以数值实验为基础的米字型鱼礁布设模式差异下的流场效率

人工鱼礁投放规模是鱼礁建设的核心问题之一,其中礁体数量与布设间距不仅表征了鱼礁规模的范围和密度,而且也决定着人工鱼礁流场效率。本研究采用数值实验方法,对典型结构边长为l的米字型人工鱼礁在4种投放量(2×2、3×3、4×4和5×5)、7种布设间距(0 l、0.5 l、1.0 l、1.5 l、2.0 l、3.0 l和4.0 l)下的流场相对体积、相对高度、相对长度等流场效率特性进行比较分析。结果显示,当上升流目标流速比分别为小于0.10、0.10～0.15和大于0.15倍时,上升流流场存在协同效应的最大布设间距分别为4.0 l、3.0 l、2.0 l,背涡流目标速度比下最大间距均为3.0 l;人工鱼礁投放量越多,上升流与背涡流相对体积越大,平均相对体积增长率越低,0.5 l布设间距的上升流相对体积与鱼礁单体相对流场体积最大,1.5 l布设间距的背涡流相对体积与鱼礁单体相对流场体积最大;上升流相对高度随投放量增加以1.01倍速率增加,随布设间距增加以0.90倍速率降低,背涡流相对长度随布设间距的增加先增后降,相对长度最大值位于1.0 l处。     

Movement patterns of gray triggerfish,Balistes capriscus,around artificial reefs in the northern Gulf of Mexico

Little is known about the movement patterns of gray triggerfish, Balistes capriscus Gmelin, in the northern Gulf of Mexico. To examine fine‐scale movements, gray triggerfish (n = 17) were tagged with transmitters and tracked with the VR2W Positioning System from 17 October 2012 to 9 December 2013. Most (76%) tagged fish survived and were tracked for 1–57 weeks. Tagged fish showed significantly larger home ranges and core areas in autumn than winter–spring and during day than night. Seasonal movement patterns were positively correlated with water temperature. Gray triggerfish stayed close to the reef (mean ± SD distance = 35.9 ± 28.4 m) and showed high site fidelity (64%) and high residency (>57 weeks). These patterns emphasise the importance of structured habitat for this species and suggest that artificial reef building in the northern Gulf of Mexico has enhanced this population.     

Biogeographical and ecological context for managing threats to coral and rocky reef communities in the Lord Howe Island Marine Park,south‐western Pacific

• 1. Quantitative subtidal surveys of fishes, macro‐invertebrates and sessile organisms at 33 sites within the Lord Howe Island Marine Park revealed a rich fauna and flora, including 164 fishes, 40 mobile invertebrate taxa, 53 coral and other sessile invertebrate taxa, 32 algal taxa, and two seagrasses. The biota in this newly‐zoned marine park was overwhelmingly tropical when species lists were tabulated; however, species with distributions centred on temperate coasts of eastern Australia and New Zealand occurred in disproportionately high densities compared with the tropical species.
• 2. Lord Howe Island reefs were generally in good condition. Virtually no bleached coral was observed (0.2% of the reef surface; 0.8% of total hard coral cover). Living scleractinian coral comprised the predominant group of organisms growing on reef surfaces, with 25.5% cover overall. Other major taxa observed were brown algae (18.8% cover) and red algae (16.9% cover).
• 3. Three distinctive community types were identified within the marine park—coral reefs, macroalgal beds and an offshore/open coast community. The distribution of these community types was strongly related to wave exposure, as indicated by an extremely high correlation with the first principal coordinates axis for biotic data (R²=0.80).
• 4. The close (<3 km) proximity of tropical coral and temperate macroalgal community types off Lord Howe Island is highly unusual, with localized patterns of nutrient enrichment suggested as the primary cause. The macroalgal community type is only known from a small area off the south‐western coast that is not protected from fishing. This community is considered highly susceptible to threats because of potential impacts of global warming and the possibility of expansion of sea urchin barrens. Coral bleaching and ocean acidification associated with global climate change also threaten the coral reef community, which includes relatively high numbers of endemic and near endemic fish species. Copyright © 2009 John Wiley & Sons, Ltd.

     

The Value of a Net‐Cage as a Fish Aggregating Device in Southern California

There is an urgent need for primary data that can be used to quantify the value of marine aquaculture facilities that also describe influences on the surrounding natural ecosystem and its wild fish communities. Divers completed 360 transect replicates below a net‐cage and at nearby and distant rocky reefs off Catalina Island, California, estimating the species abundance and size class of all conspicuous fishes in the water column. We observed 10,234 fishes aggregating below the net‐cage with a mean annual density of 142 (SE ± 30) per 100 m² and diversity H′ 2.29. At the adjacent reference reef, we counted 8452 fishes with a mean annual density of 117 (SE ± 20) and H′ 1.45 and at Reference Reef 2, located 500 m away, there were 8958 fishes with a density of 124 (SE ± 20) and H′ 1.13. The total density of fishes was the same between the study sites (ANOVA; P = 0.24); however, the spatial density of fishes in the water column was different between the net‐cage and reference reefs. Additionally, the density of juvenile fish was significantly lower at the net‐cage (ANOVA; P = 0.02), while the density of subadult and adult fishes was higher (ANOVA; P = 0.03). Feeding guild analysis ranked the net‐cage highest (3507), while Reference Reef 1 (2149), and Reference Reef 2 (2241), had lower values, a relationship often found between artificial and natural reefs. This suggests the importance of available trophic resources to the adult population of wild fishes, and has implications in the artificial reef attraction–production debate. The results of this study not only reproduce a pattern of fish attraction to net‐cages in the marine environment reported in previous studies but also demonstrate a relative habitat value compared in both time and space, of the fish community at a net‐cage compared with vibrant kelp bed communities.     

Multicriteria estimate of coral reef fishery sustainability

A holistic basis for achieving ecosystem‐based management is needed to counter the continuing degradation of coral reefs. The high variation in recovery rates of fish, corresponding to fisheries yields, and the ecological complexity of coral reefs have challenged efforts to estimate fisheries sustainability. Yet, estimating stable yields can be determined when biomass, recovery, changes in per area yields and ecological change are evaluated together. Long‐term rates of change in yields and fishable biomass‐yield ratios have been the key missing variables for most coral reef assessments. Calibrating a fishery yield model using independently collected fishable biomass and recovery data produced large confidence intervals driven by high variability in biomass recovery rates that precluded accurate or universal yields for coral reefs. To test the model's predictions, I present changes in Kenyan reef fisheries for >20 years. Here, exceeding yields above 6 tonnes km^?2 year^?1 when fishable biomass was ~20 tonnes/km² (~20% of unfished biomass) resulted in a >2.4% annual decline. Therefore, rates of decline fit the mean settings well and model predictions may therefore be used as a benchmark in reefs with mean recovery rates (i.e. r = 0.20–0.25). The mean model settings indicate a maximum sustained yield (MSY) of ~6 tonnes km^?2 year^?1 when fishable biomass was ~50 tonnes/km². Variable reported recovery rates indicate that high sustainable yields will depend greatly on maintaining these rates, which can be reduced if productivity declines and management of stocks and functional diversity are ineffective. A number of ecological state‐yield trade‐off occurs as abrupt ecological changes prior to biomass levels that produce MSY.     

Shelf‐edge reefs as priority areas for conservation of reef fish diversity in the tropical Atlantic

• 1. Data from fishing surveys employing bottom long‐lines were analysed to characterize the diversity, assemblages and distribution patterns of demersal fish along the Brazilian outer shelf and upper slope, between latitudes 13°S and 22°S.
• 2. Non‐metric multi‐dimensional scaling (MDS) and cluster analysis indicate three distinct species assemblages separated primarily by depth (the 200 m isobath) and secondarily by latitude (19°S), suggesting a continual transition along the depth and latitudinal gradients in the study area. Species richness was negatively correlated with depth, but with no clear relationship with latitude.
• 3. Results suggest the existence of reef formations on the shelf‐edge zone (40–200 m) and slope down to 500 m depth off the eastern Brazilian coast. More than 75% of the catches recorded were reef fish species from the families Serranidae, Lutjanidae, Malacanthidae, Muraenidae, Sparidae, Balistidae, Carangidae, Haemulidae, Scorpaenidae and Priacanthidae.
• 4. The maximum depth of occurrence for 20 reef species was extended from limits previously recorded.
• 5. The findings reinforce the hypothesis of a faunal corridor for species associated with deep reef formations along the shelf‐edge zone (40–200 m), in the South American continental margin, connecting the south‐western Atlantic and the Caribbean provinces.
• 6. The shelf‐edge reefs support important multi‐species fisheries and harbour critical habitats for the life cycle of many reef fish species, including spawning aggregation sites that are extremely vulnerable to human pressures, such as intensive fishing, shipping and offshore oil and gas exploitation; all activities currently expanding off the Brazilian coast.
• 7. Results reveal the biological importance of deep shelf‐edge reefs as a critical ecological area. Despite their importance, shelf edge reefs are not currently included in any marine protected area network in the tropical south‐western Atlantic. There is now an urgent need to enhance knowledge, implement adequate management strategies and consider these deeper habitats as priority areas for conservation. Copyright © 2011 John Wiley & Sons, Ltd.

     

Habitat use patterns of newly settled spotted seatrout in estuaries of the north‐western Gulf of Mexico

Abstract This study examined habitat use patterns of newly settled spotted seatrout Cynoscion nebulosus (Cuvier) across several Gulf of Mexico estuaries. Intensive sampling using an epibenthic sled was conducted in three Texas bays and among three potential habitat types. A long‐term data set (1982 to 1997) from the National Marine Fisheries Service was also used to examine C. nebulosus habitat use patterns in both marsh and seagrass‐dominated bay systems for broad regional comparisons along the north‐western Gulf of Mexico. Vegetated habitat types such as seagrass and marsh supported the highest densities and use was dependent upon availability of particular vegetated habitat types. In laboratory mesocosm experiments, both wild‐caught and hatchery‐reared C. nebulosus, showed strong selection for structured and vegetated habitat types. These field and laboratory results suggest that seagrass meadows and marshes may be functioning as important habitat for C. nebulosus in Gulf of Mexico, and other habitat types such as oyster reef need further evaluation.     

人工鱼礁对防城港海域小型岩礁性鱼类诱集效果研究

为探究人工鱼礁聚鱼效果,于 2017 年 2 月、4 月、9 月和 11 月主要通过声学探测技术,对防城港海域渔业资源密度、空间分布与大小组成进行了调查研究。结果显示,防城港人工鱼礁区及其临近海域 4 次调查共捕获各类游泳生物和底栖无脊椎动物 201 种,包括鱼类 126 种、蟹类 32 种、虾类 20 种、虾蛄类 11 种和头足类 12 种。双因素方差分析结果表明,调查海域渔业资源密度在时空层面上均存在显著性差异(P<0.001),且交互作用显著(P<0.001)。2 月调查海域人工鱼礁区渔业资源密度(547745 ind/n mile2)约为其周边海域(203990 ind/n mile2)的 2.68倍,表现出明显的聚鱼效果。其中,二长棘鲷(Parargyrops edita)、多齿蛇鲻(Saurida tumbil)、花斑蛇鲻(Sauridaundosquamis)等岩礁性底层鱼类为该季度主要优势种类。各航次人工鱼礁区小型个体所占比重较高,其平均目标强度(TS)分别为 55.6 dB(2 月)、 54.5 dB(4 月)、 53.6 dB(9 月)和 52.2 dB(11 月),随个体生长其平均 TS 呈稳步增大的变化趋势。在垂直方向上, 2 月和 4 月航次人工鱼礁区 90%以上回波单体主要分布在 9~16 m 中下水层。上述研究结果表明,人工鱼礁建设对防城港海域小型岩礁性鱼类表现出明显的向底层诱集的效果,该结果能为海洋牧场生态效应系统评价提供重要支撑。     

布设间距对多孔方型人工鱼礁流场效应影响的数值模拟研究

采用计算流体动力学(CFD)技术,研究了不同布设间距下,多孔方型人工鱼礁周围水流运动的规律,旨在为深入研究人工鱼礁的集鱼原理和海洋牧场建设中人工鱼礁的投放和布设提供更多参考。本研究采用了4种布设间距,分别为0.5、1、1.5和2倍鱼礁高度,基于计算机数值模拟技术,模拟了速度为0.8m/s的水流流经2个礁体的过程,分别观察鱼礁周围水流运动情况。结果显示,多孔方型人工鱼礁内部和周围存在缓流区、背涡流区、上升流区、死水区等有显著特征的区域;多孔方型人工鱼礁上升流的最大速度与来流速度的比值约为0.95倍;多孔方型人工鱼礁周围上升流最大抬升高度与鱼礁高度之比约为2.1;多孔方型人工鱼礁的结构在一定程度上为鱼礁周围的流态多样性提供了较有利的作用;多孔方型人工鱼礁的布设间距对2个鱼礁单体间的旋涡数量和旋涡方向有较大影响,也对涡量大小和涡量分布范围产生影响。研究表明,在一定范围内,布设间距越大,涡量越大,分布范围越广,但超过一定范围后,涡量不再增大,分布范围也不再扩大;多孔方型人工鱼礁的布设间距越大,背涡流在X方向和Y方向的影响面积越大。研究结果清晰地展现了不同布设间距下的人工鱼礁的流场效应,对在特定条件下进行人工鱼礁投放和布设具有重要意义。     

海州湾人工鱼礁养护资源效果初探

20 0 3年 7月至 2 0 0 3年 12月在连云港海州湾投放了第一批人工鱼礁 ,2 5 0个单体大礁 ,75 0个小礁体 ,30只船礁 ,共计 135 30m3 (空方 )。为了探讨海州湾人工鱼礁投放后鱼礁区的渔业资源养护情况 ,对该海区进行 6个航次的调查 ,投礁前调查 3次 ,投礁后调查 3次。调查结果表明 :人工鱼礁投放后鱼礁区生物多样性指数和丰度均有所增加 ;鱼礁区CPUE比投礁前增加 1倍左右 ,其中鱼类的CPUE增加最多。鱼礁区比对照区相对应时期的CPUE要高许多 ;优势资源种类也有一定的变化。     

大亚湾杨梅坑人工鱼礁水域生物资源量声学评估

杨梅坑人工鱼礁区位于深圳市东部大亚湾海域,2007年3月20日开始投礁,12月25日正式完成全部工程施工任务,建礁体积9.51万km3,礁区面积966 m×2 851 m.从2007年4月到2009年5月,使用科学鱼探仪(EY60型,120 kHz,Simrad)先后在不同季节对大亚湾杨梅坑生态调控区的礁区内和礁区外水域进行了6次声学调查,共获取有效声学航程122.54 n mile,以了解建礁后该水域生物分布和资源量密度变化情况.调查中设站点进行生物学拖网采样以辅助声学评估.利用Echoview声学处理软件对数据进行分析处理,结合历史资料记载的生态、资源特点以及本研究中拖网生物学数据,以0.5 n mile为间隔输出积分值,并对该海域的生物资源量密度和生物资源量进行评估.声学评估结果表明,第1航次春季调查礁区内和礁区外的平均生物资源量密度分别为41×103 kg/n mile2和28×103kg/n mile2,第3航次春季调查礁区内和礁区外的平均生物资源量密度分别为16×103 kg/nmile2和10×103 kg/n mile2,第4航次夏季调查礁区内和礁区外的平均生物资源量密度分别为65×103 kg/n mile2和3×103 kg/n mile2,第5航次秋季调查礁区内和礁区外水域的平均生物资源量密度分别为165×103 kg/n mile2和45×103 kg/n mile2.结果表明,礁区内水域的平均生物资源量密度高于礁区外水域,并且随着建礁时间的推移,礁区内水域的生物资源总量基本呈增长趋势,同时礁区内的声学评估种类也明显增加.根据拖网生物学数据,建礁后优势种中的优质经济鱼类种数增加明显,如黄斑蓝子鱼和日本金线鱼等,说明人工鱼礁的建设有效地改良了渔业资源结构.     

Spawning of red snapper (Lutjanus campechanus) in captivity

Red snapper (Lutjanus campechanus) spawned in captivity when held at temperatures and photoperiods which approximated normal conditions in the Texas Gulf of Mexico region. Multiple spawns were observed in May and June, 1978.     

基于单位鱼礁规模的米字型人工鱼礁流场效应定量研究

流场效应是人工鱼礁发挥其生态效应的基础,流场效应强弱受单位鱼礁规模影响,同时是衡量人工鱼礁建设模式优劣与规划人工鱼礁建设模式的重要参考因素,流场体积是表征流场效应强弱的重要指标。本研究基于数值实验方法,分析米字型人工鱼礁在4种布设模式下28种单位鱼礁规模的流场体积变化规律,并建立上升流、背涡流流场体积与人工鱼礁建设规模指标的多元非线性模型。结果表明,单位鱼礁建设一级指标投放量(T_a)、布设间距(L_d)及目标速度比(R_u)与上升流体积分别呈线性、三次函数及幂函数关系,建立上升流体积回归模型为V_u=T_a×(0.002L_r~2-0.055L_r-2.429V_R×R_u+0.011R_u~(-1.833)+0.227L_d+0.437),回归拟合R~2为0.957,相对误差为18.61%。与背涡流体积分别呈幂函数、三次函数及指数函数关系;结合单位鱼礁建设二级指标相对边长(L_r)、容积率(V_R),背涡流体积回归模型为V_b=R_u×(-0.543L_r~2+2.388L_r)–51.779V_R~2+75.045V_R+1.449×10~(-4)T_a×e~(12.049 Ru)+1.620L_d×T_a,回归拟合R~2为0.938,相对误差为10.09%。该流场体积回归模型可用于规划指导均匀布设模式的人工鱼礁建设,为"减量增质提效"的人工鱼礁建设策略提供参考。     

黄鳍棘鲷幼鱼对不同开孔形状和直径的人工鱼礁模型的行为响应

为了分析岩礁性鱼类在不同开孔形状及不同开孔大小下的趋礁行为及空间分布,以黄鳍棘鲷(Acanthopagrus latus)幼鱼为研究对象,观察了不同开孔形状(菱形、圆形、正方形)、不同开孔大小(2.5、5、7.5、10cm)人工鱼礁对鱼类的行为影响,并通过行为分析软件LoliTtrackVersion5对黄鳍棘鲷幼鱼的平均速度、平均加速度、平均转弯速度、活动时间百分比以及平均分布坐标位置进行分析。结果表明,在放入人工鱼礁后黄鳍棘鲷幼鱼在礁区的平均分布率有明显上升,幼鱼在菱形开孔实验组人工鱼礁区的平均分布率最高,为(27.32±4.93)%,其次为正方形和圆形开孔实验组,分别为(25.48±3.41)%和(19.83±5.59)%。另外开孔大小为7.50 cm的实验组中,黄鳍棘鲷幼鱼在VI区的平均分布率最高,为(29.18±4.75)%;开孔大小为2.50 cm和5.00 cm的实验组中在VI区的平均分布率次之,分别为(23.45±3.86)%及(23.04±5.51)%;开孔大小为10.00 cm的实验组最低,为(21.17±5.14)%。在运动能力方面,黄鳍棘鲷幼鱼的平均速度、平均加...     

Diplodus spp. assemblages on artificial reefs: importance for near shore fisheries

Abstract  Artificial reefs have been deployed along the southern coast of Portugal (Algarve) since 1990 to enhance artisanal fisheries. The objectives of this study were to: (1) describe the colonisation process; (2) assess the role of the artificial reefs in terms of juvenile recruitment and growth and as mating/spawning areas and (3) evaluate the potential of artificial reefs as near shore artisanal fishing grounds for three economically important fish species, Diplodus bellottii (Steindachner), Diplodus sargus (L.) and Diplodus vulgaris (Geoffroy Saint-Hilaire). The fish assemblages were monitored after the deployment of a large artificial reef (Faro/Ancão) in 2002. Colonisation rates for the three species were fast. Artificial reefs play a multiple role for Diplodus spp., acting as recruitment, growth and nursery areas for juveniles, and spawning/mating areas for adults, and can thus be considered essential fish habitat. Three months after deployment of the artificial reefs, exploitable biomass was 16, 29 and 8 kg per reef group, respectively, for D. bellotti , D. sargus and D. vulgaris . These results indicate that artificial reefs quickly become good fishing grounds, where suitable financial yields may be obtained by fisher. Moreover, the artificial reefs became new and alternative fishing grounds, allowing reduction of fishing effort over traditional rocky areas that are scarce along the Algarve coast. Management measures for artificial reefs, in terms of fishing strategies, are discussed.     

The effects of epibenthic communities on reef fishes in the northern Gulf of Mexico

Abstract  Reef fishes were compared between artificial reefs with ( n  =   20) and without ( n  =   20) epibenthic communities in the northern Gulf of Mexico. Artificial reefs were built in June 2003; half were coated with copper-based paint to prevent epibenthic community development. Reefs were surveyed by SCUBA divers to estimate fish abundance in the autumn and winter 2003 and spring 2004. Total fish abundance and abundance of red snapper, Lutjanus campechanus (Poey), and gray triggerfish, Balistes capriscus Gmelin, were significantly ( P  ≤   0.05) higher on reefs with epibenthic communities. In the spring 2004, the abundance of belted sandfish, Serranus subligarius (Cope), the size of red snapper and community measures of diversity and evenness were significantly ( P  ≤   0.05) greater on unpainted reefs. These significant differences provide evidence that reef fishes were positively affected by the presence of epibenthic organisms that probably provided increased food resources.     

Multidecadal otolith growth histories for red and gray snapper (Lutjanus spp.) in the northern Gulf of Mexico,USA

Dendrochronology (tree‐ring analysis) techniques were applied to develop chronologies from the annual growth‐increment widths of red snapper (Lutjanus campechanus) and gray snapper (Lutjanus griseus) otoliths sampled from the northern Gulf of Mexico, USA. Growth increment widths showed considerable synchrony within and across species, indicating that some component of environmental variability influenced growth. The final, exactly dated red snapper chronology continuously spanned 1975 through 2003, while the gray snapper chronology continuously spanned 1975 through 2006. To determine baseline climate‐growth relationships, chronologies were compared to monthly averages of sea surface temperatures, U winds (west to east), V winds (south to north), and Mississippi River discharge. The gray snapper chronology significantly (P < 0.01) correlated with winds and temperature in March and April, while the red snapper chronology correlated with winds in March. Principal components regression including springtime winds and temperature accounted for 28 and 52% of the variance in the red and gray snapper chronologies, respectively. These results indicate that snapper growth was favored by warm sea surface temperatures and onshore winds from the southeast to the northwest in March and April. Overall, this study provides preliminary, baseline information regarding the association between climate and growth for these commercially important snapper species.     

防城港人工礁区内5种恋礁鱼类的声学标志跟踪

为了解人工鱼礁区鱼类的活动特点及使用超声波遥测方法进行人工鱼礁区鱼类研究的可行性, 2017年7月7日至9月8日于防城港人工鱼礁区利用Vemco定位系统(Vemco position system, VPS)对5种北部湾沿海常见的野生恋礁性鱼类共9尾[体长(21.7±3.8) cm,体重(314±186) g]进行超声波标志遥测跟踪。结果表明, 9尾鱼中的3尾定位效果较为理想(1749～9591个定位结果),活动范围较小,其中100%最小凸多边形(minimum convex polygon, MCPs)范围为12687.6～17123.2 m^2。而50%和95%核心利用分布(Kernelutilizationdistribution,KUDs)范围为5788.1～8708.9 m^2和10240.5～16463.7 m^2。另6尾鱼未取得理想的定位效果(0～14个定位结果),接收机接收回的定位数据可以被检测,表明鱼依然在礁区附近活动。在游离检测范围28～51 d后又有信号返回,说明样本鱼对人工鱼礁环境有一定的偏好性,研究期间样本鱼表现出一定的活动深度变化规律,在15:00～22:00时段活动深度相对较浅,主要集中于人工鱼礁礁体上方(距水底5 m以上)。研究表明,应用超声波遥测技术可以了解鱼类在自然生活状态下的活动特点,可作为鱼类研究的有效手段加以应用。     

Advection of anchovy (Engraulis encrasicolus) larvae along the Catalan continental slope (NW Mediterranean)

The Gulf of Lions is one of the main anchovy (Engraulis encrasicolus) spawning areas in the NW Mediterranean. During the spring, low‐salinity surface water from the outflow of the Rhône is advected by the shelf‐slope current along the continental slope off the Catalan coast. In June 2000, a Lagrangian experiment tracking these low‐salinity surface waters was conducted to assess the importance of this transport mechanism for anchovy larvae and to determine the suitability of the tracked surface waters for survival of anchovy larvae. The experiment consisted of sampling the tracked water parcel for 10 days with three drifters launched at the core of the shelf‐slope current where low‐salinity surface waters were detected. The survey was completed by sampling the surrounding waters. Anchovy larvae from the spawning area in the Gulf of Lions were advected towards the south in the low‐salinity waters. The size increase of anchovy larvae throughout the Lagrangian tracking closely followed the general growth rate calculated by otolith analysis (0.65 mm day⁻¹). However, advection by the current was not the only mechanism of anchovy larval transport. A series of anticyclonic eddies, originated in the Gulf of Lions and advected southwards, seemed to play a complementary role in the transport of larvae from the spawning ground towards the nursery areas. These eddies not only contributed to larval transport but also prevented their dispersion. These transport and aggregation mechanisms may be important for anchovy populations along the Catalan coast and require further study.     

人工鱼礁投放误差分布研究

人工鱼礁建设海域的鱼礁实际分布状态与设计方案的鱼礁配置组合之间往往存在着不同程度的偏离差异,而如何从单位鱼礁和鱼礁群层面上评估鱼礁投放误差,是评价人工鱼礁投放质量乃至建设效果的基本前提。本实验选择港湾、岛礁、开阔等典型海域的人工鱼礁区,以重心位置、外围面积、重叠面积、单体数量以及平均间距为指标,在单位鱼礁的层面上,对实际投放的人工鱼礁进行误差计算与分析。结果显示,各指标的误差整体上基本服从正态分布,某个鱼礁区指标的误差可能服从多种合理的拟合分布,不同投礁海域的同一个误差指标具有类似的分布规律,不同的误差指标拟合分布的情况也有可能相同。重心位置误差、重叠面积误差以及单体数量误差在不同区域极限误差相同,其标准化误差分布范围分别为[0,1]、[0,1]、[0,0.451],而其他误差要素在不同区域得到的极限误差略有差异,总体上,外围面积误差分布在[0,1]之间,礁体间距误差和总体误差的分布范围分别为[0,1],[0,0.890]。通过对人工鱼礁投放误差规律及误差范围的分析,才能对投放误差进行等级划分,进一步为鱼礁投放评价标准的划分提供依据。