scholarly journals Dynamics of commercial fishery at the middle stretch of the Negro river: exploitation intensity by fishing grounds

2019 ◽  
Vol 45 (4) ◽  
pp. e491
Author(s):  
Giulia Cristina dos Santos Lopes ◽  
Carlos Edwar de Carvalho Freitas
Keyword(s):  
Commercial Fishery ◽  
Negro River ◽  
Exploitation Intensity

Plant diversity and species richness of Ljubljana marsh grasslands under the influence of different cutting and fertilizing regimes

2009 ◽  
Vol 57 (2) ◽  
pp. 197-203 ◽  
Author(s):  
T. Sinkovč
Keyword(s):  
Species Richness ◽  
Plant Diversity ◽  
Grassland Management ◽  
Botanical Composition ◽  
Significant Negative Effect ◽  
Negative Effect ◽  
Cutting Regimes ◽  
N Rates ◽  
Exploitation Intensity ◽  
Plot Design

The botanical composition of grasslands determines the agronomic and natural values of swards. Good grassland management usually improves herbage value, but on the other hand it frequently decreases the plant diversity and species richness in the swards. In 1999 a field trial in a split-plot design with four replicates was therefore established on the Arrhenatherion type of vegetation in Ljubljana marsh meadows in order to investigate this relationship. Cutting regimes (2 cuts — with normal and delayed first cut, 3 cuts and 4 cuts per year) were allocated to the main plots and fertiliser treatments (zero fertiliser — control, PK and NPK with 2 or 3 N rates) were allocated to the sub-plots. The results at the 1 st cutting in the 5 th trial year were as follows: Fertilising either with PK or NPK had no significant negative effect on plant diversity in any of the cutting regimes. In most treatments the plant number even increased slightly compared to the control. On average, 20 species were listed on both unfertilised and fertilised swards. At this low to moderate level of exploitation intensity, the increased number of cuts had no significant negative effect on plant diversity either (19 species at 2 cuts vs. 20 species at 3 or 4 cuts). PK fertilisation increased the proportion of legumes in the herbage in the case of 2 or 3 cuts. The proportion of grasses in the herbage increased in all the fertilisation treatments with an increased numbers of cuts. Fertiliser treatment considerably reduced the proportion of marsh horsetail ( Equisetum palustre ) in the herbage of the meadows. This effect was even more pronounced at higher cut numbers. The proportion of Equisetum palustre in the herbage was the highest in the unfertilised sward with 2 cuts (26.4 %) and the lowest in the NPK-fertilised sward with 4 cuts (1.4%).

Restructuring Canadian Business History: A Review EssayNORTH AMERICAN PATTERNS OF GROWTH AND DEVELOPMENT: THE CONTINENTAL CONTEXT. W.T. Easter-brook. Toronto: University of Toronto Press, 1990. xxviii, 272 pp.THE CANADIAN FUR TRADE IN THE INDUSTRIAL AGE. Arthur J. Ray. Toronto: University of Toronto Press, 1990. xviii, 283 pp.TIMOTHY EATON AND THE RISE OF HIS DEPARTMENT STORE. Joy L. Santink. Toronto: University of Toronto Press, 1990. xii, 319 pp.WORKING IN STEEL: THE EARLY YEARS IN CANADA, 1883-1935. Craig Heron. Toronto: McClelland and Stewart, 1988. 223 pp.THE DEVELOPMENT OF THE PACIFIC SALMON CANNING INDUSTRY: A GROWN MANS GAME. Ed. and Intro. Dianne Newell. Montreal/Kingston: McGill-Queen’s University Press, 1989. xvii, 303 pp.THE COMMERCIAL FISHERY OF THE CANADIAN GREAT LAKES. A.B. McCullough. Ottawa: Environment Canada/ Canadian Parks Service, 1989. 153 pp.IN WHOSE INTEREST? QUEBEC’S CAISSES POPULAIRES 1900 1945. Ronald Rudin. Montreal/Kingston:McGilTQueen’s University Press, 1990. xvii, 185 pp.CO-OPERATIVE ORGANIZATIONS AND CANADIAN SOCIETY: POPULAR INSTITUTIONS AND THE DILEMMAS OF CHANGE. Ed. Murray E. Fulton. Toronto: University of Toronto Press, 1990. xiv, 345 pp.

1992 ◽  
Vol 26 (4) ◽  
pp. 169-178
Author(s):  
Graham D. Taylor
Keyword(s):  
Pacific Salmon ◽  
Early Years ◽  
Business History ◽  
Commercial Fishery ◽  
Environment Canada ◽  
Canadian Society ◽  
University Of Toronto ◽  
Industrial Age ◽  
The Pacific ◽  
Canning Industry

scholarly journals A review of recent studies on the life history and ecology of European cephalopods with emphasis on species with the greatest commercial fishery and culture potential

2021 ◽  
Vol 236 ◽  
pp. 105847
Author(s):  
F. Lishchenko ◽  
C. Perales-Raya ◽  
C. Barrett ◽  
D. Oesterwind ◽  
A.M. Power ◽  
...  
Keyword(s):  
Life History ◽  
Commercial Fishery

scholarly journals Ichthyological ethnoknowledge of the “piabeiros” from the Amazon region, Brazil

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Daniel da Silva Ladislau ◽  
Maiko Willas Soares Ribeiro ◽  
Philip Dalbert da Silva Castro ◽  
Jackson Pantoja-Lima ◽  
Paulo Henrique Rocha Aride ◽  
...  
Keyword(s):  
Fish Species ◽  
Local Ecological Knowledge ◽  
Middle Part ◽  
Ornamental Fish ◽  
Ecological Knowledge ◽  
Structured Interviews ◽  
Economic Activities ◽  
Negro River ◽  
Artisanal Fishers ◽  
Ecological Aspects

Abstract Background The capture of ornamental fish is one of the main economic activities of riverine families in the Amazon. However, studies regarding the local ecological knowledge of workers in this activity are still incipient. In view of this, we have studied and explored the local ecological knowledge of artisanal fishers who specialize in the capture of fish for the aquarium trade in the middle part of the Negro River basin and investigated issues related to the ecological aspects of the fish species that are targeted by this trade in the region. Methods Therefore, we conducted semi-structured interviews and applied questionnaires to artisanal fishers of ornamental fish (N = 89), from the municipality of Barcelos, from January to April 2016. Results In total, 41 popular names were cited, which correspond to four ethnocategories and 10 families. The main species were Paracheirodon axelrodi (12.5%), Hemigrammus bleheri (8.3%), Ancistrus dolichopterus (6.4%), Symphysodon discus (5.3%), and Potamotrygon motoro (3.8%). According to the fishers, the species of fish known in the region as “piabas” have a preference for living in clusters (28.9%) and carry out migratory movements (26.1%). The diet of local fish species reported by fisheries is diverse, though mainly based on periphyton (42.2%), and the reproductive cycle directly influenced by the period of flooding of rivers in the region (37.6%) Conclusion Our study revealed that the fishers possess information on the ecological aspects of local ornamental fish species, many of which are consistent with scientific literature. The information presented may assist in the decision-making process for the management of local fishery resources and contribute to the resumption of growth and sustainability in the capture of ornamental fish.

Dynamics and Exploitation of Mature Walleyes, Stizostedion vitreum vitreum, in the Nipigon Bay Region of Lake Superior

1968 ◽  
Vol 25 (7) ◽  
pp. 1347-1376 ◽  
Author(s):  
R. A. Ryder
Keyword(s):  
Lake Trout ◽  
Lake Superior ◽  
Total Mortality ◽  
Inland Waters ◽  
Commercial Fishery ◽  
Sea Lampreys ◽  
Wood Fibres ◽  
High Concentrations ◽  
Trout Fishery ◽  
Hexagenia Limbata

Walleye stocks in Nipigon Bay of Lake Superior were homogeneous with those in tributary inland waters but were discrete from Black Bay stocks. Returns from 2200 tagged walleyes in Lake Superior and tributary inland waters between 1955 and 1958 varied from 7.8 to 31.0% for 2 years after release. The commercial fishery in Lake Superior recovered 64.9% of the tags, the sports fishery in inland waters captured 27.6%. Fish tagged in the Nipigon River travelled a mean distance of 11.8 miles from the point of release and were recovered in 191 days (average). Total mortality rates for Nipigon Bay walleyes were 55.0% (1955–57). Mature walleyes on the spawning grounds in the Nipigon River in 1957 were estimated at 22,000, and fish in Nipigon Bay over 14 inches (total length) the same year at 41,000. All male walleyes were mature at 15 inches and females at 18 inches. Walleyes exploitation rates increased with the decline of the lake trout fishery. Wounding and scarring rates by sea lampreys increased during 1955–57 but never exceeded 1.0% on adult walleyes. Severe pollution on the west side of Nipigon Bay originated from a kraft mill. High concentrations of total solids and dense sedimentation of wood fibres created an environment unfavourable to Hexagenia limbata and Pontoporeia affinis. The recent elimination of the walleye fishery in Nipigon Bay is most likely attributable to industrial pollution rather than to overexploitation or sea lamprey predation.

Influence of climatic changes on the parasites of Atlantic cod Gadus morhua off coastal Labrador, Canada

2006 ◽  
Vol 80 (2) ◽  
pp. 193-197 ◽  
Author(s):  
R.A. Khan ◽  
C.V. Chandra
Keyword(s):  
North Atlantic ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Age Groups ◽  
Climatic Conditions ◽  
Otter Trawl ◽  
Commercial Fishery ◽  
Metazoan Parasites ◽  
Mean Values ◽  
The North

AbstractA study was conducted in 2000 and 2003, following the collapse of the commercial fishery in 1990, to compare metazoan parasites of Atlantic cod Gadus morhua, captured off coastal Labrador, with samples taken in 1980 and 1986. Fish were captured by otter trawl offshore in the North Atlantic Fish Organisation subarea 2J. Parasites were removed from the digestive tract, stained, identified and compared between the different groups. Both the prevalence and mean abundance of trematodes, larval nematodes and E. gadi were significantly lower in fish taken in 2000 and 2003 than in 1980. While mean values of trematodes and nematodes declined in 1986, those of Echinorhynchus gadi remained unchanged in 1986 and 1990. Four-year-old cod sampled in 1990 harboured significantly fewer E. gadi than older age groups. The most commonly occurring trematodes included Podocotylereflexa, Lepidapedon elongatum, Derogenes varicus and Hemiurus levinseni while the larval nematode, Anisakis sp. was predominant. Comparison of offshore samples taken in 2000 and 2003 with others taken in previous years suggests an overall decline of parasites coincident with a change in climatic conditions, the absence of a major food source, namely capelin Mallotus villosus, of cod and ultimately the decline of the Labrador population.

Floristic variation across 600 km of inundation forests (Igapó) along the Negro River, Central Amazonia

Hydrobiologia ◽  
2012 ◽  
Vol 729 (1) ◽  
pp. 229-246 ◽  
Author(s):  
Juan Carlos Montero ◽  
Maria Teresa Fernandez Piedade ◽  
Florian Wittmann
Keyword(s):  
Negro River ◽  
Inundation Forests ◽  
Central Amazonia ◽  
Floristic Variation

Hydrochemical aspects of the negro river, patagonia, argentina

1980 ◽  
Vol 5 (2) ◽  
pp. 181-186 ◽  
Author(s):  
Pedro J. Depetris
Keyword(s):  
Negro River
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