Scale-dependent habitat use by a large free-ranging predator,the Mediterranean fin whale

Since the heterogeneity of oceanographic conditions drives abundance, distribution, and availability of prey, it is essential to understand how foraging predators interact with their dynamic environment at various spatial and temporal scales. We examined the spatio-temporal relationships between oceanographic features and abundance of fin whales (Balaenoptera physalus), the largest free-ranging predator in the Western Mediterranean Sea (WM), through two independent approaches. First, spatial modeling was used to estimate whale density, using waiting distance (the distance between detections) for fin whales along ferry routes across the WM, in relation to remotely sensed oceanographic parameters. At a large scale (basin and year), fin whales exhibited fidelity to the northern WM with a summer-aggregated and winter-dispersed pattern. At mesoscale (20–100 km), whales were found in colder, saltier (from an on-board system) and dynamic areas defined by steep altimetric and temperature gradients. Second, using an independent fin whale satellite tracking dataset, we showed that tracked whales were effectively preferentially located in favorable habitats, i.e. in areas of high predicted densities as identified by our previous model using oceanographic data contemporaneous to the tracking period. We suggest that the large-scale fidelity corresponds to temporally and spatially predictable habitat of whale favorite prey, the northern krill (Meganyctiphanes norvegica), while mesoscale relationships are likely to identify areas of high prey concentration and availability.     

Seasat data applications by commercial users

Abstract

The Seasat Program was initiated as a proof‐of‐concept mission to evaluate the effectiveness of remotely sensed oceanographic phenomena from a satellite platform. From inception, this program has been user‐oriented. These users, within the academic, government, and commercial ocean communities, have served as the architects of the program and are continuing to be involved in the validation and application of the satellite‐derived data. While an early failure of the satellite deprived the user communities of a real‐time multiseasonal data set, the program did yield a rare and valuable archive of data now being analyzed and validated by a variety of users.

A unique program of evaluation exists to assess the impact of satellite‐derived oceanographic observations in several segments of the commercial sector. Commercial users from such segments as marine transportation, ocean mining, offshore oil and gas exploration and operations, marine Fisheries, and marine safety are analyzing Seasat data to understand the operational and economic impact of such data on their various business activities.

Early results from these studies show that satellite observations alone can provide commercial users with historical data for new and remote areas of operation which, to obtain by in situ measurements, would require enormous expenditures of funds for oceanographic instrumentation. More significantly, these studies are showing that timely oceanographic and weather forecasts, improved by the use of satellite‐derived observations of winds, waves, and surface temperatures, can result in more efficient and safe operations, yielding industry savings of millions of dollars annually.     

Cetacean habitat in the northern oceanic Gulf of Mexico

Cetaceans (whales and dolphins) are diverse and abundant upper trophic level predators in the Gulf of Mexico, a semi-enclosed, intercontinental sea with a total area of about 1.5 million km². The objectives of this study were to better define the habitat of cetaceans in the northern oceanic Gulf of Mexico. An integrated methodology was used that included visual surveys and hydrographic collections from ships. Near real-time sea surface altimetry from the TOPEX/POSEIDON and ERS satellites was used during ship surveys to determine the location of hydrographic features (e.g., cyclones, anticyclones and confluence zones). Archival satellite sea surface altimetry data were also used to retrospectively determine the location of hydrographic features for analysis with earlier cetacean sightings. We estimated zooplankton and micronekton biomass using both net and acoustic sampling to indicate the amount of potential food available for higher trophic level foraging by cetaceans. Nineteen cetacean species were identified during ship surveys. Cetaceans were concentrated along the continental slope in or near cyclones and the confluence of cyclone–anticyclone eddy pairs, mesoscale features with locally concentrated zooplankton and micronekton stocks that appear to develop in response to increased nutrient-rich water and primary production in the mixed layer. A significant relationship existed between integrated zooplankton biomass and integrated cephalopod paralarvae numbers, indicating that higher zooplankton and micronekton biomass may correlate with higher concentrations of cetacean prey. In the north-central Gulf, an additional factor affecting cetacean distribution may be the narrow continental shelf south of the Mississippi River delta. Low salinity, nutrient-rich water may occur over the continental slope near the mouth of the Mississippi (MOM) River or be entrained within the confluence of a cyclone–anticyclone eddy pair and transported beyond the continental slope. This creates a deep-water environment with locally enhanced primary and secondary productivity and may explain the presence of a resident, breeding population of sperm whales within 100 km of the Mississippi River delta. Overall, the results suggest that the amount of potential prey for cetaceans may be consistently greater in the cyclone, confluence areas, and south of the MOM, making them preferential areas for foraging. However, this may not be true for bottlenose dolphins, Atlantic spotted dolphins and possibly Bryde's whales, which typically occur on the continental shelf or along the shelf break outside of major influences of eddies.     

Remote sensing of ocean sound speed profiles by a perceptron neuralnetwork

A method is developed to estimate ocean sound speed profiles through synthesis of remotely measured environmental data and historical statistics of sound speed obtained at a remotely sensed location. Sound speed profiles are represented by an expansion of empirical orthogonal functions (EOF) of the historical sound speed variation, while the remotely sensed environmental data provide real-time information to determine the expansion coefficients. Environmental inputs are limited to sea surface temperature available from satellite infrared sensors, acoustic time-of-flight and ocean bottom temperature measurable from bottom mounted acoustic and thermal transducers. A multilayer perceptron neural network is implemented to learn the functional transformation from the measured environmental input to the desired EOF coefficient output on a set of representative sound speed profiles. Sea surface temperature, time-of-year, and time-of-flight from the acoustic multipath that maximally samples the vertical sound speed are found to be the dominant inputs. The trained network is computationally efficient and produces estimates for untrained environmental inputs with a mean error of 1.1-4.4 m/s     

Mesoscale features and phytoplankton biomass at the GoodHope line in the Southern Ocean during austral summer

Two sets of high-resolution subsurface hydrographic and underway surface chlorophyll a (Chl a) measurements are used, in conjunction with satellite remotely sensed data, to investigate the upper layer oceanography (mesoscale features and mixed layer depth variability) and phytoplankton biomass at the GoodHope line south of Africa, during the 2010–2011 austral summer. The link between physical parameters of the upper ocean, specifically frontal activity, to the spatially varying in situ and satellite measurements of Chl a concentrations is investigated. The observations provide evidence to show that the fronts act to both enhance phytoplankton biomass as well as to delimit regions of similar chlorophyll concentrations, although the front–chlorophyll relationships become obscure towards the end of the growing season due to bloom advection and ‘patchy’ Chl a behaviour. Satellite ocean colour measurements are compared to in situ chlorophyll measurements to assess the disparity between the two sampling techniques. The scientific value of the time-series of oceanographic observations collected at the GoodHope line between 2004 to present is being realised. Continued efforts in this programme are essential to better understand both the physical and biogeochemical dynamics of the upper ocean in the Atlantic sector of the Southern Ocean.     

The Atlantic Meridional Transect: overview and synthesis of data

The Atlantic Meridional Transect programme uses the twice-annual passage of the RRS James Clark Ross between the UK and the Falkland Islands, before and after the Antarctic research programme in the Austral Summer (see Aiken, J., & Bale, A. J. (2000). An introduction to the Atlantic Meridional Transect (AMT) Programme. Progress in Oceanography, this issue). This paper examines the scientific rationale for a spatially-extensive time and space series programme and reviews the relevant physical and biological oceanography of the Atlantic Ocean. The main scientific observations from the research programme are reported. These are set in the context of historical and contemporary observations pertinent to the principal objectives of the cruise, notably the satellite remotely sensed observations of ocean properties. The extent to which the programme goals have been realised by the research to date is assessed and discussed. New bio-optical signatures, which can be related to productivity parameters, have been derived. These can be used to interpret remotely sensed observations of ocean colour in terms of productivity and production processes such as the air/sea exchange of biogenic gases, which relate to the issues of climate change and the sustainability of marine ecosystems.     

Acoustic detections of blue whale (Balaenoptera musculus) and fin whale (B. physalus) sounds during a SURTASS LFA exercise

Acoustic data collected on the R/V Cory Chouest in February and March 1996 during an active operation of the U.S. Navy's surveillance-towed-array-sensor-system low-frequency-active (LFA) sonar were analyzed for blue whale (Balaenoptera musculus) and fin whale (B. physalus) sounds. Operational monitoring and mitigation protocols were implemented throughout the exercise to reduce the chances of an acoustic impact on marine mammals and sea turtles. The operational schedule did not include intentional "control" periods without transmissions but did include periods when the LFA sonar was not operating for other reasons (e.g., repairs). There were insufficient detections of blue whales for further analysis. Fin whale acoustic detection probabilities were calculated from the postprocessed data. A local-linear-regression analysis was used to compare fin whale detection probabilities from 2065 11-min intervals under conditions when the LFA sonar was and was not transmitting. There was an indication of a slightly higher probability of detecting fin whale sounds during periods when there were no LFA transmissions than during periods with transmissions. This may be the result of the following: 1) Reduced vocal activity by whales in response to LFA transmissions; 2) the effect of the mitigation protocols; or 3) some combination of 1) and 2). The data presently available do not allow one to distinguish definitively between these explanations, mainly because there were not enough data recorded for periods without LFA transmissions.     

A software workbench for estimating the effects of cumulative sound exposure in marine mammals

The U.S. Navy has initiated a multidisciplinary research and development program to study the Effects of Sound on the Marine Environment (ESME). As part of this effort, the Naval Research Laboratory (NRL) is developing a software workbench for estimating the effects of cumulative sound exposure on marine mammals. This paper describes the workbench, and presents some preliminary simulation results. The workbench integrates data sets and computer models contributed by researchers in the areas of oceanography, underwater acoustic propagation, and marine mammal physiology and behavior. Models are incorporated for simulating animal movement, for estimating the received acoustic time series along an animal's track, and for predicting temporary threshold shifts (TTSs) induced by acoustic exposure. TTS predictions are shown to be highly dependent upon both the environmental variables and the movement of the marine mammals.     

海洋雷达探测技术综述

通过简要回顾半个世纪以来海洋雷达技术发展历程的特点和规律,结合海洋雷达技术发展现状,介绍海洋雷达涉及的关键技术并进行应用场景分析。总结我国海洋雷达技术近30 a来的发展及其与国际水平的主要差距,提出"十三五"期间我国海洋雷达技术优先发展项目的建议,即超视距雷达广域海洋监测技术、浮动/机动平台高分辨率海洋雷达技术、新体制微波海洋雷达技术以及海洋雷达数据管理与应用技术等。     

Evidence that whales (Balaenoptera borealis) visit drifting fish aggregating devices: do their presence affect the processes underlying fish aggregation?

Evidence of the presence of a group of sei whales (Balaenoptera borealis) detected around drifting fish aggregating devices (FADs) was provided by omnidirectional multi‐beam sonar during a survey off the Seychelles (Indian Ocean). The short visit by the sei whales produced a significant change in the behaviour of the fish assemblage associated with the FAD. There was first a significant increase in fish density when the whales approached the FAD, then a marked decrease after the whales had moved away from the FAD. Furthermore, the fish density was still low, 3 h after the whales had left the FAD. We assume that the presence and behaviour of the sei whales led some of the fish initially associated with the FAD to move away from it. There has been a considerable increase in the use of drifting artificial FADs in the Indian Ocean in recent decades. The frequency of cetacean visits to drifting FADs in the Indian Ocean is unknown, but they may have a major impact on assemblages of pelagic fish species around FADs. The effect of marine mammals on FAD‐associated fish could be relevant to the ecological trap theory (FAD acting as a trap for their associated fish) because of their impact on the dynamics of fish aggregation processes, through commensalism and/or predator–prey interactions.     

Satellite infrared remote sensing observation of surface circulation of the northeast South China Sea in winter

I~IOX \The investigation of physical oceanography in the South China Sea dates from early in the17th century and was carried out by scientists from many countries, including the United StateS,the United Kingdoms, Japan, .Russia and so on, but the survey area was rather limited at thattime and the data which were collected were still fragmentary. Since the 20th century, the investigation on the sleuth China Sea has made great progreSS not only in the scale of survey, but alsoin the depth …     

鲸豚声信号实时采集与分析系统

本文设计了一套基于FPGA的鲸豚声信号实时数据采集与分析系统,在采集存储水族馆内声信号的同时,应用改进的HHT算法处理鲸豚叫声中的click信号,实现实时的甄别瓶鼻海豚和白鲸功能,可用于针对大型哺乳动物的远洋实时跟踪科考。     

南海东北部冬季表面环流的卫星红外遥感观测研究

根据 1 989～ 1 993年美国 NOAA系列卫星 (NOAA- 1 1、 1 2 )经过南海上空时所获取的数幅较完整的 AVHRR传感器映像资料 ,并结合 1 992年 3月 8日～ 2 7日在南海东北部海域现场观测所获的 CTD资料 ,揭示并讨论了发生在该海域的一些物理海洋学现象。结果表明 ,利用卫星映像和现场观测资料来分析和研究南海中的物理海洋学问题有着较好的互补性。卫星映像产生的海面温度场的分布基本上反映了现场观测的结果。通过对两者的综合分析 ,给出了一幅南海东北部冬季表面环流的形势图     

Influence of environmental variability on distribution and relative abundance of baleen whales (suborder Mysticeti) in the Gulf of California

The Gulf of California (GC) is one of the most productive seas in the Pacific Ocean because of several oceanographic phenomena that support many marine mammal species, particularly of the cetacean order. The environmental variability of the GC was analysed during the cold and warm periods of 2005 and 2006 and its effects on the distribution and relative abundance of baleen whales using sea surface temperature (SST) and chlorophyll a (Chl a) concentration. Satellite image analysis allowed us to detect important differences in both Chl a concentration and SST including cold to warm periods, even between the two cold periods and between the two warm periods. The cold periods had the highest number of whales: 99 individuals in 2005 and 183 in 2006, which were distributed along the entire gulf. Fewer animals were recorded in the warm period: 46 individuals in 2005 and 30 in 2006, which were mainly distributed in the northern part of the gulf. We concluded that SST influenced the relative abundance of baleen whales while Chl a concentration influenced their distribution.     

Revealing pelagic habitat use: the tagging of Pacific pelagics program

Tagging of Pacific pelagics (TOPP) is a pilot program of the Census of marine life (CoML) that will lead to understanding of pelagic habitat use by marine vertebrates and large squid in the North Pacific. Taking a multispecies approach, the TOPP project will use a range of electronic tag technologies to put the distribution and behavior of pelagic organisms in the context of the oceanography of the North Pacific. Tag-bearing animals will be used as autonomous ocean profilers to enhance sparse oceanographic observations for vast ocean regions. These autonomous ocean samplers will provide unprecedented coverage of the water column structure of the North Pacific. The temporal and spatial data generated by this project will provide an “organism-eye” view of several interactive oceanic regimes in the North Pacific. Twenty target species, including tunas, sharks, pinnipeds, cetaceans, seabirds, and marine turtles, will be monitored with electronic tags. Animal-collected oceanic data will be assimilated into global ocean databases, complement traditional methodologies and be used to help validate nearshore, regional, and basin scale ocean models. As more environmental information is gathered and delivered from the tagged animals, new insights will be obtained about their individual behaviors, as well as how diverse species have separately evolved to forage, reproduce, and survive in the vast pelagic environment. This multi-disciplinary approach will allow a novel merger of biological and physical data to provide a new understanding of the relationship between the movements and behaviors of marine organisms and oceanographic processes in the eastern North Pacific.     

El Niño related interannual variations in biological production in the North Pacific as evidenced by satellite and ship data

A recently proposed method for estimating nitrate and new production from remotely sensed data (Goes and Goes) allowed us to observe significant deviations from the normal in the quantum of winter-time nitrate injected into the euphotic column and its consumption by phytoplankton in the North Pacific following the El Niño event of 1997. Results from this study allowed us to observe large differences in the ways in which the El Niño event affected the western and the eastern margins of the North Pacific basin. For the western North Pacific, a long-term (1972–1992) historical record of oceanographic data provided us with clear evidence supporting of our findings from satellite observations. In the eastern North Pacific Ocean also, our results compared well with those previously reported (Wong, Whitney, Matear, & Iseki, 1998). While it is clear from this study that El Niño/La Niña oscillations can have a major influence on interannual variations in biological processes in the North Pacific, these results also serve to highlight the value of remote sensing as a tool for studying large regional to basin-scale biological oceanographic events.     

一种低功耗海洋定位信标的研制与应用

研制了一种低功耗的定位信标,用于长期服役于水下的海洋仪器回收出水后的定位搜寻工作。信标基于GPS射频组件开发,与仪器固定在一起,待整体浮出水面后,会启动位置信号发送程序,通过电信网络,将该信标的实时位置发送至终端。经测试表明,信标性能可靠,可为海洋仪器的安全工作和顺利回收提供保障。     

Study on the oceanic environments relating to the marine living resources

This is a review of the study on the oceanic environments relating to the marine living resources carried out since 1947, during more than 35 years which are the period of the authors oceanographic research life for fisheries. Its content consists of describing the outlines of, (1) the oceanographic study of the Subarctic Region of the Northwestern Pacific as the salmon living waters, (2) the study on dilution processes of the effluent in the coastal waters in relation to marine pollution, (3) the oceanographic study on transportation and diffusion of fish eggs and larvae in relation to the recruitment of living resources and (4) the study on forecasting of the fisheries and oceanographic conditions, and a short note on direction of fisheries oceanography expected to be studied in the future.     

遥感海洋初级生产力的生物－地理动力学问题

卫星遥感为大尺度海洋观测提供了一种可行方法。卫星资料应用于海洋初级生产力研究中最重要的是建立由海洋水色遥感资料得出的色素浓度计算初级生产力的合适算法。由于植物生理学方面的问题，建立一个合适的初级生产力算法有一定的困难。了解和确立水体中浮游植物的生理速率参数与分布结构动态是必要的。本文在分析水下光场和藻类光合作用光谱响应基础上，阐述了海洋初级生产力遥感中的生物－地理动力学问题。