bluuebunny/crossref_metadata_2025 huggingface dataset:
The ultrastructural organization of olfactory epithelium of two species of gadoid fish
Authors: Lowe G. A. , MacLeod N. K.
Published: January 2006

The untrastructural organization of the olfactory epithelium of the cod Gadus morhua (L.) and the haddock Melanogrammus aeglefinus (L.) was studied using both transmission and scanning electron microscopy. The olfactory rosette was found to exhibit regional differences; the faces of the olfactory lamella were composed of sensory epithelium, the edges were non‐sensory. The cellular organization of the olfactory epithelium was determined and consisted of bi‐polar sensory neurones, supporting cells, mucous cells and basal cells. The ultrastructure of the sensory cells was consistent, having an elongate cell, the free surface of which terminated in an olfactory vesicle from which arose either four olfactory cilia or numerous microvilli. Ciliary aggregations have been found in the two species of gadoid fish studied; it is suggested that these structures aid in the separation and in the circulation of fluid between the lamellae. The surface structure of the supporting cells was found to be of two types: either ciliated or ridged; the former presenting distinct ciliated tufts, the latter showing definite, but unorganized, ridges over the epithelium surface.
The immune response in fish: a review
Authors: Corbel M. J.
Published: January 2006

The literature relating to the immune response of fish has been reviewed. Non‐specific immune mechanisms similar to those of other vertebrate classes occur in fish. Similarly specific cell‐mediated immunity has been demonstrated at all levels of evolution, from the cyclostomes to the teleosts. A humoral antibody system also occurs in all classes offish but varies considerably in relation to phylogenetic status. In the cyclostomes, only immuno‐proteins with properties intermediate between the immunoglobulms of vertebrates and the non‐specific agglutinins and lysins of invertebrates have been demonstrated. In the elasmo‐branchs and chondrosteans 7 and 19s irnmunoglobulins of IgM type occur. In holosteans the 19s form is predominant whereas in teleosts, 7 and 19s forms occur, with some evidence of specialization in the 7s form. In the phylogenetically most advanced fish, the Dipnoi, two immunoglobulin classes, structurally analogous to IgM and IgG, have been described.

A characteristic feature of both cell‐mediated and antibody mediated immune responses in fish is their dependence upon environmental temperature. There is also evidence that, in some species at least, nutritional factors and behaviour patterns may also influence the immune response.

Attempts at artificial immunization of fish against infectious disease have met with varied success. It is probable that better results could be achieved with live vaccine strains, particularly if applied under conditions optimal for the immune responses.
The effect of different levels of dietary fat on the growth of rainbow trout (Salmo gairdneri Richardson)
Authors: Atherton W. D.
Published: January 2006

Two types of fat, represented by cod liver oil and lard, were added at various levels to the diet of rainbow trout. The food intake of the trout and their growth rate were measured. The results indicated that when cod liver oil was used as the fat supplement, the amount and the water temperature affected food intake and weight gain; fish fed on lard showed only a slight loss of appetite.
The populations of fish in the River Tees system on the Moor House National Nature Reserve, Westmorland
Authors: Crisp D. T. , Mann R. H. K. , McCormack Jean C.
Published: January 2006

The age, growth, population densities and annual production of an isolated population of brown trout (Salmo trutta L.) and bullhead (Coitus gobio L.) were investigated over a 5 year period in Trout Beck in the northern Pennines. Additional data were obtained from two other sites; Great Dodgen Pot Sike and the River Tees.

Trout growth rates were low, particularly in Dodgen Pot Sike, but ages up to VIII were recorded. Bullhead growth rates were similar to those in the Tees at Cow Green (Crisp et al., 1974), though the Moor House bullheads had a higher survival rate. Population densities of trout ranged from 0.10–0.22/m2, with a fry contribution of 0.80%. The bullhead population in Trout Beck was sparse, generally 0.1/m2, though an 0 group value of 0.46/ma was estimated in 1967. At Tees Bridge values ranged from 2.5–7/8/m2. Most trout matured by age III, though in Great Dodgen Pot Sike only half of the females were mature at age IV.

Annual production was estimated from Allen graphs. Trout production ranged from 1.02–3.50 g/m2/year, the fry contributing up to 51.5% of the total. A value of 0.48 g/m2/year was obtained for bullheads in the Trout Beck system in a year of good recruitment, whilst bullhead production at Tees Bridge was 7.43 g/m2/year, with fry and I group contributing 48.7 and 37.5% respectively. The high survival rate, irregular recruitment, and poor growth of these high altitude populations is discussed. Growth and reproductive peculiarities of the Great Dodgen Pot Sike trout are also discussed.
Cytogenetic studies of Poecilia (Pisces)V. Cytophotometric evidence for the production of fertile offspring by triploids related to Poecilia formosa
Authors: Strommen Carol A. , Rasch Ellen M. , Balsano Joseph S.
Published: January 2006

To monitor the perpetuation of triploid genomes in laboratory‐reared progeny of wild‐caught females of Poecilia, amounts of DNA‐Feulgen staining in scale epithelial nuclei were determined for 58 different fish. Based on estimates of average DNA content, these specimens were readily separated into two groups: (a) diploids, with an average of 1–57 × 10−12 g DNA per cell and (b) triploids, with an average of 2.38 × 10−12 g DNA per cell. These values yield a ratio of 1: 1.5, as would be expected from the presence of an extra chromosome set in putative triploid females. Ploidy status of the latter, based on DNA cytophotometry, was independently confirmed for several specimens by direct cytological examination of chromosome number, by electrophoresis of plasma proteins and by morpho‐metric analysis. These findings unequivocally document one case involving the production of triploid offspring from a typical, diploid P. formosa and several instances in which broods of all‐female triploid offspring were derived in the laboratory from both wild‐caught and laboratory‐reared triploid mothers. The relationship and significance of these triploid forms to the breeding complex of P. formosa and P. mexicana in nature are discussed.
The influence of activity level on bradycardia in trout (Salmo gairdneri) during hypoxia
Authors: Weintraub Matthew J.
Published: January 2006

Voltages associated with heartbeat were transmitted by radio from free‐swimming rainbow trout (Salmo gairdneri.) Variability in the bradycardia response associated with the hypoxic state was observed and appeared to be related to the normal activity state of the fish. Bradycardia as a physiological mechanism was discussed on the basis of this finding.
An acute septicaemic disease of brown trout (Salmo trutta) and Atlantic salmon (Salmo salar) caused by a Pasteurella‐like organism
Authors: Hårstein Tore , Bullock GrahamL.
Published: January 2006

Ulcerations of the skin associated with haemorrhagic petechiae of liver and kidneys, were the main signs of disease affecting salmon and brown trout in Norway. A death rate of 15–20% was estimated for the 5 month period of mid‐March‐August, although mortalities occurred throughout the year. Bacteriological examinations, involving 36 isolates, suggested the causual organism to be a Pasteurella although the DNA homology examination gave a G.C. ratio of 55.6 % which is high for Pasteurella as a group.
Defence mechanisms in fish
Authors: Ellis A. E. , Munroe A. L. S. , Roberts R. J.
Published: January 2006

The lympho‐reticular tissues in the plaice were investigated for their phagocytic properties on colloidal carbon after its intraperitoneal injection. Fish were killed at intervals ranging from 10 min to 25 days after injection. Although peritoneal macrophages constituted a large population of phagocytic cells, most of the carbon apparently gained access to the circulation as free particles and phagocytosis was performed predominantly by the ellipsoids of the spleen, the network of reticulo‐endothelial (RE) cells throughout the haemopoietic tissue of the kidney, and by the RE cells occupying intermuscular spaces in the atrium of the heart. The cardiac macrophages rapidly emigrated from the organ while the carbon containing macrophages in the kidney and spleen formed aggregates in the lymphoid areas, either within or outwith pre‐existing aggregates of melano‐macrophages.

The possible significance of phagocyte aggregations, including melano‐macrophages, in association with lymphoid elements in the kidney and spleen is discussed in the context of immune mechanisms.
Studies on ulcerative dermal necrosis of salmonids V. The histopathology of the condition in brown trout (Salmo trutta L.)
Authors: Roberts Ronald J. , Hill Barry J.
Published: January 2006

The clinical signs and histopathological findings of an ‘ulcerative dermal necrosis’ in brown trout were compared with those observed in salmon and sea trout suffering from UDN. There were close similarities in the lesions shown by both types of fish, but more brown trout recovered and the healing process was temperature dependent.
Leucocytes and related cells in the plaice Pleuronectes platessa
Authors: Ellis A. E.
Published: January 2006

The leucocytes and related cells of the blood of plaice were examined morphologically and their various functions assessed using a number of procedures to identify phagocytosis histochemical reactions and antibody responses. Four morphologically different types of thrombocytes were identified in addition to lymphocytes, plasma cells, monocytes, macrophages and one type of granulocyte which histochemically resembled the mammalian neutrophil. The evolution and development of the cells was also investigated and the various stages described.
The ovarian cycle of the cuckoo ray, Raja naevus (Müller and Henle), in the Celtic Sea
Authors: Du Buit Marie Henriette
Published: January 2006

One hundred female Raja naevus from the South Celtic Sea were examined every month for 14 consecutive months, for the characteristics of their ovarian cycle. Egg‐laying occupied more than half of the cycle. All females followed the same genital cycle but independently of each other. On the average 56% of adult females were at egg‐laying stage at any time throughout the year. Fecundity is estimated at 90 eggs a year.
Observations on meristic characters separating Pellonula afzeliusi Johnels, 1954 from Sierrathrissa leonensis Thys Van den Audernaerde, 1969
Authors: Otobo Fidelis O.
Published: January 2006

The meristic features of Pellonula afzeliusi and Sierrathrissa leonensis are compared to remove the confusion that has arisen over the identity of two clupeid species in West African freshwaters.

The discovery of a breeding population of S. leonensis in Kainji Lake confirms that it is correct to regard S. leonensis as a separate species and not the young of either Pellonula or Cynothrissa as was claimed by Roberts (1972).
The recapture of British salmon in Irish waters
Authors: Went A. E. J.
Published: January 2006

In the years 1972 to 1974, inclusive, a total of 50 salmon originally tagged as smolts in British rivers were recaptured in Irish waters. Although it is not possible to give precise reasons for these changes, some factors can be largely eliminated. The results do, however, indicate that salmon and grilse derived from British rivers occur in Irish inshore waters to a greater extent than was generally accepted.
Vibrio disease in eels
Authors: McCarthy D. H.
Published: January 2006

This is a first confirmed report of vibriosis or ‘red‐pest’ from wild eel (Anguilla anguilla) stocks in Great Britain. It is postulated that the epizootic was provoked by severe stress resulting from the abnormally high estuarine water temperatures and low freshwater flows present in affected rivers at the time. Bacteriological characteristics of the isolate, which was classified as a Vibrio sp., are described.
Aspects of the biology of the plerocercoid of Grillotia erinaceus (van Beneden, 1858) (Cestoda: Trypanorhyncha) in haddock Melanogrammus aeglefinus (L.)
Authors: Lubieniecki B.
Published: January 2006

From one to thirty Grillotia erinaceus plerocercoids were found in 3714 of 8228 haddock Melanogrammus aeglefinus caught in the northern North Sea, to the north and west of Scotland and at Faroe. Plerocercoids were also found in 30 of 64 cod from Aberdeen Bay, and in 44 of 55 saithe from the Firth of Clyde. In haddock, most plerocercoids occurred encysted along the intestine, and their frequency fitted a negative binomial distribution. Incidence and intensity of infestation increased with host age and there was no host sex difference in incidence. Three maturity stages were recognized, the proportions of which were consistent between haddock length groups. No precipitin bands developed in gel diffusion tests using live plerocercoids and sera from infested and uninfested haddock. Attempts to transfer plerocercoids between haddock were unsuccessful. Speculations are made on the possible course of the life‐cycle.
Size, growth, population density and food of brown trout Salmo trutta L. in two sections of a south Swedish stream
Authors: Otto Christian
Published: January 2006

Size, growth and population density of trout, Salmo trutta populations between the upper part of a small stream and downstream section were compared. The density of 0+ trout was about equal in the two sections, while trout >0+ were more numerous in the downstream section. Apart from water depth and volume, abiotic conditions were similar in the two sections. The utilization by trout of the available benthos was always greater in the downstream section. The discrepancies found in trout size and density between the sections were considered to be due to the increased spatial requirements by the larger fish. Growth rate of 0+ fish in terms of length increase per month was the same in both sections. The 0+ fish were found in the upper section. Earlier hatching due to temperature differences between the sections and larger size at hatching in the downstream section were factors of possible significance.
Body composition and organ weights of rainbow trout, Salmo gairdneri*
Authors: Denton Joan E. , Yousef M. K.
Published: January 2006

The objectives of the study were to determine the chemical constituents of rainbow trout (Salmo gairdneri) during the first 14 months of life, to study the effects of starvation on the body composition of trout, and to measure organ weights during the first 14 months of life.

Body fat and protein content as a percentage of body weight increased with age, the water content declined, and the ash content remained constant during the first 14 months of life. There were no significant differences in body composition between immature male and female rainbow trout. Total body ions as a proportion of ash content decreased until the 10th month and then began to increase. During starvation, fat was used as the primary source of energy while water and ash content increased and protein content remained constant as a percentage of body weight.

The gall bladder, liver, and air bladder remained relatively constant as a percentage of body weight during the first year of life. As body weight increased, the relative weight of brain, heart, and digestive system decreased while the gonad and spleen weight increased.
A preliminary report on the spawning behaviour and nature of sexual selection in the barbel, Barbus barbus (L.)
Authors: Hancock R. S. , Jones J. W. , Shaw R.
Published: January 2006

In the spring of 1974 the migration and spawning behaviour of barbel, Barbus barbus (L.) were observed. The migration and behaviour of males prior to the spawning attempts may be strategies designed to increase the quota of receptive females experienced by each male. Spawning attempts were divided into two categories: successful and failed. Successful attempts comprised six sequential sub‐events: approach period, pre‐spawning phase, spawning, post‐spawning phase, dispersal period and inter‐spawning period. The spawning and post‐spawning phases did not occur in a failed attempt. The success or failure of attempts was dependent upon the number of males present. The advantage gained by females abandoning attempts when the male densities were high is discussed. In both the pre‐spawning phase of failed attempts and the post‐spawning phase of successful attempts, males attempted to drive away other male competitors by the use of male ‘chase away’ interactions.
The downstream drifting of eggs of brown trout, Salmo trutta L.
Authors: Elliott J. M.
Published: January 2006

The occurrence of eggs in the drift samples was not related to fluctuations in flow rates, but was probably related to the presence of eggs in the gravel. Both the number (Y eggs 3h−1) and density (Y eggs 100−1 m−3) of eggs in the drift samples increased with increasing water velocity (Vm sec−1), and the relationship between the two variables was well described by the regression equation Y=a Vb where a and b are constants. Comparisons were made between two streams and different, years.
Some preliminary field observations of the burrows of the red band fish, Cepola rubescens L.
Authors: Atkinson R. J. A.
Published: January 2006

The burrows of the red band fish, Cepola rubescens L. were studied. They were located In sublittoral mud some 17m below C.D. off the coast of Lundy Island. The burrows were vertical to a depth of 60 cm, the same length as the fish, and had a diameter of 6–8 cm.
Population biology of parasites of striped mullet, Mugil cephalus L. I. Monogenea
Authors: Rawson Mac V.
Published: January 2006

Young‐of‐the‐year (class 0) and yearling (class 1) striped mullet, Mugil cephalus, were collected from Sapelo Island, Georgia from May 1970 to June 1971 to study the development, seasonal abundance and relationship of environmental variables to parasitic populations. The number of species of parasites increased with age of the host. Initial infection appeared to be influenced by closeness of association of mullet age classes, by the period of abundance of a parasite on class I mullet and by the mobility of the infective parasitic stage. Fluctuations in intensity and prevalence of a parasite on class 0 mullet were similar to those of class I mullet after the initial infection. Ancyrocephalus vanbenedenii was first observed on class 0 mullet in March. Intensity was high on both classes in spring and on reproductively active mullet in late autumn. Prevalence on both classes was above 80% except in late summer. Polyclithrum mugilis was not observed on class 0 mullet until August even though intensity and prevalence on class I mullet was highest during early spring. Gyrodactylus mugelus did not occur on class 0 mullet but appeared on class I mullet during late summer. Microcotyle psuedomugilis was observed on class 0 mullet in early summer and Metamicrocolyla maeracantha in October. Both species occurred but at a low intensity on class I mullet.
The length‐weight relationship, condition factor and gut contents of the dolphin‐fish Coryphaena hippurus (L.) in the Mediterranean
Authors: Bannister J. V.
Published: January 2006

The length‐weight relationship and condition factor of 420 dolphin‐fish (Coryphaena hippurus) collected in Malta in 1974 were determined. The length‐weight relationship for the size range investigated was similar to that reported for the fish from North America. The main food items were flying fish and other fish and crabs.
Electrophoretic analyses and denaturation tests of the haemoglobins of Trachurus trachurs (L.)
Authors: De Cristini F. , Graziosi G.
Published: January 2006

A total of 210 samples of haemoglobin of Trachurus trachurus (L.) caught in the Gulf of Trieste in 1972–1973, were analysed in search of haemoglobin polymorphism. Genetic polymorphism may be used as a genetic marker to identify sub–populations on the basis of allele frequencies.

All the samples analysed produced the same haemoglobinic pattern, composed of six bands. The quantitative differences noted between the various fractions were not sufficient to demonstrate the existence of different phenotypes.

Denaturation tests carried out by treating erythrocytes with non–sterile physiological solutions or by keeping the haemolysate at room temperature before electrophoresis, resulted in new patterns. This result shows the importance of the careful treatment of blood samples to assure reliable results.
The haemoglobins of the fish Sarotherodon mossambicus (Peters): functional significance and ontogenetic changes
Authors: Pérez Julio E. , Maclean Norman
Published: January 2006

The haemoglobin patterns of adult and young larval stages of the fish species Sarotherodon mossambicus were determined by polyacrylamide–gel electrophoresis. Oxygen affinity determinations of the adult and larval haemolysates and of each haemoglobin component of the adult indicates that the affinity changes with the pH, temperature and osmotic pressure. The possible evolutionary significance of the multiple haemoglobins is discussed. The electrophoretic pattern of adult S. leucostictus, a species closely related to S. mossambicus was also determined and used as a comparative study.
Electrophoretic identification of roach (Rutilus rutilus L.), rudd (Scardinim erythrophthalmus L.), bream (Abramis brama L.) and their natural hybrids
Authors: Brassington R. A. , Ferguson A.
Published: January 2006

Roach, rudd, bream and their natural hybrids of 2 cm standard length or larger can be definitively identified by their enzyme electrophoretic patterns. Zymograms of lactate dehydrogenase and esterases as produced by vertical starch gel electrophoretic analysis of whole fry or adult eye extracts are the most useful in this respect. The lactate dehydrogenase isozymes, containing B sub‐units, migrate more anodally in rudd and bream than in roach. Due to the tetrameric structure of lactate dehydrogenase, in hybrid rudd x roach and roach x bream, eleven isozymes can be observed as compared with six in the parental patterns. Esterases show unique patterns for all species and hybrids. With the exception of one fraction in rudd x bream, the esterase patterns of hybrids show summations of the parental phenotypes.
The population dynamics of young trout (Salmo trutta L.) in a Danish brook
Authors: Mortensen Erik
Published: January 2006

The population size, dispersal of fry, growth of fry in relation to density, mortality and production of young trout (Salmo trutta L.) were studied in a Danish brook during 1970–1972. In the first few months after emergence downstream emigration of fry took place both in 1971 and 1972, after which the trout became stationary. Growth was inversely density dependent and mortality was density dependent in the months just after emergence. Later mortality was constant and independent of density. Trout production varied between 10 g/m2 and 18.6 g/m2 in the 2 years.
Some aspects of the biology of the horse mackerel [Trachurus trachurus (L.)] in waters around Britain
Authors: Macer C. T.
Published: January 2006

Evidence is presented which supports the hypothesis of a seasonal migration between the North Sea and the western English Channel. Fish caught west of Britain have a different length composition and there is some evidence of a North–South migration. Analysis of stomach contents shows that the species is a plankton feeder. Data on seasonal growth in young fish show the growth‐rate is most rapid between August and December; length‐frequency distributions of two year‐classes were bimodal. The use of the otolith burning technique revealed up to 35 check rings, as compared with the reported maximum age of 10 years. With the exception of ring numbers 1 to 3, it could not be established the rings were annual.
The primary immune response of brown trout (Salmo trutta) to injection with cellular antigens
Authors: Ingram George A. , Alexander John B.
Published: January 2006

The primary immune response of brown trout (Salmo trutta L.) was studied after injections of two cellular antigens–Salmonella typhi H, flagellar antigen d, and human group ‘O’Rh+ red blood cells. Both intraperitoneal and intramuscular injections were employed. Agglutinins and complement–fixing antibodies were produced to S. typhi and haem–agglutinins to human ‘O’ red blood cells. Maximum titres to S. typhi were reached after 49 days in the case of both agglutinins and complement‐fixing antibody. Haem‐agglutinins reached a maximum value of 1 : 512 between 35 and 42 days. Haemagglutinins to human ‘O’ red blood cells were detected as early as 7 days after injection. Antibodies against S. typhi were found after 14 days. Natural haemolysins were present against horse, sheep and human groups ‘A’, ‘B’ and ‘AB’ but not with group ‘O’. No natural haemagglutinins were present to the six types of red blood cells tested. No precipitins were detected to either S. typhi or human ‘O’ red blood cells by immunodiffusion.
Effects of pinealectomy on pituitary gonadotrophs, pituitary gonadotropin potency and hypothalamic gonadotropin releasing activity in Notemigonus crysoleucas
Authors: de Vlaming Victor L. , Vodicnik Mary Jo
Published: January 2006

The effects of pinealectomy on pituitary gonadotrophs, pituitary gonadotropin potency and hypothalamic gonadotropin releasing activity were examined in the cyprinid teleost, Notemigonus crysoleucas, exposed to various photoperiod‐temperature regimes. In fish exposed to a long photoperiod‐warm temperature regime, pinealectomy resulted in a decrease in gonadal activity, in hypothalamic gonadotropin releasing activity and an increase in pituitary gonadotropin potency. Fewer gonadotrophs were present in the pituitary of sham operated fish than in the pituitary of pinealectomized fish. Ovarian development was more rapid in sham operated than in pinealectomized fish exposed to a long photoperiod–low temperature regime. Pituitary gonadotropin activity was also greater in shams than in pinealectomized fish. A short photoperiod‐warm temperature regime retarded ovarian development in N. crysoleucas. Pinealectomy reversed this trend. Gonadotrophs made up a greater area of the pituitary in pinealectomized fish than in shams under these conditions. Gonadotropin potency of the pituitary and hypothalamic gonadotropin releasing activity were also greater in pinealectomized fish than in shams. The area of the pituitary occupied by gonadotrophs was greater in pinealectomized than in sham operated animals maintained on a short photoperiod‐low temperature regime. Pituitary gonadotropin activity was also greater in pinealectomized fish as compared to shams. Pituitary gonadotropin potency varies diurnally in animals maintained on both short and long photoperiods; the rhythm of variation differs depending on photoperiod. Pinealectomy alters the diurnal rhythm of pituitary gonadotropin potency in animals exposed to both long and short photoperiods. It is concluded that pinealectomy has a pronounced effect on reproductive activity in N. crysoleucas. The effects of pinealectomy on reproduction vary with photoperiod, but are mediated via the hypothalamus and pituitary. In fish exposed to long daylengths the pineal favours reproductive activity, but the epiphysis retards reproductive processes in animals maintained on short photoperiods.
The biology and use of zebrafish, Brachydanio rerio in fisheries research.
Authors: Laale Hans W.
Published: January 2006

PREFACE TO THE REVIEW BY PROFESSOR H. LAALE ON THE BIOLOGY AND USE OF THE ZEBRAFISH, BRACHYDANIO RERIO IN FISHERIES RESEARCH

The growing demand for increasingly sophisticated information on the toxic hazards of potential water pollutants has focused attention on the need for a suitable ‘standard’ animal model which could be accepted internationally. The Zebrafish, Brachydanio rerio (Hamilton‐Buchanan, 1822, 1823) is considered to be the most likely candidate. It is relatively easy to maintain and breed in laboratory aquaria and it has proved to be responsive to a wide range of mutagens, carcinogens and teratogens, as well as direct toxicants. B. rerio has been the subject of a considerable number of investigations involving a diverse spectrum of disciplines in a number of countries. Professor Hans Laale, who has himself contributed to our knowledge of the embryopathology of B. rerio, has summarized and collated the findings of 450 publications, a number of which are unlikely to have become available to fishery scientists. We hope the publication of this review will aid those who are working with B. rerio and provide comprehensive data on the advantages and limitations of B. rerio as a contender for the standard laboratory fish for the safety evaluation of aquatic pollutants.

The Editor
Control of whirling disease (Myxosoma cerebralis): use of methylene blue staining as a possible indicator of effect of heat on spores
Authors: Hoffman Glenn L. , Markiw Maria E.
Published: January 2006

Methylene blue staining (0.08 %) was used to determine efficiency of heat treatment in killing spores of Myxosoma cerebralis. Nearly all spores heated at 90°C for 10 min and 70°C for 100 min became stained giving presumptive evidence that they were killed.
The histopathology of infection by Lepeophtheirus pectoralis (Müller) (Copepoda: Caligidae)
Authors: Boxshall G. A.
Published: January 2006

The histology of the pectoral fin of the flounder, Platichthys flesus. (L.), is described and the presence of eosinophilic granule cells in the epidermis was noted. The histopathological effects of infection by L. pectoralis result from the attachment and feeding activity of the parasite. Although the damage inflicted by L. pectoralis is usually confined to the epidermis the lesions caused by sessile life cycle stages, adult females and chalimus larvae, often extend into the dermis. In the dermis the inflammatory response comprised fibroplasia and cellular infiltration which resulted in the formation of a dense fibrous granulation tissue.
The development of catecholamines in embryos and larvae of the rainbow trout (Salmo gairdneri Rich.)
Authors: Meyer Wilfried , Sauerbier Ingrid
Published: January 2006

Catecholamines are present in the late embryonal and early larval developmental stages (alevin) of the rainbow trout. Changes in the alevin behaviour can be related to the catecholamine concentrations.
Food selection by young Catla catla (Hamilton–Buchanan) in a tropical fish pond
Authors: Jafri A. K. , Mustafa S.
Published: January 2006

Food selection by young Catla catla from a tropical fish pond was studied by computing the electivity indices for various types of planktonic food organisms. The fish was found to be a selective feeder. A positive selection was observed for cladocerans, copepods and nauplii larvae. Among the rotifers, however, Keratella and Brachionus were positively selected while Rotaria was completely avoided.

High electivity indices for some and low for the other genera were observed within each group of phytoplankton. Strict stenophagism seemed to occur for certain phytoplanktonic organisms.
D‐Amino acid oxidase in various fishes*
Authors: Fickeisen D. H. , Brown G. W.
Published: January 2006

A systematic procedure is provided for determination of D‐amino acid oxidase (EC 1.4.3.3) activity in fish tissues. Activity was surveyed in crude liver homogenates of twenty‐three species of fish. Activity ranged from 0‐047 to 3‐12 units (ρmol product produced per min) per gram wet weight of tissue. Activity was highest in liver, with significant levels occurring in kidney and pyloric caecae. It was below the limit of detection in brain, heart, spleen, testis, gill filaments, and muscle. Some properties of the enzyme from sockeye salmon, Oncorhynchus nerka (Walbaum), were studied. Knowledge of occurrence and levels of D‐amino acid oxidase in fish may be useful to fish aquaculturists contemplating supplementation of feed with racemic mixtures of amino acids.
Helminth and arthropod parasites of fishes in the mountain national parks of Canada
Authors: Mudry Dwight R. , Stewart Anderson R.
Published: January 2006

Sixteen parasite species including one monogenean, two digeneans, five cestodes, six nematodes. one acanthocephalan, and one copepod were collected from 257 fish of 13 species examined from 32 lake and nine stream sites in the mountain National Parks of British Columbia and Alberta. The following parasites are reported from Alberta for the first time: Bunodera luciopercae (Müller, 1776), Eubothrium rugosum Batsch 1786, Proteocephalus parallacticus MacLulich, 1943, Rhabdochona cascadilla Wigdor, 1918, Rhabdochona milleri Choquette, 1951, Contracaecum brachyurum (Ward & Magath, 1917), Bulbodacnitis truttae (Fabricius, 1794), Neochinorhynchus rutili (Mueller, 1780), and Ergasilus nerkae Roberts 1963. Tetraonchus variabilis Mizelle & Webb, 1953 and Rhabdochona milleri Choquette, 1951 are reported from British Columbia for the first time.
Oxygen requirements of embryos and larvae of the largemouth bass, Micropterus salmoides (Lacépède)
Authors: Spoor W. A.
Published: January 2006

Starting with the second day after fertilization, largemouth bass embryos and larvae became increasingly sensitive to oxygen deficiency until the sixth day of life. On this day few survived exposure to 1 mg O2/l for 3 h at 20°C; many were damaged at 2 mg/1, but not at 2.5. Death was by asphyxiation or by starvation resulting from an apparent inability to close the lower jaw. On the seventh day the larvae became more resistant again, possibly because opercular movement began on that day. At 25°C the effects of reduced oxygen concentration were intensified, and even a concentration of 2.5 mg/1 became lethal in 3 h. At 3 mg O2/l and 20° the normally quiescent yolk‐sac larvae became very active and swam vertically to at least 5 or 6 cm above the substrate; 4 and 5 mg/1 had this effect at 23–24°. This behaviour could result in losses by predation and displacement from the nest.
The relationship between changes in condition and body composition in young Tilapia rendalli Boulenger
Authors: Caulton M. S. , Bursell E.
Published: January 2006

Good correlations exist between condition and the amount of fat, protein and water present in young Tilapia rendalli, but extreme care must be exercised when determining the nature of these relationships. The use of percentages when expressing the amounts of each component should be avoided because such analyses can lead to erroneous results. Similarly the often used fat‐water relationship for predicting the fat content in fish should not be used as this also leads to erroneous results. The reasons for the poor relationships are discussed and methods for overcoming these problems are given.
Effect of ration level on nitrogen excretion, nitrogen retention and efficiency of nitrogen utilization for growth in largemouth bass (Micropterus salmoides)
Authors: Savitz J. , Albanese Elizabeth , Jean Evinger Mary , Kolasinski Pamela
Published: January 2006

Largemouth bass (Micropterus salmoides) with an average weight of 45.5 g were used to study ration level effects on nitrogen excretion, nitrogen retention, and gross efficiency of utilization of nitrogen for growth. Bass were starved 3 to 4 days and then each bass was placed into an aquarium containing a known volume of water. One day after the fishes were placed in aquaria, nitrogen excretion rates were determined; this rate is the maintenance nitrogen excretion. Each fish was then fed one or more shiners (Notropis cornutus); fish were fed only once. Nitrogen excretion measurements were made daily until the rates were similar to maintenance rates. The nitrogen excretion rates for each day after feeding which were above the maintenance nitrogen excretion were combined and reflect the total nitrogen excretion for a given ration level. All ration levels were converted to nitrogen consumption in mg and nitrogen absorption was calculated from subtracting the average faecal nitrogen from nitrogen consumption. From data on nitrogen consumption, nitrogen absorption, nitrogen excretion, and faecal nitrogen, calculations were made for nitrogen retention and gross efficiency of utilization of nitrogen for growth.

As ration level and nitrogen absorption increased, nitrogen excretion increased and is described by the equation, Y= 8.56+0.40 X, where Y is total nitrogen excretion and X is nitrogen absorption. Nitrogen retention also increased with nitrogen absorption and is described by the equation, Y=–8.57+0.60 X, where Y is nitrogen retention and X is nitrogen absorption. Efficiency increases rapidly above maintenance, but levels off at higher ration levels and approaches an asymptote of 60%.
The migration of elvers of Anguilla anguilla L. in the Mex canal, Alexandria, Egypt
Authors: Ezzat A. , El‐Serafy S.
Published: January 2006

The run of elvers of Anguilla anguilla (L) up the Mex canal, Alexandria, Egypt, starts at the end of February and continues until June, with the main bulk of elvers arriving in April and May. Variations in the timing of this run may be attributable to variations in local ecological conditions. The run is affected by meteorological and hydrographic factors. The effects of the latter have been assessed, and a low oxygen content, a pH between 7.7 and 8.0, a chloride content between 2.1 and 2.3 Cl/1 and a temperature between 20 and 25°C have been found to encourage large numbers of elvers to migrate up the fresh water canal. In contrast to previous findings, the results of this study suggest that the mean length of elvers running increases towards the end of the season.
Preliminary studies on the conversion of Tubifex tubifex as food by elvers of Anguilla nebulosa (Gray and Hardwicke)
Authors: Ravichandra Reddy S. , Shakuntala Katre , Rajagopal K. V.
Published: January 2006

Elvers of Anguilla nebulosa were reared at 23°C in confined waters and their food intake, growth and conversion efficiency (K1:%) were studied. Elvers weighing 278.33±14.35 mg were fed on an ad libitum diet of the oligochaete worm Tubifex tubifex for 60 days. On an average, the test individuals consumed 99.55±19.81 mg food/elver/day amounting to 35.76% of the initial biomass; during the corresponding period the elvers exhibited a growth rate of 5.03±2.42 mg gain in weight/elver/day which is equivalent to 5.06% of the consumed food. Thus the ‘housekeeping’ of these elvers may be regarded as established. In 50 days, the food required amounts to 0.358±50 = 17.90 times the initially stocked biomass. That is, 1 kg of initially stocked elvers may need 17.90 kg of T. tubifex to produce 0.912 kg of elver meat. A poor conversion ratio of 20 : 1 may be one reason for the slow growth of the elvers.
Salinity tolerance of Gambusia affinis (Baird & Girard) and Heteropneustes fossilis (Bloch)
Authors: Al‐Daham Najim K. , Bhatti M. Nazir
Published: January 2006

The present paper describes the results of a study on the salinity tolerance of two freshwater fishes, Gambusia affinis (Baird & Girard) and Heteropneustes fossilis (Bloch). The two species were treated with various concentrations of sea water and three most common salts found in the saline waters of Iraq, namely sodium chloride, calcium chloride and potassium chloride. The mortality rates following these treatments were recorded. Both species showed the highest degree of resistance for sea water and sodium chloride, and the lowest degree of tolerance to potassium chloride. Gambusia affinis was more resistant to these salts and sea water than H. fossilis.
A study of the conversion of cholesterol to bile acids by the use of a fistulated bile duct
Authors: Kallner Anders
Published: January 2006

A method for the surgical preparation of a bile fistula in the sculpin Myoxocephalus quadricornis is presented. This model was used in demonstrating the conversion of 14C‐cholesterol into bile acids. The main acid metabolite was cholic acid and the presence of dihydroxy bile acids was also demonstrated. The amount of labelled compounds which was recovered in the bile was small both in case of parenteral administration to fistulated sculpins and after peroral administration to intact animals. This may be attributable to slow metabolism at the low ambient temperature these animals require to survive.
A review of chemical communication in freshwater fish
Authors: Solomon D. J.
Published: January 2006

Since communication between individuals of a species of fish by chemical agents (pheromones) was first demonstrated in 1932, such a process has been suggested in many aspects of fish behavidïo'ur and development. This review describes observations on such mechanisms in shoaling behaviour and beneficial conditioning of water, homing of migratory fish, communication of alarm, ‘crowding factor’ (which adversely affects growth, survival and fecundity in dense populations), pair formation and spawning, and a range of other social interactions. Some of the chemicals involved have been isolated and identified, but most are indicated by behavioural observations. Pheromones are of great significance in fish behaviour and ecology, and are likely to be an important factor in culture operations.
The food of Charr,*Salvelinus willughbii (Günther), in Windermere
Authors: Frost Winifred E.
Published: January 2006

The stomach contents of 1015 charr, (Salvelinus willughbii Günther)] from Windermere, of which 658 were feeding fish, were examined. The fish were caught over a period of several years and in every month of the year. The data were analysed by two methods, by a points system, which takes into account the abundance and volume of the food organisms, and by the frequency of occurrence of each organism. Charr of all sizes had fed mainly on planktonic Crustacea (particularly Cladocera); larval and pupal chironomids and Chaoborus were also important. From November to April most stomachs of charr netted on the spawning grounds contained charr eggs. The diet of charr is compared with that of seven other fish species in Windermere. There was almost no overlap between the food of charr, which was obtained in the pelagic region, and that of the seven other species, which was mostly bottom fauna, obtained from the littoral region. Thus by occupation of these two different niches the charr and the seven other fish in no way compete for food in Windermere. Some limited data from six other lakes in the English Lake District are presented, in these planktonic Crustacea are also found to be the main food.
A comparative study of glycolysis in red and white muscles of the trout (Salmo gairdneri) and mirror carp (Cyprinus carpio)
Authors: Johnston Ian A.
Published: January 2006

The activities of some glycolytic and associated enzymes have been determined in the muscles of trout and carp to investigate the possibility that the discrepancies previously reported between lactate accumulation and anoxic tolerance in these two fish result from underlying differences in glycolytic potential. Steady state concentrations of certain glycolytic intermediates were also determined in freeze‐clamped muscles from tankrested fish. The activities of hexokinase, phosphorylase and phosphofructokinase were approximately 2–3 times lower in carp than trout white muscles. Pyruvate kinase and lactate dehydrogenase activities were 5 times lower in carp white muscle. The lower, broader pH optima of lactate dehydrogenase and pyruvate kinase from carp compared to trout muscles is thought to be correlated with the greater anoxic tolerance of the carp. Glycolytic enzyme profiles were markedly different between the red and white muscles of the rainbow trout but broadly similar, with the exception of hexokinase activity, for the corresponding muscles of the carp. The results are discussed in relation to what is known about anaerobiosis in these two species and the comparative physiology of red and white muscles in fish.
The population biology of two species of eyefluke, Diplostomum gasterostei and Tylodelphys clavata, in perch
Authors: Kennedy C. R. , Burrough R.
Published: January 2006

Incidence, intensity and frequency distributions of infections in perch, Perca fluviatilis, with the eyeflukes Tylodelphys clavata and Diplostomum gasterostei were studied in a lake at monthly intervals over a period of two years. T. clavata had appeared in the lake immediately prior to the study, and its levels of infection continued to rise throughout the period of investigation whereas those of D. gasterostei remained relatively steady. The main period of infection of fish by both species of parasites was late summer, but a second and minor infection took place in spring. In the first year after its introduction T. clavata exhibited a seasonal cycle in incidence and intensity of infection and disappeared from fish in summer, but in the second year this cycle was masked by increased variation in development times and lack of synchrony throughout the parasite population. It is concluded that T. clavata has a life span of one year or less and that the parasites die within the fish, mainly in summer. D. gasterostei in contrast has a life span of at least one year, and disappearance of the parasite from the population is probably due to death of some heavily infected fish, although it was not possible to determine if this was due directly to the presence of the parasite.
Characteristics of the freshwater occurrence of sea trout Salmo trutta in Ireland
Authors: Fahy Edward
Published: January 2006

Information is provided on the distribution of sea‐trout in Ireland. Records come from 158 catchments. The characteristics of these catchments are considered in relation to the biology of the fish.
Protein concentration in the serum of the Atlantic salmon (Salmo salar) in North‐west England and Northern Ireland
Authors: Alexander J. B.
Published: January 2006

The protein concentration of the serum of the Atlantic salmon was measured in samples collected from North‐west England in the years 1967–1975. During this time, the mean protein concentration (g 100ml–1) increased from 3.05–7.77 in males and from 1.93–5.72 in females. Whilst a straight line could be fitted to the results, there was the possibility of a three year cycle in the protein concentration. The cycle occurred simultaneously in both males and females. In marine and estuarine fish from Northern Ireland the protein concentration was about twice that in the comparable freshwater group from North‐west England.
Variation in some biological characteristics of British sea trout, Salmo trutta L.
Authors: Fahy E.
Published: January 2006

Almost 50 assessments of British sea trout are available in the literature and the objective in this work is to examine variation in the parameters by which the fish are usually described and to discover biological criteria on which stocks may be classified. Eight statistics are common to the majority of stock evaluations: mean smolt age, proportion of finnock to spawn, mean age of a stock at first maturation, size achieved by the smolt at migration, rate of growth at sea, survival at sea, diversity of age categories in a stock and condition factor of sea‐run fish. When the influence of each factor on the others is tested two characteristics emerge as being of key importance in the biology of adult sea‐trout; the life expectancy and the weight: percentage previous spawners in a sample. The distribution of stocks is discussed in this context and two main groupings of British sea trout, corresponding geographically with the Irish sea and the Atlantic sea‐board, are proposed.