基于水声技术的黄海近海鱼类活动定点监测研究     

马燕芹  司纪锋 《渔业现代化》2016,(4):70-75

为了研究黄海近海鱼类活动规律,采用自主研制的科研型鱼探仪于2015年11月22日至12月5日对调查海域的鱼类活动进行了首次声学调查,统计分析鱼类活动规律。在调查海域布放4套鱼探仪设备对鱼类进行定点长时间监测,并将采集到的鱼类回波数据利用水声技术进行分析和处理,得到调查海域单体鱼类目标强度在垂直方向上的分布、鱼类目标强度大小的分布以及鱼类在不同水层和不同时间段的活动情况。结果显示,调查海域冬季鱼类主要活动在4~10 m的中上水层,鱼类分布随着水层深度的逐步增加而急剧减少;从9∶00至13∶00鱼类活动频度呈增大趋势,并在13∶00至14∶00频度达到顶峰(约为38%),随后频度减弱;统计得到该海域鱼类目标强度主要以-49~-40 d B占比最高,目标强度大于-40 d B的鱼类均匀分布在整个水层,目标强度小于-40 d B的鱼类主要分布在4~10 m浅水层。研究表明,采用水声技术能够实现对鱼类活动的监测;调查海域的鱼类目标强度分布比较集中,鱼类在深度上的分布主要集中于中上水层,鱼类在不同时间段的活动情况随水温变化而变化,温度升高鱼类活动频度增加,反之则降低。由此可知,该海域鱼类的种类以暖水物种为主。  相似文献   

乐清湾口海域春秋季鱼类群落多样性研究   总被引：1，自引：0，他引：1  

夏陆军  周青松  俞存根  宋伟华  郑基  毕耜瑶  谢旭  李德伟  叶深 《渔业现代化》2016,(2):68-75

为研究乐清湾口海域鱼类群落结构动态变化趋势和渔业资源现状,对该海域鱼类物种组成、种类数、多样性等群落结构特征进行调查分析。共鉴定出鱼类49种,隶属于10目26科39属。结果显示,春季物种数较秋季少,春季在瓯江口水域物种明显较少,秋季物种数空间分布大致为东西走向;春季种类重量多样性低于秋季,但尾数多样性高于秋季,鱼类种类数与多样性指数之间有较强的相关性。研究表明,乐清湾口海域的鱼类种类类型以近岸河口性鱼类为主,且大多为广温、广盐性种类;该海域位于河口,受瓯江径流影响较大;受地理位置和水文环境影响,该海域暖水性种类较多;种类数平面分布特征主要是春季受瓯江径流淡水水团影响,而秋季受交汇水团影响,物种丰富;两季鱼类多样性不同,是因为鱼类个体大小、数量随着季节的变化而变化。  相似文献   

水下LED集鱼灯灯载视频系统设计     

卢克祥  许家龙  王伟杰  钱卫国  叶超 《渔业现代化》2016,(6):51-54

为实时获取光诱捕捞作业时水下鱼群状态的视频信息,设计了一款水下LED集鱼灯灯载视频系统。该系统在结构设计上以水下LED集鱼灯为载体,在其内部嵌入了一套数字视频解决方案;在信号处理上利用正交频分复用技术(OFDM)对数字视频信号进行调制,以克服电力线上的杂波和电流信号固定脉冲对视频信号的干扰;在通信设计上以电力载波(PLC)方式作为视频信号传输方案。该系统设计完成后,对其信号传输性能进行了测试。结果表明,在电力线标称截面积6 mm2、长度30 m时,系统延时3 ms,丢包率0%,实际传输速率为8 000 Kbps。系统在不改变集鱼灯结构的前提下,添加了视频拍摄功能,且无需单独增设视频传输线,可作为光诱渔船上的辅助渔捞设备使用,也可拓展应用于鱼类行为实验中。  相似文献   

Sawfishes in The Gambia and Senegal – shifting baselines over 40 years          下载免费PDF全文

Ruth H. Leeney  Nigel Downing 《水产资源保护:海洋与淡水生态系统》2016,26(2):265-278

A review and meta‐analysis of growth and life‐history traits of a declining European freshwater fish,crucian carp Carassius carassius          下载免费PDF全文

Ali Serhan Tarkan  David Almeida  Michael J. Godard  Özcan Gaygusuz  Mark Rylands  Carl D. Sayer  Grzegorz Zięba  Gordon H. Copp 《水产资源保护:海洋与淡水生态系统》2016,26(1):212-224

Catching sharks: recreational saltwater angler behaviours and attitudes regarding shark encounters and conservation          下载免费PDF全文

Kate Mcclellan Press  John Mandelman  Elizabeth Burgess  Steven J. Cooke  Vivian M. Nguyen  Andy J. Danylchuk 《水产资源保护:海洋与淡水生态系统》2016,26(4):689-702

Effects of lysine and methionine supplementation on growth,body composition and digestive function of grass carp (Ctenopharyngodon idella) fed plant protein diets using high‐level canola meal          下载免费PDF全文

J. Jiang  D. Shi  X.‐Q. Zhou  L. Feng  Y. Liu  W.‐D. Jiang  P. Wu  L. Tang  Y. Wang  Y. Zhao 《Aquaculture Nutrition》2016,22(5):1126-1133

A 76‐day feeding trial was carried out to evaluate the effects of Lysine and Methionine supplementation on growth and digestive capacity of grass carp (Ctenopharyngodon idella) fed plant protein diets using high‐level canola meal (CM). Fish with initial average weight 103.9 ± 0.6 g were fed three extruded diets. Fish meal (FM) diet was formulated as the normal control with 40 g kg^?1 FM and 300 g kg^?1 CM; CM diet was prepared by replacing all FM with CM (total 340 g kg^?1) without Lys or Met supplementation; CM supplement (CMS) diet was similar to CM diet but was supplemented with essential amino acids (EAA) to ensure the levels of Lys and Met similar to those in the FM diet. Feed intake, feed efficiency and specific growth rate of the grass carp fed CMS and FM diets were similar (P > 0.05), but higher than those of the grass carp fed CM diet (P < 0.05). The hepatosomatic index, relative gut length, intestosomatic index and intestinal folds height were significantly improved in fish fed FM and CMS diets as compared to CM diet (P < 0.05). Lower activities of trypsin, lipase and amylase in hepatopancreas were observed in fish fed CM diet (P < 0.05). Three hundred and forty gram per kilogram CM without Lys or Met supplementation significantly decreased trypsin, lipase and amylase mRNA levels in hepatopancreas (P < 0.05). These results indicated that the high supply of CM (340 g kg^?1) in plant protein (200 g kg^?1 soybean meal and 100 g kg^?1 cottonseed meal) diets decreased digestive ability through decreasing digestive enzyme activities and enzyme gene's expressions of grass carp, and these side effects can be reversed by supplementing Lys and Met. Therefore, CM could be high level used in a plant protein blend‐based extruded diet for grass carp as long as EAA were supplemented.  相似文献   

Potential effect of increasing the water content in the digestibility of microdiets for fish larvae          下载免费PDF全文

M. Yúfera  J.A. Mata‐Sotres  C. Navarro‐Guillén  F.J. Moyano  G. Martínez‐Rodríguez 《Aquaculture Nutrition》2016,22(5):1116-1125

This study aimed to find a way for increasing the water content after rehydration of microdiet particles for fish larvae and to assess whether such increase contributes to a better disaggregation and digestion of particles within the gut of gilthead seabream larvae (4–15 days after hatching, dph). Four microdiets were prepared with increasing amounts of carboxymethylcellulose (CMC): 0, 20, 40 and 80 g kg^?1. The inclusion of CMC resulted in an effective increase of the hydration capacity of particles. Water content after immersion ranged from 800 g kg^?1 in the microdiet without CMC to 900 g kg^?1 with 80 g kg^?1 CMC. Larvae of different ages were fed during 10 h with these microdiets. The microparticles containing 80 g kg^?1 CMC were more degraded in the gut of the younger larvae. No clear differences were observed from 10 dph onwards. Differences in enzymatic activities were not evident except for α‐amylase in 6 dph larvae. Gene expression of the enzyme precursors did not show any relation to the water content of microdiets. Overall, the results indicate that increasing the water content up to 900 g kg^?1 may enhance the disintegration of food particles within the gut of younger larvae and to a lesser extent affect the response of digestive enzyme activities.  相似文献   

Osteological development and anomalies in larval stage of hatchery‐reared yellow catfish Pelteobagrus fulvidraco          下载免费PDF全文

Chao Huang  Xiao‐Ying Tan  Kun Wu  Qi‐Liang Chen  Mei‐Qin Zhuo  Ya‐Xiong Pan  Yu‐Feng Song 《Aquaculture Research》2016,47(4):1125-1140

Comprehensive knowledge of osteological development of fish not only provides means for understanding its functional development, but also allows early detection of skeletal anomalies. The present study was conducted to determine osteological development and occurrence of anomalies from the first to the 40th day after hatching (DAH) for yellow catfish Pelteobagrus fulvidraco, a commercially important species in China. Vertebral ontogeny started with formation of anterior neural arches at 3 DAH, and completed at 6 DAH. Vertebral centra started to develop at 4 DAH and ossification in all centra was visible at 15 DAH. Caudal fin appeared at 2 DAH and ossification was visible at 26 DAH. The onset of dorsal and anal fins appeared at 4 DAH and their ossifications were visible at 20 DAH. Pectoral fins were present before first feeding and formed entirely at 9 DAH, and their ossifications were visible at 21 DAH. Pelvic fins appeared at 9 DAH, and formed completely at 21 DAH. The ossification of pelvic fins was not finished until the end of the experiment (40 DAH). 24 types of skeletal anomalies were observed. About 20% of individuals showed at least one anomaly. Haemal vertebrae anomalies occurred at the highest frequency, followed by pre‐haemal, caudal vertebrae and anal fin anomalies, and caudal fin had the lowest anomalies frequency. For the first time, our study determined osteological development and anomalies incidence in larval yellow catfish, which help further investigations into rearing conditions leading to appearance of these anomalies to prevent their incidence.  相似文献   

Microbial communities in various waters used for fish larval rearing          下载免费PDF全文

Akito Taniguchi  Ryuichiro Aoki  Mitsuru Eguchi 《Aquaculture Research》2016,47(2):370-378

A major concern in larvae production is a mass mortality caused by fish diseases. In larvae production, pumped‐up natural seawater filtered through a sand filter system is used for fish rearing, and microalgae and rotifer cultures. Here, we investigated the community structures of eukaryotic microbes, as well as total bacteria and vibrios, in various processed ‘waters’ used in a larvae production site. We observed that ultraviolet irradiation of seawater was effective to reduce not only total bacteria and vibrios but also eukaryotic microbes. Moreover, the community structures of total bacteria and vibrios in rearing waters for fish larvae were different from those in rotifer cultures fed with Chlorella, but rather similar to those in natural seawater and microalgae cultures. These results suggest that the bacterial community in rearing waters may originate mainly from natural seawater and then be selected by microalgae in rearing water. Overall, this study provides useful information for avoiding the risk of fish disease outbreaks in a larvae production site.  相似文献