Sustainable fishery
Some primary concerns around sustainability are that heavy fishing pressures, such as overexploitation and growth or recruitment overfishing, will result in the loss of significant potential yield; that stock structure will erode to the point where it loses diversity and resilience to environmental fluctuations; that ecosystems and their economic infrastructures will cycle between collapse and recovery; with each cycle less productive than its predecessor; and that changes will occur in the trophic balance (fishing down marine food webs).
[2] Global wild fisheries are believed to have peaked and begun a decline, with valuable habitats, such as estuaries and coral reefs, in critical condition.
[2] Humans have been operating such regimes for thousands of years, transforming many ecosystems, depleting or driving to extinction many species.
This might include diesel fuel for the fishing ships and boats: there is even a debate about the long term sustainability of biofuels.
Comparing fisheries and mineral extraction tells us that human pressure on the environment is causing a wide range of resources to go through a Hubbert depletion cycle.
Repeated bottom trawling and dredging literally flattens diversity in the benthic habitat, radically changing the associated communities.
This reduces sustainable catch levels across many habitats, puts pressure on resources needed for aquaculture, on the communities that depend on fisheries, and on the oceans' ability to capture and store carbon (biological pump).
Sea level rise puts coastal fishing communities at risk, while changing rainfall patterns and water use impact on inland (freshwater) fisheries and aquaculture.
As climate change causes oceans to warm up, fish are forced to move away, into cooler Northern waters.
The United Nations Environment Programme (UNEP) mapped the impacts of stressors such as climate change, pollution, exotic species, and over-exploitation of resources on the oceans.
[27][28][29] Large predator fish can contain significant amounts of mercury, a neurotoxin which can affect fetal development, memory, mental focus, and produce tremors.
... fish communities can be altered in a number of ways, for example they can decrease if particular-sized individuals of a species are targeted, as this affects predator and prey dynamics.
Fishing, however, is not the sole cause of changes to marine life—pollution is another example.... No one factor operates in isolation and components of the ecosystem respond differently to each individual factor.The traditional approach to fisheries science and management has been to focus on a single species.
[42] In a 2007 effort to "stimulate much needed discussion" and "clarify the essential components" of ecosystem-based fisheries science, a group of scientists offered the following ten commandments for ecosystem-based fisheries scientists:[43] Strategies and techniques for marine conservation tend to combine theoretical disciplines, such as population biology, with practical conservation strategies, such as setting up protected areas, as with Marine Protected Areas (MPAs) or Voluntary Marine Conservation Areas.
Each nation defines MPAs independently, but they commonly involve increased protection for the area from fishing and other threats.
Daniel Pauly characterises marine protected areas as "a conservation tool of revolutionary importance that is being incorporated into the fisheries mainstream.
"[12] The Pew Charitable Trusts have funded various initiatives aimed at encouraging the development of MPAs and other ocean conservation measures.
", then answered his own question, "By accepting each other's essentials: that fishing should remain a viable occupation; and that aquatic ecosystems and their biodiversity are allowed to persist.
An example is the large ranch Veta La Palma in Spain's Guadalquivir Marshes, which for some years had a productive fishery.
Various organizations promote sustainable fishing strategies, educate the public and stakeholders, and lobby for conservation law and policy.
The list includes the Marine Conservation Biology Institute and Blue Frontier Campaign in the U.S., The U.K.'s Frontier (The Society for Environmental Exploration) and Marine Conservation Society, Australian Marine Conservation Society, International Council for the Exploration of the Sea (ICES), Langkawi Declaration, Oceana, PROFISH, and the Sea Around Us Project, International Collective in Support of Fishworkers, World Forum of Fish Harvesters and Fish Workers, Frozen at Sea Fillets Association and CEDO.
Some organizations certify fishing industry players for sustainable or good practices, such as the Marine Stewardship Council and Friend of the Sea.
According to the marine conservation biologist Callum Roberts, four criteria apply when choosing seafood:[52] The following organizations have download links for wallet-sized cards, listing good and bad choices:[53] The United Nations Millennium Development Goals (MDGs) include, as goal number 7: target 2, the intention to "reduce biodiversity loss, achieving, by 2010, a significant reduction in the rate of loss", including improving fisheries management to reduce depletion of fish stocks.
Areas that swarmed with a particular species hundreds of years ago, may have experienced long-term decline, but it is the level of decades previously that is considered the appropriate reference point for current populations.
The United States Fish Commission was established 12 years earlier for the purpose of finding why fisheries in New England were declining.
[69] Traditionally, fisheries management and the science underpinning it was distorted by its "narrow focus on target populations and the corresponding failure to account for ecosystem effects leading to declines of species abundance and diversity" and by perceiving the fishing industry as "the sole legitimate user, in effect the owner, of marine living resources."
