Assessing fish quality status in transitional waters,within the European Water Framework Directive: Setting boundary classes and responding to anthropogenic pressures

Validation of the AZTI's Fish Index (AFI), proposed for the Basque Country (northern Spain), in assessing fish quality within the Water Framework Directive (WFD), is undertaken. The response to anthropogenic pressure is investigated, in setting the boundaries between the different quality status classes. Hence, 12 estuaries were sampled, at different frequencies, between 1989 and 2007, by means of a beam trawl. Significant (p < 0.0001) correlations were found between the AFI and oxygen saturation and ammonia. Oxygen quality standards are used to set boundaries between quality classes. Then, the AFIs obtained are compared with different anthropogenic pressures, including urban and industrial discharges, engineering works and dredging. The effects of the removal of some of these pressures are also studied. The total number of pressures within an estuary shows significant (p < 0.009) negative correlation with AFI, explaining between 51 and 62% of the variability in fish quality. The impact of pressures upon fish and demersal assemblages is detected as required by the WFD. Nonetheless, further investigation and intercalibration of the methods used, are necessary.     

基于氮稳定同位素的九龙江口鱼类营养级研究

采用氮稳定同位素技术对2013年6—8月九龙江口采集到的隶属于13目42科61属共71种鱼类的营养级进行研究。结果表明,九龙江口鱼类的δ15 N值跨度较大,介于7.23‰~14.66‰之间。以菲律宾蛤仔(Ruditapes philippinarum)为基准生物估算出鱼类的营养级介于1.70~3.89之间,营养级最低与最高的鱼类分别为少牙斑鲆(Pseudorhombus oligodon)与多鳞鱚(Sillago sihama)。与Fishbase同种鱼类的营养级数据进行比较,83.1%的鱼类的营养级均值处于Fishbase同种鱼类的营养级范围内,但81.7%的鱼类的营养级均值比Fishbase同种鱼类的营养级均值略低;与传统的胃含物分析结果比较,58.3%的鱼类的营养级在0.5个营养级的误差范围内。基于氮稳定同位素估算的鱼类营养级较低的原因可能与本研究样品中低龄鱼及幼鱼比例较大有关。与其他方法相比,稳定同位素法在研究体型较小的幼鱼和低龄鱼营养级更具优势。鱼类营养级随其个体大小的变化明显,但存在种的差异性:不同体长的髭缟鰕虎鱼(Tridentiger barbatus)和绿鳍鱼(Chelidonichthys kumu)的营养级跨度较大,分别为1.54和1.43;而鳓(Ilisha elongata)等的营养级则跨度较小,这可能与不同鱼类的食性变化有关。     

Paradigms for planktonic assemblages: 50 years of contributions from the Leigh Marine Laboratory,Northland, New Zealand

Abstract

Plankton includes the primary producers and consumers that are critical for healthy ecosystem function in the marine realm. My objective was to identify the major contributions of the Leigh Marine Laboratory to our broader understanding of planktonic assemblages. Significant contributions were made prior to 1990 on the ecology of larval fishes. From the 1990s the focus changed to the sensory biology of larval invertebrates and fishes, with a strong emphasis given to the role of reef sound in attracting potential settlers. Both early and post 1980s research has been highly influential in a paradigm shift away from passively drifting larvae that have little control over their fate. Important contributions have also been made on the dynamics of nutrient–phytoplankton interactions, larval development and aquaculture. Opportunities abound for future research on the dynamics of planktonic assemblages in shelf waters and in changing seas.     

Intertidal sand‐dwelling Peracarid fauna of Stewart Island

Abstract

The distributions of infaunal Peracarida (Crustacea) and their correlation with sediment type, tidal height, and degree of exposure were studied in winter (June) at five beaches on Stewart Island, New Zealand. The beaches were selected lo cover a range of exposures to wind and wave action and substrate sorting. Substrate and infauna samples were taken at four tidal levels from each, with a 0.0625 m² quadrat.

Sieve separation and statistical analysis of the substrate samples indicated predominantly sand‐sized particles from all beaches, with median diameters in the range +1.52 to +2.92 ? (phi) units. Substrates were well sorted throughout the size range: ? quartile deviation ranged from 0.26 to 0.71, skewness from —0.18 to +0.07 ?.

Peracarid fauna was generally abundant, with a maximum of 29 136 per m²sampled in a more sheltered beach. Cumacea was the most abundant group, followed by Amphipoda, Isopoda, and Tanaidacea; dominance followed a similar sequence, being 78%, 19%, 2% and 1% respectively. Frequency of occurrence at the 19 stations was headed by Amphipoda (100%), with Isopoda 53%, Cumacea 32% and Tanaidacea 11%.     

不同条件延缓未受精卵激活对鱼类细胞电融合的影响

泥鳅未受精卵先在合成卵巢液、郝氏液中分别浸泡15、20、30min,然后再受精孵化,统计发育情况,结果表明,合成卵巢液可有效延缓未受精卵遇水后被激活的时间,郝氏液对延缓未受精卵被激活也有一定作用,但效果比合成卵巢液差。用合成卵巢液配制不同浓度胰酶处理受体卵进行细胞电融合实验,胰酶质量浓度为5 mg/mL时,融合卵发育至囊胚期的比例比对照组(郝氏液)高2%,统计分析表明该差异是显著的(P<0.05);但发育至原肠期及孵出期的比例则与对照组无显著差异。胰酶质量浓度为2和1 mg/mL时,融合卵发育到各阶段的比例均低于对照组,统计分析表明两者的差异是显著的(P<0.05)。研究表明,溶液种类、胰酶浓度等对电融合卵的发育有明显的影响,但延缓受体卵的激活时间并不能提高电融合卵的出苗率。用郝氏液配制的2 mg/mL的胰酶溶液处理受体卵,可获得较高比例的融合鱼。     

Comparison of food compositon of clupeid fishes in the Bohai Sea

Analysis of stomach contents of samples of clupeid fishes (Japanese anchovy, half-fin anchovy, zunas' scaled sardine, rednosed glassnose and tapertail anchovy) collected from the catches of a 1982–1984 fishery resource survey showed they are zooplanktonivorous. Similar food groups, such as copepoda. Chaetognatha, Amphipoda and Mysidacea were found in the stomach. Dietary similarity coefficients were studied to evaluate the degree of similarity in the dietary species-pairs. Seasonal variation is discussed. Contribution No.2050 from the Institute of Oceanology, Academia Sinica.     

中国濒危淡水鱼类致危成因分析

中国１０００多种淡水鱼类因受水工建设、围湖造田、乱伐滥垦等改变和破坏水域环境、酷渔滥捕,水体污染,不合理引种,法制不全及执法不力等原因导致部分鱼类濒危。初步确定为９２种,分属９目,２４科,７８属,根据程度分为四个等级,绝灭４种,稀土２３种,濒危２８种,渐危３７种。     

8种石首鱼类线粒体基因组特征及分子系统进化分析

为探讨石首鱼科(Sciaenidae)鱼类分子系统进化关系,采用生物信息学方法分析了黑鳃梅童鱼(Collichthys niveatus)、棘头梅童鱼(C.lucidus)、大黄鱼(Larimichthys crocea)、小黄鱼(L.polyactis)、鮸鱼(Miichthys miiuy)、白姑鱼(Pennahia argentata)、黄姑鱼(Nibea albiflora)和皮氏叫姑鱼(Johnius belangerii)共8种石首鱼类线粒体基因组全序列的基本特征。结果显示,除皮氏叫姑鱼外,其余7种石首鱼类编码的37个基因排列顺序与脊椎动物线粒体基因组相同。基因组碱基分布存在不均衡现象,A+T含量高于G+C含量。线粒体基因组的基因变异位点分析结果表明,ND4和ND5基因可作为COI基因的辅助分子标记,应用于石首鱼类群体遗传学的研究中。黄鱼亚科5种鱼类13个蛋白质编码基因的Ka/Ks比值远低于1,显示出较强的纯化选择。皮氏叫姑鱼与其他石首鱼间的遗传距离均较大且亲缘关系较远,暗示叫姑鱼属或为石首鱼类中较为原始的类群。基于线粒体基因组全序列构建NJ系统树支持黄鱼亚科和白姑鱼亚科亲缘关系较近的形态学结论。而基于去除控制区后序列和13个蛋白质编码基因序列构建的系统树则表明两亚科鱼类间的差别在非编码区更为明显。     

2006～2007年福建沿岸海域石首鱼类资源量时空变化

基于2006～2007年福建沿岸海域4个航次的底拖网调查,分析了福建沿岸海域石首鱼科鱼类的资源现状.结果表明:4个航次共捕获石首鱼类16种,其中春季捕获石首鱼类10种,夏季和冬季均捕获14种,秋季捕获12种.不同航次捕获的石首鱼类占所有鱼类总渔获量的比例为10.43%～23.23%,平均15.71%.平均资源密度和平均个体密度分别为81.49 kg/km2和3 663.06 ind./km2.平均资源密度和平均个体密度均以秋季最高,分别为130.02 kg/km2和5 702.64 ind./km2.闽东沿岸海域、闽江口及其附近海域、闽中沿岸海域和厦门沿岸海域石首鱼类的全年平均资源密度分别为70.75、96.23、22.54和84.57 kg/km2.在各种石首鱼类中,叫姑鱼(Johnius belengerii)的资源密度和个体密度最大,其次是丁氏(Wak tingi).叫姑鱼的相对重要性指数最高,为871.01,仅叫姑鱼为优势种.与近20 a前的调查资料相比较,石首鱼类的渔获量占鱼类总渔获量的比例升高,但资源密度显著下降,必须采取措施,避免开发强度的继续增加,以利于其资源的可持续利用.