Auswahl der wissenschaftlichen Literatur zum Thema „Marine fishes – North Sea – Identification“

Samples of walleye pollock (Theragra chalcogramma) from the North Pacific Ocean and Bering Sea were screened for variation at the pantophysin (PanI) locus. Global genetic differentiation across samples (FST = 0.038) was considerably greater than reported in previous population studies using allozymes, mtDNA, or microsatellite loci and significantly greater than FST distributions of neutral loci simulated over a large range of locus heterozygosity. PanI allele frequencies varied over a broad latitudinal gradient and were correlated with estimated mean surface temperatures, resulting in the greatest levels of genetic divergence between the northern Bering Sea and the southernmost locations in the temperate Pacific Ocean (Puget Sound, Japan). The discordance between estimates of population differentiation estimated from PanI and other neutral marker classes, both in magnitude and in geographic patterns, could arise from temperature-mediated effects of natural selection over broad geographic scales. Our empirical results suggest that loci subject to directional selection may prove to be useful markers for stock identification in weakly structured marine fishes.

As part of its policy, Mediterranean Marine Science started from 2014 to publish a new series of collective article with fisheries-related data from the Mediterranean Sea. In this first collective article we present length frequencies and weight-length relationships for the northern brown shrimp Farfantepenaeus aztecus in the eastern Mediterranean, length-weight relationships for 10 fish species in the North Aegean Sea, the feeding habits for 11 sparid fishes in the North Aegean Sea, a review of the existing literature on the feeding and reproduction of common carp Cyprinus carpio in Anatolia (Turkey) and mouth dimensions and the relationships between mouth area and length for seven freshwater fishes from Lake Volvi (Northern Greece).

Elucidating the relative roles of dispersal and retention of juvenile stages is an important issue for understanding population structure and evolution in marine organisms. We investigated the genetic population structure of juvenile Atlantic cod (Gadus morhua) within the transition zone between the North Sea and the Baltic Sea, employing nine microsatellite loci, and compared our data with adult cod data from the same area. Small but statistically significant overall differentiation (Fst = 0.003) was found among juvenile samples. Samples of juveniles grouped genetically with adult samples from the same geographical regions. Individual admixture analysis of a large sample of juveniles taken within the transition zone showed that the patterns of genetic differentiation could not be explained by mixing of pure North Sea and Baltic Sea individuals. Instead, the high number of juveniles with intermediate genotypes was compatible with a scenario of exclusive local (transition zone) origin. The results support the hypothesis that population structure in marine fishes is maintained by the retention of juveniles.

Abstract. Connectivity and climate control fish distribution today as well as in the geological past. We present here the Aquitanian (early Miocene) marine fish of the Mesohellenic Basin, a restricted basin at the border between the proto-Mediterranean and Paratethyan seas. Based on fish otoliths, we were able to identify 19 species from 17 genera, including two new species: Ariosoma mesohellenica and Gnathophis elongatus. This fish assemblage, in conjunction with the accompanying molluscan assemblage, indicates a variable shelf paleoenvironment with easy access to the open ocean. Although available data on the Indo-Pacific fishes of the early Miocene are very limited, the fish fauna of the Mesohellenic Basin has many elements in common with the North Sea, the NE Atlantic, and the Paratethys.

Climate warming generally induces poleward range expansions and equatorward range contractions of species’ environmental niches on a global scale. Here, we examined the direction and magnitude of species biomass centroid geographic shifts in relation to temperature and depth for 83 fish species in 9,522 standardised research trawls from the North Sea (1998–2020) to the Norwegian (2000–2020) and Barents Sea (2004–2020). We detected an overall significant northward shift of the marine fish community biomass in the North Sea, and individual species northward shifts in the Barents and North Seas, in 20% and 25% of the species’ biomass centroids in each respective region. We did not detect overall community shifts in the Norwegian Sea, where two species (8%) shifted in each direction (northwards and southwards). Among 9 biological traits, species biogeographic assignation, preferred temperature, age at maturity and maximum depth were significant explanatory variables for species latitudinal shifts in some of the study areas, and Arctic species shifted significantly faster than boreal species in the Barents Sea. Overall, our results suggest a strong influence of other factors, such as biological interactions, in determining several species’ recent geographic shifts.

AbstractAnalysis of offshore data at scales varing from macroscopic to kilometric suggest the former presence of permafrost in the North Sea. However due to the nature of marine data, the techniques used in recognizing features due to former permafrost differ from that used on land. The evidence can also occur in forms unique to the marine field. Awareness of the former existence of permafrost in the North Sea will aid geological assessment of offshore site investigations.

Introduction: The family Carapidae includes about 40 species of marine fishes distributed in coastal habitats worldwide. The family includes some free-living species, however, most of them are found as commensal inquilines or parasites of marine invertebrates, including several echinoderm species. In the Eastern Tropical Pacific, the biology and host use of the representatives of the Carapidae is relatively poorly known. Objective: The present study reports the occurrence of the Star pearlfish Carapus mourlani within three previously unknown hosts in the region: the sea stars Nidorellia armata, Phataria unifascialis, and the sea cucumber Stichopus horrens. Some ecological implications and considerations regarding such symbiotic relationships are raised and discussed. Additional morphometric and meristic data for the fish and the echinoderms are also provided and discussed. Methods: Echinoderms were collected, from 25 localities along the North Pacific coast of Costa Rica, and were carefully examined searching for commensal/parasitic fishes. Echinoderms and fishes were identified and characterized in accordance with the specialized literature. Results: A total of 497 echinoderms, including about 60 species, were collected and examined. Commensal/parasitic fish (a single species represented by 13 specimens) were found in three echinoderm specimens/species. Conclusions: The list of echinoderm hosts for this carapid fish, through its whole distribution range, rises to 12 species (six sea stars and six sea cucumbers) and that could be a consequence of its wide geographic distribution, its generalist feeding habits and opportunistic commensal behavior.

In the eastern North Atlantic, declines in the volume of Atlantic Puffin (Fratercula arctica (Linnaeus, 1758)) eggs have been associated with shifts in the marine ecosystem, such as changes in the abundance of forage fishes and increasing sea-surface temperatures. In the western North Atlantic, where similar shifts in oceanographic conditions and changes in the abundance of forage fishes have presumably occurred, trends in the volume of Atlantic Puffin eggs remain unknown. In this study, we investigate Atlantic Puffin egg volume in the western North Atlantic. We compiled 140 years (1877–2016) of egg volume measurements (n = 1805) and used general additive mixed-effects models to investigate temporal trends and regional variation. Our findings indicate that Atlantic Puffin egg volume differs regionally but has remained unchanged temporally in the western North Atlantic since at least the 1980s.

Improving the knowledge of trophodynamics in coastal marine ecosystems is important for fisheries management. The present study was designed to assess the influence of Danube River inputs on Romanian coastal marine food webs of the European sprat (Sprattus sprattus), the European anchovy (Engraulis encrasicholus) and the horse mackerel (Trachurus mediterraneus). Gut content analyses coupled with carbon and nitrogen stable isotope analyses described food web variations with fish size, season and distance from the Danube delta. Sprats fed on zooplankton, horse mackerel fed on polychaetes and small fish, and anchovies had an intermediate diet. The δ13C and δ15N ratios and mean trophic levels increased from sprats to anchovies and then to horse mackerel. Season strongly influenced the δ15N values of the three fishes, with lower values in spring than in autumn linked to higher Danube inputs into coastal waters in spring during the flooding period. Fish condition was related to diet and environmental factors, with higher conditions recorded in the north area in autumn and in the south area in spring. Danube River inputs influenced the diet, stable isotope ratios and condition of the main commercial pelagic migratory fishes of the north-western Black Sea.

The North Sea has warmed in recent years and there is an ongoing debate into how this is affecting the distribution of fishes and other marine organisms. Of particular interest is the commercially important Atlantic cod ( Gadus morhua L.), which has declined sharply in abundance in the North Sea over the past 20 years. Observations of the temperature experienced by 129 individual cod throughout the North Sea were made during a large-scale electronic tagging programme conducted between 1999 and 2005. We asked whether individual cod fully occupied the thermal habitat available to them. To this end, we compared the temperature experience of cod with independently measured contemporaneous sea-bottom temperature data. The majority of cod experienced a warmer fraction of the sea than was potentially available to them. By summer, most of the individuals in the south experienced temperatures considered superoptimal for growth. Cooler waters were within the reach of the cod and a small number of individuals migrated to areas that allowed them to experience lower temperatures, indicating that the cod had the capacity to find cooler water. Most did not, however, suggesting that the changing thermal regime of the North Sea is not yet causing adult cod to move to cooler waters.

The Deepwater Horizon Oil Spill (DWH) released about 4.4 million barrels of crude oil into the Gulf of Mexico (GOM), making it one of the largest oil spills in U.S. history. Additionally, the depth of the spill (i.e., 1500 meters) created a unique research opportunity because most oil spills occur at the surface and affect coastal rather than deepwater habitats. Polycyclic aromatic hydrocarbons (PAHs) are the most toxic components of oil, and are often the focus of oil exposure studies. PAHs are quickly metabolized by vertebrates; therefore, indicators of biological responses to PAH exposure (PAH “biomarkers”) such as the levels of PAH detoxification enzymes and the resulting metabolites are commonly used to examine oil exposure. This study measured multiple PAH biomarkers including hepatic activity of the PAH detoxification enzymes cytochrome P4501a1 (CYP1A) and glutathione-S-transferase (GST), as well as biliary PAH metabolites in deep sea sharks and bony fishes from areas affected by the Deepwater Horizon Oil Spill. Samples were collected from 2011-2013 from seven species of sharks, with special focus on the four most abundant deep sea species: Centrophorus niakang, Centrophorus cf granulosus, Squalus cubensis and Squalus cf mitsikurii. Overall enzyme activity was low in these sharks, yet it was higher in oiled sites compared to reference locations. Additionally some species showed declining CYP1A activity since the time of the oil spill, suggesting exposure to CYP-inducing compounds during the beginning of the survey period. Last, PAHs of a petrogenic nature were more abundant in oiled sites compared to reference locations. Overall, this project provides the much need biomarker data for sharks as well as insight on exposure and metabolism of PAHs in deep sea sharks after the DWH.

<em>Abstract</em>.-In many areas of the North Atlantic, populations of Atlantic salmon <em>Salmo salar </em>are now either in a state of decline or extirpated such that concern over the continued survival of the species has been given more attention in recent years despite large reductions in directed ocean fisheries. Previous investigations have established linkages between ocean climate conditions and variability in abundance or survival. However, one avenue not previously explored considers whether changes in marine food webs owing to ever increasing and unsustainable levels of exploitation on many marine species-the so-called "fishing down marine food webs" hypothesis-could influence survival and abundance of salmon as a result of shifts in trophic position or changes in energy flows. Since Atlantic salmon are opportunistic feeders during the marine life history phase, the species lends itself well to studies associated with marine environmental conditions and food web interactions. Here, we examine long-term variability in the trophic ecology of Atlantic salmon using analyses of stable isotope signatures of carbon and nitrogen (?¹³C and ?¹⁵N). Signatures were extracted from the marine growth portion of scales of maiden one-sea-winter fish. Data were obtained from nine Canadian and one north European river (Teno) covering periods extending over three to four decades. Significant differences in ?¹³C and ?¹⁵N signatures were found to exist among rivers, as well as among years within rivers. Trends over time in either ?¹³C or ?¹⁵N signatures were evident in only a few situations, thus providing little evidence of substantive changes in the trophic ecology of salmon in the North Atlantic. In addition, isotopic signatures were largely invariant in relation to variations in abundance or to various environmental measures characterizing ocean climate conditions in the North Atlantic.

<em>Abstract</em>.-The sea lamprey <em>Petromyzon marinus </em>is a widely distributed anadromous species spawning in coastal rivers and streams throughout the north Atlantic basin. In this paper, we review aspects of sea lamprey migration and ecology that relate to the transport of nutrients and materials to and from freshwater ecosystems and provide an example of a long-term study of a native wild population. Several aspects of lamprey life history (rapid growth in marine phase, many adults spawn in upper reaches of small oligotrophic rivers, all adults die after spawning) suggest that anadromous sea lampreys contribute marine-derived nutrients and materials (MDNM) to freshwater ecosystems. We used long-term (20 years) data on spawner abundance, along with literature-derived concentration values, to estimate the import of nutrients and materials to a spawning reach of the Fort River, a tributary of the Connecticut River in western Massachusetts, USA. Sea lamprey imported as much as 0.26 g of P per square meter of stream, as much as of 20% of the total annual P loading to a similar system where a full P budget has been developed. While the MDNM contribution of sea lamprey may be substantial, other aspects of their life history and habitat use may limit the overall magnitude and direction of lamprey influence on freshwater ecosystems. Spawning requirement for rocky substrate within a narrow size range may limit import at the watershed scale. In addition, marine survival rates of less than ~1% will result in a net export of nutrients and materials via out-migrating juveniles (transformers). While there is currently no information on survival rates in wild anadromous populations, the tight link between adult survival and prey/host fish populations observed in landlocked Great Lakes systems suggests that the ecological role of sea lamprey may be strongly related to the abundance of coastal marine fishes. Further research on adult survival, juvenile dispersal and distribution, and the paths of nutrient and material uptake in spawning streams are necessary to more fully evaluate the role of anadromous sea lamprey in the transport of MDNM.

<em>Abstract</em>.- Juvenile inanga <em>Galaxias maculatus </em>are the main species in the New Zealand whitebait fishery. Whitebait were sampled throughout the spring fishing season (August-November 2002) as they entered the mouths of two New Zealand rivers, one in the North Island and the other more than 500 km south in the South Island. Fish length, date of arrival at the river mouth, and the number of daily growth rings in otoliths were used to determine age, hatch date, and mean growth rate at sea. Backdating indicated that whitebait hatched between mid-March and late July 2002, spent 104-168 d at sea, and experienced overall growth rates ranging from 0.24 to 0.41 mm/d. Mean length on return to the river mouth ranged from 45 to 55 mm total length and varied among months as well as between rivers. The duration of the oceanic rearing period (in days) was inversely related to growth rate, implying that the time of return to freshwater is endogenously determined. However, average size at river entry was larger for the South Island than for the North Island fish because, on average, the South Island fish remained at sea for a further 10 d. A longer journey from marine feeding grounds back to the coast rather than a delay at the river mouth before entry would account for this difference, but colder oceanic waters in the south may also play a role.

<em>Abstract</em>.-Several coregonid species in northern latitudes exhibit diadromous behavior and may share river/lake systems with conspecifics who are freshwater residents. Although both life history strategies have been reported in a variety of systems, little information on the extent and variability in diadromous behavior both within and among populations exists. We addressed this issue using inconnu <em>Stenodus leucichthys </em>from the Mackenzie River drainage (Northwest Territories, Canada) as a model. At the extremes of their distribution within this system, inconnu have been characterized by alternative life history strategies. Those in the north exhibit diadromous behavior, while those in the south demonstrate life history closure within the upper reaches of the system (i.e., freshwater residency). We examined the otolith strontium profiles of inconnu collected from 12 regions throughout the Mackenzie watershed to (1) determine the geographical range over which diadromy occurs in this system, (2) characterize the variability in diadromous behavior within and among populations, and (3) identify physical/ environmental factors that may influence choice between a diadromous or freshwater life history. Our results demonstrate that the degree of diadromy within populations of inconnu tends to gradually decrease with distance from marine waters, rather than showing an abrupt transition from diadromy to freshwater residency. We conclude that distance from a marine food source plays an important role in determining whether fish remain in freshwater or migrate to the sea to feed. Within diadromous populations of inconnu, there is a substantial level of flexibility in the extent and frequency of marine migration by individuals.

<em>Abstract</em>.-We review the current understanding of major pathways, mechanisms, and consequences of salmon-borne marine-derived nutrients (MDN) in estuarine, freshwater, and riparian ecosystems. Semelparous Pacific salmon <em>Oncorhynchus </em>spp. acquire most of their body mass while at sea before returning to spawn and die in natal streams. The annual spawning migrations transport substantial quantities of MDN from the fertile North Pacific Ocean to relatively nutrient-poor coastal freshwater and terrestrial ecosystems. People have been long aware of the importance of salmon-borne MDN for the productivity of freshwater ecosystems in western North America, and the rapidly increasing knowledge base supports this notion. Nevertheless, many details associated with nutrient pathways, cycling processes, and the ecosystem-scale consequences of MDN transfer remain to be elucidated. The collective data suggest that freshwater portions of the salmon production system, as well as the dynamics of local terrestrial plant and animal communities, are intimately linked to MDN in complex ways. At the same time, the ecological importance of MDN, relative to other major nutrient sources, is temporally and spatially dependent and influenced by the life histories and abundances of salmonid stocks. Although interactions among climate cycles, salmon, riparian vegetation, predators, and MDN flowpaths and feedbacks are complex, they also form a wonderfully integrated ecological system with a high degree of resilience and productivity. Understanding this complex system and its inherent temporal and spatial variability requires a holistic scientific perspective that values important interactions among the salmonid life cycle, the physical setting, and the numerous linkages to other ecosystem components.

<em><strong>Abstract. </strong></em>“Living substrate” has been identified as an important marine habitat and is susceptible to impacts from fishing activities. In Alaskan waters of the North Pacific and Bering Sea, little is known about the distribution of deepwater living substrate such as sponges (phylum Porifera), sea anemones (order Actiniaria), sea whips and sea pens (order Pennatulacea), ascidians (class Ascidiacea), and bryozoans (phylum Ectoprocta). Based on 26 years of survey data (mostly from catches in bottom trawls collected between 1975 and 2000), we created living substrate distribution maps. In general, the five groups of living substrate were observed in varying densities along the continental shelf and upper continental slope. Catch per unit effort (CPUE) of sponges was greatest along the Aleutian Islands, while CPUEs of ascidians and bryozoans were greatest in the Bering Sea. Large CPUEs of sea anemones, sea pens, and sea whips were observed in both the Bering Sea and the Gulf of Alaska. Broad-scale species associations between living substrate and commercially important fishes and crabs were also identified. Flatfish (Bothidae and Pleuronectidae) were most commonly associated with ascidians and bryozoans; gadids (Gadidae; also known as cods) with sea anemones, sea pens, and sea whips; rockfish (<em>Sebastes </em>spp. and shortspine thornyhead <em>Sebastolobus alascanus</em>) and Atka mackerel <em>Pleurogrammus monopterygius </em>with sponges; crabs (<em>Chionoecetes </em>spp., <em>Paralithodes </em>spp., <em>Lithodes </em>spp., Dungeness crab <em>Cancer magister</em>, and hair crab <em>Erimacrus isenbeckii</em>) with ascidians; and other commercial fish species (sablefish <em>Anoplopoma fimbria</em>, Hexagrammidae, and Rajidae) with sea pens and sea whips. These data should provide resource managers with insight into living substrate distribution and relationships among benthic community organisms and, ultimately, with future in-depth studies, may aid in determining specific areas for habitat protection and facilitate management practices that minimize fishery impacts to living substrate.

Objective The objective is to showcase the Abu Ali facility's commitment to protecting and preserving the Abu Ali biodiversity ecosystem. The project demonstrates a modern sustainable, circular, innovative and systemic approach to target the biodiversity threats in multi-dimensional aspects and transform these threats into opportunities to improve the island's ecosystem. The island is important to Aramco's upstream operations because it houses an oil and gas production facility. The organization has determined its environmental goals from the corporate policies and vision to be as follows. Contribute to reaching the company's and the kingdom's vision for being a net zero-carbon operating facility by 2050 and 2060, respectively, by reducing and offsetting greenhouse gases' impact on climate. Support the Saudi Green Initiative by planting mangroves and trees in the Abu Ali Island and seeking for sourcing out the mangrove seeds to other entities. Align and adapt with carbon circular economy (CCE) approaches in reusing/repairing/recycling wasted materials and resources turning them into valuable products. Protect, preserve and enhance the Abu Ali biodiversity area to create an integrated ecosystem for wildlife, marine life, and birds. Be recognized at the corporate, nationally, and internationally as a role model in environmental protection stewardship. Background North of Jubail, a city in the Eastern Province of the Kingdom of Saudi Arabia, close to a large offshore oil field, sits Abu Ali Island. There are two large islands in the archipelago which are potentially preservational. The larger one is Abu Ali Island located to the north and the southern one is called Al Batinah Island. Abu Ali Island is a unique isolated island with one of the most diversified habitats in the Arabian Gulf, a home for a variety of creatures, and Aramco's oil and gas operational area. Aramco has designated Abu Ali Island as the country's first and biggest biodiversity stewardship island. The island is a sabkha semi-dry grassland. The coral reefs that encircle Abu Ali Island were formed naturally, making it an excellent habitat for marine life. The island's ecological and biological systems benefit from the variety of marine life. Birds nest on the island, turtles lay eggs, and foxes hunt for food. Abu Ali Island is on birds' migratory paths, and the island has become a resting area during migratory seasons. Furthermore, Abu Ali Island has been a fishing harbor for local fishermen for decades. Wildlife Habitat Mammals, reptiles, and rodents are just a few of the many biological species found on Abu Ali Island. Numerous other species, including the Cerastes Gasperettii/Arabian horned viper "Um Jounab" and the Arabian Red Fox, were also commonly observed on the island. The island is covered with vegetation, including native plants, cultivated trees, and herbs such as Ziziphus spina-christi "Sidir," Rhanterium epapposum "Arfaj," and Zygophyllum qatarense. Migratory Birds The island is situated in one of the main flyways of migratory birds that travel seasonally from Siberia & Eastern Europe to Africa. The migratory birds settle down for a couple of days/weeks to take a rest and food supply, then continue their long journey. The following migratory bird species have been spotted at Abu Ali Island: Black-necked Grebe, Great Crested Grebe, Black Kite, Slender-billed Gull, Greater Flamingo, Western Reef-egret, Lesser Crested Tern, White-cheeked Tern, Saunders's Tern, Little Tern, Grey Plover, Lesser Sandplover, Greater Sandplover, Kentish Plover, Bar-tailed Godwit, Whimbrel, Eurasian Curlew, Dunlin, Terek Sandpiper, Common Redshank, Common Greenshank, Ruddy Turnstone, Eurasian Oystercatcher, Crab-plover and Osprey. Marine Life Abu Ali Island is a territory of a critically endangered creature, the Hawksbill sea turtle. The turtles travel to various sites in the Arabian Gulf and lay their eggs on an island like Abu Ali Island during the year's roosting season. Besides that, coral reefs, seagrass, and mangroves thrive around Abu Ali Island creating attractive habitats for fishes and other organisms to reproduce and enrich marine life.

The historical legacy of the TITANIC defies a brief manuscript of 20- plus pages. Much better, and more detailed work has been done to give the subject a “modern” context, notably by the United States Coast Guard in the Summer 2012 issue of Proceedings of the Marine Safety and Security Council, vol.69, no. 2, from which the following remarks draw heavily. The night of April 14, 1912 – the famous “night to remember,” chosen by Walter Lord as the title of his excellent history – presents us with many questions that will probably never be answered. Most of these are technical: the “what ifs” that, in one form or another, haunt us after, but usually not before, a disaster at sea. The importance of safety at sea is shown by the pictures available since 1985, showing the broken fragments of wreckage lying on the ocean floor south of Cape Race. Since the wreckage was located, we can see the pairs of empty shoes and boots that mark where human remains once lay. The TITANIC facts are familiar: at 11:40 P.M. on April 14, 1912, she collided with an iceberg. Two hours and 40 minutes later, the pride of the White Star Line began her two-mile plunge to the bottom of the North Atlantic. Of the 2,224 passengers and crew aboard, only 710 survived. While there have been sea disasters that produced greater loss of life, the sinking of TITANIC is probably the most famous and far-reaching maritime disaster in history. While the loss of TITANIC has been described as “perhaps the most documented and least commonly understood marine casualty in maritime history”, a positive result of the TITANIC disaster, and of course many other tragedies at sea that have occurred since, has been to establish a formal protocol of goals and procedures for analysis and investigation. These goals, from the point of view of the investigator/flag state, other governments, the International Maritime Organization (IMO), and other regulators, is the identification of unsafe conditions, in order to identify them in advance of future disasters. Today, responsible regimes charged with administration of the safety of life at sea are said to follow a philosophy of prevention first and, then, response. The 1985 discovery of the wreck of the TITANIC sparked a new round of forensic investigation. The bow section was found largely intact with the stern section in hundreds of pieces approximately 2,000 feet away. The realization that TITANIC’s hull had broken at some point during the sinking added a new understanding of the already famous disaster. The discovery of the wreck also provided new forensic evidence in the form of recovered artifacts and detailed surveys. It was these new clues and advances in computer-driven engineering tools that gave rise to a revision of previously held beliefs. The significance of the TITANIC, and the events that led to such a large loss of life, remain with us today.

Abstract Subsea conductors are the foundational elements of offshore drilling operations, serving a dual purpose as both the structural framework and the main conduit for casing installation and wellbore access. These cylindrical structures, often made from robust steel, extend from the seabed to the surface, piercing through the water column to provide a stable, continuous path for the drilling operations and subsequent production activities. As the initial point of contact with the subsea environment, they play a pivotal role in ensuring the structural integrity of the drilling operation and maintaining fluid communication between the subterranean layers and the surface facilities. The environments in which subsea conductors operate are among the most challenging on Earth, characterized by extreme pressures, corrosive saltwater, variable temperatures, and the mechanical stress imposed by dynamic sea conditions. These factors can severely impact the longevity and functionality of the conductors, making their integrity crucial to the safety, environmental stewardship, and efficiency of offshore drilling operations. Any compromise in their integrity—be it through corrosion, physical damage, or blockages—can have far-reaching consequences. These range from operational downtime, costly repairs, and loss of production to more severe outcomes like oil spills, which pose significant environmental hazards, and catastrophic failures, which present grave safety risks to personnel and marine life. Given these stakes, the regular and thorough inspection of subsea conductors is not merely a procedural step but a critical necessity. Advanced inspection techniques, including the use of remotely operated vehicles (ROVs), ultrasonic testing, and magnetic flux leakage methods, are employed to detect anomalies such as cracks, corrosion, or deposits that could impede the flow of hydrocarbons or compromise the conductor’s structural integrity. These inspections are complemented by sophisticated maintenance strategies designed to preemptively address potential issues, thereby avoiding unplanned operational disruptions. Furthermore, the design and installation of subsea conductors demand meticulous planning and execution to ensure they can withstand the operational lifespan of the drilling platform, often several decades. Engineers must account for various factors, including the geological characteristics of the seabed, the anticipated load from the drilling operations, and the environmental forces, to design conductors that are both resilient and compliant with international standards and regulations. The use of a trash cap during offshore drilling operations is an essential practice for safeguarding the integrity of the wellbore and the surrounding marine environment. A trash cap, essentially a protective cover, is placed over the wellbore or the conductor pipe to prevent the ingress of debris, sediment, and other unwanted materials that could compromise the drilling process. This need arises from the potential for various types of refuse, ranging from natural debris carried by ocean currents to remnants of drilling activities, to obstruct the wellbore. Such blockages can lead to operational delays, increased costs, and, in severe cases, the abandonment of the drilling site. Moreover, the trash cap plays a critical role in environmental protection during drilling operations. By preventing pollutants and drilling by-products from escaping into the ocean, it helps mitigate the impact on marine life and water quality. The cap also serves as a barrier against accidental spills of drilling fluids or hydrocarbons, which can have devastating effects on marine ecosystems. In addition to these protective functions, the trash cap facilitates the maintenance and inspection activities essential for the efficient operation of offshore drilling. It allows for a controlled environment in which inspections can be carried out, and maintenance or repair work can be performed without the interference of external conditions. This is particularly important in harsh weather or when dealing with sensitive ecological areas. In summary, subsea conductors are not merely physical structures but critical components that underpin the viability and safety of offshore drilling operations. Their role extends beyond facilitating drilling activities to encompassing the safeguarding of environmental and personnel safety. As such, the integrity of these conduits is paramount, necessitating a regime of rigorous inspection, maintenance, and when necessary, repair, to mitigate the risks associated with their operation in the demanding offshore environment. This comprehensive approach ensures the continued efficiency, safety, and environmental compatibility of offshore drilling ventures, highlighting the sophisticated balance between engineering prowess and environmental responsibility in the pursuit of energy resources. The installation of subsea conductors during offshore drilling operations encompasses a range of complex challenges, stemming from both the harsh marine environment and the intricate engineering requirements of deep-water exploration. One of the foremost difficulties is the precise placement of these conductors on the seabed, which requires sophisticated navigation and positioning technologies to ensure accuracy in depths that can extend to several thousand feet. Environmental conditions such as strong ocean currents, high waves, and unpredictable weather further complicate this task, posing risks to both the equipment and the safety of the personnel involved. Additionally, the structural integrity of subsea conductors must be maintained against the immense pressures and corrosive elements found in deep-sea environments. This necessitates the use of materials and coatings that can withstand such conditions over long periods, alongside innovative design solutions to counteract the physical stresses imposed by the water depth and seabed conditions. The variability of the seabed’s geology also presents a significant challenge, as soft sediments may require different installation techniques compared to more stable rock formations. Another critical issue is the potential for environmental impact, which demands meticulous planning and execution to minimize disturbances to marine ecosystems. The installation process must adhere to stringent environmental regulations and best practices to prevent damage to marine life and habitats. Furthermore, the logistical complexities of transporting and handling the heavy and cumbersome conductor pipes and installation equipment in the open sea cannot be underestimated. This requires not only specialized vessels and machinery but also highly skilled personnel to execute the operations safely and efficiently. Overcoming these challenges requires a multidisciplinary approach that combines advanced technological solutions, detailed environmental assessments, and robust engineering and operational planning. The ability to adapt to the dynamic and demanding conditions of offshore drilling is crucial for the successful installation of subsea conductors, underscoring their critical role in the exploration and production of offshore hydrocarbon resources. This paper delves into the intricacies of a state-of-the-art drop-down camera system, meticulously designed and engineered for the internal inspection of subsea conductors. The emphasis is on the system’s development, from conceptualization through to testing and operational deployment, highlighting its role in preempting operational issues by identifying and removing debris or obstructions within the conductors. The deployment of this technology at the North Safa platform represents a significant advancement in subsea inspection methodologies. GUPCO, a joint venture between the Egyptian General Petroleum Corporation (EGPC) and a Dragon oil which is a leading international oil company, has played a pivotal role in harnessing the potential of the North Safa Oil Field through innovative technologies and sustainable practices. The camera system is equipped with high-resolution imaging capabilities, bolstered by powerful LED lighting to ensure clarity and visibility in the deep-sea environment. A key feature of the system is its flexibility, facilitated by a durable tether that allows the camera to navigate the complex architecture of subsea conductors with precision. This flexibility is critical for the thorough inspection of conductor slots, which can vary widely in design and condition. Operational deployment involves lowering the camera system into the conductor from the platform. A subsea Remotely Operated Vehicle (ROV) plays a pivotal role in guiding the system through the conductor’s slots, a task that requires meticulous control and navigation to avoid damaging the conductor’s internal surfaces. The inspection process is comprehensive, focusing on the identification of potential obstructions, debris, and signs of wear or damage that could compromise the conductor’s integrity. The real-time data transmission capability of the camera system is a significant technological advancement, enabling instant analysis and decision-making. This feature is particularly beneficial for offshore operations where time is of the essence, and rapid responses to potential issues are necessary to prevent downtime or accidents. Results from the system’s deployment on the North Safa platform have been overwhelmingly positive, demonstrating its effectiveness in detecting and eliminating potential threats to conductor integrity. The high-resolution cameras provide detailed imagery of the conductor walls, revealing even the smallest particles or blockages that could pose a risk to drilling operations. This level of detail is crucial for ensuring the safety and efficiency of offshore drilling activities. The implications of this technology extend far beyond the immediate benefits of cleaner and safer conductors. By enhancing the reliability of subsea infrastructure, the camera system contributes to the overall operational efficiency of offshore drilling operations. It represents a proactive approach to maintenance and safety management, reducing the likelihood of unforeseen disruptions and the associated costs. Moreover, the adoption of such sophisticated inspection technologies underscores the offshore industry’s commitment to safety and environmental stewardship. By ensuring the integrity of critical infrastructure, the industry can mitigate the risks of spills and accidents, contributing to the protection of marine ecosystems. In conclusion, the development and deployment of the drop-down camera system for subsea conductor inspection mark a significant technological leap in offshore drilling operations. Its success in the North Safa platform demonstrates the system’s potential for broader industry adoption, offering a viable solution for enhancing the safety and efficiency of subsea drilling activities. The system’s ability to provide detailed, real-time insights into the condition of subsea conductors sets a new standard for operational excellence in the offshore oil and gas industry. As the industry continues to explore and exploit deep-water reserves, the importance of such advanced inspection technologies will only increase, underscoring their role in ensuring the sustainable and safe development of offshore resources.

DIPLANOAGAP: Distribution of Plastics in the North Atlantic Garbage Patch Ponta Delgada (Portugal) – Malaga (Spain) 17.08. – 12.09.2019 The expedition POS 536 is part of a multi-disciplinary research initiative of GEOMAR investigating the origin, transport and fate of plastic debris from estuaries to the oceanic garbage patches. The main focus will be on the vertical transfer of plastic debris from the surface and near-surface waters to the deep sea and on the processes that mediate this transport. The obtained data will help to develop quantitative models that provide information about the level of plastic pollution in the different compartments of the open ocean (surface, water column, seafloor). Furthermore, the effects of plastic debris on marine organisms in the open ocean will be assessed. The cruise will provide data about the: (1) abundance of plastic debris with a minimum size of 100 μm as well as the composition of polymer types in the water column at different depths from the sea surface to the seafloor including the sediment, (2) abundance and composition of plastic debris in organic aggregates (“marine snow”), (3) in pelagic and benthic organisms (invertebrates and fish) and in fecal pellets, (4) abundance and the identity of biofoulers (bacteria, protozoans and metazoans) on the surface of plastic debris from different water depths, (5) identification of chemical compounds (“additives”) in the plastic debris and in water samples.

This map depicts the geomorphology of the Chatham Sound area, British Columbia, and is based on bathymetry and backscatter data from multibeam sonar surveys, complemented by 3.5 kHz subbottom profiler data, grab samples, cores, and bottom photographs. The map encompasses three physiographic areas: 1) the easternmost portion of Dogfish Banks; 2) the north-south oriented Hecate trough; and 3) the maze of channels and inlets east of Hecate trough. The morphological and textural complexity reflects the underlying bedrock, glacial history, a complex pattern of postglacial relative sea-level change, and modern oceanographic processes. Hexactinellid sponge reefs are a significant component of the seafloor mosaic. The criteria for reef identification were positive relief, low backscatter strength, and acoustic transparency.