bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of stocking density and food density on survival, growth and yield of laboratory‐reared larvae of sea bream Archosargus rhomboidalis (L.) (Sparidae)*
Authors: Houde Edward D.
Published: January 2006

Growth and survival of sea bream, Archosargus rhomboidalis (L.) larvae were affected by both abundance of eggs that were initially stocked in 75 1 rearing systems and by the concentration of copepod nauplii and copepodites that were fed to larvae. Stocking levels were 2, 4, 8,16 or 32 per litre while food abundance was maintained at approximately 100, 500, 1500 or 3000 per litre. Experiments were of 16 days duration at 26° C. Survival was best, often exceeding 60%, when food levels were 1500 or 3000 per litre and when stocking density did not exceed 8 eggs per litre. Growth was best at the lowest stocking densities and highest food levels. The highest total yields in wet weight occurred at 8 per litre stock density and 3000 per litre food level. Mean wet weight per survivor and yield per stocked egg were greatest at the lowest stocking densities and highest food levels. A 500 per litre food level was marginal for growth and survival, and 100 per litre produced significant survival only at the 2 per litre stocking density. Two experiments at 6000 and 10 000 per litre food levels at 4 per litre stock density gave the best observed growth, and survival as good as in any other experiments. Possible relations between sea bream larvae and their food supply in the natural environment are discussed. Results also are discussed in terms of their possible contribution to aquaculture efforts.
A comparison of the effects of temperature on wound healing in a tropical and a temperate teleost
Authors: Anderson C. D. , Roberts R. J.
Published: January 2006

The rate of healing of a surgical wound was studied in two teleost fish, one with a tropical, and the other with a temperate temperature range. Comparisons were made of both the rate and qualitative nature of wound healing within and between species at temperatures of 30,23,10 and 5° C. The rate of wound healing was found to be proportional to temperature and temperature stress had little effect on healing rates. The findings were related to reported rates of wound healing in man. In general the wounds studied healed at a rate comparable to those reported for the healing of superficial skin wounds in man and other mammals despite the fact that the fish wounds were not merely superficial but involved integument and muscle.
Growth increments and some flesh and gonad characteristics of juvenile coho salmon receiving diets supplemented with 17α‐methyltestosterone
Authors: Fagerlund U. H. M. , McBride J. R.
Published: January 2006

Juvenile coho salmon Oncorhynchus kisutch (Walbaum) received a diet of Oregon Moist Pellets supplemented with either 10, 1, 0.2 or 0 ppm of 17α‐methyltestosterone for 72 weeks. The fish were held in fresh water during the first 57 weeks and in salt water during the remaining time of the study. At the end of the fresh water residency, the fish receiving 10 and 1 ppm of steroid showed a net increase in weight of 125 and 71 % respectively over the controls. Both test groups also gained in length, but the 10 ppm group gained proportionately less, which resulted in a thicker body. After transfer to salt water at the normal time of smolting, there was a decrease in the rate of growth in weight and length of the two groups receiving the high doses of steroid. The decrease was most noticeable in the 10 ppm group and a number of mortalities occurred in this group.

Testes of fish receiving 10 ppm of the steroid became hypertrophied and later degenerated with loss of spertnatogonia; the ovaries were not affected. 17α‐methyltestosterone fed at 10 ppm for 49 weeks increased the lipid content of the flesh from 2.4 to 3.5 % and decreased the amount of flesh from 35.0 to 28.5 % of body weight. No change in the moisture content was found. External changes noted in the 10 ppm group included loss of silvering, deepening of the body, particularly in the region of the anal fin, and widening of the lower jaw.
Induced polyploidy in Tilapia aurea (Steindachner) by means of temperature shock treatment
Authors: Valenti R. J.
Published: January 2006

A technique for increasing ploidy in the blue tilapia, Tilapia aurea, was investigated for the purpose of determining its effect on standard length. Gametes of T. aurea were stripped from ripe adults and eggs were fertilized with donor sperm from several males. A description of the extra‐oral incubation system used for the embryos is provided. This system resulted in a maximum of 90% successful hatch. Normal egg development was interrupted by immersion of newly fertilized eggs (15 min post‐insemination) in cold or hot water for various durations. The reliability of these techniques for inducing polyploidy was examined using increased volume of erythrocyte nuclei as a criteria for success. A cold shock of from 32°C (ambient) to 11°C for a 1 h duration resulted in the largest incidence of polyploidy (75 %). Polyploid fish were found to be larger than diploid siblings when measured at 14 weeks of age.
A diurnal rhythm of pituitary prolactin activity with diurnal effects of mammalian and teleostean prolactin on total body lipid deposition and liver lipid metabolism in teleost fishes*
Authors: De Vlaming Victor L. , Sage Martin , Tiegs Robert
Published: January 2006

Previous investigations have shown that mammalian prolactin has a pronounced effect on lipid deposition in teleost fishes (e.g. Meier et al., 1971; de Vlaming & Sage, 1972). Prolactin can be either lipogenic or lipolytic depending on when during the day it is injected. Studies were initiated to determine whether the diurnal effects of prolactin on lipid metabolism in Fundulus similis vary with season or photoperiod acclimation. Data presented here indicate that the diurnal rhythm of response to prolactin persists in the pre‐spawning and post‐spawning seasons if F. similis is maintained on a long photoperiod. When animals are acclimated to a short photoperiod, treatment with mammalian prolactin either early or late in the photoperiod causes lipid depletion. Homogenates of the portion of the pituitary containing only prolactin cells cause lipid depletion in F. similis when injected early during a long photoperiod, but stimulate lipogenesis if injected late in the photoperiod; these results imply that fish prolactin may be involved in lipid metabolism. Furthermore, prolactin activity in the pituitary of F. similis varies diurnally. In vitro studies of lipid metabolism in Notemigonous crysoleucas and Ictalurus natalis suggest that the liver may be one of the target organs for prolactin.
The development of carp gonads in warm water aquaria
Authors: Gupta S.
Published: January 2006

The development of carp gonads in warm water (23°C) aquaria under controlled conditions is described. In this environment males mature at 6 months of age. Females ripen at 14 months, and by 15 months 25% of these have started to spawn, whereas under natural conditions female European carp do not ripen until they are 4 years old. Fishes do not lay all their eggs at once, as evinced by the finding of partly‐spent ovaries. Sexual maturation of the ovaries has been described in six stages, based on histological changes, and associated with changes in the female gonado‐somatic index and the maximum ova diameter. The maturation of testes occurs in four stages. The percentage incidence of each stage of ovarian maturation has been calculated for the 6th to the 15th month. Larger fishes become sexually mature before smaller fishes.
The effects of starvation and force‐feeding on the metabolism of the Northern pike, Esox lucius L.
Authors: Ince Bernard W. , Thorpe Alan
Published: January 2006

The effects of starvation and force‐feeding on certain tissue and blood constituents were studied in the Northern pike, Esox lucius L. Starvation resulted in a reduction of liver and muscle glycogen and liver lipid. Blood glucose concentration and haematocrit were reduced, total plasma cholesterol levels were increased, while the levels of plasma free fatty acids (FFA), amio acid nitrogen and protein remained unaltered. No significant changes were observed in either muscle protein, muscle water or the response to amino acid loading during the starvation period.

The force‐feeding of pike starved for 3 months resulted in liver lipid and muscle glycogen being increased to levels higher than those observed in freshly‐captured fish. Liver glycogen, however, increased to values only slightly higher than those of starved animals. Furthermore, while force‐feeding had little effect on plasma FFA or protein concentrations, blood glucose, plasma cholesterol and haematocrit returned to the levels found in freshlycaptured fish and those of amino acid nitrogen were higher.

The results indicate that pike are well adapted for periods of prolonged starvation and that hepatic and extra‐hepatic lipid and glycogen stores serve for metabolic needs during food shortage, while body protein is conserved. The endocrine basis for these changes in the tissue and blood constituents is discussed.
Hydrogen ion concentration in the gastrointestinal tract of channel catfish
Authors: Page Jimmy W. , Andrews James W. , Murai Takeshi , Murray Morgan W.
Published: January 2006

Hydrogen ion concentrations (pH) of the digestive tracts of channel catfish were determined for fish of two sizes (892 and 134 g average weight) at two environmental temperatures (28 and 23°C). Acidic conditions (pH 2–4) were present in the stomach contents of all catfish with slightly higher pH values in stomachs of fish at 28°C. The pH increased to slightly alkaline values (pH 7–9) in the duodenum and reached a maximum level (pH 8.6) in the upper intestinal region and then decreased in the lower segments to approach neutrality in the colon. The pH of the bile ranged from 6.1 to 7.5 and was higher in fish maintained at 28°C. Higher environmental temperatures (28°C) resulted in a slightly lower pH throughout the intestinal and colon segments. The larger catfish had lower intestinal length/body weight ratios than smaller catfish. As the result of distension due to increased food consumption, catfish maintained at 28°C had shorter intestinal tracts than catfish maintained at 23°C.
Effects of feeding on the swimming activity and growth of Ophiocephalus striatus
Authors: Vivekanandan E.
Published: January 2006

Swimming activity of the obligatory air‐breathing fish Ophiocephalus striatus reared in cylindrical aquaria on different rations (0–43.3 mg/g/day) increased from 58 m/day for the starving group to 439 m/day for the group fed a maximum ration. Swimming speed also increased from 2.4 cm/sec in the former group to 5.2 cm/sec in the latter group. Owing to sustained swimming activity and the consequent fatigue, the test individuals ‘hung’ to the surface for a definite interval. Duration of surface ‘hanging’ increased from 3.2 h/day to 15.8 h/day with decreasing ration. The group receiving 25.5 mg/g/day converted most efficiently (28%). The maintenance energy cost is equivalent to 10 mg/g/day and dry substance equivalent to 5 or 12 mg/g/day was expended on the sustained swimming activity by the fish receiving the optimum (25 mg/g/day) or the maximum (43 mg/g/day) ration.
Productivity of a herbivorous pupfish population (Cyprinodon nevadensis) in a warm desert stream
Authors: Naiman Robert J.
Published: January 2006

Production and food intake by an herbivorous pupfish population (Cyprinodon nevadensis amargosae) living in the outflow of a thermal artesian well (Tecopa Bore) near Death Valley, California is described. Water issues from the ground at 47.5° C and cools 8.12° C before leaving the study area 300 m from the source. High stream temperatures restricted the pupfish population to some 41 % of the study area, with a resulting mean density of 89 individuals m−2 (range = 13 to 196m−2). Biomass estimates ranged from 7 kcal m−2 to 42 kcal m−2. The mean annual standing crop of pupfishes (24 kcal m−2) turned over about five times annually. Growth rates were highest in juveniles (♂= 9.5% day−1) and slowest in large adults (♀= 08% day−1). Monthly production ranged from 22 kcal m−2 in September to 3 kcal m−2 in July and August. Pupfish in Tecopa Bore fed on algae and detritus, ingesting 1941 kcal m−2 yr−1 or 17.5% of the annual net primary production. 119 kcal m−2 yr−1 was deposited in growth. This latter value is approximately ten times greater than values previously reported for large carnivorous fishes but is comparable lo values reported for herbivorous fishes under pond culture.
Functional morphology of the bulbus arteriosus of rainbow trout (Salmo gairdneri Richardson)
Authors: Priede Imants G.
Published: January 2006

The rate of expansion in volume of the bulbus arteriosus with increase in pressure is measured. From this it is calculated the elastic rebound of the bulbus can account for approximately 25 % of blood flow in the ventral aorta; this proportion decreases as cardiac output increases. The structure of the wall of the bulbus is shown to consist of a compact outer layer with a series of separate longitudinal elements on the inner surface. These elements are connected to the compact layer by numerous radial fibres. This structure equalizes strain in all the structural elements of the wall during large changes in volume. Evidence is discussed which shows that the bulbus arteriosus in teleosts is morphologically and biochemically distinct from the ventral aorta. The bulbus is probably of cardiac origin rather than an expansion of the posterior end of the aorta as generally supposed.
Morphology and function of the lateral line of juvenile steelhead trout in relation to gas‐bubble disease*
Authors: Weber Douglas D. , Schiewe Michael H.
Published: January 2006

General morphology of the lateral line of juvenile steelhead trout, Salmo gairdneri, is described. Through electrophysiological monitoring of individual nerve fibres, control patterns for spontaneous activity and reaction to sensory receptor stimulation were established. Spontaneous activity has a positive correlation with temperature and number of receptors innervated. Presence of directional sensitivity and response to near field water displacement at different frequencies is similar to that found in other fishes and amphibians. Normal lateral line response to a standardized set of stimuli was compared with the response of fish affected by gas‐bubble disease. Results show that as gas emboli formed in the scale pockets of the trunk lateral line of stressed fish, the ability to respond to stimuli was either diminished or completely disappeared. Further testing demonstrated that this sensory loss was reversible and that upon return to equilibrated water gas emboli disappeared and normal function was regained. This sublethal effect of gas‐bubble disease on the lateral line sensory system may be an important element contributing to indirect mortality.
The biology of Lates species (Nile perch) in Lake Tanganyika, and the status of the pelagic fishery for Lates species and Luciolates stappersii (Blgr.)
Authors: Coulter G. W.
Published: January 2006

Three Lates species, L. mariae (Stdr.), L. microlepis (Blgr.), L. angustifrons (Blgr.) and Luciolates stappersii (Blgr.) which belongs to a monotypic genus occur only in Lake Tanganyika. They are the principal predators in the pelagic and benthic fish communities. Data are presented on distribution, growth, length‐weight relationships, condition, reproduction and food in the Lates spp. After a post‐larval pelagic phase, each Lates sp, spends 1 year in littoral weed. Thereafter, L. mariae adopts a benthic habitat moving into deep water, L. microlepis becomes exclusively pelagic and L. angustifrons occurs from the littoral to near the limit of the oxygenated zone. Cycles in breeding correspond with seasonal maxima in clupeid prey, and changes in growth rate within a year are probably related to physiological cycles rather than to variations in the physical environment. Salient morphological and ecological adaptations are discussed.

Local abundance and vagility of Lates stocks seem related to basin morphometry and depth of the oxygenated layer. L. microlepis has most vagility. The Lates appear highly susceptible to intensive fishing by purse‐seines, and have been fished‐up in the southeast arm in Zambia and in the Burundi sector, where only small populations remain. With reduced predation, the clupeid biomass has increased. The change to dominance of small species may be accomplished rapidly in L. Tanganyika under such conditions of exploitation. However, the type of species successions well‐known in large temperate lakes are unlikely to occur because of the high degree of specialization in these fishes. A simplified pelagic community is foreseen, consisting almost entirely of clupeids and Luciolates, in which the total fish biomass will be determined above some intensive level of fishing and from year to year by the environmental factors controlling survival of young and plank‐tonic food supply. Quantitative equilibrium between the few species will be determined mainly by gear selectivity and total fishing stress, and the community may be sufficiently robust by reason of its rapid turn‐over rates to permit a largely empirical approach to management.
The biology of Myxosoma cerebralis: the causative organism of whirling disease of salmonids
Authors: Halliday M. M.
Published: January 2006

The literature describing the biology and control of Myxosoma cerebralis (whirling disease) is reviewed. New data on the world distribution of the parasite are presented. It is concluded that the presence of M. cerebralis is not an important limiting factor in salmonid fanning per se but only limits methods of production.
Toxic action of several lethal concentrations of an anionic detergent on the gills of the brown trout (Salmo trutta L.)
Authors: Abel P. D.
Published: January 2006

The pathological effects often lethal concentrations of the anionic detergent, sodium lauryl sulphate, on the gills of Salmo trutta L. have been studied by light and electron microscopy. At concentrations to 120 mg/1 (medium survival times >1 h), epithelial cell death is associated with lysosome formation. Acute inflammation of the gill tissue, extensive detachment of the epithelium and, except at the lowest concentrations, collapse of the pillar cell system occur. At concentrations above 120 mg/1 (medium survival times <1 h) very rapid lysis of cells results in the complete disruption of cellular and tissue structure. Changes in the gross structure of the gills are explainable in terms of the rate and nature of toxic action at the cellular level. Review of the biomedical literature suggests the observed effects of sodium lauryl sulphate on gill cells correspond to the two mechanisms by which detergents cause death in isolated cells. These are autolysis, i.e. lysis by the action of the cell's own enzymes, induced by an initial lesion in the cell membrane whose precise nature is not known; and rapid lysis by the direct action of the detergent on the cell constituents.
Occult haemoglobin in fish skin mucus as an indicator of early stress
Authors: Smith Albert C. , Ramos Franklin
Published: January 2006

Early induced stress may result in the release of free haemoglobin into the skin mucus of teleostean fishes. If this were the case, it could be indicated quickly and simply by the colour change of a commercially available haemoglobin test strip. Preliminary tests on Mugil cephalus (grey mullet) encouraged more extensive investigations with Chanos chanos (milkfish), Caranx ignobilis (papio), Albula vulpes (bonefish), and Chaetodon miliaris (butterfly fish). The results indicated that unstressed individuals of these species have no detectable haemoglobin in their skin mucus but, within 2–4 min, the pigment will appear in occult amounts if stress is applied. Additional studies confirmed that it was haemoglobin and no other possible contaminants in the mucus which caused the colour change of the test strip.

The technique is simple and quick, and is itself harmless to the fish. It is of immediate potential value to fish culturists for the detection of early stress conditions. Efforts can then be made to lessen or remove the stress conditions before debility and possibly overt disease take over. A further application of the technique may be the identification of individuals genetically better able to resist disease.
Studies on Ligula intestinalis Some aspects of the pathology in the second intermediate host
Authors: Sweeting R. A.
Published: January 2006

A 3 year survey of a lake, in which 120 roach, Rutilus rutilus, were examined revealed the presence of the plerocercoids of Ligula intestinalis in more than 90 % of the fish. The average number of parasites per fish was 4.2 although fish exceeding 32 g were not ligulosed. Gudgeon, Gobio gobio, of all sizes were affected. Implants of the plerocercoids into small roach, gudgeon and goldfish, Carassius auratus, were successful but not in the case of Perca fluviatilis, Esox lucius and Leuciscus cephalus. The pathological effects of the plerocercoids on roach and gudgeon are described.
The effect of parasitism on the toxicity of cadmium to the three‐spined stickleback, Gasterosteus aculeatus L.
Authors: Pascoe D. , Cram P.
Published: January 2006

The toxicity of cadmium to sticklebacks was determined over a wide range of concentrations. The 96 h LC50 was found to be 6.5 mg Cd I−1. The shape of the time‐concentration curve suggests that cadmium may have two toxic mechanisms. The median period of survival for fish infected with the plerocercoids of the cestode, Schistocephalus solidus, was found to be considerably shorter than for non‐parasitized fish. This observation is considered in the light of the known effects of 5. solidus on its host.
A study of Vibrio anguillarum from farmed and wild fish using principal components analysis
Authors: Håstein T. , Smith J. E.
Published: January 2006

Principal components analysis revealed two main groups among 163 Vibrio anguillarum cultures from diseased fish from Norwegian waters. Nearly all isolates from farmed salmonids fell in group I (arabinose positive) but those from wild fish, particularly saithe Gadus virens, more commonly appeared in group II (arabinose negative).
Growth and diet dependant structural adaptations of the digestive tract in juvenile grass carp (Ctenopharyngodon idella, Val.)
Authors: Stroband H. W. J.
Published: January 2006

The morphology of the intestinal epithelium is described and compared with published data. In the gut of this stomachless fish, three zones can be distinguished based on light and electron microscopic observations of absorptive cells: a rostral zone with numerous fat droplets, a second zone with large P.A.S.‐positive supranuclear vacuoles and pinocytotic vesicles, and a third zone without these characteristics. In these zones deep invaginations of the cell membrane is a feature of the basal part of the cells. The presence of pinocytotic vesicles in the second zone is considered evidence of the uptake of undigested protein‐like substances.

Juvenile grass carp from 15 to 335 days, fed on either animal or vegetable food, were measured. The growth rates indicate that animal food stimulates rapid growth. The data also show a vegetable diet causes a slight increase in relative gut length, mainly in the length of the first zone.
Food and feeding of the mormyrid fishes of Lake Kainji, Nigeria, with special reference to seasonal variation and interspecific differences
Authors: Blake B. F.
Published: January 2006

The feeding habits of mormyrids from Lake Kainji, Nigeria, are discussed in relation to the decreased abundance of these fish since impoundment in 1968. Evidence is presented of both intra‐specific seasonal variation in diet and inter‐specific trophic divergence. These variable factors are discussed in relation to the degree of success achieved by certain species in the lake.
Relationship between elver recruitment and changes in the sex ratio of silver eels Anguilla anguilla L. migrating from Lough Neagh, Northern Ireland
Authors: Parsons J. , Vickers K. U. , Warden Y.
Published: January 2006

Between 1932–1947 and from 1960 onwards, elvers have been trapped near the mouth of the River Bann, Northern Ireland, and released into Lough Neagh. Each period of elver transport has been followed by a marked increase in the proportion of male silver eels migrating from the lough. Catches of silver eels were sampled on several nights each year from 1965–1974, and the lengths of a total of 20358 eels measured showed a progressive increase in the percentage of male eels from 9.3‐86.0 % during this period. Various reasons for this change were examined. The different ages at which male and female eels migrate to the sea was not important. There was no evidence to support the hypothesis that male elvers normally remain in estuarine conditions, and their transport to the lough was therefore unnatural. An increasing fishing effort for yellow eels, such as occurred following the introduction of trawling in 1960, would favour males since small eels were returned to the lough. It was not thought, however, that this was a major cause of the change in sex ratio. Instead, elver transport appeared to be directly implicated, possibly by the overstocking of Lough Neagh, and the phenotypic determination of progressively more male eels, but the evidence for this suggestion was inconclusive.
The effect of temperature and mass on routine metabolism in Sarotherodon (Tilapia)mossambicus (Peters)
Authors: Caulton M. S.
Published: January 2006

A reappraisal of oxygen uptake by Sarotherodon mossambicus was undertaken using a continuous flow respirometer. Measurements were obtained over the temperature range 16°C–37°C for fish weighing between 10 g and 150 g. Oxygen uptake was converted to energy equivalents (Qox) using the value 13.68 J mg O2–1and the routine metabolic energy expenditure can be described by the equation E=0.0086 t2 0783M0 652 where E is the energy requirement for routine metabolism expressed in J h‐1, t the temperature in °C and M the mass in g.
Hybrids of bleak, Alburnus alburnus, and chub, Leuciscus cephalus in English rivers
Authors: Wheeler Alwyne
Published: January 2006

The occurrence of hybrids between bleak, Alburnus alburnus, and chub, Leuciscus cephalus is reported from four discrete river systems in England. The hybrids are described and illustrated, and means of identification from the parent species are given. Bleak × chub hybrids appear to be moderately common and on superficial examination resemble the bleak parent species more than the chub.
Acute toxicity of copper, zinc and manganese in single and mixed salt solutions to juvenile longfin dace, Agosia chrysogaster
Authors: Lewis M.
Published: January 2006

The acute toxicity of copper, zinc and manganese and copper‐zinc and copper‐manganese mixtures were determined for juvenile longfin dace, Agosia chrysogaster in hard water bioassays (mean=218 mg 1−1 CaCO3). Copper‐zinc was the most lethal toxicant (96‐h L.c.50= 0.21 mg 1−1 copper and 0.28 mg 1−1 zinc) and exhibited a more than additive toxicity which was in contrast to the additive toxicity of copper‐manganese mixtures (96‐h L.c.50= 0.45 mg 1−1 copper and 64.0 mg 1−1 manganese). The toxicity of copper (96‐h L.c.50= 0.86 mg 1−1) and zinc (96‐h L.c.50= 0.79 mg 1−1) to the fish was similar but both were considerably more lethal than manganese (96‐h L.c.50= 130 mg 1−1).
Toxic effects of zinc on fathead minnows Pimephales promelas in soft water
Authors: Benoit D. A. , Holcombe G. W.
Published: January 2006

A fathead minnow life‐cycle exposure to various zinc concentrations demonstrated that the most sensitive indicators of zinc toxicity were egg adhesiveness and fragility, which were significantly affected at 145 μg Zn 1−1 and above, but were not affected at 78 μg Zn 1−1 and below. These effects occurred shortly after the eggs were spawned (during water hardening) and therefore were not related to effects on the parental fish. Hatchability and survival of larvae were significantly reduced, and deformities at hatching were significantly increased at 295 ug Zn 1−1 and above. Acclimated and unacclimated groups of larvae exposed to identical zinc concentrations for 8 weeks after hatch showed only slight differences in sensitivity.
Locomotor activity of the bluegill Lepomis macrochirus: hyperactivity induced by sublethal concentrations of cadmium, chromium and zinc
Authors: Ellgaard Erik G. , Tusa Joseph E. , Malizia Anthony A.
Published: January 2006

A quantitative description of the effects of sublethal concentrations of cadmium, chromium and zinc on the swimming activities of the bluegill is presented. Locomotor activities of fish in 0.1 and 0.25 mg 1−1 cadmium are respectively 1.5 and 7.8 times the activities of control fish. Fish in 0.5 mg 1−1 cadmium, a concentration killing 30% in two weeks, were less active than controls. Fish in 0.05, 2.4 and 24.0 mg 1−1 chromium were respectively 1.2, 3.6 and 6.5 times as active as controls. Fish in 0.1 and 5.0 mg 1−1 zinc were respectively 1.3 and 3.8 times as active as controls. Thus metals effect hyperactive locomotor responses by the bluegill in a concentration‐dependent relationship.
Aspects of the biology and ecology of Caribbean reef fishes: Serranidae (hinds and groupers)
Authors: Thompson R. , Munro J. L.
Published: January 2006

Hinds and groupers (Teleostei, Serranidae) form a valuable component of catches of reef fishes in the Caribbean Sea and adjacent regions. Investigations of species in Jamaican waters have covered relative and absolute growth rates, spawning seasons, fecundity, size at maturity and at sex change, and size compositions, mortality rates, and relative abundances of exploited and unexploited populations.
Systematics of the Irish pollan (Coregonus pollan Thompson): an electrophoretic comparison with other Holarctic Coregoninae
Authors: Ferguson A. , Himberg K‐J. M. , Svärdson G.
Published: January 2006

Evidence is presented on the genetic relationships of 35 coregonine populations from Alaska, Britain, Ireland, Finland and Sweden. This evidence is derived from an electrophoretic analysis of 27 enzyme loci and additional ‘general protein loci’. The Irish pollan C. pollan and the Alaskan C. autumnalis gave identical electrophoretic patterns for all proteins suggesting that they are conspecific and separated only since the last glaciation. C. peled, C. albula and the ‘C. lavaretus’ complex gave unique patterns for a number of proteins. The Fn C. oxyrhynchus X C albula hybrids, from a lake where no other coregonines occur gave a unique pattern for the enzyme phosphoglucose isomerase but all other enzymes were electrophoretically identical to the C. oxyrhynchus parent and the mean gill raker number was closer to this species than in the F1 hybrid.
Studies on the chemical nature of feeding stimulants for rainbow trout, Salmo gairdneri Richardson
Authors: Adron J. W. , Mackie A. M.
Published: January 2006

Rainbow trout trained to operate a demand feeder showed a marked preference for a diet flavoured with a synthetic mixture of chemicals over the unfavoured diet. The gustatory feeding stimulant activity resided in the amino acid fraction and was stereospeciflc for the L‐forms. Certain mixtures of L‐amino acids were stimulatory, while the individual components of the mixtures were inactive or repellent.
Annual cycle in female Three‐spined sticklebacks (Gasterosteus aculeatus L.) from an upland and lowland population
Authors: Wootton R. J. , Evans G. W. , Mills L.
Published: January 2006

The annual cycles in female Three‐spined sticklebacks from an upland (275 m) and a lowland (25 m) population were compared. The average length and weight of the lowland females were greater, but in both populations growth was checked in winter and again in the breeding season. Both populations also showed a winter decline in condition followed by a sharp increase in spring associated with the maturation of the ovaries. The hepato‐somatic index of the females also increased during the spring, but the dry matter content of the liver declined during the spring and early summer. Lowland females had larger livers than the upland fish. In both populations average gonadosomatic index increased steadily throughout the winter, then abruptly in spring. The lowland population bred from May to early August, but the upland population bred only in May.

The energy content of the carcases of females was lowest in winter and again during the breeding season whereas the ash content showed maxima at these two periods. Lipid and glycogen analyses of the carcase, liver and ovaries also suggested that winter and the breeding season were periods of depletion from the carcase and liver, but not from the ovaries.

The observations indicate that the ovaries are to some extent insulated from fluctuations in resource availability. This supports experimental studies which indicate that egg production in the female stickleback can be subsidised by depletion from the carcase and liver when necessary.
Growth of grass carp fed natural and prepared diets under intensive culture
Authors: Shireman Jerome V. , Colle Douglas E. , Rottmann Roger W.
Published: January 2006

Grass carp were arranged in two groups with an average individual weight of 63 g and 3 g respectively. They were maintained in circular tanks and each group size was fed one of four experimental diets consisting of Purina catfish chow pellets, 50 % catfish chow ryegrass pellets, 100% ryegrass pellets and fresh duckweed, Lemna minima. In this study a high biomass, excellent growth and satisfactory survival rates were obtained when the fish were fed duckweed; the other diets were less satisfactory. The 100% ryegrass pellets gave the least weight gains and on this diet the smaller fish showed lower survival rates and more abnormalities. The feeding experiment lasted 68 days.
Nesting Behaviour of Harpagifer bispinis in Arthur Harbour, Antarctic Peninsula
Authors: Daniels Robert A.
Published: January 2006

Observations of the nesting behaviour of the plunder fish, Harpagifer bispinis, from laboratory tanks at Palmer Station and from diving in Arthur Harbour, Anvers Island, Antarctic Peninsula, are the first to be recorded for any antarctic fish. Females of this species construct a nest and, unless removed, guard it throughout the four month incubation period. Guards clean the eggs and protect them from predators and parasites. If a guarding female is removed from a nest, another fish assumes guard responsibilities. This species exhibits traits which are common in other antarctic forms. The sequence of reproductive events affords adults, eggs and fry a high degree of protection and allows each stage to use available resources fully.
Feeding ecology of four fishes from a mangrove creek in north Queensland, Australia
Authors: Beumer J. P.
Published: January 2006

The feeding ecology of four species of fish is described in terms of associations of body form, feeding structures, and stomach contents; and of seasonal variations in diet. Black bream, Acanthopagrus berda (Forskal, 1775), and the hair‐finned goby, Ctenogobius criniger (Valenciennes, 1837), are predominantly carnivorous; milk‐spotted toadfish, Chelonodon patoca (Hamilton‐Buchanan, 1822), largely omnivorous; and bony bream, Anodontostoma chacunda (Hamilton‐Buchanan, 1822), detritivorous. The results illustrate the role of a mangrove creek in the ecology of the four species of fish and show the mangrove creek provides a nursery for A. berda and C. patoca.
Identification of juvenile natural hybrids between Atlantic salmon (Salmo solar L.) and trout(Salmo trutta L.)
Authors: Solomon D. J. , Child A. R.
Published: January 2006

The identification of two wild salmonid smolts, suspected to be hybrids between Atlantic salmon (Salmo salar) and trout (S trutta) on morphological grounds, was confirmed by electrophoretic separation of serum proteins. A third, trout‐like, hybrid was identified in a sample of parr. Hybrids showed presence of both parent types of esterase, prealbumin and transferrin.
Seasonal and diurnal rhythms of thyroidal status in the rainbow trout, Salmo gairdneri Richardson
Authors: Osborn R. H. , Simpson T. H. , Youngson A. F.
Published: January 2006

The concentrations of thyroxine (T4) and triiodothyronine (T3) in the blood plasma of rainbow trout (Salmo gairdneri Richardson) at intervals throughout the year have been measured by a chemically specific gas‐liquid chromatographic (GLC) method. Mean hormone levels showed a seasonal variation, maximal levels of both hormones occurring in winter and minimal concentrations in mid summer. An apparent secondary maximum in mean T4 and T3 concentrations was observed in spring. (T4)/(T3) ratios have been found to be highest in winter and lowest in summer. A radioimmunoassay procedure, validated by GLC analyses, revealed the presence of a diurnal rhythm in serum T4 levels of trout sampled in September and in April.
The effect of acid water on the hatching of salmonid eggs
Authors: Carrick T. R.
Published: January 2006

The survival of salmon Salmo salar, sea trout and brown trout Salmo trutta eggs in acid water in the range pH 3·5±7·0 was investigated over a period of three winters. The effects of fertilising the eggs in acid water at pH 4·0, 4·5 and 5·0, and dilution of the test media were also studied. There was considerable yearly variation in the numbers of eggs which hatched, but there were no marked differences between the three species in the tolerances of the eggs to acid water; pH 3·5 was lethal within 10 days to all the eggs, but at pH 4·5 and higher pH levels there was no obvious difference in hatching attributable to acidity.
Annual changes in the ovarian activity of the freshwater teleost, Barbus luteus (Heckel) from Southern Iraq
Authors: Al‐Daham Najim K. , Bhatti M. Nazir
Published: January 2006

The present paper describes the morphology, histology, and annual cyclical changes in the ovaries of Barbus luteus (Heckel). The ovaries are paired structures, joined by short oviducts. The ovarian structure consists of a number of lamellae, which contain the germ cells in various phases of maturation—immature, maturing and mature. Two types of yolk have been reported in the oocyte. The endocrine function of the gonads has been attributed to the follicular cells forming the ‘pre‐ovulatory corpus luteum’ and ‘postovulatory corpus luteum’. The ovaries undergo a regular annual cycle which has been divided into five stages, based on various criteria, viz, ovarian size, colour, gonosomatic index, average ova‐diameter, histological composition, and the spawning activity.
Infection of estuarine fish populations by Cryptocotyle lingua (Creplin)
Authors: van den Broek W. L. F.
Published: January 2006

Fish populations in the Medway Estuary become infected with Cryptocotyle lingua (Creplin) shortly after their inshore migrations. The present study examines infection levels between 1973 and 1975 in four fish species; whiting, Merlangius merlangus (L.), pouting, Trisopterus luscus (L.), plaice, Pleuronectes platessa L. and flounder, Platichthys flesus (L.). Frequency of infection was highest in flounder, followed by pouting, plaice and whiting. Unusually, parasite density was lowest in plaice even though gastropod molluscs (the parasite's first intermediate host) were most common in their diet. Seasonal levels of infection are discussed and prove useful indicators to the migratory movements of individual fish populations. In whiting and pouting, incidence of infection increased with length of host while no relationship between infection and age of host was observed in either flatfish. Metacercariae were not distributed randomly over the body surface; in gadoids they were concentrated above the lateral line while in pleuronectids they were most intense in the fins and gills.
Different modes of swimming of the carp, Cyprinus carpio L.
Authors: Kashin S. M. , Feldman A. G. , Orlovsky G. N.
Published: January 2006

An electromyographical study has been made of carp swimming muscles at various points along the body length during sustained and burst locomotion. During sustained swimming, red muscles show a constant time lag between activation of anterior and posterior segments which is practically independent of the speed of locomotion. In contrast, anterior and posterior homolateral segments are activated simultaneously during bursts of rapid movement. This pattern of co‐ordination between body segments differs from that reported for other species.
Enzyme activities in the plasma of rainbow trout, Salmo gairdneri Richardson; the effects of nutritional status and salinity
Authors: Sauer D. M. , Haider G.
Published: January 2006

The levels of lactate dehydrogenase, hydroxy butyric dehydrogenase, glutamic oxalacetic transaminase, glutamic pyruvic transaminase, glutamate dehydrogenase, alkaline phosphatase and leucine amino peptidase were determined in the plasma of rainbow trout. The protein concentration and the amount of alkaline phosphatase were reduced in starving trout. Fed trout showed reduced lactate dehydrogenase activity. There was a significant correlation between the condition factor, most of the enzyme activities and the protein concentration. At 10 parts per thousand salinity the activities of alkaline phosphatase and leucine amino peptidase were significantly elevated, while lactate dehydrogenase activity was significantly decreased.
The biology of filter feeding teleosts in Lake St Lucia, Zululand
Authors: Blaber Stephen J. M.
Published: January 2006

The biology of filter feeding teleosts in St Lucia, was studied for two years from 1976 to 1978. The three common species, Gilchristella aestuarius, Hilsa kelee and Thryssa vitrirostris were studied with the composition and cyclical nature of the zooplankton which formed their food. Stolephorus commersonii and Hepsetia breviceps which were rare were only briefly examined. The zooplankton was dominated by the calanoid Pseudodiaptomus stuhlmanni which formed > 70 % of the calorific value of the zooplankton for 70 % of the study period. The mysid Mesopodopsis africana was second in importance in terms of calorific contribution while the amphipod Grandidierella lignorum was relatively abundant. Larval forms, particularly post‐veligers of Assiminea bifasciata were also important. There was a close correlation between the zooplankton cycles, both diel and annual, and the feeding, reproduction and recruitment of the three common filter feeding teleosts. G. aestuarius spent its whole life‐cycle in the system and spawned in early summer when the resulting juveniles could feed on the summer zooplankton peaks. They grew at 0.5 cm month−1 and attained maximum size in one year. They were non‐selective taking mainly P. stuhlmanni and post‐veligers. H. kelee spawned in the sea and juveniles were common in St Lucia during 1978 when they fed non‐selectively, chiefly on P. stuhlmanning the summer before disappearing over the winter. The resulting offspring went through a sequence of dietary changes which were closely related to zooplankton cycles. The importance of P. stuhlmanni in the pelagic food web of St Lucia is illustrated. The species supports not only the filter feeding teleosts but indirectly the predatory fish Argyrosomus hololepidotus and Elops machnata which feed on G. aestuarius and T. vitrirostris.
The immune response of the brown trout, Salmo trutta, L. to MS2 bacteriophage: immunogen concentration and adjuvants
Authors: O'Neill J. G.
Published: January 2006

The humoral antibody response to single intraperitoneal inoculations of MS2 bacteriophage was followed in Salmo trutta using a 50% bacteriophage neutralisation litre (sd50) method. Immune memory was observed with enhancement of both the time and level of antibody production, though an initial suppression was observed 7 days after secondary inoculation. Antibody titres were related to MS2 concentration, and adjuvants were found to enhance the response. An increased enhancement of antibody production by Freund's complete adjuvant over that of incomplete adjuvant was observed.
Influence of social rank on the behaviour of bluegill, Lepomis macrochims Rafinesque exposed to sublethal concentrations of cadmium and zinc*
Authors: Henry M. G. , Atchison G. J.
Published: January 2006

The influence of social rank on changes in Lepomis macrochirus behaviour brought about by exposure to sublethal concentrations of cadmium and zinc was studied. Significant changes occurred in the frequency of eight of the nine behavioural acts quantified. The effects of metals on the behaviour of individuals was often related to the individual's social status in the hierarchies that had formed. The majority of agonistic behaviours (nips and nudges) were performed by dominant individuals and the majority of comfort behaviours (coughs, yawns, jerks, jerk swimming, fin flickering and chafes) occurred in subordinate individuals. These differences occurred during the control period as well as the treatment period and are thought to be in part caused by socially induced stress.
The effect of porcine calcitonin on plasma calcium in Channa punctatm Bloch
Authors: Mathur Reena
Published: January 2006

The effect of porcine calcitonin on the plasma calcium of the freshwater Indian murrel, Channa punctatus Bloch has been studied. An injection of 200 MRC mU of porcine calcitonin was given intraperitoneally, while control fish received the gelatin carrier. A significant hypocalcaemia was noted I h after calcitonin treatment (P < 0.001). The plasma calcium had returned to the normal level by the 6th h.
Haematological assessment of the effects of the anaesthetic MS 222 in natural and neutralized form in three freshwater fish species: interspecies differences
Authors: Smit G. L. , Hattingh J. , Burger A. P.
Published: January 2006

Interspecies haematological differences to MS 222 and neutralized MS 222 anaesthesia were investigated in Sarotherodon mossambicus, Cyprinus carpio and Salmo gairdneri acclimated under identical laboratory conditions. Anaesthesia with MS 222 resulted in a ‘chemical stress’ in all fish, as was evident from changes in the haematological profiles of the animals. Such species specific variations in the haematology persisted throughout the whole experiment protocol which employed different concentrations of the anaesthetic. The use of neutralized MS 222, whereby aquarium water quality remained unchanged, improved the haematological profile. Possible reasons for the interspecies differences observed are discussed.
The effect of dissolved oxygen and salinity on the toxicity of ammonia to smolts of salmon, Salmo salar L.
Authors: Alabaster J. S. , Shurben D. G. , Knowles G.
Published: January 2006

The survival of Atlantic salmon smolts on exposure to constant concentrations of ammonia has been measured under laboratory conditions. At concentrations of dissolved oxygen close to the air‐saturation value, the 24‐h LC50 of un‐ionised ammonia is 0.15 mg NH31−1 in fresh water (hardness 264 mg 1−1 as CaCO3) and 0.3 mg NH31−1 in 30% sea water; at concentrations of dissolved oxygen of 3.5 mg 1−1 in fresh water and 3.1 mg 1−1 in 30% sea water, the 24‐h LC50 is 0.09 mg NH3 1−1 and 0.12 mg NH3 1−1 respectively; for fish acclimated for 1 day to a concentration of ammonia close to the 24‐h median for un‐acclimated fish, the median is increased between 38 and 79%, depending on test conditions.