Showing results for: Marine and aquatic ecosystems
Fisheries often discard large quantities of unwanted catches at sea, but policies are being brought in to limit such discards. According to this paper, Northern gannets (seabirds) rely more on fishery discards in years when there are shortages in their natural prey (mainly mackerel) - shortages that may be due to pressure from fisheries. The paper argues that fishery discards are not an adequate substitute for natural prey.
Following consultation with fishers and marine conservation experts, the UK government has created new Marine Conservation Zones around the English coast, taking the UK’s total protected areas of ocean to over twice the size of England. However, some critics question whether the protected areas are actually beneficial to wildlife.
Human-induced environmental change could lead to the collapse of social and economic systems, according to this report from the UK think-tank IPPR, which argues that policymakers must shift their understanding of the scale and impacts of environmental breakdown and the need for transformative change.
The Pacific Coast Federation of Fishermen's Associations has taken legal action against 30 fossil fuel companies, arguing that the crab fishing industry is being harmed by climate change. Algal blooms, made more likely by warming ocean waters, have cut short crab fishing seasons.
The vast majority of industrial fishing (defined as fishing vessels of over 24 metres) is done by vessels that are registered to relatively wealthy countries, according to a recent paper. Vessels registered to high income and upper middle income countries (according to World Bank classifications) accounted for 97% of industrial fishing effort in international waters and 78% of industrial fishing effort in the national waters of poorer countries. China, Taiwan, Japan, South Korea, and Spain together account for most of the fishing effort.
Fishers increase their fishing activity prior to the establishment of a new marine reserve, a new paper claims. The study used satellite data to study one particular marine reserve, the Phoenix Islands Protected Area (PIPA). While fishing effort dropped to almost zero after the marine reserve was established, fishing effort prior to the reserve’s establishment was 130% higher than in a control region (where no reserve was planned).
Attaching green light emitting diodes (LEDs) to gillnets (vertical fishing nets that catch fish behind the gills) reduces the number of guanay cormorants accidentally caught by 85% relative to control nets with no lights, reports a recent paper. A previous study of the same fishery has shown that illuminating nets can reduce bycatch of green turtles by 64% without reducing catch rates of the target species (the current paper did not specify catch rates of the target species). The authors hypothesise that it may be possible to tailor the wavelength of light to attract or repel specific species, according to a fishery’s needs.
The first systematic analysis of marine wilderness around the world finds that only 13% of the ocean can still be classed as wilderness, i.e. having experienced low impacts from human-caused stressors such as fertilizer runoff, fishing and climate change. Only 4.9% of that wilderness (covering 0.6% of total ocean area) falls within official marine protected areas.
The FAO has released its 2018 report on world fishery and aquaculture statistics. Key findings include that fisheries output peaked in 2016, having remained approximately static since the late 1980s, while aquaculture production is rising, as shown in the figure below. In 2015, fish accounted for around 17% of global animal protein consumption. One third of fish stocks are currently overfished, although progress has been made in the United States and Australia in increasing the proportion of fish stocks that are sustainably fished.
Structural changes in the food system such as replacing half of animal proteins with plant-based proteins could significantly marine eutrophication in the North-East Atlantic, according to a recent paper. The authors addressed the question of whether Western Europe can reduce nitrogen and phosphorus runoff to coastal areas without endangering food security.
A report by WWF, The Rivers Trust and The Angling Trust finds that only 14% of rivers in England are classed as healthy, with damage being caused by poor farming and land management practices, for example by degraded soil being washed into watercourses and agricultural chemicals contaminating groundwater. The report sets out a strategy for managing both soil and water health, including stricter control of slurry storage, incentives for farmers to plant woodland or create wetland habitats and creating an advice service for farmers and land managers.
In this TED talk, ocean expert Nancy Rabalais discusses the “dead zone” in the Gulf of Mexico - an area of the ocean where there isn’t enough oxygen to support sea life. Fertiliser runoff from farmland further up the Mississippi River is causing the dead zone, according to Rabalais. She says that solutions could include growing perennial grains and using precision fertilisation.
Many important marine species, including marine mammals, sea turtles and seabirds, are threatened by bycatch - i.e. being accidentally caught by fishers who are targeting other species. A new paper finds that around half of the populations threatened by bycatch could be protected by managing fish stocks to maximise fishery profits, which would reduce bycatch as a side-effect of reducing overfishing.
This book, edited by Faisal I. Hai, Chettiyappan Visvanathan and Ramaraj Boopathy, discusses the social, economic and environmental sustainability implications of various aquaculture practices.
This paper presents the findings of a large-scale study which used global tracking data on sea-going vessels to characterise the scale, distribution and drivers of the global fishing effort.
The planetary boundaries concept provides a theoretical upper limit on human activity which the planet is able to sustain without major perturbation to the current ‘Earth system’. Previously, nine planetary boundaries (PBs) have been proposed and recently Steffen et al. (2015) have updated these boundary definitions and assessed the current state of the position of human activity with respect to each boundary. In this article, researchers from a number of food, climate change, agricultural and environmental research institutions around the world build on this work by assessing the impact of agriculture on each PB status, based on a detailed literature review of the available research.