bluuebunny/crossref_metadata_2025 huggingface dataset:
Temporal patterns in shore fly (Diptera, Ephydridae) community structure in a salt marsh habitat
Authors: Kubátová‐Hiršová Hana
Published: April 2005

Abstract.  1. An ecological investigation of the shore fly community was carried out in a salt marsh in Novosedly in the Czech Republic.

2. Sampling was carried out in 1997 and 1999 at approximately 14‐day intervals during the seasonally active period, using yellow water traps.

3. Altogether 14 374 specimens of the family Ephydridae were collected (6040 in 1997 and 8334 in 1999), belonging to 48 shore fly species (37 in 1997 and 41 in 1999).

4. Community structure, species richness, species diversity, evenness, and seasonal and inter‐annual changes were studied. The species richness, species diversity, and evenness of the shore fly community in 1999 were higher than in 1997 but inter‐annual difference in species diversity was not statistically significant. Paracoenia fumosa, Scatella tenuicosta, and Hydrellia albilabris were found to be the most abundant species in both study years.

5. Seasonal patterns and phenology of the most abundant species are discussed. Hydrellia albilabris showed similar seasonal distribution of abundance in 1997 and 1999, whereas seasonal distribution of P. fumosa and S. tenuicosta varied between the study years. Paracoenia fumosa, Hydrellia griseola, H. albilabris, Scatella paludum, S. tenuicosta, and Philotelma defecta were found to occur throughout the whole observation period from March until November while Notiphila cinerea, Hydrellia ischiaca, and Psilopa nigritella appeared in a limited period only.
Herbivore‐induced responses and patch heterogeneity affect abundance of arthropods on plants
Authors: Rodriguez‐Saona Cesar , Thaler Jennifer S.
Published: April 2005

Abstract. 1. Plants respond to herbivore damage by inducing defences that can affect the abundance of herbivores and predators. These tritrophic interactions may be influenced by heterogeneity in plant neighbourhood.

2. In the present study, the effects of induced responses on the abundance of herbivores (flea beetles and aphids), omnivores (pirate bugs and thrips), and predators (lady beetles and spiders) on individual plants and their neighbours between and within patches composed of three tomato plants was investigated.

3. Herbivore damage was manipulated to create homogeneous patches where either all or none of the plants had defences induced by herbivore damage, and heterogeneous patches where only one of the plants was induced.

4. Arthropod abundance on plants at different scales was compared by testing between patch effects (patch level), for neighbourhood effects at the plant phenotype level (neighbourhood level), and between near and far plants (within patch position).

5.At the patch level, plants in homogeneously induced patches contained fewer flea beetles and pirate bugs, but more lady beetles, compared with homogeneously non‐induced patches. There was no effect of patch type on the abundance of aphids, thrips, and spiders on plants.

6.At the neighbourhood level, induced plants in heterogeneous patches contained more flea beetles and pirate bugs compared with induced plants in homogeneous patches, indicating that the abundance of some herbivores and omnivores on induced plants varied depending on the phenotype of the other plants within the patch. Within patch position, there was no evidence that the abundance of herbivores or predators on non‐induced plants was affected by proximity to an induced plant.

7. Therefore, variation in plant neighbourhood generated by induced plant responses affected the abundance of three arthropods from three feeding guilds.
Community structure of insect herbivores in a hybrid system: examining the effects of browsing damage and plant genetic variation
Authors: Hochwender Cris G. , Janson Eric M. , Cha Dong Ho , Fritz Robert S.
Published: April 2005

Abstract. 1. Using three genetic classes of willows,Salix eriocephala,Salix sericea, and their interspecific F1 hybrid, the influence of browsing damage and the importance of genetic class on insect community structure were evaluated.

2. Three‐year‐old plants grown from seeds generated from controlled crosses were placed in a common garden after a damage treatment was imposed on them (plants were either left undamaged during the previous winter or they had 50% of the previous year's growth removed). Clipping damage caused large increases in mean shoot length for plants.

3. The abundance of eight species of insect herbivores was determined for every plant to evaluate community structure for three genetic classes across the two damage levels. Based onmanova, damage treatment had a modest effect on the relative abundance of herbivores (i.e. their proportional representation). In contrast, dramatic differences were detected among genetic classes for relative abundance; in cases where damage treatment influenced relative abundance of herbivores, the importance of genetic class was at least 20‐fold greater than that of damage treatment. No interaction between genetic class and browsing treatment was detected for community structure.

4. The weak response of the herbivore community to clipping damage, contrasted to the large response to genetic class, was very surprising because mean shoot length was greatly altered by damage treatment. These findings, coupled together with previous research, suggest that plant genetic differences can act as the primary basis for herbivore community structure, while the effects of browsing may not be as common.
Mitochondrial DNA variation in Atlantic salmon, Salmo, salar L., populations
Authors: King D. P. F. , Hovey S. J. , Thompson D. , Scott A.
Published: April 2005

Mitochondrial DNA (mtDNA) variation was examined in 209 Atlantic salmon from two river systems, the R. Itchen in Hampshire (Southern England) and the R. Conwy (North Wales). Within each system, five spawning sites were sampled. Four enzymes (AVA II, HAE III, HINF I and MBO I) revealed restriction fragment polymorphisms that were informative. Ten clonal lines were observed. These clones were differentially distributed between the two river systems and single clonal types were found to predominate at several spawning sites. MBO I variants were found in salmon from the R. Itchen but not the R. Conwy. A significant heterogeneity in frequency distribution of clonal lines between parr and smolt assemblages of the same year class within the R. Itchen was detected. This heterogeneity suggests that differences in survival or migratory behaviour may be identified by changes in mtDNA clonal frequencies.
Diet, prey selection, and growth of larval and juvenile burbot Lota lota (L.)
Authors: Ghan D. , Sprules W. G.
Published: April 2005

The diet, prey selection, and growth of larval and juvenile Oneida Lake burbot, Lota lota(L.), was investigated from the time of first hatch in mid‐April until their disappearance from the pelagic zone at the beginning of June. Mean length increased exponentially from 3–20 mm on 18 April to 15–00 mm on 29 May. The number and size of prey in burbot stomachs, and the prey size most selected by burbot increased as they grew. Prey width, not prey length, limited the size of prey ingested. The smallest burbot ate and selected highly for the largest prey they could ingest, but older burbot did not. As burbot grew, prey selection was highest first for the rotifer Asplanchna, followed by copepod nauplii, then cyclopoid copepods. Daphnia and calanoid copepods and cyclopoid copepods were selected to similar degrees by 29 May. For a given size, however, cyciopoid copepods were selected more strongly than any other prey type from 18 to 29 May. There were no significant differences in prey selection among offshore, nearshore, and onshore habitats, nor among depths in the offshore habitat.
The spermatic ducts of salmonid fishes (Salmonidae, Teleostei). Morphology, histochemistry and composition of the secretion
Authors: Lahnsteiner F. , Patzner R. A. , Welsmann T.
Published: April 2005

Using light and electron microscopy, enzyme‐histochemistry thin‐layer chromatrography and photometry the functions of the spermatic ducts in salmonid fishes (rainbow trout, Oncorhynchus mykiss, Arctic charr, Salvelinus alpinus; grayling, Thymallus thymallus; whitefish, Coregonus sp.) were investigated. During spawning the spermatic duct of the Salmonidae has a high secretory activity: it synthesizes steroids, lipids (triglycerides, fatty acids, cholesterol esters, phosphatidylcholine), monosaccharides (glucose, fructose), proteins and enzymes (acid and alkaline phosphatase, glucuronidase and proteases). It is important for storage and resorption of spermatozoa. Interspecific differences exist in the storage capacity for semen.
First record of Seriola fasciata (Bloch, 1793) (Osteichthyes: Carangidae) in the Mediterranean
Authors: Massuti E. , Stefanescu C.
Published: April 2005

The capture of a juvenile specimen of Seriola fasciala (Bloch, 1793), a species previously unrecorded in the Mediterranean, is reported from the Badia de Palma (Balearic Islands, North‐western Mediterranean).
Food of 0‐group ocean pout [Macrozoarces americanus (Schneider)] in eastern Newfoundland: the importance of harpacticoid copepods
Authors: Keats D. W. , Steele D. H.
Published: April 2005

Stomachs of 0‐group ocean pout from Newfoundland all contained harpacticoid copepods, which comprised 82% of the diet. 0‐group ocean pout were found hiding among coarsely branched algae.
sGnRH‐A [(d‐Arg6, Pro9, NEt‐)LHRH] in combination with domperidone induces gonad reversal in a protogynous fish, the bluehead wrasse, Thalassoma bifasciatum
Authors: Kramer C. R. , Caddell M. T. , Bubenheimer‐Livolsi L.
Published: April 2005

The effects of thrice weekly injections of Ovaprim (sGnRH‐A in combination with domperidone) on the ovary of Thalassoma bifasciatum, a protogynous marine fish, after 4 and 6 weeks are described. At the end of 4 weeks of treatment, 72% (n=13) of the original females showed signs of reversal. The majority of these were deemed early stage although mid‐ (n=2) and late (n=1) stage reversals were present. At 6 weeks, 92% of the females had ovaries that were undergoing transformation. None of these, however, progressed beyond the early stage. Only 3.8% of the control fish showed signs of reversal over the same periods. The blue head colour pattern, typical of the terminal phase, did not appear in any of the fish.

To our knowledge, this is the first report investigating the hypothalamic influence on sex reversal in T. bifasciatum. These observations shed new light on the neuroendocrine control of reversal of gender in this species and hermaphroditic fishes in general.
Unusual testicular accessory organs, the testicular blind pouches of blennies (Teleostei, Blenniidae). Fine structure, (enzyme‐) histochemistry and possible functions
Authors: Lahnsteiner F. , Nussbaumer B. , Patzner R. A.
Published: April 2005

The testicular blind pouches (TBPs) of Lipophrys canevae and Solaria pavo have an annual reproductive cycle with an active secretion phase during spawning, a regression phase correlated with necrotic processes during post‐spawning, an inactive regeneration phase during inter‐spawning and prespawning. As revealed by fine structure and enzyme‐histochemistry the TBPs of L. canevae and S. pavo are involved in the production of steroid glucuronides, which possibly act as pheromones, Further functions are in the secretion of small amounts of sialomuciri and in lytic activity.
Catabolism of circulating collagen in the Atlantic salmon (Salmo salar)
Authors: Smedsrød B. , Gjøent T. , Sveinbjørnsson B. , Berg T.
Published: April 2005

The catabolic fate of circulating collagen (Col) in the Atlantic salmon (Salmo salar) was studied. Serum t1/2 and organ distribution of circulating Col in salmon were determined using Col conjugated with l25I‐tyramine cellobiose (125I‐TC), a low molecular weight adduct which is trapped intralysosomally at the site of uptake. Intravenously administered l25I‐tyramine cellobioselabelled Col type I was prepared either from salmon skin (sCol) or rat skin (rCol). Biphasic clearance kinetics of l25I‐TC‐sCol in salmon were apparent, with 78% being removed from the circulation in an initial rapid α‐phase (t1/2(α) = 2.4 min), and 22% being removed more slowly in a terminalβ‐phase (t]2(β) = 25.8 min). Serum half life of 125I‐TC‐rCol was found to be 5.4 min (in this type of experiment the number of data points allow the determination of only a monophasic decay slope). Approximately 90% of recovered radioactivity was found in the kidney of the fish. In comparative experiments, 74% of administered 125I‐TC‐sCol was cleared from the circulation of rats during an initial rapid α‐phase with tl/2(α) = 0.8 min, and 26% was eliminated in the terminal β‐phase with t1/2(β) = 7.2 min l25I‐sCol was endocytosed and degraded in pure cultures of ral liver endothelial cells, which are the main site of clearance of circulating Col in the rat. Moreover, Col from the two species competed for the same receptor on cultured rat liver endothelial cells, Intravenous administration of tetramethyl rhodamine isothiocyanate‐labelled sCol (TRITC‐sCol) in salmon, and subsequent examination of sections of kidney in the fluorescence microscope, revealed that the fluorochrome was accumulated exclusively in discrete vesicles of sinusoidal lining cells. Analyses of kidney tissue 24h after intravenous administration of a mixture of fluorescein isothiocyanate‐labelled latex beads and TRITC‐sCol revealed no codistribution of the two fluorochromes, suggesting that the injected Col was taken up in cells different from macrophages. Purified pronephros macrophages prepared after simultaneous injections of stained beads and Col contained only fluorescein‐labelled latex particles. Interestingly, the cells which had accumulated TRITC‐sCol appeared to be equally distributed in both pronephros and the part of the kidney containing tubuli. We conclude that Col which gains access to the circulation of the Atlantic salmon is cleared mainly by uptake into sinusoidal lining cells of the kidney. These cells are distinct from phagocytosing macrophages, and morphologically similar to the highly specialized scavenging endothelial cells of mammalian liver sinusoids.
Thyroid hormone levels in Atlantic salmon (Salmo salar) during the return migration from the ocean to spawn
Authors: Youngson A. F. , Webb J. H.
Published: April 2005

Serum thyroid hormone levels were determined in adult Atlantic salmon (Salmo salar) of both sexes caught in the ocean and at a sequence of locations on their return migration to spawn. Tri‐iodothyronine (T3) levels were greatest in fish caught in coastal or estuarine waters or in a river near head‐of‐tide. T3 levels were lower in fish caught in rivers throughout the angling season and lowest in those captured entering a tributary near spawning. Thyroxine (T4) levels were lowest in immature fish captured in the ocean in winter but raised in fish captured in spring; many of the latter group showed endocrine evidence of their becoming sexually mature. T4 levels were greatest in fish captured in coastal waters and progressively lower in fish captured in an estuary, near head‐of‐tide and in rivers. T4 levels in fish captured at tributary entry near spawning exceeded those in fish caught in rivers earlier in the year. In general, these data support the hypothesis that motor activity level in migrant fish is a determinant of thyroid status.
Novel cell types isolated from the skin of rainbow trout, Oncorhynchus mykiss
Authors: Davidson G. A. , Ellis A. E. , Secombes C. J.
Published: April 2005

Cells were isolated from the skin of rainbow trout, Oncorhynchus mykiss, by collagenase digestion and were observed using light and electron microscopy. Four novel cell types were identified and are described herein.
Ciliated epithelium in the gut of larval Atlantic halibut, Hippoglossus hippoglossus
Authors: Murray H. M. , Wright G. M. , Goff G. P.
Published: April 2005

The presence of cilia was documented in the hindgut of larval Atlantic halibut (Hippoglossus hippoglossus) with the use of electron microscopy. Cilia were shown to be present as late as 8 and 9 day post hatch. These observations were compared to similar observations in more primitive teleosts.
Chronic toxicity of ammonia to juvenile gilthead seabream Sparus aurata and related histopathological effects
Authors: Wajsbrot N. , Gasith A. , Diamant A. , Popper D. M.
Published: April 2005

Effect of 20 days exposure of juvenile gilthead seabream (Sparus aurata) to elevated levels of ammonia on growth and survival was examined in a continuous flow system. Suppressed growth and reduced survival were observed at concentrations of 8.2 and 13 mg l−1 total ammonia‐N (0.5 and 0.7 mg l−1 un‐ionized ammonia‐N, respectively) and higher. The maximum acceptable toxic concentration (MATC) for growth was between 4.8 to 8.2 mg l−1 total ammonia‐N (0.3 and 0.5 mg l−1 un‐ionized ammonia‐N, respectively). Fish exposed to high ammonia levels (13 mg l−1 total ammonia‐N, 0.7 mg l−1 un‐ionized ammonia‐N) displayed clear signs of liver pathology. Existing evidence suggests that S. aurata is less sensitive to ammonia than other reported marine and freshwater fish.

Under certain conditions ammonia concentration in the intensive fish ponds in Eilat may exceed the no observed effect concentration for S. aurata.
The biology of stone loach Barbatula barbatulus in the Rivers Goloustnaya and Olkha, East Siberia
Authors: Skryabin A. G.
Published: April 2005

Five hundred and four stone loach 63–202 mm in total length, of I + to 8 + age groups, were sampled in two rivers of East Siberia from April to October 1989–90. This paper presents data on the seasonal dynamics of fecundity, ripening, fatness and feeding intensity. A second spawning from the end of August to October has been identified for the first time for this species. The absolute fecundity ranged from 1710 to 27600, and the relative fecundity varied from 216 to 833 eggs g−1: (fish weight). Stone loach in the River Olkha grew faster than those in the River Goloustnaya and, according to this index, are closer to stone loach from streams of northern England.
Two‐phase exploration of a novel environment in the guppy, Poecilia reticulata
Authors: Mikheev V. N. , Andreev O. A.
Published: April 2005

Swimming speed and percentage of time fish swam along the boundary of an aquarium gradually decreased with the time following release of juvenile guppies into unfamiliar surroundings. When swimming speed was plotted against time on a log scale, two distinct phases were identified. The high activity phase lasted c, 3 h in 30‐day‐old guppies, 6 h in 10‐day‐olds and not less than S h in 3‐day‐olds. Observed trends in swimming in guppies are interpreted as a component of exploratory behaviour. Alternating the surroundings confirmed the exploratory role of such swimming and suggested that a period of general exploration was followed by a period of more detailed investigation of habitat. An interaction between exploratory and avoidance (fear) responses is discussed.
Factors inducing closure of the micropylar canal in the chum salmon egg
Authors: Kobayashi W. , Yamamoto T. S.
Published: April 2005

The micropylar canal of the chum salmon egg was almost completely closed following egg activation caused by incubation in a hypotonic salt solution (HSS) for I h. The closure occurred in both inseminated and parthenogenetically activated eggs. Incubation of isolated envelopes from non‐activated eggs in HSS or perivitelline fluid (PVF) did not induce any modification in micropylar structure, indicating that normal organization of the egg is essential for inducing closure. To reduce the volume of the perivitelline fluid, the eggs were activated in PVF or HSS containing 8 mM Dextran, Although the envelope showed hardening, closure of the micropyle was not observed in these eggs. The wall of the micropylar canal, however, possessed a slightly rough surface. Following activation in a Ca‐free hypotonic salt solution with 10 mM EDTA, hardening of the egg envelope was completely inhibited. Although such eggs possessed an apparent perivitelline space, neither closure of the micropylar canal nor roughening of the canal surface were detected. We conclude that the synergistic action of perivitelline turgor pressure and perivitelline material is responsible for the closure of the micropyle.
Glochidia of the freshwater mussel,Anodonta anatina, affecting the anadromous European smelt (Osmerus eperlanus) from the Eider estuary, Germany
Authors: Anders K. , Wiese V.
Published: April 2005

During a 2‐year survey on external disease conditions of fish between January 1988 and December 1989, 0.2% of 40011 smelt,Osmerus eperlanus, from 30 stations in the German Wadden Sea and estuaries of tributary rivers, were infected with glochidia of the freshwater mussel Anodonta anatina. Seasonality was marked, with glochidia only being observed in March and April 1989, when prevalences were 37% and 15% respectively, in fish 10–20cm long at the most heavily infected site. A marked increase in prevalence in fish 15cm in length and longer, suggested that only temporarily resident spawning fish (as opposed to resident juveniles) were infected. Infection was almost exclusively restricted to the Eider estuary, where prevalence decreased with increasing salinity. It is concluded that the glochidia carried by smelt returning from their freshwater spawning sites in the Eider River to the sea would have died, thus representing a loss to the 1989 cohort of A. anatina from the Eider. The potential importance of the smelt–A. anatina relationship as indicator for the detection of (a) spawning mussel populations and of (b) possible ecological effects of climate changes is noted.
Migratory behaviour and growth of hatchery‐reared post‐smolt Atlantic salmonSalmo salar
Authors: Jonsson N. , Hansen L. P. , Jonsson B.
Published: April 2005

Individually lagged, 1+ and 2+ hatchery‐reared smolts of Atlantic salmon were released in spring and early summer at the mouth of the R. Imsa, south‐western Norway. The post‐smolts moved mainly northwards in the sea with the coastal current. The estimated mean migratory speed (±s.d.) of those captured in the sea along the Norwegian coast was 7.45 (± 6.26) km day−1; in the fjords it was 1.63 (± 2.33) km day−2. Many of the post‐smohs ascended rivers the same year as released; 37.3% of the total number recaptured were caught in R. Imsa, upstream from the site of release, and 5.8% were caught in other rivers throughout middle and southern parts of Norway. The fish recaptured in rivers was probably sexually mature and entered rivers to spawn. Mean specific growth rate for post‐smolts caught in the sea was higher than for those caught in R. Imsa (P <0.001) but not for those caught in other rivers (P> 0.05). Post‐smolts ascending R. Imsa were smaller at release than those ascending other rivers. However, there was no size difference at release between post‐smolts captured in the sea and those recaptured in rivers other than the R. Imsa.
Reply to the comments of Ryman et al.
Authors: Nyman L.
Published: April 2005

If we want to address ‘genetic concerns’ we should not forget the issue of ‘mental concerns’ in the process. Nyman & Ring (1989) set out to display how a couple of polymorphic loci in Arctic charr (Salvelinus alpinus L.) may and will be used as standard genetic tags for studies on hatchery and wild populations. However, Ryman et al. (1993) address ‘conceptual misunderstandings’ of a general nature. Instead of discussing all the detailed points raised by Ryman et al., I have tried below to address the major issues in Nyman and Ring's original paper.
Fecundity and egg size variation in North American Pacific salmon (Oncorhynchus)
Authors: Beacham T. D. , Murray C. B.
Published: April 2005

We examined regional and latitudinal variation in fecundity and egg weight for five species of Pacific salmon (Oncorhynchus) along the Pacific coast of North America. Data were examined for 24 chum salmon, 15 pink salmon, 34 sockeye salmon, 44 chinook salmon, and 40 coho salmon populations from published sources, unpublished Canadian hatchery records, our own laboratory investigations, and other unpublished sources. Substantial regional variation in fecundity and egg weight was observed, with salmon on the Queen Charlotte Islands and Vancouver Island in British Columbia generally having lower fecundity and larger egg size than nearby mainland populations. The relative distance of freshwater migration to the spawning grounds generally had a marked effect on both fecundity and egg size, with populations spawning in the upper portions in the drainages of large rivers like the Fraser River in British Columbia having reduced fecundity and egg size compared with coastal spawning populations. Fecundity was generally higher and egg size generally lower in more northern populations of sockeye, chinook, and coho salmon compared with southern ones. We suggest that egg size tends to be lower in northern populations of some species as a result of increased fecundity due to their older ages at maturity and a limited amount of energy that can be expended on egg production.
Tidal transport of the bay anchovy, Anchoa mithchilli, in darkness
Authors: Luo J.
Published: April 2005

Transport of the adult bay anchovy, Anchoa mitchilli, in darkness was studied in laboratory and field experiments. In a hydraulic flume, anchovy schooling ceased in darkness and, at a current speed of 30cms−1, 99% of all fish were transported to the end of the flume. In field experiments, fish marked with neutral red dye and released in a creek at flood tide were recaptured 5–1 km upstream 4 h after release at night, and were recaptured within 200m of the release site 3 h after release in daylight. It is concluded that in the neutral environment, bay anchovy schools break up at night and individual fish are transported by currents, whereas in daylight, bay anchovy schools maintain a relatively fixed location. This nocturnal transport phenomena may also exist in other marine and estuarine pelagic fishes, and may help in understanding behaviour and distribution of peiagic estuarine fishes.
Smolt size in relation to age at first maturity of Atlantic salmon (Salmo salar): the role of lacustrine habitat
Authors: O'Connell M. F. , Ash E. G. M.
Published: April 2005

Back‐calculated growth and size of Atlantic salmon smolts were compared in two groups of river systems in Newfoundland. One group consisted of rivers dominated by lacustrine habitats while the other had rivers characterized by fluvial habitats. Back‐calculated length at each age and smolt size was significantly higher for the rivers dominated by lacustrine habitats. Associated with this was a lower proportion of maiden large salmon in adult returns. These findings are discussed in relation to density in fresh water, environmental conditions at sea, and life‐history strategy.
A quantitative study of some digestive enzymes in the rabbitfish, Siganus canaliculatus and the sea bass, Lates calcarifer
Authors: Sabapathy U. , Teo L. H.
Published: April 2005

Digestive enzyme distribution and activity in the digestive tracts of the rabbitfish, Siganus canaliculatus and the sea bass,Lates calcarifer were studied. Quantitative determinations of digestive enzymes in the guts of both fishes showed that they were capable of digesting carbohydrates and proteins in their diet. The carbohydrases, amylase, laminarinase, maltase, sucrase and trehalase were detected in the rabbitfish; their activities being mainly in the stomach, intestine and pyloriccaeca. Amylase, maltase, trehalase and chitinase activities were recorded in the gut of the sea bass, primarily in the intestine and the pyloriccaeca. Their activities were significantly lower than those in the rabbitfish. Proteases (pepsin, chymotrypsin, elastase, leucine aminopeptidase and trypsin) were found in both the rabbitfish and the sea bass. Pepsin activity however, was higher in the sea bass; while trypsin and chymotrypsin activities were higher in the rabbitfish. The activities of the various digestive enzymes in both fishes are discussed in relation to their feeding habits.
The accumulation of dietary aluminium by rainbow trout, Oncorhynchus mykiss, at high exposure concentrations
Authors: Handy R. D.
Published: April 2005

A high oral concentration of 10g Al kg−1 dry weight promoted toxicant accumulation in the muscle, gill, liver, kidney and mucus of trout. One mortality occurred and only a small proportion of the exposure dose was retained by the fish. The limited acute oral toxicity of Al implies that contamination levels found in food species are unlikely to be acutely toxic to wild trout.
Effect of angiotensin II on transepithelial potential in the isolated perfused flounder (Platichthys flesus) gill
Authors: Lyndon A. R.
Published: April 2005

Angiotensin II (Asp1, Val5) perfused through isolated flounder gills inhibited the transepithelial potential by up to 25 per cent at a concentration of 10−9M. There was no effect on gill haemodynamics and the subsequent response to 10−5 M adrenaline was normal.
First occurrence of the North American white sucker Catostomus commersoni in Great Britain
Authors: Copp G. H. , Vaughan C. , Wheeler Alwyne
Published: April 2005

The first specimen of white sucker Catostomus commersoni encountered in Great Britain is reported: a female of 320 mm s.l., 710 g wet body weight, estimated age of 3 +, and ripe with eggs (≃21% of the body weight). Isoelectric focusing of a tissue sampSe was also undertaken.
Predation on Benthosema glaciale (Myctouhidae) by spawning mackerel (Scomber scombrus)
Authors: Walkrr M. Greer , Nichols J. H.
Published: April 2005

During spawning on the outer Dingle Bay Ground mackerel feed on myclnphids which migrate to the surface at night.
The occurrence of juvenile pigmentation abnormalities in plaice (Pleuronectes platessa) larvae fed on enriched and unenriched Artemia salina nauplii
Authors: Dickey‐Collas M.
Published: April 2005

The effect of diet on the frequency of malpigmentation was investigated in laboratory‐reared plaice (Pleuronectes platessa) fed on either enriched or unenriched Artemia salina nauplii. The juveniles fed continuously on unenriched Artemia during their larval period showed 29.0% normal pigmentation whereas those fed solely on enriched Artemia, showed 63% normal pigmentation. The possibility of a critical period for pigment development was tested by changing the diet of larvae at different ages. Results suggested that a critical period is less important than the duration of time fed on a nutritionally complete diet.
Low level infection by eye fluke, Diplostomum spp., affects the vision of three‐spined sticklebacks, Gasterosteus aculeatus
Authors: Owen S. F. , Barber I. , Hart P. J. B.
Published: April 2005

Experiments have shown thai infection by low intensities of the eye fluke affects the vision of three‐spined stickleback when selecting prey, and also shortens the reactive distance to the prey. The results have consequences for the fitness of the individual, and also for the study of prey selection.
Substantial northward range extension for Gephyroberyx darwini (Berycoidei, Trachichthyidae) in the western North Atlantic, possibly explained by habitat preference
Authors: Van Guelpen L.
Published: April 2005

Gephyroberyx darwini, herein reported northward to Browns Bank in the western North Atlantic, may inhabit rarely sampled hard substrata in northern temperate and boreal slope waters.
Aspects of reproduction and diet of the long‐finned herring, Ilisha africana, off Cape Coast, Ghana
Authors: Yankson K. , Azumah E. G. S.
Published: April 2005

I. Africana off Cape Coast bred continuously throughout the year. The major breeding season was preceded by a period of high feeding activity, mainly on fish fry, penaeid shrimps and crustacean zooplankton.
Reproduction of the inshore coral trout Plectropomus maculates (Perciformes: Serranidae) from the Central Great Barrier Reef, Australia
Authors: Ferreira B. P.
Published: April 2005

The reproductive biology of the serranid fish Plectropomus maculatus sampled from inshore waters of the Central Great Barrier Reef was studied based on histological analyses of gonad material. This species was shown to be a monandric protogynous hermaphrodite. The process of sex change foliowed the spawning period observed during September through November. Plectropomus: maculatus showed multiple spawning during this period. Sex change followed the usual protogynous mode with degeneration of ovarian germinal tissue accompanied by proliferation of male germinal tissue in the gonad. The sex structure of the sampled population was analysed based on age and size information. The size and age of first reproduction for females was 30.0cm s. L. and 2 years of age. The size and age of sex‐transition was 35.4 cm s. L. and 4.4 years of age. The sex/size and sex/age relationships indicated that sex‐change can occur over a broad range of sizes and ages. The sizes and age distributions of males and females P. maculates overlapped over 38% of the length range and over 42% of the maximum age observed.
The effects of temperature acclimation on organ/tissue mass and cytochrome c oxidase activity in juvenile cod (Gadus morhua)
Authors: Foster A. R. , Hall S. J. , Houlihan D. F.
Published: April 2005

Cod were acclimated to 5 and 15° C (cold and warm acclimation, respectively) for at least 43 days after which tissue‐somatic indices, tissue protein, DNA content, and cytochrome c oxidase (CCO) activity were measured. Liver, stomach, intestine, total heart and ventricle‐somatic indices were all increased significantly in the cold acclimated animals compared with their warm acclimated counterparts. There were no differences in gill or white muscle‐somatic indices between the acclimation temperatures. Tissue protein concentration (mg protein g tissue−1) was generally unaffected by temperature acclimation. Cold acclimation resulted in higher white muscle and lower ventricle CCO specific activities(μmol cytochrome c oxidized min−1· g tissue−1) compared with the respective warm acclimated tissues. No significant differences in CCO specific activity were observed in the remaining tissues (when measured at an intermediate temperature of 10° C). Total tissue CCO activity (measured at an intermediate temperature of 10° C) did not differ significantly between the cold and warm acclimated fish.
Ventilation of the gills by the pectoral fins in the fangtooth Anoplogaster cornutum: how to breathe with a full mouth
Authors: Davenport J.
Published: April 2005

The midwater fangtooth Anoplogaster cornutum eats large prey items whole. To eat prey the fish distends the opercula and spreads the gill arches apart. The pectoral fins are then used to fan water over the gills until ingestion is completed.
The fisheries biology of flying fishes (Families: Exocoetidae and Hemiramphidae) from the Camotes Sea, Central Philippines
Authors: Dalzell P.
Published: April 2005

The catches of a small artisanal fishery for flying fishes (Families Exocoetidae and Hemiramphidae) on the Danajon Bank in the Camotes Sea. Central Visayas, were recorded during a 14‐month period between 1987–1988. Catches were made using floating drive‐in‐nets deployed from small motorized canoes. Three species, Cheilopogon nigricans, Cypselurus opisthopus and Oxyporhamphus convexus, formed about 90% of landings. Growth, mortality and related parameters for the three dominant species in the catch were estimated from length‐frequency data. Seasonal variations in catch rate and recruitment are described and thought to be linked to the two monsoon periods in the Philippines. Total mortality rates were very high and, while these may be the result of migratory movements rather than attrition, they are a cause for concern in such a highly selective fishery.
Age and growth of three species of clupeids from Kiribati, tropical central south Pacific
Authors: Milton D. A. , Blaber S. J. M. , Rawlinson N. J. F.
Published: April 2005

The age and growth of three widely distributed tropical clupeids, Amblygaster sirm, Herklotsichthys quadrimaculatus and Spratelloides delicatulus at four sites in Kiribati were examined by otolith increment counts. Amblygaster sirm grew to 230 mm s.l. and 130 g and lived for up to 2 years at all sites. Herklotsichthys quadrimaculatus grew to 110 mm and 15 g and lived up to 1 year; white S. delicatulus grew to 66 mm and 2.5 g and lived for 4‐5 months. There was little difference in the rate of growth in length of any of the species at the sites, except for S. delicatulus at one site. All species grew rapidly in length at the expense of growth in weight during the early life‐stages when mortality is highest, hence reducing the time they spend in this life‐stage. The relationship between weight and age varied between the sites for H. quadrimaculatus and S. delicatulus, but these differences narrowed as fish size increased. Herklotsichthys quadrimaculatus also grew more rapidly in weight during the first 3 months than the other species. Growth comparisons between the three species showed that all grew in length at similar rates for the first 2 months. Spratelloides delicatulus became sexually mature at 2 months of age and subsequently grew more slowly than the other species. After 4 months A. sirm grew faster than H. quadrimaculatus. The rates of growth in length and weight of these species from Kiribati were compared with those from other regions of the Indo‐Pacific. There were significant differences: A. sirm grew to a larger size in Kiribati than elsewhere; H. quadrimaculatus grew at a similar rate at all sites during the first 2 months, but then the growth rate of Kiribati fish declined and they reached a smaller asymptotic size than elsewhere; S. delicatulus from Kiribati grew in length at similar rates to Solomon Islands fish, but were significantly lighter in weight at the same age. The relative growth performance of these short‐lived tropical species was compared to that of temperate clupeids. All species showed similar growth performance despite the slower growth rates of temperate species, which suggests that the clupeoids' phylogenetic conservatism in some life history traits extends to growth. Regional and local differences in growth rates of some tropical clupeids are as large as those found among most clupeid species.
Evidence of predatory control of yellow perch (Perca flavescens) recruitment in Lake Erie, U.S.A.
Authors: Hartman K. J. , Margraf F. J.
Published: April 2005

Predation can be a major factor in recruitment success of yellow perch (Perca flavescens Mitchitl). Trawl catches of age‐0 yellow perch in western Lake Erie declined from 870·3 per trawling h in June to 3·3 per trawling h in late July 1988. Coincident with the decline in relative abundance of age‐0 yellow perch we found large numbers of age‐0 yellow perch in the stomachs of small walleyes (Stizostedion vitreum Mitchill). From this evidence we hypothesized that predation by walleyes may have caused the demise of the 1988 year‐class of yellow perch. We used a population and bioenergetics modelling approach to estimate the impact of walleye predation on the abundance of age‐0 yellow perch. Modelling showed that 6·8 × 109 age‐0 yellow perch that had attained 18 mm total length (t.l.), were eaten by small (age‐2 and younger) walleye from June through July 1988. We estimated that walleye ate 28·4–89·7% of the yellow perch reaching 18 mm t.l. during 1988. The majority of this predation (77% of total) was by the abundant age‐2 cohort of walleyes. We concluded that, even in a large system such as Lake Erie, predation can play a major role in structuring year‐class strength of yellow perch and, thus, management of percid fisheries should be conducted on a fish‐community basis.
The seasonal changes in somatic energy content of Gulf of Alaska yellowfin sole, Pleuronectes asper
Authors: Paul A. J. , Paul J. M. , Smith R. L.
Published: April 2005

Seasonal measurement of body energy content was made for Pleuronectes asper (Pallas, 1814) from the Gulf of Alaska. Whole body energy content of complete fish (∼ 3472 J g−1 wet wt) was minimal in May for females as their overwintering phase ended, then increased to ∼ 4456 J g−1 prior to spawning. The ovarian index [(g.w./t.w.) × 100] and energy content of ovaries (J g−1) was highest in June and May respectively, and then declined markedly by August as spawning occurred.

Throughout the year male whole body energy content of complete fish ranged from 3351 to 4590 J g−1 with the lowest values in May and highest values occurring during June to September, the feeding season. The testes index [(g.w./t.w.) × 100] and total energy content of testes (J g−1) were high in March and lowest during June and July. On a weight‐specific basis, males and females had similar whole body energy values throughout the year.

Juveniles followed the same seasonal trends in energy storage as adults and had similar whole body energy values. Whole body energy content was linearly related to wet and dry weight condition factor with r2 values of 0.70 and 0.87, respectively. Dry body weight as percent of wet body weight was the best predictor of body energy (r2=0.91).

Yellowfin sole had an annual energy cycle with energy accumulation and growth from May to September. Thereafter they utilized stored energy for metabolic and reproductive needs. Spawning began in late May or early June and fish were spent by August. Whole body energy content increased by 28, 33 and 35% between May and June, for females, juveniles, and males, respectively, the most dramatic change during the year long survey. This suggests that intense feeding in May must be an important aspect of their energy storage cycle.
Sexual cycle and seasonal changes in the ovary of the red mullet, Mullus surmuletus, from the southern coast of Brittany
Authors: N'Da K. , Déniel C.
Published: April 2005

The reproductive cycle of the red mullet is described on a macroscopic scale in terms of the GSI, HSI and K, and on a microscopic scale in terms of histological changes in the ovary and changes in the oocyte size frequency distribution. On the southern coast of Brittany the red mullet breeds in May and June. During oogenesis, the previtellogenic period lasts 6 months and the secondary phase of vitellogenesis no more than 3 months. When spawning commences the process of vitellogenesis ceases and up to 20% of the vitellogenic oocytes become atretic. Prior to spawning a single batch of oocytes can be seen to be entering secondary vitellogenesis. During the immediate prespawning and spawning periods the existing vitellogenic oocytes mature but there is no recruitment from the stock of previteilogenic oocytes. This results in a gap or hiatus in the oocyte size frequency distribution between previtellogenic and vitellogenic oocytes within which there are very few resting or maturing oocytes. The red mullet appears to be a determinate spawner, in which egg loss through atresia considerably reduces the potential fecundity.
Introductions, spread and colonization of new localities by fish helminth and crustacean parasites in the British Isles: a perspective and appraisal
Authors: Kennedy C. R.
Published: April 2005

Most parasites are disseminated by movements of infected hosts. The increasing extent and rapidity of anthropochore fish movements are causing increased concern related to awareness of their potential and known capacity for disseminating parasites. This paper puts these data in perspective by examining examples of actual and potential translocations of fish helminthes and crustaceans by anthropochore movements offish into and throughout the British Isles, and by distinguishing the processes of dissemination and invasiveness from those of colonization and establishment. An investigation of the British fish and helminth parasite fauna suggests that: (1) the range of many species is not well known, many are local in distribution and appearances beyond the range may reflect detection and patchiness, not translocation; (2) taxonomic problems in many groups hinder detection and determination of range; (3) most parasites possess the attributes of good colonizers so the natural expansion and contraction of ranges are often not noticed or recognized as such and the importance of parasite introductions by natural movements of fish or avian hosts is generally underestimated; (4) invasions are far commoner than colonizations, since conditions for establishment may be very restricted and transmission windows very narrow in time and space; (5) successful colonizations and translocations tend to be documented and attract attention whereas invasions resulting in failed colonizations are seldom observed and more seldom documented, thus biasing our perception. Given the extensive history of fish introductions to, and translocations within, the British Isles it is surprising how few fish helminths and crustaceans have invaded the country successfully (16 species: 11·4%) and how many still show restricted distributions. The majority (68·7%) of introduced helminths are associated with fish having ornamental varieties. Barriers of colonization are more effective than those to invasion and it is clear that most translocations and invasions fail. It is right to be concerned about the dangers, but it is also important to put anthropochore factors in perspective.
The occurrence of the lesser weever in the Azores
Authors: Nash R. D. M. , Santos R. S.
Published: April 2005

The occurrence, abundance and day/night differences in catch with a beach seine are reported for a population of lesser weever at Porto Pim Bay, Faial, Azores from June 1989 to June 1990. The highest catches in shallow water occurred in September, and were greater at night.
Exceptionally rapid growth and early maturation of perch in a freshwater lake recently converted from an estuary
Authors: Houthuijzen R. P. , Backx J. J. G. M. , Buuse A. D.
Published: April 2005

In the recently freshened Volkerak, in the SW Netherlands, age 0‐2 perch attained mean lengths of 12, 24 and 30 cm fork length. Males matured at age 0 and females at age 1. This exceptionally rapid growth and early maturation was due to abundant availability of zooplankton andNeomysis integer, at low fish biomass during change from a marine towards a freshwater fish community.
Effects of size and early sexual maturity on downstream migration during smolting in Baltic samon (Salmo salar)
Authors: Fängstam H. , Berglund I. , Sjöberg M. , Lundqvist H.
Published: April 2005

The effects of size and previous sexual maturity on downstream migration in two‐summer‐old Baltic salmon were studied during their normal seaward migratory period in spring. We used an automatic PIT (Passive Integrated Transponder) tag monitoring system for individual recognition of tagged fish. Size affected the probability of migration among both previously immature and previously mature males while there was no such relationship among females. Nearly all females and 63.6% of the previously immature males migrated during the smolting period, while only 24.5% of the previously mature males did. In migrating fish the individual activity level increased from almost zero in May to about 450 antenna passages per day in mid June, coinciding with a pronounced increase in ambient water temperature. During the period of increasing activity in early June the fish changed from night activity to day activity and finally activity all day and night. The fish moved downstream in schools but no specific school size dominated. This paper demonstrates the strong effect of body size and previous sexual maturity on the probability of migration.
Initiation of gynogenesis in Oreochromis niloticus following heterologous fertilization
Authors: Peruzzi S. , Scott A. G. , Domaniewski J. C. J. , Warner G. F.
Published: April 2005

Fertilization of tilapia (Oreochromis niloticus) eggs with heterologous sperm from carp (Cyprinus carpio), and from some other eyprinids resulted in higher levels of haploid gynogenetic development than in unfertilized eggs. Normal and irradiated carp sperm achieved similar rates of activation of tilapia eggs, but lower rates than those achieved by irradiated tilapia sperm. Diploidy in gynogenetic eggs fertilized with carp sperm was restored using pressure shocks and resulted in the development of healthy tilapia gynogens.