bluuebunny/crossref_metadata_2025 huggingface dataset:
Structure, histochemistry and the effect of handling on the mucous cells of the epidermis of the char Salvelinus alpinus (L.)
Authors: Pickering Alan D. , Macey D. J.
Published: January 2006

The structure and histochemical characteristics of the epidermis of the char Salvelinus alpinus (L.) were studied at the light microscope level. Sialic acid‐containing glycoproteins appear to form the main components of the mucous or goblet cells. A single incidence of handling can significantly increase the concentration of superficial goblet cells in the epidermis. Repeated handling results in a maximal response after 1 week but this is reduced to control levels after 1 month. These results are interpreted in terms of the structure of the char epidermis.
Haematological parameters of an air‐breathing mud eel, Amphipnous cuchia (Ham.) (Amphipnoidae; Pisces)
Authors: Mishra N. , Pandey P. K. , Datta Munshi J. S. , Singh B. R.
Published: January 2006

Haemoglobin concentrations, haematocrit values, red blood cell counts, red blood cell diameter, erythrocyte sedimentation rate and plasma haemoglobin concentration were measured on the air‐breathing mud eel Amphipnous cuchia.
The fish populations in inshore waters of the West Coast of Scotland. The distribution, abundance and growth of the whiting (Merlangius merlangus L.)
Authors: Gordon J. D. M.
Published: January 2006

The whiting (Merlangius merlangus) is an important commercial species from the West Coast of Scotland. This paper describes the distribution, abundance, age composition and growth of juvenile whiting which are found in the inshore areas and sea lochs. No spawning was observed in the areas and it is assumed there was an active migration of whiting from the open sea. They were first caught by the bottom trawl in July, reached maximum abundance in November and December and thereafter declined in numbers until few remain by early summer. An exception to this occurs in Loch Etive and possible explanations for the fact that whiting tend to remain for longer periods and grow at a slower rate in this loch are discussed.
Effects of heavy metals on development of the killifish, Fundulus heteroclitus
Authors: Weis Judith S. , Weis Peddrick
Published: January 2006

When F. heteroclitus embryos were exposed to inorganic mercury at concentrations of 0.03 or 0.1 mg/1 at the early blastula stage, the percentage of successful axis formation was reduced and a significant proportion of embryos developed cyclopia or intermediate conditions leading to cyclopia. Treatment at the late blastula stage reduced the severity of the defects. Embryos which developed in lead at concentrations of 1 and 10 mg/1 were normal in appearance until hatching, at which time they exhibited lordosis or were unable to uncurl from the position they had while still inside the chorion. No significant effects of cadmium at concentrations up to 10 mg/1 were noted.
Daily ration of adult perch, Perca fluviatilis L. during summer in Loch Leven, Scotland
Authors: Thorpe J. E.
Published: January 2006

Adult perch, Perca fluviatilis L., were sampled at 3‐hourly intervals throughout 24‐h periods from June‐September 1971, and in June and August 1972. The wet weight of each major food component from the stomachs was expressed in parts per 10 000 of the fresh weight of the fish. From samples at capture, and others taken from caged fish at known time‐intervals after capture, the rate of stomach evacuation was estimated. Food consumption between netting times was calculated as the increment between successive initial values of stomach contents, plus the amount evacuated in the interval. As the evacuation rate of caged fish was slower than that of free fish the estimates of food turnover are minimal ones. The perch were consuming 6.5 % of their wet body weight per day in June, and this ration had decreased to 3.2% by September.
The fish populations of inshore waters of the west coast of Scotland. The unusual occurrence of the blue whiting (Micromesistius poutassou) and some notes on its biology
Authors: Gordon J. D. M.
Published: January 2006

This paper records the unusual occurrence of the blue whiting (Micromesistius poutassou) from inshore waters of the west coast of Scotland from 1971 to 1974. The fish were O and I‐group and appeared to migrate into the area during the autumn and winter months. Data on growth, length for weight relationships and feeding are described.
Studies on the toxicity of cadmium to the three‐spined stickleback Gasterosteus aculeatus L.
Authors: Pascoe D. , Mattey D. L.
Published: January 2006

Cadmium was found to be lethal to sticklebacks at all concentrations from 100.0 to 0.001 mg Cd 1–1, in water of 103–111 mg 1–1 hardness as CaCO3. The pattern of mortality as shown by the time‐concentration curve suggests that toxicity is not due to a single mechanism but changes with concentration. Fish were found to accumulate cadmium, the whole body levels increasing from 0.90 μg/g fresh weight at 0.001 mg Cd 1–1 exposure concentration to 51.0 μg/g at 100 mg Cd 1–1. The concentration factor was shown to decrease with increasing exposure concentration from 0.51 at 100 mg Cd 1–1 to 511 at 0.001 mg Cd 1–1. The plerocercoid parasite Schistocephalus solidus in the host's perivisceral cavity contained less cadmium than the tissues of its host.
The abundance and distribution of Diphyllobothrium dendriticum (Nitzsch) and D. ditremum (Creplin) in the char Salvelinus alpinus (L.) in Sweden
Authors: Henricson Jan
Published: January 2006

A total of 654 char, Salvelinus alpinus (L.) and 33 brown trout, Salmo trutta L., were examined for the plerocercoids of Diphyllobothrium dendriticum (Nitzsch, 1824) and D. ditremum (Creplin, 1825). Only char were found to be infected. Both parasitic species were abundant. The incidence and mean intensity of infection for D. dendriticum were 83.2% and 8.8, respectively; for D. ditremum 93.7% and 45.0. There was no variation in the intensity of infection between different parts of the lake. The incidence and intensity of infection increased with the age of the fish to age 8+ for both species. From this age the intensity of infection leveled off or decreased. No differences in intensity of infection between the sexes were found. The frequency distribution of parasite counts were overdispersed and fitted the negative binomial distribution even within single age‐groups. The two parasite species showed a high positive correlation in intensity of infection, D. ditremum was concentrated in the stomach and pyloric caeca. D. dendriticum was more widely distributed within the host and was supposed to kill heavily infected fish.
Studies on the small grey mullet Liza malinoptera (Valenciennes)
Authors: Vino Ching Chong
Published: January 2006

The growth of Liza malinoptera, which is analysed by its morphometric and length–weight relationships, is found to follow closely the so‐called cubic law for isometric growth. The relative condition factor Kn is used to investigate the condition cycle and for maturity studies. Fecundity and ova size are estimated. The fish is a herbivorous iliophage utilising mainly mangrove plant detritus at the first trophic level. Fine particle selection is demonstrated during feeding. Studies on the morphology and histology of its alimentary tract indicate an adaptive correlation with its food and feeding habits.
Reproductive biology, length‐weight relationship and relative condition of Tilapia leucosticta (Trewavas) in Lake Naivasha, Kenya
Authors: Siddiqui Abdul Q.
Published: January 2006

In Lake Naivasha Tilapia leucosticta (Trewavas) spawns throughout the year. Males attain maturity at 180 mm and females at 160 mm total length. Males predominate over females in the catches (sex ratio 1‐00 : 0‐51). Fecundity ranged from 320 to 1328 eggs with an average of 751. The relationship between fecundity (F) and total length (L), body weight (W) and gonad weight (GW) is:

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The length‐weight regression coefficient is near to the cube. There is little seasonal fluctuation in relative condition of the fishes.
Some effects of demersal trawling in Lake Malawi (Lake Nyasa) from 1968 to 1974
Authors: Turner J. L.
Published: January 2006

Exploratory trawl data were used to define demersal fish stocks of Lake Malawi in terms of abundance by depth and area. The mean weight of the catch generally declined with increasing depth. A comparison of initial standing stock estimates and the yield from a commercial fishery over a 7 year period suggests a potential yield of less than half of the initial stock. Over 160 species of fish have been identified in the trawl catch of which over 80% by weight were cichlids. Some of the commonest species of cichlids are listed. The composition of the catch in the heavily exploited southern end of the lake has changed from one dominated by large species of Haplochromis sp. and Lethrinops sp. to one dominated by smaller species.
The plerocercus of Grillotia erinaceus as a biological tag for haddock Melanogrammus aeglefinus in the north sea and north‐east Atlantic
Authors: Lubieniecki B.
Published: January 2006

Analyses of the incidence and intensity of infestation with Grillotia erinaceus plerocerci in 8228 Melanogrammus aeglefinus indicate two distinct groups of haddock at Faroe, and three groups in the area to the north and west of Scotland. In the North Sea the following four groups were recognized: (1) in the Moray Firth and (2) to the north and east of Shetland where, in both groups, incidence of infestation was consistently high; (3) an intervening area where incidence was considerably lower up to three years of age, after which it increased to about the same level as in groups (1) and (2); and (4) in the central North Sea where incidence was consistently low. Changes in the pattern of infestation with host age and with host length within single age‐groups, when considered together with conventional tagging data, suggest that many 3+ and older haddock may migrate from Scottish inshore waters via the Shetland area to the north‐eastern North Sea. The results support other studies in suggesting a northward movement of haddock along the Scottish east coast.
The return of marked roach (Rutilus rutilus L.) to spawning grounds in Tjeukemeer, The Netherlands
Authors: Goldspink C. R.
Published: January 2006

A reciprocal transplant of marked roach between two spatially separated (3.3 km) spawning grounds is described. The recapture rates on the‘home grounds‘were higher than those obtained elsewhere in the lake, which suggests that the roach exhibit a degree of fidelity to specific spawning grounds.
Enzyme activities in the serum of rainbow trout, Salmo gairdneri Richardson; the effects of water temperature*
Authors: Sauer D. M. , Haider G.
Published: January 2006

Activities of lactate dehydrogenase, hydroxy butyric dehydrogenase, glutamic oxalacetic transaminase, glutamic pyruvic transaminase, glutamate dehydrogenase, creatinine kinase, alkaline phosphatase, and leucine amino peptidase were determined in the sera of rainbow trout. The animals had previously been adapted to temperatures of 3.5, 6, 8, 10, 12.5, 15, 17, 19, 21.5 and 23° C. Most of the enzyme activity increased with the rise in temperature. The activity of alkaline phosphatase decreased in the range 6–19° C, while the changes in the glutamate dehydrogenase activity took a complex course. The results are compared with the findings of other authors.
The population biology of two species of eyefluke, Diplostomum spathaceum and Tylodelphys clavata, in roach and rudd
Authors: Burrough R. J.
Published: January 2006

Infections of roach (Rutilis rutilus), and rudd (Scardinius erythrophthalmus), by the eyeflukes Diplostomun spathaceum and Tylodelphys clavata were studied in a lake over a three year period. T. clavata first appeared at the beginning of the study. Roach were heavily infected by both parasites, whereas the rudd contained very few specimens of either species. A small number of roach‐rudd hybrids were also examined, and appeared to have a susceptibility intermediate between the parental types.

Levels of T. clavata in roach increased throughout the study. This parasite had a life span of a year or less in the fish, and was continuously lost from the population. This loss was balanced by a minor infection period in April/May and a major one extending from August until January. The fish continued to accumulate infections until they reached a size of about 130 mm, but thereafter intensity fluctuated about the level reached.

D. spathaceum infections similarly increased throughout the period of study, and there was a suggestion of a wave of infection in the spring. This parasite has a much longer life span, and levels of infection increased with fish size, only falling in the largest, and therefore oldest, hosts.

The major changes in the parasite populations in the roach were reflected, to a lesser extent, in the rudd. Both species were over‐dispersed, but the data from roach was too heterogeneous to fit to any theoretical models, whereas that from the rudd was found to conform to a Negative Binomial distribution.
Breeding the convict cichlid (Cichlasoma nigrofasciatum) for use in laboratory fish toxicity tests
Authors: Piron R. D.
Published: January 2006

A procedure is described for breeding Convict Cichlid (Cichlasoma nigrofasciatum) tropical fish under laboratory conditions. Three generations of Convict Cichlids were bred successfully using this procedure and there was no significant incidence of deformities from in–breeding to the F3, which contrasts with a high incidence of skeletal deformities observed when Zebra Danio tropical fish were inbred to the F3 generation. The Convict Cichlid is a suitable species for laboratory toxicity testing, particularly studies to assess effects on breeding performance.
Interaction between perch (Perca fltuviatilis), and brown trout, (Salmo trutta)
Authors: Burrough R. J. , Kennedy C. R.
Published: January 2006

A decline in the growth rate of perch in Malham Tarn, Yorkshire, has occurred in recent times. This was found to coincide precisely with the resumption of stocking of brown trout, after a period of several years during which no stocking took place. In the absence of any other known correlating factor, it is suggested that the increase in population density of the trout may be responsible for the observed decline in perch growth.
Parasitology of the English Sole, Parophrys vetulus Girard in Oregon, U.S.A.
Authors: Olson R. E.
Published: January 2006

A total of 877 juvenile English sole (Parophrys vetulus Girard) from the Yaquina Bay estuary and742 juvenileandadultsole from the Pacific Ocean off Oregon were examined forparasites. Fifteen species of parasites were found in juvenile English sole on the estuarine nursery ground. Differences in the prevalence and intensity of parasite infection between size classes of juvenile sole and between sole occupying the upper and lower estuary were determined. An additional 14 parasite species were found in offshore English sole, bringing the total observed in all fish to 29 species. Parasites acquired only in the estuary included the microsporidan Glugea stephani, the acanthocephalan Echinorhynchus lageniformis, and the nematode Philometra americana. Those acquired only in offshore areas included the trematodes Otodistomum veliporum and Zoogonus dextrocirrus, the leech Oceanobdella sp. and three species of copepods. An attempt to use parasite data to indicate the presence of distinct English sole stocks along the Oregon coast was inconclusive.
Predator‐prey behaviour of fathead minnows, Pimephales promelas and largemouth bass, Micropterus salmoides in a model ecosystem
Authors: Sullivan J. F. , Atchison G. J.
Published: January 2006

The predator‐prey behaviours displayed by largemouth bass, Micropterus salmoides and fathead minnows, Pimephales promelas, were investigated. Fathead PRMOWS were subjected to predation by largemouth bass and observed in a model system that was designed to mimic a natural ecosystem. Anti‐predator devices utilized by fathead minnows include schooling, surface swimming, formation of a circular aggregation, and seeking refuge under vegetation.
A seasonal study of the haematology of wild freshwater fish
Authors: van Vuren J. H. J. , Hattingh J.
Published: January 2006

Various haematological values of wild yellowfish (Barbus holubi), carp (Cyprinus carpio) and two species of mudfish (Labeo umbratus and Labeo capensis) were examined on a seasonal basis from May 1975‐April 1976, obtained from three different localities. Haematological values of fish of different length groups (from all four species) were studied at one locality during winter only. (June 1976‐August 1976). Seasonal variations were observed in all of the parameters studied but no sexual differences were found and no significant changes in the haematology could be related to breeding season. Wide individual variations were evident in fish of different length groups and no correlation existed between fish length (and mass) and haematological values.
Age and growth determination in a marine catfish using an otolith check technique
Authors: WarBurton K.
Published: January 2006

A direct and accurate method of age determination using the relative positions of otolith growth checks is described. In the catfish Guleichthys cuerulescens, otolith length and depth were both linearly related to fish length. Checks appeared to be formed twice per year, at the beginning and at the end of the rainy season (late June to late September). Growth was more rapid in the wet season, when water temperatures were at their height. Calculated mean fork lengths of spring‐spawned fish after the first four years of life were respectively 11.5, 19.3, 26.3 and 33.1 cm. Few individuals grew beyond 40 cm, the survival of most of the population being five years or less, but a maximum recorded length of 51.5 cm suggested that catfish may occasionally persist into their seventh or eighth year. The shape of the growth curve indicated that, since a permanent seaward migration of older fish is unlikely, then natural mortality among lagoon‐resident G. cuerulescens occurs before a growth asymptote is reached.
The parasite fauna of resident char Salvelinus alpinus from Arctic islands, with special reference to Bear Island
Authors: Kennedy C. R.
Published: January 2006

Samples of resident freshwater char, Salvelinus alpinus were obtained from three lakes on Bjørnøya and their parasite faunas examined. Comparison of the species composition, number, diversity and equitability of the parasite faunas of Bjørnøya with those of other Arctic islands, an inshore island and lakes on the Norwegian mainland indicated that the communities on Bjørnøya formed a distinct unit with a high degree of similarity between the three lakes. Small differences could be related to differences in the ecology of the lakes. The parasite community of char on Spitsbergen showed the greatest similarity to that on Bjørnøya, and the communities of char in mainland lakes the least. Species number and diversity of parasites were often higher on the Arctic islands than on the mainland, and did not correlate with island size or distance from the mainland. The island parasite communities were often dominated by a single species, but a similar situation was also observed in the mainland lakes. It is concluded that the parasite fauna of char on offshore Arctic islands does not agree well with the predictions of island biogeographical theory.
Trigger or file‐fish (Balistes carolinensis) in Irish waters
Authors: Went A. E. J.
Published: January 2006

Until the year 1947 only two specimens of B. carolinensis had been recorded from Irish waters but from 1947 to 1976 no less than 81 specimens were examined, a large number of which, 32 or 39.5% of the total, in the year 1975 (Table I). The geographical distribution of the specimens shown in Fig. 1 indicates that from the Mayo coast northwards and around to Wexford trigger‐fish are rarely taken. The distributions by month (Table II) and length groups (Table III) are also given, together with the relationship between fork lengths and weights (Fig. 2).
Comparison of ‘Pseudobranch’ type and ‘Chloride’ type cells in the pseudobranch of marine, freshwater and euryhaline teleosts
Authors: Mattey D. L. , Moate R. , Morgan M.
Published: January 2006

The degree of similarity between the ‘pseudobranch type’ and ‘chloride type’ cells in the pseudobranch of bass (Dicentrachus labrax (L)), smelt (Osmerus esperlangus) and rainbow trout (Salmo gairdneri) was studied. The pseudobranch of bass and smelt contains two specialised cell types commonly known as ‘chloride type’ and ‘pseudobranch type’ cells, whereas rainbow trout only possess the latter type. ‘Pseudobranch type’ cells are characterised by the orderly arrangement of parallel tubules around their closely packed mitochondria. ‘Chloride type’ cells are identified by their highly branched tubular network, randomly distributed mitochondria, and the presence of an apical pit. Although ultra‐structural changes were noted under osmotic stress, the ‘chloride type’ and ‘pseudobranch type’ cells remained distinguishable from each other and gave no reason to suggest that they were different forms of the same cell type. It was concluded that the two are distinct cell types, performing different, though possibly related, functions.
Observations on development and morphological effects of histamine liberator 48/80 on PAS‐positive granular leukocytes and heterophils of Catostomus commersoni
Authors: Barber D. L. , Westermann J. E. Mills
Published: January 2006

Developmental stages of the two circulating blood granulocytes, the heterophil and the periodic acid‐Schiff‐positive granular leukocyte (PAS‐GL) are described. There are no metachromatic basophils in this fish and eosinophils, when present, are confined to extra‐vascular tissues. Fish were killed up to 24 h after injection with histamine liberator 48/80. Morphological (L/M and E/M) and histochemical studies of blood, haemopoietic tissue and gills from experimental fish were compared with those of untreated control fish.

Blood cells other than PAS‐GL and heterophils were generally unaffected by 48/80. Most PAS‐GL and heterophils showed alterations in granules and other cytoplasmic features. Stretching and splitting of the PAS‐GL nucleus occurred. Very little, if any, histamine was detectable in PAS‐GL and heterophils.

The authors support the postulate that during evolution PAS‐GL become basophils/ mast cells through two major stages, (1) sulphation of the granule polysaccharide to give heparin resulting in metachromasia of the granules and (2) storage of large quantities of histamine in the granules.
The production of brown trout, Salmo trutta in tributaries of the Upper Wye, Wales
Authors: Milner N. J. , Gee A. S. , Hemsworth R. J.
Published: January 2006

The population density, age structure, biomass, growth and production of brown trout were investigated in four tributaries of the upper River Wye. The populations at each site were largely maintained by immigration from nursery areas. Abundance of separate year classes at sites on the three largest tributaries reached a peak at age 2+. On the smallest stream numbers reached a peak at 1+. Recruitment occurred throughout the year but decreased with age of year classes. Maximum O+ densities ranged from 0.04 to 0.89 m−2, and >0+ densities from 0.13 to 0.59 m−2. Average total biomass in 1975 ranged from 2.6 to 14.2 g m−2. Within the study sites annual trout production in 1975 ranged from 2.9–19.7 g m−2. Production values were dependent on age structure and population mobility at the study sites. In the three largest streams 2+ and 3+ fish contributed 66.3–88.3% of total production whilst 1+ and 2+ fish contributed 74.5–84.5 % of the total in the smallest stream. The mobile (non‐resident) component of the population accounted for up to 60–70% of production at certain times of the year, but over the year (1976) accounted for =30 % of total production. The resident component of the highest annual production value (19.7 g m−2) was estimated to be between 15.0 and 18.2 g m−2.
Particulate and filter feeding in threadfin shad, Dorosoma petenense, at different light intensities
Authors: Holanov S. H. , Tash J. C.
Published: January 2006

Previous workers inferred from stomach analyses that threadfin shad (Dorosoma petenense) ate plankton by both filter and particulate feeding. These inferences were confirmed in this study by laboratory experiments in which both types of feeding were observed. Threadfin shad consumed relatively small food particles (≤ 0.39 mm) by filtration, while larger prey (7.5 mm) were eaten individually. The shad were able to filter feed on small foods (brine shrimp nauplii and phytoplankton) at all light intensities from 0 to 9 × 101 fL. These data indicate that under natural conditions shad can filter feed at any time of the 24 h period if food conditions are sufficient to trigger feeding. Filter feeding is probably induced by chemoreception rather than vision. The particulate feeding rate decreased as light intensity decreased, reaching a minimum between 9 × 10−4 and 9 × 10−5 fL. From these data it is inferred that particulate feeding is a visual process in this species, requiring intensities equivalent to bright moonlight or greater. Filter and particulate feeding abilities allow threadfin shad to consume most of the different types of plankton and to change their diet with seasonal changes in the composition of the plankton.
The use of telemetry to study light synchronization with feeding and gill ventilation rates in Salmo trutta
Authors: Oswald R. L.
Published: January 2006

A technique is described whereby the electromyogram of the m. adductor mandibulae of brown trout is detected by implanted extracellular electrodes and used as the input signal for an ultrasonic transmitter attached externally to the fish. The periodic electrical activity of the muscle during ventilation is relayed by the transmitter using an analogue pulse system.

As the ventilatory electromyogram occurs in discrete rhythmic trains, it follows that alterations to this rhythm can be used to telemeter, instantaneously, single feeding events from a free swimming fish. Laboratory tests have shown that the feeding act is unequivocally distinct electromyographically from other manoeuvres such as ‘coughing’.

Four adult brown trout have been equipped with this transmitter system and released in Airthrey Loch, Stirling. Using a tracking facility, feeding activity and ventilatory rhythms have been recorded for extended periods.

The results indicate the presence of three daily peaks of feeding activity, which is discussed in relation to changes in light levels. The telemetry records indicate that night feeding is a common occurrence in brown trout. In addition, ventilatory rates were found to be at or near resting levels.
The effects of pinealectomy on pituitary and plasma gonadotropin levels in Carassius auratus exposed to various photoperiod–temperature regimes
Authors: Vodicnik Mary Jo , Kral Roman E. , de Vlaming Victor L. , Crim Larry W.
Published: January 2006

The effects of pinealectomy on pituitary and plasma gonadotropin levels and gonadal development in female goldfish exposed to various photoperiod‐temperature regimes during different seasons were examined. Pinealectomy during autumn had no effect on either pituitary or plasma hormone levels or gonadal development. When goldfish are pinealectomized in spring and exposed to long photoperiod conditions, the ovaries regress and plasma gonadotropin levels are significantly depressed compared to sham operated animals. Sham operated goldfish exposed to short photoperiod conditions in spring had regressing ovaries whereas pinealectomized animals under this regime either spawned or had ovaries in the late vitellogenic phase. Plasma gonadotropin titres in the pinealectomized group were significantly lower than those of sham operated animals. The pineal can be either stimulatory or inhibitory to gonadal development depending on the photoperiod regime to which the animals are exposed. The pineal apparently influences gonadal activity by modulating gonadotropin secretion. A diurnal variation in plasma gonadotropin levels was also observed in both sham operated and pinealectomized goldfish exposed to a long photoperiod warm‐temperature regime in spring.
Histopathological changes in fish gills infected with myxosporidian parasites of the genus Henneguya
Authors: Dykova I. , Lom J.
Published: January 2006

Tissue reaction to invasion by two Henneguya species was studied in gills of three species of fish. Henneguya psorospermica and Henneguya creplini develop in secondary lamellar arterioles in perch (perca fluviatilis) and ruff (Acerina cernua). In pike (Esox lucius), H. psorospermica develops in the artery. During the growth of the vegetative stage, the gill tissue may undergo local atrophy or hyperplasia of the epithelium and displacement and disfiguration of the lamellae. After the myxosporidian cyst, surrounded by a host tissue capsule has reached maturity and contains fully‐formed spores, an inflammatory reaction may set in which reduces the cyst to granulomatous tissue. This inflammatory process is essentially of the same type as that observed in mammals. There is evidence that inflammatory responses are of regular occurrence in the final stages of most myxosporidian infections. Transfer from low to room temperature provokes a rapid elimination of the cysts by granulomatous inflammation.
The biology, specificity and habitat of the species of Eubothrium (Cestoda: Pseudophyllidea), with reference to their use as biological tags: a review
Authors: Kennedy C. R.
Published: January 2006

The literature pertaining to the distribution, habitat, specificity, life cycles and population biology of all the species of Eubothrium is reviewed. Records in which scolex morphology is used to identify species cannot be used as this character is too variable to be of value in specific recognition. Study of the valid records suggests that E. crassum comprises three races. There is a freshwater race, whose preferred host is non‐migratory Salmo trutta fario, but which also infects parr, smolts and landlocked adult S. salar and parr of migratory S. trutta trutta. Its distribution is confined to Europe and Eurasia and is co‐extensive with that of S. trutta: it does not occur in N. America or E. Asia. It may be carried to sea in migratory salmonids, where it dies out in S. salar but may survive in S. trutta. Its life cycle only takes place in fresh water, and requires a copepod as the only intermediate host. Other fish species may serve as paratenic or accidental hosts. The preferred host of the marine Atlantic race of E. crassum is S. salar, but S. trutta is also infected. Its distribution is co‐extensive with that of S. salar on both sides of the Atlantic Ocean. It may be carried into fresh water by both hosts, when its numbers decline in S. salar but not in S. trutta. The life cycle is unknown, but infection probably takes place in marine coastal waters. The preferred hosts of the marine Pacific race are all species of Oncorhynchus, with which its distribttion is co‐extensive on both sides of the Pacific Ocean. It may also be carried into fresh water, and its life cycle is also unknown. E. salvelini comprises two races. The European freshwater race is specific to Salvelinus alpinus, and does not infect Salmo spp. Its life cycle takes place in fresh water and involves only one intermediate host, a copepod. It may be carried to sea in migratory fish, and survive to return to fresh water. The American race, found throughout North America and East Asia, infects species of Salmo, Salvelinus, Oncorhynchus, Cristivomer and other genera. Its biology is otherwise similar to that of the European race, although its return from the sea has not yet been confirmed in America. The other species of Eubothrium are more local in their distribution, some being endemic; do not comprise different races, and infect marine and anadromous fish. Nothing is known of their biology or life cycle. Eubothrium is recognised as being a marine genus that has invaded fresh water with anadromous fish. The inability to distinguish the races of E. crassum and E. salvelini on morphological characters, their low rate of survival in the other medium and their wide distribution renders them unsuitable as biological tags.
Observations on the ecology of Clinostomum marginatum in largemouth bass (Micropterus salmoides)
Authors: Hazen Terry C. , Esch Gerald W.
Published: January 2006

Over a fifteen month period, beginning October, 1974, approximately 13 500 centrarchids were examined for evidence of infection with metacercaria of Clinostomum marginatum. Species checked included Lepomis macrochirus, L. gulosus, L. auritus, Pomoxis nigromaculatus and Micropterus salmoides. The study site was Par Pond (South Carolina, U.S.A.), an 1120 ha reservoir receiving thermal effluent from a nuclear production reactor. Except for the largemouth bass, M. salmoides, infection percentages among the five species were less than 1%. Among bass, infection varied seasonally, being highest from January to June. From the spring highs of approximately 25 %, the percentages dropped to lows of < 10% in July and August; there was a jump in September‐October to another peak of 30% and then a steady decline through December when infection percentages were again less than 10%. Neither body condition nor length of the bass were related to infection percentage or metacercaria density. Infection percentage could not be related to the influence of thermal effluent. Infection percentages did vary from location to location within the Par Pond system. A significant rank correlation could be established between infection percentage and the amount of littoral zone present in the locality from which the bass were taken. It is suggested that the local ‘bay effects’ are the result of limited home and foraging ranges of the bass in relation to the amounts of littoral zone present in various locations of the reservoir.
Swimming activity of perch, Perca fluviatilis L.
Authors: Alabaster J. S. , Stott B.
Published: January 2006

The swimming excursions of individual perch, measured automatically, within either cages in Windermere or in a trough on the shore, showed increases at dawn and dusk and in the summer. Similar measurements in troughs in the laboratory showed increased activity following a change from light to dark and vice versa, a pattern that was obliterated by either continuous light or continuous darkness. These results are discussed in relation to water temperature and catches of perch in traps.
Rhythmic growth activity in fish scales
Authors: Ottaway E. M.
Published: January 2006

Changes in the growth of fish are reflected in the rate of growth of their scales. This produces the rings used in ageing temperate species. A technique has been devised for measuring the rate at which [14C] glycine is incorporated into isolated scales in vitro. This method has been used to investigate various rhythmic activities in fish growth. The results show that the amino acid is incorporated into at least two types of cell and that deposition in the scale occurs with at least two different rhythms with very different frequencies.
The physiological response of fishes to a deficiency of cyanocobalamin and folic acid
Authors: John M. J. , Mahajan C. L.
Published: January 2006

Environmental adaptive response of fishes to the nutritional deficiencies of two important vitamins of the B‐group viz. cyanocobalamin and folacin has been investigated using growth, haematology and haemopoiesis as physiological indices. Extended studies lasting 105 days revealed a consistent decrease in growth or even loss of weight when cyanocobalamin and folacin were absent from the diet. The combined deficiency of these two vitamins had an additive rather than synergistic effect on growth. The feed conversion values of all the deficient groups were significantly low as compared to the control. Haematologically the occurrence of anaemia and leucocytosis were recorded in all the deficient groups, the former mainly of megaloblastic type. Differential WBC counts revealed that leucocytosis was mainly due to an increase in thrombocyte population and cosinophils. On the other hand, there was an relative decrease of other nongranulocytes and granulocytes. Erythro‐poietic investigations revealed a decreased proliferation rate of the reticuloendothelial cells and an increased number of young and mature reticulocytes and immature erythrocytes into the peripheral blood.
Changes in growth and size distribution of Sarotherodon macrochir and Sarotherodon andersoni from the Kafue Floodplain, Zambia, since construction of the Kafue Gorge Dam
Authors: Dudley Richard G.
Published: January 2006

The Kafue floodplain produces an annual fish yield of about 5000 tonnes. The 1971 closure of the Kafue Gorge Dam downstream from the floodplain modified flooding patterns and created some question as to whether conditions for growth and reproduction of major species would be adversely affected or improved. No obvious changes in the growth of the two major species, Sarotherodon andersoni and S. macrochir, that could be related to the dam were found in samples collected in 1975. Available data concerning year class fluctuations and size distribution indicate that typical high post‐impoundment water levels may limit reproduction and year class size of these Sarotherodon species.
A note on the existence of a well‐developed swimbladder in the bottom‐living goby Pomatoschistus minutus
Authors: Hesthagen I. H. , Koefoed Jens H.
Published: January 2006

The swimbladder in the sand goby, Pomatoschistus minutus, collected in shallow waters of the Oslofjord, Norway, was studied. As the literature on swimbladders in gobies appeared to be confusing, a short review of relevant literature has been made. On average, the volume of the swimbladder in the sand goby expressed as percentage of the body weight was found to be 4·7 % in May and 2·5 % in June. The significance of this volume variation is discussed.
Spatial distribution and feeding in atlantic salmon, Salmo salar L. juveniles
Authors: Wańkowski J. W. J. , Thorpe J. E.
Published: January 2006

The distribution, social behaviour, and feeding behaviour of juvenile Atlantic salmon were studied in a selection of stream and river habitats in northern Scotland using Scuba diving techniques. The results are discussed with respect to food acquisition and choice of feeding site. It is concluded that juvenile salmon feed predominantly on drifting material and that their daytime distribution reflects the current velocity related abundance of drift.
Morphology and histochemistry of the caudal gland of Corynopoma riisei Gill
Authors: Atkins D. L. , Fink W. L.
Published: January 2006

Males of the South American freshwater fish, Corynopoma riisei, have glandular masses on the caudal peduncle and fin which are partly enclosed by a scale‐covered pouch. Histo‐chemical examination reveals an extensive layer of large secretory cells superficial to the dermis appearing similar in form to typical mucous cells. PAS and Alcian blue staining indicate all cells produce muco‐ and/or glycoproteins and that a few cells are also synthesizing mucopolysaccharides. This secretion probably acts as a pheromone during courtship to stimulate or release female sexual response.
Parasites of marine sticklebacks
Authors: Dartnall H. J. G. , Walkey M.
Published: January 2006

A total of three specimens of Spinachia spinachia and 11 Gasterosteus aculeatus were caught in Loch Etive, Scotland. The salinity of the water at the capture site was 23%. Nine species of parasites were collected from individuals of the mixed population of sticklebacks, which included seven new parasite records for the British Isles.
Cell types in the peripheral blood of an air‐breathing fish Channa punctatus
Authors: Mahajan C. L. , Dheer Jagmohan Singh
Published: January 2006

Different cell types found in the peripheral blood of Channa punctatus, an air‐breathing freshwater fish have been characterized and identified using morphological, morphometric, cytochemical and autoradiographic techniques. Some of the cytochemical methods used, particularly that of differential staining of haemoglobin have been developed and used for the first time in fishes.
A note on the age composition, growth rate and food of perch Perca fluviatilis (L.) in four eutrophic lakes, England
Authors: Goldspink C. R. , Goodwin D.
Published: January 2006

The perch populations of all lakes sampled are characterised by high growth rates (l± 320–410 mm) and year‐class instability. The concurrence of four year‐classes (1970,1973,1975and 1976) in three of the lakes is good evidence for climatic control of recruitment. Poor recruitment in Rostherne Mere during 1973 is attributed to the effects of cannibalism. An increase in the growth rate of young fish (0+) in all lakes during 1975 and 1976 is noted. The relatively poor growth of perch in Rostherne Mere is a consequence of the low specific growth rate there during the first year of life. An outbreak of the ‘perch‐disease’ killed most of the adult perch present in 1975 in Rostherne Mere.
Reproductive cycles of two Australian freshwater fishes: the spangled perch, Therapon unicolor Gunther, 1859 and the East Queensland rainbowfish, Nematocentris splendida Peters, 1866
Authors: Beumer J. P.
Published: January 2006

The reproductive cycles of the spangled perch Therapon unicolor Gunther, 1859 and the East Queensland rainbowfish Nematocentris splendida Peters, 1866 are described in terms of maturity stages, sex‐ratio, gonosomatic indices, oocyte diameters, fecundity and rearing experiments. T. unicolor has a well‐defined reproductive cycle with gonad development stimulated by rising temperatures and increasing daylength; with spawning induced by the ‘wet’, possibly by rising water levels and increasing turbidities. In contrast, N. splendida has a protracted spawning period with a peak of spawning activity in pre‐flood and flood periods, although individuals in spawning condition and juveniles may be found throughout the year.
Host specificity of the parasite fauna of perch Perca fluviatilis L. from the British Isles, with special reference to a study at Llyn Tegid (Wales)
Authors: Andrews C.
Published: January 2006

Five‐hundred and fifty‐nine perch (Perca fluviatilis L.) were examined from Llyn Tegid between January 1975‐July 1976 for protozoan and metazoan parasites. Sixteen species of parasites were recorded, and these results were compared to previous studies at Llyn Tegid, and elsewhere in the British Isles. It was concluded that the parasite fauna of perch is influenced by the diversity and abundance of the local aquatic invertebrate fauna, the local ichthyofauna, the local piscivorous avian fauna and the history and geographic isolation of the environment. The importance of a large series of observations on a variety of habitats was stressed.
Relationship of environmental pCO2 to selected blood parameters of Oncorhynchus kisutch (Walbaum)
Authors: Bubien J. K. , Meade T. L.
Published: January 2006

Blood samples from sub‐adult coho salmon (Oncorhynchus kisutch) were correlated with environmental conditions. Carbon dioxide tensions, pH and bicarbonate levels were determined in the blood for fish acclimated to environmental pCO2 levels of 2.49 and 2.74 mmHg. Fish were removed from the high pCO2 environment and placed in one with a low pCO2. Their blood pH and pCO2 were monitored during the course of acclimation. After 27 days of acclimation to a low pCO2 environment, a group of fish was sampled and compared to a group of fish acclimated to a high pCO2 environment. It was found that pCO2 in the environment affects the rate of diffusion of carbon dioxide from the blood to the water. Under the environmental conditions prescribed in these experiments no significant change in bicarbonate was noticed. It is postulated that a bicarbonate chloride exchange is not a major pathway for the removal of carbon dioxide from the blood of O. kisutch.
The adaptation of digestive enzymes to temperature, season and diet in roach, Rutilus rutilus and rudd Scardinius erythrophthalmus; Proteases
Authors: Hofer R.
Published: January 2006

The seasonal changes of proteolytic activity in the gut content of roach R. rutilus and rudd S. erythrophthalmus in four Tyrolean lakes and the adaptation of the proteases to constant temperatures and different natural diets were studied. In rudd proteolytic activity remains nearly constant throughout the year. In roach proteolytic activity increases and then decreases during the first three months after the thaw in spring. This period appears to be endogenously controlled and is followed by a second stage in which proteolytic activity is influenced by environmental factors. Under natural conditions both species have a higher proteolytic activity when feeding on animals than on detritus. Under laboratory conditions there is a slight maximum at an environmental temperature of 16° C when the fish had been fed on meal worms. With plant food a significant dependence of proteolytic activity on environmental temperature was only found in roach.
Selective predation on Cladocera by brown trout Salmo trutta L.
Authors: Fltzmaurice P.
Published: January 2006

The size and species composition of zooplankton ingested by brown trout in Lough Sheelin was studied. Zooplankton and fish samples were taken simultaneously. The zooplankton samples consisted of Daphnia hyalina var. galeata, Copepoda and Bythotrephes longimanus in the proportion of 246: 10: 1. The entire stomach contents of the fish were examined with particular attention paid to the zooplankton component. The results indicated a high degree of selection for B. longimanus.
Aggressive behaviour of juvenile brown trout Salmo trutta, L: an analysis of the wigwag display
Authors: North E.
Published: January 2006

The wigwag display of the juvenile brown trout (Salmo trutta, L) was analysed and found to be a ritualised display used specifically as a defensive manoeuvre in the aggressive interactions of groups of fish. Wigwag displays performed against fish of lower or equal social rank were highly effective as a defence but wigwags performed against higher ranking fish were less than 50% effective.
‘Pear‐shaped’ cells in the digestive tract of the perch Perca fluviatilis (L.)
Authors: Hirji K. N. , Courtney W. A. M.
Published: January 2006

Light and electron microscopy revealed the presence of ‘pear‐shaped’ cells amongst the mucosal cells of the stomach, pyloric curvature, pyloric caeca and the anterior‐most region of the intestines of perch. The cells are usually located in the distal region of the mucosa and are approximately half the height of the other mucosal cells. Electron microscopy shows that the cells are composed of thick outer sheaths which are fibrillar in appearance. The cytoplasm is characterized by electron dense rods numbering from three to fifteen, which originate from the supranuclear region of the cells and converge apically. The rest of the cytoplasm is composed of Golgi apparatus, secretory vacuoles, minute mitochondria and a network of cytoplasmic strands laden with ribosomes. The organization of organelles in these cells does not resemble that of other mucosal cells of the alimentary canal. Contrary to what has been suggested previously, the ‘pear‐shaped’ cells neither resemble nor represent stages in the formation and maturation of goblet cells.