Study the methods of connecting jacket to the seabed and choosing the best method for Persian Gulf according to soil characteristics

Offshore structures with numerous applications in different environments throughout the world and used at different depths. Due to the expansion of marine industries, including offshore oil industry in Iran , particularly in the Persian Gulf region, in order to more accurately model these structures and to prevent incidents such as the Overturning of the platform serious damage to the South Pars Phase ١٣ was platforms, the use New Technic is essential technologies. One of the methods that are used in the construction of offshore wind turbines, using a pre-pile. In this method, a template is constructed with the dimensions specified in the workshop. After making templates using special vessels for placement in the desired location on the sea bed is carried, then the template is placed on the sea bed, Then, using a hammer for Pile Driving Operation Started Vibration hammer and fit the template of 3 or 4 piles of crushed within this template on the seabed . The next step piling, templates have been removed from the site And Jacket placed on piles. The system was installed on the deck on piles and Consequently Deck Load pile inserted on .It should be noted that the design of these types of platforms, base diameter of the pile diameter independent of the choice as one of the major advantages of this system is. This thesis examines a Template Fixed Platform in the oil Soroush Using the Pre-Piling and the Common Piling systems in the Persian Gulf were studied and the effect of different design compared to the Pre-Piling Platforms Persian Gulf were evaluated. The results suggest that Pre-Piling system compared with conventional systems piling in the Persian Gulf, as a more appropriate model structure and behavior Top Model economic efficiency is selected. It should be noted that all calculations and analyzes were performed using Software Abaqus.

Potential use of offshore marine structures in rebuilding an overfished rockfish species, bocaccio (Sebastes paucispinis)

Although bocaccio (Sebastes paucispinis) was an economically important rockfish species along the west coast of North America, overfishing has reduced the stock to about 7.4% of its former unfished population. In 2003, using a manned research submersible, we conducted fish surveys around eight oil and gas platforms off southern California as part of an assessment of the potential value of these structures as fish habitat. From these surveys, we estimated that there was a minimum of 430,000 juvenile bocaccio at these eight structures. We determined this number to be about 20% of the average number of juvenile bocaccio that survive annually for the geographic range of the species. When these juveniles become adults, they will contribute about one percent (0.8%) of the additional amount of fish needed to rebuild the Pacific Coast population. By comparison, juvenile bocaccio recruitment to nearshore natural nursery grounds, as determined through regional scuba surveys, was low in the same year. This research demonstrates that a relatively small amount of artificial nursery habitat may be quite valuable in rebuilding an overfished species.

Sea Turtle Observations at Explosive Removals of Energy Structures

Observers were placed at offshore sites to monitor and protect sea turtles during explosive removals of oil and gas structures in the Gulf of Mexico off Louisiana and Texas. Data collected during more than 6,500 hours of monitoring at 106 structure removals in 1992 provided information on sea turtle distribution. Eighteen individuals were observed including 10 loggerheads, 2 leatherbacks, 1 hawksbill, and 5 unidentified sea turtles. The observation rate (individuals per monitoring hour) of sea turtles was about 30 times higher during aerial surveys than during day or night suiface surveys.

A short survey of the environment at the dumping site for Santa Cruz Harbor dredging and A study of seaward dipping internal structures in marine ripple marks at Whaler's Cove, California. Annual report, Part 4, August 1972

(PDF contains 76 pages)

Beach monitoring project Sand Key Phase II Beach nourishment program (North Redington Beach and Redington Shores) Post-Nourishment Report Part II Offshore Profiles and Wave Data

This study presents the third post-nourishment survey (January 1989) results for the Sand Key Phase II beach nourishment project carried out in June, 1988. The monitoring program to this beach nourishment project is a joint effort between the University of South Florida and University of Florida. The field surveys include a total of 26 profiles, encompassing approximately 3 miles of shoreline extending from DNR R-96 to R-1ll. The total calculated volume loss of sand in the nourished segment (from R-99G to R-107) between the July 88 and January 89 surveys is 51,113 cubic yards, which is a loss about 9.7 percent of 529,150 cubic yards actually placed in the nourishment project. The total loss of sand computed in the entire survey area is 26,796 cubic yards, which is only 5.1 percent of the sand placed in the nourishment project. It is stressed that a part of these net volume reductions is due to the background erosion and not due to spreading losses induced by the nourishment project. (PDF contains 168 pages.)

Organizational Structures and Strategies For the Hard Clam Aquaculture Industry in Florida

This study provides guidance on statewide organization for the commercial hard clam culture industry in Florida. The study characterizes the structure of and identifies strategies for successful agricultural and aquacultural organizations designed to provide the resources needed to solve current and projected industry problems. Objectives were to 1) characterize the structure of successful and relevant organizations, 2) identify successful revenue generating strategies, 3) provide the hard clam culture industry with options to help facilitate their organizational decisions, and 4) assist clam growers in Florida in developing an umbrella organizational strategy that will meet their future industry needs. (PDF has 60 pages.)

An integrated assessment of the continued spread and potential impacts of the colonial ascidian, Didemnum sp. A, in U.S. waters

Didemnum sp. A is a colonial ascidian or “sea squirt” of unknown geographic origin. Colonies of Didemnum sp. A were first documented in U.S. waters in 1993 at Damariscotta River, Maine and San Francisco Bay, California. An alarming number of colonies have since been found at several locations in New England and along the West Coast of the contiguous continental United States. Originally believed to be restricted to artificial structures in nearshore habitats, such as ports and marinas, colonies of Didemnum sp. A have also been discovered on a gravel-pavement habitat on Georges Bank at depths of 40-65m. The wide distribution of Didemnum sp. A, the presence of colonies on an important offshore fishing ground, and the negative economic impacts that other species of noninidigenous ascidians have had on aquaculture operations have raised concerns about the potential impacts of Didemnum sp. A. We reviewed the available information on the biology and ecology of Didemnum sp. A and potentially closely related species to examine the environmental and socioeconomic factors that may have influenced the introduction, establishment and spread of Didemnum sp. A in U.S. waters, the potential impacts of this colonial ascidian on other organisms, aquaculture, and marine fisheries, and the possibility that it will spread to other U.S. waters. In addition, we present and discuss potential management objectives for minimizing the impacts and spread of Didemnum sp. A. Concern over the potential for Didemnum sp. A to become invasive stems from ecological traits that it shares with other invasive species, including the ability to overgrow benthic organisms, high reproductive and population growth rates, ability to spread by colony fragmentation, tolerance to a wide range of environmental conditions, apparent scarcity of predators, and the ability to survive in human dominated habitats. At relatively small spatial scales, species of Didemnum and other nonindigenous ascidians have been shown to alter the abundance and composition of benthic assemblages. In addition, the Canadian aquaculture industry has reported that heavy infestations of nonindigenous ascidians result in increased handling and processing costs. Offshore fisheries may also suffer where high densities of Didemnum sp. A may alter the access of commercially important fish species to critical spawning grounds, prey items, and refugia. Because colonial ascidian larvae remain viable for only 12–24hrs, the introduction and spread of Didemnum sp. A across large distances is thought to be predominantly human mediated; hull fouling, aquaculture, and ballast water. Recent studies suggest that colony growth rates decline when temperatures exceed 21 ºC for 7 consecutive days. Similarly, water temperatures above 8 to 10 ºC are necessary for colony growth; however, colonies can survive extended periods of time below this temperature threshold as an unidentified overwintering form. A qualitative analysis of monthly mean nearshore water temperatures suggest that new colonies of Didemnum will continue to be found in the Northeast U.S., California Current, and Gulf of Alaska LMEs. In contrast, water temperatures become less favorable for colony establishment in subarctic, subtropical, and tropical areas to the north and south of Didemnum’s current distribution in cool temperate habitats. We recommend that the Aquatic Nuisance Species Task Force serve as the central management authority to coordinate State and Federal management activities. Five objectives for a Didemnum sp. A management and control program focusing on preventing the spread of Didemnum sp. A to new areas and limiting the impacts of existing populations are discussed. Given the difficulty of eradicating large populations of Didemnum sp. A, developing strategies for limiting the access of Didemnum sp. A to transport vectors and locating newly established colonies are emphasized. (PDF contains 70 pages)

The impacts of coastal protection structures in California’s Monterey Bay National Marine Sanctuary

This report outlines the potential impacts of coastal protection structures on the resources of the Monterey Bay National Marine Sanctuary. At least 15 miles of the Sanctuary’s 300-mile shoreline are currently armored with seawalls and riprap revetments. Most of these coastal protection structures are placed above the mean high tide line, the official boundary of the Sanctuary, yet some influences of armoring impinge on the marine realm and on recreational use. In addition, continued sea level rise and accompanying coastal retreat will force many of these structures below the high tide line over time. The Monterey Bay National Marine Sanctuary staff has recognized the significance of coastal armoring, identifying it as a critical issue in the Coastal Armoring Action Plan of the draft Joint Management Plan. This summary is intended to provide general background information for Sanctuary policies on coastal armoring. The impacts discussed include: aesthetic depreciation, beach loss due to placement, access restriction, loss of sand supply from eroding cliffs, passive erosion, and active erosion. In addition, the potential biological impacts are explored. Finally, an appraisal of how differing armor types compare in relation to impacts, expense and engineering is presented. While the literature cited in this report focus predominantly on the California coast, the framework for this discussion could have implications for other actively eroding coastlines. (PDF contains 26 pages.)

Precision of age determination of northern offshore spotted dolphins.

We investigated within- and between-reader precision in estimating age for northern offshore spotted dolphins and possible effects on precision from the sex and age-class of specimens. Age was estimated from patterns of growth layer groups i n the dentine and cementum of the dolphins' teeth. Each specimen was aged at least three times by each of two persons. Two data samples were studied. The first comprised 800 of each sex from animals collected during 1973-78. The second included 45 females collected during 1981. There were significant, generally downward trends through time in the estimates from multiple readings of the 1973-78 data. These trends were slight, and age distributions from last readings and mean estimates per specimen appeared to be homogeneous. The largest factor affecting precision in the 1973-78 data set was between-reader variation. In light of the relatively high within-reader precision (trends considered), the consistent between-reader differences suggest a problem of accuracy rather than precision for this series. Within-reader coefficients of variation averaged approximately 7% and 11%. Pooling the data resulted i n an average coefficient of variation near 16%. Within- and between-reader precision were higher for the 1981 sample, and the data homogeneous over both factors. CVs averaged near 5% and 6% for the two readers. These results point to further refinements in reading the 1981 series. Properties of the 1981 sample may be partly responsible for greater precision: by chance there were proportionately fewer older dolphins included, and preparation and selection criteria were probably more stringent. (PDF contains 35 pages.)

Early postnatal growth of the spotted dolphin, Stenella attenuata, in the offshore Eastern Tropical Pacific.

Estimates of length at birth and early postnatal growth are made for the northern and southern populations of the offshore spotted dolphin in the offshore eastern tropical Pacific. Length at birth is estimated to be 85.4 cm for the northern population and 83.2 cm for the southern population. Analyses of series of monthly distributions of length revealed two cohorts born each year in the northern population, at least in the northern inshore part of its geographic range, but only one cohort born each year in the southern population. Growth curves fitted to the means of the monthly distributions of length gave estimates of length at 1 year of 126.2 and 132.6 cm and length at 2 years of 154.3 and 154.9 cm for the two cohorts in the northern population. and length at 1 year of 127.9 cm for the southern population. A growth curve fitted to lengths and ages (in dental growth layer groups) from the northern population gave estimates of lengths at 1 and 2 years of 123.0 and 143.0 cm, respectively.

Abundance and Distribution of Ichthyoplankton along an Inshore-Offshore Transect in Onslow Bay, North Carolina

The distribution and abundance of ichthyoplankton was investigated from November 1979 to March 1980 along a transect from coastal to continental slope waters in Onslow Bay, North Carolina. Representatives of 66 families were collected; 24 of which were tropical families, a category that also includes families of typically oceanic and deep-sea fishes. Larvae of tropical species were collected in coastal and shelf waters, demonstrating the intrusion of Gulf Stream waters onto the continental shelf. From December through March, frontal waters that separated cold open-shelf surface waters from warm Gulf Stream surface waters were observed. Higher abundances of fish larvae were sometimes, but not consistently, associated with frontal waters. A great diversity of taxa was collected in offshore waters, and densities of larvae were low in coastal waters; low densities were attributed to gear selectivity rather than low larval abundance. Larvae of commercially and recreationally important estuarine-dependent species, especially Leiostomus xanthus and Micropogonias undulatus, were dominant components of the ichthyoplankton. Representatives of the families Bothidae, Clupeidae, Gadidae, Gonostomatidae, Myctophidae, Ophidiidae, and Sparidae were also important components of the ichthyoplankton. Larvae of species representing two strikingly different life history types-mesopelagic and estuarine-dependent frequently cooccurred.(PDF file contains 32 pages.)

Present status and potentials of inshore and offshore pelagic fisheries in the capture and processing industries of Nigeria

Apart from activities of some foreign-based vessels, commercial exploitation of pelagic fishery resources in Nigeria has been limited to inland and inshore waters. Estimated potential for the inshore pelagic fishery is 70,000-90,000 tonnes while the small pelagic resources in the near offshore as well as tuna and tuna-like fishes further offshore have potentials of about 10,000 metric tonnes each. Despite the abundance of tuna within and adjoining the Nigerian EEZ, and its importance in the international market, only foreign-flagged vessels take advantage. In addition, the inshore pelagic fisheries in Nigeria have for long remained underexploited. The most common processing method has remained the age-old traditional smoke-drying, which is inadequate resulting in colossal waste through denaturation and incessant infestations by insects and moulds among other causes. The use of modern smoking techniques coupled with effective distribution systems can undoubtedly reduce waste. However, these are often not within the reach of most artisanal processors. It is proposed that the organised private sector should invest on simple but proven processing equipment such as smoking kilns. The inshore pelagic fish species and other small fishes can sustain cottage canning industries sited in fishing villages/settlements while larger canning factories should be based on offshore resources. Modalities for successful investments are highlighted, while a major consideration is given to joint ventures

Growth of yellowfin tuna, Thunnus albacares, in the Eastern Pacific Ocean based on otolith increments

ENGLISH: The growth of yellowfin tuna in the eastern Pacific is described in terms of several measurements taken from the fish and their otoliths (sagittae). Equations are also developed to predict age from the readily available dimensions of fork length and head length. The data for all of these relationships were obtained from a sample of 196 fish collected during 1977 through 1979 from purse seiners fishing north of the equator and east of 137°W. The fork-length range of the sample was 30-170 cm. The number of increments on a sagitta of each fish was used as a direct estimate of its age in days. The correspondence between increments and days has been validated for yellowfin in the length range of 40-110 cm. Circumstantial evidence indicates that the relationship also applies in the intervals of 0-40 cm and 110-170 cm. This circumstancial evidence was derived from: 1) literature on validated increments during early growth for other species, 2) knowledge that structures assumed to be daily increments on yellowfin otoliths have subsequently been validated in the corresponding zone on bluefin otoliths, and 3) a comparison of the growth curve based on increments to others obtained from length frequency modal analysis. Based on this information the age estimates over the entire size range of sampled fish are believed to be accurate. In addition to the general growth and age-predictive relationships, the major conclusions of the study are that: 1) Sexually dimorphic growth exists in terms of fork length, fish weight and the length of the otolith counting path for the entire data set. Examination of the data for 1977 and 1979 also revealed that the fork-length growth of each sex differed within years. 2) For combined sexes there were significant differences among the fork-length growth curves for yellowfin sampled in different years. 3) Yellowfin caught inshore (within 275 miles of the coast) were heavier than those caught offshore for fork lengths between 30 and 110 cm. The situation was reversed for lengths greater than 110 cm. 4) Back-calculated spawning months were distributed uniformly throughout the year in 1974 and 1977, but in 1975-1976 and 1978 spawning activity was apparently concentrated in the latter half of the year. SPANISH: El crecimiento del atún aleta amarilla en el Pacífico oriental se describe en términos de varias medidas obtenidas de peces y otolitos (sagita). Se formularon también ecuaciones para pronosticar la edad, según las dimensiones fácilmente disponibles de la longitud horquilla y longitud de la cabeza. Los datos de todas estas relaciones fueron obtenidos mediante una muestra de 196 peces recolectados desde 1977hasta 1979, en barcos cerqueros que estaban pescando al norte de la línea ecuatorial y al este de los 137°W. El intervalo de la longitud horquilla de la muestra fue de 30-170 cm. Se empleó el número de incrementos en la sagita de cada pez como un estimado directo de la edad en días. Se ha comprobado la relación entre los incrementos y los días en el intervalo de longitud de 40-110 cm del aleta amarilla. La evidencia circunstancial indica que se aplica también la relación a los intervalos de 0-40 cm y 110-170 cm. Esta evidencia circunstancial se dedujo: 1) de las publicaciones sobre incrementos comprobados de otras especies durante el primer crecimiento, 2) del conocimientoque las estructuras que se supone son incrementos diarios en los otolitos del aleta amarilla han sido comprobadas luego en la parte correspondiente de otolitos del aleta azul y 3) por una comparación de la curva de crecimiento, basada en incrementos relacionados a otras curvas obtenidas según el análisis modal frecuencia-talla. Se cree, basados en esta información, que las estimaciones de la edad sobre toda la amplitud de talla de los peces muestreados, es acertada. Además de la relación del crecimiento general y del pronóstico de la edad, las principales conclusiones de este estudio son: 1) En toda la serie de datos existe el crecimiento sexualmente dimórfico en términos de longitud horquilla, peso del pez y longitud del plano de conteo del otolito. El examen de los datos de 1977 y 1979, revelan también que el crecimiento longitud horquilla de cada sexo es diferente en los años. 2) En los sexos combinados hubo diferencias significativas entre las curvas de crecimiento longitud horquilla del aleta amarilla muestreado en diferentes años. 3) El aleta amarilla capturado cerca a la costa (en las primeras 275 millas) fue más pesado que el capturado en las aguas mar afuera, correspondiente a la longitud horquilla entre 30 y 110 cm. La situación fue inversa para tallas de más de 110 cm. 4) En 1974 y 1977, los meses retrocalculados del desove se distribuyeron uniformemente durante el año, pero en 1975-1976 y 1978, la actividad del desove se concentró aparentemente en el último semestre del año. (PDF contains 62 pages.)

Habitat enhancing marine structures: Creating habitat in urban waters

Although maritime regions support a large portion of the world’s human population, their value as habitat for other species is overlooked. Urban structures that are built in the marine environment are not designed or managed for the habitat they provide, and are built without considering the communities of marine organisms that could colonize them (Clynick et al., 2008). However, the urban waterfront may be capable of supporting a significant proportion of regional aquatic biodiversity (Duffy-Anderson et al., 2003). While urban shorelines will never return to their original condition, some scientists think that the habitat quality of urban waterfronts could be significantly improved through further research and some design modifications, and that many opportunities exist to make these modifications (Russel et al., 1983, Goff, 2008). Habitat enhancing marine structures (or HEMS) are a potentially promising approach to address the impact of cities on marine organisms including habitat fragmentation and degradation. HEMS are a type of habitat improvement project that are ecologically engineered to improve the habitat quality of urban marine structures such as bulkheads and docks for marine organisms. More specifically, HEMS attempt to improve or enhance the physical habitat that organisms depend on for survival in the inter- and sub-tidal waterfronts of densely populated areas. HEMS projects are targeted at areas where human-made structures cannot be significantly altered or removed. While these techniques can be used in suburban or rural areas restoration or removal is preferred in these settings, and HEMS are resorted to only if removal of the human-made structure is not an option. Recent research supports the use of HEMS projects. Researchers have examined the communities found on urban structures including docks, bulkheads, and breakwaters. Complete community shifts have been observed where the natural shoreline was sandy, silty, or muddy. There is also evidence of declines in community composition, ecosystem functioning, and increases in non-native species abundances in assemblages on urban marine structures. Researchers have identified two key differences between these substrates including the slope (seawalls are vertical; rocky shores contain multiple slopes) and microhabitat availability (seawalls have very little; rocky shores contain many different types). In response, researchers have suggested designing and building seawalls with gentler slopes or a combination of horizontal and vertical surfaces. Researchers have also suggested incorporating microhabitat, including cavities designed to retain water during low tide, crevices, and other analogous features (Chapman, 2003; Moreira et al., 2006) (PDF contains 4 pages)

Einfluß von Anlagen der Offshore-Industrie auf die Fischerei in der Nordsee

From the beginning of the oil and gas exploration in the North Sea the impact of offshore installations, especially pipelines, on the fishery has been thoroughly discussed and investigated. Since fishing activities in the vicinity of pipelines are not prohibited, special precautions have to be taken to prevent towed fishing gear from being fouled by a pipeline. Until now all recommendations for the installation of pipelines are based on the results of tests with trawls crossing one pipeline. New problems will arise if parallel pipelines are installed as planned in the near future.