52 resultados para Acoustic Immittance Measures


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The distinguished character of Particularly Sensitive Sea Areas (PSSAs) is that every application for PSSAs must be accompanied by Associated Protected Measures (APMs) which can make PSSAs efficient in practice.1 That is why APMs are regarded as the core feature of every PSSA.2 APM is “an international rule or standard that falls within the purview of an international maritime organization (IMO) and regulates international maritime activities for the protection of the area at risk.” So far, APMs have been approved by IMO as following: -Compulsory or recommended pilotage -Mandatory ship reporting -An area to be avoided -Traffic separation schemes -Discharge prohibition or regulations -Mandatory no anchoring areas -Deep water routes -Emission control areas (PDF contains 5 pages)

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In January 2006 the Maumee Remedial Action Plan (RAP) Committee submitted a State II Watershed Restoration Plan for the Maumee River Great Lakes Area of Concern (AOC) area located in NW Ohio to the State of Ohio for review and endorsement (MRAC, 2006). The plan was created in order to fulfill the requirements, needs and/or use of five water quality programs including: Ohio Department of Natural Resources (DNR) Watershed Coordinator Program; Ohio EPA Great Lakes RAP Program; Ohio DNR Coastal Non-point Source Pollution Control Program; Ohio EPA Total Maximum Daily Load Program; and US Fish & Wildlife Service Natural Resources Damage Program. The plan is intended to serve as a comprehensive regional management approach for all jurisdictions, agencies, organizations, and individuals who are working to restore the watershed, waterways and associated coastal zone. The plan includes: background information and mapping regarding hydrology, geology, ecoregions, and land use, and identifies key causes and sources for water quality concerns within the six 11-digit hydrological units (HUCs), and one large river unit that comprise the Maumee AOC. Tables were also prepared that contains detailed project lists for each major watershed and was organized to facilitate the prioritization of research and planning efforts. Also key to the plan and project tables is a reference to the Ohio DNR Coastal Management Measures that may benefit from the implementation of an identified project. This paper will examine the development of the measures and their importance for coastal management and watershed planning in the Maumee AOC. (PDF contains 4 pages)

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In addition to providing vital ecological services, coastal areas of North Carolina provide prized areas for habitation, recreation, and commercial fisheries. However, from a management perspective, the coasts of North Carolina are highly variable and complex. In-water constituents such as nutrients, suspended sediments, and chlorophyll a concentration can vary significantly over a broad spectrum of time and space scales. Rapid growth and land-use change continue to exert pressure on coastal lands. Coastal environments are also very vulnerable to short-term (e.g., hurricanes) and long-term (e.g., sea-level rise) natural changes that can result in significant loss of life, economic loss, or changes in coastal ecosystem functioning. Hence, the dynamic nature, effects of human-induced change over time, and vulnerability of coastal areas make it difficult to effectively monitor and manage these important state and national resources using traditional data collection technologies such as discrete monitoring stations and field surveys. In general, these approaches provide only a sparse network of data over limited time and space scales and generally are expensive and labor-intensive. Products derived from spectral images obtained by remote sensing instruments provide a unique vantage point from which to examine the dynamic nature of coastal environments. A primary advantage of remote sensing is that the altitude of observation provides a large-scale synoptic view relative to traditional field measurements. Equally important, the use of remote sensing for a broad range of research and environmental applications is now common due to major advances in data availability, data transfer, and computer technologies. To facilitate the widespread use of remote sensing products in North Carolina, the UNC Coastal Studies Institute (UNC-CSI) is developing the capability to acquire, process, and analyze remotely sensed data from several remote sensing instruments. In particular, UNC-CSI is developing regional remote sensing algorithms to examine the mobilization, transport, transformation, and fate of materials between coupled terrestrial and coastal ocean systems. To illustrate this work, we present the basic principles of remote sensing of coastal waters in the context of deriving information that supports efficient and effective management of coastal resources. (PDF contains 4 pages)

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This study examines how Thailand’s biodiversity conservation measures affect fishing communities, especially in the marine protected areas (MPAs) on the Andaman Sea coastline. It documents the various efforts of the local fishing communities to protect the resources in the area. Also included are recommendations for government agencies, civil society and the international community. [PDF contains 94 pages]

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(PDF contains 4 pages)

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In a small lake, intermittent destratification was installed after several other physico-chemical and physical in-lake therapy measures (phosphorus immobilization, permanent destratification) had been tested without great success. If an aerobic sediment-water interface can be maintained, intermittent destratification removes cyanobacteria and prevents optimal development of other members of the photoautotrophic plankton. During growing seasons, increasing abundances of small-bodied herbivores (Bosmina) and Daphnia may have accounted for relatively low phytoplankton biomass as well. Intermittent destratification is a very fast-working in-lake measure and seems to be applicable even in relatively shallow lakes (< 15 m), in which permanent destratification seems to be risky.

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Despite its recreational and commercial importance, the movement patterns and spawning habitats of winter flounder (Pseudopleuronectes americanus) in the Gulf of Maine are poorly understood. To address these uncertainties, 72 adult winter flounder (27–48 cm) were fitted with acoustic transmitters and tracked by passive telemetry in the southern Gulf of Maine between 2007 and 2009. Two sympatric contingents of adult winter flounder were observed, which exhibited divergent spawning migrations. One contingent remained in coastal waters during the spawning season, while a smaller contingent of winter flounder was observed migrating to estuarine habitats. Estuarine residence times were highly variable, and ranged from 2 to 91 days (mean=28 days). Flounder were nearly absent from the estuary during the fall and winter months and were most abundant in the estuary from late spring to early summer. The observed seasonal movements appeared to be strongly related to water temperature. This is the first study to investigate the seasonal distribution, migration, and spawning behavior of adult winter flounder in the Gulf of Maine by using passive acoustic telemetry. This approach offered valuable insight into the life history of this species in nearshore and estuarine habitats and improved the information available for the conservation and management of this species.

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Using data collected simultaneously from a trawl and a hydrophone, we found that temporal and spatial trends in densities of juvenile Atlantic croaker (Micropogonias undulatus) in the Neuse River estuary in North Carolina can be identified by monitoring their sound production. Multivariate analysis of covariance (MA NCOVA) revealed that catch per unit of effort (CPUE) of Atlantic croaker had a significant relationship with the dependent variables of sound level and peak frequency of Atlantic croaker calls. Tests of between-subject correspondence failed to detect relationships between CPUE and either of the call parameters, but statistical power was low. Williamson’s index of spatial overlap indicated that call detection rate (expressed by a 0–3 calling index) was correlated in time and space with Atlantic croaker CPUE. The correspondence between acoustic parameters and trawl catch rates varied by month and by habitat. In general, the calling index had a higher degree of overlap with this species’ density than did the received sound level of their calls. Classification and regression tree analysis identified calling index as the strongest correlate of CPUE. Passive acoustics has the potential to be an inexpensive means of identifying spatial and temporal trends in abundance for soniferous fish species.

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Rockfish (Sebastes spp.) biomass is difficult to assess with standard bottom trawl or acoustic surveys because of their propensity to aggregate near the seafloor in highrelief areas that are inaccessible to sampling by trawling. We compared the ability of a remotely operated vehicle (ROV), a modified bottom trawl, and a stereo drop camera system (SDC) to identify rockfish species and estimate their size composition. The ability to discriminate species was highest for the bottom trawl and lowest for the SDC. Mean lengths and size distributions varied among the gear types, although a larger number of length measurements could be collected with the bottom trawl and SDC than with the ROV. Dusky (S. variabilis), harlequin (S. variegatus), and northern rockfish (S. polyspinis), and Pacific ocean perch (S. alutus) were the species observed in greatest abundance. Only dusky and northern rockfish regularly occurred in trawlable areas, whereas these two species and many more occurred in untrawlable areas. The SDC was able to resolve the height of fish off the seafloor, and some of the rockfish species were observed only near the seafloor in the acoustic dead zone. This finding is important, in that fish found exclusively in the acoustic dead zone cannot be assessed acoustically. For these species, methods such as bottom trawls, long-lines, or optical surveys using line transect or area swept methods will be the only adequate means to estimate the abundance of these fishes. Our results suggest that the selection of appropriate methods for verifying targets will depend on the habitat types and species complexes to be examined.

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Rockfishes (Sebastes spp.) are an important component of North Pacific marine ecosystems and commercial fisheries. Because the rocky, high-relief substrate that rockfishes often inhabit is inaccessible to standard survey trawls, population abundance assessments for many rockfish species are difficult. As part of a large study to classify substrate and compare complementary sampling tools, we investigated the feasibility of using an acoustic survey in conjunction with a lowered stereo-video camera, a remotely operated vehicle, and a modified bottom trawl to estimate rockfish biomass in untrawlable habitat. The Snakehead Bank south of Kodiak Island, Alaska, was surveyed repeatedly over 4 days and nights. Dusky rockfish (S. variabilis), northern rockfish (S. polyspinis), and harlequin rockfish (S. variegatus) were the most abundant species observed on the bank. Backscatter attributed to rockfish were collected primarily near the seafloor at a mean height off the bottom of 1.5 m. Total rockfish backscatter and the height of backscatter off the bottom did not differ among survey passes or between night and day. Biomass estimates for the 41 square nautical-mile area surveyed on this small, predominantly untrawlable bank were 2350 metric tons (t) of dusky rockfish, 331 t of northern rockfish, and 137 t of harlequin rockfish. These biomass estimates are 5–60 times the density estimated for these rockfish species by a regularly conducted bottom trawl survey covering the bank and the surrounding shelf. This finding shows that bottom trawl surveys can underestimate the abundance of rockfishes in untrawlable areas and, therefore, may underestimate overall population abundance for these species.

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Predicting and under-standing the dynamics of a population requires knowledge of vital rates such as survival, growth, and reproduction. However, these variables are influenced by individual behavior, and when managing exploited populations, it is now generally realized that knowledge of a species’ behavior and life history strategies is required. However, predicting and understanding a response to novel conditions—such as increased fishing-induced mortality, changes in environmental conditions, or specific management strategies—also require knowing the endogenous or exogenous cues that induce phenotypic changes and knowing whether these behaviors and life history patterns are plastic. Although a wide variety of patterns of sex change have been observed in the wild, it is not known how the specific sex-change rule and cues that induce sex change affect stock dynamics. Using an individual based model, we examined the effect of the sex-change rule on the predicted stock dynamics, the effect of mating group size, and the performance of traditional spawning-per-recruit (SPR) measures in a protogynous stock. We considered four different patterns of sex change in which the probability of sex change is determined by 1) the absolute size of the individual, 2) the relative length of individuals at the mating site, 3) the frequency of smaller individuals at the mating site, and 4) expected reproductive success. All four pat-terns of sex change have distinct stock dynamics. Although each sex-change rule leads to the prediction that the stock will be sensitive to the size-selective fishing pattern and may crash if too many reproductive size classes are fished, the performance of traditional spawning-per-recruit measures, the fishing pattern that leads to the greatest yield, and the effect of mating group size all differ distinctly for the four sex-change rules. These results indicate that the management of individual species requires knowledge of whether sex change occurs, as well as an understanding of the endogenous or exogenous cues that induce sex change.

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The fishery for deepwater precious corals in the Hawaiian Islands has experienced an on-and-off history for almost 40 years. In spite of this, research, driven primarily by the precious coral jewelry industry, remains active. In this paper, the results of deepwater surveys in 2000 and 2001 are reported. In summary, a new bed on the summit of Cross Seamount is described and revised estimates of MSY’s for pink coral, Corallium secundum; red coral, Corallium regale; and gold coral, Ger ardia sp., in the two known beds off Makapuu, Oahu, and Keahole Point, Hawaii, in the main Hawaiian Islands, are presented. The population dynamics of each species is described, as well as their ecological limits on Hawaii’s deep reefs, island shelves, and seamounts. The local supply of precious coral in the main Hawaiian Islands is sufficient to support the local industry, but cost/ benefits of selective harvest requirements and weather constraints limit profitability of the fish

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Bycatch management measures instituted for groundfish fisheries of the eastern Bering Sea have focused on reducing the incidental capture and injury of species traditionally harvested by other fisheries. These species include king crab, Paralithodes and Lithodes spp.; Tanner crab, Chionoecetes spp.; Pacific herring, Clupea harengus pallasi; Pacific halibut, Hippoglossus stenolepis; and Pacific salmon and steelhead trout, Oncorhynchus spp. Collectively, these species are called "prohibited species," as they cannot be retained as bycatch in groundfish fisheries and must be discarded with a minimum of injury.

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This is the final presentation from the Moston Brook Evidence and Measures project which ran from September 2012 to March 2013. Moston Brook water body is part of the River Irwell Pilot Catchment and the objective of the project was to devise reliable measures (actions) which were based on existing evidence and that could be implemented in years 2 and 3 by the Environment Agency and its partner to help meet Water Framework Directive (WDF) requirements and community aspirations. The presentation summarises the main suspected causes of WDF failure, the evidence for this, the main causes for failure in the sub-catchments resulting from the evidence found, and identifies measures to carry out, which will address the WDF failures and improve the quality of the water. This presentation can be used to inform others on how to improve the water quality of Moston Brook, and also to support other similar initiatives.

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Through consultations with key fisheries-based stakeholders in four States of India, this study attempts to assess perceptions of fishing communities about the impact of climate change on their lives and livelihoods. It also evaluates the traditional knowledge, institutions and practices of fishing communities that are relevant to climate-change preparedness. The study identifies adaptation and mitigation measures that may need to be adopted by fishing communities and the State in relation to climate change. Based on this overall analysis, the study proposes measures to protect the lives and livelihoods of small-scale fishing communities in the context of climate-change policies and programmes at different levels. This study will be useful for researchers, policymakers, students and anyone interested in climate change and its potential effects on the lives and livelihoods of small-scale fishing communities.