海州湾及邻近海域鱼类群落的营养功能群及其动态变化

根据2011年及2013―2016年春季和秋季在海州湾及邻近海域进行的渔业资源底拖网调查,对该海域鱼类群落营养功能群的组成及其季节和年间变化进行了研究。结果表明,海州湾及邻近海域鱼类群落可以划分为5个营养功能群,即虾食性、底栖动物食性、虾/鱼食性、浮游动物食性和鱼食性。整体来说,春季海州湾鱼类群落以底栖动物食性营养功能群为主,其中方氏云鳚(Enedriasfangi)在各年所占比例均较高;而秋季以虾食性营养功能群为主,小眼绿鳍鱼(Chelidonichthys kumu)为主要优势鱼种。从生物量组成角度分析,海州湾鱼类群落各营养功能群所占比例有明显差异,以虾食性和底栖动物食性的功能群为主,其次为虾/鱼食性,而浮游动物食性和鱼食性所占比例较小。方氏云鳚、小眼绿鳍鱼、长蛇鲻(Saurida elongata)、小黄鱼(Larimichthys polyactis)、狮子鱼(Liparis sp.)、玉筋鱼(Ammodytespersonatus)等6种鱼类为各营养功能群的主要优势种类。海州湾及邻近海域鱼类群落的营养功能群和优势种呈现出明显的季节和年间变化,海洋环境变化和鱼类的季节性洄游移动等是主要的影响因素。     

Assessment of commercial and recreational fishing effects on trophic interactions in the Cap Roux area (north‐western Mediterranean)

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Fish fauna in a Protected Greek lake: biodiversity, introduced fish species over a 80-year period and their impacts on the ecosystem

Abstract –  Lake Pamvotis is a tertiary natural shallow lake located in the NW of Greece. For biogeographical reasons, it historically contained only four fish species: two endemics ( Phoxinellus epiroticus , Squalius pamvoticus ), one native to the West Greece ( Barbus albanicus ) and the ubiquitous Anguilla anguilla . These species were almost exclusively present in the lake before 1920, forming remarkable commercially exploited populations. From the 1930s through the 1990s, 20 species were introduced into the lake for purposes of eutrophication control or to enhance the fishery. These introductions, some of them accidental have led to the apparent decline, even loss, of the native species. During the last three decades the fish fauna of the lake has shifted from the native, clear-water species to a predominance of introduced species, mainly those adapted for turbid eutrophic water ( Rutilus panosi , Cyprinus carpio and Carassius gibelio , and several Asian cyprinids). The current fish assemblage in the lake is dominated by introduced species particularly the Mosquitofish ( Gambusia affinis ) and the Lourogobios ( Economidichthys pygmaeus ) in the littoral zone, the benthopelagic allogynogenetic Prussian carp ( C. gibelio) , and the opportunistic Trichonis roach ( R. panosi ), in the pelagic zone.     

基于渔捞日志的海阳近海渔业资源种类组成及生物多样性分析

根据2013年在山东海阳近海海域生产的15艘渔船的渔捞日志,初步分析了该海域渔业资源的种类组成及生物多样性特征。全年共捕获渔业资源种类25种,隶属于14目、21科、25属,鱼类有16种,以暖温种和暖水种为主,虾蟹类4种,头足类2种,水母类2种,多毛类1种。优势种类主要为黄鮟鱇(Lophius litulon)、蓝点马鲛(Scomberomorus niphonius)及口虾蛄(Oratosquilla oratoria)、海蜇(Rhopilema esculentum)、三疣梭子蟹(Portunus trituberculatus)、日本蟳(Charybdis japonica)、中国明对虾(Fenneropenaeus chinensis)等。其中,口虾蛄为全年优势种。渔业资源群落多样性指数和丰富度指数春季最高,秋季次之,夏季最低,通过与山东近海历史调查数据对比可知,该海域渔业资源量大幅下降;均匀度指数(0.13~0.73)变化较小;海阳近海春季和秋季种属组成相似性较高。本研究可为海阳近海渔业资源管理和修复提供参考依据。     

Spatial and seasonal differences in the top predators of Easter Island: Essential data for implementing the new Rapa Nui multiple‐uses marine protected area

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A spatially explicit study of prey–predator interactions in larval fish: assessing the influence of food and predator abundance on larval growth and survival

We apply a coupled biophysical model to reconstruct the environmental history of larval radiated shanny in Conception Bay, Newfoundland. Data on the larvae, their prey and predators were collected during a 2‐week period. Our goal was to determine whether environmentally explicit information could be used to infer the characteristics of individual larvae that are most likely to survive. Backward drift reconstruction was used to assess the influence of variations in the feeding environment on changes in the growth rates of individual larvae. Forward drift projections were used to assess the impact of predators on mortality rates as well as the cumulative density distribution of growth rates in the population of larvae in different areas of the bay. There was relatively little influence of current feeding conditions on increment widths. Patterns of selective mortality indicate that fast‐growing individuals suffered higher mortality rates, suggesting they were growing into a predator's prey field. However, the mortality rates appeared to increase with decreasing predator abundance, based on the drift reconstructions. The relationship of growth and mortality with environmental conditions suggests that short‐term, small‐scale variations in environmental history may be difficult to describe accurately in this relatively small system (～1000 km²).     

Laboratory and field investigations on the effect of scheduled meal timings on growth performance and nutrient retention in an Indian major carp,Cirrhinus mrigala (Ham) fingerlings: Effect on nitrogen retention and excretion of metabolites

To investigate the effect of scheduled meal timings on growth performance in Cirrhinus mrigala fingerlings, two experiments were conducted. The first experiment was conducted under laboratory conditions and the fish were submitted to schedule meal timings (at 08:00, 12:00,16:00, 20:00, 00:00 and 04:00). A control on continuous feeding was also maintained. ANOVA had revealed a significant (p < .05) increase in live weight gain (g), growth per cent gain in body weight, specific growth rate, PER, GPR, GER and APD (%) values in fingerlings fed between 12:00 and 16:00 hours. A decline in growth parameters, nutrient retention and an increase in FCR values were observed in the group fed at 20:00, 00:00 hours and also in the control group. Studies have further revealed that meal timings had also significantly (p < .005) affected protein digestibility, nitrogen retention and excretion of metabolites . Fish carcass composition had significantly (p < .05) higher accumulation of protein (14.82 ± 0.032), fat (5.51 ± 0.006) and energy (5.95 ± 0.004) in the group fed at 16:00 hours. The second experiment was conducted under field conditions and the fish were submitted to schedule meal timings (at 08:00, 12:00, 16:00 and 20:00). A control on continuous feeding was also maintained. Significantly (p < .05) higher values in growth parameters were observed in the group fed at 16:00 hours and lower values in the group fed at 20:00 hours and also in controls. Water quality, nutrients and productivity status of ponds revealed favourable levels and appears to have been affected by meal timings. Thus, in C. mrigala, timings of food intake can serve to optimize the utilization of ingested calories.