In order to assess effects of Summer Fishing Moratorium (SFM) in Daya Bay, variations in stock density, fish diversity, fish species composition, fish body length and weight, and bio-environments during the pre-SFM (M...In order to assess effects of Summer Fishing Moratorium (SFM) in Daya Bay, variations in stock density, fish diversity, fish species composition, fish body length and weight, and bio-environments during the pre-SFM (May in 2015) and post-SFM (August in 2015) in Daya Bay were analyzed, based on trawl survey data. Results showed that the average stock density in the post-SFM was 5.65 times of that in the pre-SFM, and the average species numbers in the post-SFM was 1.76 times of that in the pre-SFM. Analysis of fish body length and weight indicated that fish grew faster during the SFM, and body weight was more uniform in the post-SFM. In the post-SFM, the Shannon-Wiener diversity index and Pielou evenness index increased by 0.36 and 0.14, respectively, indicating that the fish biodiversity and community structure improved. SFM alleviated fishing intensity, recovered and conserved coastal fish resource. In order to improve efficiency and impacts of SFM and to promote sustainable development of coastal fish resource, prolonging the time of SFM, reducing the number of coastal fishing boats and enforcing the conservation of fish resources were suggested.展开更多
[Objective] The paper was to quantitatively evaluate the maintenance effect of summer fishing moratorium （SFM） in Daya Bay. [Method]Based on satellite remote sensing and trawl surveys, the changes in sea surface tem...[Objective] The paper was to quantitatively evaluate the maintenance effect of summer fishing moratorium （SFM） in Daya Bay. [Method]Based on satellite remote sensing and trawl surveys, the changes in sea surface temperature （SST） , chlorophyll a （Chla） concentration, catchper unit effort （CPUE）, biodiversity, species composition, body length and weight of total catch in Daya Bay before SFM （May 2015） and after SFM（August 2015） were comparatively analyzed. [Result] The CPUE of total catch mainly distributed from 0-10 kg/h before SFM to 0-40 kg/h afterSFM. The average body length and weight of catches increased, indicating that the growth rate of catches was accelerated. The indices of ShannonWiener diversity index （H忆） and Pielou evenness index（J忆） increased by 0.36 and 0.14, respectively, indicating that the community structure wasimproved. The biomass spectra of fishery resources community suggested that the slopes of normalized biomass spectra after SFM was greater than-1, and the biomass of fishery resources increased with the increase of individual body weight after SFM. SFM reduced offshore fishing intensity,recovered and conserved the fishery resources in Daya Bay. [Conclusion] In order to improve the SFM system and promote the sustainable development of coastal fishery resources, it is suggested to prolong the time of SFM appropriately, reduce the number of coastal fishing boats, and strengthen the conservation of fish resources.展开更多
Kenya’s public forest sector plantations have been the main source of roundwood for wood-based industries but several factors have reduced its capacity to meet increasing demands, resulting in huge deficits. The grow...Kenya’s public forest sector plantations have been the main source of roundwood for wood-based industries but several factors have reduced its capacity to meet increasing demands, resulting in huge deficits. The growth of small-holder forestry over the last three decades has demonstrated the potential to supplement the deficits. The imposed logging moratorium in public and community forests in 2002-2012 and 2018 not only opened markets for small-holder tree growers but also increased demand pressure from various wood consumers. This paper presents an assessment of the status of farm-based wood resources three years within the latest moratorium period and the potential of farm tree resources to complement wood from public forest plantations. Data were collected from 56 households using semi-structured interviews, key informants interviews, and a rapid assessment of standing and harvested trees from 146 on-farm plots. The main commercial tree species found on the farms were;Cupressus lusitanica, Eucalyptus sp., Grevillea robusta, Pinus patula, and Acacia mearnsii. Eucalypts were the most planted trees with an average land size of 1.08 ha. The farm tree resources have sustained some level of wood demand since the moratorium, as indicated by the high volume of wood harvested. The study found that about 40% of current wood resources consisted of trees less than 5 years, and most harvests were of small diameter classes which are essentially juvenile wood and are unsuitable for structural and furniture use. Furthermore, most small-scale farmers lack appropriate silvicultural and management knowledge, preferring smaller growing spacing as shown by the high planting density of 1659 stems·ha<sup>-1</sup> and also use of inferior germ-plasm, with implications on the quality of wood from farms. It is recommended that rigorous capacity building on tree growing and management techniques be undertaken and a progressive and supportive policy framework on harvesting and trade of trees on-farm be developed.展开更多
为定量评估大亚湾伏季休渔的养护效果,以渔业环境卫星遥感和拖网调查相结合的方法,对大亚湾休渔前(2015年5月)和休渔后(2015年8月)海表温度和叶绿素a浓度、总渔获物的单位捕捞努力量渔获量(catch per unit effort,CPUE)、生物多样性、...为定量评估大亚湾伏季休渔的养护效果,以渔业环境卫星遥感和拖网调查相结合的方法,对大亚湾休渔前(2015年5月)和休渔后(2015年8月)海表温度和叶绿素a浓度、总渔获物的单位捕捞努力量渔获量(catch per unit effort,CPUE)、生物多样性、种类组成和体长、体质量变动进行了对比分析。结果表明,伏季休渔后,总渔获物CPUE的主要分布范围从休渔前的0~10 kg·h–1提高到休渔后的0~40 kg·h–1。渔获物平均体长和体质量增加,生长速率加快。渔业资源Shannon-Wiener多样性指数(H')和Pielou均匀度指数(J')分别增加了0.36和0.14,群落结构有所改善。渔业资源群落的生物量谱研究表明,休渔后标准化生物量谱线性回归系数大于–1,生物量随个体体质量的增加而增加。伏季休渔降低了近海的捕捞强度,恢复和养护了大亚湾的渔业资源。建议采取适当延长休渔期、减控近海渔船数、加强资源养护等措施,进一步完善休渔制度,促进近海渔业资源的可持续发展。展开更多
文摘In order to assess effects of Summer Fishing Moratorium (SFM) in Daya Bay, variations in stock density, fish diversity, fish species composition, fish body length and weight, and bio-environments during the pre-SFM (May in 2015) and post-SFM (August in 2015) in Daya Bay were analyzed, based on trawl survey data. Results showed that the average stock density in the post-SFM was 5.65 times of that in the pre-SFM, and the average species numbers in the post-SFM was 1.76 times of that in the pre-SFM. Analysis of fish body length and weight indicated that fish grew faster during the SFM, and body weight was more uniform in the post-SFM. In the post-SFM, the Shannon-Wiener diversity index and Pielou evenness index increased by 0.36 and 0.14, respectively, indicating that the fish biodiversity and community structure improved. SFM alleviated fishing intensity, recovered and conserved coastal fish resource. In order to improve efficiency and impacts of SFM and to promote sustainable development of coastal fish resource, prolonging the time of SFM, reducing the number of coastal fishing boats and enforcing the conservation of fish resources were suggested.
基金Supported by Natural Science Foundation of Guangdong Province(2018A030313120)Basal Research Fund of Central Public-interest Scientific Institutions in Chinese Academy of Aquatic Sciences(2018HY-ZD0104)+1 种基金State Key Laboratory of Tropical Oceanography,South China Sea Institute of Oceanology,Chinese Academy of Sciences(LTO1806)National Key Technology R&D Program(2012BAD18B01)
文摘[Objective] The paper was to quantitatively evaluate the maintenance effect of summer fishing moratorium （SFM） in Daya Bay. [Method]Based on satellite remote sensing and trawl surveys, the changes in sea surface temperature （SST） , chlorophyll a （Chla） concentration, catchper unit effort （CPUE）, biodiversity, species composition, body length and weight of total catch in Daya Bay before SFM （May 2015） and after SFM（August 2015） were comparatively analyzed. [Result] The CPUE of total catch mainly distributed from 0-10 kg/h before SFM to 0-40 kg/h afterSFM. The average body length and weight of catches increased, indicating that the growth rate of catches was accelerated. The indices of ShannonWiener diversity index （H忆） and Pielou evenness index（J忆） increased by 0.36 and 0.14, respectively, indicating that the community structure wasimproved. The biomass spectra of fishery resources community suggested that the slopes of normalized biomass spectra after SFM was greater than-1, and the biomass of fishery resources increased with the increase of individual body weight after SFM. SFM reduced offshore fishing intensity,recovered and conserved the fishery resources in Daya Bay. [Conclusion] In order to improve the SFM system and promote the sustainable development of coastal fishery resources, it is suggested to prolong the time of SFM appropriately, reduce the number of coastal fishing boats, and strengthen the conservation of fish resources.
文摘Kenya’s public forest sector plantations have been the main source of roundwood for wood-based industries but several factors have reduced its capacity to meet increasing demands, resulting in huge deficits. The growth of small-holder forestry over the last three decades has demonstrated the potential to supplement the deficits. The imposed logging moratorium in public and community forests in 2002-2012 and 2018 not only opened markets for small-holder tree growers but also increased demand pressure from various wood consumers. This paper presents an assessment of the status of farm-based wood resources three years within the latest moratorium period and the potential of farm tree resources to complement wood from public forest plantations. Data were collected from 56 households using semi-structured interviews, key informants interviews, and a rapid assessment of standing and harvested trees from 146 on-farm plots. The main commercial tree species found on the farms were;Cupressus lusitanica, Eucalyptus sp., Grevillea robusta, Pinus patula, and Acacia mearnsii. Eucalypts were the most planted trees with an average land size of 1.08 ha. The farm tree resources have sustained some level of wood demand since the moratorium, as indicated by the high volume of wood harvested. The study found that about 40% of current wood resources consisted of trees less than 5 years, and most harvests were of small diameter classes which are essentially juvenile wood and are unsuitable for structural and furniture use. Furthermore, most small-scale farmers lack appropriate silvicultural and management knowledge, preferring smaller growing spacing as shown by the high planting density of 1659 stems·ha<sup>-1</sup> and also use of inferior germ-plasm, with implications on the quality of wood from farms. It is recommended that rigorous capacity building on tree growing and management techniques be undertaken and a progressive and supportive policy framework on harvesting and trade of trees on-farm be developed.
文摘为定量评估大亚湾伏季休渔的养护效果,以渔业环境卫星遥感和拖网调查相结合的方法,对大亚湾休渔前(2015年5月)和休渔后(2015年8月)海表温度和叶绿素a浓度、总渔获物的单位捕捞努力量渔获量(catch per unit effort,CPUE)、生物多样性、种类组成和体长、体质量变动进行了对比分析。结果表明,伏季休渔后,总渔获物CPUE的主要分布范围从休渔前的0~10 kg·h–1提高到休渔后的0~40 kg·h–1。渔获物平均体长和体质量增加,生长速率加快。渔业资源Shannon-Wiener多样性指数(H')和Pielou均匀度指数(J')分别增加了0.36和0.14,群落结构有所改善。渔业资源群落的生物量谱研究表明,休渔后标准化生物量谱线性回归系数大于–1,生物量随个体体质量的增加而增加。伏季休渔降低了近海的捕捞强度,恢复和养护了大亚湾的渔业资源。建议采取适当延长休渔期、减控近海渔船数、加强资源养护等措施,进一步完善休渔制度,促进近海渔业资源的可持续发展。
