bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of food on the growth of carcase, liver and ovary in female Gasterosteus aculeatus L.
Authors: Allen J. R. M. , Wootton R. J.
Published: January 2006

The effect of ration size on the growth of the carcase, liver and ovary in female three‐spined sticklebacks, Gasterosteus aculeatus L., was studied experimentally at monthly intervals throughout the annual reproductive cycle. Temperature and photoperiod during each experiment corresponded to the average, natural conditions for that month.

Growth of the carcase was sensitive to ration in all months. At a given ration, the growth rate of the carcase was relatively constant. The water content of the carcase was inversely correlated with ration size. Growth of the liver was also sensitive to ration, but the sensitivity varied in different phases of the reproductive cycle. High rates of weight loss occurred in the liver under starvation, but at maximum rations the liver showed high rates of weight gain particularly in the post‐spawning period. Growth of the ovary was relatively insensitive to ration but directly reflected the changes occurring naturally in the reproductive cycle.

It is suggested that the liver acts as a buffer between the carcase and the ovary and this helps to insulate the ovary from the immediate effects of fluctuations in food supply.

The growth rates of the carcase and liver may provide useful indices of the rate of food consumption in natural populations. Although, if the liver is used, its growth has to be interpreted in the context of the annual reproductive cycle.
Changes in the skin‐scale complex with sexual maturation in the European eel, Anguilla anguilla (L.)
Authors: Pankhurst N. W.
Published: January 2006

Structural features of the epidermis, dermis and scales were examined in adult female Anguilla anguilla of varying sexual maturity. Advanced sexual stages were obtained by hormone injection. The dermis increased in thickness with both size and sexual development. Epidermal thickness was unrelated to size or maturity but mucous cell densities decreased in more mature animals. Hormone treated eels showed a loss of mucous cells accompanied by degeneration of the epidermis. Scale areas increased from 50% in sexually immature adults to 145% in sexually maturing eels. Skin calcium values ranged from 0.27 to 0.83 mg cm−2 and did not show any relation to either scale or sexual maturity. The possible relevance of structural changes to migration is discussed.
The fecundity of mullet (Pisces, Mugilidae) from Cuban waters
Authors: Alvarez‐Lajonchere L.
Published: January 2006

The fecundities of Mugil liza, M. hospes, M. curema and M. trichodon from Cuban waters were determined volumetrically. The subsamples obtained with a Bogorov pipette from a saturated salt solution had a coefficient of variation (C.V.) of 6.81% and did not introduce a bias. Since the fecundity‐weight relationships were significantly different between species and between M. curema from different localities, this character might be used to discriminate between species and stocks of mugilids. There was the same ranked order for fecundity and growth rate of the different species; M. liza had the highest values followed by M. curema, M. hospes and M. trichodon..
A new species of the deep‐sea eel genus Ilyophis Gilbert (Synaphobranchidae) from the eastern North Atlantic, with comments on its ecology and intrafamilial relationships
Authors: Saldanha L. , Merrett N. R.
Published: January 2006

A new species of synaphobranchid eel, Ilyophis blachei, is described from the eastern North Atlantic. It is distinguished by 179–188 vertebrae, dorsal fin inserted half (or more) of the snout length posterior to extended tip of pectoral fin, gill slits obliquely inclined anteroventrally from pectoral base, rounded posterior nostril bordered anteriorly by conspicuous triangular flap, long lateral line (87–95% S.L.), supraorbital canal pores 5–6, infraorbital 7–8 and preoperculomandibular 10–11, supraorbital and supratemporal commissures with 1 and 3 pores, respectively. The diagnosis of the genus Ilyophis is extended to embrace these characters. The transitional position of the genus between the subfamilies Synaphobranchinae and Dysomminae is discussed in the light of this new evidence. Ilyophis blachei occurs on the lower continental slope (1247–2070 m soundings) within the temperature range c. 7.0−3.3°C. The first record of I. arx in the Atlantic Ocean is also reported.
On remembrance of the abdominal pores in rainbow trout, Salmo gairdneri Richardson, and some other salmonid spp.
Authors: George C. J. , Ellis A. E. , Bruno D. W.
Published: January 2006

Direct connections (abdominal pores) between the peritoneal cavity and the external environment of elasmobranch fishes and some teleost species including the Salmonidae were recognized almost 100 years ago but over this period their existence in these teleost species has been omitted from anatomical texts. In this report, the abdominal pores of rainbow trout, Salmo gairdneri, Atlantic salmon, Salmo salar, and the cisco, Coregonus artedii, were examined in relationship to ip injected particulate material. Both carbon particles and suspensions of the bacterial kidney disease organism were found to be extruded within masses of macrophages and as free particles through the abdominal pores in fish injected ip 72 h previously. The pores were patent in male and female, mature and immature fish. The role and significance of the abdominal pores in rainbow trout in the clearance from the body of material, including material likely to be used for vaccinating fish, is discussed.
Observations on the gall bladder of juvenile Atlantic salmon Salmo salar L., in relation to feeding
Authors: Talbot C. , Higgins P. J.
Published: January 2006

Measurements of gut contents and changes in the volume and colour of bile in the gall bladder of juvenile Atlantic salmon are described for a variety of feeding regimes. The gall bladders of actively feeding fish are virtually empty of bile. When deprived of food, the weight of the gall bladder increases within 6 h and reaches a value equivalent to approximately 20% of the liver weight within 36 h. Bile is pale straw, green and blue in colour after 1, 4 and 6 days of starvation respectively. Stored bile is released from the gall bladder in response to food entering the anterior hind gut.
Association of an acoustic signal with operant conditioned feeding responses in thicklipped mullet, Crenimugil labrosus (Risso) and common carp, Cyprinus carpio (L.)
Authors: Wright D. E. , Eastcott A.
Published: January 2006

Groups of both carp, Cyprinus carpio, and mullet, Crenimugil labrosus, learned to associate a 250 Hz sine wave generated acoustic singnal with a previously conditioned trigger pressing operant response for food. Within 48 h, a programmed signal of 5 min duration in every 1 h period was stimulating trigger responses for food reward, whilst during other periods not associated with sound there were few responses.
Notes on the biology of the Patagonian hake, Merluccius hubbsi (Marini), the southern blue whiting, Micromesistius australis (Norman) and others in the Falkland Islands shelf area
Authors: Stott F. C.
Published: January 2006

From the examination of samples of fish caught in two commercial surveys on trawling grounds around the Falkland Islands, it is noted that Patagonian hake, Merluccius hubbsi, southern blue whiting, Micromesistius australis, and others occurred in fishable quantities especially to the east of Beauchêne Islands where fishes were larger and more numerous. However 47% of the total catch consisted of southern blue whiting which was 100% infested by a myxosporidian parasite in its musculature rendering it unsuitable for human consumption.
Direct and circulatory paths of Permethrin (NRDC‐143) causing histopathological changes in the gills of rainbow trout, Salmo gairdneri Richardson
Authors: Kumaraguru A. K. , Beamish F. W. H. , Ferguson H. W.
Published: January 2006

Rainbow trout were exposed to sublethal concentrations of Permethrin in water (0.09, 0.18 and 0.35 μg l−1) and in food (85, 180 and 350 μg kg−1 dry diet) in 20–0 day experiments. Histological changes in the gills included epithelial separation or necrosis, mucus cell hyperplasia, clubbing of epithelial cells or hyperplasia and fusion of adjacent secondary lamellae. These changes were noted in all fish, suggesting that the pesticide or its metabolites reached the gills not only directly through the water, but also indirectly via the circulation.
The effect of feeding 11‐ketotestosterone on the food conversion efficiency and tissue protein and nucleic acid contents of juvenile carp, Cyprinus carpio L.
Authors: Lone K. P. , Matty A. J.
Published: January 2006

Juvenile common carp were fed 11‐ketotestosterone for 60 days with the diet and the effect on food conversion efficiency, organ weights and protein and nucleic acids (RNA, DNA) content of the liver, kidney, brain and muscle were observed. Feeding of the steroid increased the food conversion efficiency of all the experimental groups studied as compared with controls. A decrease in weight of brain, liver and kidney in relation to body weight was noticed after 60 days of the hormone feeding. No change in the visceral weight was observed. These changes in relative weights of the organ were ameliorated 30 days after the withdrawal of the steroid from the food. The weight of the viscera decreased compared with the control weight during this time. Feeding of the hormone brought variable changes in the total proteins, RNA/DNA, protein/RNA and protein/DNA in all the organs studied. In addition to these findings, changes in the moisture, total lipid and ash contents of the muscle were also observed. The results are discussed in the light of existing knowledge of the effect of anabolic‐androgenic steroids on the growth processes of different organisms.
A histological study of development of oocytes in capelin, Mallotus villosus villosus (Müller)
Authors: Forberg K. G.
Published: January 2006

Female capelin, Mallotus villosus villosus, were sampled at various times of the year from the Barents Sea and preserved for histological examination. The current paper describes various stages of development of capelin oocytes. The description can be used as the basis for the preparation of a maturity scale to be used in the field, using whole oocytes and low power microscopy. The development of the oocytes is classified into 10 stages according to morphological characters. First growth phase oocytes are always present in the ovaries, showing that female capelin have a potential for several spawnings. Second growth phase oocytes grow synchronously. Oocytes of‘ Yolk vesicle stage I‘ are suggested to be the first stage of second growth phase which lasts for somewhat less than one year, and ends with spawning.
Recovery of the brown trout, Salmo trutta L., from acute handling stress: a time‐course study
Authors: Pickering A. D. , Pottinger T. G. , Christie P.
Published: January 2006

The response of the brown trout to a single, short (c. 1 min) incidence of handling stress was monitored for a period of 1 month post‐stress. Significant changes were found in feeding behaviour, in the levels of plasma cortisol, glucose and lactate, in the concentration of circulating lymphocytes and in the degree of epidermal mucification. No changes were detected in the growth rate and coefficient of condition, in the levels of plasma thyroxine, in the concentrations of circulating erythrocytes, neutrophils and thrombocytes or in the thickness of the epidermis. The time‐course for recovery of each parameter was examined and from this it was concluded that a minimum of 2 weeks was required for complete recovery and a return to normality.
The activity of myofibrillar and actomyosin ATPase in the skeletal muscle of some marine teleosts in relation to their length and age
Authors: Witthames P. R. , Walker M. Greer
Published: January 2006

The activity of myofibrillar ATPase declined with length in the five species examined (Merlanogrummus aeglefinis L., Merrluccius merluccius L., Physis blennoides Brunnich, Pleuronectes platessa L. and Merlangius merlangus L.). This decline was related to a decrease in the in vitro muscle contraction rate and appeared to be a scale rather than an age effect. Actomyosin was extracted from Merlangius merlangus L. to investigate the length related changes in the myofibrillar protein.
The maximum sustainable yields of the inshore fish and shrimp resources of the Nigerian continental shelf
Authors: Ajayi T. O.
Published: January 2006

Schaefer's and exponential models are used to predict the maximum sustainable yields (MSY) of the Nigerian inshore fish and shrimp resources. The MSY values for fish caught down to 40 and 50 m were 11684·09 and 13742·35 metric tonnes (t), respectively. For shrimp, the MSY estimated was 2008·02 t. It appeared that the inshore fishery still had room for expansion, but the shrimp resources seemed to be fully exploited under the prevailing circumstances.
Some aspects of the biology of a cyprinid, Aspius vorax Heckel
Authors: Shafi M. , Jasim B. M.
Published: January 2006

Scales were used for the determination of age with back‐calculation of length. The oldest fish was VII + years old. Back‐calculation did not exhibit Lee's phenomenon. The most rapid growth occurred in summer at water temperatures over 25°C. The growth in weight was c. 331 g year‐1 after IV vears of life. Growth was well described by von Bertalanffy equation : ll ‐ 91·0 [l=0·122(l0·25)] The length‐weight relationship followed the cube law (b = 3·0601) Kn ranged from 0·74 to 1·18 with a mean value of 1·0. Spawning occurred in January, fecundity was 74 509 with a mean of 1157 eggs ‐1 body weight. Mean diameter of eggs was 1071 (pm). A developed ovary had ova of two sizes, immature oocytes and mature ova. The fish is a carnivorous feeder.
Duration of gut passage and its dependence on temperature and food consumption in roach, Rutilus rutilus L: laboratory and field experiments
Authors: Hofer R. , Forstner H. , Rettenwander R.
Published: January 2006

A laboratory method is described by means of which gut passage time as a function of temperature, diet and consumption rate is investigated in roach, an omnivorous cyprinid. Rates of food passage are accelerated by increasing temperature and food consumption. Equations for the regressions between gut passage time and consumption rate at four temperatures are given. Animal food causes a delay in gut passage time. In adult roach (30‐100 g body weight) gut passage time was found to be independent of size.

A field method was also developed which allows the direct estimation of gut passage time and consumption rate in natural fish populations. The results of experiments with this field method agree with those of laboratory experiments.
Some aspects of sustained training of rainbow trout, Salmo gairdneri Richardson
Authors: Nahhas R. , Jones N. V. , Goldspink G.
Published: January 2006

Groups of 6‐7 cm length rainbow trout, Salmo gairdneri Richardson, were simultaneously trained at four water velocities (0, 1·4, 2·2 and 3·5 Ls‐1) for a period of 46 days. Oxygen consumption and swimming ability (fatigue time) were then measured. Only training at 3·5 Ls‐1 increased the swimming ability of the fish. A study of the relative proportion of the white and red muscles indicated that the white muscle was increasing its mass at velocities in excess of 2·2 Ls‐1. The oxygen consumption rate of the trained fish was lower than that of the untrained fish when considered over the whole velocity range.
Skin mucus protease from rainbow trout, Salmo gairdneri Richardson, and its biological significance
Authors: Hjelmeland K. , Christie M. , Raa J.
Published: January 2006

The skin mucus of rainbow trout, salmon, charr, cod, coalfish, plaice and redfish contain, besides lysozyme and haemagglutinins, protease activity. The mucus protease from rainbow trout has been purified, characterized and shown to be indistinguishable from the trypsin produced in pylorus caecae. This enzyme activity can escape detection in mucus since it is inhibited by serum components which may contaminate the skin mucus as a result of stress and handling of the fish prior to collecting the mucus.
Growth gradients in fish larvae*
Authors: Fuiman L. A.
Published: January 2006

Relative growth intensity of various longitudinally measured body segments in larvae of several species of fishes was distributed across the body in a continuous, U‐shaped gradient. Juveniles lacked a simple pattern of growth but appeared to grow nearly isometrically. Body depth exhibited a shallow, U‐shaped gradient while body width lacked a discernible pattern. Most intense growth, in three orthogonal planes, occurred posteriorly, probably promoting effective swimming early in life.
Seasonal variations in the lipid composition of the steelhead trout, Salmo gairdneri Richardson, associated with the parr‐smolt transformation
Authors: Sheridan M. A. , Allen W. V. , Kerstetter T. H.
Published: January 2006

Total lipid and lipid class composition of selected tissues and serum were determined for juvenile steelhead trout Salmo gairdneri, during the smolting period between 25 January and 19 April 1982. The total lipid content of the serum, liver, light muscle and dark muscle was significantly depleted during smolt transformation. Mesenteric fat total lipid concentration fluctuated little over the sampling period. Phospholipids of muscle and mesenteric fat exhibited little seasonality. Cholesterol was significantly depleted from dark muscle and liver. Large stores of triacylglycerol (TGL) in the parrs' mesenteric fat, dark muscle and liver implicate these tissues as lipid depot organs. In those tissues depleted of lipid, TGL concentrations were reduced more than any other lipid class. This supports the hypothesis that increased catabolism is the cause of loss of body fat during salmonid smolt transformation.
The lateral musculature of the common bully, Gobiomorphus cotidianus, a freshwater fish from New Zealand
Authors: Davison W.
Published: January 2006

A histochemical and ultrastructural study has shown that the myotome of the common bully, Gobiomorphus cotidianus, is composed of three muscle fibre types: white, pink and small diameter fibres. There are no red fibres. Both white and pink fibres have characteristics similar to these fibres found in other teleosts. The small diameter fibres are located in the position usually occupied by red fibres and are identified by their small size and poor staining characteristics. At the ultrastructural level these small fibres are seen to have few mitochondria and a poorly developed sarcoplasmic reticulum. It is suggested that the small diameter fibres are a type of tonic muscle used for positioning the trunk.
Changes in vision and olfaction during sexual maturation in the European eel Anguilla anguilla (L.)
Authors: Pankhurst N. W. , Lythgoe J. N.
Published: January 2006

Retinal structure was examined in sexually immature and artificially matured female Anguilla anguilla. Inner nuclear layer cell numbers decreased from 600 mm−1 retinal cross‐section to 300 mm−I and ganglion cells from 60 to 30 mm−1 cross‐section, during sexual maturation. Most of the decrease occurred prior to the stage of maturation at which migration begins. Electroretinograms were recorded from the intact eyes of immature and maturing eels. There was no change in scotopic sensitivities to light of wavelengths 480 and 520 nm, with increasing sexual maturity. Olfactory organs were examined in female eels of a similar range of maturity states and were found to atrophy in artificially matured eels of advanced development. The density of mucous cells in olfactory lamellae decreased from a maximum of 443 mm−2 in sexually immature eels to as low as 19 mm−2 in sexually maturing eels. The changes in vision and olfaction were thought to indicate a change in the relative importance of the two sensory modalities with sexual maturation.
Tolerance to gas supersaturation in fresh water and sea water by steelhead trout, Salmo gairdneri Richardson
Authors: Bouck G. R. , King R. E.
Published: January 2006

The euryhaline status of steelhead trout, Salmo gairdneri, smolts was challenged in sea water for 2 weeks after which half of the total fish population was returned to fresh water. Acclimation continued and created two test populations in 29%osea water and fresh water. Subsequently these fish were exposed in fresh water or sea water to approximately equal hyperbaric dissolved total gas pressures (ΔP) of 190 mm Hg or about 125% of barometric pressure. Sea water was easier to supersaturate with air and required only about 10% of the entrained air which was required in fresh water at the same temperature and pressure. Mean time to first mortality was sooner in sea water. Mean times to mortality (10–50%) were not significantly different between fresh water and sea water, but there was a noticeable trend for longer survival in fresh water.
Thermal ecology of the mudskippers, Periophthalmus koelreuteri (Pallas) and Boleophthalmus boddarti (Pallas) of Kuwait Bay
Authors: Tytler P. , Vaughan T.
Published: January 2006

The annual range of body temperatures (14–35°C) of emergent mudskippers are substantially less than that of air temperatures (10–42°C) as a result of behavioural thermoregulation. In winter, low surface temperatures are avoided by remaining in burrows. Newly emerged mudskippers then bask until body temperatures rise above 14°C before they move onto the mud. In summer, body temperatures are kept lower than ambient by selecting areas where evaporative cooling is high. Body temperatures generally match those of wet mud, which can be 7°C lower than air shade temperatures. The smaller, more terrestrial, Periophthalmus koelreuteri have body temperatures which are mainly lower in summer and higher in winter than Boleophthalmus boddarti.
Pinealectomy and ovarian development in the grey mullet, Liza ramada
Authors: Sagi G. , Abraham M. , Hilge V.
Published: January 2006

Adult female specimens of Liza ramada were pinealectomized and sham‐pinealectomized, and the development of their ovaries was followed over a period of 14 weeks and compared with those of untreated controls. Pinealectomized specimens exposed to long photoperiod (16L/8D) for 14 weeks, showed undeveloped ovaries, with a maximum oocyte diameter of less than 100 μm, and a gonadosomatic index of 0·6 similar to that of sham‐pinealectomized and control specimens. In pinealectomized females exposed to short photoperiod (8L/16D) for 6 weeks, the mean diameter of oocytes was 270 μm v. 155 μm in control and sham‐pinealectomized specimens. After 9 weeks, the oocytes in pinealectomized specimens reached 430 μm as against 265 μm in the controls. Within 14 weeks of pinealectomy, mean oocyte diameter was 480 um while it was 400 μm in controls and sham‐pinealectomized specimens. It is tentatively concluded that the pineal complex has an inhibitory effect on ovarian function in Liza ramada exposed to short photoperiod.
Effect of dietary quality on the gastric evacuation and intestinal passage in Sarotherodon mossambicus (Peters) fry
Authors: De Silva S. S. , Owoyemi A. A.
Published: January 2006

The gastric evacuation time (GET) and the passage of food through the intestines was investigated in Sarotherodon mossambicus (Peters) fry of two size groups, viz. 0·2–1·0g and 1·0–3·0g, in response to five diets. In the experiments voluntary feeding was adopted and markers were not used. The passage of food through the stomach was described by the exponential model.

The GET increased with body weight for any particular diet, with one exception. The GET ranged from 290 min to 1104 min in fry of 1·0–3·0 g on Diet 2. There was evidence to indicate that the GET was negatively correlated to the specific gravity of the diet.

The passage of food through the intestines showed a consistent trend from diet to diet; e.g. the algal diet being moved into the intestine in ‘finite’ quanta as opposed to the others. The importance of these observations and the implications of the dependence of the GET on the specific gravity of the diet in the use of markers in digestibility studies are discussed.
Implications of testicular constrictions on spermatogenesis in Lake Ontario lake trout, Salvelinus namaycush
Authors: Ruby S. M. , Cairns V.
Published: January 2006

This study examines the histological significance of a testicular anomaly among hatcheryraised lake trout, Salvelinus namaycush, introduced into Lake Ontario as yearlings and subsequently recaptured at ages ranging from 4 to 7 years. The anomaly has been termed a constriction. Histological examination revealed that lake trout with constricted testes demonstrated delayed cycles of spermatogenesis throughout the testes at spawning time compared with normal testes. Constrictions were formed when spermatogonia within an adjacent group of lobules failed to undergo mitosis, hypertrophied and were subsequently resorbed. The walls of these lobules subsequently collapsed and were resorbed and replaced by dense fibrous connective tissue. The significance of these observations in relation to hormonal mechanisms and its potential effect upon reproduction in these fish is discussed.
The pathology of Chilodonella hexasticha (Kiernik). Infections in cichlid fishes
Authors: Paperna I. , Van As J. G.
Published: January 2006

Pathological and histopathological changes induced by infection of Chilodonella hexasticha (Kiernik) in wild and cultured cichlid fishes from Israel and South Africa are described. Heavy infection resulted in emaciation and mass mortalities. Infection in the gills caused severe degeneration, necrosis and consequent degradation of the branchial epithelium and occlusion of the capillaries. Infection also induced massive proliferation of chloride and mucus cells and also caused hyperplasia of the lining filamental epithelium. However, epithelial hyperplasia was counteracted by the extreme process of degradation of the epithelial layer and as a result was either limited in extent or occurred in an uneven pattern.
Variations in renal corpuscular morphology with adaptation to sea water in the rainbow trout, Salmo gairdneri Richardson
Authors: Colville T. P. , Richards R. H. , Dobbie J. W.
Published: January 2006

The kidneys of similar sized rainbow trout from freshwater and seawater environments were examined and several parameters of renal corpuscular morphology were measured, The glomeruli of the seawater trout were significantly smaller and contained significantly fewer red blood cells than those of the freshwater fish. There was also some evidence of a decreased number of renal corpuscles per unit area, and an increased proportion with no apparent capsular space in the seawater trout.
Sensory cues and mechanisms involved in the capture of euphausiids by the Australian salmon, Arripis trutta (Bloch & Schneider)
Authors: Morgan W. L. , Ritz D. A.
Published: January 2006

Experiments indicated that the initial detection of euphausiid prey by Arripis trutta is visual with the cues being shape and/or movement. Immediately before capture of prey in midwater, swimming speed of the fish increased from 15 to 33 cm s−1. The sequence of morphological events during capture is similar to that described for suction feeding in other teleosts such as Atlantic salmon Salmo salar. Occasionally prey would be ejected from the mouth after capture by means of a reversal of the mechanism used in suction feeding.
Spawning of the Australian freshwater fish Murray cod, Maccullochella peeli (Mitchell), in earthen ponds
Authors: Rowland S. J.
Published: January 2006

Murray cod, Maccullochella peeli, spawned naturally in earthen ponds in four consecutive breeding seasons. Spawning was induced by a rise in water temperature up to or above 20°C during spring, however, an associated rise in water level was not required. Response to the temperature rise was more rapid later in the season and increasing daylength may have also been involved. Eggs were deposited on firm substrates at depths between 0·5 and 2·3 m, and hollow pipes, logs or similar structures were not necessary to provide suitable sites for egg deposition. At two spawning sites, mud had been removed from the pond banks by the broodfish and the eggs attached to the exposed clay. At one spawning site, a male cod was observed protecting the eggs during incubation.

It is suggested that high survival of cod larvae will only occur when a significant rise in water level coincides with the breeding season and as a consequence the control of water levels for irrigation and flood mitigation purposes during spring and summer has affected Murray cod to a greater extent than golden perch, Macauaria ambigua, which spawns only after a substantial rise in water level, when conditions are more favourable for larval survival.
Epieimeria anguillae (Léger & Hollande, 1922) Dyková & Lom, 1981 (Apicomplexa: Eucoccidia) in the European eel, Anguilla anguilla (L.)
Authors: Lacey S. M. , Williams I. C.
Published: January 2006

Moderate infections with the coccidian Epieimeria anguillae, were found in the intestinal epithelium of European eels, Anguilla anguilla, from one estuarine and two freshwater localities. The morphology and epicellular position of the schizogonous and macrogameto‐gonous stages of the present specimens of E. anguillae confirmed the original, and only previous, description. Sporogonous stages were intracellular. Fully‐developed oocysts ruptured their host cells and compressed neighbouring cells, but no erosion of the mucosal epithelium was seen. The results are discussed in relation to previous studies of E. anguillae and to the threat to farmed eels from a source of infection in wild eels.
Development and growth of laboratory reared Engraulis japonica (Houttuyn) larvae
Authors: Fukuhara O.
Published: January 2006

The development and growth of Japanese anchovy larvae, Engraulis japonica, are described from laboratory‐reared specimens. Fertilized eggs were collected from cultured parental fish. Rotifers, Anemia and copepods were offered to larvae of different sizes. Fin ray formation was completed at 21 mm S.L. Pigmentation during development is described. Newly hatched larvae grew to 29·38 mm standard length in 62 days. The daily length increment averaged 0·43 mm.
The effects of temperature on muscle pH, adenylate and phosphogen concentrations in Oreochromis alcalicus grahami, a fish adapted to an alkaline hot‐spring
Authors: Johnston I. A. , Eddy F. B. , Maloiy G. M. O.
Published: January 2006

The concentrations of phosphorylcreatine (PCr), adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP), inorganic phosphate (Pi), pyruvate and lactate were determined in freeze‐clamped fast muscle samples from Oreochromis alcalicus grahami a fish adapted to extreme alkalinity (∼ pH 10·0) and high temperatures (Lake Magadi, Kenya). Specimens were analysed from both geothermally heated hotsprings (35–37°C) and from isolated cool pools (28°C) and from stocks acclimated to 20°C in the laboratory. The ratios of (ATP)/(ADP) and (ATP)/(ADP) (Pi) decreased with increasing body temperature consistent with an increase in glycolysis and tissue respiration rates, respectively. The apparent equilibrium constant of creatine kinase (KCK), (creatine) (ATP)/(phosphorylcreatine) (ADP) was found to decrease with increasing temperature: 20·2 (20°C), 13·9 (28°C), 8·0 (37°C). A near constant muscle and blood pH (or slight increase in alkalinity with higher temperatures) was found regardless of body temperature (Blood pH 7·64, 7·74, muscle pH 7·27, 7·51 at 20°C and 35°C, respectively). These results are consistent with an unusual pattern of acid‐base regulation in this species.
Food and feeding habits of the lesser spotted dogfish, Scyliorhinus canicula (L.), in Isle of Man waters
Authors: Lyle J. M.
Published: January 2006

Stomach contents of the lesser spotted dogfish, Scyliorhinus canicula, from Isle of Man waters were investigated. Dogfish fed opportunistically on a wide range of macrobenthic fauna with hermit crabs, cockles and whelks the dominant prey. Items of secondary importance included various crabs, callianassid shrimps, bivalve molluscs, holothurians, polychaetes and, when locally abundant, herring, Clupea harengus. Dogfish predated more heavily on molluscs than reported in previous studies, reflecting the abundance of molluscs in the associated benthic community.

Composition of the diet altered gradually with dogfish size, reliance on small crustaceans declined and consumption of hermit crabs and molluscs increased with growth. Seasonal changes in the composition of the diet were observed. Feeding intensity was greatest during summer, related in part to increased prey availability, and was least during autumn.
A new genus and species of rattail fish (Macrouridae) from the eastern North Atlantic and eastern Indian Ocean, with notes on its ecology
Authors: Merrett N. R. , Sazonov Y. I. , Shcherbachev Y. N.
Published: January 2006

A new genus, Macrosmia, and species (M. phalacra) of benthopelagic macrourid fish is described from single male specimens caught in 1650–1699 m soundings in the northeastern Atlantic and south‐eastern Indian Oceans. This elongate macrourine rattail, with 7 branchiostegal and 11–12 pelvic rays, is unique in its massive olfactory organ, the cavity of which almost equals the diameter of the orbit. This cavity is a reverse D‐shape, with the posterior margin deforming the orbital rim into a D‐shape. Macrosmia has a short deep snout, lacks prominent ridges on the head, has anteriorly placed plevic fins and a weakly serrated second spinuous ray in the first dorsal fin. The anus is contiguous with the anal fin. These characters, among others, show affinity with the Cetonurus group of genera. The distribution and diet of the species is briefly discussed and M. phalacra is shown to be at least partly dependent on benthic food which, from one example, is of crustacean origin.
Pheromones and the water source preferences of adult coho salmon Oncorhynchus kisutch Walbaum
Authors: Quinn T. P. , Brannon E. L. , Whitman R. P.
Published: January 2006

It has been proposed that population‐specific pheromones released by juvenile salmonids guide the adults on their homing migration (Nordeng, 1977). To evaluate this hypothesis, adult coho salmon, Oncorhynchus kisutch, were tested in a two‐choice apparatus with a variety of water sources. Coho salmon preferred home water without coho odours over an unfamiliar water source (city water). Adults preferred water conditioned by juveniles of their own population over plain city water, but did not prefer water conditioned by juveniles of their own population over that of another.
Growth in a natural population of largemouth bass, Micropterus salmoides Lacepede, as determined by physical measurements and [14C]‐glycine uptake by scales
Authors: Smagula C. M. , Adelman I. R.
Published: January 2006

Growth of largemouth bass, Micropterus salmoides, in Lake Rebecca, Minnesota began in July and was associated with increased food consumption. Decreased maintenance levels and increased food consumption combined to produce maximum growth in September. Body growth and in vitro [14C]‐glycine uptake by scales varied similarly after the onset of growth; however, during the pre‐growth period, fluctuations in glycine uptake may have reflected physiological changes that were not detected by measurement of scale and body growth, but did relate to feeding activity. Patterns of glycine uptake and scope for growth were positively correlated (r= 0.74, P<0.05), which suggested that uptake may be related to general nutritional state.
Feeding behaviour of yearling and older hybrid grass carp
Authors: Cassani J. R. , Caton W. E.
Published: January 2006

Hybrid grass carp resulting from the cross of a female grass carp, Ctenopharyngodon idella (Val.), and a male bighead carp, Hypophthalmichthys (Aristichthys) nobilis Rich., 12–18 months old (c. 300 mm T.L.) were studied in a two‐part experiment to determine feeding preference and total daily consumption fish‐1 on selected species of aquatic plants. Fish were maintained in circular pools with 6840·8 1 of water inside a temperature‐controlled greenhouse. Preference tests were conducted at three temperature ranges; 25–28° C, 17–20° C and 12–15° C. Based on the time to complete consumption or the relative quantity consumed, the most preferred plant was Lemna gibba when in combination with six other species. Chara sp., Najas guadalupensis and Potamogeton peciinatus were readily consumed and considered to be of about equal preference. Ceratophyllum demersum and Myriophyllum brasiliense were least preferred. Hybrid grass carp generally consumed as much plant material species‐1 and in the same order of preference at the 12–15°C range as they did at 25–28° C. In the second part, mean daily consumption (g) fish‐1 at 25·7–31·0° C for five plant species tested separately was as follows: Chara sp. 369·8; Lemna gibba 178·2; Najas guadalupensis 172·6; Hydrilla verticillata 106·4 and Ceratophyllum demersum 8·8.
Egg‐case diversity among dogfish, Scyliorhinus canicula (L.): a study of egg laying rate and nidamental gland secretory activity
Authors: Mellinger J.
Published: January 2006

Egg‐case size, shape and pigmentation are distinctive features of each female lesser‐spotted dogfish, Scyliorhinus canicula. During 9 months captivity under constant conditions (water, temperature, photoperiod, food), a laying sequence reminiscent of an annual cycle was observed in three females. While oocyte size and (with exceptions) egg‐case weight remained constant, there was a marked decrease of the‘albumen’jelly secreted by the anterior halves of nidamental glands.
Observations on the histology and histochemistry of the oesophagus of the perch, Perca fluviatilis L.
Authors: Hirji K. N.
Published: January 2006

The anatomy and enzyme histœhemistry of the œsophagus of a freshwater teleost perch (Perca fluviatilis L.) has been studied. The mucosa is composed of an undifferentiated layer of basal epithelial cells, mucous cells and surface epithelial cells. The submucosa is compact and contains blood vessels, nerves and bundles of striated longitudinal muscles. The outer circular muscular layer contains both striated and smooth muscle fibres. Electron microscopy shows that the surface epithelial cells are degenerative and that they surround and support pores of the mucous cells. Undifferentiated epithelial cells undergo cytoplasmic changes and eventually become surface epithelial cells. Mucous cells arise from the undifferentiated epithelial cells and their droplets contain acid and neutral mucosubstances. Alkaline phosphatase, non‐specific carboxylic esterases and aminopeptidase activity is absent in the mucosa. However, acid phosphatase activity is localized in the surface epithelial cells.
Why do fish die after severe exercise?
Authors: Wood C. M. , Turner J. D. , Graham M. S.
Published: January 2006

Trout fitted with dorsal aortic cannulae were subjected to 6 min of intensive exercise and monitored over the following 12 h recovery period. Delayed mortality was 40%; the majority of deaths occurred 4–8 h post‐exercise. Surviving fish exhibited a short‐lived haemoconcentration reflected in increased haematocrit, haemoglobin, plasma protein, Na+ and Ch‐ levels; an extended rise in plasma [K+]; a quickly corrected respiratory acidosis; and a more prolonged metabolic acidosis in concert with a rise in blood lactate. Dying fish exhibited very similar trends except for a significantly greater metabolic acidosis, lower plasma [Cl‐], and the apparent accumulation of an unknown anion in the blood prior to death. Cardiac failure did not occur. Blood metabolic acid levels, while elevated, were only ∼ 50% of peak lactate anion levels and well within the normal range of tolerance, as were all other changes observed in the blood of non‐survivors. The hypothesis that post‐exercise mortality is due to excessive ‘lactic acid’ accumulation in the blood is discounted. It is suggested that intracellular acidosis may be the proximate cause of death.
Temporal changes in fat and protein levels in the tropical Anabantid Trichogaster pectoralis (Regan)
Authors: Hails A. J.
Published: January 2006

Samples of a wild population of the Anabantid Trichogaster pectoralis (Regan) were taken during and after one of the two main breeding periods of the year. Carcasses of both sexes and female gonads were analysed for fat, protein and carbohydrate. Carbohydrates were present in insignificant amounts in all tissues. The fat content of the ovary proved to be high (over 30% of wet weight) and, as a result, ovarian energy in a ripe female formed a substantial proportion of the total energy content of the fish. However, it did appear possible for females to develop large ovaries without depleting the carcass fat stores.

Although protein levels in the carcass were significantly higher in 1 month, relative to fat levels, protein levels remained fairly constant during the period of study. Conversely fat levels showed marked fluctuations throughout the breeding period, being high at the start of the breeding period, low towards the end, finally rising again 1 month after most fish had terminated breeding. The range of fat levels appeared to be independent of the gonadal state of the fish at capture and seemed more closely related to month of capture. Two explanations are suggested; (1) changes in food availability over the period in question and/or (2) if repeated spawnings occur this could deplete fat reserves in the carcass.

In this species fat is stored largely in the muscle but some is stored around the coiled intestine. A visual scoring system was used to assess the extent of this fat deposition and it was found that the fat score was correlated with the level of fat in the carcass. Thus the level of fat around the intestine, although insignificant relative to carcass fat, could be used as a method of assessing the fatness of a fish.
A new goby, Glossogobius minutus (Teleostei: Gobiidae) from the south‐west coast of India
Authors: And C. Geevarghese , John P. A.
Published: January 2006

A new species of gobiid fish Glossogobius minutus collected from the south‐west coast of India is described. The morphological, morphometric and meristic characters were studied with special emphasis on osteology. The various characters are compared with those of G. giuris (Harn.) and G. biocellatus (Val.), the only other species of the genus reported from this region. Glossogobius minutus is a benthic omnivore and shows distinct sexual dimorphism.
A new species of the deep‐sea fish genus Coryphaenoides Gunnerus (Macrouridae) from the tropical eastern North Atlantic and its relationship with C. (Coryphaenoides) marshalli Iwamoto, 1970
Authors: Merrett N. R.
Published: January 2006

A new species of macrourid, Coryphaenoides paramarshalli is described from mid to lower slope waters (l 13–160 m) off West Africa, in the area 04°S‐21°N and 10°E‐18°W. The species is very closely related to C. marshalli. Indeed, two of the paratypes of that species are incorporated among the paratypes of C. paramarshalli, as they are referrable to the new species. The features distinguishing the two species are discussed in conjuction with those separating C. paramarshalli from other related species.
The seasonal occurrence of postlarval stages of yellowfin bream, Acanthopagrus australis (Gunther), and some factors affecting their movement into an estuary
Authors: Pollock B. R. , Weng H. , Morton R. M.
Published: January 2006

Planktonic postlarvae of yellow fin bream Acanthopagrus australis were found at surf bar entrances to Moreton Bay, a large subtropical estuarine system on the east coast of Australia. The postlarvae occurred from April to September with peak abundance during July to September. Most postlarvae entered the estuary at night during the full moon. They were more abundant on the flood and full tides than on the ebb tide. The transition from planktonic to littoral existence occurs from August to November when the fish are 13‐14 mm in length. Young yellow fin bream in littoral areas reach a modal length in excess of 100 mm after 1 year.
Influence of body weight and temperature on growth rates of Arctic charr, Salvelinus alpinus (L.)
Authors: Jobling M.
Published: January 2006

When reared for a period of 6 months at a temperature of 10°C Arctic charr, Salvelinus alpinus, increased in weight from 18 g to approximately 135 g. Specific growth rates decreased as the fish increased in size and the relationship between size and growth rate could be described by the equation:

image

where Gw is specific growth rate and W is fish weight in grams. Temperature effects upon growth were examined using previously published data. Below the optimum growth temperature, the growth rate of a fish of given size could be predicted using the equation:

image

where T is the rearing temperature.

Rates of growth of Arctic charr were as high as those reported for other salmonid species reared under similar conditions. Preliminary results suggested that growth rates of charr may be lower in salt water than in fresh water.
Estimating population densities of salmonids in deep water in streams
Authors: Gardiner W. R.
Published: January 2006

Densities of salmon, trout and grayling were assessed in Scottish streams by systematic counting by underwater observers, where the water was greater than 1 m deep, and by using electrofishing equipment in adjacent shallower areas. Tests of the efficiencies of the two methods are described. Applications have included the estimation of production of trout, grayling and young salmon at a site on the River Tay and predicting the salmon smolt run of the River Tilt, and these applications are briefly described. The most suitable period for visual counting was summer, as at water temperatures of less than 15° C fish were hiding among stones in the stream bed. Wet weather hampered both electrofishing and visual counting.
Vascular pathways in the gill filaments of the flounder, Platichthys flesus L.
Authors: Al‐Kadhomiy N. K.
Published: January 2006

This study is concerned with functional organization of some of the blood pathways in the gill filament of the flounder, Platichthys flesus L. The existence of two independent vascular pathways has been confirmed. The blood from the efferent filament artery (EFA) enters the central venous sinus (CVS) through very small blood vessels which are characterized by the presence of sphincter‐like structures. The existence of an independent chamber of the CVS mainly full of white blood cells provides evidence of an independent lymphatic system connected to the CVS. Gill rays support the afferent side of a gill filament whereas plasma and an extensive network of nutritive blood vessels in the CVS supports the efferent part.
The efficiency of a new electrofishing technique in determining fish numbers in a large river in Central Poland
Authors: Mann R. H. K. , Penczak T.
Published: January 2006

A new method of determining fish numbers in a large river, which involved electrofishing from boats downstream to an AC electrical barrier, produced capture efficiencies for different species ranging from 28 to 82% when successive pairs of catches were combined. Estimates of population density, biomass and production for the 18 species in a 2.538 ha segment of the Pilica River, Poland revealed a decline in total numbers of the fish in species diversity between 1963 and 1980. This is attributed to increased fishing pressure, and to a loss in habitat diversity following the loss of many water mills and associated dams. The total production estimate of 0.85 g m−2 year−1 is low compared with the few published estimates for other large rivers. Roach, dace, chub, gudgeon and bream were the most numerous fish and they constituted 75% of the total population estimate, and 68% of the standing crop and annual production.