On potential use of historical perspectives in
Swedish marine management
, Oscar Törnqvist2
, Camilla Novaglio3
, Gustav Kågesten2
, Lars-Ove Loo5
and Ruth Thurstan6 RISE Report 2021: 10
On potential use of historical perspectives in
Swedish marine management
, Oscar Törnqvist2
, Camilla Novaglio3
, Gustav Kågesten2
, Lars-Ove Loo5
and Ruth Thurstan6
1RISE- Research Institutes of Sweden, Sweden 2Geological Survey of Sweden (SGU), Sweden
3Institute for Marine and Antarctic Studies, University of Tasmania, and Centre for
Marine Socioecology, Australia
4National Oceanic and Atmospheric Administration (NOAA), the USA 5University of Gothenburg, Sweden
6University of Exeter, the UK
Rapporten har tagits fram på uppdrag av Havs- och vattenmyndigheten. Rapportförfattarna ansvarar för innehållet och slutsatserna i rapporten. Rapportens innehåll innebär inte något ställningstagande från Havs- och vattenmyndighetens sida. Cover illustration: Swedish west coast when early settlers arrived~ 10 000 years ago, illustrated by Maria Eggertsen
Coastal seas have gone through dramatic transformations over the past millennia. Many changes have been driven by human activities. Current coastal monitoring and reference conditions used in policy are however in the scale of decades. This short perspective affects restoration goals and current understanding of the full potential of more sustainable use. This report summarizes the outcome of a pilot study on if, and how, longer historical perspectives of the seas may be of use in a Swedish coastal management context. Through contacts with experts in a range of scientific disciplines, literature searches and workshops, the report aims at providing a point of departure for further in-depth investigations. The report is not a comprehensive review, but rather provides examples of records available, research performed and suggests potential research themes for the future. It is found that there are ample opportunities to use a wide range of historical records from Swedish coasts for various management applications. There are also coastal policy applications that already are informed by historical perspectives, both international and Swedish, that may merit from further investigations. Based on the general interest by marine management practitioners in what historical applications may bring to contemporary management, international collaboration may provide leverage for action through exchange of experiences and comparisons of historical records.
Keywords: marine historical ecology, marine environmental history, Sweden, Kattegat, Skagerrak, the Baltic sea
RISE Research Institutes of Sweden AB RISE Report 2021: 10
ISBN: 978-91-89167-92-6 Göteborg 2021
This work is, except where otherwise noted, licensed under CC BY 4.0. To view a copy of this license, visit https://creativecommons.org/licenses/by/4.0
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ContentAbstract 3 Content 4 Preface 5 Acknowledgements 6
Summary and recommendations 9
1 Background 11
2 Method 12
2.1 Limitations 13
3 Marine Environmental History and Marine Historical Ecology 14
4 Swedish records on oceans past 17
4.1 Archaeological records 17
4.2 Historical records 22
4.3 Ecological records 25
4.4 Summary and outlook 28
5 What may be interpreted from Swedish historical records? 30
5.1 Finds to cultural ecology: disentangling geography, climate and society 30 5.2 Interpreting bones to support ecological baselines 32
5.3 Identifying useful ecological indicators 33
5.4 Summary and outlook 36
6 How can historical perspectives be of use for coastal management? 38
6.1 South and Eastern Australia 41
6.2 The USA (west coast) 43
6.3 Summary and outlook 45
7 What is needed to utilize historical perspectives in coastal management?
Potential research themes 46
7.1 Commercially used fish 46
7.2 Marine mammals 49
7.2.1 Co-existence with abundant seals 49
7.2.2 Cetaceans and Swedish coastal seas 51
7.3 Ecosystem structure and function 53
7.4 Restoration 55
7.5 Expected outcome of marine historical research? 59
7.6 Summary and outlook for opportunities from international collaboration 62
Swedish funding for this work has been provided through the bilateral cooperation program coordinated by the Swedish Nature Protection Agency. The collaboration is based on the basis of a Memorandum of Understanding between the kingdom of Sweden and the state of California, USA.
A symbiotic collaboration on marine management between the Swedish Agency for Marine and Water Management (SwAM), the Geological Survey of Sweden (SGU), the National Oceanic and Atmospheric Administration (NOAA) and several Californian academic institutions has developed in recent years. The goal is to share experiences among governmental institutions, supported by academia, to the benefit of environmental management and policy in the marine field.
As responsible for Swedish fisheries management as well as marine environmental management, SwAM is currently in the process of developing a more holistic and genuinely ecosystem-based management approach. The main purpose is to bridge between fisheries- and environmental management. In this formative phase SwAM, seeks to better understand if and how such ecosystem-based management can be assisted by science on ocean past, that is, the historical state and functioning of marine ecosystems. This topic has been agreed upon as a new area of collaboration between SwAM and Californian partners.
The conclusions drawn represent the views of the author and not necessarily the Swedish Agency for Marine and Water Management (SwAM).
This report spans over a wide range of scientific disciplines, data sources and methods. Therefore, the authors want to express great gratitude to all experts who have taken the time to share their knowledge.
The authors also want to express gratitude to the project group at SwAM (Linus Hammar, Ingela Isaksson, Mårten Åström, Peter Funegård) and other people that has provided input to the pilot project (Peter Göransson, Thomas Dahlgren, Kristina Bergman, Lance Morgan and Chris Caldow).
The work has been funded by SwAM (Dnr 2361-20) within the Sweden-California bilateral cooperation program for environment and climate, coordinated by the Swedish Nature Protection Agency NV-00504-20.
rekommendationer (in Swedish)
Denna rapport presenterar resultaten av ett pilotprojekt med den övergripande frågeställningen: Hur kan kunskap om havets tidigare, mer naturliga, ekosystem tas tillvara för att stärka ekosystembaserad förvaltning?
Havet har förändrats väldigt mycket sedan de första människorna bosatte sig längs kusten för tusentals år sedan: förlust av stora fiskar, kraftig nedgång av ostron, däggdjur och fåglar, ändrad utbredning av livsmiljöer på botten, med mera. Med tiden har minnet gått förlorat av det som en gång var naturligt. Det medför en förändrad referenspunkt, eller baslinje – något som dessutom har accelererat över tid. I samtida kustförvaltning sträcker sig referensförhållanden i bästa fall bara några decennier bakåt. Detta kortsiktiga perspektiv innebär en kunskapsbrist som medför förlorade möjligheter att både återställa mer av det som gått förlorat och förstå fördelarna det skulle ge, samt påverkar förutsättningarna för att identifiera mer långsiktigt hållbara nivåer av mänsklig påverkan från ökad kunskap om historiens hav.
Historisk forskning om havet syftar till att rekonstruera det förflutna genom att använda tvärvetenskapliga metoder och källor av olika slag. Pilotprojektet har kommit fram till att det finns en stor mängd material att studera för att undersöka tillstånd, orsaker och konsekvenser av förändringar som skett i svenska hav under de senaste 10 000 åren, den ungefärliga tidpunkten för bosättningar längs kusten i södra Sverige. Materialet omfattar allt från spridda benrester och andra arkeologiska fynd, historiska dokument av olika slag, till alltmer noggrann dokumentation.
Vissa historiska källor för svenska hav kan vara unika i ett internationellt perspektiv (som bottenfaunaundersökningar i slutet av 1800-talet) och många erbjuder högkvalitativa data (som skatteregister) och obrutna tidsserier för över 10 000 år (sedimentkärnor). För en del insamlat material blir snart vissa former av analys omöjliga på grund av nedbrytning (organiskt material i form av ben). Det är också essentiellt att förstå det kulturella sammanhanget när man använder historiskt material som bas för indikatorer, och applicera källkritik och utvärdera materialets representativitet.
Pilotprojektet visar även tydligt att en fördjupad analys av tillgängligt historiskt material kan ge input till ekosystembaserad förvaltning. Ett exempel är möjligheten att särskilja naturliga variationer från mänsklig påverkan. Ett annat är att identifiera mer lämpliga referenstillstånd för olika förvaltningsbehov. Sammanvägt kan detta medföra en bättre förvaltning framöver. Det finns dock utmaningar när det gäller att gå från vetenskap till handling inom förvaltning, så som lagkrav för vilken data och metoder som kan stödja referensvärden eller att sätta realistiska mål. Samtidigt finns det redan befintliga applikationer inom policy i Sverige och internationellt som använder historiska uppgifter. Exempel är tidsserier för landningar från slutet av 1800-talet för hummer och ostron, och val av provtagningsstationer för skyddade områden baserat på längsta möjliga tidsserier, som det stängda området i Kattegatt. Dessa exempel kan tjäna på en närmare utvärdering av vilken påverkan det har haft på målsättningar, förvaltningsåtgärder och faktiska ekosystemeffekter.
Det finns många möjligheter att ytterligare utforska nyttan av historiska data utifrån ett förvaltningsperspektiv i Sverige. Här kan internationella samarbeten
inspirera och verka som en hävstång, i både vetenskaplig förståelse och konkreta tillämpningar i förvaltning, eftersom havsförvaltande myndigheter har kommit olika långt i användandet av historiska källor. Rekommendationer till Havs- och vattenmyndigheten är:
• Välj några konkreta tillämpningar där ett historiskt perspektiv kan vara användbart. Urvalet kan göras baserat på exempel från denna pilotstudie. Bjud in experter att presentera och diskutera tillgängliga historiska källor för de identifierade förvaltningsbehoven.
•Stöd en historisk plattform i form av en webbsida som visualiserar historiska uppgifter för svenska hav. Detta möjliggör en förbättrad kunskap och förståelse om historiska havsmiljöer hos allmänheten, havsmedvetenhet, och det ökar tillgängligheten av historisk information som idag ofta ligger splittrad över flera museer, register, organisationer och enskilda personer.
Summary and recommendations
Coastal ecosystems have gone through considerable transformations since the first human settlements, including loss of large fish, declines of abundant bivalves, marine mammals and birds, areal extent of benthic habitats and more. Over time, what was formerly natural has been lost with previous generations, a shifting baseline that has accelerated over time. In contemporary coastal management, current reference conditions only stretch a few decades at best. Use of recent baselines represents a missed opportunity to restore more of what has been lost and the benefits thereof, including a better understanding of oceans past for improved management for the future. This report presents the outcome of a pilot study with the overarching question ‘How may historical insights on earlier, more natural ecosystem be of use to strengthen ecosystem-based management?’.
Marine historical research aims at reconstructing the past through utilizing interdisciplinary methods and proxies of different kind. This pilot has found th at there is a wealth of records for studying status, causes and consequences related to Swedish coastal seas for the past 10 000 years, the approximate timing for coastal settlements in southern Sweden. These go from scattered bone remains and other archeological findings through historical documents of different character to increasingly meticulous documentation. Some historical records r elated to Swedish coastal seas (e.g. benthic surveys in the late 1800s) may be unique in an international perspective and many offers high quality data (e.g. tax records) and continuous time series for the past 10 000 years (sediment cores). For some records, the window of opportunity for analysis is closing, i.e. ~10 000 years old organic material in the form of bones. However, when utilizing these records for ecological indicator applications, understanding the cultural context is vital, requiring source-criticality and consideration of representativeness of material. This pilot also finds that with further analysis of available records, information on oceans past may inform ecosystem-based management. One opportunity is disentangling natural fluctuations from human pressures and identifying more suitable reference conditions for various policy needs – and thereby better manage for the future. Challenges however exist in translating science to action in current management, such as legal requirements of underpinning data for reference conditions and setting realistic targets. There are however already existing policy applications which utilize marine historical records in Sweden and internationally. Examples include establishment of time series for landings since before modern monitoring (e.g. European lobster, European oyster) and selection of monitoring program stations for closed areas based on longest, possible time series (e.g. the closed area in the Kattegat). These examples may benefit from a closer examination of their efficacy, such as actual management actions and observed ecosystem effects.
Many opportunities exist to further explore the usefulness of historical data with a coastal management focus in Sweden. International collaborations can inspire and provide leverage in both the scientific understanding and tangible management applications. Recommendations to SwAM on how to proceed are:
- Select a few concrete applications where a historical perspective may be useful. This may be guided by this pilot study. Invite experts to present and discuss available historical records for the identified management needs.
- Support a historical platform in the form of a web page that visualizes historical records for Swedish coastal seas for improved ocean literacy on oceans past and improved accessibility to scattered historical information.
In the book The unnatural history of the sea (Roberts 2007), inconceivable pictures are described about how islands, coastal areas and oceans were steaming with life when Europeans first arrived during the colonization period. Countless big fish, oysters, turtles, marine mammals, and birds were described; the marine resources appeared to be endless. Judging from the accounts written at the time by early explorers to these regions, the situation in Europe was at that point in time (1500s-1800s) already far from pristine.
Today, we can perhaps imagine a pre-industrial, terrestrial landscape without highways and shopping malls, with ancient forests and meadows instead – but can the same be visualized for under water marine ecosystems in a more pristine northern Europe? And what point in time is relevant to use for the equivalent reference situations for Swedish coastal areas such as the one depicted by early European explorers?
This report summarizes findings of a pilot study on how historical records of the seas may be of use in a Swedish context, commissioned by the Swedish Agency for Marine and Water Management (SwAM). The overall aim is to investigate if – and how in that case– historical perspectives can contribute to current ocean and coastal management in Sweden. The pilot intends to try to answer three overarching questions:
1. What historical records related to the status of species and habitats in the coastal areas are available for Sweden?
2. How can this information be used in current management?
3. What is needed to implement historical perspectives in Swedish coastal management?
This pilot study also marks a starting point of a collaboration between international researchers and SwAM on historical applications useful for marine management. Thus, to start, strengthening the knowledge capacity of both within SwAM, it´s sister agencies and beyond is sought, to hopefully progress the use of historical records in operational coastal management in Sweden and elsewhere. The focus of this pilot is therefore to introduce available historical sources and research for Swedish coastal seas. These findings are related to how historical records have been used and applied internationally in research and management, bringing in scientific expertise and practitioners’ perspectives. Collectively, this work is intended to provide a first overview as to where marine historical applications are at today in Sweden, and from this, summarize opportunities and barriers for future directions in research and management.
This pilot study is guided by approaches and methodologies used in two overlapping fields of research: marine historical ecology and marine environmental history. The recently published handbook in marine environmental history ‘Perspectives on Oceans Past’ (Máñez & Poulsen 2016) has been used to provide an initial and international overview of the research area. Furthermore, the search for and presentation of available Swedish historical records and research are guided by a couple of the key studies and papers utilizing a marine historical ecology approach that are repeatedly mentioned in the handbook (Lotze et al. 2006; Jackson et al. 2001), and a recent paper summarizing lessons learnt/future outlook for marine historical ecology in a management context (Engelhard et al. 2016).
To answer to the first question of this pilot study, on what information exists on past marine species and habitats in Swedish waters, literature searches (initially guided by the sources described above) were performed in combination with personal communication with scientists from a wide range of disciplines and organizations with historical records. The initial selection of who to contact was much based on project partners’ personal contacts in combination with internet searches and snow-balling techniques (asking contacted persons about others to contact). Available records were categorized into broad temporal periods and data types following the time periods in Jackson and colleagues (2001):
• Archaeological: from ~10 000 years Before Present (BP), onset of coastal settlements.
• Historical: from ~1 000 BP, occurrence of written documents. • Ecological: since late 1800s, onset of scientific data collection.
Sediment cores are available as continuous archives across time periods are presented alongside the timing of archeological records. Older paleoecological records (from 125 000 years ago until present, i.e. rise of Homo sapiens) were excluded since they are considered of less management value. This exercise intended to place available records and perspectives of Swedish marine species and habitats in an international research context and make a first attempt to identify different reference conditions that are of value to current policy ambitions. A separate chapter (Chapter 5) provides perspectives from humanities on the cultural context of the records (archeological remains and written sources). It explores what these records can tell us about the status of Swedish coastal seas, describing some of the caveats in their interpretation.
To address the second question of this pilot, on management value, Swedish and international perspectives were collated to exemplify how marine historical research is currently used or could be used in marine policy and management. This part was guided by the paper by Engelhard and colleagues (2016) in combination with communication with practitioners in marine management at SwAM, but also experiences from the authors. It is not attempting to be an exhaustive list but provides an overview of examples from the USA (west coast), Australia and Sweden (based on the experts involved in the pilot). Furthermore, a scientific illustrator was invited to visualize historical records as a pilot for ocean literacy and public engagement in conservation.
For the third question of this pilot, on what is needed to implement historical perspectives into Swedish coastal management, potential research themes of management value were jointly defined by project partners, marine practitioners at SwAM and experts contacted. These examples offer directions for more fit-for-purpose, dedicated data collection and analysis to follow up upon after this pilot study, in dialogue with experts. Compiling a comprehensive list of available records, as initially attempted by question one, was not seen as feasible within the scope of the pilot study. Furthermore, identifying useful data requires a clear management application.
The scope of interest from SwAM for this pilot study was not specified in time, geography, habitats, species or topics but rather currently available project funds. Therefore, prioritizations had to be done. This was continuously made in dialogue between SwAM and project partners and resulted in an exclusion of records and management needs related to lakes, rivers, streams and the terrestrial part of the coastal zone. Furthermore, the pilot study has a focus on records that can be used as indications of status of coastal seas, and almost exclusively the southern part of Sweden and with much emphasis on fisheries. Indicators on pressures, excluded habitats and areas and human activities beyond fisheries are however seen as important for coastal zone management and are recommended to be further examined in the future.
This pilot study thus aims to provide a general picture. It does not pretend to be a comprehensive review of all available marine historical records and research related to Swedish seas, and merely presents examples. The authors have tried to be inclusive but want to express sincere apologies to anyone experiencing oversights.
Since the aim is to commence collaborations and identify potential applications along the way, the authors encourage everyone with useful records related to past Swedish seas to get in contact for continued work.
Marine Environmental History and
Marine Historical Ecology
The research areas of environmental history and historical ecology are relatively new (1960s) and describe research utilizing a wide range of scientific methods and historical sources to investigate the nature of interactions between humans and nature over time, and the outcomes of these interactions for natural ecosystems and our societies. Environmental history is rooted in forestry, with different strands having developed over time (Szabó 2015), while historical ecology is rooted in understanding human impacts and management histories on terrestrial landscapes (Crumley 2017). Both marine historical ecology and marine environmental history has gained more recent interest (1990s) compared to their terrestrial counterparts. The two fields overlap but may have slightly different research emphasis (Box 1).
Box 1 Definitions
Marine historical ecology is defined as ‘the study of interactions
between human society and the seas and oceans’ (Engelhard et al. 2016). Research involves utilizing historical records to establish longer historical baselines for species abundance and habitat distribution – with implications for ecosystem function – before the onset of intensive exploitation.
Marine environmental history analyses ‘the changing
relationships between human societies and marine natural resources over time’ (Máñez and Poulsen 2016). Research involves longer historical baselines, such as fisheries landings, but may have more emphasis on the impact on and response of society from historical interactions with nature.
Today, there is a growing interest and value of utilizing historical materials for scientific investigation of long-term environmental changes, including marine systems (Kwok 2017). Emerging in the early 2000s as a distinct area of research, marine historical ecology is now considered by many to be a discipline within marine sciences (Engelhard et al. 2016). The field has developed through collaborative efforts between fisheries scientists, ecologists, historians, archaeologists, sociologists and economists. The multidisciplinary approach related to marine historical research has not been without challenges since it requires a critical dialogue across sciences (Keiner 2013).
The handbook of marine environmental history edited by Máñez and Poulsen (2016) offers a convenient introduction to international research related to marine history. This book highlights some classic papers, with three key lessons learnt. Pauly (1995) introduced the ‘shifting baselines syndrome’ in fisheries, i.e. a phenomenon which occurs
over time when a resource is being depleted and gradual shifts occur in peoples mind and management related to what is seen as “natural” ecosystems. Consequently, only utilizing recent observations underpins myopic goals for restoration of coastal ecosystems – lesson number one on why longer historical baselines are vital for coastal marine management. Another seminal paper by Jackson and colleagues (2001) utilized a combination of retrospective data from several different research areas as proxies (biological, biogeochemical, physical and historical)1, beginning from the onset of human
settlement u ntil today. The aim was to improve our understanding of when, why and how changes occurred and thereby avoid short-sightedness. It was found that ecological extinction of species from overfishing has been the historically main driver behind coastal degradation globally. Lesson number two is that a combination of records and disciplines are important to understand changes in the coastal zone. The finding that fishing is an important driver of change is also supported by Lotze and colleagues (2006), who utilized the same historical time frame and included multiple stressors of the coastal zones. They analyzed patterns in the ecosystems during different cultural periods (e.g. hunter-gatherer, establishment of markets). All coastal systems displayed the same message: long period of slow decline followed by rapid acceleration of coastal degradation. The timing of events varied around the world. Lesson number three is thus that every region has its own set of baselines; which one in need to be re-constructed through historical records depends on management questions.
Biological = e.g. fossils or archaeological remains; Biogeochemical = e.g. isotopes and parameters such as temperature and oxygen; Physical = e.g. sedimentary structures and composition; Historical = e.g. commercial records, naturalist descriptions
Since many historical records are less accessible, considerable effort in the field is often undertaken to digitize different historical sources to enable analysis, seen for all international, collaborative initiatives (Table 1). The Oceans Past Initiative (OPI) is today the main global umbrella for marine historical research, entirely funded by its members, sharing information and datasets from different old and ongoing initiatives around the world at their website.
To this end, numerous initiatives and case studies around the world have now illustrated the value of marine history for improving our understanding of the dynamics of marine social-ecological systems – it is undoubtfully important to learn from the past to better understand current and potentially future seas (e.g. Yasuhara et al. 2020). Given the intensification of pressures over time (e.g. Lotze et al. 2006), it is increasingly important to not repeat the same mistakes. Unfortunately, new agendas such as Blue Economy fail to acknowledge factors that contributed to unsustainable use in the past (Caswell et al. 2019). This further motivates historical perspectives into contemporary and future management.
Table 1 International initiatives on marine history. All have datasets related to Swedish costal seas.
Name and website Description
Ocean Past Initiative (OPI)
Global research network for marine historical research. Aims to “enhance knowledge and understanding of how the diversity, distribution and abundance of marine life in the world’s oceans has changed over the long term to better indicate future changes and possibilities”.
History of Marine Animal Populations (HMAP)
The historical component of the Census of Marine Life. The data generated, ranging from 1600s, is now available at OPI website. Project is finalized.
Compilation of global fisheries catch data since 1950s. Has also a dedicated page listing historic expeditions (1598-) and recent surveys, with descriptive information on what was collected.
https://www.ices.dk/ community/groups/P ages/WGHIST.aspx
The Working Group on the History of Fish and Fisheries (WGHIST) explores and communicates the value of historical perspectives, e.g. improve accessibility of historical meta-data and promoting best practice.
Swedish records on oceans past
This chapter provides a brief introduction to examples on the kind of records that are available for building proxies of social-ecological change at different time scales for Swedish coastal areas and what may be interpreted from them. It does not intend to present a complete picture of the past. Different historical perspectives on Swedish coastal seas have before been presented in several Swedish reports (with English summaries), such as fisheries (Ask & Svedäng 2019; Hentati-Sundberg 2017) and broader coastal development (Havsmiljöinstitutet 2015). Through these reports, in combination with literature searches done during this pilot, it can safely be said that a considerable amount of historical research and records are available for Swedish coastal seas. A full account was therefore not feasible within the scope of the pilot study, but examples are provided below for different time scales.
The approximate timing for the commencement of coastal settlements in southern Sweden, ~10 000 years Before Present (BP) (e.g. Schmitt et al. 2009), the Swedish coastline likely resembled an Antarctic coast with nutrient rich melt water run-off from the last glacial period, and high primary production attracting filter feeders such as large whales (Anderung et al. 2009). Several opportunities exist for multiproxy investigations of interactions between humans and nature since then, but the only continuous record available in this time scale are sediment cores from the bottom of the sea (Figure 1). These represents archives of oceans past and are in general of very good quality in Swedish coastal waters due to high occurrence of mud and de-oxygenated sediments that offers excellent conditions for extracting accurate dating chronologies and high rates of preservation of material2. Therefore, through sediment cores, opportunities for utilizing
physical proxies to investigate long-term changes in e.g. eutrophication pressure as well as biogeochemical proxies such as stable isotope analysis or DNA, or parameters such as temperature, oxygen and salinity from sediment cores are plenty.
2 Elinor Andrén, paleoecologist, Södertörn University, Personal Communication October 26th
Figure 1 The illustration integrates different studies to provide a rough overview on material available and challenges in interpretation. Studies include oceanography through sediment cores (Nordberg 1991; Bianchi et al. 2000), bone finds and coastal settlements (Boethius et al. 2020; Schmitt et al. 2006), archaeological finds on population growth and diets (Lewis et al. 2020), detection of human impact on the Baltic (Lotze et al. 2006) and general availability of written historical and scientific records identified in this report. It is shown that from the initial coastal settlements in southern Sweden (~ 10 000 years BP), human societies and coastal ecosystems have gone through major changes (depicted below the time scale), both from natural causes (changes in e.g. temperature, circulation, salinity) and human-induced (predominant mode of living by the sea). The area shaded in grey illustrate current baseline for documented human influence. Available records offer different challenges and opportunities to detect trends, such as continuity (sediment cores), patchiness (bone records), short-sightedness (scientific data collection), varying quality (written records). Illustration: Maria Eggertsen.
Organic material available date back to ~10 000 years BP, such as b ones excavated from places with optimum storage circumstances but are more scattered in their occurrence and quality over time (Figure 1). These records also offer unique opportunities for research with biogeochemical proxies, described in an overview provided by Boethius and colleagues (2020). Through applying biogeochemical proxies, studies on migration patterns of marine fauna and humans, historical food webs, size- and species composition are possible3. For some material, DNA applications are possible due to well
preserved DNA. One example, the project Catching the Past4 use so called ancient DNA
from 9 000-year old Atlantic cod Gadus morhua fish bones to reconstruct long-term patterns of cod diversity. From this, potential demographic and selective changes during history of exploitation may be revealed. However, one challenge is site locations (often at bottom of sea). This cause challenges for estimates of demography and population densities.
3Adam Boethius, archaeologist, Lund University, Personal Communication September 15th 2020
4https://www.mn.uio.no/cees/english/research/projects/144484/ (Accessed on October 6th
There are also vast amounts of biological proxies available in the form of bone material that have been excavated during commissioned projects in association to e.g. road constructions. This material offers scattered records for further analysis, increasing in abundance and quality in more recent times. The material located so far is described in reports, but due to limitations in scope and time, seldom analyzed and published scientifically. Records of available b one fragments are found in the GIS-database Intrasis5, and reference bone collections are stored at museums. However, since fish
bones are fragile, representative samples require more dedicated collection techniques. Commissioned projects are additionally often short of time; combined, this does not always allow for a representative picture of the fish fauna. One major challenge is also getting an overview of what bone material is available. A Nordic collaboration called Oceans Past Northern Seas Synthesis, initiated b y Dr James Barrett at University of Cambridge, is therefore c reating a data base o n available fish bone excavations around the Baltic, North, Irish, Celtic, Norwegian and Barents Seas over the last 2 000 years. Pilot research under the European COST project Oceans Past collected information on approximately 1 000 assemblages including one million identified fish bones6.
5 https://www.intrasis.com/ (Accessed on 23rd of September 2020)
https://www.arch.cam.ac.uk/research/projects/current-projects/oceans-past-northern-seas-synthesis (Accessed on October 6th 2020)
The current collections at museums also offers bone material of use for biogeochemical proxies to investigate changes in Swedish coastal seas in more recent times. As an example, one study investigated the bones of the once abundant but since mid-1800s extinct Great Auk Pinguinus impennis (Thomas et al. 2019). Through use of DNA techniques, involving bones found at Swedish museums, researchers established the relative pressure of hunting and climate. They concluded that hunting was the main reason behind the Great Auk’s extinction, providing important lessons on that even an abundant and widespread species can be vulnerable to intense and localized exploitation. Evaluating the status of Swedish coastal seas from occurrence of fish bones are however more complicated in more recent times due to considerable trade of fish established
already during the Viking era7. After the so-called Fish Event Horizon (around 1 000
years BP) a marked shift from freshwater fish to marine are found in archaeological deposits in the UK, and marine fish became increasingly traded in Europe (Barrett et al. 2004; Barrett et al. 2009). This requires strategies to identify if bones are locally caught or brought in by trade (Maltin and Jonsson 2018). This can be done t hrough morphological studies by fish bone experts (Jonsson 1986) but also through rapidly developing applications of modern technologies such as e.g. isotopes (Orton et al. 2011) and DNA (Star et al. 2017).
7 Emma Maltin, PhD candidate in archaeology, Stockholm University, Personal Communication
September 15th 2020
Vast amounts of subfossils are also available – the world’s largest natural-made shell bank is found in Bohuslän on the Swedish west coast8. These remains are from the end
of the last glacial period (~11 000 years BP) and includes, besides shells, other invertebrates, fish and several species of marine mammals. There are also post-glacial shell collections at raised beach sites including oyster beds at many places on the Swedish west coast (e.g. Otterön and Koster).
8 https://www.bohuslansmuseum.se/besok-museet/skalbanksmuseet/ (Accessed on October 6th
The Swedish west coast, a 10 000 years perspective
In the material found, there are indications of high human populations densities in some coastal areas such as Huseby Klev on the Swedish west coast ~10 000 years ago (Schmitt et al. 2006). In this material (bones and shells), there are indicative changes in local marine species populations seen, such as shifts from marine mammals to fish. Records also tells stories of different ecosystems, with bones from the now extinct great auk dominating at times (Nordqvist 2005; Figure 2). The drivers for this potential shift have not been established, but to which extent this affects baselines for pristine seas would merit from further investigation.
It is also important to acknowledge that significant natural changes have occurred in the ecosystem during the past 10 000 years – a time period that include dramatic global climatic shifts such as the Holocene Thermal Maximum and regional changes such as the isostatic land uplift with great impact on e.g. the Swedish west coast and surrounding seas (Figure 1). This information is available from sediment cores, where the Swedish west coast has been extensively investigated. From this research, it has as an example been found that the current sea circulation system was established ~4 000 years BP (Nordberg 1991). Sudden changes in sediment structure and species composition has also been identified at around 5 500 years BP (Conradsen & Heier-Nielsen 1995). There is also an indication that since ~1 700 years BP the increased Baltic Outflow and precipitation caused higher primary productivity in the coastal waters (Polovodova Asteman et al. 2018a). In particular, fjord sediment archives from the Swedish west coast have been studied regarding more recent environmental changes. For instance, the Gullmar fjord archives showed clear benthic responses to changing temperatures and hypoxia over past millennia (e.g. Polovodova et al. 2011; Harland et al. 2013; Polovodova Asteman & Nordberg 2013; Polovodova Asteman et al. 2013, 2018b), while sediment cores from Sannäs Fjord and Kosterfjord demonstrated ecosystem changes over the latest decades due to shallow water hypoxia and increased land runoff (Polovodova Asteman et al. in press; Polodova Asteman et al. 2018; Asteman et al. 2018; Nordberg et
al. 2017; Harland et al. 2013; Polodova Asteman et al. 2013; Asteman & Nordberg 2013; Polodova et al. 2011;). Some of the cores have been stored and could be further analyzed for other applications9.
9 Irina Polovodova Asteman, geologist and micropaleontologist, University of Gothenburg,
Personal Communication on October 8th 2020
Figure 2 Other species and abundances characterized the Swedish west coast when early settlers arrived, the Hensbacka culture ~10 300–9 300 yeas BP (Schmitt et al. 2009). The illustration is informed by historical accounts on abundance before intensive exploitation (Roberts 2007) and archaeological bone finds (Nordqvist 2005; Enghoff et al. 2007; Hufthammer et al. 2018; Thomas et al. 2019). Illustration: Maria Eggertsen.
The Baltic Sea, a 10 000 years perspective
The Baltic Sea has gone through many changes related to glaciation and post-glacial rebound during the past 10 000 years, developing from a freshwater lake to the current brackish ecosystem (Littorina sea, ~7 500 years BP).
In terms of material from archaeological excavations, mass consumption of fish is seen already during early Holocene (9 600-8 600 years BP) in southern Sweden, corresponding to Mesolithic in human development in Scandinavia (Boethius et al. 2020). Stable isotope values in human bone material indicate that aquatic resources dominated protein intake, and techniques for large fish storages (fermentation) and fish traps designed to capture large amounts of fish have been found. A recent multiproxy analysis for southern Scandinavia has in fact demonstrated that population increase in southern Scandinavia was driven by periodically high marine productivity due to
favorable climatic conditions (Lewis et al. 2020). The authors suggest that the first period (7 600-7 100 years BP) drove development and innovation, whereas the second period (6 400-5 900 years BP) enabled a four-fold human population growth. Furthermore, the predominant mode of subsistence changed from marine to terrestrial around 6 000 years BP (Figure 1). This period is thus suggested to indicate the beginning of marine ecosystems in southern Sweden being increasingly impacted by humans. Another earlier study by Warden and colleagues (2017) also found a sudden change towards agriculture around 6 000 years BP. They suggest increased hypoxic conditions in the Baltic sea due to rise in temperature in combination with favorable conditions for farming drove the change from marine to terrestrial subsistence. Furthermore, more recent fish bone remains indicate that a variety of fishing methods have been used since the 5th century in
the Baltic (Enghoff 1999).
Sediment cores from the Baltic have also been extensively studied (e.g. Jonsson et al. 1990; Jonsson & Carman 1994; Kabel et al. 2012; Norbäck Ivarsson et al. 2019; Andrén et al. 1999; Andrén et al. 2020). In fact, Jackson et al. (2001) points out that some of the oldest and longest records from sediment cores are from the Baltic Sea. Cores have indicated that the onset of significant coastal changes differ greatly between areas, but longer reference situations are required to understand pristine conditions than is currently utilized10. One example contributes with an 8 000-year perspective of algae
blooms, showing that massive summer blooms of cyanobacteria are as old as the present brackish-water phase of the Baltic Sea, i.e. a reoccurring natural phenomenon before man-induced pressures such as eutrophication (Bianchi et al. 2000). Another study has shown that hypoxia has occurred intermittently in deeper areas during most of Holocene, starting ~8 500 years BP when the permanent halocline of the brackish water stage was established (Zillén et al. 2008). The same study detected human signals influencing increased hypoxia already during the Medieval warm period.
10Elinor Andrén, paleoecologist, Södertörn University, Personal Communication October 26th
There are also many paleoecological studies, most with focus on changes in sea level and salinity, but many studies have also looked at trends in nutrients and productivity (Weckström et al. 2017). Many observed changes in trophic state and productivity have been linked to climate through freshwater discharge and marine water inflow.
Swedish records for utilizing quantitative historical proxies may be unique in an international context, especially for the west coast11. Examples include demographic data
on births, marriages, and deaths in Sweden between 1620 to 185012 and quantitative data
is available on agricultural production in Sweden with high resolution from 1630 (Andersson Palm and Linde 2012; Hallberg et al. 2016). Data on tourism was collected already in the 1800s. Records of sea ice cover extend back to 1720 for the Baltic sea13.
11Poul Holm, Professor of Environmental History at Trinity College Dublin, guest professor at
University of Gothenburg and chair of the Steering Committee of Oceans Past Initiative, Personal Communication on September 16th 2020
12Erik Hallberg and Daniel Larsson, historians at University of Gothenburg, Personal
Communication October 27th 2020
Statistics on fisheries were also collected early on. These records allow for studies on Swedish fisheries from 1859 and onwards; for herring fisheries and processing back to 1550s.
There is also a considerable amount of historical sport fishing data available of various quality14. These include, amongst others, surveys (1970s-) that need to be calibrated for
more robust time series (data collection methods and gear types usually change over time), journal records from closed sport fishing clubs with high level of detail (1960s-), an annual catalogue ‘Napp och nytt’ with a lot of photographs, sport fishing competition records, sport fishing magazines listing top ten largest individuals caught each year for selected species, etc. One source of information is seen as unique, the Big Fish register (‘Storfiskeregistret’). This holds over 37 000 entries of fish caught over a certain size (e.g. Atlantic cod 17 kg, pike 12 kg, perch 1.6 kg) since 1973 in different Swedish coastal areas and lakes. In 1973, cod was estimated to contribute with 50% of the recreational fish catches from the west coast (SOU 1978:75). In the Big Fish register, data from the 1970s are not fully representative due to low number of reports at start. However, since the 1980s, trends are seen both in terms of the share of cod in the Big Fish annual register (declining from 6.6% down to 0.3% in recent years) and number of individuals exceeding 17 kg (from 282 to only two during 2015-2019; Figure 3).
14Markus Lundgren, Swedish Anglers Association, and Stig Thörnqvist, retired from SwAM,
Personal Communication October 14th 2020
0 50 100 150 200 250 300 0 2000 4000 6000 8000 10000 12000 14000 16000 1980s 1990s 2000s 2010s C o d ≥ 17 kg Re p o rt s
Total reports Cod reports
Figure 3 Reports of cod ≥17 kg in the Big Fish register and total number of reports. Data provided by Stig Thörnqvist.
There are also other kinds of historical records of different origin related to uses of the seas. Historical studies of fishers, including interviews, have been performed at different points in time (e.g. Hasslöf 1949; Björkvik et al. 2020). Furthermore, in travel writings by Carl von Linné (1707-1778) he tells stories of eelgrass being used as roofing, insulation and mattresses, and macroalgae used for fodder and fertilizer15; these records are
replaced with other materials today. There are also opportunities to analyze fish
15Lena Kautsky, researcher in marine ecology at Stockholm University, Personal Communication
consumption and fisheries through e.g. trade data, but also scattered information found in e.g. news archives, journals, and more, offering snap shots of information on past fisheries16. This material requires considerable effort to collate and analyze, so the
intended application needs to be clearly defined first. Recent initiatives on initiating digitalization are very valuable. These include a searchable website for items found at museums in Sweden and Norway (currently listing over 3.1 million objects)17 and
Swedish newspapers since the 1730s18. There have also been initiatives to create
bibliographies concerning Swedish fisheries19. An extremely helpful collative effort for
international researchers is the bi-lingual summary on historical records provided by Armin Lindquist on 500 years of fisheries in Swedish waters20. Easier access to available
records allows for many different marine historical ecology applications, such as the potential use of old photographs (McClenachan 2009) and popular media (Thurstan et al. 2016a). Challenges however exist in converting qualitative information to quantitative.
16Jonas Hentati-Sundberg, Swedish University of Agricultural Sciences, Personal Communication
October 8th 2020
17https://digitaltmuseum.se/ (Accessed on November 25th 2020)
18https://tidningar.kb.se/ (Accessed on November 25th 2020)
19https://www.ksla.se/anh/files/2012/03/Havsfiskebibliografi.pdf (Accessed on November 26th
https://www.slu.se/globalassets/ew/org/inst/aqua/externwebb/publikationer/ovriga-publikationer/500-ars-fiske.pdf (Accessed on November 26th 2020)
Biogeochemical proxies include records on wind, salinity, currents, water- and air temperature from lightships (two times per day, different depths during May to November 1880-1970s)21 and air temperature from the Stockholm Historical Weather
21 http://smhi.diva-portal.org/smash/record.jsf?pid=diva2%3A947588&dswid=page (Accessed
on October 6th 2020)
https://bolin.su.se/data/stockholm-thematic/homogenized_monthly_mean_temperatures.php (Accessed on November 23rd 2020)
The Swedish west coast, a 1 000 years perspective
The Bohuslän herring periods commenced around 1 000 years ago, each lasting for a few decades and being separated by 50–70 years (MacKenzie et al. 2002). Most herring fishing were performed from shore, using beach seines, and due to the major importance to coastal communities there are plenty of historical records associated to these fisheries. There are several historical records of quantitative character related to the Swedish west coast from the past centuries. Catch statistics for harbour porpoise are available from 1715 (Kinze 2000). Late 1800s collection of data on Swedish commercial fisheries (fisheries data, survey data) have also been standardized in terms of catch per unit effort and extensively studied during the project Waking the Deads for the Kattegat-Skagerrak area: European lobster Homarus gammarus from 1875 (Sundelöf et al. 2013), Atlantic cod Gadus morhua from 1906 (Bartolino et al. 2012), turbot Psetta maxima from 1925 (Cardinale et al. 2009), Atlantic haddock Melanogramus aeglefinus and pollack Pollachius pollachius (Cardinale et al. 2012), European plaice Pleuronectes platessa from 1901 (Cardinale et al. 2011, 2010), and skates Dipturus spp., Atlantic cod, ling Molva molva, Atlantic halibut Hippoglossus hippoglossus, Atlantic haddock, whiting Merlangus merlangus and tusk Brosme brosme from longline fisheries during 1859-1960 (Cardinale et al. 2015). All studies illustrate major declines in abundance. Studies
have often combined scientific collection with historical proxies. References to the wide range of available material is found in Ask & Svedäng (2019), Ask and colleagues (2015) and Hentati-Sundberg (2017).
The benthic surveys by Petersen in this same area also offers unique material on habitat status before onset of trawling and is considered to be the earliest most comprehensive benthic assessment in the world – the first qualitative assessment was performed already in the 1880s (Josefson et al. 2018; Petersen 1893, 1913, 1915).
The Baltic Sea, a 1 000 years perspective
It has been suggested that there has been demand for fish resources from the North Atlantic for Baltic Sea countries since the Viking era, due to presence of imported fish (Star et al. 2017). Lotze and colleagues (2006) also identified in their multi-proxy analysis severe resource depletion by Medieval times (1 000 years BP) for the western Baltic Sea. Through study of sediment cores, human influence on the Baltic hypoxia has also been detected already during the Middle Ages, considered due to the onset of extensive deforestation and intensified agriculture (Zillén et al. 2008). Combined, these records indicate that there is need for at least a 1 000 years perspective for more natural reference conditions.
Historical records related to Baltic Sea fisheries have also been intensively investigated. As an example, MacKenzie and colleagues (2007; 2011) utilized records on cod fisheries from the mid-1500s. They found that the Baltic ecosystem historically supported comparatively large cod abundance, despite lower productivity and large populations of predators such as seals. Several studies have also utilized historical records to determine historical seal abundance, such as culling (e.g. Hårding & Härkönen 1999).
Although human influence on the Baltic sea has been detected already 1 000 years ago, they have however been most clearly found in the past 100-150 years, with the rapid acceleration of pressures associated with industrialization (Weckström et al. 2017). Signs of recovery have recently been seen, but the Baltic Sea is still far from its pre-industrial state, as it is affected by pro-longed overfishing, eutrophication and pollution.
Ecological records, i.e. scientific literature, may be used to calibrate older historical records, enabling understanding of changes over relatively recent periods of more intensive exploitation (Jackson et al. 2001). Swedish ecological records offer some unique data sets in an international perspective. One of the world’s oldest marine biological research station is in fact situated on the Swedish west coast, Kristinebergs zoologiska hafsstation, founded in 1876. Systematic, more scientific collection of fisheries data commenced after the 1850s in Sweden in the form of scientific surveys. For the Baltic Sea, continuous datasets for several organism groups (plankton, benthos, fish) are available since the mid-1950s (Ojaveer et al. 2010).
There is today a wide range of environmental monitoring programs that regularly assesses the status of Swedish coastal seas23. Harmonization has been called for24, and 23 Maria Jansson, SwAM, Personal Communication October 7th 2020
24 Sveriges miljöövervakning – dess uppgift och organisation för en god förvaltning. Betänkandet
is ongoing. National databases for Swedish coastal waters include Sharkweb at the Swedish Meteorological and Hydrological Institute (SMHI), fish monitoring data performed by the Swedish University of Agricultural Sciences (SLU), commercial landings at SwAM, fisheries and aquaculture production at Statistics Sweden, a wide range of environmental monitoring programs and more. Trends are available for harbour porpoise, phytoplankton, seals, benthic fauna, the water column, fish and nutrients at a recent initiative, Sveriges vattenmiljö – but with the perspectives of recent decades25.
25https://www.sverigesvattenmiljo.se/karta#5/62.196/17.007/all/all/all/none (In Swedish,
Accessed on November 23rd 2020)
There are also international data bases with records related to Swedish coastal seas, including the International Council for Exploration of the Seas (ICES) (e.g. commercial fisheries landings, benthic pressure indicators, discard sampling, survey trawling) and Scientific, Technical and Economic Committee for Fisheries (STECF) that disseminate data collected under the EU Data Collection Framework related to fisheries and aquaculture.
For many ecosystem components, however, continuous datasets are lacking or offers very short time perspectives (decades). There may be scientific data collection offering snapshots that may be followed up. As an example, for macroalgae in the Baltic sea, Mats Wærn pioneered surveys of these communities using dive transects in 1943-194426.
When sites were revisited 40 years later, Fucus vesiculosus had decreased in depth distribution by on average 3 meters at all sites (Kautsky et al. 1992). Follow up monitoring at the same sites today show clear recovery in depth distribution26. There is
a wealth of other scientific publications that have included sampling of certain areas, species or communities that are often not covered by regular monitoring or have data from before regular monitoring commenced (see examples in Table 2). Challenges with this information is patchiness of data, both in time and space. There is also plenty of research taking a broad perspective on human influence on the Baltic sea through multiple pathways (e.g. Elmgren 1989, 2001; Österblom et al. 2007)
26 Sofia Wikström and Lena Kautsky, Stockholm University, Personal Communication November
Much work on reference conditions has also already been done related to establish trends for the Marine Strategy Framework Directive (MSFD)27. The existing reference
conditions for ecosystem components in the MSFD are however very recent or even missing, e.g. for marine birds 1990-2000, phytoplankton time series commence (at earliest) in 1983 depending on sea basin and there are no reference conditions for pelagic habitats. The Swedish Species Initiative also assesses every five year all species for the national IUCN Red List of Threatened Species28. In these assessments there is much
expert knowledge and collected data that may be useful for longer reference conditions. Cross-checking what has been found and used in these efforts with more dedicated literature searches and contacts with experts may be a useful step towards elongating baselines for different species and habitats.
https://www.havochvatten.se/planering-forvaltning-och-samverkan/havsmiljoforvaltning/inledande-bedomningen-i-havsmiljoforvaltningen.html (Accessed on December 14th 2020)
Table 2 Examples of scientific studies that offers inventories of use for historical reference conditions in more recent times. Some compare recent records with older data. Note that this is not intending to be a comprehensive list.
Study object Oldest record
macroalgae 1890 Kolderup Rosenvinge 1909; Rosenvinge & Lund 1947; Pihl et al. 1999; Karlsson 2001; Eriksson et al. 2002; Havsmiljöinstitutet 2015
fish community 1893 Petersen 1893: Pihl et al. 1994; Pihl & Wennhage 2002
coast eelgrass Zosteramarina 1893 Petersen 1893; Baden et al. 2012; Moksnes et al. 2018 oysters 1893 Petersen 1893; Thorngren et al. 2019 benthic
invertebrates 1893 Petersen 1893, 1913, 1915; Molander 1928; Gislén 1929, 1930; Jägerskiöld 1971; Rosenberg et al. 1987; Josefson et al. 2018; Obst et al. 2018
marine birds 1947 Åhlund 1980, 1996; Skov & Durinck 2000; Flodin & Grahn 2003
phytoplankton 1903 Hällfors et al. 2013
marine birds 1940s29 Andersson 2000; Greenwood 2007
macroalgae 1943 Waern 1952; Wallentinius 1976;
Wallentinius 1979; Kautsky et al. 1992; Eriksson et al. 1998
sea zooplankton 1960 Gorokhova et al. 2016
fish community 1971 Ljunggren et al. 2010; Olsson et al. 2012; Bergström et al. 2016
invertebrates 1993 Boström & Bonsdorff 1997 eelgrass Zostera
marina 1993 Boström & Bonsdorff 1997
West coast and
ice coverage 1720 Havsmiljöinstitutet 2015 water column
1877 Havsmiljöinstitutet 2015
29 Estimate based on Ottenby Bird Observatory activities, but there are older records available
https://www.ottenby.se/forskning/publikationer/?term=&author=&ar=1947 (Accessed on
Study object Oldest record
sea phytoplankton 1883 Havsmiljöinstitutet 2015; Henriksen 2009 eelgrass Zostera
marina 1890 Boström et al. 2014 harbour
1950s Berggren & Arrhenius 1995
Summary and outlook
Fishing has been practiced for the past 10 000 years and onwards in the Swedish coastal areas. Signals of human effect on coastal ecosystems stretch back for at least 1 000 years. This advocates for use of considerably longer time series than what is applied in contemporary management.
The different records available from the first southern Sweden coastal settlements and onwards allow for further investigations at different time scales and continuity (Figure 1). There is a repeated notion that several sources of high-quality (some unique) materials exist for Swedish coastal seas that are able to shed light on past environmental status. Well-preserved organic material, sediment cores from the bottom of the sea and exceptionally long time series on historical records offer opportunities to analyze interactions between humans and Swedish coastal seas from pristine to current status. Much of this material has been investigated scientifically already, and plenty of comparisons exist when newer and older records are being compared (see examples in Table 2), but this material can be further analyzed. One example is determining the onset of detectable human pressure on coastal seas. Perhaps a meta-analysis would be a useful next step to determine the relative role of human pressure and climate for Swedish coastal seas over the past millennia.
There is also great interest from researchers to operationalize their historical research for management applications. This however calls for specific management questions to determine feasibility and potential management value. Available records may require considerable effort to collate and analyze, calling for dedicated effort with clear purpose. Examples include the wealth of historical records and utilizing available bones to determine variations in species composition, age- and size composition, feeding habits etc. by osteologists and/or through use of biogeochemical proxies (stable isotopes and DNA). Boethius and colleagues (2020) however find that the window of opportunities for e.g. DNA applications is closing due to accelerated deterioration of organic archaeological remains. Sediment cores are useful to illustrate long time series, and modern technologies such as DNA applications offer endless opportunities (e.g. Armbrecht et al. 2019; Li et al. 2019); increased utilization of sediment cores could prove to be a cost-efficient environmental monitoring (NOAA 2020).
There are thus ample opportunities for further investigations. Cederqvist and colleagues (2019) conclude that environmental history seems to have been thoroughly investigated
for terrestrial resources in Sweden (forests, agriculture, minerals and energy) but less so for the marine environment, such as Baltic Sea governance. The same perspective has been given from discussions with historians during this pilot; there is a wealth of historical material available that can be used for analyzing status and pressures on Swedish coastal seas, but the attention has so far been on the terrestrial side30. This
indicates that there may still be ample opportunities for more multiproxy analysis, i.e. interdisciplinary investigations of interactions between humans and nature over time.
30 Meeting on October 5th 2020 with researchers at University of Gothenburg (Christian Isendahl,
Erik Hallberg, Daniel Larsson, Bettina Schulz Paulsson) and Poul Holm (Trinity College Dublin and University of Gothenburg)
In an international perspective, much of the earlier marine historical ecology research effort has only extended the time horizon back to the mid-1800s, reflected in e.g. the case studies showcased in Engelhard and colleagues (2016). Longer time series are less common but do exist (e.g. Holm et al. 2019, 2016; Eddy et al. 2010) but may perhaps be of less use to present day policy. However, opportunities to extend further back may also be limited in available records internationally but may be possible for Swedish waters. This would be of high value from an international research perspective; it could also bring new perspectives into marine management not conceivable before.
What may be interpreted from
Swedish historical records?
This chapter provides a humanities perspective on historical records in the form of archeological remains and documents available that relate to Swedish coastal seas. What may these records tell us about the status of Swedish coastal seas – and what provide caveats in their interpretation?
Finds to cultural ecology: disentangling
geography, climate and society
Both historical and archaeological material are fragmented sources. Even if and when enough material is available for quantification, there are a number of contexts that have to be analyzed for the material (ecofacts, artefacts, texts31) to become useful in an
analytical process. Source material always undergoes what archaeologists call “site formation processes”; things we uncover today have been shaped by a particular natural and cultural environment. Below is a short summary of such contexts.
31 Ecofacts being natural remains (plants, seeds, bones, etc.), artefacts being man-made objects
and written texts being used interdisciplinary to complement and contrast archaeological interpretations.
The dynamic geography of a post-glacial seascape. The Baltic Sea has undergone
enormous transitions during the ~12 000 years of glacial retreat and crustal rebound, through various stages of freshwater lake and inland sea. This dynamic has not only reshaped the ecological prerequisites but also structured societal expansion, settlement patterns and subsistence. Novel environmental conditions can pose both challenges and opportunities. There are clear signs that the “man the hunter” paradigm, prevailing in the conceptualization of the Mesolithic, must be re-evaluated (e.g. Boethius et al 2020) as it is becoming increasingly evident that the exploitation of coastal seafood resources seem to be a major factor in the spread of stone age cultures: from the first pioneering settlers colonizing previously glaciated zones, to the so called bell beaker culture of the Neolithic, which seems to have formed a maritime coastal cultural identity side-by-side with the agrarian battle axe culture (Eriksson 2004)
Cultural adaptation to environment and ecology. Depending on technological
know-how in connection to ecological prerequisites, different niches of the landscape and seascape were colonized and utilized under different epochs. It is evident from research that until the beginning of the medieval period, societies utilizing aquatic resources had concentrated their efforts to collecting oysters, fishing inland and in shallow coastal waters, complemented by seal hunting, bird catching and egg collecting. A very decisive eco-cultural entanglement can be seen in the various cultures hunting seals that seem to have been created in different regions during periods of the Neolithic, bronze age and iron age/medieval periods. These cultures seem to have created iconography, ornaments and rituals centered around honoring of seals (e.g. Österholm