alteration of feeding behaviour and inhibition of chemoreceptor organs. Low levels of detergents may also increase the uptake of other pollutants. Invertebrates, especially in their juvenile stages, are extremely sensitive to detergents: concentrations below 0.1 mg/1 interfere with growth and development in some species. The interactions between detergents and proteins, and their influence on membrane permeability may be the basis of the biological action of detergents. Detergents in natural waters are usually partially degraded, and a maximum permissible concentration of 0.5 mg/1 would probably be harmless under most conditions.
Age, growth, length–weight relationship, sex ratio and food habits of the Argentine pejerrey, Basilichthys bonariensis (Cuv. and Val.), from Lake Peñuelas, Valparaíso, Chile
Authors: Burbidge Richard G. , Carrasco Mario C. , Brown Peter A.
Published: January 2006

Argentine pejerreys were collected in Lake Peñuelas during January 1973. Calculated growth rate was maximum during the 3rd year of life. The length–weight relationship was: log W=‐5.69395+3.25248 log L where W=weight (g), and L=total length (mm). Agegroup I was sexually mature. The sex ratio was 85 males (54%) to 73 females (46%). Young‐of‐the‐year pejerreys fed primarily on copepods, but cladocerans [Bosmina sp. (Baird), Diaphanosoma brachyurum (Liéven), Simocephalus serrulatus (Koch)], ostracods, and dipterans were also represented. Feeding occurred during daylight.
The genetic relationships of the coregonid fishes of Britain and Ireland indicated by electrophoretic analysis of tissue proteins
Authors: Ferguson A.
Published: January 2006

The electrophoretic patterns of the general proteins, esterases, creatine kinase and phosphoglucomutase of white muscle from Lough Neagh pollan, Lough Erne pollan, Lake Bala gwyniad, Loch Lomond powan, Haweswater schelly and Bassenthwaite vendace are consistently of three types. It is therefore suggested that the coregonids examined are three distinct species: the pollans; gwyniad, powan and schelly; vendace. Vendace is genetically closer to the gwyniad group than to the pollans.
Ichthyophthiriasis in the mirror carp Cyprinus carpio (L.) V. Acquired immunity*
Authors: Hines Ron S. , Spira Dan T.
Published: January 2006

Mirror carp (Cyprinus carpio L.) infected with sublethal doses of Ichthyophthirius multifiliis, were free of parasites 21 days after infection. Fish remained free of parasites for at least 8 months when maintained in an infective environment. Such fish were refractory to reinfection with numbers of parasites that killed all normal, previously unexposed fish. Serum from fish recovered from previous infections with sublethal doses of parasites, immobilized free‐swimming stages of I. multifiliis to a dilution of up to 1: 1024. The rise in serum‐immobilization titre occurred between the 10th and 22nd days of infection, the period during which parasites disappeared from the body surface of the fish. Infective stages of the parasite were unable to penetrate the mucus body covering of resistant fish.
The fish populations of an industrial river in South Wales
Authors: Williams R. , Harcup M. F.
Published: January 2006

The River Sirhowy, a trout river of the Ebbw System in south‐east Wales still subject to sporadically high levels of suspended solids derived from the coal mining industry, was investigated over a three year period to assess its importance in the recolonization of a fishless river, the Ebbw Fawr, which is expected to recover from the effects of steelworks effluents discharged near its headwaters. Eight species of fish were recorded. Spawning areas for brown trout (Salmo trutta L.) were limited by industrial and urban developments and the discharge of suspended solids. Small numbers of native trout were produced in the system and the growth of these fish was poor in the main river, confirming the need for regular stocking. Movements of stocked trout were limited except in the lower reaches of the river where the presence of a native population, high levels of suspended solids and flash floods may have increased the numbers of fish moving into the recovering Ebbw Fawr.
Use of lesion filtrates for the transmission of UDN (ulcerative dermal necrosis) in salmonids
Authors: O'Brien D. J.
Published: January 2006

Spawning Atlantic salmon, Salmo salar (L.), brown trout, Salmo trutta (L.) and rainbow trout, Salmo gairdneri (Richardson) were held in tanks for four weeks and then injected with filtrates from lesions of salmon naturally infected with UDN. In some cases prednisolone acetate was included in the inoculum. Water temperatures were recorded daily and the time of appearance of the lesions was noted. Passage experiments using extracts of these lesions were carried out.
Observations on the natural spawning of Alectis indicus (Rüppell) and Caranx ignobilis (Forsk.) (Carangidae)
Authors: von Westernhagen H.
Published: January 2006

Observations on the natural spawning of Alectis indicus (Rüppell) and Caranx ignobilis (Forsk.) were conducted in their natural habitat. Spawning occurred in pairs at daytime between ebbing and flooding tides. The spawning area was a shoal of 35–45 m, located in a deeper channel between two islands. The transparent eggs of C. ignobilis are pelagic.
An electrophoretic method for distinguishing the young fry of salmon Salmo salar (L.) from those of trout Salmo trutta (L.)
Authors: Gardiner W. Ross
Published: January 2006

Young fry of salmon were distinguished from those of trout using electrophoresis of whole fry extracts on cellulose acetate sheets. The separation patterns were revealed by general protein staining. The method was found helpful in resolving the mixed salmon and trout fry of an upland stream.
A checklist of British and Irish freshwater fish parasites with notes on their distribution
Authors: Kennedy C. R.
Published: January 2006

One hundred and sixty eight species of parasite are listed from 36 species of freshwater fish from Britain and Ireland, and notes on their distribution are provided. A list of hosts together with the parasites recorded from them is also given. Although almost twice as many species are listed as in the most recent published reference list, the parasite fauna of Britain appears to be considerably poorer in number of species than that of mainland Europe, and that of Ireland poorer still. The distribution of most species, apart from two endemic species and a very few which have clearly been introduced into Britain in recent years from America or the mainland of Europe, appears to show no peculiarities and is probably contiguous with that of their hosts.
A first north‐eastern Atlantic record of the bluefish Pomatomus saltatrix (L. 1758), (fam. Pomatomidae)
Authors: Cross T. F. , Lyes M. C.
Published: January 2006

The capture of a specimen of the bluefish–Pomatomus saltatrix, (L. 1758) off Ballycotton, Co. Cork, Ireland (Lat. 8°W, Long. 51°50′N) is reported. Some diagnostic features and measurements of the specimen are given. This would appear to be the first record of the species for the Eastern Atlantic, north of Spain.
Histophathology and electron microscopy of channel catfish virus in infected channel catfish, Ictalurus punctatus (Rafinesque)*
Authors: Plumb J. A. , Gaines J. L. , Mora E. C. , Bradley G. G.
Published: January 2006

A histologic and electron microscopic study was made on selected organs from channel catfish Ictalurus punctatus (Rafinesque) fingerlings that were experimentally infected with channel catfish virus (CCV). Histopathology was characterized by necrosis and haemorrhage in kidney and liver, and haemorrhage in the spleen and gastrointestinal tract. Virus replication occurred in nuclei of cells in the kidney, liver and spleen. Intranuclear inclusion bodies consisting of geometric crystalline arrays and lamellar structures were associated with virus replication.
Vertebral abnormalities in common bream Abramis brama (L.)
Authors: Bucke David
Published: January 2006

Vertebral abnormalities in bream Abrama bramis (L.) and lesions of the caudal peduncle are described.
Encapsulated fish hooks from the stomachs of Plectropomus maculatus (Bloch) (Serranidae)
Authors: Walker M. H. , Alexander C. G.
Published: January 2006

Encapsulated fish hooks were found free in the stomachs of Plectropomus maculatus (Bloch). The tissue surrounded only the ferrous part of the hooks which in each case was badly corroded, the brass swivel and plastic sleeve were undamaged. Histological examination showed that the hooks were first surrounded by dense collagen and then by vascularized smooth muscle.
Lymphocystis in wild plaice Pleuronectes platessa (L.), and flounder, Platichthys flesus (L.), in British coastal waters: A histopathological and serological study
Authors: Russell P. H.
Published: January 2006

Wild plaice and flounders with lymphocystis were sampled and their lesion distribution noted. Regression of the lymphocystis cells was seen by histology and a host response including macrophages and immune cells occurred. Antibodies were detectable by a double diffusion precipitin test. The epidemiology is discussed with reference to these findings and to the life histories of the two species.
Film and television in fishery research at Llyn Tegid (Bala Lake), Wales
Authors: Chubb James C. , Jones J. W. , Banks J. W.
Published: January 2006

A 35 mm Robot Royal camera and an electronic flash unit were used at 20–40 m depth in an attempt to identify fish shown on echo‐sounder traces. No photographs were obtained. An 8 mm Eumig automatic electric‐drive cine camera system was used with daylight at 2–8 m depth to test if the equipment served as a deterrent to the fish. Fish were filmed and their behaviour was unaffected by the presence of the equipment. A simple closed‐circuit television system was used with daylight at 0–3 m depth. Low contrast, inherent in the particular equipment, prevented its use at greater depths. Meaningful observations of perch were possible. The use of television camera tubes sensitive to extremely low levels of daylight, and of infra‐red sensitive tubes with an infra‐red light source is briefly discussed. It is concluded that such systems might help to identify problems of netting technique and assist with observations of fish behaviour.
Transmission experiments with pike fry (Esox Indus L.) rhabdovirus
Authors: Bootsma R. , de Kinkelin P. , Le Berre Monique
Published: January 2006

Experimental infection of fertilized pike eggs with ‘red‐disease’ virus produced 100% mortality in the fry. This mortality was associated with a disease that had previously been described as hydrocephalus internus, indicating that ‘red‐disease’ and hydrocephalus are different manifestations of the same disease. The name pike fry rhabdovirus disease (PFRD) is suggested for the disease complex, and the name pike fry rhabdovirus (PFR) for the causative agent. Exposure of PFR to a Wescodyne* solution containing 25 ppm of iodine resulted in an inactivation of at least 99–99% of viral activity within 30 sec. Experimental egg transmission of PFR could be interrupted by disinfecting the eggs in a Wescodyne solution, suggesting that the virus was located on the egg surface. Conclusive evidence of a naturally occurring vertical transmission in pike culture is still lacking because, using FHM cells as a detection system, PFR could not be found in spawners and their sexual products. The susceptibility of pike fry to PFR rapidly decreases at increasing age.
Progress of migrating Atlantic salmon (Salmo salar) along an estuary, observed by ultrasonic tracking
Authors: Stasko Aivars B.
Published: January 2006

Adult Atlantic salmon were captured in the Miramichi esturary, tagged with ultrasonic transmitters, and released. Nine fish were tracked for a total of 425 h, spanning 71 flood and ebb tides. There was drifting with the tidal currents, and holding of position relative to land. Fish that achieved overall upstream progress did so by drifting with flood tidal currents and by stemming the ebb currents. Fish which did not achieve upstream progress also drifted with flood tidal currents, but these fish did not stem the ebb currents and dropped back downstream during ebb tides. No differences in movement patterns were apparent for different times of day or wind conditions.
Selective predation by carp (Cyprinus carpio L.) on benthic molluscs in Skadar Lake, Yugoslavia
Authors: Stein R. A. , Kitchell J. F. , Knežzevic Borivoj
Published: January 2006

Analysis of predation by carp (Cyprinus carpio L.) on mollusc species in Skadar Lake, Yugoslavia, indicated both generalized and specific features of a predator‐prey interaction. Vertical distribution of molluscs in sediments seemed unrelated to predation rates by carp. Although size selective predation may occur, electivity indices appeared most related to shell shape and thickness. Of the three most abundant species, electivity was high for Valvata piscinalis but low for Pyrgula annulata and Dreissencia polymorpha. Valvata has a more readily crushed shell, a higher proportion of occupied shells and a greater percentage of organic content than Pyrgula. Although a potentially preferred prey item, Dreissencia probably escaped intensive predation by being attached to larger objects. Carp appeared to utilize a sequence of tactile and gustatory cues in the prey selection process.
Some observations on the growth and length: weight relationship of the South Georgia cod Notothenia rossii marmorata Fischer during the first four years of life
Authors: Crisp D. T. , Carrick S. M.
Published: January 2006

The paper describes the length: weight relationship and the results of back‐calculating fish length from scale length for Notothenia rossii marmorata Fischer, collected in April 1961 from Leith Harbour, South Georgia.
Seasonal fluctuations in the incidence of epidermal papillomas of the European eel Anguilla anguilla L.
Authors: Peters Gabriele
Published: January 2006

The eels of the Lower Elbe (15–35 cm total length, freshwater age groups III–V) show a high incidence of epidermal papillomas. These neoplasms, situated mainly in the snout region, show a marked seasonal fluctuation. The incidence is low in spring and autumn (min. 2–3 %) and rises sharply in summer (max. 28 %). The size of the papillomas is also smaller during the colder seasons of the year (up to 300 mm3) reaching a maximum in August/ September (up to 900 mm3). The increase in growth of the tumours follows the rise in frequency with a delay of 3–4 weeks. These seasonal fluctuations of tumour growth are possibly related to the alteration of the water temperature and oxygen content.
The helminth parasites of the bullhead Cottus gobio (L.) and the stone loach Noemacheilus barbatulus (L.) from the River Avon, Hampshire
Authors: Rumpus A. E.
Published: January 2006

Specimens of Cottus gobio and Noemacheilus barbatulus from the River Avon, Hampshire, were examined between July 1970 and July 1971. Both fish were found to act as hosts for Nicolla gallica (adult), Pomphorhynchus laevis (adult) and Triaenophorus nodulosus (plerocercoid). The incidence and intensity of infection were lower in N. barbatulus than in C. gobio, and this was related to differences in host diet. A small number of N. barbatulus were also found to harbour Proteocephalus torulosus. Seasonal cycles of incidence and intensity were evident in N. gallica, with a peak occurring in the winter. P. laevis and T. nodulosus showed no such cycles. Increasing host size was associated with a higher infection of both N. gallica and P. laevis, but not T. nodulosus. The diet of the host was considered to be important in influencing this increase. Differences in host reproductive condition affected the population levels of N. gallica only, where an increased parasite burden was evident in gravid female fish. This was considered to influence the observed increase in incidence and intensity of this parasite during the winter. None of the parasites showed any seasonal maturation cycles. There was no evidence of any interactions between the parasite populations. Host diet and the availability of infective larvae were considered to be the most important features influencing the number of parasites which became established, and the rate at which this occurred. Temperature probably acted indirectly on the establishment of N. gallica, by controlling the availability of the larval stages, and also, by influencing the host reproductive condition, on the length of time for which the parasite was retained by the host.
The ability of the cichlid fishes Tilapia rendatti Boulenger, Tilapia sparrmanii A. Smith and Hemihaplochromis (=Pseudocrenilabrus) philander (M. Weber) to enter deep water
Authors: Caulton Mark S.
Published: January 2006

It was shown experimentally that at 22°C, adult Tilapia rendalli can descend to a maximum compensation depth of 8.5 m and that Tilapia sparrmanni penetrate to a maximum depth of 15m. Adult Hemihaplochromis philander males can descend to 16m, and females to 26m at 22°C. At 30°C, the rate at which‐pressure compensation occurred and the maximum depth reached was increased. Fry and juveniles were able to penetrate to greater depths and to descend more rapidly than adults.