Deep water observations of Lophius piscatorius in the north‐eastern Atlantic Ocean by means of a remotely operated vehicle

To determine whether the current classification of the flathead trout Salmo (Platysalmo) platycephalus , endemic to the upper reaches of the Zamanti River system, Turkey, based solely on morphology, is in congruence with molecular phylogeny, the nucleotide sequence variation in mitochondrial (control region and cytochrome b gene) and nuclear (internal transcribed spacer of rRNA genes) DNA for the flathead trout and various representatives of the genus Salmo was studied. On the basis of pair‐wise genetic distance estimates, the highest differences were found to exist between the flathead trout and S. salar , S. ohridana and S. obtusirostris , whereas the differences between the flathead trout and S. trutta were minimal. All the analyses performed firmly positioned the flathead trout within the Adriatic phylogeographic lineage of S. trutta ; however, the exact position of the flathead trout within the Adriatic cluster was irresolvable. Accordingly, classifying the flathead trout as a subgenus of Salmo is unjustifiable and its reclassification in a lower taxonomic category is suggested by the present study.     

Minisatellite DNA fingerprints of salmonid fishes

The human minisatellite probes 33.6 and 33.15 cross-hybridized to DNA digests of Atlantic salmon, brown trout and rainbow trout revealing complex multi-banded patterns. These DNA fingerprints (in excess of 40 resolvable fragments in some cases) were highly polymorphic, individual specific and found to be stable, both somatically and in the germline. Pedigree analysis of an Atlantic salmon family confirmed that the minisatellite fragments showed Mendelian inheritance. With only a single occurrence of linkage and allelism being observed it is likely the minisatellite loci are widely distributed throughout the salmonid genome. The potential applications for both multi- and single locus minisatellite probes in salmonid research are discussed.     

Continuous outmigration and sequential encountering of environmental cues are important for successful homing of hatchery-reared,anadromous brown trout Salmo trutta

When rehabilitating and reintroducing trout Salmo trutta in rivers, it is a goal that as many as possible survive, home and form self-sustaining populations. Hatchery-reared, anadromous S. trutta have significant lower ability to return to the area where they were raised if (a) transported in a closed tank to sea and released 5 km from the River Imsa, relative to those that were (b) transported when swimming in a partly submerged tank with sea water run-through, while being slowly towed by a boat the same distance or (c) released at the outlet of the River Imsa. Thus, if deprived from environmental cues during part of the way, they lose their ability to home.     

Variation in mitochondrial DNA and post-glacial colonization of north western Europe by brown trout

A purified mitochondrial DNA (mtDNA) probe was used to examine restriction fragment length polymorphisms produced by six restriction enzymes ( Xba I, Eco RV, Ava II, Hinf I, Hae III, Mbo I) in 915 brown trout from western Europe. A total of 20 composite haplotypes were found with one to seven haplotypes in individual populations. Icelandic trout samples from north, south, east, and west coast drainages showed only a single common haplotype in contrast to the high level of polymorphism found in Irish and Scottish populations. The phylogeny of mtDNA haplotypes and the pattern of haplotype distribution suggests that post-glacial colonization of brown trout in NW Europe was more complex than the dual colonization model which has been proposed on the basis of differential LDH-5* allele distribution. For example, Lough Melvin (Ireland) appears to have been independently     

Evidence for phylogeographically informative sequence variation in the mitochondrial control region of Atlantic brown trout

Complete sequencing of the mitochondrial control region was undertaken among brown trout Salmo trutta from North Atlantic areas where previous studies, based on smaller mtDNA fragments, failed to detect any phylogeographic signal. Comparison of sequences suggests that brown trout in the Iberian Peninsula and Scandinavia belong to largely divergent evolutionary units.     

Assessment of digestive enzymes activity during the fry development of the endangered Caspian brown trout Salmo caspius

The study of digestive enzymes activity at Salmo caspius fry showed that enzymes were available at the moment of mouth opening on the first day post hatching (dph) and the activity of enzymes showed no significant difference from the hatching day 28 dph. An increased activity was seen between 32 and 43 dph and this activity was significantly higher than the activity during the first 28 days. In the primary stages after yolk sac resorption (43–58 dph), enzymes activity showed an increased profile, however none of them showed a significant difference between 43 and 58 dph.     

Temporal variations of genetic introgression in stocked brown trout populations

Allozymes were used to analyse the genetic impact of hatchery brown trout Salmo trutt a, morpha fario stocked in wild Mediterranean populations to gain a better understanding of the mechanisms of introgression (regulation, elimination or homogenization). Analysis of the genetic structure of populations from the same river drainage basin but subjected to different incidences was performed in space and time (data on two generations and 2 years of sampling). Introgression is associated with high deficits of heterozygotes and linkage disequilibria. Genetic divergence according to age group was observed. These results may indicate selective forces acting against domesticated genes and limiting hybridization between the two forms.     

Spawning characteristics of the anadromous brown trout in a small Swedish stream

The spawning pattern of the anadromous brown trout Salmo trutta was studied in Själsöån, a small stream in Gotland, Sweden, during eight winters between 1992–1993 and 1999–2000. The total length ( L _T) at spawning was normally distributed (185–890 mm) for females and multimodal for males (300, 400 and 550 mm most frequent length classes). Spawning males were significantly younger (2+ to 4+ years) than females (3+ to 5+ years). The sex‐ratio at the beginning and at the end of the spawning season favoured males. The mean ±  s . d . number of spawners was 70 ± 16 individuals per year. Migration into and out of the stream occurred between November and June. The highest number of spawning fish was found in the stream at the end of November or at the beginning of December. Migration mainly occurred during high water flow and at night. The majority of the females entered the stream and spawned the same (29·3% of all the females) or the next night (32·8% of all the females) while males may have stayed for 2 to 3 weeks (21·3% of all the males) in the stream before spawning. Males usually remained much longer in the stream (mean ±  s . d . 45 ± 56 days) than females (16 ± 30 days). Females lost more mass in the stream (mean ±  s . d . 17·3 ± 8·6%) than males (7·7 ± 9·6%). For both sexes, mass loss was positively correlated with the time spent in the stream. Only 7·3% of the males and 5·7% of the females occurred in the stream for >1 year. Spawning took place only during the night.     

Distribution, growth and movement of River Usk brown trout (Salmo trutta)

The River Usk catchment in South Wales supports mainly freshwater resident brown trout, with few anadromous fish. Electric fishing and netting revealed that age-class distribution differed between main river and tributary habitats, the latter environment acting as a nursery area for young fish. Few fry were found at main river sites. Age-class distribution also differed between tributary systems, and possible reasons are discussed. Trapping experiments indicated that trout move to main river habitat at 2+ yr. Lengths at age (back-calculated from scale reading) were similar for main river and tributary resident fish at 1 and 2 year, but main river fish were larger at 3 and 4 yr. This habitat shift and size difference is discussed with reference to current angling regulations.     

An outline of a revised classification of Saxifraga L.

GORNALL, R. J., 1987. An outline of a revised classification of Saxifraga. A revised classification of Saxifraga is presented in which 15 sections, 19 subsections and 34 series are recognized. A total of 394 names are accounted for, including the following new taxa, combinations and names: series Hirculoideae (Engler & Irmscher) Gornall, stat. nov.; series Lychnitidae (Engler & Irmscher) Gornall, stat. nov.; series Nulanles (Engler & Irmscher) Gornall, stat. nov.; series Cinctae (H. Sm.) Gornall, stat. nov.; series Gemmiparae (Engler & Irmscher) Gornall, stat. nov.; series Spinulosae (C. B. Clarke) Gornall, stat. nov.; subsection Rosulares Gornall, nom. nov.; subsection Serpyllifoliae Gornall, subscct. nov.; subsection Hemisphaericae (Engler & Irmscher) Gornall, stat. nov.; section Merkianae (Engler & Irmscher) Gornall, stat. nov.; subsection Stellares (Engler & Irmscher) Gornall, stat. nov.; series Birostres Gornall, ser. nov.; series Melanocentrae (Engler & Irmscher) Gornall, stat. nov.; series Astasianlhes (Sternberg) Gornall, stat. nov.; subsection Micranthes (Haworth) Gornall, stat. nov.; series Aulaxis (Haworth) Gornall, stat. nov.; series Dermasea (Haworth) Gornall, stat. nov.; series Micranthes (Haworth) Gornall, stat. nov.; scries Aretioideae (Engler & Irmscher) Gornall, stat. nov.; series Juniperifoliae (Engler & Irmscher) Gornall, stat. nov.; series Lilacinae Gornall, ser. nov.; series Marginatae (Engler & Irmscher) Gornall, stat. nov.; series Squarrosae (Engler & Irmscher) Gornall, stat. nov.; series Rigidae (Engler & Irmscher) Gornall, stat. nov.; subsection Engleria (Siindermann) Gornall, stat. nov; series Subsessiliflorae Gornall, ser. nov.; series Oppositiofoliae (Hayek) Gornall, stat. nov.; series Tetrameridium (Engler) Gornall, stat. nov.; subsection Mutatae (Engler & Irmscher) Gornall, stat. nov.; subsection Florulentae (Engler & Irmscher) Gornall, stat. nov.; section Odontophyllae Gornall, sect, nov.; series Biternatae (Engler & Irmscher) Gornall, stat. nov.; subsection Triplinervium (Gaudin) Gornall, stat. nov.; series Arachnoideae (Engler & Irmscher) Gornall, stat. nov.; subsection Tridactylites (Haworth) Gornall, stat. nov.     

Allozyme diversity in brown trout (Salmo trutta) from Central Spain: Genetic consequences of restocking

1.  The brown trout ( Salmo trutta ) represents one of the main freshwater resources in Spain, but habitat alterations and overharvesting have contributed to the decline or disappearance of numerous natural populations. In addition, reinforcement programs of wild populations based on releases of hatchery reared fish of exogenous origin compromise the conservation of remnant native trout resources.
2.  We present allozymic data from Central Spain trout populations including stocked and unstocked populations. Although the levels of genetic variation observed were low and affected by hatchery releases (p = 18.23%, Ho= 3.39%), they were within the range observed in other European areas.
3.  The effective introduction of hatchery reared fish is genetically homogenising the populations in the studied area and disturbing the ancestral pattern of genetic variation that distinguishes the Tajo and Duero basins. Within the eight natural populations analysed, seven had alleles assigned to the foreign trout. The introgression in these populations, following the LDH-5 * 90 allele frequency, ranged between 2% and 29.4%, but those values are not in concordance with the respective stocking effort undertaken in each population. Moreover, the release of hatchery-reared fish does not solve the problems related to the reduced size of wild populations and their recruitment instability.     

Effects of sea trout stocking on the population genetics of landlocked brown trout, Salmo trutta L., in the Conwy River system, North Wales, U.K.

The effect of the introduction of fry of anadromous sea trout, Salmo trutta L., on the genetic integrity of landlocked brown trout populations was evaluated. Samples were taken from six brown trout populations from streams above impassable waterfalls in the Conwy river system (North Wales, U.K.) in 1989 and 1990. Three of these streams had no known stocking history and three had been stocked with sea trout fry from the lower Conwy system over the last few years. Representatives of these sea trout were collected from two streams in the lower Conwy system and from a hatchery. Allele frequencies at 13 loci, six of which were polymorphic, were determined by starch gel electrophoresis.
The stocked populations were intermediate in their allele frequencies between unstocked brown trout and sea trout samples. A principal component analysis suggested significant numbers of hybrids in all of the stocked streams. This shows that some of the introduced sea trout did not migrate down the falls to the sea, but stayed in fresh water and hybridized with the local population. The significance of this finding for the conservation of the genetic resource of brown trout stocks is discussed.     

The importance of being familiar: individual recognition and social behavior in sea trout (Salmo trutta)

This study addressed two hypotheses: (1) that individual recognitionis used to reduce the cost of contesting resources in sea troutand (2) that the hatchery environment selects against individualrecognition. Predictions from these hypotheses were tested inlaboratory experiments where behavior and growth were studiedin juvenile sea trout. In tact groups of familiar fish werecompared with groups that contained both familiar and unfamiliarindividuals. In general, the results were in agreement withthe first hypothesis. Familiar fish in intact groups had morestable dominance ranks, higher food intake, and better utilizationof food. Familiarity also reduced the distance to the nearestneighbor. Furthermore, initiators of conflicts were more likelyto win against familiar fish than against strangers. These resultssupport game-theory-based hypotheses explaining the dear-enemyphenomenon as an effect of familiarity A picture emerges inwhich familiarity stabilizes the hierarchical structure of agroup and governs behavioral modifications that will promotefeeding and growth, in turn leading to higher fitness. The secondhypothesis, which predicted a reduced effect of individual recognitionin sea-ranched trout, was not strongly supported because familiarityaffected sea-ranched and wild trout similarly in most respects.However, familiarity was not beneficial for growth in sea-ranchedtrout, whereas it increased growth rate in wild fish. In addition,sea-ranched trout tended to maintain larger distances to theirnearest neighbors than did wild trout.     

Retention of visible implant and visible implant elastomer tags in brown trout in an English chalk stream

Retention of both rigid and new soft standard size visible implant (VI) tags in brown trout Salmo trutta after 6 months varied between 42 and 97% for different batches, with no evidence of increased retention of the new type of tag. The 6 month retention of visible implant elastomer tags (VIE) also varied but with a mean of 96%. The VIE retention gradually declined with time up to 42 months.     

Plasma steroid concentrations in relation to the reproductive cycle of cultured male Rhamdia quelen

Seepage water through a lake bottom and the layering of tight and high-permeable layers in the aquifer produce groundwater under greater pressure than the water column of the lake. This results in under-water springs and seepages. When spawning substrata were available, there was a spatial correlation between the degree of groundwater influx and the redd density of brown trout Salmo trutta . In high density spawning areas with > 100 observed redds ha⁻¹, the mean seepage water influx during spring was c . 1200 ml m⁻² min⁻¹ compared to a mean flux of 113 ml m⁻² min⁻¹ in low density spawning areas with 5–10 redds ha⁻¹.     

Rare and fleeting: an example of interspecific recombination in animal mitochondrial DNA

Recombination is thought to occur only rarely in animal mitochondrial DNA (mtDNA). However, detection of mtDNA recombination requires that cells become heteroplasmic through mutation, intramolecular recombination or 'leakage' of paternal mtDNA. Interspecific hybridization increases the probability of detecting mtDNA recombinants due to higher levels of sequence divergence and potentially higher levels of paternal leakage. During a study of historical variation in Atlantic salmon (Salmo salar) mtDNA, an individual with a recombinant haplotype containing sequence from both Atlantic salmon and brown trout (Salmo trutta) was detected. The individual was not an F1 hybrid but it did have an unusual nuclear genotype which suggested that it was a later-generation backcross. No other similar recombinant haplotype was found from the same population or three neighbouring Atlantic salmon populations in 717 individuals collected during 1948-2002. Interspecific recombination may increase mtDNA variability within species and can have implications for phylogenetic studies.     

Mitochondrial DNA hypervariable region-1 sequence variation and phylogeny of the concolor gibbons, Nomascus

The still little known concolor gibbons are represented by 14 taxa (five species, nine subspecies) distributed parapatrically in China, Myanmar, Vietnam, Laos and Cambodia. To set the stage for a phylogeographic study of the genus we examined DNA sequences from the highly variable mitochondrial hypervariable region-1 (HVR-1 or control region) in 51 animals, mostly of unknown geographic provenance. We developed gibbon-specific primers to amplify mtDNA noninvasively and obtained >477 bp sequences from 38 gibbons in North American and European zoos and >159 bp sequences from ten Chinese museum skins. In hindsight, we believe these animals represent eight of the nine nominal subspecies and four of the five nominal species. Bayesian, maximum likelihood and maximum parsimony haplotype network analyses gave concordant results and show Nomascus to be monophyletic. Significant intraspecific variation within N. leucogenys (17 haplotypes) is comparable with that reported earlier in Hylobates lar and less than half the known interspecific pairwise distances in gibbons. Sequence data support the recognition of five species (concolor, leucogenys, nasutus, gabriellae and probably hainanus) and suggest that nasutus is the oldest and leucogenys, the youngest taxon. In contrast, the subspecies N. c. furvogaster, N. c. jingdongensis, and N. leucogenys siki, are not recognizable at this otherwise informative genetic locus. These results show that HVR-1 sequence is variable enough to define evolutionarily significant units in Nomascus and, if coupled with multilocus microsatellite or SNP genotyping, more than adequate to characterize their phylogeographic history. There is an urgent need to obtain DNA from gibbons of known geographic provenance before they are extirpated to facilitate the conservation genetic management of the surviving animals.     

The Diet of the Brown Trout Salmo trutta (L.) during the Reproductive Period: Size‐Related and Sexual Effects

We investigated the autumnal diet of the brown trout Salmo trutta, in a Prepyrenean stream (NW Iberian Peninsula) focusing on intraspecific dietary differences related to size and sex. The diet of trout included 18 types of prey, with Plecoptera and Ephemeroptera nymphs and Diptera larvae as the most consumed taxa. Large trout ate larger prey, than did small trout, and also increased the consumption of terrestrial‐surface prey with respect to aquatic‐benthic prey. As terrestrial‐surface preys were larger than aquatic‐benthic prey, the size‐related differences in the diet of trout were related to gape‐limitations. Although male and female trout did not differ in size, we found that males foraged on a more diverse type of prey than females, probably owing to male territoriality during the reproductive period. This study provides new evidence of dietary plasticity in the brown trout and confirms the importance of local dietary studies to better understand factors which drive trophic ecology of predators. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

An intensive study of allozyme variation in freshwater resident and anadromous trout,Salmo trutta L., in western Ireland*

Ten polymorphic enzyme coding loci were assayed using starch gel electrophoresis in anadromous (sea trout) and freshwater-resident trout, Salmo trutta, from two neighbouring river systems draining into Clew Bay in western Ireland. Samples were collected from the Burrishoole and from the neighbouring Newport river system. In the Burrishoole system, two samples were from above waterfalls impassable to migratory trout, two consisted of anadromous smolts or post-smolts and the remainder were freshwater-resident trout from freely accessible areas. There were large differences in gene frequency between trout from above impassable barriers and all others sampled, and these two groups also differed substantially from each other. More minor differences were evident between some other samples, particularly between trout from the upper lake and streams entering it and a stream associated with the lower lake. Two anadromous populations therefore occur in the Burrishoole system. In contrast, no differences were evident in two sampling years between anadromous trout and cohabiting freshwater-resident trout from the upper part of the Burrishoole system. Thus, in the upper part of this system, anadromous trout do not appear to comprise a separate population from non-migratory trout and interbreeding may occur.