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Quantification of bottom trawl fishing damage to ancient shipwreck sites
... On the other hand, bottom trawling irreversibly damages and reorganises underwater sites, often resulting in the loss of archaeological material and its contexts (e.g. Brennan et al. 2016). Additionally, fishing nearby wrecks frequently results in equipment entanglement, snagging of nets and their abandonment, leaving behind so-called 'ghost nets', posing threats to marine fauna and recreational divers, and acting as a source of microplastics (Andrady 2011). ...
... In parallel, sediment samples can be collected with grabs or cores to obtain physical samples of substrates. Surveys can be repeated at various time intervals, using a timelapse approach (Quinn and Boland 2010;Bates et al. 2011;Stieglitz and Waterson 2013;Astley 2016;Brennan et al. 2016;Fernández-Montblanc et al. 2016). In archaeology and heritage science, the time-lapse strategy has been employed predominantly for wooden wrecks (Manders 2009;Quinn and Boland 2010;Astley 2016;Brennan et al. 2016). ...
... Surveys can be repeated at various time intervals, using a timelapse approach (Quinn and Boland 2010;Bates et al. 2011;Stieglitz and Waterson 2013;Astley 2016;Brennan et al. 2016;Fernández-Montblanc et al. 2016). In archaeology and heritage science, the time-lapse strategy has been employed predominantly for wooden wrecks (Manders 2009;Quinn and Boland 2010;Astley 2016;Brennan et al. 2016). As noted by Astley (2016), who researched stability of three upstanding metal-hulled wrecks, there is a need to expand the number of case studies in order to have better understanding of wreck site formation pathways. ...
Shipwrecks not only provide unique opportunities to investigate relatively unaltered archaeological deposits, but they are also linked to environmental, heritage management and marine spatial planning issues. Physical processes, comprising linked hydro- and sediment-dynamics, can determine the pathways of evolution of shipwreck sites. For example, water flowing around a submerged wreck may cause scour, and together with changes in local geomorphology, can greatly influence the preservation state of the wreck. This geomorphic change can be exacerbated further by anthropogenic activities. This complex interplay between hydro-dynamics, geomorphic change, anthropopressure and structural deterioration remains poorly understood. Consequently, monitoring and management strategies capable of conserving this vast and finite submerged resource remain inefficient.
This thesis aims to extend our knowledge of the influence of combined sediment- and hydro-dynamic processes on the in-situ preservation of fully submerged, historic wreck sites. This study uses multibeam echosounder (MBES) data of exceptional, centimetric resolution collected over ten metal-hulled shipwrecks standing proud on the seabed in the Irish Sea between water depths of 26 and 84 m. Additional seabed and sub-seabed geological and hydrodynamic data are derived from sediment grabs, shallow-seismics and an oceanographic model. This unique combination of datasets is used in three complementary studies corresponding to the research objectives set out in the thesis.
Residual relief modelling (RRM) is tested for the objective mapping and delineation of wreck-related scour features, enabling their quantitative description. RRM relies on high-pass filtering of digital elevation model (DEM) data and is enhanced with breakpoint classification, with final separation of the features of interest supported by DEM visualisation enhancement techniques. The results indicate that the semi-automated workflow is time-efficient and quantifies the products of scour with improved objectivity when compared to manual digitisation. Development of the method has important implications for site formation studies and decision-making in in-situ preservation planning.
The temporal and spatial scales at which sediment erosion and deposition occur around wrecks remain largely unknown. Analysis of timelapse MBES survey data successfully captures true site extents and allows for the investigation of weekly, annual, multi-annual and decadal seabed changes, significantly expanding the number of case-studies reported for shipwreck site scour. Results of difference modelling show major changes at all time intervals for sites located in sand‐dominated environments, whereas the seabed around wrecks settled in multimodal sediments shows virtually no geomorphic change outside of vertical measurement uncertainty (±30 cm). Quantification of local environmental processes and factors, including bed shear stress, sediment supply, and spatial barriers to scour explains variability in geomorphic change and aids predictions of future site dynamics. The study demonstrates that individual wrecks in similar shelf sea regions can be in very different equilibrium states with their environment, which has critical implications for their in-situ management.
Computational fluid dynamics (CFD) is used in conjunction with high-resolution MBES data-derived 3D wreck models to simulate tidal flows at two contrasting sites. Intricate patterns of wake and horseshoe vortices are observed, and modelled wall shear stresses successfully explain geomorphic change recorded in 4-year and one-week interval difference models. Moreover, substantial damage is detected on the wreck structures, correlated with areas of elevated wall shear stress and pressure in CFD simulations. The combined approach aids site management and provides analogies for offshore engineering.
It is anticipated that new knowledge realised in this study on the multi-method characterization of physical site formation processes at shipwreck sites will aid decision making in underwater heritage management and marine spatial planning.
... Present-day seabed mapping technology and techniques allow for precise, nonintrusive mapping of underwater archaeological sites with centimetric precision Ødegård et al., 2018;Plets et al., 2011;Westley et al., 2011Westley et al., , 2019. It is now possible not only to detect and identify shipwrecks remotely, but also to analyze and quantify geomorphic change at underwater sites through repeat high-resolution multibeam echosounder (MBES) bathymetric surveys (Astley, 2016;Bates et al., 2011;Brennan et al., 2016;Quinn & Boland, 2010;Stieglitz & Waterson, 2013). Moreover, buried parts of shipwrecks and subseabed records of site formation processes can be imaged using shallow seismic techniques (Cvikel et al., 2017;Geraga et al., 2020;Grøn et al., 2015;Plets et al., 2009;Quinn et al., 1997). ...
... To fully understand the dynamics of scour development, however, high-resolution bathymetric surveys should be conducted at least two times. This approach, referred to as "time-lapse" or "repeat surveying," has not been used very often to date (e.g., Astley, 2016;Bates et al., 2011;Brennan et al., 2016;Quinn & Boland, 2010;Stieglitz & Waterson, 2013), considering that 3 million shipwrecks are estimated worldwide (Croome, 1999;UNESCO, 2017). ...
... Nevertheless, it is important to understand that the stability of underwater sites is not solely controlled by their geomorphological and hydrodynamic settings. A disruption of any equilibrium state can be triggered by external anthropologic influences like digging (Manders, 2009), trawling (Brennan et al., 2016), or dredging operations (Quinn & Boland, 2010). In this study, a direct indication that anthropogenic activity impacts the sites is evidenced by the trawl marks at FV St. Michan. ...
Shipwrecks are an integral part of our maritime archaeological landscape and are associated with diverse societal and cultural interests, yielding significant management challenges. Coupled hydrodynamic and geomorphological processes significantly impact the effective in-situ preservation of these fragile sites. Here we assess sediment budget change and hydrodynamic triggers at metal-hulled shipwrecks lost between 1875 and 1918, all located in the tidally dominated Irish Sea at depths between 26 and 84 m. This is conducted using time-lapse, multibeam echosounder surveys at multiannual, annual and weekly time-steps, supported by sediment grain-size analysis, modelled ocean currents and shallow-seismic data. Results indicate significant changes at all time-steps for sites located in sand dominated environments, while the seabed around shipwrecks settled in multimodal sediments shows virtually no change outside of measurement errors (±30 cm). Variability in geomorphic change is attributed to local environmental factors, including bed shear stress, sediment supply and spatial barriers to scour. We demonstrate that individual wrecks in similar shelf sea regions can be in very different equilibrium states, which has critical implications for the in-situ management of underwater cultural heritage.
... La pesca conlleva potenciales impactos negativos al PA, principalmente en el uso de redes y rastras de fondo (Guijarro, 2007;Evans et al., 2009;Brennan et al., 2016), y sistemas de fondeo (Maarleveld et al., 2013). Estos incluyen la afectación de embarcaciones hundidas, alteración de superficies naturales del fondo y remoción de sedimentos (Brennanet al., 2016). ...
... Los impactos directos refieren a consecuencias con implicancias físicas directas sobre los restos culturales, que van desde una alteración de superficie, hasta la modificación de su estructura o configuración espacial. Baker, 2016;Brennan et al., 2016;Claesson, 2009;Cohn, 2003;Devis et al., 2016;Erandson y Fitzpatrick, 2006;Evans et al., 2009;Guijarro, 2007;Harris et al., 2016;Maarleveld et al., 2013;Manzi y Borrella, 2014;Pérez Alonso, 2013;Simcock, 2016;Smith y Couper, 2003;Terrel, 2003. Los paisajes prehistóricos sumergidos y el registro arqueológico prehistórico en la PC vienen siendo estudiados en otras regiones (Faught, 2004;Bailey y Flemming, 2008;Gusick y Faught, 2011;Flatman y Evans, 2014). ...
... Entre los principales impactos de esta zona están los fondeos, según el tipo de embarcación y propósito, con efectos como abrasión y daño en los ecosistemas bentónicos (Collins et al., 2010;Brennan et al., 2016;Davis et al., 2016), destrucción de sitios arqueológicos, erosión de superficies, rotura y remoción de partes . Grandes cruceros reportan impactos negativos en ecosistemas bentónicos por sus sistemas de propulsión, resuspendiendo sedimento en grandes cantidades durante maniobras de fondeo (Jones, 2011). ...
Uruguay faces a new challenge in managing the country's coastal and maritime archaeological heritage. Diversification and intensification of activities on the coast and in the marine environment put at risk a cultural heritage that has very weak legal protection and lacks strong public management policies. This work collects information on the current situation of the country's coastal and maritime archaeological heritage, its legal-administrative status and the new scenarios of economic development in the coastal area, continental shelf and Offshore. It reviews the main impacts and threats that these socioeconomic activities cover for this heritage. Concludes by emphasizing the necessary articulation of cultural heritage resource management within the framework of Integrated Coastal Management and Marine Spatial Planning, which enable Brum Bulanti, L., de Álava, D., Chocca, Y., Marín, Y., 2020. With the backs to the Sea. Challenges for an Integrated Management of the Coastal and Maritime Archaeological Heritage of Uruguay. Revista Costas, 2(1): 81-104.
... La pesca conlleva potenciales impactos negativos al PA, principalmente en el uso de redes y rastras de fondo (Guijarro, 2007;Evans et al., 2009;Brennan et al., 2016), y sistemas de fondeo (Maarleveld et al., 2013). Estos incluyen la afectación de embarcaciones hundidas, alteración de superficies naturales del fondo y remoción de sedimentos (Brennanet al., 2016). ...
... Los impactos directos refieren a consecuencias con implicancias físicas directas sobre los restos culturales, que van desde una alteración de superficie, hasta la modificación de su estructura o configuración espacial. Baker, 2016;Brennan et al., 2016;Claesson, 2009;Cohn, 2003;Devis et al., 2016;Erandson y Fitzpatrick, 2006;Evans et al., 2009;Guijarro, 2007;Harris et al., 2016;Maarleveld et al., 2013;Manzi y Borrella, 2014;Pérez Alonso, 2013;Simcock, 2016;Smith y Couper, 2003;Terrel, 2003. Los paisajes prehistóricos sumergidos y el registro arqueológico prehistórico en la PC vienen siendo estudiados en otras regiones (Faught, 2004;Bailey y Flemming, 2008;Gusick y Faught, 2011;Flatman y Evans, 2014). ...
... Entre los principales impactos de esta zona están los fondeos, según el tipo de embarcación y propósito, con efectos como abrasión y daño en los ecosistemas bentónicos (Collins et al., 2010;Brennan et al., 2016;Davis et al., 2016), destrucción de sitios arqueológicos, erosión de superficies, rotura y remoción de partes . Grandes cruceros reportan impactos negativos en ecosistemas bentónicos por sus sistemas de propulsión, resuspendiendo sedimento en grandes cantidades durante maniobras de fondeo (Jones, 2011). ...
The Mirim Lagoon, a cross-border lagoon system between Brazil and Uruguay, poses a challenge for environmental management and planning. With the imminent implementation of the Brazil-Uruguay Waterway, freight transportation would increase significantly along the lagoon and, consequently, the pressures on other water users and the environment. In the face of this scenario, the Rio Grande do Sul ecological-economic zoning terms of reference recognize the lagoon as a strategic area. However, there is a lack of methodologies that address overlapping use and are applicable to aquatic systems, and at the same time have a good potential of acceptance by the actors
involved in the process. Thus, the goal of this work is to propose an index based on the relationships between the different beneficiaries of the environmental services provided by Mirim Lagoon, as an alternative approach to the traditional conflict analysis. To build and spatialize the Compatibilization Demand Index (CDI), the environmental systems of Lagoa Mirim and adjacent municipalities were initially identified and characterized. Although CDI was applied only to environmental systems inside the lagoon and its margins, it was necessary to detect their indirect beneficiaries (those who use services provided by the lagoon and margins but are physically located in other areas of the municipalities part of the drainage basin). The final result is a map on a Likert scale (1-5) portraying which systems have a greater overlapping uses and environmental services competition. The environmental systems in the protected inlets and waterway channel are, according to the results, the ones that demand a greater intensity of management. Although simple, the result is based on a relatively complex logic but easily understandable and accepted by the actors involved in comparison to the approaches traditionally adopted for conflict analysis. The results presented here served as subsidies, along with other analyzes, in the zoning of the Lagoon Mirim within the scope of the ZEE-RS, whose classification is based on the intensity of management demanded by each environmental system.
... Shipwrecks are subject to stressors from climate change, including acidification, sea level rise, and more frequent and intense storms (Wright, 2016). Fishing, especially bottom trawling and dredging, poses a risk to shipwrecks through direct contact and entanglement of ghost gear (Brennan et al., 2016). ...
... The impact of entangled fishing gear on shipwreck communities is not uniform, and more research is required to understand the mechanisms and long-term ecological impacts. Fishing gear damages and accelerates the degradation of historical shipwrecks (Brennan et al., 2016). Therefore, we expect that ghost gear will have a net negative impact on the invertebrate communities on SBNMS shipwrecks over time. ...
Shipwrecks are irreplaceable historical resources and valuable biological habitats. Understanding the environmental and anthropogenic factors affecting shipwrecks is critical for preservation in situ. We used remotely operated vehicles to study the benthic invertebrate communities on four shipwrecks in Stellwagen Bank National Marine Sanctuary (SBNMS, North Atlantic, USA). Shipwrecks included coal schooners and a passenger steamer, all >100 years old. These large, complex structures hosted dense populations of invertebrates (34 species), especially on high-relief and overhanging substrata. Some species that are otherwise rare in the community may proliferate through asexual reproduction and form dense populations on shipwrecks. We also investigated impacts of entangled fishing gear on the invertebrate communities on each shipwreck and found that areas with the most ghost gear have lower species richness and different community structure. Fishing, particularly bottom trawling, damages shipwrecks and poses a threat to these valuable cultural resources and biological habitats in SBNMS.
... Since its first mention in an English 1376 parliamentary petition, trawling has been regarded as a catastrophically damaging practice with long-lasting negative consequences for seabed ecology and marine life (Roberts 2007). Although legislation that limits trawling can help biological communities rebound, the archaeological material lost can never be recovered (Brennan et al. 2015). Maritime archaeologists and marine ecologists need to communicate and work together with fishers and policy makers to find ways to limit harm. ...
Our ocean heritage (natural and cultural) is at risk from destructive human activities, including bottom trawling, deep seabed mining (DSM), and potentially polluting wrecks (PPWs). The stories of our societies and our ancestors are often connected with the ocean and captured on the seafloor as artifacts, shipwrecks and the remains of those lost or buried at sea. Previously, marine global heritage protection efforts have been largely focused on natural heritage. However, Underwater Cultural Heritage (UCH) is also ocean heritage and must be considered the same way. We must shine a light on UCH as heritage and insist that it be part of Marine Spatial Planning with integrated ocean and coastal management. Approaches include, but are not limited to, (1) Conducting baseline surveys to identify heritage that should be conserved and preserved for present and future generations; (2) Environmental assessments taking into account the impact of human activities on both natural and cultural heritage; (3) Measures to identify, avoid or minimize the adverse impacts; and (4) The application of a precautionary approach to trawling, DSM and salvage of PPWs, calling for a moratorium on these activities unless and until steps 1 – 3 have been accomplished, permits/other management controls are in place and significant natural and cultural sites have been designated as protected areas.
... This methodology can be adjusted and expanded to include other natural or anthropogenic-induced hazards. There are some studies that focus on other specific hazards such us ship anchoring damage (Aps et al., 2020) or damage caused by bottom trawling to ancient shipwreck sites (Brennan et al., 2016). To the best of our knowledge, no similar methodological developments have been applied to UCH risk assessment to evaluate wave impact. ...
Memoria anual del Laboratorio de Estudios y Conservación del Patrimonio Histórico de la Universidad de Cádiz, año 2022
... This methodology can be adjusted and expanded to include other natural or anthropogenic-induced hazards. There are some studies that focus on other specific hazards such us ship anchoring damage (Aps et al., 2020) or damage caused by bottom trawling to ancient shipwreck sites (Brennan et al., 2016). To the best of our knowledge, no similar methodological developments have been applied to UCH risk assessment to evaluate wave impact. ...
Coastal areas are characterized by high energetic conditions associated to the wave transformation process and by numerous underwater cultural heritage (UCH) sites whose preservation is crucial given their cultural and economic value. UCH management requires a decision support system to prioritize UCH interventions and actions for long-term preservation. This paper presents a novel UCH risk assessment methodology to quantitatively assess the impact of wave-induced hazards on UCH in coastal environments at a local level and the screening of UCH sites at risk. The UCH risk is calculated as a function of vulnerability (depending on archaeological materials, slope, and seabed type), hazard (decontextualization, scouring, and erosive wear), and exposure computed for the UCH sites registered in an archaeological database. The procedure was validated at two shipwreck sites, Bucentaure and Fougueux , in the Bay of Cadiz. An agreement between the risk index value and the in situ measurements of the rates of scouring and corrosion (used as a proxy of erosive wear) was observed. The methodology was tested in the Bay of Cadiz using an archaeological database containing 56 UCH sites. It allowed identifying the UCH sites at high risk: six are at risk of decontextualization, four are in peril of scouring erosion, and two are at risk of erosive wear. Two UCH sites at high risk of at least two hazards were also identified. This UCH risk assessment methodology is a stepping stone towards a decision support system that will give priority to research, prospection, management, and protection measures in the UCH sites analyzed to ensure their preservation in a context of climate change in the era of a sustainable blue economy.
... Development is one of the most potent threats to underwater cultural heritage near shore but trawling has potentially disastrous impacts on historic wrecks in offshore fishing grounds. The impacts of trawling on both submerged heritage and on benthic communities has been a source of concern at least since the 1980s (Betts, 2000), and more recently (Brennan et al., 2016). ...
Between 2015 and 2017 the Black Sea Maritime Archaeology Project (Black Sea MAP) discovered and recorded 65 shipwreck sites dating from the 4th Century BC to the 19th Century AD in the Bulgarian Exclusive Economical Zone (EEZ). Using state-of-the-art remotely operated vehicles to survey the seabed, the team captured more than 250,000 high-definition (HD) photographs; hundreds of hours of ultra high-definition (UHD) video together with acoustic bathymetric, laser, side-scan sonar and seismic data. The wrecks were located in depths from 40 to 2200 m – those shipwrecks in the deeper range presented extraordinary archaeological preservation due to the Black Sea's anoxic conditions. This paper will introduce the range of deep-sea optic and acoustic survey techniques to accurately record and create 3D and pseudo 4D models of the shipwrecks. It will focus on a Early 4th Century BC shipwreck demonstrating the project's survey strategy as well as adaptations developed in response to operational conditions; the implementation of deep sea robotics to generate georeferenced high-resolution photogrammetric models and the benefits this has as an on-site, as well as a post-cruise, interpretative tool. It demonstrates that in-theatre acquisition and processing of high-quality datasets is a working reality and has fundamental implications for management as well as the advantages that this brings to the archaeological research process: Firstly, in the creation of spatio-temporal models, i.e., 4D representations of a site pre and post archaeological excavation and secondly, in monitoring such wreck sites, and provides a viable non-intervention tool for the assessment of sites as part of a long-term management strategy. It also shows the value of well-funded collaboration between academia and industry and that deep water archaeology can and must be totally in accordance to the 2011 United Nations Educational, Scientific and Cultural Organization (UNESCO) convention.
... Climate-related acidification, erosion, and intense storms accelerate the degradation of UCH. Fishing, especially bottom trawling, damages UCH and leads to the entanglement of ghost gear [11]. Eutrophication alters the community structure on otherwise similar shipwrecks [12]. ...
Underwater cultural heritage (UCH) supports marine biodiversity and influences connectivity. UCH structure, colonizing organisms, and anthropogenic stressors interact to shape sites over time, but these interactions are poorly understood. Here, we express the urgent need for biology–archeology collaborations to address interdisciplinary questions. We also codify the emerging field of Maritime Heritage Ecology.
... This is supported by the doubling of sedimentation rates from 0.11 to 0.21 cm⋅yr -1 at ~800 m within the canyon (OC-800), which is located beyond the trawled canyon axis (Fig. 5). In fact, the tectonic high located at 750 m in the axis limits trawling grounds, because these geomorphological obstructions promote gear loss (Brennan et al., 2016;Eigaard et al., 2017;Richardson et al., 2018). Hence, the downcanyon transferal of suspended sediment by bottom trawling along the canyon axis increased sedimentation rates in even deeper areas located farther offshore. ...
Bottom trawling in submarine canyons can affect their natural sedimentation rates, but studies addressing this issue are still scarce. In the Gulf of Palermo (SW Mediterranean), bottom trawling occurs on the slope around Oreto, Arenella and Eleuterio canyons. Analyses of excess ²¹⁰Pb concentrations and grain size fractions in sediment cores from their canyon axes revealed that sedimentation rates and silt contents increased in all canyons in the 1980s, due to the expansion of more powerful trawlers (>500 HP) to deeper fishing grounds. In Eleuterio and Arenella canyons, sedimentation rates increased by an order of magnitude (0.1-1.4 cm·yr⁻¹), whereas they increased less (0.1-0.7 cm·yr⁻¹) in Oreto Canyon, since the enhanced trawling-derived sediment fluxes into this canyon are affected by sediment resuspension from trawling along its axis. Considering the global expansion of bottom trawling, we anticipate similar alterations in other trawled canyons, with ecological consequences that should be addressed by management strategies.
... For example, the early Hellenistic Ereğli E shipwreck in the southern Black Sea suffered repeated trawling over the course of 11 months, during which time much of what had been documented upon its discovery had been displaced or removed. 111 The VMS study by R. O. Amoroso and colleagues shows the heaviest levels of trawl activity in parts of the Mediterranean and Baltic seas 112 coniciding with where ancient shipwrecks are located. As exploration of Turkish waters expanded, further evidence of the impact of trawling has been obtained. ...
Deep-water shipwrecks provide an opportunity to investigate ships away from the destructive dynamics of coastlines and approaches to harbors where most ancient wrecks to date have been found. Such exploration expands the potential for finding wrecks of periods for which relatively few are known. One such period is the 6th and 7th c. in the E Mediterranean. Studies of cargo assemblages from the few known wrecks of the later Roman period reveal a partial picture of interlinked and overlapping trade networks that incorporated major and minor ports in the adjacent provinces. ¹ Various trading modes may be discerned, including cabotage, short-haul trade, inter-regional commerce, and private long-haul trade. Largely missing thus far are the wrecks of ships that participated in the annona transport, the “backbone of Late Roman shipping”. ² Each year, an enormous fleet of private ships under state contract hauled thousands of shiploads of Egyptian grain from Alexandria to Constantinople for public distribution,3 but no shipwrecks explicitly associated with these fleets have been found. Also largely invisible are the non-commercial transports associated with the annona militaris , the fiscal supply of foodstuffs destined for armies stationed on the empire‘s borders. The state supply-system became more formalized in 536 when Justinian created the quaestura exercitus , a prefecture that was granted administrative control and jurisdiction of Moesia Secunda, Scythia , Caria, the Aegean islands, and Cyprus. ⁴ Evidence suggests that the quaestor‘s main task was to ensure the supply, by sea, of agricultural products from the Aegean and NE Mediterranean to troops on the Danube frontier. ⁵ While no definitive grain ships have been found in the E Mediterranean — what M. McCormick has called the “annona paradox” ⁶ —, shipwrecks with the larger cargoes expected of state supply have remained rather elusive.
... Development is one of the most potent threats to underwater cultural heritage near shore but trawling has potentially disastrous impacts on historic wrecks in offshore fishing grounds. The impacts of trawling on both submerged heritage and on benthic communities has been a source of concern at least since the 1980s (Betts, 2000), and more recently (Brennan et al., 2016). ...
Between 2015 and 2017 the Black Sea Maritime Archaeology Project (Black Sea MAP) discovered and recorded 65 shipwreck sites dating from the 4th Century BC to the 19th Century AD in the Bulgarian Exclusive Economical Zone (EEZ). Using state-of-the-art remotely operated vehicles to survey the seabed, the team captured more than 250,000 high-definition (HD) photographs; hundreds of hours of ultra high-definition (UHD) video together with acoustic bathymetric, laser, side-scan sonar and seismic data. The wrecks were located in depths from 40 to 2,200 metres – those shipwrecks in the deeper range presented extraordinary archaeological preservation due to the Black Sea’s anoxic conditions. This paper will introduce the range of deep-sea optic and acoustic survey techniques to accurately record and create 3D and pseudo 4D models of the shipwrecks. It will focus on a Early 4th Century BC shipwreck demonstrating the project’s survey strategy as well as adaptations developed in response to operational conditions; the implementation of deep sea robotics to generate georeferenced high-resolution photogrammetric models and the benefits this has as an on-site, as well as a post-cruise, interpretative tool. It demonstrates that in-theatre acquisition and processing of high-quality datasets is a working reality and has fundamental implications for management as well as the advantages that this brings to the archaeological research process: Firstly, in the creation of spatio-temporal models, i.e., 4D representations of a site pre and post
archaeological excavation and secondly, in monitoring such wreck sites, and provides a viable non-intervention tool for the assessment of sites as part of a long-term management strategy. It also shows the value of well-funded collaboration between academia and industry and that deep water archaeology can and must be totally in accordance to the 2011 United Nations Educational, Scientific and Cultural Organization (UNESCO) convention.
... Development is one of the most potent threats to underwater cultural heritage near shore but trawling has potentially disastrous impacts on historic wrecks in offshore fishing grounds. The impacts of trawling on both submerged heritage and on benthic communities has been a source of concern at least since the 1980s (Betts, 2000), and more recently (Brennan et al., 2016). ...
Between 2015 and 2017 the Black Sea Maritime Archaeology Project (Black Sea MAP) discovered and recorded 65 shipwreck sites dating from the 5th/4th Century BC to the 19th Century AD in the Bulgarian EEZ. Using state-of-the-art remotely operated vehicles to survey the seabed, the team captured more than 250,000 high-definition (HD) photographs; hundreds of hours of ultra-high (UHD) video together with acoustic bathymetric, laser bathymetric, side-scan sonar and seismic data. The wrecks were located in depths from 40 to 2,200 metres – those shipwrecks in the deeper range presented extraordinary archaeological preservation due to the Black Sea’s anoxic conditions. This paper will introduce the methods used based on a wide range of deep-sea optic and acoustic survey techniques to create 3D and pseudo 4D models of the shipwrecks.
... Bottom trawling has destructive effects on priority habitats (e.g., coral community, coralligenous formations, seagrass beds) which are targets for conservation actions [12][13][14]. In addition, marine geoarchaeological sites have also been heavily impacted by trawl-fishing [15,16]. The amount of the damage done depends on the spatial extent and the frequency of trawling [17]. ...
Bottom trawl footprints are a prominent environmental impact of deep-sea fishery that was revealed through the evolution of underwater remote sensing technologies. Image processing techniques have been widely applied in acoustic remote sensing, but accurate trawl-mark (TM) detection is underdeveloped. The paper presents a new algorithm for the automatic detection and spatial quantification of TMs that is implemented on sidescan sonar (SSS) images of a fishing ground from the Gulf of Patras in the Eastern Mediterranean Sea. This method inspects any structure of the local seafloor in an environmentally adaptive procedure, in order to overcome the predicament of analyzing noisy and complex SSS images of the seafloor. The initial preprocessing stage deals with radiometric inconsistencies. Then, multiplex filters in the spatial domain are performed with multiscale rotated Haar-like features through integral images that locate the TM-like forms and additionally discriminate the textural characteristics of the seafloor. The final TMs are selected according to their geometric and background environment features, and the algorithm successfully produces a set of trawling-ground quantification values that could be established as a baseline measure for the status assessment of a fishing ground.
... In partnership with Turkish colleagues, the expedition adopted the principle of in situ preservation as a first option in accord with the UNESCO Convention for the Protection of the Underwater Cultural Heritage (UNESCO, 2001) and implemented a non-intrusive, non-sampling mode of survey and mapping. Eregli E, the oldest of the 12 wrecks, was mapped after its initial discovery in 2011, then remapped the following year (Davis et al., 2014;Brennan et al., 2016) (Fig. 2). This early Hellenistic merchant ship rests on a flat seabed at 101m depth, approximately 11nm north of Kefken Adası and 52nm west of Eregli. ...
... It should be noted that beyond the natural processes, the anthropogenic influence on the scattering of underwater archaeological remains, e.g. the bottom trawl fishing described by Brennan et al. (2016), should be considered as a limitation in the use of scattered remains as palaeocoastline indicator. ...
Shoreline evolution studies are mostly performed by comparison of vertical images (e.g. aerial photographs and satellite imagery), being limited to the last decades. However, phenomena such as longer term climatic fluctuations may cause important secular coastal changes which are mostly unknown. The use of archaeological remains as shoreline proxies could overcome this limitation by allowing to expand back in time the historical shoreline record. The present study endorses the effectiveness of the use of shipwrecks and man-made structures as proxy data for analyzing historical shoreline evolution. This was confirmed by the evaluation of nearshore evolution (historical shorelines from 1787 to 1823 and recent changes from 1956 to 2013) and the reconstruction of the palaeobathymetry along Sancti Petri sand spit (SW Spain) by means of the analysis of historical documents, historical maps, modern aerial photographs and a recent bathymetry (2011), along with the archaeological prospection supported by the numerical modelling of the dispersion of archaeological remains. The analysis of historical maps has revealed a significant shoreline retreat over the medium term scale in Sancti Petri sand spit, averaging − 1.2 m·year− 1. Results from historical maps and archaeological remains show slight differences with respect to the most recent retreat rates (− 0.9 m·year− 1) obtained from aerial photographs for the period 1956–2013. Spatial variations in coastal retreat along the sandspit are closely linked to local patterns of wave height and wave-induced currents. Significant temporal variation in rates of shoreline change was observed, probably related to storminess variability in the study area, as indicated by the relation between the rates of coastal change for each analyzed period and the corresponding rate of change of winter NAO index.
... Increasingly, baseline morphological surveys of submerged shipwreck sites employ multibeam echosounders (Plets et al. 2011), with further inspections at (ir)regular intervals to assess change in site integrity (Manders 2009; Quinn and Boland 2010; Bates et al. 2011; Astley et al. 2014). Over time, this can lead to sophisticated models of erosion and deposition (Manders 2009; Astley et al. 2014; Brennan et al. 2016), albeit at a very high financial cost. Another drawback is that these approaches only allow the patterns of erosion and deposition to be investigated, with causative processes only inferred from the results. ...
Shipwreck sites are open systems, allowing the exchange of material and energy across system boundaries. Physical processes dominate site formation at fully submerged wreck sites, and in turn influence chemical and biological processes at many stages of site formation. Scouring presents a fundamental yet poorly understood threat to wreck sites, and the processes and patterns of erosion and deposition of sediments and artefacts at wreck sites are poorly understood. Laboratory and field-based experiments to study these phenomena are time-consuming and expensive. In this study, open-source computational fluid dynamic (CFD) simulations are used to model the processes and patterns of flow, erosion, and deposition at fully submerged wreck sites. Simulations successfully capture changes in the flow regime in the environment of the wreck as a function of incidence angle, including flow contraction, the generation of horseshoe vortices in front of the wreck, the formation of lee-wake vortices behind the structure, and increased turbulence and shear stress in the lee of the wreck site. CFD simulations demonstrate that horseshoe vortices control scour on the upstream face of structure but play a minimal role in scouring on the lee side. Lee-wake vortices dominate behind the structure, with low-pressure zones in the lee of the wreck capturing flow. The amplification and reduction of wall shear stress and turbulent kinetic energy in the lee of the vessel form distinctive patterns in relation to flow direction, with areas of amplified and reduced wall shear stress and turbulent kinetic energy demonstrating excellent spatial correlation with erosional and depositional patterns developed at real-world wreck sites.
... Bottom trawl fishing is among the most destructive anthropogenic pressures acting on benthic ecosystems, but the full extent of the damage is undocumented because of the limited number of deep-sea observations of impacted regions (e.g., Brennan et al., 2012Brennan et al., , 2016. As part of its continuing ocean exploration mission, in 2011, E/V Nautilus conducted a remotely operated vehicle (ROV) survey along a transect in a submarine canyon in the Mediterranean's Alboran Sea off southern Spain at depths ranging from 1,200 m to <300 m . ...
Trawling has long been regarded as a damaging practice and marine ecologists have lobbied for restrictions. The damage to Underwater Cultural Heritage (UCH), however, has received less attention, though it is just as consequential. This paper looks at UCH damage case studies and the impacts of heritage loss and then suggests steps forward. The case studies in the paper will include the damage to UCH across the ocean and in the Mediterranean and Black seas. Shipwrecks are as much part of the marine landscape, and thus of importance to ecologists, as they are to the cultural, historical landscape. Yet nothing has been done to seriously limit trawling and protect the underwater cultural landscape and archaeological impacts and data are missing from biological reports on the process. No underwater policies based on cultural preservation have been formulated to manage offshore fishing. There is a preferred policy for in situ preservation in the 2001 UNESCO Convention on the Protection of Underwater Cultural Heritage and some practical measures for site managers to address the threats from bottom trawling but if in situ preservation is to be supported, more needs to be done. Moorings can be added and shipwrecks, if left in place, can become artificial reefs and places for more artisanal, sustainable hook-and-line fishing. However, what is needed most is for states and international fishing organisations to ban bottom trawling at and around identified UCH sites, as has been done for some seamounts. This work is part of the Threats to Our Ocean Heritage project, a UN Decade for Ocean Science approved Action discussing this issue of Trawling, Deep Seabed Mining, and Potentially Polluting Wrecks. The expected results include ocean literacy that increases awareness of the issue to a wider range of stakeholders including international organisations, states, and institutions with the authority to effectuate change.
Shipwrecks are irreplaceable cultural and historical resources, and they also serve as biological habitats. The physical structure of a shipwreck provides habitat for hard-bottom organisms, including sessile invertebrates (anemones, sponges) and protected areas for fish. The structure of a shipwreck is influenced by cultural and natural site formation processes over time. A key unanswered question is: How do site formation processes and changes in biological communities (ecological succession) influence one another? We studied the shipwreck Portland in Stellwagen Bank National Marine Sanctuary to answer this question, working within the interdisciplinary framework of Maritime Heritage Ecology. Analysis of sonar and video data from 2002 to 2010 and 2019–2021 revealed substantial structural changes to the bow, freight deck, and stern. Site formation on the bow and stern was clearly anthropogenic, as shown by entangled fishing ghost gear. The assemblage of sessile invertebrates in each of the three shipwreck areas also saw changes in community structure, including changes in the relative abundance of species. We also observed changes in the fish community, but these are more likely the result of regional climatic change. Overall, our study showed that ghost gear is a significant threat to Portland and other shipwrecks in Stellwagen, and that site formation drives changes in the biological community over time.
Shipwrecks are irreplaceable cultural and historical resources, and they also serve as biological habitats. The physical structure of a shipwreck provides habitat for hard-bottom organisms, including sessile invertebrates (anemones, sponges) and protected areas for fish. The structure of a shipwreck is influenced by cultural and natural site formation processes over time. A key unanswered question is: how do site formation processes and changes in biological communities (ecological succession) influence one another? We studied the shipwreck Portland in Stellwagen Bank National Marine Sanctuary to answer this question, working within the interdisciplinary framework of Maritime Heritage Ecology. Analysis of sonar and video data from 2002–2010 and 2019–2021 revealed substantial structural changes to the bow, freight deck, and stern. Site formation on the bow and stern was clearly anthropogenic, as shown by entangled fishing ghost gear. The assemblage of sessile invertebrates in each of the three shipwreck areas also saw changes in community structure, including changes in the relative abundance of species. We also observed changes in the fish community, but these are more likely the result of regional climatic change. Overall, our study showed that ghost gear is a significant threat to Portland and other shipwrecks in Stellwagen, and that site formation drives changes in the biological community over time.
Since its first mention in a fourteenth-century parliamentary petition, trawling has been regarded as a catastrophically damaging practice with lasting negative consequences on seabed ecology and marine life. Trawling has also had dramatic impacts on maritime archaeology sites, though that side of trawling does not get enough coverage. All three trawling revolutions—invention, mechanization, and later deep-water expansion—have been met with controversy and pushback by the public and environmentalists alike. The practice has enabled humans to exploit the sea and destroy their own history at the same time. Maritime archaeologists and marine ecologists need to communicate and work together to lobby for trawl bans. Shipwrecks are as much part of the marine landscape, and thus of importance to ecologists, as they are to the cultural, historical landscape.
Yet nothing has been done to seriously limit the practice and protect the underwater cultural landscape and archaeological impacts and data are missing from biological reports on the process. No underwater policies have been formulated to manage offshore fishing based on cultural preservation. Some trawling restrictions have been placed after backlash in the 1990s and ecologists, well aware of the dangers of trawling, have lobbied for more restrictions. This research and advocacy for regulation are a good start, but none of this stems from concern or activism by archaeologists. UNESCO has only recently raised concerns, and, will hopefully lead efforts to address this threat. There is a preferred policy for in situ preservation in the 2001 Convention and some practical measures for site managers to address the threats from bottom trawling. If in situ preservation is to be supported, moorings can be added and shipwrecks, if left in place, can become artificial reefs and places for more artisanal, sustainable hook-and-line fishing. However, what is most needed is for states and international fishing organizations to ban bottom trawling at and around identified UCH sites as has been done for some seamounts.
This study offers a methodology for field survey and analysis of artifact-rich contexts in near-shore waters. Faced with mixed deposition of fragmentary ceramics and other materials along the tectonically active southern Turkish coast at Kekova Adası, we combined rapid artifact counts, in situ object documentation, large-area photogrammetry, and selective artifact sampling. Quantitative and qualitative analyses of published shipwrecks and anchorages, as well as onshore port assemblages throughout the area, facilitate comparison with these mixed maritime remains at Kekova Adası, allowing signatures to be distinguished among different depositional contexts, from transshipment and anchoring to harbor tasks and local consumption. The approach provides a framework to evaluate more systematically the underwater survey finds from complex and disturbed contexts and to analyze a broader range of often-overlooked archaeological data in the study of the many maritime activities and interactions that marked the coastal waters of the ancient Mediterranean.
During the campaign of 2018 the international underwater archaeological expedition has explored the waters of Tendra Spit and Kinburn Spit on the shelf of the Black Sea, in Mykolaiv and Kherson regions of Ukraine. Underwater archaeological exploration focused on the waters near the northern tip of Tendra Spit, from both the Gulf of Tendra and the sea, and north-western tip of Kinburn Spit. In addition to the visual reconnaissance, divers were using sonar, profiler and side-scan sonar. As a result, the bathymetric map has been compiled. In the initial part of research the work was limited to mapping and taking photographs of the discoveries. During these works was discovered and cleansed the ancient Shipwreck of the late 4th — early 3rd century BC. It was possible to identify the well-preserved fragment of the hull of ancient Wreck of a length of 9.45 m in situ with ballast stones, ceramic material from the cargo, lead plating and him constructions elements. After clearing of the sand from the preserved part of the ship hull with the help of a hydro injector the video and photo documentation was carried out. As a result of these works, large-scale photo mosaic of the object and its 3D-model were made. The condition of the wooden hull is excellent, the technological holes, connections, bronze and iron nails are preserved. Outside of Ukraine several shipwrecks of the same period are attested. The best studied are the following: shipwreck of the 3rd century BC at Grand Congloue, France; the Mazotos shipwreck of the 4th century BC in Cyprus; the Porticello shipwreck of the end of the 5th or beginning of the 4th century BC in Italy; the Alonnisos shipwreck from the end of the 5th century BC, Greece; the Kyrenia shipwreck from the end of the 4th — beginning of the 3rd centuries BC in Cyprus. In the Black Sea, in 2011 a shipwreck from the end of the 4th — beginning of the 3rd centuries BC near Eregli, Turkey (ancient Herakleia Pontica) was discovered by a deep-sea expedition of the research vessel «Nautilus» under the direction of Michael Brennan at a depth of 101 m. Most of the known merchant ships of this period were small, ranging from 12 to 17 m (table). Boris Peters provides a reconstruction sketch of the Lake Donuzlav ship of the late 4th — early 3rd centuries BC. It is almost identical to the reconstruction of the Kyrenia merchant ship, based on its hull which was preserved by 75 %, The replica named «Kyrenia 2» was built and made several voyages. It can be assumed that the Kinburn Spit ship found in 2018 was of similar appearance but further research will provide more detailed information.
In this study, it was aimed to determine the species composition and marine biodiversity on and around the TCSG-132 shipwreck, which was located between 22.4 and 24.8 m depths in the coasts of Gökçeada Island. In this context, aquanauts regularly conducted SCUBA-equipped dives between October 2018 and September 2019. Visual counting techniques (transect and point-count (quadrat)), photo shoots and video recordings were used to obtain the data during the dives. As a result of the study, 12708 individuals from 28 different species belonging to 19 families were recorded. Among these, 15 species were determined to have economic importance. The most commonly observed species were bogue (Boops boops, 44.55%), damselfish (Chromis chromis, 26.44%) and blotched picarel (Spicara maena, 15.50%). In conclusion, TCSG-132 shipwreck has been found to serve as an important artificial reef for marine species and to provide living, sheltering, spawning, feeding and conservation opportunities for marine species.
In this study, loggerhead sea turtle Caretta caretta (Linnaeus 1758) was observed for the first time around the shipwreck of coast guard boat in Ördek Yalağı located at Gökceada Island, North Aegean Sea. The shipwreck is at a depth of 24.8 m. The loggerhead sea turtle Caretta caretta was recorded exactly on the ground and 2 m away from the ship on the shore side of the ship. In this study, Caretta caretta was recorded for the first time in this water depth and around a shipwreck that was used as an artificial reef for Turkish waters.
Telepresence-enabled exploration of deep sea environments has developed over the past 30 years, providing access to archaeologists, scientists, and the general public to sites otherwise inaccessible due to depth. Pioneered through the inception of the JASON Project in the late 1980 s, telepresence missions have expanded to two dedicated ships of exploration, NOAA Ship Okeanos Explorer and exploration vessel Nautilus, and has been implemented on a series of opportunistic missions on other vessels. This paper chronicles the history of the use of telepresence for the exploration of shipwrecks in deep water as well as how this capability has allowed the public to engage with such missions. Broadening the scope of who can explore the deep sea, telepresence has also expanded what is observed and documented in the deep, which speaks to humanity’s use of the maritime world and an archaeology of discard through our material disposed of into the deep sea. © 2018 Springer Science+Business Media, LLC, part of Springer Nature
RESPONSE OF DAVID PARHAM TO SEAN KINGSLEY’S COMMENTS ON HIS REVIEW OF SEAN KINGSLEY’S FISHING AND SHIPWRECK HERITAGE: MARINE ARCHAEOLOGY’S GREATEST THREAT? (BLOOMSBURY, 2016) - David Parham
This section of the book examines some fields where collapses often occur, listed in a very approximate order of complexity and lethality, with the idea of building up the understanding of what causes collapses by means of a series of practical examples. We start with the simplest case: that of the breakdown of everyday things, to arrive at what we may consider as the ultimate collapse: the death of Gaia, the Earth’s ecosystem. Each case examined offers the occasion for a discussion of the theory behind the collapse of complex systems. There doesn’t seem to exist a single theoretical framework that explains Seneca’s concept that “ruin is rapid,” but we may see a unifying factor in the “Maximum Entropy Production” principle. Whenever a system can find a way to go to its ruin, it will do so rapidly, as Seneca had already understood two thousand years ago.
Currently researchers are advancing unmanned surface vehicle (USV) for bathymetry and hydrography applications. The idea of USV was introduced to avoid the risk and danger of personnel on the water terrain. When it comes to shallow water bathymetry mapping most method has the limitation to measure terrain which less than 1 meter deep. Commonly USV uses sonar depth sensor to measure the water depth yet it has a minimum range which it can measure. In this paper, the USV has been equipped with an additional mechanical bar measurer to be used on the very shallow part of the water bodies. By lowering and measuring the angle of the bar respect to the boat's draft, the depth of the very shallow water can be obtained. The cases of the rocking of the boat are also being considered by measuring the roll and pitch and implement forward kinematic method for depth correction.
Fishing and Shipwreck Heritage: marine archaeology’s greatest threat? By Kingsley Sean A . 220mm. Pp 176, 16 b&w ills. Debates in Archaeology Series, Bloomsbury Academic, London, 2016. ISBN 9781472573605. £45 (hbk). - Dave Parham
Schema, broadly defined, is a representative framework or plan. After the 2010 Deepwater Horizon oil spill, the Natural Resource Damage Assessment process began and the scientific community flocked to the Gulf of Mexico to study the spill’s impacts. Unfortunately, shipwrecks and other submerged cultural resources were largely ignored. Through Federal and academic partnerships and contracts funded by the Bureau of Ocean Energy Management, a multidisciplinary team of scientists was assembled to examine the spill’s impacts on deepwater shipwrecks and their resident microbial communities. Presented here is the project’s “schema”: its design and objectives, site selection criteria, and development through partnerships.
In 2000, a major expedition for deepwater archaeology was conducted by the Institute for Exploration in the Black Sea along the northwestern coast of Turkey from the Bosporus to the Turkish seaport of Sinop. A complementary land-based expedition will be reported upon elsewhere. The 2000 underwater expedition had three research objectives: to search for evidence of human habitation prior to major flooding of the Black Sea that researchers predicted occurred some 7,500 years ago; to investigate a deepwater shipping route; and to search for ancient wooden ships in the sea's anoxic bottom waters. Research methods included the use of a phased-array side-scan sonar, a towed imaging sled, and a small remotely operated vehicle (ROV) to collect deep-sea survey data. Three shipwrecks and a probable site reflecting human habitation prior to the proposed flooding event were located at depths around 100 m. One additional shipwreck was found within the anoxic layer at a depth of 324 m. The ship found within the anoxic layer was intact, in a high state of preservation, and dated to the Byzantine period of 450 A.D.
The protection and management of Underwater Cultural Heritage (UCH) is a challenging topic, as no single statute comprehensively protects UCH from all human activities. This paper provides an analysis of existing laws protecting UCH on the U.S. Outer Continental Shelf (OCS), identifies gaps in protection, and recommends legislative changes to address any gaps. The results of the analysis indicate a need for legislative changes to better protect UCH, including proposals to amend the Archaeological Resources Protection Act and/or the National Marine Sanctuaries Act.
The August 2007 expedition to the Black Sea continued a multiyear project designed to locate and study ancient shipwrecks in deep water. The expedition revis-ited and investigated two shipwrecks, Sinop D (at 325 m depth off Sinop, Turkey) and Chersonesos A (at 135 m depth off Sevastopol, Ukraine). These wreck sites are good case studies for our research because they are located in different parts of the Black Sea, in anoxic and suboxic waters, respectively. Preliminary data reported here are from seawater samples taken from around the wrecks and a year-long collection of temperature, salinity, and pressure data. Trace-element data from the seawater samples are consistent with reported processes and values for the Black Sea. The oceanographic sensor data confi rm the stagnant nature of the anoxic water layer that has allowed for the high level of preservation of the Sinop D wreck site. We also dis-cuss the design and placement of two sets of experiments left in situ to characterize the decay rates of common materials found on ancient shipwrecks, including wood and metal. By providing ways to understand the chemical and physical processes that characterize different parts of the Black Sea water column, these wrecks are impor-tant sites for (1) determining the preservation potentials of cultural materials in deep water, and (2) informing the design of methodologies necessary to conserve them.
We evaluated the adequacy of an indicator of benthic community health to assess trawling disturbance by sampling epifauna at 6 sites subjected to variable fishing intensity in the Mediterranean: from no fishing, in an area associated to a marine reserve, to high fishing intensity, in trawling grounds. The proposed indicator is based on the biological traits composition of epifaunal species that determine vulnerability to trawling: mobility, fragility, position on substrata, average size and feeding mode. Five groups defined by the combination of these biological traits represented different levels of vulnerability to trawling. Results based on analysis of the relative abundance of these groups at each site showed that the biological traits significantly reflected ecosystem disturbance, with the less disturbed communities having the highest abundance of groups considered vulnerable to trawling. According to these findings a Trawl Disturbance Index (TDI) was proposed as a tool for fisheries managers to assess the ecosystem health.
Fishers have been complaining about the effects of bottom trawl gear on the marine environment since at least the 14th century. Trawl gear affects the environment in both direct and indirect ways. Direct effects include scraping and ploughing of the substrate, sediment resuspension, destruction of benthos, and dumping of processing waste. Indirect effects include post‐fishing mortality and long‐term trawl‐induced changes to the benthos. There are few conclusive studies linking trawling to observed environmental changes since it is difficult to isolate the cause. However, permanent faunal changes brought about by trawling have been recorded. Research has established that the degree of environmental perturbation from bottom trawling activities is related to the weight of the gear on the seabed, the towing speed, the nature of the bottom sediments, and the strength of the tides and currents. The greater the frequency of gear impact on an area, the greater the likelihood of permanent change. In deeper water where the fauna is less adapted to changes in sediment regimes and disturbance from storm events, the effects of gear take longer to disappear. Studies indicate that in deep water (>1000 m), the recovery time is probably measured in decades.
Marine protected areas (MPAs) potentially enhance the long-term sustainability of coastal fish resources that have been overexploited. The types and quality of habitats, both inside and outside the MPAs, may determine the likelihood of migration by fish to surrounding unprotected areas where spillover to fisheries occurs. We assessed whether MPAs enhanced catches of artisanal fisheries, using an experimental fishing study with the same fishing gear as that used by local fishers. This approach allowed us to test the hypothesis of increased catches along the borders of MPAs in comparison with those in other fishing grounds located at. medium and far distances from 3 Mediterranean MPAs: Tabarca Marine Reserve, Carry-le-Rouet Marine Reserve and Cerbere-Banyuls Marine Reserve. Surveys were clone over 2 homogeneous habitats (Posidonia oceanica meadow and sand), in 3 different seasons. Catches were significantly higher for some species near the borders of the MPAs when fishing on P. oceanica meadows, but not when fishing on sandy bottoms. The spillover effect appears to be limited by a lack of continuous Suitable habitat through the boundaries of the MPA. Some of the species that showed a significant response to protection and concurrent higher catches near the MPA borders, such as Dentex dentex, Mullus surmuletus, Phycis phycis, Sciaena Umbra and Scorpaena porcus, are target species of artisanal fisheries. Although we found that the spatial scale of the spillover-induced density gradient was localized, it was sufficient to provide local benefits to artisanal fisheries. We conclude that spillover effects are not a universal consequence of siting MPAs in temperate waters and that they are related to the distribution of habitats inside and around MPAs.
The management of fisheries resources in the northwestern Mediterranean is traditionally centralized and developed within the framework of coastal states and European Union common policies. In general, it has not been sufficiently effective in reversing the declining situation of fisheries resources and fishers in this region. This paper discusses the feasibility of moving away from a top-down approach in fisheries management towards a more participative and convergent mode of governance in the region. More specifically, the study focuses on MPAs as a fisheries management tool and evaluates their current establishment and management system in the French Mediterranean as a case study for the region. A brief review of the experiences on fisheries and MPA management in the Philippines is also presented to obtain insights on bottom-up and collaborative management approaches. Finally, possible opportunities for adopting a more decentralized and coordinated approach in fisheries management within the French socio-political system, and possibly in the northwestern Mediterranean region, are discussed. These include the existence of fishing community organizations in the region, such as the prud'homies in France and cofradias in Spain, starting with management strategies that are simpler to enforce and more acceptable to direct users, e.g., fishery reserves, and exploring co-management arrangements to manage fisheries at ecologically meaningful but operationally manageable scales as has been proposed by some development organizations. However, effective changes in the system would require major national policy and institutional reforms, social preparation and organizational strengthening which would take time and resources.
Continued exploration of the coastal area of the southern Black Sea off Sinop and Ereğli, Turkey in 2011 further documented the transition zone along the oxic/anoxic interface. Push cores collected with an ROV in sediments underlying the oxic, suboxic, and anoxic waters were analyzed for geochemistry, meiofauna, and microbiology to help characterize this transition zone. During the course of side-scan sonar surveys, nine shipwrecks were located in various states of preservation, all within 100-115 m depth and ranging from the 4th century B.C. to the early 20th century. Many of these wrecks have wooden components well preserved due to the influences of the anoxic waters being washed up along the shelf by internal waves. However, a number of these sites have also been heavily damaged by bottom trawling along the seabed up to the shelf break, highlighting the drastic threat such activities pose to archaeological sites.
Bottom trawling is a non-selective commercial fishing technique whereby heavy nets and gear are pulled along the sea floor. The direct impact of this technique on fish populations and benthic communities has received much attention, but trawling can also modify the physical properties of seafloor sediments, water–sediment chemical exchanges and sediment fluxes. Most of the studies addressing the physical disturbances of trawl gear on the seabed have been undertaken in coastal and shelf environments, however, where the capacity of trawling to modify the seafloor morphology coexists with high-energy natural processes driving sediment erosion, transport and deposition. Here we show that on upper continental slopes, the reworking of the deep sea floor by trawling gradually modifies the shape of the submarine landscape over large spatial scales. We found that trawling-induced sediment displacement and removal from fishing grounds causes the morphology of the deep sea floor to become smoother over time, reducing its original complexity as shown by high-resolution seafloor relief maps. Our results suggest that in recent decades, following the industrialization of fishing fleets, bottom trawling has become an important driver of deep seascape evolution. Given the global dimension of this type of fishery, we anticipate that the morphology of the upper continental slope in many parts of the world’s oceans could be altered by intensive bottom trawling, producing comparable effects on the deep sea floor to those generated by agricultural ploughing on land.
The gravel sediment habitat on the northern edge of Georges Bank (East coast of North America) is an important nursery area for juvenile fish, and the site of a productive scallop fishery. During two cruises to this area in 1994 we made photo-graphic transects at sites of varying depths that experience varying degrees of disturbance from otter trawling and scallop dredging. Differences between sites were quantified by analyzing videos and still photographs of the sea bottom. Videos were analyzed for sediment types and organism abundance. In the still photos, the percentages of the bottom covered by bushy, plant-like organisms and colonial worm tubes (Filograna implexa) were determined, as was the presence/absence of encrusting bryozoa. Non-colonial organisms were also identified as specifically as possible and sediment type was quantified. Significant differences between disturbed and undis-turbed areas were found for the variables measured in the still photos; colonial epifaunal species were conspicuously less abundant at disturbed sites. Results from the videos and still photos were generally consistent although less detail was visible in the videos. Emergent colonial epifauna provide a complex habitat for shrimp, polychaetes, brittle stars and small fish at undisturbed sites. Bottom fishing removes this epifauna, thereby reducing the complexity and species diversity of the benthic community.
Recent advances in deep-submergence technology as well as the discovery of a growing number of cultural sites in the world’s
oceans have led to the emergence of a new field of research, Archaeological Oceanography. The purpose of this paper is to
review the short history of this newly emerging field of research including the evolution of remotely operated vehicle systems,
various examples of their application in field programs, and the challenges future programs face in gaining access to the
resources and tools needed to carry out such work in the great depths and remote locations of the world where submerged cultural
resources may be found.
Marine protected areas (MPAs) are considered as an effective tool in marine coastal management, and considered able to enhance local fisheries through adult fish spillover. Indirect evidence of fish spillover could be obtained by horizontal gradients in fish abundance. To address this question, the existence of gradients of fish abundance and biomass across marine reserve boundaries was assessed in six Mediterranean MPAs using underwater visual censuses performed at various distances from the core of the MPA, in integral reserve (IR), to buffer zone (BZ) and fished areas. A reserve effect was evidenced with higher values of fish species richness (×1.1), abundance (×1.3), and biomass (×4.7) recorded inside MPAs compared to adjacent fished areas. Linear correlations revealed significant negative gradients in mean fish biomass in all the reserves studied after the effect of habitat had been removed, whereas negative gradients in abundance were less conspicuous. Generalized additive models suggested two main patterns of biomass gradients, with a sharp decrease at the IR–BZ boundary or at the BZ–fished area boundary. It was estimated that fish spillover beneficial to local fisheries occurred mostly at a small spatial scale (100s of metres). The existence of regular patterns of negative fish biomass gradients from within MPAs to fished areas was consistent with the hypothesis of adult fish biomass spillover processes from marine reserves and could be considered as a general pattern in this Mediterranean region.
Sediment profile imagery (SPI) was evaluated for the assessment of otter trawling impacts on the seabed. This technique allows the imaging of the topmost sediment layers in profile, including the sediment–water interface. Two areas in the Aegean Sea were investigated in time series, each with control and impact areas: a commercial fishing lane with soft sediments at approximately 200 m depth and an experimentally trawled lane with harder maerly sediments at approximately 80 m depth. In total, 158 images were taken at the deep ground and 124 at the shallow ground. A number of measurements were taken from each image, leading to estimates of comparative penetration and small-scale seabed surface roughness. In addition, a large number of surface and subsurface attributes were noted in the images to form the basis of a multivariate analysis. Results indicated that penetration and roughness by themselves were not very good indicators, although roughness was a better indicator particularly in coarse sediments. The major reason for this is that the measurements alone (in particular roughness) do not distinguish between biological and anthropogenic disturbance. The multivariate analysis combining the measurements with the attributes was a good indicator in investigating trawling impacts in coarse sediments, where the lack of good penetration can be compensated by the view over the sediment surface, where more attribute-type data can be gathered. The SPI sampling window gives a relatively small imaged sample in comparison to other imaging techniques (side scan sonar, video, etc.) and in a heterogeneous environment, the more the replicates, the more reliable the method will be. A tiered imaging approach is recommended where more than one methodology is used.
Towed bottom-fishing gears are thought to constitute one of the largest global anthropogenic sources of disturbance to the seabed and its biota. The current drive towards an ecosystem approach in fisheries management requires a consideration of the implications of habitat deterioration and an understanding of the potential for restoration. We undertook a meta-analysis of 101 different fishing impact manipulations. The direct effects of different types of fishing gear were strongly habitat-specific. The most severe impact occurred in biogenic habitats in response to scallop-dredging. Analysis of the response of different feeding guilds to disturbance from fishing revealed that both deposit- and suspension-feeders were consistently vulnerable to scallop dredging across gravel, sand and mud habitats, while the response of these groups to beam-trawling was highly dependent upon habitat type. The biota of soft-sediment habitats, in particular muddy sands, were surprisingly vulnerable, with predicted recovery times measured in years. Slow-growing large-biomass biota such as sponges and soft corals took much longer to recover (up to 8 yr) than biota with shorter life-spans such as polychaetes (<1 yr). The results give a possible basis for predicting the outcome of the use of different fishing gears in a variety of habitats with potential utility in a management context.
The gravel sediment habitat on the northern edge of Georges Bank (East coast of North America) is an important nursery area for juvenile fish, and the site of a productive scallop fishery. During two cruises to this area in 1994 we made photographic transects at sites of varying depths that experience varying degrees of disturbance from otter trawling and scallop dredging. Differences between sites were quantified by analyzing videos and still photographs of the sea bottom. Videos were analyzed for sediment types and organism abundance. In the still photos, the percentages of the bottom covered by bushy, plant-like organisms and colonial worm tubes (Filograna implexa) were determined, as was the presence/absence of encrusting bryozoa. Non-colonial organisms were also identified as specifically as possible and sediment type was quantified. Significant differences between disturbed and undisturbed areas were found for the variables measured in the still photos; colonial epifaunal species were conspicuously less abundant at disturbed sites. Results from the videos and still photos were generally consistent although less detail was visible in the videos. Emergent colonial epifauna provide a complex habitat for shrimp, polychaetes, brittle stars and small fish at undisturbed sites. Bottom fishing removes this epifauna, thereby reducing the complexity and species diversity of the benthic community.
An innovative approach with side-scan sonar was implemented to observe directly during towing operations the behaviour and the performance of hydraulic dredge, Rapido trawl, and two types of Mediterranean bottom trawls. The innovative aspect of the current paper is that a side-scan sonar was used alongside fishing operations when towing was in progress. Based on available literature, the type and level of the physical impact assessed were used to infer biological and ecological consequences caused by the fishing gear. The sonar used in real time can be applied to a wide range of research and management issues, such as the fishing gear impact on benthic ecosystems and the in situ fishing gear performance. We demonstrated that gear type and rigging, together with environmental conditions, are the main factors affecting the disturbance caused by fishing. Hydraulic dredges scrape the surface of the substratum and dig into it by resuspending large amounts of sediment. Rapido trawls used in muddy areas for common sole (Solea solea) dig deeper into the sediment, making furrows up to 10–13 cm deep. The most evident physical effects of trawling were the furrows produced by the otterboards, while other parts of the trawl created only faint marks.
Three complementary seabed characterization tools with different spatial resolution were used to locate a research site and to assess physical effects of experimental otter trawling in the Barents Sea: an acoustic seabed classification system (RoxAnn), sidescan sonar and a video-sledge. The marine protected area (MPA) around Bear Island was chosen as it offered unfished reference sites. The area was topographically complex which resulted in certain challenges for choice of the experimental site due to the requirements of representativity and homogeneity and suitable sampling substrate. Systematic waylines with RoxAnn gave broad- scale patterns of bottom conditions, the more informative sidescan revealed topographic reliefs, whilst detailed information on sediment composition and small-scale seabed features was provided by the video-sledge. Accurate positioning of towed gears (trawl, sidescan and video-sledge) ensured unbiased data acquisition. Trawl doors and rockhopper gear created furrows that were visible by sidescan sonar and video. Intensive trawling also caused changes in the acoustic properties by increasing roughness and decreasing hardness. Results are consistent with a possible resuspension of the sediment and a homogenizing effect from the trawl doors and ground gear ploughing the area. The suitability and advantages of using spatially overlapping tools in trawl impact studies are discussed.
Odyssey Marine Exploration's Atlas Shipwreck Survey Project in the western English Channel and Western Approaches has recorded 267 shipwrecks across 4,725 square nautical miles. A high density of the sites displays evidence of detrimental impacts from the deep-sea fishing industry, predominantly trawler, scallop dredge and gill net fishing activities. This report summarizes the effects of deep-sea fishing on all shipwrecks in the Atlas zone. The wreck of HMS Victory, a first-rate Royal Navy warship lost in October 1744, is examined in particularly focused detail. Three main sources are utilized and compared: side-scan sonar analysis, visual site reconnaissance of all targets using a Remotely-Operated Vehicle, and a statistical analysis of fishing in relation to wreck locations based on 73,385 VMS (Vessel Monitoring System) aerial sightings and 838,048 satellite observations of fishing vessels operating inside Odyssey's shipwreck survey zone between 1985 and 2008. This research leads to the conclusion that the shipwrecks in the study zone have been, and continue to be, targeted, inad- vertently disturbed and/or systematically exploited for deep-sea fishing due to their nature as nutrient-rich biological oases and shelter for an abundance of fish populations. Whereas steel wrecks display a level of expected structural robustness in many cases, the majority of the archaeologically significant wooden sites are at high risk, some extremely so. Largely isolated beyond the parameters of national and international legislative protection, the small percentage of surviving sites that constitute unique cultural heritage requires attention and a plan for preserving the archaeological data that can still be secured from them. This report is intended to assess methodically and statistically a problem that is unquantified and poorly recognized to date within marine archaeology. The intent is not to cast blame on fisheries. Rather, it is to present the factual data in order to develop plans for taking into account all different user groups of underwater cultural heritage, particularly the crucial role fishermen serve society and the economy. This report is rooted on the principle that the relationships between fishermen, ecologists, archaeolo - gists, historians, salvors, sport divers, heritage managers and marine construction companies working legally in the study region are, and must remain, respectfully symbiotic. These results reflect specifically the conditions in one geographical area, but bring to the fore an issue that should be studied worldwide to help develop a rational and effective approach for protecting and preserving deep-sea maritime heritage. © Odyssey Marine Exploration, 2009
In October 1974, a sector scanning sonar adapted for operation in side-scan mode was used to examine a channel dredged in
1971 within the sandwave field at Longsand Head (Outer Thames Estuary). Trials of the system were successful. The range and
resolution of the records obtained were comparable with those of EG & G side-scan sonar but the provision of automatic gain
control permitted the detection of seabed features which had hitherto been unresolved by side-scan sonar.
Resurvey of a channel dredged through the sandwave field off Longsand Head showed that sections of the major sandwaves removed
by dredging had shown only a limited tendency to reform in the 3-year period since the close of dredging operations. A system
of dunes (5 m wavelength) had developed in the fine infill material which covers the floor of the channel. Intermittent noise
signals due to sediment movement were recorded by the modified scanner system during each survey leg and provide some qualitative
impression of the patchiness of sediment movement on sandwave crests.
Tracks of three types of fishing gear in bottom sediments were observed from a submersible in Chaleur Bay (Gulf of St. Lawrence). Tracks left by past otter trawling activities covered at least 3% of the bottom by area and were considered to have been made by trawl doors.Shallow tracks made by inshore and offshore scallop dredges during the course of the study could be distinguished from each other and from trawl tracks.Scallop dredging lifts fine sediments into suspension, buries gravel below the sand surface, and overturns large rocks embedded in the sediment, appreciably roughening the bottom. The inshore Alberton dredge is inefficient, dumping its contents back onto bottom at intervals during the tow.Dredging causes appreciable lethal and sublethal damage to scallops left in the track, this damage being greatest on rough bottom. Incidental mortalities to scallops with an offshore dredge of at least 13–17% per tow are of the same order of magnitude as estimates of harvesting efficiency made in earlier studies.Predatory fish and crabs were attracted to the dredge tracks within 1 hr of fishing and were observed in the tracks at densities 3–30 times those observed outside the tracks.
An important first step in marine spatial planning and ecosystem-based management efforts is the creation of benthic habitat maps that allow scientists and managers to understand the distribution of living and non-living resources on the seafloor. However, the location of boundaries between and composition of habitats is highly dependent on the approach taken to integrate abiotic and biotic information. The purpose of this study was to test “top-down” and “bottom-up” approaches for integrating physical and biological data derived from commonly used sub-tidal benthic mapping tools to create a habitat map compatible with the US Coastal and Marine Ecological Classification Standard (CMECS). We found that a top-down framework, where we tested for differences in macrofauna assemblages among side scan sonar facies, defined two broad-scale and general habitats. Using the bottom-up approach, where patterns in abiotic and biotic variables were examined with multivariate statistics (BEST, LINKTREE, ANOSIM, SIMPER), we generated seven biotopes based on the macrofauna abundance, percent sand, water depth, and backscatter standard deviation that corresponded well to, but provided more fine-scale detail than the top-down habitats. We were able to use the statistical relationship between abiotic variables and macrofauna assemblages in the LINKTREE to predict the spatial distribution of assemblages over ∼50% of the study area. We created a local catalogue of biotopes specific to our study area that contributes to the CMECS library. In addition, we were able to fully map CMECS Geoform, Surface Geology, and Biotic Cover Components. This mapping effort represented real progress toward reconciling the “data density mismatch” between physical and biological mapping methods, and it provided further evidence that using a bottom-up methodology preserves species–environment relationships.
The abundance of some marine fish species are correlated to the abundance of habitat-forming benthic organisms such as sponges and corals. A concern for fisheries management agencies is the recovery of these benthic invertebrates from removal or mortality from bottom trawling and other commercial fisheries activities. Using a logistic model, observations of available substrate and data from bottom trawl surveys of the Aleutian Islands, Alaska, we estimated recovery rates of sponges and corals following removal. The model predicted the observed sponge and coral catch in bottom trawl surveys relatively accurately (R2=0.38 and 0.46). For sponges, the results show that intrinsic growth rates were slow (r=0.107yr−1). Results show that intrinsic growth rates of corals were also slow (r=0.062yr−1). The best models for corals and sponges were models that did not include the impacts of commercial fishing removals. Subsequent recovery times for both taxa were also predicted to be slow. Mortality of 67% of the initial sponge biomass would recover to 80% of the original biomass after 20 years, while mortality of 67% of the coral biomass would recover to 80% of the original biomass after 34 years. The modeled recovery times were consistent with previous studies in estimating that recovery times were of the order of decades, however improved data from directed studies would no doubt improve parameter estimates and reduce the uncertainty in the model results. Given their role as a major ecosystem component and potential habitat for marine fish, damage and removal of sponges and corals must be considered when estimating the impacts of commercial bottom trawling on the seafloor.
As archaeologists find new ways to pull precious data from wrecks, they are squaring off against those salvaging ships for profit.
In a field study conducted in Austin, Texas, a greater number of Pseudacteon tricuspis, a species-specific phorid fly parasitoid of the red imported fire ant (RIFA), were collected at worker corpses than alate corpses. Neither sex of fly discovered corpses more frequently than the other.
Maerl beds are mixed sediments built by a surface layer of slow-growing, unattached coralline algae that are of international conservation significance because they create areas of high biodiversity. They are patchily distributed throughout Europe (to 30 m depth around the British Isles and to 120 m depth in the Mediterranean) and many are affected by towed demersal fishing. We report the effects of Newhaven scallop dredges on a previously unfished maerl bed compared with the effects on similar grounds that have been fished commercially in the Clyde Sea area, Scotland. Sediment cores were taken to assess the population density of live maerl thalli prior to scallop dredging on marked test and control plots. These plots were then monitored biannually over a four-year period. Live maerl thalli were sparsely distributed at the impacted site, and experimental dredging had no discernible effect on their numbers. The previously unfished ground had dense populations of live maerl and scallops (both Aequipecten opercularis and Pecten maximus). While counts of live maerl remained high on the control plot, scallop dredging led to a >70% reduction with no sign of recovery over the subsequent four years. The vulnerability of maerl and associated benthos (e.g., the delicate bivalve, Limaria hians) is discussed in relation to towed demersal fishing practices. 2000 International Council for the Exploration of the Sea Key words: benthos, ecosystem effects, long-term impact, maerl beds, scallop dredging.
1. Marine reserves are widely used for conservation and fisheries management. However, there is debate surrounding the speed of population recovery inside reserves and how recovery differs among species. Here, we determine how reserve effectiveness in enhancing fish density changes with reserve age. We also examine how the effects of protection vary between fished and non-fished species and among species of different body sizes, which we use as a proxy for life history and ecology.
2. We meta-analysed over 1000 ratios of fish densities (inside : outside reserves) taken from reserves of 1–26 years old from around the world.
3. Overall, older reserves were more effective than younger reserves, with fish densities increasing within reserves by ∼5% per annum relative to unprotected areas. Reserves older than 15 years consistently harboured more fish compared with unprotected areas; younger reserves were less reliably effective.
4. Large, fished species responded strongly and positively to protection in old (>15 years) and, unexpectedly, in new and young (≤10 years) reserves. Small, fished species and non-fished species of all sizes showed weaker responses to protection that did not vary predictably with reserve age.
5. We expected large fish to respond more slowly to protection than smaller species. We also expected small species to decline after large fish had recovered (i.e. trophic cascades). Neither prediction was supported.
6. Synthesis and applications. Our meta-analyses demonstrate that, globally, old reserves are more effective than young reserves at increasing fish densities. Our results imply that reserves should be maintained for up to 15 years following establishment, even if they initially appear ineffective. If protection is maintained for long enough, fish densities within reserves will recover and such benefits will be particularly pronounced for large, locally fished species.
Artificial reefs are spatially complex habitats and serve as good model systems to study patterns of community succession and the response of epibiota to environmental clines over small spatial scales. Here, we quantified spatial heterogeneity in community composition and diversity of fouling communities across a number of environmental gradients that included water depth, surface orientation of habitats, exposure to currents, and shelter. Assemblage structure was quantified by spatially replicated photo transects on a recently scuttled large navy ship off the East Australian coast, lying in 27 m of water. A rich assemblage of epifauna had colonized the wreck within a year, dominated by barnacles, sponges and bryozoans. Community structure varied significantly over small spatial scales of meters to tens of meters. Depth, surface orientation and exposure were the major environmental drivers. Assemblages were substantially less diverse and abundant on the deepest (23 m near the seafloor) part of the hull with residual antifouling paint, on sheltered surfaces inside the wreck, and on the sediment-laden horizontal surfaces. Overall, the wrecks’ habitat complexity corresponds with small-scale heterogeneity in the fouling communities. This study supports the notion that wrecks enhance local diversity and biomass within the habitat mosaic of their location, and habitat complexity may be an important mechanism for this, as demonstrated by the large spatial variability in the assemblages documented here.
Archaeological oceanography and environmental characterization of shipwrecks in the Black Sea Geology and Geoarchaeology of the Black Sea Region: Beyond the Flood Hypothesis
- M L Brennan
- R D Ballard
- Croff Bell
- K L Piechota
- D Buynevich
- I Yanko-Hombach
- V Gilbert
- A Martin
Brennan, M.L., Ballard, R.D., Croff Bell, K.L., Piechota, D., 2011. Archaeological oceanography and environmental characterization of shipwrecks in the Black Sea. In:
Buynevich, I., Yanko-Hombach, V., Gilbert, A., Martin, R.E. (Eds.), Geology and
Geoarchaeology of the Black Sea Region: Beyond the Flood Hypothesis. Geological Society of America Special Paper 473, pp. 179-188. http://dx.doi.org/10.1130/2011.
2473(11).
Circular No. 37/1 of 2006-2008 Fishing Year Regulating Commercial Fishing in Seas and Inland Waters
Koruma ve Kontrol Genel Müdürlüğü (KKGM), 2006. Circular No. 37/1 of 2006-2008
Fishing Year Regulating Commercial Fishing in Seas and Inland Waters. Koruma ve
Kontrol Genel Müdürlüğü, Ankara, Turkey (bhttp://www.kkgm.gov.tr/regulation/
circular/37-1.htmlN. Accessed December 2009).
Convention on the Protection of the Underwater Cultural Heritage UNESCO http
UNESCO, 2001. Convention on the Protection of the Underwater Cultural Heritage
UNESCO http://portal.unesco.org/en/ev.php-URL_ID=13520&URL_DO=DO_
TOPIC&URL_SECTION=201.html (6 November 2015).
Abundance and Size of the sea Scallop Population in the Mid-Atlantic Bight
- J H Walker
Walker, J.H., 2013. Abundance and Size of the sea Scallop Population in the Mid-Atlantic
Bight (Master's Thesis) University of Delaware, Newark, DE.
Deepwater archaeology of the Black Sea: the
- Further Reading
- R D Ballard
- F T Hiebert
- D F Coleman
- C Ward
- J S Smith
- K Willis
- B Foley
- K Croff
- C Major
- F Torre
Further Reading
Ballard, R.D., Hiebert, F.T., Coleman, D.F., Ward, C., Smith, J.S., Willis, K., Foley, B., Croff, K.,
Major, C., Torre, F., 2001. Deepwater archaeology of the Black Sea: the 2000 season at
Sinop, Turkey. Am. J. Archaeol. 105, 607-623.
Archaeological oceanography
- Brennan