What is the ocean: A sea‐change in our perceptions and values?

1. Throughout human history, the ocean has occupied myriad cultural meanings, mythologies and practices, which were often founded on a notion of the sea as being so large and ‘powerful’ as to be immune to human impacts. These conceptions were grounded in observations from the surface or shoreline, and in periods when human activities in the ocean were more technologically and spatially limited than they are today.
2. Advancements in science and technology have significantly altered how humans interact with and access the ocean, allowing exploration and exploitation of ocean areas and processes that were previously incomprehensible. This new capacity to understand and extract from the ocean might be expected to profoundly alter human relationships to it and conceptions of it.
3. As public support and engagement with marine conservation and ‘blue economies’ stem from value and belief systems, future marine management will benefit from recognizing our historical marine relationships as context for changes in understanding, use, and the increasing environmental degradation faced by the ocean. This review focuses on perspectives of the ocean that have been held historically and queries their future persistence at this potential turning point in our relationship with the ocean.

     

The status of the freshwater pearl mussel Margaritifera margaritifera Linn. in Scotland

1. One hundred and sixty rivers in Scotland with historical records of freshwater pearl mussel Margaritifera margaritifera were surveyed between 1996 and 1999 for the presence of the species. 2. M. margaritifera populations were classed as either ‘extinct’ (no mussels remaining), ‘not currently viable’ (ranging from only dead shells present to no juveniles present, regardless of the number of adults found), or ‘functional’ (at least one juvenile was found, regardless of the overall numbers of adults present). 3. M. margaritifera populations could be classed as ‘functional’ in only 52 rivers (34% of total surveyed) and in only 17 of these were juveniles below 20 mm (5 yrs old) present. Furthermore, in only 10 of these functional rivers were mussels also still considered either to be common or abundant and these included both large easterly‐flowing rivers and small western rivers and streams. 4. In approximately two‐thirds (101) of the 155 rivers occupied 100 years ago, M. margaritifera is now extinct or is about to become extinct. Furthermore, analysis indicates that the rate of mussel population extinction has accelerated since 1970, with a recent average of two mussel river extinctions per year. 5. The predominant threat to the mussel populations has undoubtedly been pearl fishing. This has been occurring at every river, even in the most remote northwest areas, where most of the ‘functional’ populations remain. Recent legislation has provided full protection to M. margaritifera, so that all pearl harvesting is now illegal. 6. Locally, river engineering and host salmonid stock decline poses a serious threat and eutrophication has already eliminated populations in southern and eastern Scotland. 7. In every part of its global range, M. margaritifera has declined substantially and is now either threatened with extinction or is highly vulnerable. Based on recent estimates from across the species range, it appears that Scotland now probably holds at least half of the world's remaining functional M. margaritifera populations. Copyright © 2000 John Wiley & Sons, Ltd.     

Implications of fish migration and fishing mortality for marine protected area design

The Convention on Biological Diversity calls for networks of ‘representative’ MPAs, the effectiveness of which requires that the protected ecosystems be independent of external anthropogenic pressures. One principal pressure, fishing, severely depletes the oldest age classes of the target fish even if optimally managed. As many fishery resource species had high natural abundance and large individual sizes, while most fish show indeterminate growth and ascend the trophic pyramid as they grow, elimination of older age classes equates to removal of once‐dominant top predators. Because archetypal resource species are also migratory, that loss is transported throughout the range of the exploited populations, including into MPAs, through a lack of large migrants. The ecological implications remain uncertain in marine ecosystems, which are typically under ‘bottom‐up’ control. ‘Top‐down’ effects, such as mesopredator release, species replacement and trophic cascades, have been observed, however, meaning that elimination of top predators may affect ecosystem structure. It follows that, while exceptions doubtless exist, in general ‘representative’ MPAs should not be expected to fulfil their declared purposes, unless they are made so large as to encompass the whole migratory circuits of principal resource species – implying indefinite closure of the fisheries affected. Some compromise may be possible if MPAs were combined with fishing mortality rates far below current ‘optimal’ levels or where fishing can be concentrated on younger adults, while older fish are protected from exploitation. In any case, societies must choose between seafood production and recovery of selected marine areas to near‐pristine conditions.     

Lessons from the past: the collapse of Jamaican coral reefs

Since Pre-Columbian times, humans have exploited Jamaican marine ecosystems with significant consequences for flora and fauna. This study focuses on the history of reef fish exploitation in Jamaica, from first human occupation to the present day, to determine how past fishing activities contributed to subsequent declines in the coral reef ecosystem. The pattern of declining reef fish populations was nonlinear. Reef fish first declined in prehistoric times but then potentially recovered, following genocide of the native human population. Reduced fishing pressure lasted until the mid-19th century. At that time, depletion of reef fish populations again occurred with a precipitous decline from the 1850s to the 1940s. The final shift from relatively abundant to overfished marine fauna corresponded to subtle changes in fish trap design as well as development of recreational fishing. Government subsidies throughout the second half of the 20th century exacerbated the declines. This analysis shows that local artisanal fisheries with relatively low levels of effort and seemingly subtle shifts in technology can significantly impact the coral reef ecosystem and that declines occurred decades to centuries before modern ecological studies began. This research shows how historical analysis can be a powerful tool to minimize shifted baselines and establish realistic targets for recovery and sustainable management of marine ecosystems.     

Historical distribution of freshwater fishes and the reference conditions concept in a large Mediterranean basin

1. The European Water Framework Directive 2000/60/EC (WFD) defines the ecological status of aquatic systems as the deviation between their present biological state and that which would be expected in the absence of any major human disturbance, referred to by the WFD as the ‘reference condition’ (RC). It assumes that their biotic composition should remain balanced and constant over time. This study tested both assumptions against an analysis of the historical distribution of the fish fauna in a large and highly disturbed Mediterranean basin. If fish communities change substantially over time, it will mean that the validity of the RC concept comes into question.
2. Using presence/absence data for historical native fish fauna from the Guadalquivir Basin, distribution changes among sub-basins were quantified by mapping between the nineteenth century and today.
3. The range of two native species (Anguilla anguilla and Salmo trutta) has changed significantly. In addition, the diadromous species assemblage has almost become locally extinct, with the exception of the eel. Finally, most Guadalquivir sub-basins (94.7%) have suffered major changes in the composition of their fish communities, either by losing native species or by adding new non-native species.
4. These results render the definition of any RC unlikely. In Mediterranean areas, the WFD objective of ‘good ecological status’ recovery based on the integrity of aquatic communities is a theoretical rather than a real goal. Nonetheless, the WFD provides an ecological guiding principle that can also be transferred to the conservation of freshwater ecosystems.
5. As an alternative to the RC concept in Mediterranean lotic ecosystems, specific multimetric indices can be used, based on expert criteria, the metrics of which can also relate to the conservation value of water bodies, and not only to their ecological status.

     

Strong fisheries management and governance positively impact ecosystem status

Fisheries have had major negative impacts on marine ecosystems, and effective fisheries management and governance are needed to achieve sustainable fisheries, biodiversity conservation goals and thus good ecosystem status. To date, the IndiSeas programme (Indicators for the Seas) has focussed on assessing the ecological impacts of fishing at the ecosystem scale using ecological indicators. Here, we explore fisheries ‘Management Effectiveness’ and ‘Governance Quality’ and relate this to ecosystem health and status. We developed a dedicated expert survey, focused at the ecosystem level, with a series of questions addressing aspects of management and governance, from an ecosystem‐based perspective, using objective and evidence‐based criteria. The survey was completed by ecosystem experts (managers and scientists) and results analysed using ranking and multivariate methods. Results were further examined for selected ecosystems, using expert knowledge, to explore the overall findings in greater depth. Higher scores for ‘Management Effectiveness’ and ‘Governance Quality’ were significantly and positively related to ecosystems with better ecological status. Key factors that point to success in delivering fisheries and conservation objectives were as follows: the use of reference points for management, frequent review of stock assessments, whether Illegal, Unreported and Unregulated (IUU) catches were being accounted for and addressed, and the inclusion of stakeholders. Additionally, we found that the implementation of a long‐term management plan, including economic and social dimensions of fisheries in exploited ecosystems, was a key factor in successful, sustainable fisheries management. Our results support the thesis that good ecosystem‐based management and governance, sustainable fisheries and healthy ecosystems go together.     

Palaeoecological insights for the conservation of aquatic ecosystems in dryland environments: A case study of the Verlorenvlei system,South Africa

Verlorenvlei, a dryland aquatic ecosystem in South Africa, has been identified as having enormous conservation importance. Although the system has Ramsar status and is widely regarded as being in ‘pristine' condition, neither statutory control nor any form of management is currently in existence. Based on the analysis of fossil pollen derived from the sediments of Verlorenvlei, a sequence of rapid changes within the riparian and aquatic vegetation is identified. Synchronous changes in the rate of sedimentation suggest a threefold increase in annual sediment deposition since the mid-18th century—the onset of colonial settlement. The pollen spectra prior to the arrival of colonial settlers suggest that abundant Poaceae (grasses) and rooted aquatic plants dominated the vegetation of the site. Radical changes in the pollen record become evident after the time of European colonization. Aquatic vegetation, including Gentianaceae (water lilies) and Potamogetonaceae, show a marked decrease while riparian vegetation, particularly reed elements such as Cyperaceae, Typhaceae and Juncaceae, are seen to increase progressively. Terrestrial pollen indicators reveal an expansion in the vegetation of classic disturbance indicators such as Asteraceae, Oxalidaceae and Scrophulariaceae. As the wetland has already endured rapid ecological adjustments in the face of colonial (and more recent) occupation of the broader landscape, it cannot be regarded as being in a ‘pristine’ state. Indeed, Verlorenvlei is interpreted as having reached a state of ‘transitional’ ecological equilibrium in which it continues to endure a number of rapid ecological changes; nonetheless, it is still worthy of conservation and management, not least because of its role as a strategic wetland in a dryland environment. Failing the timely implementation of remedial action in the form of an integrated conservation and management plan, Verlorenvlei appears destined to become irreversibly altered. Dryland aquatic ecosystems are vital aquatic resources in so called ‘Third World’ regions of the world yet, paradoxically, scientific research on, and the conservation of, these environments in the Southern Hemisphere are rare by comparison to wetland environments in the northern temperate zones. Although many dryland aquatic systems may already be altered, most are worthy of urgent management and conservation action, bearing in mind the fundamental question: ‘What is it that we wish to conserve?’. A number of recommendations for the management of dryland aquatic ecosystems such as Verlorenvlei are listed.     

The contribution of cephalopods to global marine fisheries: can we have our squid and eat them too?

Cephalopods are a key component of marine food webs, providing sustenance for myriad marine species. Cephalopods are also of increasing economic importance as evidenced by the rapid rise in their global landings over recent decades. If fisheries continue on this trajectory, conflicts may transpire among cephalopod and finfish fisheries, particularly in ecosystems where cephalopods are highly valuable both directly as a landed commodity and indirectly as prey for other harvested species. We provide the first measure of the ecosystem services that cephalopods contribute to fisheries in 28 marine ecosystems, both as a commodity and an ecological support service. We also evaluate how current demands on cephalopods compare to mid‐20th century conditions. We find that cephalopod contributions to fisheries vary widely, but are substantial in many ecosystems. Commodity and supportive services provided by cephalopods contributed as much as 55% of fishery landings (tonnes) and 70% of landed values ($USD). The contribution of cephalopods as a commodity was generally greatest in the coastal ecosystems, whereas their contribution as a supportive service was highest in open ocean systems. Further, the commodity and supportive services provided by cephalopods to fisheries landings increased in most of the coastal ecosystems between the mid‐20th century (years 1960–70) and contemporary periods (years 1990–2004), indicating the rising demand for cephalopods. Current demands have no historical precedent and ecosystems in which cephalopods are highly exploited as a targeted resource and as an ecological support service should be further evaluated to prevent the unsustainable development of marine fisheries within them.     

Perception of a cetacean mass stranding in Italy: the emergence of compassion

• 1 The view that whales are malicious monsters has been pervasive throughout history. Conversely, the idea that these animals experience suffering has emerged only recently. One way of investigating perceptual, as well as behavioural, shifts is assessing general public reactions to mortality events involving wild, rare and charismatic animals.
• 2 Here, the responses of 118 individuals to questions regarding the mass stranding of seven sperm whales (Physeter macrocephalus) along the Adriatic Sea coast of Italy in December 2009 are reported through interviews taken at the stranding site and in the direct proximity of the dead animals.
• 3 When asked why the whales were stranded, 44.1% of the respondents suggested anthropogenic causes and 21.2% non‐anthropogenic. The remaining 34.7% mentioned a generic ‘disorientation’ or stated they did not know. When asked how they felt about the whales, 68.6% expressed feelings of compassion or care towards the animals. Clearly non‐compassionate attitudes accounted for only 4.1% of the sample. Finally, 21.2% expressed feelings that were ambiguous in terms of being suggestive of compassionate or non‐compassionate attitudes, including 11.9% amazement, 4.2% deprecation and 5.1% powerlessness.
• 4 These results are in stark contrast with information obtained from accounts of similar events that have occurred in historical times, up until the first half of the 20th century. For centuries, responses to cetacean live strandings—typically including killing and harming of the animals—were either utilitarian or characterized by feelings including fear and a desire to ‘subjugate the beast’, with no apparent concern for their suffering and death.
• 5 It is concluded that attitudes towards whales—today strikingly revolving around sadness, compassion and a sense of loss—have changed dramatically over time, with a steep turnaround in the 1970/1980s. Full appreciation of the ongoing evolution in public perception can channel marine conservation efforts and assist in the design of response strategies to marine mammal strandings. Copyright © 2010 John Wiley & Sons, Ltd.

     

Prioritizing action for recovery and conservation of marine species: a case study based on species of conservation importance around England

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A new record of the freshwater pearl mussel Margaritifera margaritifera L. (Bivalvia,Unionoida) from the River Narcea (Asturias,north‐western Spain)

1. A population of the freshwater pearl mussel Margaritifera margaritifera L. was found in the River Narcea in the province of Asturias (north‐western Spain). Primary analysis of the population shows that it is well distributed along the river and is particularly abundant in shady river banks with a gravel substrate. 2. The length of living mussels ranges between a minimum of 22 mm and a maximum of 116 mm, with most in the size class between 65 mm and 70 mm. There is a good proportion of young mussels, although no fertile females were found in the course of the investigation. 3. Although there is no specific legislation in Spain for the protection of M. margaritifera, it has recently been proposed to include M. margaritifera in the Spanish List of Threatened Species as ‘vulnerable’. 4. Although the River Narcea seems to provide suitable conditions for the pearl mussel (water quality, available salmonid hosts, etc.), the main conservation measures must be directed at avoiding river fragmentation from dams, channelization and organic enrichment from individual farms or towns situated close to the river bank. Copyright © 2000 John Wiley & Sons, Ltd.     

Using fishers' anecdotes, naturalists' observations and grey literature to reassess marine species at risk: the case of the Gulf grouper in the Gulf of California, Mexico

Designing fishing policies without knowledge of past levels of target species abundance is a dangerous omission for fisheries management. However, as fisheries monitoring started long after exploitation of many species began, this is a difficult issue to address. Here we show how the ‘shifting baseline’ syndrome can affect the stock assessment of a vulnerable species by masking real population trends and thereby put marine animals at serious risk. Current fishery data suggest that landings of the large Gulf grouper (Mycteroperca jordani, Serranidae) are increasing in the Gulf of California. However, reviews of historical evidence, naturalists’ observations and a systematic documentation of fishers’ perceptions of trends in the abundance of this species indicate that it has dramatically declined. The heyday for the Gulf grouper fishery occurred prior to the 1970s, after which abundance dropped rapidly, probably falling to a few percent of former numbers. This decline happened long before fishery statistics were formally developed. We use the case of the Gulf grouper to illustrate how other vulnerable tropical and semi‐tropical fish and shellfish species around the world may be facing the same fate as the Gulf grouper. In accordance with other recent studies, we recommend using historical tools as part of a broad data‐gathering approach to assess the conservation status of marine species that are vulnerable to over‐exploitation.     

Review of climate change impacts on marine fisheries in the UK and Ireland

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Alien turf: Overfishing,overgrazing and invader domination in south‐eastern Levant reef ecosystems

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Primary productivity demands of global fishing fleets

To be sustainable, the extractive process of fishing requires biomass renewal via primary production driven by solar energy. Primary production required (PPR) estimates how much primary production is needed to replace the biomass of fisheries landings removed from marine ecosystems. Here, we examine the historical fishing behaviour of global fishing fleets, which parts of the food web they rely on, which ecosystems they fish and how intensively. Highly mobile European and Asian fleets have moved to ever more distant productive waters since the 1970s, especially once they are faced with the costs of access agreements for exclusive economic zones (EEZs) declared by host countries. We examine fleet PPR demands in the context of large marine ecosystems (LMEs), which are frequently fished with PPR demands well above their average primary productivity (PP). In some cases, this was mitigated by subsequent emigration of fleets or by management intervention. Fleet movements, however, have stressed additional marine areas, including the EEZs of developing countries. This suggests the potential for spatial serial depletion, if fishing capacity is not reduced to more sustainable PP removal levels. Fundamentally, fishing is limited by solar‐powered PP limits. Fishing beyond solar production has occurred, but in the future, marine systems may not be as forgiving, especially if overfishing and climate change compromise their resilience.     

Looking beyond the horizon: An early warning system to keep marine mammal information relevant for conservation

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Reconstructing 290 years of a data‐poor fishery through ethnographic and archival research: The East Pacific green turtle (Chelonia mydas) in Baja California,Mexico

Evaluating historical changes in the exploitation of marine organisms is a key challenge in fisheries ecology and marine conservation. In the Eastern Pacific, marine turtles were exploited for millennia before systematic monitoring began <50 years ago. Using ethnographic and historical data, we generated a detailed reconstruction of the East Pacific green sea turtle (Chelonia mydas) fishery in Mexico's Baja California peninsula from 1700 to 1990. Sea turtles from the region's important feeding areas were a staple food source from the earliest phases of human occupation, dating back at least 12,000 years. In contrast with regions such as the Caribbean, small human populations and limited market access resulted in apparently sustainable turtle harvests until the second half of the 20th century. We found that the estimated annual catches between 1960 and 1980 exceeded the estimated annual catches of the previous 250 years by an order of magnitude, leading to the collapse of the fishery and the depletion of the green turtle population. A total ban on sea turtle captures in 1990, comprehensive nesting beach protection, and significant conservation efforts resulted in increases in breeding females on nesting beaches and catch rates in scientific monitoring on main feeding grounds since the early 2000s. This provides a positive outlook for this once‐depleted population segment. Although further research is needed to evaluate current conservation status, we have identified a date, between 1950 and 1960, which can serve as a reliable temporal reference for future evaluations of historical baseline abundance in this region.     

Adverse feedback sequences in exploited marine systems: are deliberate interruptive actions warranted?

Several mechanisms for self‐enhancing feedback instabilities in marine ecosystems are identified and briefly elaborated. It appears that adverse phases of operation may be abruptly triggered by explosive breakouts in abundance of one or more previously suppressed populations. Moreover, an evident capacity of marine organisms to accomplish extensive geographic habitat expansions may expand and perpetuate a breakout event. This set of conceptual elements provides a framework for interpretation of a sequence of events that has occurred in the Northern Benguela Current Large Marine Ecosystem (off south‐western Africa). This history can illustrate how multiple feedback loops might interact with one another in unanticipated and quite malignant ways, leading not only to collapse of customary resource stocks but also to degradation of the ecosystem to such an extent that disruption of customary goods and services may go beyond fisheries alone to adversely affect other major global ecosystem concerns (e.g. proliferations of jellyfish and other slimy, stingy, toxic and/or noxious organisms, perhaps even climate change itself, etc.). The wisdom of management interventions designed to interrupt an adverse mode of feedback operation is pondered. Research pathways are proposed that may lead to improved insights needed: (i) to avoid potential ‘triggers’ that might set adverse phases of feedback loop operation into motion; and (ii) to diagnose and properly evaluate plausible actions to reverse adverse phases of feedback operation that might already have been set in motion. These pathways include the drawing of inferences from available ‘quasi‐experiments’ produced either by short‐term climatic variation or inadvertently in the course of biased exploitation practices, and inter‐regional applications of the comparative method of science.     

A review of climate change and the implementation of marine biodiversity legislation in the United Kingdom

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