A shifting baseline (also known as a sliding baseline) is a type of change to how a system is measured, usually against previous reference points (baselines), which themselves may represent significant changes from an even earlier state of the system that fails to be considered or remembered.
The concept arose in landscape architect Ian McHarg's 1969 manifesto Design With Nature [1] in which the modern landscape is compared to that on which ancient people once lived.
The concept was then considered by the fisheries scientist Daniel Pauly in his paper "Anecdotes and the shifting baseline syndrome of fisheries". [2] Pauly developed the concept in reference to fisheries management where fisheries scientists sometimes fail to identify the correct "baseline" population size (e.g. how abundant a fish species population was before human exploitation) and thus, wind up working with a shifted baseline. He describes the way that radically depleted fisheries were evaluated by experts who used the state of the fishery at the start of their careers as the baseline, rather than the fishery in its untouched natural state. 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. In this way large declines in ecosystems or species over long periods of time were, and are, masked. There is a loss of perception of change that occurs when each generation redefines what is "natural".
Stock assessments by most modern fisheries do not ignore historical fishing and account for it by either including the historical catch or use other techniques to reconstruct the depletion level of the population at the start of the period for which adequate data is available. Anecdotes about historical population levels may be highly unreliable and result in severe mismanagement of the fishery. [3] [4]
The concept was further refined and applied to the ecology of kelp forests by Paul Dayton and others from the Scripps Institution of Oceanography. They used a slightly different version of the term in their paper, "Sliding baselines, ghosts, and reduced expectations in kelp forest communities". [5] Both terms refer to a shift over time in the expectation of what a healthy ecosystem baseline looks like.
In 2002, filmmaker and former marine biologist Randy Olson broadened the definition of shifting baselines with an op-ed in the Los Angeles Times . He explained the relevance of the concept to all aspects of change and the failure to notice change in the world today. He and Jeremy Jackson, a coral reef ecologist, co-founded The Shifting Baselines Ocean Media Project in 2003 to help promote a wider understanding and use of the concept in conservation policy.[ citation needed ]
The Shifting Baselines Ocean Media Project grew from its three founding partners (Scripps Institution of Oceanography, The Ocean Conservancy, [6] and Surfrider Foundation) to more than twenty conservation groups and science organizations. The project has produced dozens of short films, public service announcements, and Flash videos along with photography, video, and stand-up comedy contests, all intended to promote understanding of the term to a broader audience. The Shifting Baselines Blog, "the cure for planetary amnesia" is run by the Shifting Baselines Ocean Media Project on the Seed (magazine) Science Blogs.[ citation needed ]
In 2024, Nautilus Quarterly published an article exemplifying that this effect may occur with each human generational advancement when knowledge of changes to nature that have occurred before their personal perceptions, is forgotten or lost and an inaccurate baseline is adopted. [7]
The concept has been broadened further, to apply also to underappreciated, slowly-occurring positive change by Mark Henry who labelled it "Progress Attention Deficit", [8] having the potential for application to both negative and positive differences between incorrectly perceived baselines and accurately perceived baselines.
The Channel Islands National Marine Sanctuary is a sanctuary off the coast of Santa Barbara and Ventura counties in Southern California 350 miles (563 km) south of San Francisco and 95 miles (153 km) north of Los Angeles. It was designated on October 2, 1980, by the National Oceanic and Atmospheric Administration and was expanded in 2007.
A conventional idea of a sustainable fishery is that it is one that is harvested at a sustainable rate, where the fish population does not decline over time because of fishing practices. Sustainability in fisheries combines theoretical disciplines, such as the population dynamics of fisheries, with practical strategies, such as avoiding overfishing through techniques such as individual fishing quotas, curtailing destructive and illegal fishing practices by lobbying for appropriate law and policy, setting up protected areas, restoring collapsed fisheries, incorporating all externalities involved in harvesting marine ecosystems into fishery economics, educating stakeholders and the wider public, and developing independent certification programs.
Daniel Pauly is a French-born marine biologist, well known for his work in studying human impacts on global fisheries and in 2020 was the most cited fisheries scientist in the world. He is a professor and the project leader of the Sea Around Us initiative at the Institute for the Oceans and Fisheries at the University of British Columbia. He also served as Director of the UBC Fisheries Centre from November 2003 to October 2008.
Fisheries science is the academic discipline of managing and understanding fisheries. It is a multidisciplinary science, which draws on the disciplines of limnology, oceanography, freshwater biology, marine biology, meteorology, conservation, ecology, population dynamics, economics, statistics, decision analysis, management, and many others in an attempt to provide an integrated picture of fisheries. In some cases new disciplines have emerged, as in the case of bioeconomics and fisheries law. Because fisheries science is such an all-encompassing field, fisheries scientists often use methods from a broad array of academic disciplines. Over the most recent several decades, there have been declines in fish stocks (populations) in many regions along with increasing concern about the impact of intensive fishing on marine and freshwater biodiversity.
Kelp forests are underwater areas with a high density of kelp, which covers a large part of the world's coastlines. Smaller areas of anchored kelp are called kelp beds. They are recognized as one of the most productive and dynamic ecosystems on Earth. Although algal kelp forest combined with coral reefs only cover 0.1% of Earth's total surface, they account for 0.9% of global primary productivity. Kelp forests occur worldwide throughout temperate and polar coastal oceans. In 2007, kelp forests were also discovered in tropical waters near Ecuador.
Regime shifts are large, abrupt, persistent changes in the structure and function of ecosystems, the climate, financial systems or other complex systems. A regime is a characteristic behaviour of a system which is maintained by mutually reinforced processes or feedbacks. Regimes are considered persistent relative to the time period over which the shift occurs. The change of regimes, or the shift, usually occurs when a smooth change in an internal process (feedback) or a single disturbance triggers a completely different system behavior. Although such non-linear changes have been widely studied in different disciplines ranging from atoms to climate dynamics, regime shifts have gained importance in ecology because they can substantially affect the flow of ecosystem services that societies rely upon, such as provision of food, clean water or climate regulation. Moreover, regime shift occurrence is expected to increase as human influence on the planet increases – the Anthropocene – including current trends on human induced climate change and biodiversity loss. When regime shifts are associated with a critical or bifurcation point, they may also be referred to as critical transitions.
The California sheephead is a species of wrasse native to the eastern Pacific Ocean. Its range is from Monterey Bay, California, to the Gulf of California, Mexico. It can live for up to 20 years in favorable conditions and can reach a size of up to 91 cm (3 ft) and a weight of 16 kg (35 lb). It is carnivorous, living in rocky reef and kelp bed habitats, feeding primarily on sea urchins, molluscs, and crustaceans.
Marine ecosystems are the largest of Earth's aquatic ecosystems and exist in waters that have a high salt content. These systems contrast with freshwater ecosystems, which have a lower salt content. Marine waters cover more than 70% of the surface of the Earth and account for more than 97% of Earth's water supply and 90% of habitable space on Earth. Seawater has an average salinity of 35 parts per thousand of water. Actual salinity varies among different marine ecosystems. Marine ecosystems can be divided into many zones depending upon water depth and shoreline features. The oceanic zone is the vast open part of the ocean where animals such as whales, sharks, and tuna live. The benthic zone consists of substrates below water where many invertebrates live. The intertidal zone is the area between high and low tides. Other near-shore (neritic) zones can include mudflats, seagrass meadows, mangroves, rocky intertidal systems, salt marshes, coral reefs, lagoons. In the deep water, hydrothermal vents may occur where chemosynthetic sulfur bacteria form the base of the food web.
An ecological cascade effect is a series of secondary extinctions that are triggered by the primary extinction of a key species in an ecosystem. Secondary extinctions are likely to occur when the threatened species are: dependent on a few specific food sources, mutualistic, or forced to coexist with an invasive species that is introduced to the ecosystem. Species introductions to a foreign ecosystem can often devastate entire communities, and even entire ecosystems. These exotic species monopolize the ecosystem's resources, and since they have no natural predators to decrease their growth, they are able to increase indefinitely. Olsen et al. showed that exotic species have caused lake and estuary ecosystems to go through cascade effects due to loss of algae, crayfish, mollusks, fish, amphibians, and birds. However, the principal cause of cascade effects is the loss of top predators as the key species. As a result of this loss, a dramatic increase of prey species occurs. The prey is then able to overexploit its own food resources, until the population numbers decrease in abundance, which can lead to extinction. When the prey's food resources disappear, they starve and may go extinct as well. If the prey species is herbivorous, then their initial release and exploitation of the plants may result in a loss of plant biodiversity in the area. If other organisms in the ecosystem also depend upon these plants as food resources, then these species may go extinct as well. An example of the cascade effect caused by the loss of a top predator is apparent in tropical forests. When hunters cause local extinctions of top predators, the predators' prey's population numbers increase, causing an overexploitation of a food resource and a cascade effect of species loss. Recent studies have been performed on approaches to mitigate extinction cascades in food-web networks.
Haliotis rufescens is a species of very large edible sea snail in the family Haliotidae, the abalone, ormers (British) or pāua. It is distributed from British Columbia, Canada, to Baja California, Mexico. It is most common in the southern half of its range.
This page is a list of fishing topics.
Overexploitation, also called overharvesting or ecological overshoot, refers to harvesting a renewable resource to the point of diminishing returns. Continued overexploitation can lead to the destruction of the resource, as it will be unable to replenish. The term applies to natural resources such as water aquifers, grazing pastures and forests, wild medicinal plants, fish stocks and other wildlife.
Enric Sala is a former university professor who saw himself writing the obituary of ocean life, and quit academia to become a full-time conservationist as a National Geographic Explorer-in-Residence. Sala’s present goals are to help protect critical marine ecosystems worldwide, and to develop new business models for marine conservation. He also produces documentary films and other media to raise awareness about the importance of a healthy environment, and to inspire country leaders to protect more of the natural world.
Fishing down the food web is the process whereby fisheries in a given ecosystem, "having depleted the large predatory fish on top of the food web, turn to increasingly smaller species, finally ending up with previously spurned small fish and invertebrates".
The following outline is provided as an overview of and topical guide to fisheries:
The Nereus Program is a global interdisciplinary initiative between the Nippon Foundation and the University of British Columbia that was created to further our knowledge of how best to attain sustainability for our world’s oceans. In addition to the Nippon Foundation and UBC, the program partners with University of Cambridge, Duke University, Princeton University, Stockholm University, United Nations Environment Program-World Conservation Monitoring Centre and Utrecht University. The program is built around three core objectives: to conduct collaborative ocean research across the natural and social sciences, to develop an interdisciplinary network of experts that can engage in discussion of complex and multifaceted questions of ocean sustainability, and to transfer these ideas to practical solutions in global policy forums.
Seriola dorsalis, the California yellowtail is a species of ray-finned fish of the family Carangidae. This species is also known by several alternate names, such as yellowtail jack amberjack, forktail, mossback, white salmon and yellowtail tunis or tuna or by its Spanish name jurel. Although previously thought to belong to S. lalandi, recent genetic analysis distinguished California yellowtail as a distinct species from the yellowtail amberjack. The California yellowtail is differentiated from yellowtail amberjack as they differ in range. The yellowtail amberjack is found farther south in the Pacific Ocean.
Human activities affect marine life and marine habitats through overfishing, habitat loss, the introduction of invasive species, ocean pollution, ocean acidification and ocean warming. These impact marine ecosystems and food webs and may result in consequences as yet unrecognised for the biodiversity and continuation of marine life forms.
A Science on the Scales: The Rise of Canadian Atlantic Fisheries Biology, 1898-1939 is a 2011 book by Jennifer Hubbard. The book provides an analysis of Canadian fisheries history with the tools of the professional historian, when most earlier works on the topic came from fisheries scientists themselves.
A marine coastal ecosystem is a marine ecosystem which occurs where the land meets the ocean. Worldwide there is about 620,000 kilometres (390,000 mi) of coastline. Coastal habitats extend to the margins of the continental shelves, occupying about 7 percent of the ocean surface area. Marine coastal ecosystems include many very different types of marine habitats, each with their own characteristics and species composition. They are characterized by high levels of biodiversity and productivity.
Volume 22, No.3, 2006