Considering land-sea interactions and trade-offs for food and biodiversity

A database of mapped global fishing activity 1950-2017

A new database on historical country-level fishing fleet capacity and effort is described, derived from a range of publicly available sources that were harmonized, converted to fishing effort, and mapped to 30-min spatial cells. The resulting data is comparable with widely used but more temporally-limited satellite-sourced Automatic Identification System (AIS) datasets for large vessels, while also documenting important smaller fleets and artisanal segments. It ranges from 1950 to 2017, and includes information on number of vessels, engine power, gross tonnage, and nominal effort, categorized by vessel length, gear type and targeted functional groups. The data can be aggregated to Large Marine Ecosystem, region and/or fishing country scales and provides a temporally and spatially explicit source for fishing effort and fleet capacity for studies aimed at understanding the implications of long-term changes in fishing activity in the global ocean.

On the wrong track: Sustainable and low-emission blue food diets to mitigate climate change

Seafood and other aquatic food (blue food) are often advocated as sustainable protein sources crucial to meeting global food demand. Consumption choices allow citizens to take actions that reduce the environmental burden of food production and tackle the climate crisis. Here we used a high-resolution Spanish national-level dataset collected from 12,500 households between 1999 and 2021 as a study case to assess trends in blue food consumption concerning sources, types and stressors resulting from their production. By aggregating species groups according to source, we found an overall reduction in the consumption of most wild species. For farmed species, we found a pronounced increase in the consumption of carnivorous fish and an overall decrease in low trophic-level species consumption, such as bivalves. Using published studies, we estimated greenhouse gases, nitrogen, and phosphorus emissions to assess trends in environmental footprint. Low performance was associated with the consumption of high trophic-level species intensively farmed in distant regions, such as carnivorous fish, due to high stressor emissions related to their production and transport. Across all groups, consumption of locally farmed bivalves conduced to the lowest stressor emissions, providing an example of ‘net-zero' blue food. Our analysis identified historical trends in the environmental footprint of blue food consumption and consumers' choices that promote environmentally sustainable diets. It also highlights vast differences in the ecological footprint associated with the consumption of aquaculture-sourced protein. Based on our assessment, we recommend refocusing consumption patterns toward farmed species with small environmental footprints, such as locally produced low trophic-level species, and implementing policies that increase consumers' environmental awareness and minimize food production systems' footprints. Considering global blue food demand is predicted to nearly double by mid-century, consumers' choices can significantly impact sustainable production practices and mitigate climate change.

Resource users as land-sea links in coastal and marine socioecological systems

Coastal zones, which connect terrestrial and aquatic ecosystems, are among the most resource-rich regions globally and home to nearly 40% of the global human population. Because human land-based activities can alter natural processes in ways that affect adjacent aquatic ecosystems, land-sea interactions are increasingly recognized as critical to coastal conservation planning and governance. However, the complex socioeconomic dynamics inherent in coastal and marine socioecological systems (SESs) have received little consideration. Drawing on knowledge generalized from long-term studies in Caribbean Nicaragua, we devised a conceptual framework that clarifies the multiple ways socioeconomically driven behavior can link the land and sea. In addition to other ecosystem effects, the framework illustrates how feedbacks resulting from changes to aquatic resources can influence terrestrial resource management decisions and land uses. We assessed the framework by applying it to empirical studies from a variety of coastal SESs. The results suggest its broad applicability and highlighted the paucity of research that explicitly investigates the effects of human behavior on coastal SES dynamics. We encourage researchers and policy makers to consider direct, indirect, and bidirectional cross-ecosystem links that move beyond traditionally recognized land-to-sea processes.

Seafood in Food Security: A Call for Bridging the Terrestrial-Aquatic Divide

The contribution of seafood to global food security is being increasingly highlighted in policy. However, the extent to which such claims are supported in the current food security literature is unclear. This review assesses the extent to which seafood is represented in the recent food security literature, both individually and from a food systems perspective, in combination with terrestrially-based production systems. The results demonstrate that seafood remains under-researched compared to the role of terrestrial animal and plant production in food security. Furthermore, seafood and terrestrial production remain siloed, with very few papers addressing the combined contribution or relations between terrestrial and aquatic systems. We conclude that far more attention is needed to the specific and relative role of seafood in global food security and call for the integration of seafood in a wider interdisciplinary approach to global food system research.

Oceans and society: feedbacks between ocean and human health

The concentration of human population along coastlines has far-reaching effects on ocean and societal health. The oceans provide benefits to humans such as food, coastal protection and improved mental well-being, but can also impact negatively via natural disasters. At the same time, humans influence ocean health, for example, via coastal development or through environmental stewardship. Given the strong feedbacks between ocean and human health there is a need to promote desirable interactions, while minimising undesirable interactions. To this end, we articulate two scenarios for 2030. First, Business-as-Usual, named 'Command and (out of) Control', focuses on the anticipated future based on our current trajectory. Second, a more sustainable scenario called 'Living and Connecting', emphasises the development of interactions between oceans and society consistent with achieving the Sustainable Development Goals. We describe a potential pathway to achieving the 'Living and Connecting' scenario, centred on improving marine citizenship, achieving a more equitable distribution of power among stakeholders, and more equitable access to resources and opportunities. The constituent actions of this pathway can be categorised into four groups: (i) improved approaches to science and health communication that account for society's diverse values, beliefs and worldviews, (ii) a shift towards more trusted relationships among stakeholders to enable two-way knowledge exchange, (iii) economic incentives that encourage behavioural changes necessary for achieving desired sustainability outcomes, and (iv) stronger regulations that simultaneously focus on ocean and human health. We contend that these changes will provide improved outcomes for both oceans and society over the United Nations Decade of Ocean Science.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11160-021-09669-5.

Oceans and society: feedbacks between ocean and human health

The concentration of human population along coastlines has far-reaching effects on ocean and societal health. The oceans provide benefits to humans such as food, coastal protection and improved mental well-being, but can also impact negatively via natural disasters. At the same time, humans influence ocean health, for example, via coastal development or through environmental stewardship. Given the strong feedbacks between ocean and human health there is a need to promote desirable interactions, while minimising undesirable interactions. To this end, we articulate two scenarios for 2030. First, Business-as-Usual, named 'Command and (out of) Control', focuses on the anticipated future based on our current trajectory. Second, a more sustainable scenario called 'Living and Connecting', emphasises the development of interactions between oceans and society consistent with achieving the Sustainable Development Goals. We describe a potential pathway to achieving the 'Living and Connecting' scenario, centred on improving marine citizenship, achieving a more equitable distribution of power among stakeholders, and more equitable access to resources and opportunities. The constituent actions of this pathway can be categorised into four groups: (i) improved approaches to science and health communication that account for society's diverse values, beliefs and worldviews, (ii) a shift towards more trusted relationships among stakeholders to enable two-way knowledge exchange, (iii) economic incentives that encourage behavioural changes necessary for achieving desired sustainability outcomes, and (iv) stronger regulations that simultaneously focus on ocean and human health. We contend that these changes will provide improved outcomes for both oceans and society over the United Nations Decade of Ocean Science.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11160-021-09669-5.

The biology and ecology of the banana prawns: Penaeus merguiensis de Man and P. indicus H. Milne Edwards

The two banana prawns Penaeus merguiensis and P. indicus are arguably the most commercially important species of penaeid prawns in the tropical and sub-tropical Indo-West Pacific region. They are fecund, short-lived, and have a complex life history involving offshore spawning, inshore mangrove-lined nursery grounds, and migrations between the two locations. We have reviewed and assessed published research on: the fisheries and aquaculture; taxonomy and identification; distribution and habitat preferences; growth; mortality; food and feeding; predation, and the importance of the mangrove habitat to banana prawns. We have examined the life history patterns of these two banana prawns and the many environmental and biological factors that affect different life history stages, often resulting in large interannual variations in abundances of adult prawns and commercial catches. We have also reviewed research on the ecosystem relationships involving these prawns, including fishery impacts on the environment and other species caught as bycatch. In reviewing the published information on factors affecting recruitment dynamics and variability, we have sometimes found contrasting and confounding results, suggesting that these factors are not yet fully understood. Therefore, for each aspect of the prawns' biology we have pointed to areas with incomplete or conflicted understanding, which will hopefully guide future research on these extremely valuable prawn species.

Escaping the perfect storm of simultaneous climate change impacts on agriculture and marine fisheries

Climate change can alter conditions that sustain food production and availability, with cascading consequences for food security and global economies. Here, we evaluate the vulnerability of societies to the simultaneous impacts of climate change on agriculture and marine fisheries at a global scale. Under a "business-as-usual" emission scenario, ~90% of the world's population-most of whom live in the most sensitive and least developed countries-are projected to be exposed to losses of food production in both sectors, while less than 3% would live in regions experiencing simultaneous productivity gains by 2100. Under a strong mitigation scenario comparable to achieving the Paris Agreement, most countries-including the most vulnerable and many of the largest CO₂ producers-would experience concomitant net gains in agriculture and fisheries production. Reducing societies' vulnerability to future climate impacts requires prompt mitigation actions led by major CO₂ emitters coupled with strategic adaptation within and across sectors.

Evolution of global marine fishing fleets and the response of fished resources

Previous reconstructions of marine fishing fleets have aggregated data without regard to the artisanal and industrial sectors. Engine power has often been estimated from subsets of the developed world, leading to inflated results. We disaggregated data into three sectors, artisanal (unpowered/powered) and industrial, and reconstructed the evolution of the fleet and its fishing effort. We found that the global fishing fleet doubled between 1950 and 2015-from 1.7 to 3.7 million vessels. This has been driven by substantial expansion of the motorized fleet, particularly, of the powered-artisanal fleet. By 2015, 68% of the global fishing fleet was motorized. Although the global fleet is dominated by small powered vessels under 50 kW, they contribute only 27% of the global engine power, which has increased from 25 to 145 GW (combined powered-artisanal and industrial fleets). Alongside an expansion of the fleets, the effective catch per unit of effort (CPUE) has consistently decreased since 1950, showing the increasing pressure of fisheries on ocean resources. The effective CPUE of most countries in 2015 was a fifth of its 1950s value, which was compared with a global decline in abundance. There are signs, however, of stabilization and more effective management in recent years, with a reduction in fleet sizes in developed countries. Based on historical patterns and allowing for the slowing rate of expansion, 1 million more motorized vessels could join the global fleet by midcentury as developing countries continue to transition away from subsistence fisheries, challenging sustainable use of fisheries' resources.