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1.
为研究和控制野生鸟类传播禽流感,对山西省鸟类分布情况进行了研究和分析。山西省鸟类物种记录为335种,大约有12.3%的鸟生活在村落附近,10.3%的鸟类生活在农田、水田附近,12.8%的鸟类生活在水域周围,23.5%的鸟类出现在灌木草丛附近,这些鸟类均可与家禽及人类接触,从而传播禽流感病毒;其余41.1%的鸟类生活在山林、悬崖、树林等与家禽接触不到的地方。  相似文献
2.
根据大竹县农村散养畜禽寄生虫病的感染情况及流行病学特点,提出了畜禽寄生虫病感染情况调查方案和驱虫试验。  相似文献
3.
Artificial structures can protect fish against predation by cormorants (Phalacocorax spp.). However, their effectiveness in larger water bodies with different fish communities in the presence of natural vegetation still needs to be explored. Using a large‐scale field experiment with 24 ponds stocked with differently composed fish communities, the present study investigates the extent to which the effect of artificial refuges on fish is species‐specific and determined by the characteristics of the fish community. This study provides strong experimental evidence for artificial refuges protecting fish against predation from cormorants, even in the presence of submerged vegetation. The effect of refuges was, however, highly species‐specific and depended on the composition of the fish community. Strong positive effects of refuges on rudd, Scardinius erythrophthalmus (L.), and roach, Rutilus rutilus (L.), populations were observed, especially in ponds where these species dominated. Overall, the total biomass of young‐of‐the‐year, 1‐year‐old and adult rudd and roach was on average 500, 7 and 15 times lower in ponds without than in ponds with refuges, respectively. No effect of artificial refuges on other fish species was found. This study indicates that artificial refuges can facilitate the coexistence of predation vulnerable fish populations with cormorants in lakes and ponds.  相似文献
4.
  1. Breeding waterbird communities have suffered globally from the effects of anthropogenic changes in water quality (especially nutrient enrichment) in recent decades, but few studies have demonstrated the positive effects of restorative actions.
  2. Annual breeding waterbird surveys in the period 1977–2005 at two restored southern Danish lake basins (combining nutrient load reduction and biomanipulation) showed an up to five‐fold increase in abundance, and considerable changes in species richness and diversity, following restoration to clear water status in both lakes.
  3. Parallel surveys at a third lake, which retained clear water quality throughout, offering a form of natural ‘control', showed no such changes over the same time period.
  4. Consistent relationships between breeding waterbird abundance, species richness, and diversity with measures of water clarity (Secchi disc depth, chlorophyll a, and suspended matter) suggest that water clarity mainly drives the relationship; inverse relationships between these measures and total nitrogen and phosphorus were less consistent than for water clarity.
  5. The results suggest that an improvement in water clarity plays a key role in restoring breeding waterbird communities and suggest that breeding waterbirds can be indicators of the success of lake restoration projects, but more studies are needed to confirm their wider utility under a variety of conditions.
  相似文献
5.
  1. The most western little penguin colony globally, and the most northern in Western Australia (WA) is found on Penguin Island, WA. The penguins use coastal bays that are also used extensively by recreational watercraft. These penguins have been found to either dive predominantly to shallow depths of 1–5 m or to depths >8 m. It is thus hypothesized that (a) both the shallow and deeper diving penguins can potentially be disturbed or injured by these watercraft but that the risk will differ between the two diving strategies, and (b) that risk of injury for both is greater during the summer and autumn, when people are more likely to use watercraft.
  2. This was tested by attaching data loggers to little penguins during chick rearing and by investigating necropsy records. Diving activity was studied for the very shallow and relatively deeper diving penguins separately, and we considered the penguins were vulnerable to interactions with watercraft when they were within the top 2 m of the water column or at the surface.
  3. Shallow‐diving penguins executed >1,200 dives per day, 64% of dives occurred within the top 2 m, and they were vulnerable for approximately two‐thirds of their time at sea. The deeper diving penguins executed fewer dives. Almost half of dives were to ≥10 m, yet they were vulnerable for almost one‐third of their time at sea. Their post‐dive recovery was also longer. Thus, the risk of interaction from watercraft differs depending on the diving behaviour.
  4. This study highlights the potential impact to little penguins throughout Australia and New Zealand.
  相似文献
6.
Despite the importance of understanding marine bird response to prey fish, few studies have examined this relationship during winter. Over a 5‐year period, we conducted synoptic marine bird and hydroacoustic forage fish surveys during early (November) and late (March) winter to characterize the factors influencing marine bird and forage fish dynamics at two spatial scales (fish school and bay) within subarctic bays of coastal Alaska, USA. Over 40% of observed marine birds were associated with a fish school (within 150 m of a fish school), although only 20% of fish schools were associated with birds. Seasonally, we recorded significantly more schools during early winter. The marine bird community also shifted from being comprised primarily of marbled murrelets (Brachyramphus marmoratus) and large gulls (Larus spp.) in early winter to common murres (Uria aalge) in late winter. At the school level, marine birds were more likely to be associated with shallow fish schools within 500 m of shore and in smaller prey patches. At the bay level, gull abundance was positively associated with the total number of fish schools recorded, while diving birds were more abundant when fish schools were higher in the water column, in shallower bottom depths, and in areas with more eel grass habitat. Our results indicate the importance of temporal, habitat, and fish school variables as drivers of marine bird presence and abundance, underscoring the complexity of predator–prey dynamics in the marine environment during winter.  相似文献
7.
  1. Fisheries bycatch of seabirds presents a serious management problem, and relatively little is known about this problem. In the Western North Atlantic, the issue is complicated by the relatively low effort and coverage of the observer programme and the high uncertainty in species identification.
  2. The Western North Atlantic is home to many endemic and endangered seabird populations, and the impact of fishery‐caused seabird bycatch has been of high interest, especially for those species with a low population size; however, species‐specific bycatch estimates have been difficult. From 1992 to 2016, 158 seabirds were observed caught by the US Atlantic pelagic longline fleet; among them, only 80 were identified to species, 25 were identified to family, and the rest – mainly in the older records – were unidentified.
  3. In this study, ecological traits of seabirds were used to improve bycatch estimation and provide species‐specific risk analysis to all the potentially affected seabird species in this region. Bayesian state–space modelling was used to accommodate the high level of uncertainty in the species identification process.
  4. Seabird bycatch risk was found to be highly dependent on population size. The group of large seabird species was estimated to be two times as vulnerable as the group of mid‐to‐small seabird species, scavenging and plunge‐diving feeding modes were identified as imposing high bycatch risks, and spatial and temporal distribution patterns were also good indicators of bycatch risk. Based on these ecological traits, shearwaters, gulls, gannets, and petrels were identified to potentially suffer from high bycatch in this region. These species, especially those that have not been identified historically, deserve extra attention in the observer programme, and for the implementation of conservation measures of seabirds in this region.
  相似文献
8.
  1. Gillnets are used widely in fisheries throughout the world and known to cause the death of thousands of seabirds each year. Currently few practical or technical options are available to fishers for preventing seabird mortalities.
  2. The ability of little penguins (Eudyptula minor) to differentiate between different coloured netting materials was tested under controlled conditions to ascertain if changes in gillnet colour could facilitate a potential mitigation measure by improving visibility of nets.
  3. The study involved a repeated‐measures design with penguins exposed to variously coloured mono‐filament threads creating a gillnet mimic. The gillnet mimic was made up of gillnet material configured as a series of vertical lines 25 mm apart stretched tightly across a stainless steel frame that measured 1160 mm × 1540 mm and divided into two equal panel areas. The panels were placed in a large tank within an enclosure that housed 25 penguins. Penguins were able to readily access the tank and swim freely. The frame was always introduced into the tank with one panel containing a gillnet mimic, and the other panel left empty as a control.
  4. Gillnet filament colours tested were clear, green and orange. Orange coloured monofilament lines resulted in lower collision rates (5.5%), while clear and green monofilament lines resulted in higher rates of collision (35.9% and 30.8%, respectively).
  5. These results suggest that orange‐coloured lines were more apparent to the birds. Constructing nets of orange‐coloured material may be effective in reducing bycatch in gillnets set in shallow waters and high light levels where seabirds are able to identify fine colour differences.
  6. Further testing under experimental conditions, accompanied with at‐sea trials to verify effectiveness in varied light conditions is warranted, together with an assessment of the effect of gillnet colour on catch efficiency of target species.
  相似文献
9.
  1. Relatively little is known about seabird–fishery interactions (i.e. bycatch) for the U.S. North‐east and mid‐Atlantic, despite concerted efforts to document observed interactions since 1989.
  2. Fisheries observer data were used to estimate seabird–fishery interactions for 10 species and six gear types that operated within the US Northeast and mid‐Atlantic from 1996 to 2014.
  3. Hierarchical Bayes estimation was used and accounted for temporal, spatial, and operational considerations inherent in the data through post‐stratification.
  4. Over the 19‐year study period, 48 821 (coefficient of variation [CV] = 0.03) seabirds were estimated to have interacted with commercial fishing gear, resulting in an average of 2570 interactions per year.
  5. Trends in estimated interactions were explored using the marginal posterior distributions, with the majority of interactions pertaining to gillnets and shearwaters/fulmars.
  6. Comparison with previous work highlighted the need for consistency in data preparation, making it easier to compare relative trends in seabird bycatch estimates for the region.
  7. Future assessments should focus on providing context for the interaction estimates, so that population‐level impacts can be inferred and the necessary conservation measures enacted.
  相似文献
10.
  1. Commercial fishing has been identified as one of the main threats affecting the survival of most seabird species. Although seabird mortality in Argentine longline and demersal trawl fisheries has already been characterized and quantified, the interactions with pelagic trawl fisheries targeting anchovy (Engraulis anchoita Hubbs & Marini, 1935) remains unknown.
  2. The goal of this study was to characterize seabird assemblages attending pelagic trawl vessels and to analyse their interactions (i.e. contact of the birds with the vessel and/or fishing gear and by‐catch). Data were obtained by on‐board observers during three consecutive fishery runs, 2011–2013.
  3. From a total of 333 observations, seabird abundance averaged 157.3 ± 229.7 birds per haul (totalling 23 species). Procellariiform followed by Charadriiform birds were the more frequent and abundant groups. The black‐browed albatross (Thalassarche melanophris (Temminck, 1828)), shearwaters (Ardenna spp. and Puffinus spp.), white‐chinned petrel (Procellaria aequinoctialis Linnaeus, 1758), and the kelp gull (Larus dominicanus Lichtenstein, 1823) were the most frequent and abundant attending species.
  4. The seabird abundance increased when the swell and the number of neighbouring vessels decreased.
  5. Seabird interactions with the vessel and/or fishing gear occurred in approximately 70% of the observations, with most of these representing interactions with the net (92%). The estimated contact rate was 16.7 birds h?1 per haul. A total of 121 birds were by‐caught and the average mortality rate was 0.55 birds h?1 per haul. Shearwaters and Magellanic penguins (Spheniscus magellanicus (Forster, 1781)) were the main by‐caught species (101 and 12 individuals, respectively). Lower levels of mortality were recorded in black‐browed albatrosses and white‐chinned petrels.
  6. The interactions increased in the presence of fishing discards and during haulback operations.
  7. This study is relevant to the implementation of the Argentine National Plan of Action – Seabirds, as well as for the continuing certification process in the anchovy fishery.
  相似文献
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