bluuebunny/crossref_metadata_2025 huggingface dataset:
The accumulation of radioactive caesium from food by the plaice (Pleuronectes platessa) and the brown trout (Salmo trutta)
Authors: Hewett C. J. , Jefferies D. F.
Published: January 2006

The patterns of accumulation of caesium‐137 from food by the tissues and organs of a marine teleost, the plaice (Pleuronectes platessa) and a freshwater teleost, the brown trout (Salmo trutta) are described and compared. Estimates of the biological half‐times and steady‐state concentrations are derived and individual organ intakes calculated. Rate constants are similar to those obtained from the accumulation from water studies. Plaice gut and liver have an 11 % increase and trout gut a 6 % increase in their share of the [137Cs] intake arising from accumulation from food, compared with that arising from the accumulation from water. These increases were balanced by decreases in the muscle share of the intake. The overall absorption of [137Cs] from food was 42% for plaice and 67% for trout.
Metazoan arasites of fish from the Smallwood Reservoir, Labrador, Canada
Authors: Chinniah V. C. , Threlfall William
Published: January 2006

Three‐hundred and thirty‐two fish of eight species (5 Salmo salar, 68 Salvelinus fontinalis, 32 S. namaycush, 102 Coregonus clupeaformis, 1 Prosopium cylindraceum, 107 Esox lucius, 14 Catostomus catostomus, 3 Couesius plumbeus) from the Smallwood Reservoir, Labrador, Canada, were examined for metazoan parasites, using conventional parasitological techniques.

Fifteen genera of parasites were recovered (two of Monogenea, two of Digenea, four of Cestoda, three of Nematoda, two of Acanthocephala and two of Copepoda), these including seven new host records.

Significant differences were noted in the prevalence of the various parasites which were common to the different species of fish examined. No differences were recorded in the parasite burden of male and female fish. There was no correlation between the number of parasite species per infected fish and host age except in the case of Salvelinus namaycush. Food items of the fish examined were also noted.
Studies on the chemical biology of young grey mullet, Mugil cephalus L.
Authors: Perera P. A. B. , De Silva S. S.
Published: January 2006

The chemical composition of tank and pond reared and wild young grey mullet, Mugil cephalus L., ranging in length from 15 to 75 mm was studied. Tank reared mullet had a higher percentage of protein, carbohydrate, total lipid and a lower moisture content than wild fish. These differences are attributed to the artificial diet, available in excess, as well as the relatively inactive life in the confined spaces of the rearing tanks. M. cephalus in general has a high percentage of total lipid and therefore, can be classified as a ‘fatty’ fish. The highest level of protein in tank reared fish was found in those kept at a salinity of 20‰. Fish reared on an excess diet in fresh water tended to show a close similarity to wild fish in trends of change of chemical constituents with growth.
The reproductive biology of the dab Limanda limanda (L.) in the North Sea: Seasonal changes in the testis
Authors: Htun‐Han M.
Published: January 2006

Spermatogenesis in the dab is described in five easily identifiable stages: spermatogonium (Stage I), primary spermatocyte (II), secondary spermatocyte (III), spermatid (IV), and spermatozoon (V). The annual reproductive cycle in male dab may be divided into four morphologically and histologically distinct periods: prespawning (September‐November), spawning (December‐March), postspawning (April‐May) and resting (June‐August) period.
The effects of polychlorinated biphenyls on plasma steroid levels and hepatic microsomal enzymes in fish
Authors: Sivarajah K. , Franklin C. S. , Williams W. P.
Published: January 2006

Aroclor 1254 was administered intraperitoneally (25 mg kg body wt−1 in 1 ml of arachis oil) at weekly intervals for 4 weeks to trout and carp; arachis oil was used as the control. Activities of the following hepatic microsomal enzymes, aminopyrine demethylase, p‐nitroreductase, UDP‐glucuronyl‐transferase and 1‐leucyl‐β‐naphthylamide splitting enzyme were measured in both species; cytochrome P450 and microsomal protein contents were also determined.

The changes in the levels of androgens, oestrogens and corticoid hormones were measured in the circulating blood of control and treated groups at weekly intervals. The blood was obtained by cardiac puncture.

Results indicated (a) a significant increase in the activities of all the enzymes measured except 1‐leucyl‐β‐naphthylamide splitting enzyme, (b) cytochrome P450 and microsomal protein contents were increased in trout, but not in carp, (c) a significant reduction in the plasma levels of androgens, oestrogens and corticoids in the treated groups, particularly at the end of the fourth week and (d) there was a correlation between increased enzyme activities and a decrease in plasma hormone levels.
Changes in body composition associated with smoltification and premature transfer to seawater in Coho salmon (Oncorhynchus kisutch) and King salmon (O. tschawytscha)
Authors: Woo N. Y. S. , Bern H. A. , Nishioka R. S.
Published: January 2006

Serum protein, glucose and fat levels were determined for Coho salmon parrs, freshwater smolts, seawater smolts, seawater stunts and freshwater desmolts. Liver and muscle glycogen, fat, protein and water concentrations were also calculated. Serum protein, glucose and fat levels were significantly lower in the freshwater smolts than in the parrs. Furthermore, both liver and muscle total fat levels were markedly decreased in the smolts, suggesting that smoltification is associated with increased catabolism. Smolts that failed to reach seawater by late summer reverted to a parr‐like appearance and also regained the biochemical characteristics of parrs (high body fat and glycogen). Premature transfer of Coho presmolts into seawater caused impaired growth (stunting). Stunted Coho had higher muscle protein levels than normal smolts and parrs. Tissue water levels were not significantly different between stunts and normal seawater smolts, suggesting that the stunting phenomenon may not be caused primarily by osmoregulatory failure but may be due to shifts in metabolic patterns. In contrast to the pronounced changes seen in Coho salmon, transfer of King salmon to sea water did not result in increased catabolism of body reserves or in the production of stunts.
A note on the dispersion pattern of marked bream Abramis brama released into Tjeukemeer, The Netherlands
Authors: Goldspink C. R.
Published: January 2006

Following the release of 4619 opercular tagged bream in Tjeukemeer, 101 fish were subsequently recaptured outside the lake (1969–72). The maximum distance travelled was 60 km. Although the initial dispersal of fish out of the lake appeared to be random there was some evidence of homing once fish had gained access to the IJsselmeer.
The population density, growth rate and production of bream, Abramis brama, in Tjeukemeer, the Netherlands
Authors: Goldspink C. R.
Published: January 2006

A method of estimating the population density of bream in Tjeukemeer (21.3 km2) using 16 690 introduced fish (fin‐clipped and opercular tagged) is described. Gill nets of the winter fishery proved to be a more effective method of sampling the population for marked fish than fyke nets. The population density of bream (⋝25 cm) was estimated to be 180 000. There was no significant difference between the estimates derived from fin‐clipped and opercular tagged fish. The growth rate of bream in Tjeukemeer (L∞=41 cm) is poor compared with that of bream in other waters, due to its high density and the scarcity of zoobenthos available to it.

The production of bream (I–XV) is estimated to be 34 kg ha−1 of which 25% is contributed by two (1959, 1963) strong year classes. Of a total biomass of 37.5 kg ha−1 available to the fishery in 1969 only 2.7 kg ha−l was removed as yield. The average P/B ratio for the population was low (0.39). It is concluded that a major flow of energy to bream is through zooplankton.
Studies on the growth of juveniles of Cynoscion striatus in the sea and in aquaria
Authors: de Ciechomski J. D. , Cassia M. C.
Published: January 2006

This paper reports on the studies on growth of juveniles, 20–140 mm in length, of Cynoscion striatus in the sea and in aquaria. The monthly growth of these juveniles in the sea was determined by means of the analysis of length‐frequency distributions of 5500 individuals throughout the year. Fish in aquaria were measured and weighed every two weeks, and were fed on known amounts of food. The relationship between the length and the weight of fish, and between the length, width and thickness of the otoliths and the length of fish were calculated and were expressed as exponential functions. On the basis of the analysis of length‐frequency distributions and of back calculations it was determined that the formation of the first annulus in the otoliths of juveniles of this species occurs in specimens of 45–100 mm in length and of 1.16–10.0 g in weight. In the majority of the individuals the first annual ring was formed at a size of about 70–80 mm. In juveniles of 79–102 mm, at a temperature of 15–22° C, the maintenance requirement was 0.189 g, and the gross efficiency is 0.310 g of shrimp per gram fish per week. The efficiency of food conversion is high, its value being of 18.8%. The increment in length in these juveniles was 2.01 mm per week and the increment in weight was 0.896 g per week.
Parental influence on growth rate, smolting rate and survival in hatchery reared juvenile Atlantic salmon, Salmo salar
Authors: Thorpe J. E. , Morgan R. I. G.
Published: January 2006

The proportion of potential 1‐year smolts, their mean length, the mean length of potential 2‐year smolts, and the mortality rate in four half‐sib families of Atlantic salmon, reared under four contrasted conditions of overhead cover, is shown to be inffuenced primarily by genetic factors (89.9%, 86.1 %, 82.7% and 80.2% of total variance respectively). Variation between families in smolting rate and mortality rate is influenced by both parents, but more by the male than the female. Variation in mean length is influenced almost entirely by the female parent. These results are discussed in relation to previous findings on bimodality of size distribution and inheritance of growth and mortality characteristics in Atlantic salmon.
Cystidicola farionis as a swimbladder parasite of the whitefish in the Bothnian Bay
Authors: Valtonen E. T. , Valtonen T.
Published: January 2006

Material comprising 3167 specimens of the parasite Cystidicola farionis was assembled from 1741 individuals of the sea‐spawning whitefish, Coregonus nasus in the shallow northeastern and deeper central areas of the Bothnian Bay. Occasional parasites were found in the immature fish (≦ 175 mm), but infection increased in the two larger classes as the fish aged, reaching 27% in the northeastern area, and as much as 67% in the southern area. This difference is explained partly by the more frequent feeding on Pontoporeia affinis, the intermediate host for the parasite, the deeper waters extending nearer the coast in the majority of the central and southern Bothnian Bay. The increased intensity of infection with age does not vary significantly between the areas studied. No clear seasonal fluctuations in the prevalence or intensity of infection could be found.
Accumulation of the organophosphate blackfly larvicide Abate (temephos) in Sarotherodon mossambicus, with reference to the larvicidal control of Simulium damnosum
Authors: Matthiesen P. , Johnson J. S.
Published: January 2006

This paper describes the uptake and fate of the organophosphate larvicide Abate (temephos) in the tropical food fish, Sarotherodon mossambicus (Peters), during exposure to concentrations (nominally 0.001–0.1 mg dm−3) similar to those being produced in West African rivers by the WHO Onchocerciasis Control Programme. S. mossumbicus was able to absorb Abate both directly from the surrounding water, and by contaminated food. Maximum residue concentrations were proportional to dosage and were elevated in starving fish. Internal distribution depended on tissue fat content. Some fish produced the sulphoxide metabolite, and total residues diminished slowly during recovery.
The effect of copper, hardness and pH on the growth of rainbow trout, Salmo gairdneri
Authors: Waiwood K. G. , Beamish F. W. H.
Published: January 2006

Rainbow trout (Salmo gairdneri) were held at a ked ration and activity regime and were exposed to a number of copper, pH and hardness combinations. Growth rate, appetite and gross conversion efficiency were determined over three consecutive 10‐day periods of exposure. Growth rate was most affected during the first 10 days of exposure and partial or complete recovery was observed thereafter. For a given pH, less copper was required to reduce growth by a given amount at low than at high levels of hardness. At a given hardness, copper‐induced depressions in growth rate were more pronounced and recovery slower in a low than in a high pH. No distinction could be made among total soluble or extractable copper but predicted concentrations of six specific cupric ions varied with pH and hardness. Regression analysis indicated that only Cu2+ and CuOH+ could be significantly correlated with growth rate.
Biochemical changes in the lateral muscles of roach, Rutilus rutilus from two habitats following exercise
Authors: Broughton N. M. , Goldspink G.
Published: January 2006

Batches of roach from two contrasting habitats were exercised in a flume at various water velocities for 1 h, and muscle metabolite levels were determined. It was found that the percentage change in lactate was greater in fish from the still water habitat than that in their running water counterparts, and it is proposed that natural conditioning of fish to water flow may be one of the main factors responsible.
Dietary habits of fish populations in the Lower Medway Estuary
Authors: van den Broek W. L. F.
Published: January 2006

Populations of mainly first‐year fish overwinter in the Medway Estuary, an area offering shelter and a rich and varied food supply. In the absence of previous investigations, the present study examines the dietary habits of four fish species; gadoids Merlangius merlangus and Trisopterus luscus, and pleuronectids Platichthys flesus and Pleuronectes platessa.

Gadoids fed predominantly on fast moving nektonic organisms such as brown shrimps, mysids and fish while pleuronectids preferred the slower moving tubificid and polychaete worms. Seasonal fluctuations of the dietary constituents are considered in relation to changes within the populations of both prey and predator organisms.
Epithelial carcinoma in Anabas testudineus
Authors: Pal J. , Pal B. C. , Bannerjee R.
Published: January 2006

Histological examination of a skin tumour from Anabas testudineus indicated its carcinogenic nature. Two types of bacteria were isolated from the tumour and adjacent tissue.
Zinc content of the gills of rainbow trout (S. gairdneri) after treatment with zinc solutions under normoxic and hypoxic conditions
Authors: Hughes G. M. , Flos R.
Published: January 2006

Forty specimens of rainbow trout (54–127 g) were divided into 4 groups which were treated as follows: (a) normoxic clean water; (b) hypoxic clean water; (c) normoxic water with 10 ppm zinc for 10 h; (d) hypoxic water with 10 ppm zinc for 10 h. The zinc content was determined separately for each of the 4 gill arches on each side of the fish. Values for the zinc concentration were greater following the zinc treatments, but no significant difference between hypoxia and normoxia was observed. Differences in concentrations of zinc were found in different arches whether expressed per gram dry weight or per unit surface area of the secondary lamellae.
Preliminary observations on different reproduction strategies in the bullhead (Cottus gobio L.) in northern and southern England
Authors: Fox P. J.
Published: January 2006

The size distribution and numbers of oocytes were examined in samples of ovaries from two sites and in fish in tanks whose past spawning activities were known. In an upland stream in northern England Cottus gobio would seem to be an annual spawner, maturing a single batch of eggs each year. In a more productive stream in southern England, where the reproductive life is short, fish mature and lay a succession of batches of eggs during a long spawning season. The physiological and ecological implications of these characteristics are discussed.
Changes of blood enzymes in brook trout induced by infection with Aeromonas salmonicida
Authors: Shieh H. S.
Published: January 2006

Furunculosis was induced in brook trout, Salvelinus fontinalis, by experimental inoculation with Aeromonas salmonidda. The levels of blood enzymes were determined and the most significant modifications were observed for aldolase, creatine phosphokinase and ornithine carbamyl transferase. Alkaline phosphatase, glutamic‐pyruvic transaminase and glutamic‐oxalacetic transaminase showed minor modification. There was no significant change of activity for acid phosphatase, cholinesterase, lactic dehydrogenase, phosphohexose iso‐merase, isocitric dehydrogenase and aminopeptidase.
Occurrence of the periodic acid‐Schiff positive granular leucocyte (PAS‐GL) in some fishes and its significance
Authors: Louise Barber D. , Mills Westermann Jean E.
Published: January 2006

Preparations of peripheral blood of 58 species of fish, mostly teleosts, were examined for the presence of granulocytes. Heterophils are commonly found but eosinophils are rare and metachromatic basophils never seen. Granulocytes (PAS‐GL) with periodic acid‐Schiff positive granules, were observed in 30 species representing marine and freshwater, and ‘primitive’ and ‘advanced’ types. It is postulated that the PAS‐GL is the piscine forerunner to the heparin and histamine‐containing metachromatic basophil/mast cell of higher vertebrates.
LDH isoenzymes in the axial muscle of the sharks Galeus melastomus and Etmopterus spinax
Authors: Totland Geir K. , Kryvi Harald , Slinde Erik
Published: January 2006

The lactate dehydrogenase isoenzyme patterns have been studied in the axial muscles of the sharks Etmopterus and Galeus. Samples from red, intermediate and white muscle fibres were run separately on a polyacrylamide slab‐gel. Both sharks have three isoenzymes; all three are present in the red and intermediate fibres, while the white fibres contain only the two slowest‐moving isoenzymes. The red fibres of both sharks contain most of the fastest‐moving isoenzyme.

The isoenzymes have a high tolerance towards urea; the slow moving isoenzyme is inhibited at about 2 m urea, the next isoenzyme at 4‐6 M urea, and some activity of the fast‐moving isoenzyme is still present at 10 M urea in the incubation medium. The LDH distribution in the fibre types is studied by histochemistry on frozen sections.
A note on the growth of two exotics in England; the silver carp (Hypophthalmichthys molitrix Val.) and the bighead (Aristichthys nobilis Rich.)
Authors: Stott B. , Buckley B. R.
Published: January 2006

Observations were made on the growth of microphagous silver carp and bigheads in a tank housed under a horticultural polythene tunnel. It is suggested that the species may be of interest for cultivation and might also be useful in removing nutrients from eutrophic waters in the United Kingdom.
Growth and movements of the twaite shad, Alosa fallax (Lacépède), in the Severn Estuary
Authors: Claridge P. N. , Gardner D. C.
Published: January 2006

Between July 1974 and April 1977, appreciable numbers of 0 group twaite shad, Alosa fallax, have been collected from the cooling water intake screens of the Nuclear Power Stations at Oldbury‐upon‐Severn and Berkeley on the Severn Estuary and at Hinkley Point on the Bristol Channel, England. Young of the year first appeared at Oldbury in July at a size of approximately 32 mm standard length, and grew to approximately 61 mm by October. The downstream migration in the late summer and autumn appeared to be closely correlated with water temperature since movement reached a peak soon after the temperature in the Estuary had declined below 19° C, and ceased altogether below 9° C. Thereafter, there was virtually no movement of shad until temperatures rose sharply above 7° C in the spring. Maturing adult twaite shad were captured in late April and May as they moved into freshwater to spawn, probably in mid‐June. Males were recorded slightly earlier during the migration and were generally younger than females. Furthermore, mean lengths and weights for individuals belonging to the different age classes indicated that males were also smaller. Logarithmic relationships between length and weight of young and adult A. fallax and for the variation with size in the number of rakers on the first gill arch are presented.
Aspects of the biology and heavy metal accumulation of Ciliata mustela
Authors: Badsha K. S. , Sainsbury M.
Published: January 2006

The feeding habits, rates of growth, fecundity and other aspects of the general biology of five‐bearded rockling from the Severn Estuary and the Bristol Channel are reviewed for the period 1974/76. Additionally the changes in heavy metal accumulation during this time have been measured and an attempt has been made to relate them to the diet of the fish.
The effects of insulin on plasma amino acid levels in the Northern pike, Esox lucius L
Authors: Ince Bernard W. , Thorpe Alan
Published: January 2006

Cod and bovine insulin (2 i.u. kg−1) were injected intra‐arterially into cannulated Northern pike, Esox lucius L. and the levels of 13 plasma amino acids analysed by gas‐liquid chroma‐tography after 9 and 48 h. Both insulins caused an equally significant reduction in the level of each amino acid after 9 h which was followed by a recovery to near‐control levels after 48 h. The data support the hypothesis that insulin plays a major role in the regulation of protein metabolism in this species.
Circadian rhythms in juvenile american shad, Alosa sapidissima
Authors: Katz H. M.
Published: January 2006

Swimming activity (in cm s−1) of a school (55 individuals) of young‐of‐the‐year (x̄ total length=110 mm) American shad, Alosa sapidissima, was determined under a variety of photoperiod conditions. These included a normal (ambient), a shifted, and constant‐light day. Swimming activity was measured over 4‐day periods. During normal days swimming speeds followed periods of about 24 h, with fast speeds (up to 45 cm s−1) and schooling occurring during the photoperiod. Under dark conditions speeds were slower (8 cm s−1) with most fish swimming as individuals. During a shifted day swimming speeds and schooling corresponded to the imposed day. Under constant light (equivalent to bright moonlight) no schooling was evident, and a constant, but slow, swimming speed was observed in each 24‐h period. These shad demonstrated an exogenous rhythm with respect to the imposed day length. It is hypothesized that an endogenous circadian rhythm would only be of use to a fish required to hunt or chase its prey. Shad, being plankton feeders, do not chase prey and therefore can exhibit an exogenous circadian rhythm with no detrimental feeding results.
Intestinal Histology of Dorosoma cepedianum
Authors: Jilek Reid
Published: January 2006

The intestinal histology of D. cepedianum was examined by light microscopy. The results are discussed in relation to previous findings.
The movement of hatchery‐reared rainbow and brown trout in a polluted river in the South Wales coalfield
Authors: Scullion J. , Edwards R. W.
Published: January 2006

Hatchery reared rainbow and brown trout (length 20 cm) were released in March 1974 and April 1975 respectively into the Taff Bargoed, a small river in South Wales, polluted by coal wastes and containing a low resident population of brown trout. From subsequent electro‐fishing surveys and catch returns from anglers, extensive downstream movements occurred in both species. About 50% had either been caught or had moved out of the river, a distance of about 5 km, after two weeks and after two months only some 10 % remained. Within the fishing season it was estimated that 3 and 22% of brown and rainbow trout respectively were caught.
The immunoglobulin of the brown trout, Salmo trutta and its concentration in the serum of antigen‐stimulated and non‐stimulated fish
Authors: Ingram G. A. , Alexander J. B.
Published: January 2006

Immunoglobulin production in the primary and secondary immune response of brown trout to keyhole limpet haemocyanin has been investigated including the effect of dose size, route and number of injections, and the use of adjuvant. Antibody activity was found in the first fraction from Sephadex G200 and in the second from Sepharose 6B. Trout immunoglobulin had β2—Γ1 electrophoretic mobility, and Sapp of 16·7 and an approximate molecular weight of 670 000 daltons. It was sensitive to dithiothreitol and stable at 56°C for 30 min. Immunoglobulin concentrations were measured by single radial immunodiffusion with a specific rabbit antiserum. Sera from non‐injected trout had a mean immunoglobulin level of 7·3 ± 0·3 mg ml−1 which accounted for 10% of the total serum protein. Phosphate buffered saline‐injected controls contained 6·7 ± 0·2. In fish given a single injection the mean concentration ranged from 7·5 to 12·9 and in those given more than one injection from 12·6 to 16·8. The use of adjuvant resulted in higher immunoglobulin concentrations. Neither dose nor route had any significant effect on the primary response. However, in the secondary response the intramuscular route resulted in significantly increased immunoglobulin production.
The haemodynamics of gas resorption from the physoclist swimbladder: the structure and morphometrics of the oval in Pollachim virens (L).
Authors: Ross L. G.
Published: January 2006

The structure of the oval in saithe is described with particular reference to its vascularisa‐tion. The extent of the capillary plexus was found to be greater than previously estimated, covering about 40% of the internal surface area of the bladder. Morphometric assessment of the capillary network enabled estimation of flow rate using the Poiseuille equation. The low potential flow suggested in this work may be a limiting factor in gas loss from the swimbladder and may place restraints on vertical migration.
Strontium marking of hatchery‐reared coho salmon (Oncorhynchm kisutch, Walbaum)
Authors: Yamada S. Behrens , Mulligan T. J. , Fairchild S. J.
Published: January 2006

In the management of saimonid populations it is often necessary to distinguish hatchery‐reared from wild stocks. This study examines the feasability of marking fish tissue by substituting a biologically rare element, strontium, for calcium.

Sixteen‐month‐old hatchery‐reared coho salmon (Oncorhynchus kisutch, Walbaum 1792) were fed a diet, to which 10000 ppm stable strontium was added, for 60 days. Prior to their seaward migration in June 1976, the treated coho contained 32 times as much strontium in their vertebrae as did the control coho.

Sixty‐eight precocious males‘jacks’ returned to the hatchery in the fall of 1976 and 1200 adults in the fall of 1977. Strontium‐treated ‘jacks’ contained 1·4 times as much strontium as did control ‘jacks’ however, treated and untreated fish could not be distinguished as adults. The reduction in the strontium concentration of the treated fish could be accounted for by growth.
The use of chemosenses by threadfin shad, Dorosoma petenense to detect conspecifics, predators and food
Authors: McMahon Thomas E. , Tash Jerry C.
Published: January 2006

The abilities of threadfin shad (Dorosoma petenense) in using chemosenses to detect the scents of conspecifics, a predator and food were tested in the laboratory. Shad did not respond to the scents of conspecifics or a predator; possibly because both shad and their predators out‐swim such cues as chemical scents that are transmitted slowly through the water. Shad showed a strong attraction to the scents of food. In feeding, chemosenses may be used for filter feeding on microscopic food and for locating food beyond the range of vision.
Resistance to cadmium by pretreated rainbow trout alevins
Authors: Pascoe D. , Beattie J. H.
Published: January 2006

A toxicity test with cadmium concentrations ranging from 0·1 to 100·0 mg Cd 1−1 was used to assess the effect of cadmium pretreatment on rainbow trout (Salmo gairdneri Richardson) alevins. The median period of survival for fish pretreated at 0·01 mg Cd 1−1 was found to be increased at test concentrations up to 10mg Cd 1−1 compared with alevins pretreated with dilution water. However, at concentrations above 10mg Cd 1−1 pretreatment at 0·01 mg Cd 1−1 reduced the median period of survival.
The role of food particle size in the growth of juvenile Atlantic salmon (Salmo salar L.)
Authors: Wańkowski J. W. J. , Thorpe J. E.
Published: January 2006

The effect of particle size of a commercial pelleted feed on the growth of Atlantic salmon from first feeding alevins to first and second year smolts was investigated using 20‐day feeding experiments. Ten experiments were performed over a two year period, each comprising six groups of fish separately selected from stock populations. Each group was presented with one of six sizes of food particle ranging from larger than the respective mean mouth breadth (100% feed size), through 50%, 25%, 12·5%, 6·25% to 3·125%. Experiments were performed in six radial flow/circumferential drain tanks under ambient photoperiod and water temperature. Growth rate was found to be closely related to feed size. Maximum growth in each case was shown only on one size of particle; larger and smaller sizes resulted in reduced growth. The particle size for maximum growth increased in direct proportion to fish length. Fish from 4·2 to 20·3 cm in length showed maximum growth on particle diameters 0·022 to 0·026 × fish fork length (PFR). First feeding alevins were found to show comparable growth rate on particle diameters 0·0115 to 0·090 PFR. Some seasonal variation in growth response was indicated. The results are discussed in relation to developmental and seasonal effects. Possible factors affecting the energetics of prey size related differential growth are discussed.
The haemodynamics of gas resorption from the Physoclist swimbladder. II. The determination of blood flow rate in the oval of Pollachius virens (L.) using radiolabelled microspheres
Authors: Ross L. G.
Published: January 2006

An attempt has been made to assess blood flow in the oval region of P. virens using radiolabelled microspheres. The results suggest a low flow rate and they are similar to those calculated using the Poiseuille equation in a previous paper. A substantial increase in flow rate was obtained on inflation of the bladder, showing that the deflating reflex was elicited.
Seasonal variations in the blood constituents of an air‐breathing fish, Channa punctatus Bloch
Authors: Mahajan C. L. , Dheer J. S.
Published: January 2006

A year long study based on monthly observations on the haematology of female Channa punctatus with respect to haemoglobin, haematocrit values, total erythrocyte and leucocyte numbers together with a differential enumeration of various leucocytes viz. thrombocytes small and large lymphocytes, monocytes, neutrophils, eosinophils and basophils is recorded. The study showed that the total erythrocytic number, haemoglobin and haematocrit values decrease during the breeding time i.e. July to September. The thrombocyte number significantly increased while the neutrophilic number showed a decrease. The physiological significance of these changes is discussed with reference to the available literature.
Observations on the breeding biology of Sarotherodon macrochir (Boulenger) in Lake Mcllwaine, Rhodesia
Authors: Marshall B. E.
Published: January 2006

Sarotherodon macrochir matures at 17–18 cm standard length in Lake Mcllwaine and males grow larger than females. There is an extensive breeding season with the main breeding taking place during September‐February, the hottest period of the year, which is just before the rainy season. Female S. macrochir produce about 1000 to 5000 eggs in their ovaries and can brood up to 800 eggs in their mouths. Mean brooding efficiency is about 75 % but this declines as the fish increase in size.
Photokinetic responses and diel activity of sea lamprey Petromyzon marinus ammocoete larvae
Authors: Reynolds W. W. , Casterlin M. E.
Published: January 2006

Twenty‐four ammocoete larvae of the sea lamprey Petromyzon marinus were tested individually for 3‐day periods in electronic shuttleboxes (Ichthyotrons) with natural lighting through windows, to determine their diel activity pattern in terms of hourly percentages of the 24‐h total. Mean hourly activity was slightly greater during the day (4–7 % h−1) than at night (3·7% h−1). Peak hourly activity (7·2% h−1) occurred during the dawn crepuscular period as light levels were increasing, while the minimum hourly activity (1·6 % h‐l) occurred during the dusk crepuscular period while light levels were decreasing. The observed activity pattern is atypical of other aquatic animals similarly tested, and might be explained as an extraptically mediated photoinetic response.
Studies on the biology of reproduction in the cichlid Tilapia nilotica (L.): effects of steroid and trophic hormones on ovulation and ovarian hydration
Authors: Babiker M. M. , Ibrahim H.
Published: January 2006

The effects of intraperitoneal injections of cortical and ovarian steroids and trophic (mammalian) hormones on ovulation, ovarian hydration and the distribution of sodium ions in muscles and ovary was studied in Tilapia nilotica. Cortisol, corticosterone and oestradiol 17p (50–250 mg kg−1 B.W.) induced ovulation in a dose‐dependent manner and increased the degree of hydration of muscle and ovarian tissues. The sodium ion content of muscles was reduced and that of ovaries increased following treatment with these hormones. Oestrone, oestriol and progesterone (60–245 mg kg−1 B.W.) failed to induce ovulation but produced the same types of effects on the water and sodium ion content of muscles and ovaries as the other steroids. Human chorionic Gonadotrophin, HCG, (1200–12 000 I.U. kg−1 B.W.) also induced ovulation and increased the degree of hydration of muscles and ovaries and increased the sodium ion concentration in ovarian and reduced that of muscle tissues. Pregnant Mare Gonadotrophin, PMG, in doses similar to those of HCG, did not induce ovulation in any of the treated fish and did not significantly alter the water or sodium ion content of muscles and ovaries.
The occurrence and natural alleviation of stunting in a population of roach, Rutilus rutilus (L.)
Authors: Burrough R. J. , Kennedy C. R.
Published: January 2006

Two sudden and pronounced changes in the growth rate of roach, Rutilus rutilus (L.), in Slapton Ley, Devon, have been observed between 1972 and 1976. At first the growth rate declined to the point at which the population became stunted, then subsequently it improved again. These changes were correlated with population density; the numbers of roach were increasing during the late 1960's/early 1970's, and this increase was substantially reinforced by very strong year classes in 1972, and, to a lesser extent, in 1973. The increase in population density resulting from the strong 1972 year class was apparently adequate to accelerate the onset of the stunting observed. The improvement in growth rate in 1976 followed immediately after extensive mortalities amongst the roach during 1975, caused by an epidemic of the parasite Ligula intestinal is (L.). Some improvement in the growth of O group roach had been evident during 1975, but this was not observed in the population. Ford‐Walford plots showed a decline in the value of L after the onset of stunting in 1972.

Differences in the reproductive biology of the fish were found following the alleviation of stunting; the gonads of both sexes achieved a greater relative weight, and correspondingly the fecundity of the females was higher, although this latter effect became progressively less marked with increasing size. It was not apparent amongst the largest individuals. There was also some evidence of a decline in the proportion of fish maturing at minimum size. The changes in the reproductive biology were associated with the improvement in conditions for individual fish following the decline in population density.
Serum antibiotic levels in adult sockeye salmon as a function of route of administration
Authors: Strasdine G. A. , McBride J. R.
Published: January 2006

Adult sockeye salmon, Oncorhynchus nerka (Walbaum), in three different stages of sexual maturity were administered the antibiotic, oxytetracycline, by injection (intraperitoneal and intramuscular), water bath exposure and stomach capsule implant. Concentrations of the antibiotic in, and its disappearance from the serum were determined. For all three stages of sexual maturity the most efficacious route of administration based on maximum titre and duration in the serum was provided by intraperitonial injection. Intramuscular application produced a positive effect, albeit at a markedly lower level, in all three groups of fish. Oral implants resulted in only a minor uptake of the antibiotic in the fully ripe fish. Immersion of the fish in water solutions of oxytetracycline was without effect.
The embryonic development and the thermal effects on the development of the mountain whitefish, Prosopium williamsoni (Girard)
Authors: Rajagopal P. K.
Published: January 2006

The general development of the mountain whitefish was similar to other whitefishes. Mountain whitefish required more thermal units to reach corresponding stages of the lake whitefish, after the stage when the blastodisc was prominently raised on the yolk. The development process was greatly disrupted and a heavy mortality of eggs occurred when the temperature was raised to 9° C or higher. In hatched larvae abnormalities like monomicrophthalmia, agape jaws, and coloboma occurred when the temperature was raised to 9° C or higher, although the reported optimum temperature for growth of the post yolk sac larvae and juveniles was 9° C‐12° C. The late spawned eggs exhibit adaptive mechanisms which enabled them to shorten the incubation time and hatch along with the early spawned eggs, when conditions for survival are at optimum.
Observations on feeding, growth and electric discharge of newborn Torpedo ocellata (chondrichthyes, batoidei)
Authors: Michaelson D. M. , Sternberg D. , Flshelson L.
Published: January 2006

Newly born and neonate Torpedo ocellata were obtained from gravid females caught during the autumn off the Mediterranean coast of Israel. The young torpedos, which weighed about 11 g, were fed with live Blennius pavo Risso, and doubled their weight in about 4 months. The behaviour of the torpedo during feeding was examined and photographed. When attacking a fish, the torpedo emerges from being buried in the sand and assaults the approaching prey. First, the prey is trapped under the torpedo and then directed towards the ray's mouth by its body movements. Newborn and neonate torpedos are able to discharge their electric organ. The amplitude of the discharge of one day‐old fish is approximately 4 V. It increases dramatically during the first three weeks of life to 20 V, reaching an asymptotic level of about 26 V, by the end of the fourth month.
Recruitment and turnover of populations of brown trout, Salmo trutta, in the upper River Wye, Wales
Authors: Milner N. J. , Gee A. S. , Hemsworth R. J.
Published: January 2006

The age structure, abundance, net immigration and loss of trout populations were investigated in eleven tributary sites and two main river sites on the River Wye. Marking experiments indicated that recruitment to the site populations was mainly by immigration which began during the O‐group phase and continued, with seasonal fluctuations, throughout life. Immigrant fish had a higher probability of being lost from the populations than residents providing a statistical distinction between mobile and sedentary components of the population. The turnover of the site populations is described using a simple exponential model, and half‐times at different sites (stream length, 50 m) ranged from 140 to 430 days. Some factors affecting half‐times are briefly discussed.
Some studies on the hepatic microsomal enzyme activities and steroid hormone levels in carp, Cyprinm carpio exposed for six months
Authors: Sivarajah K. , Franklin C. S. , Williams W. P.
Published: January 2006

A short‐term study from October 1975 to April 1976 was carried out by keeping 10 carp in two separate cages (five in each) at each of the three sites, namely, Wraysbury Reservoir, Ryemeads Sewage Lagoon and Deephams Sewage Lagoon (Fish unit). Fish were not artificially fed. Blood samples were collected at monthly intervals. Activities of the following hepatic microsomal enzymes, aminopyrine demethylase, p‐nitro‐reductase, UDP‐glucurony! transferase and 1‐leucyl‐p‐naphthylamide splitting enzymes were measured; cytochrome P450 and microsomal protein contents were also estimated.

The levels of androgens, oestrogens and corticoid hormones were measured in the circulating blood at monthly intervals. Results indicated that there was (a) no significant increase in the activities of all the enzymes measured except for an increase in cytochrome P450 in the fish kept at Deephams Sewage treatment works, (b) no significant increase in microsomal protein content at the three sites and (c) no significant changes in the levels of plasma androgens, oestrogens and corticoids of the circulating blood.
Alkaline phosphatase activity in the skin of the Common goby, Pomatoschistus microps (Krøyer), in relation to cycles in scale and body growth
Authors: Fouda M. M. , Miller P. J.
Published: January 2006

A histochemical study of the distribution of alkaline phosphatase in the skin of the Common goby, Pomatoschistus microps, showed that the enzyme is present in the dermis, not in the epithelium, and is more pronounced around the growing edge of the scale and below the fibrillary plate. The intensity of the enzyme reaction is higher in regenerated scales. In conjunction with the phenology of P. microps, a method was adopted to measure the enzyme activity in the skin, including scales, for successive months over a period of two years. Enzyme activity displayed seasonal fluctuations which were closely related to both body and scale growth. Enzyme activity also reflected other phenological cycles during the life‐span of P. microps.
Changes in the rate of growth in a stunted roach Rutilu rutilus population
Authors: Linfield R. S. J.
Published: January 2006

Data is presented concerning the growth of roach in a South Lancashire lake. Results from a sample of roach in May 1969 indicate the slowest growth rate for which published records are available. A comparison of the length/age and weight/age relationships between data for May 1969 and May/June 1971 yields significant between‐year differences indicating an increase in the growth rate during that period. A study of the growth history of individual year classes using back‐calculated values from operculum measurements suggests that for both sexes the observed increase in the rate of growth commenced after the 1965–67 period during which very weak year classes were produced. The mean length of females appears to have been larger than that of males from the age of four onwards but the 95% confidence intervals are almost totally overlapping for each pair of values and a statistical comparison of growth rates between the sexes indicates no significant differences. Data for the sexes combined is compared with published results from other British and Continental waters.
Effects of temperature and stocking density on food consumption and growth of grass carp Ctenopharyngodon idella, Val.
Authors: Kilambi R. V. , Robison W. R.
Published: January 2006

Grass carp were raised in 227 1 indoor tanks at 12.8, 18.3, 23.9 and 29.4° C temperatures, each experimental condition received five fish. Five grass carp were also raised in a 1135 1 tank maintained at 29.4° C representing low stocking density (29.4° C‐L). Food consumption, food conversion, and growth of carp were not different among the 18.3, 23.9, and 29.4° C experimental conditions with identical stocking density. The least growth and food consumption were noted for the fish at the 12.8° C temperature. The fish at the low stocking density had the best growth and maximum food consumption.
Food habits of yellowtail flounder, Limandaferruginea (Storer)
Authors: Libey George S. , Cole C. F.
Published: January 2006

Yellowtail flounder, Limanda ferrugunea, were collected from the waters north of Cape Ann, Massachusetts, from April 1971 to January 1972. Cumaceans were the most important food item in the spring. Amphipods and polychaetes, as well as cumaceans, were the main foods consumed in other seasons. Large volumes of plant detritus, sand, and pebbles were present in the stomachs throughout the year. The highest percentage of empty stomachs coincided temporally with the spawning season, although the frequency of occurrence was low at all times. There were no differential food habits by sex or age.
The gill sialic acid content as an index of environmental stress in rainbow trout, Salmo gairdneri, Richardson
Authors: Arillo A. , Margiocco C. , Melodia F.
Published: January 2006

The gill sialic acid content in Rainbow Trout exposed to several aqueous concentrations of ammonia NH3 and/or to a high environmental pH was determined by two different methods. The results showed Warren's method was adequate for the biological material, even without purification of the extracts by Dowex 2.8 resin. A significant increase of the sialic acid concentration occurred in fish exposed to ammonia.
Role partitioning of swimming musculature of striped Bass Morone saxatilis Walbaum and Bluefish, Pomatomus saltatrix L.
Authors: Freadman M. A.
Published: January 2006

Electromyography was used to determine the functional roles of the axial musculature in striped bass and bluefish at imposed swimming velocities. The lateral red muscle powers propulsive movements at all sustainable swimming speeds in both species. The amplitude and frequency of EMG's from the red muscle grade with increasing swimming velocity. The white muscle, forming the main mass of the myotome, is reserved for high‐speed burst swimming above maximum sustainable speeds. The proportion of the myotome occupied by the red muscle at the level of the caudal peduncle is 10.9% and 18.6% for the striped bass and the bluefish respectively.
Aspects of the biology of Sprattus sprattm (L.) in the Medway Estuary
Authors: van den Broek W. L. F.
Published: January 2006

Fish samples were taken monthly over an eight‐hour day period between 1973 and 1975. In addition, separate night samples were collected during 1974–75. The present study considers the sprat component of the catch and examines aspects of the fish's biology and its accumulation of chlorinated hydrocarbon compounds and heavy metals.

Sprats were present on every sampling date and, generally, totals were highest during late autumn/early winter. They formed 61.1 % of the catch by numbers and 17.5% by weight. Night samples contained an unexpectedly large number of sprats and with mean lengths significantly greater than those in day samples. Changes in monthly length‐frequency distributions suggested double spawning during 1974, perhaps the result of a mild winter.

Sprats were infected with two copepod ectoparasites; Lernaeenicus sprattae (Sowerby) and L. encrasicola (Turton). In each case infection was low, affecting only 6.6 and 0.9% of the population respectively. Levels of chlorinated hydrocarbons and heavy metals were also low in whole sprat tissue. Values of DDDT, dieldrin and PCBs were at a maximum in winter and minimum in spring. Heavy metal results showed no seasonal pattern.