Fisheries management scenarios: trade‐offs between economic and biological objectives

An age‐structured, population biology submodel and an economic submodel with vessel‐specific dynamics were applied to a demersal fishery in the North Aegean (NE Mediterranean) that consists of three main stocks: European hake Merluccius merluccius (L.), red mullet Mullus barbatus L. and striped red mullet Mullus surmuletus L. The Mefisto model is a bioeconomic simulation model through which the biological and economic submodels (disaggregated at the vessel level) are linked by means of a fishing mortality vector. Alternative management scenarios were built and tested based on input controls, and the performance of these strategies was examined against those of current policies. Three alternative management strategies were as follows: (1) reducing the coastal fisheries' fleet units; (2) limiting the effort level (days at sea) of the trawl fleets; and (3) changing the selectivity patterns of the trawl by increasing mesh size. The results show that for all three species, any of the three management measures (input controls) would be beneficial to both the stock and the fleets (over the medium and long terms) compared with the projections over time for the status quo. Improving the selectivity of the fishing gear proved to be more beneficial than limiting nominal effort, which was in turn more beneficial than decreasing coastal fleet size.     

Effects of dietary fish oil replacement with blended vegetable oils on growth,lipid metabolism and antioxidant capacity of subadult swimming crab Portunus trituberculatus

A 120‐day trial was conducted to assess the effects of dietary fish oil replacement with vegetable oils on growth, lipid metabolism and antioxidant capacity of subadult swimming crab Portunus trituberculatus. Five isonitrogenous and isolipidic diets were formulated to replace 0, 250, 500, 750 and 1000g/kg of fish oil with a mixture of soybean and rapeseed oil (defined as D1–D5), and each treatment had 30 replicate crabs. Dietary fish oil replacement had no significant effects on growth of the crabs, while the D3 had the highest hepatosomatic index and total lipids in hepatopancreas. The triglyceride and lipase activities in hepatopancreas increased significantly with increasing dietary fish oil replacement. The D4 had the highest levels of alkaline phosphatase (ALP) and acid phosphatase (ACP) in the hepatopancreas, as well as the haemolymph ALP, ACP and peroxidase. The highest levels of haemolymph total antioxidant capacity, catalase and malondialdehyde were detected in D1. Total n‐3 polyunsaturated fatty acids levels in hepatopancreas decreased significantly with increasing dietary fish oil replacement. In conclusion, dietary fish oil replacement had no significant effects on growth of P. trituberculatus, and 500g/kg of fish oil replacement could improve antioxidant capacity, but excessive replacement level will enhance lipid accumulation and peroxidation in the hepatopancreas.     

黄土区大型露天煤矿区生态承载力评价研究--以平朔安太堡露天煤矿为例

露天矿生态承载力的变化与矿区的污染控制、土地复垦与生态重建措施密切相关。本文根据矿区生态承载力内涵及层次特点,从生态系统弹性力、资源环境承载力及生态系统压力度3个方面提出对其进行量化的研究方法。结合高吉喜提出的生态承载力评价方法,构建了较完整的评价指标体系,利用AHP法求得各指标权重值,对矿区生态承载力状况进行静态和动态评价。研究结果表明:平朔安太堡矿区2007年的生态系统弹性力为46.836,中等稳定;资源环境承载力47.127,中等承载;生态系统压力度为1.396,承载超负荷。从动态变化趋势看,平朔安太堡矿区生态系统弹性力波动较强烈,说明矿区生态系统稳定性差,具有明显的脆弱特性;生态系统压力指数的变化说明,1999年前生态系统的压力对矿区生态系统弹性力和资源环境承载力影响较大,而1999年后影响逐渐减弱,矿区1987~2007年生态系统弹性力和资源环境承载力变化趋势相同;1997年后生态弹性力开始上升,资源环境承载力在1999年后也处于明显上升趋势。     

Effect of incubation temperature on carbohydrate digestion in important teleosts for aquaculture

The activity and capacity (activity × tissue weight) of digestive carbohydrases (total carbohydrase, α‐glucosidase, α‐amylase) was examined in vitro under a range of (more realistic) incubation temperatures (5, 18 and 25°C) and pH (7.6) more likely to be encountered during rearing, along the digestive tract of important teleost species for aquaculture (Dicentrarchus labrax, Sparus aurata, Oreochromis aureus, Oncorhynchus mykiss and Salmo salar). Results indicate, among other things, an overestimation of digestive carbohydrase levels when performing assays at 37°C, a different effect of temperature on digestive enzyme performance along the digestive tract of examined species, and the increased importance of α‐glucosidase towards carbohydrate digestion. Implications regarding the capacity of each species for carbohydrate digestion in nature, as well as feed manufacturing, are discussed.     

重庆市近10年水资源承载力时空格局动态演变研究

以生态足迹理论为基础,通过水资源生态足迹模型研究了重庆市2000～2009年水资源生态足迹和水资源承载力时空格局动态演变。结果表明,近10年来,重庆市人均水资源生态足迹和人均水资源承载力波动呈下降的趋势,水资源生态足迹从2000年的3.50hm2/人下降到2009年的2.64 hm2/人,水资源承载力从2000年的6.05 hm2/人下降到2009年的3.48 hm2/人,并在2001年和2006年达到低谷期。在空间上,重庆市水资源生态足迹和水资源承载力空间差异较为明显,都市发达经济圈和渝西走廊的水资源承载力和水资源生态足迹较低,其中最突出的为渝中区;三峡库区、渝东南水资源生态足迹和水资源承载力相对较高,其中城口县和巫溪县最为突出。此外,重庆市40个区县总体上水资源生态足迹基本低于水资源承载力,存在着生态盈余,但部分区县的水资源生态赤字仍较为严重。     

长牡蛎和福建牡蛎个体生长模型的构建及比较

长牡蛎和福建牡蛎分别是我国北方和南方沿海重要的养殖贝类。为比较分析二者的动态生长情况,实验基于动态能量收支理论（DEB）,以连续监测的水温和叶绿素a浓度为强制因子,通过现场实验、模型调试和文献查阅等方式获取模型参数,利用Python 2.7软件分别构建了桑沟湾长牡蛎、深沪湾福建牡蛎的个体生长模型,并以两种牡蛎的实测生长数据进行验证。结果显示：①所构建的DEB模型能够较好地模拟长牡蛎、福建牡蛎的个体生长情况（壳高、软组织湿重等）,模拟值与实测值之间相关性显著;②长牡蛎和福建牡蛎的温度耐受上限（T_H）、温度耐受下限（T_L）、半饱和常数（F_H）等参数存在差异,这可能与不同海域的理化环境、食物组成及牡蛎的选择性摄食有关;③在模拟周期内,受温度和食物的双重限制,长牡蛎冬季生长缓慢,而福建牡蛎处于持续增长状态,期间主要受到食物的限制。本研究结果可为后续生态系统模型构建和牡蛎养殖容量评估提供基础数据。     

急性硫化物胁迫对日本沼虾免疫和抗氧化系统的影响

日本沼虾（Macrobrachium nipponense）在硫化物浓度为0.4、1.2和4.0mg/L的水体中暴露48h,研究硫化物胁迫对其血液免疫指标和机体抗氧化能力的影响。结果表明,硫化物对日本沼虾的24、48、72、96hLC50分别为22.5、15.2、12.5、11.35mg/L。血细胞密度（THC）和吞噬活力（吞噬百分比和吞噬指数）随硫化物质量浓度升高而降低,至48h,0.4、1.2和4.0mg/L组的THC显著降低,分别为对照组的85.71%、70.75%和57.48%。各试验组沼虾的凝血时间与对照组相比延长,1.2mg/L和4.0mg/L组分别从12h和6h开始显著长于对照组（P〈0.05）。沼虾肌肉中的总抗氧化能力（T-AOC）随硫化物浓度的升高而降低,至48h,1.2mg/L和4.0mg/L组显著低于对照组（P〈0.05）。超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活力随硫化物浓度的升高而增强,至48h,1.2mg/L和4.0mg/L组的SOD活力显著高于对照组（P〈0.05）,表明日本沼虾免疫系统对低浓度硫化物有一定的耐受力;当硫化物浓度过高时,沼虾的免疫能力降低,对机体抗氧化系统产生显著影响。     

基于Ecopath模型的海州湾三疣梭子蟹增殖生态容量研究

为科学开展生态型增殖放流,对海州湾海域三疣梭子蟹(Portunus trituberculatus)开展生态容量评估。根据2018-2019年海州湾渔业资源调查数据,构建了由20个功能群组成的海州湾生态系统Ecopath模型,并对模型进行了不确定性及参数敏感性分析检验,系统分析了生态系统的总体特征、功能群间的营养关系和关键功能群,并评估了三疣梭子蟹的增殖生态容量。结果表明,Ecopath模型可信度Pedigree指数为0.482。三疣梭子蟹目前不是海州湾生态系统的关键功能群,其他底层鱼类、软体动物(Molluscs)以及底栖甲壳类(Benthic crustaceans)是海州湾生态系统的关键功能群。三疣梭子蟹生物量的增加对棘头梅童鱼(Collichthys lucidus)以及其他中上层鱼类产生正影响,对底层鱼类以及小黄鱼(Larimichthys polyactis)产生负影响;虾虎鱼科(Gobiidae)、口虾蛄(Oratosquilla oratoria)生物量的增加对三疣梭子蟹有较大负影响,多毛类(Polychaetes)生物量的增加对三疣梭子蟹有较大正影响。三疣梭子蟹的增殖...     

自由基化学改性氧化石墨烯对亚甲基蓝的吸附性能

氧化石墨烯（Graphene Oxide,GO）拥有较大的比表面积和较高的稳定性,可用来吸附水体中的多种污染物,其潜在功能稳定性具有规模化应用前景。考虑到GO在高级氧化体系中结构和形貌会发生改变,探究了经UV/H2O2和UV/过硫酸盐(Persulfate, PS)产生强氧化性自由基的体系处理后所得GOs对亚甲基蓝(Methylene Blue, MB)的吸附性能。氧化性自由基体系光源为300 W中压汞灯,30 mL GO储备液(1 mg/mL)在2种氧化体系下反应1、2、4 h后制得GOs。实验考察了不同反应条件对GOs吸附动力学的影响,傅里叶变换红外光谱(FTIR)研究了GOs氧化前后表面官能团的变化。结果显示,经UV/H2O2, UV/PS氧化1 h后,GOs表面的含氧官能团数量开始明显减少;吸附动力学过程更符合准二级动力学模型（R2>0.999）;吸附热力学过程更符合Langmuir模型,MB饱和吸附量(经UV/H2O2和UV/PS氧化1、2、4 h后分别记G1-1, G1-2, G1-3, G2-1, G2-2, G2-3)依次为580.26, 591.80, 598.63, 521.77, 554.91, 568.00 mg/g。研究表明,GO可以快速吸附较大浓度范围内的MB,且对低浓度染料表现出更好的去除效果;GO对MB的吸附量随着pH值的增加逐渐增大,且在碱性条件下的增加得更明显;经氧化处理后,GOs的吸附性能随着氧化时间的增长,性能减弱,尤其在UV/PS体系中更为显著。     

典型海域生境修复与生物资源养护研究进展与展望

海洋牧场建设是实现我国近海渔业资源恢复、生态系统和谐发展与蓝碳增汇的重要途径。近年来,在快速发展的同时也面临着诸多问题与挑战,极大制约了产业的健康发展。在海洋牧场建设过程中,关于生境营造和资源增殖的基础理论薄弱,对其生态系统稳定性与抗干扰能力认识不清,尤其对小尺度海洋牧场生态系统的结构及其功能实现过程,以及生态承载力知之甚少。亟需针对其人工鱼礁等生境营造的环境效应和增殖放流的资源补充效应开展理论印证和定量研究,以充分认识这些人为扰动的双重性。本文查阅了相关文献90余篇,简要回顾了国内外关于人工鱼礁生境营造的水动力环境特征、生源要素迁移过程、生物群落构建机制和局地生态系统稳定性评价等方面的研究进展。强调了小尺度海洋牧场生态系统结构的复杂性与动态性,重点关注了鱼礁群布局对牧场海域水动力环境、沉积物和生源要素演变的影响,以及在增殖放流等人为扰动下生物群落的物种共存机制。围绕海洋牧场生态系统稳定性与抗干扰能力等关键问题,从水动力驱动、生源要素表征、生物群落重建及生态系统健康等4个方面探讨了目前研究的不足与发展方向,以为海洋牧场人工鱼礁、海藻床等生境营造以及资源修复模式优化提供参考。