The distribution of larval fishes of the Charleston Gyre Region off the southeastern United States in winter shaped by mesoscale, cyclonic eddies

Serial, cyclonic, mesoscale eddies arise just north of the Charleston Bump, a topographical rise on the continental slope and Blake Plateau, and characterize the U.S. outer shelf and upper slope in the region of the Charleston Gyre. This region was transected during the winters of 2000, 2001, and 2002, and hydrographic data and larval fishes were collected. The hydrodynamics of the cyclonic eddies of the Charleston Gyre shape the distribution of larval fishes by mixing larvae from the outer continental shelf and the Gulf Stream and entraining them into the eddy circulation at the peripheral margins, the wrap-around filaments. Over all years and transects (those that intercepted eddies and those that did not), chlorophyll a concentrations, zooplankton displacement volumes, and larval fish concentrations were positively correlated. Chlorophyll a concentrations were highest in filaments that wrapped around eddies, and zooplankton displacement volumes were highest in the continental shelf–Gulf Stream–frontal mix. Overall, the concentration of all larval fishes declined from inshore to offshore with highest concentrations occurring over the outer shelf. Collections produced larvae from 91 fish families representing continental shelf and oceanic species. The larvae of shelf-spawned fishes—Atlantic Menhaden Brevoortia tyrannus, Round Herring Etrumeus teres, Spot Leiostomus xanthurus, and Atlantic Croaker Micropogonias undulatus—were most concentrated over the outer shelf and in the continental shelf–Gulf Stream–frontal mix. The larvae of ocean-spawned fishes—lanternfishes, bristlemouths, and lightfishes—were more evenly dispersed in low concentrations across the outer shelf and upper slope, the highest typically in the Gulf Stream and Sargasso Sea, except for lightfishes that were highest in the continental shelf–Gulf Stream–frontal mix. Detrended correspondence analysis rendered groups of larval fishes that corresponded with a gradient between the continental shelf and Gulf Stream and Sargasso Sea. Eddies propagate northeastward with a residence time on the outer shelf and upper slope of ∼1 month, the same duration as the larval period of most fishes. The pelagic habitat afforded by eddies and fronts of the Charleston Gyre region can be exploited as nursery areas for feeding and growth of larval fishes within the southeastern Atlantic continental shelf ecosystem of the U.S. Eddies, and the nursery habitat they provide, translocate larvae northeastward.

An ecological characterization of the marine resources of Vieques, Puerto Rico. Part I: Historical data synthesis

From the 1940s until 2003, portions of the island of Vieques, a municipality within the Commonwealth of Puerto Rico, were used by the US Navy as a base and training facility, resulting in development and zoning history that differ in comparison to other Caribbean islands. The majority of former Navy lands are now under the jurisdiction of the Department of the Interior’s Fish and Wildlife Service as a National Wildlife Refuge, while a smaller percentage of land was transferred to the Vieques municipality and the Puerto Rico Conservation Trust. An analysis of the distribution and status of the marine resources is timely in light of the recent land transfer, increases in development and tourism, and potential changes in marine zoning around the island. To meet this need, NOAA’s Biogeography Branch, in cooperation with the Office of Response and Restoration and other local and regional partners, conducted Part I of an ecological characterization to integrate historical data and research into a synthesis report. The overall objective of this report is to provide resource managers and residents a comprehensive characterization of the marine resources of Vieques to support research, monitoring, and management. For example, knowledge of the spatial distribution of physical features, habitats, and biological communities is necessary to make an informed decision of the establishment and placement of a marine protected area (MPA). The report is divided into chapters based on the physical environment (e.g., climate, geology, bathymetry), habitat types (e.g., reefs and hardbottom, seagrasses, mangroves) and major faunal groups (e.g. fish, turtles, birds). Each section includes five subsections: an overview, description of the relevant literature, methods of analysis, information on the distribution, status and trends of the particular resource, and a discussion of ecological linkages with other components of the Vieques marine ecosystem and surrounding environment. The physical environment of Vieques is similar to other islands within the Greater Antilles chain, with some distinctions. The warm, tropical climate of Vieques, mediated by the northeasterly trade winds, is characterized by a dry season (December-April) and a rainy season (May-November), the latter of which is characterized by the occasional passage of tropical cyclones. Compared to mainland Puerto Rico, Vieques is characterized by lower elevation, less annual precipitation, and higher average temperatures. The amount of annual precipitation also varies spatially within Vieques, with the western portion of the island receiving higher amounts of rainfall than further east. While the North Equatorial Current dominates the circulation pattern in the Greater Antilles region, small scale current patterns specific to Vieques are not as well characterized. These physical processes are important factors mitigating the distribution and composition of marine benthic habitats around Vieques. In general, the topography of Vieques is characterized by rolling hills. Mt. Pirata, the tallest point at 301 m, is located near the southwest coast. In the absence of island wide sedimentation measurements, information on land cover, slope, precipitation, and soil type were used to estimate relative erosion potential and sediment delivery for each watershed. While slope and precipitation amount are the primary driving factors controlling runoff, land use practices such as urban development, military activity, road construction, and agriculture can increase the delivery of pollution and sediments to coastal waters. Due to the recent land transfer, increased development and tourism is expected, which may result in changes in the input of sediments to the coastal environment.

Analyzing and mapping fish assemblages off central California, USA

This study describes fish assemblages and their spatial patterns off the coast of California from Point Arena to Point Sal, by combining the results of the multivariate analyses of several fisheries datasets with a geographic information system. In order to provide comprehensive spatial coverage for the areas of inshore, continental shelf, and continental slope, three fisheries datasets were analyzed: 1) Inshore: the California Department of Fish and Game dataset of fishery-dependent commercial passenger fishing vessel trips that targeted rockfish; 2) Continental Shelf: the National Marine Fisheries Service (NMFS) fishery-independent bottom trawls; and 3) Continental Slope: the NMFS fishery-independent bottom trawls on the continental slope. One-hundred seven species were analyzed. These species represented those captured in at least 5% of the fishing trips or trawls in at least one of the three data sets. We analyzed each of the three datasets separately, and the three sets of results were combined to define 28 species assemblages and 23 site groups. A species assemblage consisted of species caught together, whereas a site group consisted of fishing trips or trawl locations that tended to have the same species assemblages. At the scale of these datasets, 97% of all site groups were significantly segregated by depth.

Distribution of persistent organic contaminants in canyons and on the continental shelf off central California

The National Status and Trends (NS&T) Program has conducted studies to determine the spatial extent and severity of chemical contamination and associated adverse biological effects in coastal bays and estuaries of the United States since 1991. Sediment contamination in U.S. coastal areas is a major environmental issue because of its potential toxic effects on biological resources and often, indirectly, on human health. Thus, characterizing and delineating areas of sediment contamination and toxicity and demonstrating their effect(s) on benthic living resources are therefore important goals of coastal resource management at NOAA. The National Centers for Coastal Ocean Science, and the Office of National Marine Sanctuaries, in cooperation with the U.S. Geological Survey (USGS), University of California Moss Landing Marine Lab (MLML), and the Monterey Bay Aquarium Research Institute (MBARI), conducted ecosystem monitoring and characterization studies within and between marine sanctuaries along the California coast in 2002 and 2004 on the NOAA RV McArthur. One of the objectives was to perform a systematic assessment of the chemical and physical habitats and associated biological communities in soft bottom habitats on the continental shelf and slope in the central California region. This report addresses the magnitude and extent of chemical contamination, and contaminant transport patterns in the region. Ongoing studies of the benthic community are in progress and will be reported in an integrated assessment of habitat quality and the parameters that govern natural resource distributions on the continental margin and in canyons in the region.

Radiometric validation of age, growth, and longevity for the blackgill rockfish (Sebastes melanostomus)

As nearshore fish populations decline, many commercial fishermen have shifted fishing effort to deeper continental slope habitats to target fishes for which biological information is limited. One such fishery that developed in the northeastern Pacific Ocean in the early 1980s was for the blackgill rockfish (Sebastes melanostomus), a deep-dwelling (300−800 m) species that congregates over rocky pinnacles, mainly from southern California to southern Oregon. Growth zone-derived age estimates from otolith thin sections were compared to ages obtained from the radioactive disequilibria of 210Pb, in relation to its parent, 226Ra, in otolith cores of blackgill rockfish. Age estimates were validated up to 41 years, and a strong pattern of agreement supported a longevity exceeding 90 years. Age and length data fitted to the von Bertalanffy growth function indicated that blackgill rockfish are slow-growing (k= 0.040 females, 0.068 males) and that females grow slower than males, but reach a greater length. Age at 50% maturity, derived from previously published length-at-maturity estimates, was 17 years for males and 21 years for females. The results of this study agree with general life history traits already recognized for many Sebastes species, such as long life, slow growth, and late age at maturation. These traits may undermine the sustainability of blackgill rockfish populations when heavy fishing pressure, such as that which occurred in the 1980s, is applied.

Abundance of cetatceans in the southern U.S. North Atlantic Ocean during summer 1998

The U.S. Marine Mammal Protection Act requires that the abundance of marine mammals in U.S. waters be assessed. Because this requirement had not been met for a large portion of the North Atlantic Ocean (U.S. waters south of Maryland), a ship-based, line-transect survey was conducted with a 68 m research ship between Maryland (38.00°N) and central Florida (28.00°N) from the 10-m isobath to the boundary of the U.S. Exclusive Economic Zone. The study area (573,000 km2) was surveyed between 8 July and 17 August 1998. Minimum abundance estimates were based on 4163 km of effort and 217 sightings of at least 13 cetacean species and other taxonomic categories. The most commonly sighted species (number of groups) were bottlenose dolphins, Tursiops truncatus (38); sperm whales, Physeter macrocephalus (29); Atlantic spotted dolphins, Stenella frontalis (28); and Risso’s dolphins, Grampus griseus (22). The most abundant species (abundance; coeffi cient of variation) were Atlantic spotted dolphins (14,438; 0.63); bottlenose dolphins (13,085; 0.40); pantropical spotted dolphins, S. attenuate (12,747; 0.56); striped dolphins, S. coeruleoalba (10,225; 0.91); and Risso’s dolphins (9533; 0.50). The abundance estimate for the Clymene dolphin, S. clymene (6086; 0.93), is the first for the U.S. Atlantic Ocean. Sperm whales were the most abundant large whale (1181; 0.51). Abundances for other species or taxonomic categories ranged from 20 to 5109. There were an estimated 77,139 (0.23) cetaceans in the study area. Bottlenose dolphins and Atlantic spotted dolphins were encountered primarily in continental shelf (<200 m) and continental slope waters (200−2000 m). All other species were generally sighted in oceanic waters (>200 m). The distribution of some species varied north to south. Striped dolphins, Clymene dolphins, and sperm whales were sighted primarily in the northern part of the study area; whereas pantropical spotted dolphins were sighted primarily in the southern portion.

A nearsurface, daytime occurrence of two mesopelagic fish species (Stenobrachius leucopsarus and Leuroglossus schmidti) in a glacial fjord

The northern lampfish (Stenobrachius leucopsarus, family Myctophidae) and northern smoothtongue (Leuroglossus schmidti, family Bathylagidae) are mesopelagic fishes, defined by their vertical distribution in the mesopelagic zone (200–1000 m) during daylight hours. Northern lampfish range from the Bering Sea to southern California (Shimada, 1948), where their abundance is highest along the continental slope and decreases over the continental shelf. They are the most abundant species in the mesopelagic zone of the Bering Sea (Pearcy et al., 1977; Sobolevsky et al., 1996), the Gulf of Alaska (Purcell, 1996), and the eastern North Pacific Ocean off Oregon (Pearcy, 1964; Pearcy et al., 1977). Northern smoothtongue also concentrate in areas bordering the continental slope and are widely distributed from southern British Columbia to the Bering Sea (Peden, 1981) and are very abundant in the Okhotsk Sea (Sobolevsky et al., 1996).

Rapid δ18O and δ13C isotopic shifts in late Pleistocene marine varves on the California margin

Upper Pleistocene sediments on the continental slope off Northern California contain alternations of varves and bioturbation produced by fluctuations in intensity of the coastal upwelling system. Stable isotopic analyses of benthic Foraminifera across a particularly well developed varve/bioturbation sequence deposited ~26,000 years ago reveal rapid shifts of ~0.25‰ in δ18O and ~0.4‰ in δ13C. The δ18O shift occurs within a varved section. Based on varve counts, the isotopic change occurred in less than 100 years. Timing and magnitude of the shift coincide with similar shifts observed in almost all other high-resolution δ18O records that have been interpreted as primarily representing global in-volume fluctuations.

Geochemical evidence for enhanced upwelling and organic productivity during the late Quaternary on the continental margin of northern California

EXTRACT (SEE PDF FOR FULL ABSTRACT): Laminated sediments are preserved in upper Pleistocene sections of cores collected on the continental slope at water depths within the present oxygen-minimum zone from at least as far north as the Klamath River and as far south as Point Sur. Comparison of sediment components in the laminae with those delivered to sediment traps as pelagic marine "snow" show the dark/light lamination couplets are indeed annual (varves). ... The presence of carbon-, sulfur-, and metal-rich sediments, as well as lack of bioturbation, all support the theory that the oxygen-minimum zone in the northeastern Pacific Ocean was more intense - in fact, anoxic - during the late Pleistocene in response to greater coastal upwelling and higher organic productivity.

Regional context of the climate of H.J. Andrews Experimental Forest, Oregon

H.J. Andrews Experimental Forest is a 6400 ha forest of Douglas fir, western hemlock, and Pacific silver fir located in, and typical of, the central portion of the western slope of the Cascade mountain range of Oregon. The forest is one of 19 sites in the Long-Term Ecological Research (LTER) program sponsored by the National Science Foundation. ... Because of the scientific significance of Andrews Forest, it is important to investigate the temporal variability of annual and seasonal temperature and precipitation values at the site and identify past times of anomalous climatic conditions. It is also important to establish quantitatively the relationships between the climate of Andrews Forest and that of its surrounding area and, hence, place the climate of Andrews Forest into its regional context.

新疆天山中段北坡地区现代孢粉学研究

新疆中部地区位于西北内陆干旱一半干旱区，是欧亚大陆的地理中心，是中纬度内陆干旱区代表性区域，也是全球变化敏感区域之一，基本特点是气候干旱、水资源匮乏、植被稀少、荒漠广布，生态系统脆弱。在研究区域内，天山山脉海拔高度差异5 000 m左右，随海拔梯度下降依次出现高山冰雪带、高山亚高山草甸带、森林带、草原带、荒漠带、沙漠带等明显完整的植被垂直带，是开展现代孢粉学和植被变化研究的理想地点。本报告在立足于该区前人工作的基础上，从表土花粉、空气花粉和现代植被之间的关系入手开展现代孢粉学研究，探讨了花粉与植被的关系。 在研究区内，选择新疆阜康市和吉木萨尔县为研究地点，设计了一条从天山博格达峰附近雪线开始直至古尔班通古特沙漠长约100 km、宽约20 km的样带。沿样带，从高山座垫植被和草甸带开始，经过中海拔地带的云杉林，置到低海拔的荒漠，在山地海拔每下降20～100 m采集一个表土花粉样品，平原每间隔10～20 km采集一个表土花粉样品，同时做现代植被调查，共采集80个表土花粉样品和调查了86个现代植被样方;在天山乌鲁木齐河河源区的大西沟，从一号冰川前缘开始，沿山谷向下直到谷口，按海拔100 m间隔采集了14个表土样品，对表土花粉与植被之间的关系进行了探讨。为了弄清空气花粉传播、散布与气象因子和植被的关系，沿样带从高山到沙漠分别在天池气象站、中国科学院阜康荒漠生态系统定位研究站和北沙窝草炭试验地设置了三个风标式空气花粉收集器，从2001年7月至2002年7月连续收集空气花粉雨，收集了跨2个年度1周年的1 14个空气花粉样品，依据分析结果研究了空气花粉的传播和散布规律以及与表土花粉和植被之间的关系，这在新疆地区乃至全国尚属首次。 根据表土花粉分析结果和现代植被样方资料的分析以及天山中段主要植物种类沿海拔高度的分布特征，天山中段北坡垂直植被带谱为：高山座垫植被(>3 400 m)、高山亚高山草甸(3 400-2 700 m)、山地云杉林(2 700-1 720 m)、森林草原过渡带(1 720-1 300 m)、蒿类荒漠(1 300-700 m)和典型荒漠(<700 m)。表土花粉谱基本上反映了相同海拔高度的现代植被带，特别是在云杉林带，表土中雪岭云杉(Picea schrenkiana)花粉占优势;在蒿类荒漠植被带表土中蒿属（Artemisia）植物花粉非常丰富;在典型荒漠植被带的表土中藜科(Chenopodiaceae)植物花粉占绝对优势，因此可依据这些建群种植物花粉含量峰值的位置划分植物群落。 空气花粉样品分析结果表明：空气中花粉主要是现生植物当年生长产出的花粉，盛花期的花粉数量能较好地反映当地的植被状况。空气中的乔木植物花粉主要有云杉(Picea)，其次是柳属（Salix）;灌木草本植物花粉主要是藜科和蒿属，其次是菊科(Compositae)、禾本科(Gramineae)、柽柳科(Tamaricaceae)和麻黄属(Ephedra);空气中的花粉数量与植物的花期相对应，云杉等乔木植物盛花期在夏季5月末至7月初，灌木草本植物盛花期在夏秋季节。气温、降水、风速和风向等气象条件对空气中花粉数量有很大影响，其中风速和风向影响最大。从空气花粉和表土花粉的分析结果与现生植被对比，新疆中部地区的山谷上升气流是导致花粉“爬坡”现象的主要动力，在一定条件下，上升气流搬运花粉的数量和能力是十分可观的。 空气中的花粉是现生植物当年生长产出的花粉，表土中的花粉是多年花粉落地沉积的积累，植物盖度大，该植物的花粉在空气中和表土中数量相对就大。在新疆中部地区，空气花粉能反映当地和附近周边方圆约50 km的植被状况，其花粉组合特征与表土花粉和当地现生植被分布的对比研究，可以较好地寻找花粉与植被的关系。本研究报告的研究成果不仅为新疆地区的孢粉学研究增添新的内容，而且将有助于合理解释新疆地层中、尤其是第四纪以来的地层孢粉，较客观地恢复过去的植被景观，同时可为本地区的大气环境检测提供有重要价值的参考资料。

长白山自然保护区北坡森林结构、植物多样性与碳储量40余年的变化

长白山自然保护区始建于1960年，位于北坡的红松针阔叶混交林森林生态系统是我国东北地区典型温带地带性森林植被之一，面临着全球气候变化和人类干扰的双重影响。 本研究以间隔43年的野外调查数据为基础，对1963年和2006年的长白山自然保护区北坡海拔800~1700m的森林植物群落进行对比分析，得到该区域的森林结构、植物多样性与碳储量的变化特点，讨论森林动态变化与人类活动、气候变化的关系，评价长白山自然保护区的保护效果： 对长白山北坡森林沿海拔梯度的森林结构和植物多样性的分析表明：群落的整体空间格局保存完好，植物种类变化不大，乔木层的建群种的种类基本不变，植物多样性与海拔高度呈负相关关系;林下层植物多样性受小环境影响，与海拔高度无明显相关。 以红松（Pinus koraiensis）针阔混交林、红松针叶混交林和云冷杉暗针叶林三种类型为单元分别研究各森林类型的多样性变化：α多样测度选择物种丰富度、Shannon-Wiener和Pielou均匀度指数，较好体现了样地内发生的多样性变化，灌木层和草本层多样性明显下降，一些稀有种和药用物种消失，红松等原优势物种有衰退趋势，阔叶树比例增大;β多样性测度选取Cody指数，体现出海拔梯度上的植被空间格局细节变化，演替层特别是阔叶树的物种更替变化有向高海拔移动的趋势。 对森林生态系统各层次碳储量进行估算：乔木层和灌木层采用维量法，对灌木层自建生长回归方程;草本层、枯枝落叶层采取收获法;植物细根采取根钻法;土壤采取土壤深度加权法。碳密度估算结果都与前人研究结果相似。各类型植被碳库总碳密度都达到170 t/hm2，远远高于国内平均森林植被碳库密度值44.9 t/hm2。 乔木层43年来的碳储量变化都无显著性差异，但仍表现出：阔叶树种碳储量上升，特别在高海拔类型这种变化更加明显;针叶树种碳储量在暗针叶林内大幅下降;树干的碳库分配比例都有所减少，表明植被碳库正存在向不稳定性方向发展的趋势。针阔混交林和暗针叶林的土壤碳储量，与植被碳库出现相反的变化趋势，整体碳库保持在一个相对平衡的状态。 推测造成这种变化的原因是：禁止砍伐等保护措施的实施，基本保存了乔木层垂直分布格局，而气候变暖使阔叶树种比例大幅增加，采集松籽等人类生产及旅游活动对林下层植被影响破坏较大。提议加强保护区内管理力度和规划，以减缓长白山北坡森林群落的不稳定变化趋势。

Marine fisheries development in India, 2000 AD: a perspective

The status of marine fisheries research and development in India is discussed and the need for a high power national body to coordinate these activities is stressed. Priority areas for research and development have been outlined. It has been stressed that the strategy should be to achieve a production target of 3 million tonnes on the capture fisheries front (2.5 million tonnes from the inner shelf and 0.5 million tonnes from the outer shelf and slope areas) and 1 million tonne through aquaculture by 2000 AD.

A preliminary account and review of the simple methods for determining the operational parameters of fishing gear, underwater, with notes on its application

An account and review of the simple methods for determining the operational parameters of fishing gear, underwater, such a tilt of otter boards (outwards or inwards, forwards or afterwards), vertical height of net, its horizontal spread, angle of divergence at bosom, spread between wing tips, angle of inclination of danlenos, butterfly, slope of legs and sweep-line has been given. The relationship of distance between the otter boards spread and the vertical height of net has been obtained as generally linear. The possibilities of regulating the vertical height of net (dependent variate) and spread of otter boards (independent variate) for increasing the fishing efficiency has been discussed. The angle of attack of oval shaped otter boards used during the operations still remain undetermined, however, it has been explained how the best angle of attack for increasing the efficiency of gear can be obtained by regulating the ratio of depth to warp for a given net. The inadequacy of the mere indices of catch per hour of trawling in comparing the relative efficiency of trawls in gear research studies has been indicated. The importance of estimating the operational parameters and its application to commercial fisheries depending upon the distribution pattern of fish and in gear research has been discussed. The efficiency of the jelly bottle method has been compared statistically with the observations made on the trawl gear underwater with instruments.

SUB-BAND CODING TECHNIQUES FOR ROBUST 4. 8 TO 8 kb/s SPEECH CODERS.

This paper describes a speech coding technique that has been developed in order to provide a method of digitising speech at bit rates in the range 4. 8 to 8 kb/s, that is insensitive to the effects of acoustic background noise and bit errors on the digital link. The main aim has been to develop a coding scheme which provides speech quality and robustness against noise and errors that is similar to a 16000 b/s continuously variable slope delta (CVSD) coder, but which operates at half its data rate or less. A desirable aim was to keep the complexity of the coding scheme within the scope of what could reasonably be handled by current signal processing chips or by a single custom integrated circuit. Applications areas include mobile radio and small Satcomms terminals.