bluuebunny/crossref_metadata_2025 huggingface dataset:
Winter‐spring sport fishery in the heated discharge of a nuclear power plant
Authors: Marcy B. C. , Galvin R. C.
Published: January 2006

A substantial winter‐spring sport fishery has developed along the 1.83 km heated discharge canal of a nuclear power plant. An estimated 3166 fishermen caught an estimated 11 090 fish, representing 18 species, during a creel survey conducted from January through June, 1972. Eighty‐seven per cent of the canal fishermen were successful in catching one or more fish, and averaged 2.07 fish per rod‐hour of effort. Fishermen averaged 1.08 fish per rod‐hour and had a 61 % success rate at other areas in the vicinity of the plant from April through November, 1965–1969. There was a correlation between the water temperature of the canal and the number of fish caught per rod‐hour of effort.
A specific ringer solution for the plaice (Pleuronectes platessa L.)
Authors: Cobb J. L. S. , Fox N. C. , Santer R. M.
Published: January 2006

Following analysis of the serum of the blood of the plaice (Pleuronectes platessa L.), a Ringer solution specific for this fish has been devised and tested. It has proved a satisfactory physiological saline for use in electrophysiological experiments and in the preparative procedures for electron microscopy.
The effects of dissolved zinc on the gills of the stickleback Gasterosteus aculeatus (L.)
Authors: Matthiessen P. , Brafield A. E.
Published: January 2006

Concentrations of 0.5–1.0 mg Zn2+/dm3 distilled water killed sticklebacks after 1–3 days, producing detachment and sloughing of epithelial cells, and coalescing of adjacent secondary lamellar epithelia. Cytoplasmic abnormalities included extensive vacuolation, followed by swelling of nuclei and mitochondria leading to cellular disintegration. Many acutely poisoned fish recovered in zinc‐free hard water, regeneration of epithelia being accompanied by a temporary appearance of chloride cells on the secondary lamellae. Concentrations of 2.0–6.0 mg Zn2+/dm3 hard water were not toxic over periods of up to 700 h. Extensive cytoplasmic abnormalities appeared, however, including the formation of membrane‐bounded vesicles and dense accumulations of metabolites. The most pronounced effect was the appearance of active chloride cells on the secondary lamellae. The possible involvement of chroride cells in the excretion of ions other than chloride is briefly discussed.
Aspects of the reproductive biology of the sprat, Sprattus sprattus (L.) in inshore waters of the west coast of Scotland
Authors: de Silva S. S.
Published: January 2006

Aspects of the reproductive biology of the sprat in inshore waters of the west coast of Scotland were investigated from August 1970 to July 1972. Spawning in sprat lasts for a period of five to six months, starting in February‐March. Minimum size of maturity is 88–90 mm in both sexes but males tend to mature earlier in the season. Sprat shed their eggs in 7–10 batches. There is generally a higher proportion of females in the population. The fecundity ranges from 8700 to 46,600 in fish between 95 and 146 mm in length. It is significantly correlated to weight, length and age.
Modification of the response to high density conditions in the guppy, Poecilia reticulata (Peters)
Authors: Warren E. W.
Published: January 2006

An examination was made of some of the factors which influence the response to density in the guppy. Water from high density fish was given to fish populations kept at high and low densities. This induced high density behaviour in low density fish by increasing aggression and decreasing courtship. But giving ‘fresh’ water to high density fish failed to alleviate the response to density. ‘High density water’ slightly reduced the numbers of young found in low density groups. High density fish kept in the dark had more young than high density groups in the light; and the number of young found was decreased when ‘high density water’ was given to low density fish. The number of ovarian stages was decreased in the dark in high density and was not overridden by the type of water. Giving ‘high density water’ to low density fish decreased the number of oocytes stage III, but the interaction between water and ‘light’ was confounded by the total numbers of ovarian stages. Increasing the ‘visual space’ of high density fish with mirrors partially decreased aggression and increased courtship and number of young found; but had little affect upon the number of ovarian stages. Decreasing the number of physical contacts by keeping the fish chronically tranquillized reduced the activity of the fish. This reduced the aggression of the high density fish and also reduced the differences between the high and low density fish on the basis of their courtship scores, number of young found and number of stages in the ovary. Fish from differing population sizes were given a choice between varying fish densities. The fish from a ‘normal’ sized population and with an extended visual field, tended to make a choice conforming to the overall selections compared with fish from populations of extreme size and with a reduced visual field.
The effects of relative density upon some aspects of the behaviour of the guppy—Poecilia reticulata (Peters)
Authors: Warren E. W.
Published: January 2006

Guppy populations were established as one sex or mixed sex groupings, relative degrees of population density were obtained by manipulating the numbers of fish or the volume of the living compartments. Relatively high densities resulted in a reduction in the males courtship behaviour, affecting the number of dorsal fin erections, gonopodial swings, numbers of black spots, number of sigmoid reactions and courtship chases. These measures reached a peak at populations of 12–16 fish/1, falling off both below and above these densities. Associated with a rising fish density was an increase in agonistic behaviour. Activity was not affected by increasing density. Increasing fish density was associated with a drop in the numbers of young fish born and the number of stages occurring within the ovaries. These numbers were greatest at a lower fish density than the behavioural measures.
Observations on the reproductive biology of Mastacembelus armatus (Lacèpede)
Authors: Gupta S.
Published: January 2006

Some observations on the biology of Mastacembelus armatus (Lacepède) from Muzaffarnagar (U.P., India) have been made during the period July 1966 to June 1969. At a particular stage of maturity of the fish there is a close relationship between the gonad weight and the body weight which helps in determining the breeding period of the fish. Both male and female fishes mature simultaneously. The gonad weight influences the relative condition, while the visceral weight does not exert any significant effect on it. The development of the female gonads greatly affect the curve of relative condition, more than the development of male gonads, though the curve for male fish also shows a steady rise and fall in the seasonal variations of the relative condition. Seasonal fluctuations in relative condition correspond to its spawning season. In M. armatus, the presence of two peaks in the curve confirm two breeding seasons. The present studies have also elucidated to a certain extent the important aspect of the maturation and spawning habits of M. armatus in North India. The fish has two breeding seasons of short duration during June and July and again in November. The mature ovaries of each season contain slight maturing ova of next season along with mature ova of the present season. The entire stock of ova measuring 0.16 mm and above are shed during spawning.
Biosociology and ecology of pomacentrid fishes around the Sinai Peninsula (northern Red Sea)
Authors: Fishelson L. , Popper D. , Avidor A.
Published: January 2006

Pomacentrid fishes inhabiting the coral formations along the Red Sea coast of Sinai Peninsula form specific groups of species on various habitats. Amphirion bicinctus, Dascyllus aruanus, D. marginatus and Pomacentrus trichourus are typical for the backreef lagoon; Pomacentrus sulfureus, Abudefduf melanopus and A. melas are common along the rearreef wall; Pomacentrus albicaudatus, P. tripunctatus, Abudefduf lacrymatus, A. leucozona and A. annulatus dominate the coral reef table. The forereef wall is occupied by Abudefduf saxatilis, A. sexfasciatus and A. leucogaster. The lower part of the forereef and coral knolls along it are inhabited by groups of Abudefduf azysron, Chromis dimidiatus, C. caeruleus, C. ternatensis and of the Dascyllus trimaculatus. Among the fishes observed a part are living in groups or schools, whereas others are typical solitary, permanent territory holders. Most of them are polygamous, breeding in colonies, or solitary in nests, guarded by males. The variation in feeding behaviour as well as in sociobiology, enables the high diversity of these fishes on various parts of the habitat.
Estimation of the number of brown trout Salmo trutta (L.) in Loch Leven, Kinross, Scotland
Authors: Thorpe J. E.
Published: January 2006

The numbers of adult trout in Loch Leven were estimated in April each year 1968–71 by tagging fish caught by seine net, and estimating the proportion of the total stock tagged from examination of the angling catch during June‐August. The vulnerability of tagged fish before June and after August was higher than that of untagged fish. Tag losses, estimated by double marking, were 2.15 % over a whole angling season. The reporting rate of tag recaptures varied within and between years from 0.43 to 0.71. Differential mortality of tagged and untagged fish was unimportant, except in two subsidiary experiments when fish were tagged in June and August, when handling losses reached 2.7%. With adjustment for these measured errors, the stock of trout beginning their third or more years in the loch in April, fell from 126 665 in 1968 to 52 337 in 1971.
The movements of brown trout, Salmo trutta (L.) in Loch Leven, Kinross, Scotland
Authors: Thorpe J. E.
Published: January 2006

Juvenile trout enter Loch Leven during autumn and winter from the nursery streams, spend their adolescent phase offshore until reaching a length of 0.30 cm, and then move to the littoral areas in early summer. There are two types of littoral area:‘favourable‘areas from which movement of individual fish in the summer is very restricted, and‘unfavourable‘areas used briefly in early summer from which movement away is pronounced. Trout are absent from the littoral areas in winter. In subsequent summers homing to previous feeding areas is characteristic of fish from‘favourable’areas, with a tendency for older fish to move to the south east area of the loch. Spawning runs occur simultaneously into the main inflows, chiefly between October and December. Emigration into the outflow occurs, but is probably unimportant.
Ligula infestation of bleak Alburnus alburnus (L.) in the tidal Thames
Authors: Harris Martyn T. , Wheeler Alwyne
Published: January 2006

Heavy infestations of the cestode Ligula are reported in bleak Alburnus alburnus (L.) from the tidal Thames. This parasite has not apparently been recorded previously from this host in the British Isles. The life cycle of the parasite is briefly summarized. Data on this infestation suggest an increase in the incidence of infestation up to a maximum in young bleak, followed by a decrease in older fish. There also appears to be a decrease from summer to autumn. The positive relationship between the weight of the parasite and the length of the host is discussed. Observations are made on the effect of Ligula on its host; it is suggested that many of the young bleak die during the autumn and winter, following their infestation.
The effects of environmental stress on outbreaks of infectious diseases of fishes*
Authors: Snieszko S. F.
Published: January 2006

Infectious diseases of fishes occur when susceptible fishes are exposed to virulent pathogens under certain environmental stress conditions. Very little research has been carried out to show the effect of pollution on outbreaks of infectious diseases of fishes. Therefore, examples taken from the literature were selected and reviewed to show the coincidence of infectious diseases with stress caused by temperature, eutrophication, sewage, metabolic products of fishes, industrial pollution, and pesticides.
Specialization in the dentition of the southern graylings—genus Prototroctes (Galaxioidei: Prototroctidae)
Authors: McDowall R. M.
Published: January 2006

The southern hemisphere graylings, Prototroctes oxyrhynchus Günther (1870) (New Zealand) and P. maraena Günther (1864) (Australia) have highly specialized dentition. The alimentary canal is longer than in other salmoniform fishes. These characters, and observations on feeding, suggest that Prototroctes is omnivorous.
Sound production in the cichlid Tilapia mossambica Peters
Authors: Lanzing W. J. R.
Published: January 2006

Aquarium‐bred adult and juvenile Tilapia mossambica Peters can produce sounds ofvarying frequency, duration and intensity. However, minor environmental disturbancesmay cause the fish to fall silent for long periods. The sounds produced by excited feedingfishes are different from those produced by territorial males and from those emitted by fryswimming in school formation. The frequency of the sounds recorded varied from about1–16 kHz; no data are available on frequencies lower than 1 kHz. The sound producingmechanism consists of a single ventral and two dorsal pharyngeals located in the buccalcavity and provided with numerous small teeth. These teeth have a specially modifieddistal surface area which is already evident in younger fish. Young Tilapia, including3‐week old fry, are able to emit sounds as soon as a sufficient number of teeth havedeveloped in the pharyngeal region.
The food and feeding habits of Hydrocynus forskahlii Cuvier and Hydrocynus brevis Günther in Lake Kainji, Nigeria
Authors: Lewis D. S. C.
Published: January 2006

The diets and modes of feeding of Hydrocynus forskahlii Cuvier and Hydrocynus brevis Günther are described. Both species are mainly piscivorous in Lake Kainji. H. forskahlii feeds largely upon small clupeids though very large specimens prey more heavily upon the characid Alestes baremose. H. brevis preys upon a wide variety of species by swallowing them whole but also attacks large fish and bites pieces from them. Sexual dimorphism in H. brevis is described. The effects of predation upon the fish stock of Lake Kainji by Hydrocynus species are discussed.
Ichthyophthiriasis in the mirror carp Cyprinus carpio (L.) IV. Physiological dysfunction*
Authors: Hines Ron S. , Spira Dan T.
Published: January 2006

Changes in blood ion concentration, oxygen absorption, blood haemoglobin concentration and blood urea‐ammonia nitrogen level were measured in a group of mirror carp, Cyprinus carpio (L.) infected with measured numbers of Ichthyophthirius multifiliis under standardized conditions. The disease was characterized by a drop in serum sodium and magnesium and increase in serum potassium. The ability of infected fish to absorb oxygen was reduced as was their ability to tolerate dissolved oxygen concentrations under 5 ppm. Blood ureaammonia level was elevated during the disease but blood haemoglobin level remained unchanged.
The occurrence of ciliary aggregations on the olfactory epithelium of two species of gadoid fish
Authors: Lowe G. A.
Published: January 2006

Ciliary aggregations have been found to occur on the olfactory epithelium of Gadus morhua (L.) and Melanogrammus aeglefinus (L.). The fine structure of ciliary aggregations is constant, consisting of 9 +2 complexes enclosed by a single membrane, though the number of complexes may vary within any ciliary aggregation. It is suggested that ciliary aggregations are motile structures associated with the sensory epithelium and may assist in the circulation of fluid between lamellae.
The influence of water salinity and stage in life history on ion concentration of fish blood serum
Authors: Natochin Yu. V. , Lavrova E. A.
Published: January 2006

(1) The Na, K, Ca, Mg concentration of blood serum have been studied in nearly 60 fish species from various waterbodies (the Neva, Lake Dal'nee, the Volga, Lake Baikal, the White Sea, the Black Sea, the Barents Sea etc.). In fishes (Cyprinidae, Percidae, Siluridae etc.) from fresh water (Lake Dal'nee, the Baikal, the Neva) with low 0.18–0.24 mEq/1 Na concentration Na content in blood serum was lower than in closely related species from fresh water (the Volga, Lyutoga River) with larger Na concentration–nearly 0.5–1 mEq 1. Blood serum of marine teleosts Na concentration (156–210 mEq/1) was higher than in migrating and freshwater species (90–174) mEq/1) and it did not depend on seawater salinity: Barents Sea–465, White Sea–255, Black Sea–227 mEq/1.

(2) Rather a considerable specific variation of ion concentration was found in blood serum of fishes from different families living in the same water body (Lake Baikal: Cyprinidae 90–95 mEq/1, Percidae 114 mEq/1, Salmonidae 126–129 mEq/1 etc.; the Volga: Siluridae 139 mEq/1, Percidae 142–150 mEq/1, Clupeidae 174 mEq/1).

(3) No relation has been detected between K, Ca and Mg concentrations in blood serum of fishes and the concentrations of these ions in the environment.

(4) Na concentration in the blood serum of sockeye salmon juveniles (101 mEq/1) migrating seaward was less than in adult fishes (132 mEq/1) returning to the lake to spawn. Na concentration in the blood of non‐migrating salmonids (Oncorhynchus nerka adult residual 104 mEq/1, Salvelinus alpinus juvenile 140 mEq/1, adult residual 141 mEq/1) changed insig‐ nificantly during life history. Notable hypopotassemia was observed in spawning time in Salmonidae.

(5) The comparison of blood serum ion concentration in males and females of fishes from different taxonomic groups (Acipenseridae, Salmonidae, Cyprinidae) showed no significant variation.
Radiocadmium exchange with seawater by Fundulus heteroclitus (L.) (Pisces: Cyprinodontidae)
Authors: Eisler Ronald
Published: January 2006

Mummichogs, Fundulus heteroclitus (L.) accumulated Cd 115m (NO3)2 from synthetic seawater solutions during a period of 25 days, but the rate of whole body accumulation decreased with increasing concentrations of stable Cd2+ in the medium. Viscera were the major repository of Cd 115m during uptake, especially gastrointestinal tract and to a lesser extent liver. Loss in whole body radioactivity over a post‐treatment interval of 180 days in cadmium‐free seawater was about 90%, with gallbladder and especially liver most influential in the excretion processes; this pattern was unchanged by the level of stable Cd2+ present in the medium during uptake. The significance of this and other observations in terms of field monitoring of cadmium utilizing teleosts as indicators is discussed.
Laboratory studies on food intake, growth and food conversion of young herring, Clupea harengus (L.)
Authors: De Silva S. S. , Balbontin F.
Published: January 2006

Food intake, growth and food conversion of young, O‐group herring were studied at two temperatures and feeding regimes over a period of 19 weeks. The food intake of fish fed to satiation twice daily showed considerable variation. Food intake per fish at 14.5° C was about three times that at 6.5° C, and was generally much higher than in most other species of fish studied. The mean increase in wet weight over the 19‐week period was 0.581 g/week at 14.5° C and 0.236 g/week at 6.5° C in fish fed to satiation and 0.094 g/week at 6.2° C and a ration of 1.3% of the body weight. Growth depensation was found to occur even in fish fed to satiation. The changes in specific growth rate, that is the percentage increase in weight/day, showed similar trends at different temperatures and food regimes. The mean conversion efficiency of fish on a ration of 1.3% at 6.2° C was higher than that of fish fed until satiation, at 14.5 and 6.5° C. The conversion efficiency of fish fed to satiation at 14.5° C showed a distinct decrease with increasing weight while at 6.5° C such a clear trend was not observed. In general, the conversion efficiency of young herring were found to be much lower than that of most other species studied. The weight exponent of the quantitative relationship between food intake and body weight at 14.5° C was 0.744. The total metabolic expenditure at 14.5° C, calculated using Winberg's (1956) ‘utilization coefficient, gave a weight exponent of 0.773.
Dermocystidiosis–a gill disease of the carp due to Dermocystidium cyprini n.sp.
Authors: ČErvinka S. , Vítovec J. , Lom J. , Hoška J. , Kubů F.
Published: January 2006

A new species of Dermocystidium is reported to be the causative agent of three outbreaks of gill disease in carp observed in recent years in Czechoslovakia. No other parasites or influences could be held responsible for the disease. It is suggested that at least some of gill disease of unknown aetiology in carp is due to dermocystidia, and the disease might be distributed in many regions of Europe. A description of a greater part of the developmental cycle of the species D. cyprini n.sp. Červinka et Lom, is presented, supplemented by a discussion of other species of the genus. A summary of known facts on the host‐parasite relation in these parasites is also given.
The upstream migratory behaviour of salmonids in the River Frome, Dorset
Authors: Hellawell J. M. , Leatham H. , Williams G. I.
Published: January 2006

Data on the migratory behaviour of salmonids were collected at a gauging weir by means of a restivity fish‐counter which triggered a motor‐driven 35 mm still camera to provide photographic records of passing fish. A clear bimodal seasonal pattern of movement was observed in three consecutive years with peaks during June–August and October–December. Daily variations in the rate of movement could not be correlated with changes in discharge or temperature. Salmonids tended to move at discharges lower than those generally available. This contrasts with other published work and was attributed to the more equitable flow‐pattern of chalk rivers. There was no optimal temperature associated with movements. Some evidence suggested that the largest fish moved earlier in the year but this was not marked. In clear water most movement occurred during the hours of darkness but during floods, when the river was turbid, the diurnal pattern tended to be reversed with greatest movement during the hours of daylight. Most fish negotiated the weir close to the bottom, well below mean velocity, and took a central path through the flume. Although analysis of upstream migratory behaviour was hindered by the lack of data on the numbers of fish available below the counting point it was concluded that the basic pattern of migration is established by time (season). Changes in discharge, light intensity and other parameters may then play a secondary role in modifying the details of the pattern but attention is drawn to records of movements in regulated flows where a remarkably constant pattern is shown from year to year.
Changes in haematocrit values in blood samples treated with and without oxygen: a comparative study with four salmonid species
Authors: Soivio Antti , Westman Kai , Nyholm Keijo
Published: January 2006

Changes in haematocrit values under lowered oxygen tension and aerobically treated blood samples of rainbow trout Salmo gairdneri (Richardson), landlocked Baltic salmon S. salar (L.), brown trout S. trutta lacustris (L.) and lake trout Salvelinus namaycush (Walbaum) have been studied in vitro. The mean haematocrit value increased during 2 h incubation under lowered oxygen tension by 32.7 ± 3.1% in rainbow trout, 28.2 ± 2.8% in landlocked Baltic salmon, 29.2 ± 5.6% in brown trout and 25.2 ± 2.8% in lake trout. During corresponding incubation with oxygen the mean haematocrit value decreased below the starting level by 18.1 ± 1.9% in rainbow trout, 18.3 ± 4.8% in landlocked Baltic salmon, 22.4 ± 0.7% in brown trout and 11.8 ± 1.7% in lake trout. Consequently, the changes in the haematocrit values were greater in the species belonging to the genus Salmo than in that of the genus Salvelinus. The increase in the haematocrit values seems to have resulted from swelling of the erythrocytes and their decrease is similarly attributable to shrinking of the cells. The reasons for this swelling, which may be complicated, and its apparent significance for haematocrit determinations are discussed.
Production biology of the upland bully Philypnodon breviceps Stokell in a small New Zealand lake
Authors: Staples D. J.
Published: January 2006

Estimates of production, food consumption and efficiency of food utilization for a population of the upland bully, Philypnodon breviceps Stokell, in Small Spectacles (the smaller of two lakes known as Spectacles Lakes) are given for the period February 1969 to March 1970. Length: weight relations were similar among age groups within any one month but a seasonal variation in the ‘condition’ offish, as well as in calorific content of body tissue, was recorded. The mean population biomass was estimated as 21.98 g/m2 (21.85 kcal/m2) over the study period; maximum biomass of younger age groups occurred during the late summer but little seasonal change occurred in older groups. Total annual production was 39.78 ±8.25 g/m2 (39.55 kcal/m2), but this estimate did not include any fish in their first 1.5 months of life because of the lack of recruitment during the 1969 breeding season. Approximately 70% of production occurred during three months in late spring and summer, and 97% resulted from the two youngest age groups. In fish over one year old, male production doubled that of females, a difference which could be attributed to the greater number and faster growth of male fish. Production due to sexual products amounted to less than 1% of the total production. Annual food consumption was approximately 302.8 g/m2 (249.7 kcal/m2) and the gross efficiency of food utilization was in the order of 16%. Efficiency was similar between sexes of the same age group; faster growth and production of males, therefore, resulted from a greater food consumption rather than a difference in utilization of food. Efficiency was highest during spring and summer and, for most of the year, decreased with age. Efficiency was low in autumn when, although food consumption was relatively high, little production resulted. These seasonal and age differences are discussed with respect to Paloheimo & Dickie'sK‐line model.
Some observations on the ecology of Galeus piperatus Springer and Wagner, a little known shark endemic to the Northern Gulf of California*
Authors: Mathews C.P.
Published: January 2006

Galeus piperatus Springer & Wagner, the peppered shark, is a dwarf shark found in the Gulf of California north of the City of Guaymas, Sonora. It has been taken in June and August 1971 and in February and March 1972, and is found from 130–550 m with maximum abundances from 170–420 m deep. Numbers are higher in June and August (up to 110 individuals/ha) than in February and March. In June and August 1971 the area of distribution included all the waters north of Isla Tiburón and Isla Angel de la Guarda, and below the 130 m isobath. During these months Galeus piperatus was found at 12 and 33 stations respectively, but was taken at only one station in the same area during February and March 1972. The fishing effort expended during these periods was 16, 42 and 60 units respectively. It seems likely that a strong migratory movement causes these differences in abundance and distribution. Galeus piperatus has been taken from 50–100 m off the bottom in mid‐water trawls at night and is clearly a mid‐water and demersal form. Sexually mature females carrying olive green egg cases were taken in large numbers in June 1971 and were also present in reduced numbers in August 1971. Only females 18 cm or more in total length carried egg cases. The migration of Galeus piperatus into the North Gulf of California appears to coincide with sexual maturity.
Individual differences in response to an open field test by the guppy—Poecilia reticulata (Peters)
Authors: Warren E. W. , Callaghan Shirley
Published: January 2006

Guppies Poecilia reticulata (Peters) were subjected to repeated measures of 5 min duration, on an open field test. The major measures were the number of times a fish changed sections, the number of different sections entered regardless of how many times they entered a section and the ratio of inner to outer sections entered. The activity scores were on a continuous distribution from fish to fish and for the males correlated highly with the ratio of inner to outer movements, but not so for the females. All fish showed a preference for the outer rings compared to the inner rings. There was a non–significant tendency for the male activity to increase during each test, but to wane as the number of tests increased. The females showed a variation of activity which may be associated with their ovarian cycle, but the various activity measures tended not to correlate with each other during the cycle and also failed to correlate with various published cycles of physiological ovarian activity.
Reproductive biology of anadromous arctic char, Salvelinus alpinus (L.)? in the Cumberland Sound area of Baffin Island
Authors: Moore J. W.
Published: January 2006

The ovaries of anadromous arctic char, Salvelinus alpinus (L.), captured during 1973 from four high arctic rivers on Baffin Island started to increase in weight early in July and were at their heaviest in mid‐September just before spawning. At this time, 40 cm (615 g) char from two rivers contained ovaries weighing 17.0 g (dry) which differed significantly from the 22.5 g gonads of comparable char from the other two areas. Gonadal development in male fish began in June and the diameter of testes at full maturity (3.0–4.0 cm) was similar regardless of river system. Fecundity of comparable fish varied significantly among the rivers with char 40 cm in length containing 1400–2400 eggs while the corresponding values for 60 cm (i.e. 2050 g) char ranged from 4000–5500. The diameter of both immature and mature eggs was similar regardless of system. Values for immature eggs averaged 0.64 mm in 40 cm fish and 1.60 mm in 60 cm specimens. Diameter of mature eggs, on the other hand, was considerably greater (3.2 and 4.3 mm, respectively). Maturity was first reached at age 10 (i.e. 35 cm) in both males and females and maturing fish of both sexes were not always restricted to fresh water. Redd construction occurred at a depth of one to at least 11 m at a temperature of 0.5–4.0° C. The percentage of eggs retained in the body cavity after spawning varied from 0.22–1.50 and the mortality rate of spawned eggs was extremely low.
Rare and little‐known fishes in British seas in 1970 and 1971
Authors: Wheeler Alwyne , Blacker R. W. , Pirie S. F.
Published: January 2006

Records of occurrence of species of interesting, little‐known, or rare fishes in British seas for the years 1970 and 1971 are given. The significance of these records is discussed briefly in some cases.
Aquarium studies on the selectivity of 16 aquatic plants as food by fingerling hybrids of the cross between Ctenopharyngodon idella ♂ and Cyprinus carpio ♀
Authors: Duthu Gwen S. , Kilgen Ronald H.
Published: January 2006

Fish hybrids of the cross Ctenopharyngodon idella♂ (grass carp) and Cyprinus carpio♀ (Israeli carp), averaging 124 mm total length and 20 g in weight were stocked in aquaria along with 16 different aquatic plants to determine which plants they would eat. Observations showed that one group of plants was highly utilized (Azolla caroliniana, Lemna spp., Cladophora sp., Spirogyra sp., Nymphaea odorata); another group was moderately utilized (Pistia stratiotes, Ruppia maritima, Najas flexilis, Limnobium spongia, Potamogeton pecti‐natus). Two other groups were only poorly utilized (Ceratophyllum demersum, Eichhornia crassipes, Elodea sp.), or not utilized (Cabomba caroliniana, Sigittaria sp., Myriophyllum pinnatum).
Some blood parameters of the rainbow trout (Salmo gairdneri Richardson)
Authors: McCarthy D. H. , Stevenson J. P. , Roberts M. S.
Published: January 2006

Some of the blood constituents of male, female and immature rainbow trout of the Shasta variety, maintained in known environmental and dietetic conditions, were examined and the results statistically treated. The parameters for male and female trout were similar, only the erythrocyte count exhibiting a significant difference. Large but expected differences were evident between the parameters for mature and immature fish.
The effect of temperature on the ability of Tilapia mossambica Peters to enter deep water
Authors: Caulton M. S. , Hill B. J.
Published: January 2006

The ability of adult Tilapia mossambica Peters to enter deep water was determined at 15, 22 and 30°C. At 30°C adults compensate to about 20m depth but at 15°C to only 7 m. Compensation is more rapid at high than at low temperatures. T. mossambica haemoglobin has a marked Root effect which is the same at 22 and 30°C. The oxygen affinity of the haemoglobin is higher at 15°C than at 30°C. There was no measurable difference in the rate of passive oxygen diffusion across the swimbladder wall in the temperature range 15–30°C. It is concluded that the ability to enter deeper water at higher temperatures is related to decreased oxygen affinity of the haemoglobin and higher rates of oxygen secretion and blood circulation.
Aspects of the ecology and life history of the sculpin, Coitus aleuticm(Gilbert), in Lake Washington
Authors: Ikusemiju Kola
Published: January 2006

Aspects of the ecology and life history of the sculpin, Cottus aleuticus (Gilbert) were investigated. The fish exhibited a diurnal vertical migration towards the surface at night and towards the bottom during the day. It grew to a total length of 54 mm and attained this size at an age of about two years. The growth pattern was the same irrespective of season. It fed mainly on ostracods and chironomid larvae. Fecundity varied from 114–298 eggs.
Some aspects of the biology of the cercaria and metacercaria of Stephanostomum baccatum (Nicoll, 1907) Manter, 1934 (Digenea: Acanthocolpidae)
Authors: MacKenzie K. , Liversidge Janet M.
Published: January 2006

Experimental proof is presented that Cercaria neptunae Lebour is the cercaria of Stephanostomum baccatum and that the gastropods Buccinum undatum (L.) and Neptunea antiqua (L.) both act as its first intermediate hosts in the north‐east Atlantic. Heavy experimental infections were associated with mortalities of 0+plaice Pleuronectes platessa (L.). The probable effects on plaice of infections at intensities below the lethal level are discussed. Under natural conditions almost all S. baccatum infection of plaice occurs in the first year of life, but newly emerged cercariae were shown experimentally to be capable of encysting in the musculature of plaice up to three years old. The thicker epidermis of older plaice may account for their resistance to infection. Common dabs were more easily infected than plaice. The ability of S. baccatum cercariae to infect plaice and common dabs is inversely related to the length of time between emergence and contact with the host. The differences in skin structure between opposite sides of the plaice body may account for the asymmetrical distribution of metacercariae in the musculature. The potential use of S. baccatum as a biological tag is discussed.
Fish chromosome techniques–a review of selected literature
Authors: Blaxhall P. C.
Published: January 2006

This is a review of some of the literature on the use of chromosome techniques with fish. There is a need for developing methods which leave the animal alive. Such a test is the leukocyte culture method used in human medicine. Once a reliable test has been developed the results should show more consistent karyotypes and better morphology thus providing information of use in cytotaxonomy, fish‐breeding and in studying the effects of sub‐lethal levels of water pollutants on fish.
Studies on the swimming musculature of the rainbow trout I. Fibre types
Authors: Johnston I. A. , Ward P. S. , Goldspink G.
Published: January 2006

A histochemical study has been made on the myotomal musculature of the rainbow trout Salmo gairdneri Richardson. Four main types of fibre can be distinguished on the basis of differences in fibre size, lipid content and succinic dehydrogenase and myofibrillar adenosine triphosphatase activity (ATPase activity). Early histological studies have concluded that in addition to a superficial strip of muscle small diameter ‘red’ fibres occur throughout the trout myotome. These small diameter fibres occurring in the bulk of the myotome are shown to differ from the superficial fibres with respect to their oxidative metabolism and myofibrillar ATPase. The relevance of this finding to studies on the energetics and swimming efficiency of this species are discussed.
Biology of the radiated shanny Ulvaria subbifurcata Storer in Newfoundland (Pisces: Stichaeidae)
Authors: LeDrew Bevin R. , Green John M.
Published: January 2006

Ulvaria subbifurcata is found on the north‐east Atlantic coast of North America. Fish less than 55 mm preyed predominantly on copepods, while larger ones ate mainly nereids; polynoids and amphipods were eaten by all sizes. These four food items comprised the main food of the radiated shanny. Spawning occurred in May with the fish first spawning at age three to five. No conspicuous secondary sexual characters were observed. Females spawned once per year, producing a demersal egg mass. Males spawned up to four times and tended the egg mass (or masses). Incubation lasted 35–40 days, and the pelagic larvae settles on the bottom by August. Adult males tended to be larger than females of the same age but little difference was found sexually in the length–weight relationships. Ulvaria subbifurcata larger than 60 mm are nocturnal. This may reduce predation by, and competition with, other inshore benthic fishes.
Interaction of odour and flow perception and the effects of parathion in the locomotor orientation of the goldfish Carassius auratus L.
Authors: Rand G. , Kleerekoper H. , Matis J.
Published: January 2006

The effects were studied of a 24 h exposure to a subacute concentration of parathion (0.33 p.p.m., which is approximately equivalent to 0.5 of the 48‐h LC50) on the locomotor orientation of mature goldfish Carassius auratus L., 26–30 cm long, in response to a food odour and a water flow differential, singly and in combination, in a free choice situation. Prior to exposure, food odour alone was significantly attractive but the combination ‘food odour with increased water flow’, as compared with the control situation, was avoided. Factorial analysis demonstrated interaction between odour and increased flow. After exposure to parathion the food odour ceased to be attractive and was significantly avoided. This avoidance was not present in the ‘food odour‐increased flow’ combination. The parathion exposure did not affect the response to the flow conditions per se but reversed the interaction between food odour and increased flow. In addition, the exposure to the pesticide itself, in a second order interaction, interacted with ‘food odour‐flow’ response. Hence, the short term exposure to the subacute organophosphate concentration affected not only the perception of food odour and flow individually, but also the interaction between these common environmental stimuli.
Studies on the toxicity of zinc sulphate and of cadmium sulphate to stone loach Noemacheilus barbatulus (L.) in hard water
Authors: De L. G. Solbé J. F. , Flook Valerie A.
Published: January 2006

The toxicity of zinc sulphate and cadmium sulphate to stone loach Noemacheilus barbatulus was examined in an attempt to explain the distribution of the species in two polluted streams. Stone loach in hard water were more sensitive than rainbow trout to zinc, but much more resistant to cadmium. Their disappearance from the Willow Brook, Northants, in 1971–72 could be accounted for by zinc toxicity. A behavioural change, the loss of the instinct to hide during daylight, occurred in subsequently lethal concentrations of cadmium. The accumulation of cadmium in several tissues was also determined.
Tripterygion atlanticus sp. nov. (Teleostei–Tripterygiidae) the first record of a tripterygiid fish in North‐Western Europe
Authors: Wheeler Alwyne , Dunne James
Published: January 2006

A northward extension of the range of the family Tripterygiidae is reported. Several specimens have been captured in the vicinity of Roscoff, North Finisterrc on the coast of Britanny, and presumed sight records from the English coast of the English Channel are reported. These specimens differ sufficiently from the four recognized European species to be regarded as taxonomically distinct. The name Tripterygion atlanticus is proposed for this species which is formally described.
Age and growth of the catfish Bagrus meridionalis Gunther in southern Lake Malawi
Authors: Tweddle D.
Published: January 2006

Vertebrae from 250 Bagrus meridionalis from the southern end of Lake Malawi were used for age and growth determinations. There is a close correlation between ages determined from length frequency data and ages obtained by back‐calculation of the lengths when vertebral rings arc laid down. The rings are laid down annually, probably during the breeding season. Females grow slightly faster than males, the difference being in the order of 1–2 cm/year in the early stages. Recruitment to the trawl fishery takes place in the third year of life. Both sexes breed for the first time at the end of their fourth year. There is a much greater mortality in the male population after 40 cm in length.
A redescription of Pomatoschistm norvegicus (Collett, 1903) (Teleostei: Gobioidei) based on syntype material
Authors: Webb C. J. , Miller P. J.
Published: January 2006

A deeper water species of the Mediterranean‐Atlantic gobiid genus Pomatoschistus, P. norvegicus (Collett, 1903), is redescribed from syntype material, including details of the lateral‐line system and a summary of geographical distribution. The systematic status of P. norvegicus is briefly discussed with reference to the other nominal species, P. minutus (Pallas) and P. lozanoi (De Buen), of the ‘P. minutus’ complex.
Studies on grayling, Thymallus thymallus L., in Llyn Tegid and the upper River Dee, North Wales.
Authors: Woolland J. V. , Jones J. W.
Published: January 2006

Scale and length/weight data from 2071 Llyn Tegid grayling and 1803 River Dee grayling were used for age and growth determinations. The time of scale annulus formation varied from autumn in some years to spring in other years. Seasonal changes in length, weight and the condition factor were described. The main growth period was from spring to autumn with very little growth occurring during the winter. Annual growth in length was back‐calculated from scale measurements, and von Bertalanffy's model was fitted to the resulting length for age data. Comparisons were made between the specific growth rates and ultimate lengths (Lx) of Llyn Tegid and River Dee grayling, and between the growth of male and female grayling. Males grew faster than females after the onset of sexual maturity. Calculated lengths were converted to weights using a combined length/weight relationship for Llyn Tegid and River Dec grayling. Changes were evident in this relationship throughout the life of the fish.
The eels of Lake Kariba: distribution, taxonomic status, age, growth and density
Authors: Balon Eugene K.
Published: January 2006

It had been predicted that eels would disappear from Lake Kariba because juveniles would be unable to surmount the dam which was closed in 1958. This prediction has been proved wrong. In 1970–71 an abundant population of eels was discovered in the lake, mostly at depths from 25–40 m. The eels have intermingled characters of both the mottled Anguilla nebulosa labiata and the plain‐colored A. mossambica. A clear separation of these two taxa was impossible and therefore conspeciflc status of these two species is suspected; the name A. n. labiata is retained for the population.

The age structure of the eel cohorts suggests that juveniles surmount the dam in their second year of life and then spend approximately 7 years in streams of the lake drainage. The fastest maturing individuals which are in best condition then emigrate to the ocean, whereas the slower maturing eels remain in the lake longer. The oldest eel in the samples was 18 years old.

The catch per unit of effort for hoopnets was 2.35 kg in the upper part of the lake and 0.41 kg for the lower part of the lake. The density at Namazambwe was assessed at 46 eels per 1 ha. The unexploited eel population of Lake Kariba could form a valuable resource.
Blood and liver enzymes in rainbow trout (Salmo gairdneri Rich.) with emphasis on their diagnostic use: Study of CCl4 toxicity and a case of Aeromonas infection
Authors: Racicot J. G. , Gaudet M. , Leray C.
Published: January 2006

The effect of one intraperitoneal injection of 1.33 ml of CCl4 per kg of fish was studied. Two experimental series were performed and studied for 10 days (with diluent) and 24 h (pure CCl4) periods. LDH, GOT, GPT, GR, GDH, CPK, G‐6‐Pase, and AlkPase were studied. The activity of all enzymes in blood increased: LDH (four times the control), GOT (two times), GPT (three times); they reached a maximal activity 12 h after injection of diluted CCl4. The levels of some enzymes were also examined in the liver. With pure CCl4, maximal enzyme activity in blood occurred earlier (6 h). A 6 to 10 times increase was observed for GOT, GPT, LDH, GR, and GDH. Histopathological observations were correlated with these enzymes studies.

An Aeromonas disease characterized by the destruction of the dermis, the exposure of the muscle, and by the presence of numerous petechiae in the liver enabled us to examine the relationships between naturally induced tissue damage and enzyme levels in blood. The levels of seven blood enzymes were determined and the most significant modifications were observed for LDH and CPK. which increased their concentration from 3 to 7 times respectively. A pyruvate saturation test demonstrated that LDH was probably from liver as it was observed after CCl4 poisoning. The contribution of such biochemical studies in fish research is evaluated.
Effects of hyperbaric pressure on oxygen concentration in the swim bladder of Poecilia latipinna.
Authors: Ross Sterhen
Published: January 2006

Poecilia latipinna was subjected to varying hydrostatic pressures in the laboratory which demonstrated the following points. The hyperbaric chamber is a suitable apparatus for testing gas gland secretion in this teleostean fish. Oxygen concentration within the swim bladder increased with increasing hydrostatic pressure. Pressures encountered by fishes at various levels of the water column and their effects on oxygen concentration in the swim bladder may be simulated in the laboratory.
A comparison of growth and abundance for tidal pool fishes in California and British Columbia
Authors: Michael E. , Chadwick P.
Published: January 2006

A qualitative comparison of species compositions, relative abundances, diversity and growth was made between tidal pool fishes collected in Port Renfrew, British Columbia and Bruels Point, California. The two most preponderant cottid species Oligocottus maculosus and Clinocottus globiceps were aged using vertebrae, from which back calculated growth values were obtained. Species from Port Renfrew were found to have a higher diversity index, greater species composition and abundance. No growth differences were found between the two localities despite the 1120 km (700 miles) separating then.
The existence of two races of Atlantic salmon (Salmo salar L.) in the British Isles
Authors: Child A. R. , Burnell Ann M. , Wilkins N. P.
Published: January 2006

Sera from approximately 10 000 Atlantic salmon collected from rivers in the British Isles have been analysed. Polymorphism at the transferrin locus was observed and the distribution of the transferrin alleles provides further evidence supporting the presence of two races of salmon first postulated by Payne et al. (1971a).