bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in the population of polyribosomal containing red cells of peripheral blood of rainbow trout, Salmo gairdneri Richardson, following starvation and bleeding
Authors: Lane H. C. , Tharp T. P.
Published: January 2006

Peripheral blood of trout contained two populations of red cells: those with polyribosomes located in the cytoplasm, and those without polyribosomes. Starvation of trout for 30 days was accompanied by a proportional decline of the polyribosomal‐containing (PRC) red cells. One week after a 15% bleeding of both fed and starved animals fed individuals showed a proportional decline of PRC red cells whilst starved fish showed a proportional increase of the same cell population. In fed individuals the bleeding response was accompanied by the appearance of many red cells with senescence‐related characteristics. PRC cells in both groups of animals were arbitrarily subdivided into three subgroups according to the density of polyribosomes present. No statistically demonstrable differences were evident between the means of the three PRC cell groups of control animals and those subjected to starvation and bleeding. However, there was an apparent rise in the proportion of red cells with the highest density of polyribosomes as a result of both treatments.
Protection of channel catfish, Ictalurus punctatus Rafmesque, against Ichthyophthirius multifiliis Fouquet by immunization
Authors: Goven B. A. , Dawe D. L. , Gratzek J. B.
Published: January 2006

Channel catfish, Ictalurus punctatus Rafmesque, were immunized with ciliary and whole cell preparations of Ichthyophthirius multifiliis and subsequently challenged with I. multi‐filiis. Similar Telrahymena pyriformis preparations were used to determine if this heterologous immunization would elicit a protective immune response against I. mullifiliis infestation. Results indicate that T. pyriformis ciliary antigens provided the greatest degree of protection.
A biochemical genetic analysis of populations of the northern pike, Esox lucius L., from Europe and North America
Authors: Healy J. A. , Mulcahy M. F.
Published: January 2006

Genetic variation as identified by starch gel electrophoresis and enzyme staining was studied in seven populations of the northern pike, Esox lucius L. Samples derived from populations in northern U.S., Canada, Swedish fresh water, Swedish Baltic, the Netherlands, England and Ireland were analysed for variation at between 10 and 26 enzyme‐coding loci. Polymorphism was found to be restricted to three loci: Sod‐1 (mitochondrial superoxide dismutase), Ldh‐2 (heart‐type lactate dehydrogenase) and Got‐1 (cytoplasmic glutamateoxalate transaminase). Mean heterozygosity (H) over all seven population samples was estimated to be 0·019. This extremely low variability, relative to reported data for other fish species, is discussed in terms of the structure and possible origins of pike populations.
Effects of starvation on proximate chemical composition and energy utilization of plaice, Pleuronectes platessa L.
Authors: Jobling M.
Published: January 2006

Proximate analysis of the body tissues of plaice showed that body fat was the major storage reserve utilized during starvation. Although the liver and gut were much depleted during the period of the fast they contributed only a small proportion of the metabolizable energy. Atrophy of the gut led to reductions in motor activity but the ability to digest and absorb nutrients was not impaired. Assessments of energy utilization using proximate analysis and calculations from ammonia quotient determinations are compared and show that during the latter part of the fast 20–25% of the energy utilized was derived from protein catabolism.
Adoptive transfer of immunity against Vibrio anguillarum in rainbow trout, Salmo gairdneri Richardson, vaccinated by the immersion method
Authors: Vlele D. , Kerstetter T. H. , Sullivan J.
Published: January 2006

Rainbow trout, immunized by the immersion method against Vibrio anguillarum, were used as donors of plasma and cells for transfer to unimmunized trout. Recipients were then challenged with a 20 min exposure to a virulent Vibrio anguillarum suspension, and the mortality was compared to that of trout receiving plasma and cells from unimmunized donors. Immunity was successfully conferred by plasma taken from immune donors 16 days post‐immunization (PI), and by pronephros and spleen cells from Day 20 and 21 PI donors. Plasma was most effective in transferring vibriosis protection, followed by pronephros cells. Splenocytes gave variable results, while trials with thymus cells were negative in all cases.
Scanning electron microscopic study of the gut mucosa of the rainbow trout Salmo gairdneri Richardson.
Authors: Ezeasor Daniel N. , Stokoe W. M.
Published: January 2006

The topological characteristics of the entire gut surface of the rainbow trout were investigated utilizing the scanning electron microscope. The mucosa exhibited longitudinal ridges in the oesophagus and stomach, villi in the intestine, fine longitudinal ridges in the caeca and annular folds in the rectum, arranged as a stack of caudally‐directed funnels starting from the intestino‐rectal valve to the vent. Detailed study revealed taste pores in the anterior oesophagus and the sculpting of the luminal plasmalemma of the surface cells into micro‐ridges with complicated patterns. The surfaces of the posterior oesophagus and stomach were demarcated into polygons by rows of stubby microvilli—each polygon representing the luminal surface of an epithelial cell. Each rectal fold consisted of a smooth, caudally‐directed apex and a base which was supported by perpendicular buttress‐like secondary folds. The functional significance of these features which emphasize the vast difference in the physical length of the gut and the effective surface area is discussed.
Seasonal variations in sex steroids of female rainbow trout (Salmo gairdneri Richardson)
Authors: Scott A. P. , Bye V. J. , Baynes S. M.
Published: January 2006

17β‐oestradiol, testosterone, 11 ‐ketotestosterone and calcium were measured in plasma of female rainbow trout over the course of a single spawning season. The patterns of rise and fall of the levels of 17β‐oestradiol and calcium during sexual maturation were similar to those demonstrated by other workers. Very high levels of testosterone were found in plasma of sexually mature fish—mean level 211 ng ml‐1 in November and 115 ng ml‐1 in January. Ovulation occurred from December to February.
Some physiological consequences of angling stress in muskellunge, Esox masquinongy Mitchill
Authors: Beggs G. L. , Holeton G. F. , Grossman E. J.
Published: January 2006

Capture of muskellunge by angling resulted in a reduction of blood pH, elevated lactic acid concentrations, and a drop in total carbon dioxide and bicarbonate concentrations. The acidaemia was most severe immediately after capture and began to decline well before the blood lactate levels rose. Blood lactate levels were not as high as those characterizing fatigue in most other species. Recovery from the acidosis required 12 to 18 h and was accompanied by declines of 22% and 40% in haemoglobin and haematocrit levels respectively. With the exception of dying fish, there were only slight fluctuations in plasma sodium and potassium levels during recovery, indicating that there was no severe ionoregulatory dysfunction.

Thirty per cent of all angled muskellunge died. The last stages immediately preceding death were characterized by declining blood pH and elevated potassium levels.
Effects of sedimentation on the gravels of an industrial river system
Authors: Turnpenny A. W. H. , Williams R.
Published: January 2006

The natural recovery of trout (Salmo trutta L.) populations in an industrial river, the Ebbw Fawr, South Wales, has been depressed by problems of natural recruitment. Rainbow trout (Salmo gairdneri Richardson) eggs were planted in river gravels to assess the effects of siltation on salmonid spawning success. In reaches where siltation due to the coal industry has occurred, 98–100% of eggs died during incubation in the gravels. Experiments using standpipe techniques measured gravel permeabilities and rates of dissolved oxygen (DO) supply to artificially planted eggs, the results showed a strong dependence of hatching success and alevin size on these two parameters. The median lethal DO supply rate was about 50 μg cm‐2 h‐1.
Substances involved in the natural resistance of fish to infection–A review
Authors: Ingram G. A.
Published: January 2006

Natural‘antibodies’are substances found in the blood of animals that have not been immunised against infective agents. However, exposure to these agents or to cross‐reacting antigens may well have taken place. Fish contain naturally‐occurring, relatively nonspecific, lectin‐like proteins or glycoproteins, which are distinct from immunoglobulins, and which react with a wide variety of antigens and may confer some degree of immunity against natural infection. In most cases the cause of the antigenic stimulus is not obvious although the formation of these‘antibodies’may have been brought about by exposure to various micro‐organisms. Many of these antibody‐like molecules behave in a similar manner to immune antibodies or immunoglobulins and cross‐react with specific carbohydrate moieties on the cell walls of bacteria, erythrocytes and certain other cellular antigens, due to the presence of similar antigenic determinants.

It is difficult to ascribe an appropriate definition to the term‘natural antibody’. In fish, these‘antibodies’have been so designated on the basis of functional rather than structural criteria. Such naturally‐occurring, low grade, antibody‐like‘immune’substances include‘acute phase’proteins, lysozyme and chitinase, interferon, agglutinins, lysins, complement and properdin, precipitins, and non‐immunoglobulin, lectin‐like molecules. In addition to the above non‐immunoglobulin materials, natural immunoglobulins identifiable as IgM have also been reported in fish. Furthermore, mucus contains many biochemical agents capable of reaction against infective organisms and thus providing the host with an immediate or a first line of defence mechanism.

This review compiles some of the relevant information in the literature concerned with natural‘immune’substances, present in the serum and mucus of fish, involved in protection against pathogens. Wherever possible the basic physicochemical properties of these substances are indicated and their potential immunobiological functions discussed.
The effects of three different dietary protein levels on the fecundity in the guppy, Poecilia reticulata (Peters)
Authors: Dahlgren B. T.
Published: January 2006

Experiments were performed to investigate the influences of dietary protein on fecundity in the guppy, Poecilia reticulata. No significant differences in total body length and standard length were found between females given food with different protein levels. A significantly higher total body weight was found both in females fed on 47% and 31% protein compared with females given 15% protein. The frequencies of females with only intrafollicular embryos or with only ova or both embryos and ova in the ovary were not significantly different between populations given different protein amounts. There was a significantly lower frequency of females without embryos and ova but with previtellogenic oocytes in the group given highest protein (47%) compared with the group fed on 31%. Significantly higher values of ovarian length, width and gonad weight were found among females given 47% protein compared with females fed on 15% protein. The ovarian height was significantly higher only in females given the highest protein amount when compared with the group fed on 31% protein. No significant difference of ovarian volume was found between groups given different protein contents. The average gonadosomatic ratio was highest in the groups fed on 47% protein. Significant correlations were found between gonad weight and total body weight of females in each group. Ovarian volume versus total body weight as well as versus gonad weight also yielded significant correlations in all groups. No significant differences of fecundity were found either between females given 47% and 31% protein or between females fed on 47% and 15% protein. A somewhat higher number of ova per individual fish was, however, observed among females given 31% when compared with females fed on 15% protein. The ovum size remained the same between groups given different protein contents. No significant correlation was found between fecundity and ovum diameter in the groups.
The effects of acclimation on the salinity tolerance of grass carp, Ctenopharyngodon idella (Cuv. and Val.)
Authors: Kilambi R. V. , Zdinak A.
Published: January 2006

Grass carp acclimated to 3, 5, 7, and 9% salinities were tested for salinity tolerance. The upper tolerance limit (LS50) for 3 and 5%, and 7% acclimated fish were 14.2 and 14.0%, respectively. Fish acclimated to 9% had a 50% mortality at an estimated salinity of 16.0%, for 24 h exposure. Weight losses for the 3 and 5% acclimated fish were significantly lower than for those acclimated to 9%.
The food of five gadoid species during the pelagic O‐group phase in the northern North Sea
Authors: Robb A. P. , Hislop J. R. G.
Published: January 2006

The diets of five gadoid species in the northern North Sea are described: the cod, Gadus morhua (L.); haddock, Melanogrammus aeglefinus (L.); whiting, Merlangius merlangus (L.); saithe, Pollachius virens (L.); and the Norway pout, Trisopterus esmarkii (L.). The diet of each species was shown to be a gradual progression to different prey species as the predators increased in length. There were differences in the food taken by each species with respect to numbers, species and size. These differences in diet suggest that the degree of competition between pelagic O‐group gadoids is not great.
Social hierarchy in relation to adrenocortical activity in Xiphophorus helleri Heckel
Authors: Scott D. B. C. , Currie C. E.
Published: January 2006

A study of the epideictic behaviour patterns of male Xiphophorus helleri Heckel was made, and the social rank of individual fish in 12 groups of three was assessed over a ten‐day period. Straight‐line hierarchies were established in most groups. An anatomical study was made to locate the adrenocortical tissue, and the adrenocortical activity of each fish was assessed by measuring mean nuclear diameter of 25 adrenocortical cells. Although results were somewhat variable, the highest‐ranking fish in 7 out of 12 groups showed the least adrenocortical activity. The remaining two fish showed no significant difference from each other in adrenocortical activity, though their rank was in most cases clearly distinguishable on behavioural grounds.
Swimming performance of European eel (Anguilla anguilla (L.)) elvers
Authors: McCleave J. D.
Published: January 2006

To determine the relation between swimming endurance time and burst swimming speed, elvers of the European eel, Anguilla anguilla (L.), were made to swim at speeds from 3.6 to 7.2 L (body lengths) s−1 in both fresh and sea water. Swimming endurance time of elvers averaging 7.2 cm total length decreased logarithmically with increased swimming speed from 3.0 min at 3.5 L s−1 to 0.7 min at 5.0 L s−1, and again logarithmically but with a lesser slope to 0.27 min at 7.5 L s−1. No differences were found between fresh and sea water elvers. In still water, elvers could swim at high speeds for about 10–45m before exhaustion, depending upon speed. Elvers would be able to make virtually no progress against water currents >50 cm s−1. Drift in coastal water currents and selective tidal transport probably involve swimming speeds below those tested in this study. Migration into freshwater streams undoubtedly involves avoidance of free stream speeds and a combination of burst and sustained swimming.
Ultrastructure of a Haplosporean‐like organism: the possible causative agent of proliferative kidney disease in rainbow trout
Authors: Seagrave C. P. , Bucke D. , Alderman D. J.
Published: January 2006

The protozoan parasite which has been suggested as the causative agent of proliferative kidney disease in rainbow trout has previously been described as an‘amoeba’. However, this ultra‐structural study of the organism (named‘PKX’) has demonstrated many similarities to a group of invertebrate parasites, the genus Marleilia (currently classified in the Haplosporea). The suggested affinity of PKX‘ to Marteilia is based on the presence of internal cleavage,‘haplosporosomes’, and an amorphous cell wall. Other cytoplasmic inclusions also show characteristics of the genus. Since a spore stage has not been recognised in ‘PKX’, a definitive taxonomic statement cannot yet be made.
Quantitative seasonal changes in the protein, lipid and energy content of the carcass, ovaries and liver of adult female plaice, Pleuronectes platessa L.
Authors: Dawson A. S. , Grimm A. S.
Published: January 2006

A detailed study was made of the seasonal changes in energy reserves in adult female plaice, Pleuronectes platessa L. The weights of lipid, protein, glycogen and ash in the carcass, liver and ovaries were measured in females approximately 35 cm long on ten occasions during one year. These data were converted to data for a‘real’growing female by using a growth curve to take account of increasing length during the year. Growth of the whole body and of the body components was assumed to be isometric.

Plaice show a marked seasonal cycle of body weight and energy content. A six year old female plaice of 330 g, 32.6 cm long and with an energy content of 406 kcal in May, assimilates 560 kcal before December when it ceases to feed. Of this, 234 kcal is used to produce eggs, 159 kcal is used for metabolism during starvation, and the remainder 167 kcal, is used in growth. There is an increase in length to 35.9 cm and in weight to 462 g over the year. From December until March, when plaice do not feed but grow large ovaries, 40% of the protein in the body is utilised, 33% is devoted to egg production and 7% is metabolised to provide energy; 64% of the lipid is used, only 14% being used for egg production but 50% is metabolised for energy. Lipid supplies 75% of the energy for metabolism and so forms the major reserve; 42% of the energy assimilated during the year is devoted to reproduction. The main source of lipid and protein reserves is the carcass.
Survival and growth of salmon, Salmo salar (L.), planted in a Scottish stream
Authors: Egglishaw H. J. , Shackley P. E.
Published: January 2006

Salmon eggs and unfed fry were planted in reaches (total length 2.8 km, mean width 4 m) of a Scottish stream between 1971 and 1977 and their subsequent progress was studied by sampling 16 sections (areas 38–126 m2) of the stream. Brown trout are the only fish which spawn in the stream, waterfalls and a dam near its mouth preventing adult salmon and sea‐trout passing upstream. There were no restraints on the downstream movement of fish except in 1977, when a fry trap was operated. In 1971 and 1974 boxes each containing 300 eggs were buried in groups of 3–6. In other years fry were evenly distributed at 3.6–29.3 m−2. At the end of the first growing season, salmon occurred at decreasing population densities for a distance of 600 m below the plantings, but after two growing seasons there was little remaining indication of their pattern of dispersion when planted. Rates of survival between planting and the end of the growing season were 9.4–31%. Survival when eggs were planted (11.1–14.8%) was not affected by the numbers planted together at one point (900–1800) or the distance apart of groups of boxes (10–85 m). When fry were planted the instantaneous mortality rate (M) of the 0+ salmon during their first growing season was related to the initial stocking density (Dp) by the formula M= 0.00637 + 0.00444 log10Dp. Twenty‐two to 88% of 0+ salmon present at the end of the growing season were still surviving in the stream as 1+ fish one year later. In 1973–1976 only a small number of 2+ salmon occurred, the majority having migrated between the end of the second growing season and the following spring. There were more 2+ salmon in 1977 and 1978 resulting from higher stocking densities in 1975 and 1976 and slower growth. Trout of several age classes were present but their population densities were never high (<0.6 m−2). Salmon reached a greater size than trout by the end of the first growing season. Their mean weight (Wo, g) at this time was inversely related to their population density (Do No. m−2) and the biomass (B1, g m−2) of 1+ salmon present, giving the relationship log10wo= 0.6584–0.0558 D0‐0.0352B1. The mean weight of 1+ salmon tended to be highest in sections where the 0+ salmon had reached a relatively large size the previous year. When a reach of the stream was planted twice (11 and 30 May 1977) with salmon fry (total 13.9 m−2) at the same stage of development, M during the first growing season was 0.0099 per day. This was less than that of fry in a control (M= 0.0107) where the stocking density was lower (6.8 m−2) and also less than in previous years when single planting rates of approximately 14 m−2 were used (M=0.0115). The double planting resulted in a wide range of lengths of 0+ salmon in September and the highest biomass values encountered during all experiments.
Changes in minnow, Pimephales promelas Rafinesque, schooling behaviour associated with infections of brainencysted larvae of the fluke, Ornithodiplostomum ptychocheilus
Authors: Radabaugh D. C.
Published: January 2006

The schooling behaviour of unparasitized fathead minnows, Pimephales promelus Rafinesque, was compared to that of minnows infected with brain‐dwelling metacercariae of the fluke, Ornithodiplostomum ptychocheilus (Faust). Laboratory results showed that schools of infected fish divided more frequently, were less compact, and occupied positions closer to the water surface than control schools. These results are discussed with reference to the possibility that this larval parasite manipulates minnow behaviour to increase host vulnerability to predation.
Morphometric examination of the gills of walleye, Stizostedion vitreum vitreum (Mitchill) and rainbow trout, Salmo gairdneri Richardson
Authors: Niimi A. J. , Morgan S. L.
Published: January 2006

Observations on the gill morphology of individual gill arches of walleye, Stizostedion vitreum vitreum and rainbow trout, Salmo gairdneri suggest that the first two arches account for the highest proportion of gill filament number, secondary lamellae number, lamellae area, and gill surface area. Interspecific comparisons suggest walleye contain a larger number of gill filaments, with a lower secondary lamellae count, but a larger gill surface area than a trout of the same weight. This is partially attributed to the larger surface area of each lamella in a walleye than in a trout.

A detailed examination suggests the surface area of a lamella is dependent on its position on the gill filament, and the position of the gill filament on the gill arch.
The fishes of Saint Paul's Rocks
Authors: Lubbock R. , Edwards A.
Published: January 2006

Fifty species of fishes are recorded from Saint Paul's Rocks in a checklist which includes notes on ecology and behaviour. The poor species diversity, which is the lowest of any tropical island studied to date, seems to result from the isolation of the Rocks and also their small size and lack of habitat diversity. Large pelagic and semi‐pelagic predators, especially Galapagos sharks, are unusually common; 12.1% of identified shore fishes at St Paul's appear to be endemic to the Rocks, while 6.1% are known only from the tropical islands of the mid‐Atlantic ridge (St Paul's, Ascension, St Helena); 15.2% are recorded only from Brazil and St Paul's 30.3% are widespread western Atlantic forms that have the central Atlantic as the eastern limit of their range; a further 36.4% are widely distributed throughout the tropical Atlantic. Three new species are described: Anthias salmopunctatus, Stegastes sanctipauli and Enneanectes smithi.
Recovery growth following periods of restricted rations and starvation in rainbow trout Salmo gairdneri Richardson
Authors: Weatherley A. H. , Gill H. S.
Published: January 2006

Fingerling rainbow trout (6.9 to 11.6 cm fork length) maintained at 12° C were either: fed restricted rations (3% of dry body weight/day) for 16 weeks, or starved for 3 weeks (14.5% weight loss), or for 13 weeks (32.5% weight loss). Whole body wet weights and dry weights (as % of wet weight), and wet and dry weights of tissues (heart, spleen, liver, skin, gonad, gut, visceral fat, and ‘carcase’) resulting from these treatments were compared to corresponding weights of an ‘initial sample’. Visceral fat was completely utilized during both short and long‐term starvation and gut was significantly reduced in the extended starvation group.

During subsequent recovery growth on full rations, following food deprivation, fish grew at approximately the same rate as fully‐fed controls, which had not suffered food deprivation, as regards body wet weight and condition (K), but tended to surpass controls in % dry weight.

Heart, liver, gonad, gut and visceral fat also increased during recovery growth in a manner suggestive of overcompensation in response to former food deprivation. Gut, skin and carcase dry weights were less in the control, and in the 14.5% weight loss groups following recovery growth than in those in 3% rations and in the severely starved group, indicating that the effects of slow growth resulting from limited rations resemble those of severe starvation more than those of limited starvation.
Oxygen consumption in the fry of brown trout (Salmo trutta L.) related to pH of the water
Authors: Carrick T. R.
Published: January 2006

Fry were reared in Windermere lakewater at pH 7.0 or acidified to pH 4.5–5.0. Oxygen uptake by 0.1–5.0 g fry was compared at pH 7.0 and 4.0, using artificial lakewater in the respirometer. No significant differences in oxygen uptake were found at these two pH levels. Measurements of oxygen uptake by sea trout fry (Salmo trutta L.) at pH 7.0 are included.
Gonad morphology and sex succession in the protogynous hermaphrodite Hemanthias vivanus (Jordan and Swain)
Authors: Hastings P. A.
Published: January 2006

Hemanthias vivanus, an anthiine serranid common on deep (70–80 m) reefs off eastcentral Florida, is shown to be a protogynous hermaphrodite with observed size ranges as follows: female, 49–77 mm S.L.; transitional 65–74; male, 65–96. Sexes are distinguishable externally as the dorsal spine filaments elongate and colour pattern changes with sex succession. In females, lamellae extend from the lateral and dorsal walls of the bilobed ovary into the lumen. Ova mature within the lamellae and at ovulation pass centrally into the lumen, posteriorly into a common post‐ovarian sinus, and exit through the oviduct. Females possess a discrete tissue band (testicular islets) at the border of the alamellar region, from which testicular tissue proliferates during sex succession and replaces the regressing ovarian tissue. In males, spermatozoa are formed in crypts which drain peripherally into a sperm sinus which forms by rupture of muscular and connective tissue layers surrounding the gonad. The sperm sinus drains posteriorly into the vas deferens which is formed by rupture of collagenous tissue surrounding and posterior to the now vestigial post‐ovarian sinus. The vas deferens and mesonephric duct join within the urogenital papilla. Two smooth muscle bands associated with the infracarinalis medius muscle bands, the collagenous tissue surrounding the gonoduct, and the intestinal lining are implicated in the extrusion of gametes, urine and faeces. At sex succession, ova are resorbed in one of at least three pathways depending upon their stage of development at the onset of sex transformation: unovulated mature ova become encysted with fibroblasts and invaded by cells of an unknown origin; non‐mature yolky ova are invaded and phagocytized by granulosa cells; non‐yolky ova are not invaded but fragment.
The occurrence of Glugea stephani (Hagenmuller, 1899) in American winter flounder, Pseudopleuronects americanus (Walbaum) from the New York‐New Jersey lower bay complex
Authors: Takvorian P. M. , Cali A.
Published: January 2006

American winter flounder, Pseudopleuronectes americanus, Collected in the New York‐New Jersey bay complex, contained cysts in the intestinal tract which were subsequently identified as the microsporidan Glugea stephani. These fish represent 13 collections taken at approximately monthly intervals over a one and a half year period. The winter flounder varied in size from 8 to 33 cm and consequently represented a fish population of diverse age. During this study, a total of 1840 apparently healthy fish were dissected and examined for the presence of Glugea cysts, with an overall parasite infection rate of 6.63%. There was no correlation between size of the fish and percentage of infection. This percentage represents the mean carrying rate of this parasite in the fish population, since these are the fish that have survived the initial infection. This report extends the reported host range to the New York‐New Jersey area. As a further aid in the characterization of G. stephani, we have included ultrastructural details of the spore morphology.
Changes in the nucleotide triphosphate/haemoglobin and nucleotide triphosphate/red cell ratios of rainbow trout, Salmo gairdneri Richardson, subjected to prolonged starvation and bleeding
Authors: Lane H. C. , Rolfe A. E. , Nelson J. R.
Published: January 2006

The nucleotide triphosphate/haemoglobin (NTP/Hb) and nucleotide triphosphate/red cell (NTP/cell) ratios of rainbow trout increased during prolonged starvation. A decline was noted in blood lactic acid concentration. Red cell count, haemoglobin concentration and haematocrit also declined. Changes in mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were found not to be significant. The NTP/Hb and NTP/cell ratios of both fed and starved trout rose seven days following a 15% reduction in blood volume by cardiac puncture. A rise in whole blood NTP concentration was found only in the bleeding response of fed animals. No significant change was noted in blood lactic acid concentration. The decline in haematocrit was significant only in the starved group. In both groups, however, red cell count and blood haemoglobin concentration fell. MCV rose whereas MCHC declined in all bled animals. Changes in MCH were not significant in either group. Negative correlations were noted between red cell count and both the NTP/Hb and NTP/cell ratios and between haemoglobin concentration and the NTP/Hb ratio. Positive correlations were seen between the two ratios and between red cell count and haemoglobin concentration.
Juvenile current response, growth and maturity of above and below waterfall stocks of rainbow trout, Salmo gairdneri
Authors: Northcote T. G.
Published: January 2006

Young rainbow trout were propagated from adults collected from above and below a water‐fall, impassable to upstream fish migration on Kokanee Creek, tributary to Kootenay Lake, British Columbia. The two stocks of young (above and below waterfall) were reared in a hatchery under identical temperature, light and food conditions. Their directional response to water current was tested in a laboratory migration channel during their first summer and autumn. as well as the following spring. During tests in light, both stocks of young trout showed similar current responses, but in darkness the below falls stock showed much more downstream movement in the autumn than than did the above falls stock. In addition, below falls trout had a higher growth rate. were slightly heavier at the same length and matured earlier than the above falls stock. The adaptive significance of these differences are discussed in relation to maintenance of trout populations above waterfalls and to selective pressures faced by migratory below waterfall populations.
Effects of starvation on the melano‐macrophage centres of fish
Authors: Agius C. , Roberts R. J.
Published: January 2006

Starvation resulted in considerably increased deposition of melano‐macrophages within the spleen and kidney of Pleuronectes plalessa, Salmo gairdneri, Xiphophorus helleri, and Tilapia zillii also within the liver and spleen of Scyliorhinus canicula. These results suggest that catabolic tissue breakdown is a major factor contributing to the formation of the pigments within melano‐macrophages.
Reproduction of the summer flounder, Paralichthys dentatus (L.)
Authors: Morse W. W.
Published: January 2006

The reproduction of summer flounder, Paralichthys dentatus (L.), occurring in the Middle Atlantic Bight was studied from 1974–1979. Males dominated the length interval between 21–35 cm t.l. and were essentially absent in samples >55 cm t.l. Females were more abundant in all length intervals >45 cm t.l. Length at maturity ranged from 24–27 cm t.l. for males and from 30–33 cm t.l. for females which coincided with length at age two. Ovarian egg diamerter frequencies indicated summer flounders are serial spawners and the trend in mean and maximum maturity indexes (% ovary weight of total fish weight) indicated spawning began in September and continued through February in 1975 and probably into March in 1976. Annual condition cycle of males peaked in September and was lowest in April while females’ cycle reached a maximum in October which coincided with peak spawning time. Fecundity was related to length, weight and ovary weight for 1974–1977 and the length‐fecundity equation F= 0.0007975 L3.402 was found to be the best predictive relationship. The overall reproductive strategy of summer flounder was discussed and apparently tends to maximize reproductive potential through an extended spawning season, early maturation, high fecundity, serial spawning and extensive spawning migrations.
The feeding periodicity of striped mullet, Mugil cephalus L., in two Florida habitats
Authors: Collins M. R.
Published: January 2006

The feeding periodicity of Mugil cephalus (striped mullet) was investigated during the summer and autumn of 1979 using percentage body weight made up of stomach contents as an indicator of feeding intensity. One study site was freshwater, the other was estuarine and both were tidally influenced. Mullet at both sites feed diurnally, with maximum intensity occurring at about 11.00 hours and little or no feeding occurring at night. Fish from the freshwater site have larger standard length‐specific intestine lengths and also include more plant material in their diet than do mullet from the estuarine site. At both sites fish longer than 28 cm standard length (s.l.) tend to be female; the difference from a 50:50 sex ratio is highly significant in both cases. Females longer than 28 cm s.l. outnumber all other sex and size combinations at the freshwater site, but comprise only 28% of fish collected at the estuarine site.
Age and growth determinations in the catfish, Chrysichthys nigrodigitatus (Lacépède) by use of the dorsal spine
Authors: Ezenwa B. I. O. , Ikusemiju K.
Published: January 2006

Annual rings on the first dorsal spine were used to determine the age and growth of the catfish, Chrysichthys nigrodigitatus (Lacépède), in the Lagos Lagoon, Nigeria. From back‐calculations, it was found that the mean total length ofthe species when the first annulus was formed was 18.5 cm, 32.6 cm for second annulus, 43.5 cm for the third annulus and 53.9 cm for the fourth annulus. It was shown that this species in the Lagos Lagoon attained four years of age and that the fastest growth in length was achieved during the first year of life. Thereafter, increase in length gradually decreased with age. The relationship between the body length and dorsal spine radius was shown to be linear and highly correlated.
Sexual maturation in triploid male plaice (Pleuronectes platessa) and plaice x flounder (Platichthys flesus) hybrids
Authors: Lincoln R. F.
Published: January 2006

Triploid male plaice, Pleuronectes platessa, and plaice x flounder, Platichthys flesus, hybrids produced from cold‐shocked eggs were reared to maturity at three years of age. The testes of triploid hybrids were similar in macroscopic appearance and size to those from control fish but in histological section spermatocyte and spermatid cell formation was grossly abnormal. In two fish the majority of cells appeared to be aborted spermatids and spermatocytes although there were some spermatozoa with enlarged heads and thick bent flagellae.

The testes of mature triploid plaice were similar to controls both in shape and size and in histological section. Spermatocyte and spermatid cell formation was normal, apart from an increase in cell and nuclear size, and fully motile spermatozoa were produced from several fish. Plaice eggs fertilized with semen from triploids showed a slight reduction in fertility compared with controls but developed normally to gastrulation with little mortality. Beyond gastrulation there was increasing mortality associated with abnormalities in the appearance of embryos. Few hatched and none of these survived longer than 48 h. The value of triploidy in fish farming is briefly discussed.
Comparison of early developmental stages and adults of grass carp, Ctenopharyngodon idella, and hybrid carp (female grass carp × male bighead Aristichthys nobilis)
Authors: Kilambi R. V. , Zdinak A.
Published: January 2006

Hybrid carp and grass carp from the zygote to the prolarval stage and adults were compared to establish distinguishing characteristics. Zygote diameter, yolk sac and embryo length were not different between the fishes. Body pigmentation patterns showed distinct separation among the prolarvae of the hybrids and grass carp. Total and preanal myomeres were higher in grass carp larvae than in the hybrids. The grass carp and hybrid larvae also differed in 38% of the proportional morphometric characters.

Average meristic counts of adults were significantly higher in hybrids compared with grass carp. Adults of the two fishes showed significant differences in 63% of the proportional morphometric measurements. Gill raker counts showed no overlap and lateral line scales were smaller and more numerous in the hybrid adults.
Age, growth and rate of food consumption in an upland population of the three‐spined stickleback, Gasterosteus aculeatus L.
Authors: Allen J. R. M. , Wootton R. J.
Published: January 2006

In a population of Gasterosteus aculeatus living in an infertile, upland lake, the fish bred at the age of one year and few survived to breed again. The highest growth rates were achieved in the first month of life, but in comparison with other populations of G. aculeatus growth was slow during the autumn and ceased during the winter. But in spring and early summer, there was a spurt in the growth rate.

Laboratory studies provided regression models for the prediction of the rate of food consumption from measurements of growth. The estimates of the consumption rate indicated the effect of the growth in body size and seasonal variations during the first year of life. It was estimated that a fish of mean length in the population consumed 3150 mg of food in a year in which it grew from 65.8 to 552.0 mg, with an overall gross growth efficiency of 15.4%.

The study illustrated the integration of laboratory and field studies to obtain reasonable estimates of the rate of food consumption by fish throughout their first year of life.
Structure and colour of the integument of the European eel Anguilla anguilla (L.)
Authors: Pankhurst N. W. , Lythgoe J. N.
Published: January 2006

The structure of the integument of 26 wild and nine artificially matured female Anguilla anguilla, and 30 sexually immature eels maintained in controlled lighting, was investigated. Melanophore densities varied in a way unrelated to maturity while xanthophores were progressively lost from lower levels in the skin. Reflecting layers made up of the purines, guanine and hypoxanthine were associated with chromatophore layers. Purine concentrations (as a percentage of total skin dry weight) decreased with maturity but a reorganization of the reflecting elements occurred. Colour changes associated with maturation were due to the redistribution of purines. Spectral and angular reflectance measurements indicate that the integument has camouflage value and colour changes can be related to the change in habitat occurring with migration. The usefulness of colour as an index of sexual maturity is discussed.
Inbreeding depression in the convict cichlid, Cichlasoma nigrofasciatum (Baird and Girard)
Authors: Winemiller K. O. , Taylor D. H.
Published: January 2006

Convict cichlids, Cichlasoma nigrofasciatum, inbred for four and five generations exhibited moderate and severe morphological deformities. Deformed fishes were characterized by a more vertically sloping forehead, irregular jaw, hyoid, opercula and fin structure, reduced growth and irregular swimming behaviour. Inbred fish (F4, F5) did not differ from F1s in their age of maturation or the average size of their first broods. Brood survival was 18.7% in F5 inbred fish, compared to 75.5% in F1s.
The Oriental Goby, Acanthogobius flavimanus (Temminck and Schlegel), an introduced fish in the coastal waters of New South Wales, Australia
Authors: Middleton M. J.
Published: January 2006

Since 1971 over 100 specimens of the oriental goby, Acanthogobius flavimanus, have been collected from New South Wales’ waters. When this species, a native of Japan, was introduced to San Francisco Bay (U.S.A.) it underwent a population explosion, becoming a common member of estuarine fish communities in that area.

The occurrence of both reproductively maturing females and juveniles in the harbours of the Sydney region (central New South Wales coast) suggests that the species may have bred successfully here. However, the relatively low numbers of A. flavimanus collected during the study indicate that as yet there has been no population explosion in New South Wales waters. A number of aspects of the biology and ecology of the species was examined in an attempt to identify features which may limit its distribution and abundance in the Sydney region.

The inhibition of successful reproduction by the relatively warm‐water temperatures in this area and the potential for competition with native fishes are proposed as possible explanations.
Energetic costs at different levels of feeding in juvenile cod, Gadus morhua L.
Authors: Soofiani N. M. , Hawkins A. D.
Published: January 2006

The energetic costs associated with feeding by juvenile cod were determined by means of an open‐circuit respirometer. Fish acclimated to several temperatures (7, 10, 15 and 18°C) were kept at natural lighting levels, and fed inside their individual respirometers. They consumed a diet compounded from natural foods, at five different ration levels, their oxygen consumption being monitored continually over an 11–16 day period.

After each meal the rate of oxygen consumption increased to above the pre‐feeding level, reaching a peak 8–10 h later. With each successive meal the oxygen consumption showed a cumulative increase, reaching a maximum usually after the last meal.

The elevation in metabolic rate associated with feeding was dependent upon ration size, increasing linearly as the food intake increased. The effect was also dependent upon temperature; for fish fed to satiation the total energy cost was equivalent to 11.9, 10.9, 16.4 and 17.1% of the ingested energy at 7, 10, 15 and 18°C respectively. For resting satiated fish the rate of oxygen consumption was close to the maximum rate for active fish.
Distribution and ultrastructure of taste buds in the oropharyngeal cavity of the rainbow trout, Salmo gairdneri Richardson
Authors: Ezeasor D. N.
Published: January 2006

The distribution, external surface morphology and ultrastructure of taste buds in the oropharyngeal cavity of the rainbow trout, Salmo gairdneri Richardson, were studied using scanning and transmission electron microscopes (SEM and TEM). The SEM revealed three taste bud types, varying only in their degree of elevation from the general level of the epithelium. Types I and II were located on elevated papillae associated with teeth on the dentary, maxilla, palate, tongue and pharyngeal pads while the unelevated Type III were mainly found in the anterior (branchial) pharynx.

Each taste bud was composed of four cell types: basal, dark, intermediate and light cells, the apical processes of the last three filling the taste pores. The intermediate and light cells appeared similar in ultrastructure, varying only in the amount and organization of smooth endoplasmic reticulum (SER) in their cytoplasm. In addition to its contacts with the processes of intragemmal nerves distally, the basal cells established independent contacts with processes of extragemmal nerves basally. It is suggested that the distribution of the taste buds and their close association with teeth are adaptations to the predatory feeding habit of the rainbow trout. Age differences may account for the existence of two types of gustatory cells and the manner of innervation of the taste bud suggests the existence of two pathways for the transmission of gustatory sensation to the central nervous system (CNS).
Some observations on the effects of feeding frequency on the food intake and growth of plaice, Pleuronectes platessa L.
Authors: Jobling M.
Published: January 2006

The segregation of plaice, Pleuronectes platessa, into groups of uniform size can be used to reduce the formation of size hierarchies, even under conditions of limited food supply. When access to food was limited the fish responded by becoming hyperphagic. This resulted in an increase in growth rate following an initial growth check. However, even after hyperphagic adaptation, intermittently fed fish grew at slower rates than those allowed more frequent access to food. Hyperphagia was accompanied by an increase in relative stomach weight and gastric capacity but did not affect fat storage and proximate chemical composition.
Observations on growth rates of Arctic charr, Salvelinus alpinus (L.), reared at low temperature
Authors: Wandsvik A. , Jobling M.
Published: January 2006

Food intake and growth of Arctic charr, Salvelinus alpinus, in fresh water was studied at three temperatures 2·9, 8·4 and 13·1° C). Best growth and highest food intake occurred at 13·1°C. The approximate chemical composition was dependent upon rearing temperature, fish reared at the highest temperature depositing large quantities of fat. Fish were later grown on in either fresh or salt water where two growth patterns were observed. In the light of published data for Salvelinus spp., it is suggested that the poorest growth was shown by fish which were incapable of complete adaptation to saltwater conditions.
Overwintering mortality of migratory Arctic charr, Salvelinus alpinus, (L.) reared in salt water
Authors: Wandsvik A. , Jobling M.
Published: January 2006

The mortality of Arctic charr, Salvelinus alpinus, previously grown‐on in salt water during the summer months, was studied during the winter 1980–81. Mortality did not appear to be related to a‘ critical size‘ but rather to rates of growth shown by the fish during the summer months. Mortality was high amongst the slow‐growing fish.

The results are discussed in relation to published data on the osmoregulatory capabilities of Salvelinus spp.
Reproductive biology of the tropical fish Trichogaster pectoralis (Regan)
Authors: Hails A. J. , Abdullah Z.
Published: January 2006

The breeding cycle of an air‐breathing Anabantid, Trichogaster pectoralis was studied in Malaysia. The species was found to breed all the year but with pronounced peaks of activity associated with the two wetter periods in the year. The advantages of this timing and the cues which stimulate gonadal activity are discussed. From the study of oocyte distribution in selected ovaries it was concluded that T. pectoralis is a total spawner although a batch of ripe oocytes may be released over an extended period of time. Fecundity was found to be related to length of fish by the formula (log10 Egg no.)=–4.6854+4.3080 log10 standard length (S.L.) (mm).