736 research outputs found
Old Eagle Mill on South Main Street shortly after purchase from E.N. Fish
No full textOld Eagle Mill on South Main Street shortly after purchase from E.N. Fish (1898). Eagle Milling was established in 1865 and the facilities were completed in 1870.
Trends in Wadden Sea Fish Fauna, Part II: Dutch Demersal Fish Survey (DFS)
No full textShallow waters along the North Sea coast provide nursery areas for juveniles of several fish species, including commercially exploited species, and natural habitat for resident species and seasonal visitors. These areas have gone through major changes in the last decades due to climate change and human activities, which will likely result in changes in the abundance and species composition of the fish fauna in coastal waters
Embryonic temperature and the genes regulating myogenesis in teleosts
No full textIn this study, full coding sequences of Atlantic salmon (Salmo salar L.) muscle genes were cloned, including myogenic regulatory factors (MRFs) (myod1c, myog, mrf4, myf5), inhibitors of Myostatin (fst, decorin), markers of myogenic progenitor cell (MPC) proliferation (sox8) and fusion (calpastatin), a marker of slow muscle fibre differentiation (smlc1) and a novel eukaryotic gene involved in regulating growth (cee). Several of these genes were then characterised using a range of experimental and computational analyses with the aim to better understand their role in myogenesis and their evolution in teleosts.
A series of experiments supported previous findings that teleosts have extra copies of many genes relative to tetrapods as a result of a whole genome duplication (WGD) event that occurred some 320-350 Mya. For example, it was shown that genes for myod and fst have duplicated in a common teleost ancestor, but were then specifically lost or retained in different lineages. Furthermore, several characterised Atlantic salmon genes were conserved as paralogues, likely from a later WGD event specific to the salmonid lineage. Phylogenetic reconstruction and comparative genomic approaches were used to characterise the evolution of teleost paralogues within a framework of vertebrate evolution. As a consequence of one experiment, a revised nomenclature for myod genes was proposed that is relevant to all diploid and polyploid vertebrates.
The expression patterns of multiple myogenic genes were also established in Atlantic salmon embryos using specific complementary RNA probes and in situ hybridization. For example, co-ordinated embryonic expression patterns were revealed for six salmon MRFs (myod1a, myod1b, myod1c, myog, mrf4, myf5), as well as markers of distinct MPC populations (pax7, smlc1), providing insight into the regulatory networks governing myogenesis in a tetraploid teleost. Furthermore, it was shown that Atlantic salmon fst1 was expressed concurrently to pax7 in a recently characterised MPC population originating from the anterior domain of the epithelial somite, which is functionally analogous to the amniote dermomyotome. In another experiment, the individual expression domains of three Atlantic salmon myod1 paralogues were shown to together recapitulate the expression of the single myod1 gene in zebrafish, consistent with the partitioning of ancestral cis-acting regulatory elements among salmonid myod1 duplicates. Additionally, the in situ expression of cee a novel and highly conserved eukaryotic gene was revealed for the first time in a vertebrate and was consistent with an important role in development including myogenesis.
Additionally, Atlantic salmon were reared at 2, 5, 8 or 10 ºC solely to a defined embryonic stage, which was just subsequent to the complete pigmentation of the eye. After this time, animals were provided an equal growth opportunity. Remarkably, changing temperature during this short developmental window programmed the growth trajectory throughout larval and adult stages. While 10 and 8 ºC fish were larger than those reared at 2 and 5 ºC at the point of smoltification, strong compensatory growth was subsequently observed. Consequently, after 18 months of on growing, size differences among 5, 8 and 10 ºC fish were not significant, although each group was heavier than 2 ºC fish. Furthermore, significant embryonic-temperature induced differences were observed in the final muscle fibre phenotype, including the number, size distribution and myonuclear density of muscle fibres. A clear optimum for the final muscle fibre number was observed in 5 ºC fish, which was up to 17% greater than other treatments. In a sub-sample of embryos, temperature induced heterochonies were recorded in the expression of some MRFs (myf5, mrf4) but not others (myod1a, myog). These results allowed the proposition of a potential mechanism explaining how temperature can program the muscle phenotype of adult teleosts through modification of the somitic external cell layer, a source of MPCs throughout teleost ontogeny
Composition, structure of ichthyofauna and biological characteristics of fish populations of Lake Bolshoe Krasnoe (Solovetsky Archipelago, the White Sea)
No full textThe data of long-term studies (1965–2023) of the ichthyofauna of Lake Bolshoe Krasnoe have been summarized and systematized. Lake occupies a key position in the main lake-canal system of Bolshoy Solovetsky Island. The fish community of the lake is represented by six species, five native ones (the northern pike, burbot, the European perch, common roach, and the Eurasian ruffe) and one acclimatized (vendace). The formation of the lake ichthyofauna was influenced by abiotic and trophic characteristics of the reservoir, primarily the temperature regime, availability and amount of food. Specific responses of different fish populations to environmental factors are noted, manifested in a decrease/increase in growth rate. No fundamental differences have been found since 1965 for the fish population characteristics in Lake Bolshoe Krasnoe, which indicates the resilience of this island freshwater ecosystem to observed environmental factors
Interferon receptor recognition peptides enhance the biological potency of interferon alphas
No full textAbstractBased on our earlier studies that defined three strategic regions in the Type 1 interferon (IFN) molecule associated with receptor interactions and biological activity, three IFN receptor recognition peptides (IRRP) were synthesized, with amino acid sequences CLKDRHD (IRRP) were synthesized, with amino (IRRP2) and YFQRITLYLTEKKYSPCA (IRRP3) and examined for biological effectiveness. In cell surface receptor binding studies, the binding capacity of cells for IFN-αs was increased in the presence of the IRRPs. Increased receptor occupancy resulted in increased phosphorylation-activation of the transcription factor ISGF3 and enhanced antiviral activity. The potentiating effect on IFN-induced growth inhibition was less marked. These data suggest that the IRRPs may influence the biological potency of IFN-α by facilitating accessibility to cell surface receptor components. The IRRPs may function to increase the number of low affinity receptor-ligand interactions necessary to initiate receptor oligomerization, thereby catalysing the formation of high IFN-receptor complexes
Estruturas das comunidades de peixes recifais em ilhas oceânicas do atlântico e pacífico oriental
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas. Programa de Pós-Graduação em Ecologia, Florianópolis, 2013As ilhas oceânicas, apesar de representarem uma pequena fração dos ambientes marinhos do planeta, tem contribuido para o entendimento de processos ecológicos e evolutivos. No entanto, Abstract: Oceanic islands, although they represent a small fraction of marine environments on the planet, have contributed to understanding the ecological and evolutionary processes. However, <10% of the studies that include oceanic islands in their analyzes approach the marine systems. This lack of knowledge is further aggravated due to over exploitation of marine environments in the last century. Given this lackof information and using the reef fish as biological models, were evaluated some assumptions about the structure of marine communities on oceanic islands, such as: 1) taxonomic differences between provinces isolated by geographical barriers, 2) the relationship between species richness, area and degree of isolation, 3) the relative importance of local and regional endemic species to the composition of the assemblies and 4) the influence of biotic, abiotic and human activities on the richness,density, biomass and trophic structure of reef fish.The study area comprised eleven tropical oceanic islands and one subtropical, located between latitudes 28 ° N and 22 ° S, five islands inthe eastern Pacific (Revillagigedos, Cocos, Clipperton, Malpelo and Galapagos), four in the Western Atlantic (Archipelago St. Peter and St.Paul, Rocas Atoll, Fernando de Noronha and Trindade), two in theeastern Atlantic (Cape Verde and Sao Tome) and in the North Atlantic(Azores). Reef fish communities were sampled using underwater visualcensuses (CV) in variable areas and in species lists (LS) published. Thevariables obtained from the communities of reef fish were the richness,density and biomass of species. Physical variables such as primaryproductivity and sea surface temperature were obtained from databasesavailable online. As an indicator of human pressure was used the densityof human population in the last census reported for each island and thestatus of environmental protection given by the IUCN.The gender composition of reef fish in islands were classified into threegroups according to the degree of similarity (ANOSIM; Rglobal = 0.32, p= 0.01), this information coincides with the biogeographic provincesproposed by Briggs (1974), reflecting the intensity of biogeographicbarriers, as the Isthmus of Panama (IP) and Barrier Central Atlantic(BCA) in the separation of the composition of genres. The curves of species richness vs. area showed a positive correlation (R2CV: R2LE and0.29: 0.55), confirming the pattern observed by MacArthur & Wilson(1967) in their study of island biogeography. However, to the degree of isolation there was no significant relationship, despite a negative trend was observed (R2CV: R2LE 0.03 and 0.21.) This is possibly due to greater dispersal ability of marine organisms compared to terrestrial organisms across great distances with major frequency. The largest number ofendemic regional communities that make up the reef fishes in the eastern Pacific is related to greater isolation of this region with respectto the adjacent provinces (Caribbean and Central Pacific), IP is more effective than BCA Productivity, temperature, status of protected, and human population density, together or separately, were not able to explain the observed variations in density and biomass between the islands. However, it was observed that sites with lower biomass of reef fishes were those with the presence of resident human population, these been the archipelago of Fernando de Noronha, the archipelago of Cape Verde and Sao Tome Island. In these places, the existence of fishing, even artisanal fisheries,probably influence negatively in the biomass of large fish. This work shows that the species composition of reef fishes of oceanic islands are closely related to large-scale biogeographic factors, where as patterns ofcommunity structure (abundance, biomass) are more susceptible to local factors, including human action
Design and construction of microcontroller-based automatic fish feeding device
No full textThis paper presents the design, construction and demonstration of an automatic fish feeder. It is a microcontroller-based system. This system is designed to dispense a predetermined amount of fish feed into an aquarium at a particular time each day. The device consists of a cylindrical can, distributing tubes and a stand. The dispensing of food is controlled by the use of a stepper motor, which is situated under the canister. A timer controlled switch is used to control the time at which the motor rotates, by a program burned into the microcontroller. The fish feeder was successfully fabricated and tested. It dispenses food automatically at set preset times. It is expected that this device will enhance the fish farming efforts of the local farmers, especially the armature farmers who combine fish farming with other businesses.Includes: 4 figs.;Also includes: 9 refs
Temporal and spatial variability in 'Tetracotyle' type and metacercariae infection in the South African sardine, Sardinops sagax
No full textSpatial and temporal variation of "tetracotyle" type metacercariae infection in the eyes of the South African sardine, Sardinops sagax, was examined to elucidate the potential use of this parasite as a biological tag, and to test the hypothesis that the sardine population is divided into discrete western and southern subpopulations or stocks. Adult S. sagax specimens of 15 to 22 cm caudal length were collected monthly from five commercial fishery landing harbours to the west (St. Helena and Gans Bay) and to the east (Mossel Bay and Port Elizabeth) of Cape Agulhas in 2011 and 2012. Samples were preserved whole in 70% ethanol, or frozen, and then bagged and labelled. Fish were measured (caudal length in cm), sexed and dissected and summary statistics on the infection by "tetracotyl"e- type metacercariae in their eyes were recorded. Prevalence of infection (%), infection intensity and parasite abundance were analysed seasonally, over a period of 18 months, in fish caught to the west of Cape Agulhas and presumed to be part of the putative western stock of sardine, and in fish caught to the east of Cape Agulhas presumed to be part of the putative southern stock. Generalised linear models were used to model these three indices as dependent on stock, season, year and caudal length, where a binomial distribution was assumed for prevalence and a negative binomial distribution was assumed for infection intensity and parasite abundance. All factors contributed significantly to all models, but it was found that stock was the most significant contributor to the deviance seen in prevalence (%) and parasite abundance, and was the second most important contributor to the deviance seen in infection intensity. Fish to the west of Cape Agulhas were found to have significantly higher parasite loads in comparison to fish from the east of Cape Agulhas (p< 0.001). Season was the second most significant contributor to the deviance seen in prevalence and abundance, and was the most important contributor to the deviance seen in infection intensity, indicating that a seasonal signal was present. This seasonal signal was slightly delayed in fish from the putative southern stock in comparison to those from the putative western stock. Interannual differences in infection rates were also observed, being higher in 2012 compared to 2011. These results suggest that """"tetracotyle- type metacercariae can be used as a biological tag in stock discrimination studies and that, despite temporal variability, the clear spatial difference in the distribution of infection of S. sagax by """"tetracotyle- type metacercariae supports the hypothesis of western and southern stocks of sardine off the coast of South Africa
Environmental influence on marine pelagic fish: Evidence from bioeconomic modelling
No full textEnvironmental factors other than fishing effort, contribute to influencing marine pelagic fish population
dynamics and abundance. There is evidence from environmental modelling and bioeconomic analysis of the
Ghanaian marine inshore pelagic fisheries. Ghana is a West African country and lies on the Greenwich Meridian.
It is bordered at the South by the Gulf of Guinea. The official language of Ghana is English, but is surrounded by
French speaking countries. The inshore fishery is a multi-specie, multi-fleet fishery, consisting of artisanal and
inshore purse seine fleets. The coastal inhabitants depend mainly on the marine fisheries as source of
employment and livelihood. Fisheries constitute 5% of Agriculture GDP. The two fisheries types in the inshore
sector comprise the artisanal and inshore commercial fleet. The artisanal fleet are highly labour intensive and use
dugout canoes with average engine power of 40HP. The purse seine fleet are relatively capital intensive and
more commercial. The boats have wooden hull and have average horsepower of 230 HP. The average vessel
capacity unit of a boat is estimated to be 136.8. Both canoes and the commercial purse seine fleet compete to
exploit the same inshore pelagic fish resources within the Ghanaian EEZ. The problem is that the current stock
level has dwindled and this is attributed to overexploitation and influences of the environment. Bioeconomic
models using aggregated landings and effort data help to capture changes in multi-species fisheries (Hilborn and
Walters, 1992). Environmental factors such as temperature and salinity are feasible when jointly incorporated in
bioeconomic models. The mean monthly and annual variables and deviations from the mean are attached
(Appendix A1 and A2) for comparison.Unpublishe
A simplicial algorithm for the nonlinear stationary point problem on an unbounded polyhedron
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