秘鲁沿岸秘鲁鳀渔场及渔汛分析

秘鲁鳀(Engraulis ringens)是栖息于东南太平洋沿岸的小型中上层鱼类,了解秘鲁鳀渔场和渔汛的状况有助于渔情预报工作的开展进而实现资源的合理利用。利用2005~2014年秘鲁各港口的上岸量数据,以上岸量(landings)、总捕捞努力量(fishing effort)和单位捕捞努力量渔获量(CPUE)为指标分析秘鲁鳀渔场分布及渔汛;结合二因素方差分析(two-factor analysis of variance)探究渔场月份和纬度上的显著性差异;利用分位数的方法,找出各年的旺汛时间。研究表明,每年的4~6月和11~12月为秘鲁鳀的主汛期;主要的捕捞区域分布在7°S~13°S;渔汛的前中期,上岸量和捕捞努力量有着明显的年间差异,而CPUE在渔汛后期年间差异明显。方差分析表明,不同月份和不同纬度对捕捞努力量[ln(effort+1)]有极显著的影响(P0.01);5月为一年中最主要的捕捞阶段。旺汛期分析表明,第一渔汛阶段的旺汛一般在5月出现,而第二渔汛阶段的旺汛一般在11月出现。研究结果有助于对秘鲁沿岸秘鲁鳀渔场及渔汛的认识。     

乳山近海渔业资源种类组成及变化

根据2013—2015年乳山近海拖网渔船的渔捞日志,分析了乳山近海的单位捕捞努力量渔获量、渔获种类组成及生物多样性等特征。结果表明:(1)乳山近海渔获物共有36种,隶属于19目28科33属。其中鱼类有26种,虾蟹类4种,头足类4种,水母类1种,贝类1种。(2)2013—2015年全年优势种差异明显。其中,蓝点马鲛3年均为优势种,鳀鱼是2014年和2015年优势种,网纹狮子鱼为2013年和2015年的优势种。(3)乳山近海渔获物主要集中在休渔期前后的4—5月、9—11月,渔业生产存在明显的春汛和秋汛。2013—2015年乳山近海单位捕捞努力量渔获量逐年增加,但与历史单位捕捞努力量渔获量相比还是存在明显下降;多样性指数和均匀度指数变化趋势一致,多样性指数和丰富度指数较高值出现在秋季;春汛和秋汛期间,渔业资源种属组成及群落结构相似性较高。     

Development of performance indices for the Newfoundland and Labrador snow crab (Chionoecetes opilio) fishery using data from a vessel monitoring system

This study investigates the potential for using data from a vessel monitoring system (VMS) to create indices of commercial fishery performance that may be used in monitoring snow crab resource status. Fishing hours were screened from hourly positional signals to create an index of fishing effort (hours fished) for comparison with that derived from logbooks (number of trap hauls). Similarly, a VMS-based fishing catch per unit of effort (CPUE) index was developed for comparison with CPUE derived from logbooks. Analysis of these indices showed that VMS-based fishing effort and CPUE indices can be interpreted to provide reliable complementary or alternative indices to logbooks for assessment of fishery performance in the Newfoundland and Labrador (NL) snow crab (Chionoecetes opilio) fishery. We also developed a VMS-based index of fishing efficiency and illustrate how it can be applied toward understanding various behaviors and anomalies in the fishery. VMS data may offer other potential applications for snow crab assessment and management. Our approach and methods are applicable to other commercial fishery resources worldwide that are monitored using vessel monitoring systems.     

What are the effects of climate on the offshore and onshore movements of adult grooved tiger prawns Penaeus semisulcatus in tropical northern Australia?

Historical catch per unit effort (CPUE) from the period in the development of commercial fisheries prior to the implementation of any temporal or spatial closures can provide insight into how environmental factors affect life history events. These insights can then inform contemporary fishery management practices to improve sustainability. We examined the timing of the offshore dispersal and onshore movement to aggregate on the spawning grounds of the grooved tiger prawn Penaeus semisulcatus in the north‐west Gulf of Carpentaria using all available historical CPUE data between 1970 and 1987. The impact of climate conditions on the timing of the winter minimum CPUE (dispersal) was quantified by fitting univariate relationships with non‐parametric weighted local regression (Loess). The timing of the winter minimum CPUE was delayed by 5 weeks in years with at least 1 week of rainfall > 250 mm, and was delayed by 5 weeks in years when the wet season continued through April, rather than ending in March. Under current climate predictions, rainfall is projected to increase in variability in this region. Our results indicate that the sustainability of the prawn trawl fishery may be enhanced if seasonal fishing effort restrictions and closure dates are not fixed, but are managed to reflect variation in the timing of the end of the previous wet season.     

Temperature conditions in the Argentine chub mackerel (Scomber japonicus) fishing ground: implications for fishery management

We describe the seasonal migrations of Argentine chub mackerel ( Scomber japonicus ) into the fishing ground in relation to sea surface temperature conditions and analyse the temperature evolution during the fishing season on the basis of 1955–97 time-series. The upper temperature limit for the presence of schools was around 19°C. At higher values, most schools leave coastal waters (< 50 m) for the shelf. An inverse relationship was observed between catches per unit of effort (CPUE) of the inshore fishery and sea surface temperature. The highest standardized CPUE values corresponded to temperatures lower than 19°C. Above this temperature, the probability of obtaining a standardized CPUE higher than 1 was extremely low, and the standard deviations were minimal. The economic benefit from catches was also analysed through the different months of the fishing season. It was found that the mean benefit corresponding to temperatures lower than 19°C exceeded approximately 15 times that obtained at higher temperatures. A simple fishing strategy was proposed to the commercial fleet in order to improve the economic benefit of the catches. The migratory pattern followed by mackerel during the spawning period was also analysed in relationship to other environmental factors like food availability. Zooplankton composition, size structure and abundance in coastal and shelf waters are described, and their implications for feeding ecology of larvae and adults of the species are discussed.     

中东大西洋中部海域中上层鱼类资源结构与渔场分布

为了解中东大西洋中部海域中上层鱼类资源结构与渔场分布,对2007-2014年入渔FAO34渔区3.11和1.32小区(毛里塔尼亚专属经济区)从事中上层鱼类捕捞的7艘国内渔船的生产数据进行了分析。结果表明,我国入渔船只数量、入渔渔船总产量和作业渔船平均日产量均呈现先增加、后减少的趋势,且在2011年入渔渔船总产量和作业渔船平均日产量到达最大值,2012年入渔船只数量到达最大值。渔获种类主要包括沙丁鱼(Sardina pilchardus)、短体小沙丁鱼(Sardinella maderensis)、金色小沙丁鱼(Sardinella aurita)、日本鲭(Scomber japonicus)和竹筴鱼(Trachurus trachurus),各渔获种类的渔获量年际间波动较为明显。月均产量在17.2~23.6 t/haul,最高值和最低值分别出现在12月和8月;月均总产量在1 279.0~2 414.2 t,最高值和最低值分别出现在1月和8月,12月至次年3月为渔汛旺期。渔场季节变化现象明显,夏秋季向北移动,冬春季向南移动,20.0°~20.8°N、17.4°~18.0°W区域为高产量海域。该海域中上层鱼类洄游现象明显,这可能主要与该海域的不同洋流在不同月份的强弱变化有关,该海域整体渔业资源呈现一定衰退现象。建议渔船入渔该海域从事中上层鱼类捕捞持谨慎态度,加强该海域渔业资源的研究与保护。     

Recruitment abundance index of Pacific bluefin tuna using fisheries data on juveniles

ABSTRACT:   The recruitment abundance index of Pacific bluefin tuna Thunnus orientalis was estimated from 1980 to 2003 fishing year by using the troll fishery data in Nagasaki Prefecture, western Japan. It has been shown that the troll fishery in Nagasaki Prefecture operates with good time–area coverage of the species habitat, and that the fishing power slightly changed during the period analyzed, based on fisheries statistics, published information, and interviews with the fishers. Average catch per unit effort (CPUEs) were standardized by a generalized linear model (GLM) considering the effects of fishing year, season and landing area. Standardized CPUE of age-0 bluefin tuna showed larger fluctuations year by year than the nominal CPUE combined for all ages. High CPUEs in fishing years of 1981, 1994, 1996 and 1999 were observed. Data from these years agreed with the higher recruitments estimated by virtual population analysis (VPA) or higher catch of age-0 fish reported for the Pacific side. The age-specific standardized CPUE of age-0 bluefin tuna in this study was judged to be a useful indicator of recruitment.     

A biophysical model to assess the trade‐off between larval recruitment and catch in southern Australia's largest prawn fishery

Data from stock assessment surveys, published research and climate sensors were linked to model the interaction between fishing, physical‐oceanographic processes and spatial patterns of larval settlement for western king prawn [Penaeus (Melicertus) latisulcatus]. This information was used to evaluate the trade‐off between larval recruitment and catch during fishing periods that demand high prices but coincide with spawning. Total rates of larval settlement were maximized when tidal currents and atmospheric physical‐forcing components were coupled with simulations of larval swimming behaviour under average gulf temperatures. Average gulf temperatures sustained longer larval durations and increased larval settlement rates by over 12% compared with warmer gulf conditions simulated under a scenario of global warming. Reproductive data coupled with outputs from the biophysical model identified consistent inter‐annual patterns in the areas contributing to larval settlement success. Areas located in the north‐east, and central‐west of the fishery, consistently contributed to over 40% of all larvae reaching a settlement in each year. Harvest sensitivity analyses indicated that changes in the spatial patterns of pre‐Christmas fishing could lead to improvements in overall rates of the larval settlement while maintaining or improving the levels of catch. Future studies to refine the model inputs relating to physical processes, larval behaviour and mortality rates for P. latisulcatus coupled with surveys of juvenile prawn abundance to ground truth the modelled predictions, would allow stock recruitment relationships to be more closely examined and inform adaptive management of the fishery in the future.     

南海南部拖网渔场开发现状分析

南海南部拖网渔场是我国拖网渔船在南海南部海域的最主要作业渔场，该渔场的开发为保证中越北部湾渔业合作协定顺利实施、拓展南海外海渔业生存空间、开发南海渔业资源及维护国家在南海的主权和海洋权益做出了巨大贡献。本文分析南海南部拖网渔场开发现状、存在问题、开发价值和潜力，探讨进一步推进渔场开发，加强我方对该渔场的有效管控的方法和途径。     

Quantifying the effects of bycatch reduction devices in Queensland''s (Australia) shallow water eastern king prawn (Penaeus plebejus) trawl fishery

This study presents results from an experimental 10-day research charter that was designed to quantify the effects of (a) a turtle excluder device (TED), (b) a radial escape section bycatch reduction device (BRD) and (c) both devices together, on bycatch and prawn catch rates in the Queensland shallow water eastern king prawn (Penaeus plebejus) trawl fishery. The bycatch was comprised of 250 taxa, mainly gurnards, whiting, lizard fish, flathead, dragonets, portunid crabs, turretfish and flounders. The observed mean catch rates of bycatch and marketable eastern king prawns from the standard trawl net (i.e., net with no TED or BRD) used during the charter were 11.06 kg/hectare (ha⁻¹) (S.E. 0.90) swept by the trawl gear and 0.94 kg ha⁻¹, respectively. For the range of depths sampled (20.1–90.7 m), bycatch rates declined significantly at a rate of 0.14 kg ha⁻¹ for every 1 m increase in depth, while prawn catch rates were unaffected. When both the TED and radial escape section BRD were used together, the bycatch rate declined by 24% compared to a standard net, but at a 20% reduction in marketable prawn catch rate. The largest reductions were achieved for stout whiting Sillago robusta (57% reduction) and yellowtail scad Trachurus novaezelandiae (32% reduction). Multidimensional scaling and analysis of similarities revealed that bycatch assemblages differed significantly between depths and latitude, but not between the different combinations of bycatch reduction devices. Despite the lowered prawn catch rates, the reduced bycatch rates are promising, particularly for S. robusta, which is targeted in another fishery. Prawn trawl operators are not permitted to retain S. robusta and the devices examined herein offer the potential to significantly reduce the incidental fishing mortality that this species experiences.     

对虾流网掉虾原因分析及其补救的技术措施

渤海、黄海北部秋汛捕捞对虾,以往主要使用拖网。为保护渔场水域的生态环境和幼鱼(幼体)资源,通过针对虾类行动的实验性观察,同时使用流网试捕。分析流网掉虾的原因和提出防范掉虾的技术措施,以便更好地实现“以流网代替拖网捕捞对虾”的技术改革。     

Reef fisheries in Porto Seguro, eastern Brazilian coast

Fish landings in Porto Seguro, in the eastern Brazilian coast, were monitored from September 1997 to August 1999 to describe the predominant species caught, the catch per unit effort (CPUE) and patterns of yields according to depth and season. A total of 223.5 t from 352 fishing trips made by a fleet of 53 boats was monitored. The fishery is conducted at depths from 20 to 150 m. The number of commercially valuable species caught was high (n=53). Snappers (Ocyurus chrysurus, Lutjanus analis and L. jocu) made up 38% of total catch. Pelagic species such as Coryphaena hippurus, Seriola dumerili, Thunnus albacares and T. atlanticus accounted for 43% while groupers, mainly Mycteroperca bonaci, represented 10%. Relative abundance of these target species was strongly dependent (P<0.001) upon depth and season. Higher yields of O. chrysurus (>20 kg/fisher per day) were observed between 20 and 40 m, from April to June. During spring–summer, yields of oceanic pelagic species increased rapidly, and catches of C. hippurus (40 kg/fisher per day) rose from November to January.     

基于GAM和权重分析的西北太平洋秋刀鱼渔情预报研究

为了提高秋刀鱼(Cololabis saira)渔情预报模型的时空分辨率, 提升生产经济效益, 本研究基于 2013─2016 年 7—11 月中国在西北太平洋公海的秋刀鱼生产数据及海洋环境数据, 利用广义可加模型(generalized additive models, GAM)分别拟合单位捕捞努力量渔获量(catch per unit effort, CPUE)的适宜性指数(suitability index, SI)与各海洋环境变量之间的 SI 模型, 结合提升回归树模型(boosting regression tree, BRT)进行权重分析, 建立以月份为周期的秋刀鱼栖息地适宜性指数(habitat suitability index, HSI)模型。结果表明, (1) GAM 能较好地拟合适宜性指数与环境变量的关系, 获得最优环境变量参数值;(2) 环境变量对 CPUE 影响权重的前 3 位分别为海表温度梯度、海表温度和混合层深度, 其中, 在秋季 9—11 月海表温度梯度的权重值均为最高;(3) HSI 模型的检验和评价总体准确率分别为 82.0%和 73.2%, 秋季可达 87.7%和 77.9%, 在盛渔期 10 月, 预测准确率达 89.4%;(4) HSI 高值区与秋刀鱼实际渔场在空间分布基本一致。研究表明该模型适用于秋刀鱼的渔情预报, 并在每天的速报中具有明显优势。     

Temporal dynamic and economic valuation of recreational fisheries of the lower Cuiabá River,Brazilian Pantanal

Fisheries are the most common ecosystem service that fish provide to human populations, yet recreational fisheries are often overlooked when evaluating such services. Here, the socioeconomic profiles of fishers, the composition of their catches and catch per unit effort (CPUE) are described, to estimate the economic value of the recreational fishery on a stretch of the Cuiabá River in the Brazilian Pantanal. Questionnaires were used to obtain socioeconomic information and fishing yield from fishers for 2013 and 2014. Additionally, a census on the number of fishers and fishing platforms along the sampled region was conducted in 2018. This recreational fishery mostly involves middle class adult males, based mostly in the Cuiabá city metropolitan region. They invested, on average, US$41.1 (SD = US$16.5, median = $35.2) per fishing visit, catching around 19 fish species. Overall, mean CPUE from the recreational fishery was 42.20 fish/fisher.day (17.4 kg/fisher/day). Annual economic value of this recreational fishery was estimated at around US$1.8 million, which highlights the importance of this activity to the local economy. Greater environmental conservation efforts are recommend to ensure the long-term viability of this ecosystem service.     

南极磷虾调查CPUE指数变动的影响因素初步分析

根据2010年1月~2月在南极南设得兰群岛和南奥克尼群岛周围水域开展的南极磷虾拖网调查期间收集的数据,对南极磷虾CPUE指数变动的影响因素(包括表温、水深、拖速和拖曳深度)进行了分析。结果表明:(1)开始捕捞至结束捕捞的表温相差较小时,平均CPUE相对较高(250 kg/min);(2)起放网表温在0.5~1.0℃和1.0~1.5℃时,平均CPUE均较高(250 kg/min);(3)当海底平均深度大于2 000 m时,CPUE均最低(100 kg/min);(4)随着拖速和拖曳深度的增加,平均CPUE逐渐减小,当拖速小于2.5 kn及拖曳水深小于25 m时,平均CPUE达到最大,分别为364.46 kg/min和347.59 kg/min。本研究结果可为开发南极磷虾资源提供基础数据,并为海上生产提供指导性参考。     

大眼金枪鱼渔场与环境关系的研究进展

大眼金枪鱼是金枪鱼远洋渔业的主要捕捞对象。本文从大眼金枪鱼适宜环境因子、大眼金枪鱼渔场变动、资源丰度及其与环境因子间关系的研究方法等几方面总结了大眼金枪鱼渔场与环境关系的研究进展。大眼金枪鱼种群资源丰度的指标主要是CPUE和标准化后的CPUE,CPUE标准化的方法主要是GLM模型和GLM/HBM模型;目前,分析大眼金枪鱼资源变化与环境间关系的研究方法主要有聚类分析法、G IS软件定性分析法和栖息地指数模型。其中,聚类分析适用于研究大眼金枪鱼的渔场变动,包括系统聚类分析法、动态聚类分析法和灰色星座分析法,利用G IS软件定性分析适用于分析单个环境因子对渔场产生的影响;而栖息地指数模型能综合多个环境因子,分析它们共同对渔场产生的影响。     

Standardizing catch and effort data of the Taiwanese distant-water longline fishery in the western and central Pacific Ocean for bigeye tuna, Thunnus obesus

Catch per unit effort (CPUE) is often used as an index of relative abundance in fisheries stock assessments. However, the trends in nominal CPUE can be influenced by many factors in addition to stock abundance, including the choice of fishing location and target species, and environmental conditions. Consequently, catch and effort data are usually ‘standardized’ to remove the impact of such factors. Standardized CPUE for bigeye tuna, Thunnus obesus, caught by the Taiwanese distant-water longline fishery in the western and central Pacific Ocean (WCPO) for 1964–2004 were derived using three alternative approaches (GLM, GAM and the delta approach), and sensitivity was explored to whether catch-rates of yellowfin tuna and albacore tuna are included in the analyses. Year, latitude, and the catch-rate of yellowfin explained the most of the deviance (32–49%, depending on model configuration) and were identified consistently among methods, while trends in standardized catch-rate differed spatially. However, the trends in standardized catch-rates by area were found to be relatively insensitive to the approach used for standardization, including whether the catch-rates of yellowfin and albacore were included in the analyses.     

Target strength measurements of suspended live ommastrephid squid, <Emphasis Type="Italic">Todarodes pacificus</Emphasis>, and its application in density estimations

ABSTRACT:   Average target strength (TS) measurements of free-swimming Todarodes pacificus are required for calculating abundance estimations using the echo integration method. In this study, 31 live T. pacificus (18.0–28.4 cm dorsal mantle length; [ML]) were suspended with mantle tilt angles horizontally similar to free-swimming orientation, and their TS were measured using a 38 kHz split-beam echo sounder. Normalized TS by squared ML of T. pacificus ML was calculated as −73.1 dB: TS = 20 log ML −73.1 dB. The density of T. pacificus at their fishing ground off the northern Sanriku coast, Japan, was then estimated first using the echo integration method with the obtained normalized TS measurements, and then using commercial purse seine fishery CPUE (catch (tons) of squid per haul of purse seine) data. The density of T. pacificus aggregations near the continental shelf edge and upper continental slope was estimated as approximately 50–400 individuals/100 m² using both the echo integration method and CPUE data, both density results were similar. It was considered feasible therefore, to assess T. pacificus biomass directly using the echo integration method.     

闽南、台湾浅滩渔场单拖渔业监测调查

本文根据2005年1~11月闽南、台湾浅滩渔场单拖渔业调查监测资料,分析和研究该海区单拖渔业利用状况、主要渔获物资源动态。结果表明:2005年渔获量平均密度指数(CPUE)3月最高,达134.41kg/h,随后迅速下降,9月为全年最低,仅34.75kg/h;渔获物组成以生命周期短、个体小、营养级较低的种类为主,二长棘鲷居绝对优势,占总渔获重量的38.8%;各主要种类渔业资源时空分布变化较为明显;近十年来,渔船功率和网具的日趋大型化,小型单拖渔船数量有所减少。通过监测调查为渔业管理部门制订科学的渔业资源养护措施、加强和完善渔业管理等提供科学依据。     

Spreading the economic risk: Harvesting strategies of multi-method inshore fisheries during drought in eastern Australia

Droughts are likely to increase in frequency and severity with climate change, modifying the economic viability of inshore fisheries in regions of hydrological extreme. Variation in the revenue and profit associated with different mixtures of fishing methods between non-drought and drought conditions was examined for commercial fishing businesses in three estuarine and coastal systems in eastern Australia from 1997 to 2007. Mean monthly revenue decreased from 8 to 36% between non-drought and drought. Decreased mean monthly revenue was primarily attributed to reduced revenue generation from ocean prawn trawling (≥20%) and estuarine prawn trawling (≥34%) during drought. Fishing method diversity (measured by a modified form of the Shannon index) and mean monthly revenue were positively related; however, mean monthly profit decreased between non-drought and drought under a range of alternative cost scenarios. Reduced mean monthly profit was primarily attributed to losses from ocean prawn trawling (≥15%) and estuarine prawn trawling (≥30%) during drought. Although diversified harvesting behaviour increased revenue generation, initial results indicated that this marginal economic benefit could have been compromised by the greater costs associated with the increased diversification which reduced overall profitability. Results of this analysis indicated that the commercial fishing sector is a drought-affected industry in New South Wales.