Changes in the structure and function of the North Sea fish foodweb, 1973-2000, and the impacts of fishing and climate   总被引：1，自引：0，他引：1  

Heath  Michael R. 《ICES Journal of Marine Science》2005,62(5):847-868

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Regional variability in the trophic requirements of shelf sea fisheries in the Northeast Atlantic, 1973-2000     

Heath  Michael R. 《ICES Journal of Marine Science》2005,62(7):1233-1244

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A method for estimating the "position accuracy" of acoustic fish tags     

Ehrenberg  John E.; Steig  Tracey W. 《ICES Journal of Marine Science》2002,59(1):140-149

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Stable isotope analysis of some representative fish and invertebrates of the Newfoundland and Labrador continental shelf food web   总被引：3，自引：1，他引：3  

Graham D. Sherwood  George A. Rose 《Estuarine, Coastal and Shelf Science》2005,63(4):537-549

We examined stable carbon and nitrogen isotopic signatures of 17 fish and 16 invertebrate taxa common to the Newfoundland and Labrador (NL) continental shelf food web. Particular sampling emphasis was placed on Atlantic cod (Gadus morhua) and related prey species (e.g. shrimp, Pandalus borealis, and capelin, Mallotus villosus). We found highly significant (p < 0.0001) differences between near-shore (bays) and offshore (shelf edge) δ¹⁵N signatures for cod, ‘other fish’ (pooled) and invertebrates (pooled). In contrast, there were only minor differences in δ¹³C signatures of ‘other fish’ (p < 0.05) and no difference for cod and invertebrates among the two habitats. We sampled at two times of the year (January and June) and found no systematic effect of season on both δ¹³C and δ¹⁵N in cod, ‘other fish’ and invertebrates. We calculated isotopic fractionation factors for cod from the entire shelf (mixed diet) and for cod with diets composed mainly of capelin or shrimp. These values ranged between 2.2‰ and 3.9‰ for δ¹⁵N and −0.4‰ and 0.8‰ for δ¹³C and, for δ¹⁵N, may reflect diet-related differences in bioenergetic status. We discuss potential mechanisms for near-shore versus offshore enrichment of δ¹⁵N signatures, and demonstrate the implications of this spatial variation on δ¹⁵N-derived trophic position estimates.  相似文献   

Parental effects on early life history traits of haddock Melanogrammus aeglefinus     

Nikolaus Probst  W.; Kraus  Gerd; Rideout  Rick M.; Trippel  Edward A. 《ICES Journal of Marine Science》2006,63(2):224-234

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Oil spill fishery impact assessment modeling: The fisheries recruitment problem     

Mark Reed  Malcolm L. Spaulding  Ernesto Lorda  Henry Walker  Saul B. Saila 《Estuarine, Coastal and Shelf Science》1984,19(6):591-610

A model to assess the impact of oil spill on fisheries, consisting of an oil spill fates model, a continental shelf hydrodynamics model, an ichthyoplankton transport and fates model, and a fish population model, has been applied to the Georges Bank-Gulf of Maine region to estimate the impact of oil spills on several important commercial fisheries. The model addresses direct impacts of oil on a fishery through hydrocarbon-induced egg and larval mortality. This early life stage mortality is estimated by dynamically mapping the spatial intersection of the surface and subsurface oil concentrations resulting from the spill with the developing eggs and larvae. Ichthyoplankton entering an area with hydrocarbon concentrations in excess of a specified threshold are assumed lost. Model output is given in terms of differential catch, comparing the non-impacted and the hydrocarbon impacted fisheries. Difficulties in establishing stock-recruit relationships, and the inability to predict first year survival even one year ahead make the quantification of absolute catch losses impossible. Output of the model system discussed here is therefore limited to relative rather than absolute catch losses.The paper is organized to demonstrate first the importance of the recruitment question to impact estimation, second that a modeling methodology is necessary to evaluate impacts given the magnitude of unexplained observed recruitment variability, and third a stochastic solution to the problem which places impact estimates in the context of a probability distribution. Lastly, the model system is applied to the problem of attaining better early life history mortality estimates, to ultimately improve impact estimation capabilities.  相似文献   

Relationship Between the Spatiotemporal Distribution of Dominant Small Pelagic Fishes and Environmental Factors in Mauritanian Waters     

Ebango Ngando  Narcisse  Song  Liming  Cui  Hongxing  Xu  Shuangquan 《中国海洋大学学报(英文版)》2020,19(2):393-408

The relationship between the spatiotemporal distribution of three dominant small pelagic fishes,including chub mackerel(Scomber japonicus),horse mackerel(Trachurus trecae)and round sardinella(Sardinella aurita),and the environmental factors in Mauritanian waters were analyzed by using 4 years of logbook data of commercial purse seine fisheries to improve the efficiency of fishery and management of sustainable exploitation.A Tweedie-generalized additive model(GAM)of 8-day average catches and the monthly geostatistical analysis of daily catches were used in this study to analyze the influence of environmental factors on catch per unit of effort(CPUEs)and to map the spatial distribution of three mixed dominant small pelagic fishes,respectively.A 10'×10' grid was used,and environmental factors were processed from remote sensing,including 8-day average sea surface temperature(SST),the nearest distance between SST fronts and CPUE position(Df),chlorophyll-a(Chl-a)concentration,salinity,and eddy kinetic energy.Results showed that 1)the distribution of three dominant small pelagic fishes might be related to the intensity of upwelling in Mauritanian waters;2)oceanic fronts might play a key role in the ecology of chub mackerel,horse mackerel,and round sardinella;3)Chl-a concentration might be associated with the feeding grounds of chub mackerel;4)the target species distribution appeared sensitive to gradient changes in the amount of salinity;5)three zones(northern,central,and southern)with variable abundances were delineated;and 6)a high concentration of the center of gravity in the central zone might be related to the strong upwelling of nutrient-rich waters.This study can provide new insights to enhance the fishery efficiency and sustainable exploitation management of purse seiners in certain area off Mauritania.  相似文献   

Past and present state of the ichthyofauna of Lake Lugano     

Rudolf Müller  Hans Jürg Meng 《Aquatic Sciences - Research Across Boundaries》1992,54(3-4):338-350

The evolution of the ichthyofauna of Lake Lugano (Lago di Lugano) during the past 120 years is characterized by the introduction of eight new fish species and by the possibly natural addition of the blenny (Blennius fluviatilis) in recent years. Introduced Salmonids such as charr (Salvelinus alpinus) and whitefish (Coregonus sp.) have established strong populations during the first half of this century, but have declined drastically thereafter. Likewise, the population of the native shad (Alosa fallax lacustris) has diminished significantly. A hydroacoustic survey of the pelagic fish stock of Lake Lugano in 1989 revealed the presence of a dense bleak (Alburnus albidus) population at 0 to 14 m depth. No other fish were found to be present in the pelagic zone. Oxygen and temperature distributions seem to confine the bleak to the uppermost layer in summer. In winter, very few fish were located by echosounding. Growth of bleak and roach (Rutilus rubilio) was difficult to interpret since data for comparison are lacking. Growth of perch (Perca fluviatilis) in the littoral zone was found to be slower than in other eutrophic lakes, for no obvious reason. Possible ways of restructuring the pelagic fish community are discussed.  相似文献   

A fishery in a changing lake environment: The naked carpGymnocypris przewalskii (Kessler) (Cyprinidae: schizothoracinae) in Qinghai Hu,China     

K. F. Walker  I. G. Dunn  D. Edwards  T. Petr  H. Z. Yang 《International Journal of Salt Lake Research》1995,4(3):169-222

Quinghai Hu is a large, high-altitude, saline lake in north-western China, and supports a fishery based on an endemic species of naked carp (snow trout). The fish take seven years to attain maturity and a marketable weight of 300 g, and have a lifespan of 14–21 years under the present fishery regime. They seasonally migrate from the lake to spawn over the gravel beds of inflowing rivers, but these areas have been reduced by weirs and irrigation diversions and recruitment may have declined. The population may have been affected also by a 1.85-m fall in the lake level over the past 30 years, and by associated changes in salinity. The fishery was opened to large-scale exploitation in 1958. Yields declined sharply (max. 28,523 tonnes, 1960) as the larger, older fish were removed, and then more slowly (min. 2523 tonnes, 1983). Since 1987 the fish factory has been limited to an annual quota of 1200 tonnes, taken by a fleet of four pair trawlers. Another 800 tonnes are taken by licensed fishermen, mainly using gill nets, and perhaps 1000 tonnes are taken illegally. The estimated total catch in 1992 was 3000 tonnes. New trawlers introduced in 1989–90 substantially increased the factory's catch per unit effort, and in 1990 the quota was virtually filled in one month in a zone within 20 km of the factory. Although this could suggest that the stocks will be conserved if the quota is retained, at least half of the catch in 1989–92 consisted of immature individuals. Trawling operations recently were suspended following a further decline in the catch after 1992. While the new trawlers are capable of a major increase in effort, neither the changing environment, the fish stocks or the present markets favour intensified pressure. Gillnets may provide better control over the minimum size limit and may cause less damage than trawling. Other options to improve the viability and profitability of the fishery include improvements in handling, processing and marketing. Failure to develop the fishery may encourage attempts to introduce exotic fish, at some risk to survival of the local species.  相似文献   

“鱼”背后的博弈——以近代长江上游渔业资源的保护为中心     

刘静 《地域研究与开发》2016,(1):174-180

近代长江上游地区人口迅速增长,鱼类资源开发力度增强,有时甚至成为人们赖以活命的依靠。有害渔具渔法的使用、贩卖鳅鳝、毒捕放生区域鱼类等行为使得破坏鱼类资源的问题不断凸显。与此同时,民众的放生,乡规民约和国家明令禁止捕鱼的行为,对保护鱼类资源起着积极的作用。长江上游地区鱼类资源在很长时期内并未进入国家的主流视野,对其管控力度不强,保护的目的多出于原始生命观、避免灾祸等思想。民国时期渔业经济利益逐渐受到重视,国家对鱼类资源的管控力度逐渐增强,保护目的更加多元化,维护渔业经济利益成为主要目的。  相似文献