Performance of Mixed Species and Mono‐specific Algal Diets for Culture of Larval Western School Prawns,Metapenaeus dalli

The effect of three mono‐specific and four combinations of the diatoms Chaetoceros muelleri, Chaetoceros calcitrans, and the chlorophyte Tetraselmis suecica on survival, development, and dry weight of the western school prawn, Metapenaeus dalli, was assessed from protozoea I until mysis I. The development and dry weight of larvae were significantly greater when fed diets comprising C. muelleri and/or T. suecica. A fourth diet, consisting of all three microalgal species also performed just as well. Survival alone was a poor measure of the performance of the various diets. Larvae fed with C. calcitrans, either alone or in a mixed diet with either C. muelleri or T. suecica, had significantly slower development and lower dry weight. Overall performance, assessed using the normalized biomass development index, determined that both mono‐specific and mixed diets containing C. muelleri and T. suecica were among the best for M. dalli larvae. These results for M. dalli are consistent with those found for commercially grown penaeid prawns. This study enhances the limited knowledge on the feeding requirements of metapenaeid prawn larvae. Moreover, the results will help improve hatchery methods for the aquaculture‐based enhancement of M. dalli in the Swan‐Canning Estuary and potentially increase the abundance of this iconic recreational species.     

应用浮游植物生物完整性指数评价长江上游河流健康

2013年11月-2014年6月对长江上游宜宾至江津段五个断面的浮游植物进行了四次调查,共鉴定出浮游植物6门38属95种。对13个备选指标进行分布范围、判别能力及Pearson相关性分析,构建了适合长江上游的浮游植物生物完整性指数(P-IBI)指标体系,即香农多样性指数、Margalef丰富度指数、Pielou均匀度指数、浮游植物密度、硅藻密度百分比等参数指标。采用3分制法、4分制法和比值法分别对生物指标计分,评价结果显示:高庄桥、羊石处于"健康"状态;白沙处于"亚健康"状态;而江安、德感处于"亚健康"向"一般"过渡状态。综合来看,三种评价方法所反映各样点的健康状况基本一致,只是4分制法和比值法在划分评价等级上更细致,评价结果更精确。Pearson相关性分析显示:TN、pH与P-IBI值呈显著负相关(P0.05)。     

绍兴市凡纳滨对虾围垦滩涂养殖池塘的理化环境和浮游植物

2016年和2017年分别调查了位于浙江省绍兴市滨海新区的12口凡纳滨对虾围垦滩涂养殖池塘内的理化环境和浮游植物。结果显示:池塘内盐度变化范围为0~2,溶氧为6.2~13.9 mg/L,pH为7.5~9.8,总氨氮(TAN)为0.00~0.72 mg/L,亚硝酸盐氮(NO_2~--N)为0.00~1.70 mg/L,硝酸盐氮(NO_3~--N)为0.18~4.77 mg/L,总氮为1.74~6.08 mg/L,总磷为0.20~2.72 mg/L,总有机碳为1.88~42.57 mg/L,C/N为10~39。池塘内浮游植物种类隶属6门、24科、42属,其中蓝藻和绿藻为优势种。浮游植物生物量为(0.15~2.30)×107cell/L,叶绿素a(Chl.a)为2.62~37.24μg/L。Chl.a与蓝藻生物量显著正相关。NO_2~--N和NO3--N均与pH显著负相关。初步分析认为高pH可能是导致2016年池塘养殖凡纳滨对虾死亡率较高的重要原因,因此采取措施控制蓝藻生物量和水体的p H应有助于提高对虾养殖的存活率。     

Toward an environmental predictor of tuna recruitment

Bigeye tuna are of global economic importance and are the primary target species of Hawaii's most valuable commercial fishery. Due to their high commercial value, bigeye tuna are relatively well studied and routinely assessed. Larval and adult bigeye surveys have been conducted for many years and are supported by ongoing research on their physiology and life history. Yet, modeling stock dynamics and estimating future catch rates remain challenging. Here, we show that an appropriately lagged measure of phytoplankton size is a robust predictor of catch rates in Hawaii's bigeye tuna fishery with a forecast window of four years. We present a fishery‐independent tool with the potential to improve stock assessments, aid dynamic fisheries management, and allow Hawaii's commercial longline fishing industry to better plan for the future.     

渤海湾外来浮游植物物种及其入侵途径分析

为了预防外来浮游植物入侵引发的渤海湾赤潮灾害，基于近20年建设项目环境影响评价报告书和相关文献资料的研究成果，收集整理了渤海湾海域已发现的外来浮游植物物种及具体物种信息，分析了物种入侵的主要途径及可能产生的赤潮灾害影响。结果表明：渤海湾海域共发现17种外来浮游植物，其中，甲藻门最多，有10种；硅藻门次之，有5种；金藻门和黄藻门最少，各有1种。研究表明：渤海湾外来浮游植物中，除中华盒形藻外，其余16种均属于赤潮生物，这些物种主要通过压载水引入、传播的方式进入渤海湾海域，应加强港口监控和管理，以防赤潮灾害。     

松花江哈尔滨段夏季浮游植物群落结构与环境影响评价

2008年8月，对松花江哈尔滨段浮游植物群落结构进行研究，同时对水域环境影响作出评价。结果显示：松花江哈尔滨段夏季共有浮游植物7门43属72种，含5个变种。种群结构以绿藻门、硅藻门和蓝藻门为主。优势种以蓝藻门、绿藻门及硅藻门的小环藻为主。基于优势种、丰度、生物量、污染指示群落和理化指标综合评价，松花江哈尔滨段夏季呈富营...     

2006-2010年夏季青海湖浮游植物研究

2006-2010年夏季对青海湖14个采样点浮游植物的种类组成和生物量进行了调查.共发现浮游植物5门29属34种,其中硅藻门14属18种,蓝藻门4属4种,绿藻门8属8种,裸藻门2属2种,甲藻门1属1种.硅藻门是种类组成上最重要的类群.斯潘塞布纹藻Gyrosigma spenceri、尖布纹藻G.acuminatum、梅...     

浮游动物在生物操纵法除藻中的作用研究

采用室外现场实验和室内受控生态系统实验相结合的方法,研究了富营养化水体中浮游动物对藻类生长的控制作用。对浮游动物与藻类的计数与测量数据,利用SPSS统计软件进行了方差分析（LSD多重比较法）和相关性分析。实验结果显示,总磷含量比总氮含量对浮游动物生长的影响更大。浮游动物与藻类之间呈现显著或极显著相关关系,说明浮游动物群体,尤其甲壳类群体,在适当条件下对藻类群体以及其中的蓝藻有一定的控制作用。适当的鱼类密度下,浮游动物能够起有效的控藻作用,但鱼类密度过高会抑制该作用。底泥在生态系统中起重要作用,能够影响浮游动物对藻类的摄食力。     

Responses of phyto- and zooplankton to liming in a small acidified humic lake

Liming resulted in an immediate and transitory decrease of plankton biomass and phytoplankton primary production in the limed part of an acidified humic lake. In the longer term liming has changed species composition and dominance of phyto- and zooplankton. Due to increased transparency and improved oxygen conditions plankton biomass peaked deeper in the water column after liming. During the three years post-liming period phyto- and zooplankton communities have changed less than reported in several other studies. This is largely because liming was carried out well before the collapse of perch population, which has controlled zooplankton both in the pre- and post-treatment period.     

Threadfin shad impacts phytoplankton and zooplankton community structures in channel catfish ponds

Plankton community structure and chlorophyll a concentration were compared in twelve 0.1 ha earthen ponds co‐stocked with channel catfish (Ictalurus punctatus Rafinesque, 1818) in a multiple‐batch culture (initial biomass=5458 kg ha^?1) and a planktivore, threadfin shad (Dorosoma petenense Güther, 1867; initial biomass=449 kg ha^?1), during the April–November growing season. We used a completely randomized design in a 2 × 2 factorial arrangement to test the planktivore level (presence or absence of threadfin shad) and channel catfish feeding frequency (daily or every third day). Channel catfish were fed a 32% protein feed to apparent satiation on days fed. The presence of threadfin shad affected phytoplankton and zooplankton community structure more than did feeding frequency, and the impact in ponds was more pronounced after 1 July. The numbers of all major groups of zooplankton were lower in ponds with threadfin shad, but were unaffected by the feeding frequency. Chlorophyll a concentration before 1 July was higher in ponds with threadfin shad and unaffected by the feeding frequency, whereas after 1 July it was higher in ponds without threadfin shad and that were fed daily. Phytoplankton community structure after 1 July was dominated by nuisance algal bloom genera of cyanobacteria in ponds without threadfin shad and by Bacillariophyceae in ponds with threadfin shad.