External links
- Dr Villy Christensen UBC web site.
- Animated documentary on Chesapeake Bay NOAA.
| Authority control databases: Academics |
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Villy Christensen | |
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| Alma mater | Copenhagen University |
| Known for | Developing Ecopath |
| Scientific career | |
| Fields | Ecosystem modelling, fisheries science |
| Institutions | UBC Fisheries Centre, University of British Columbia |
| Doctoral advisor | Sven Erik Jørgensen |
Villy Christensen is an ecosystem modeller with a background in fisheries science. He is known for his work as a project leader and core developer of Ecopath, an ecosystem modelling software system widely used in fisheries management. [1] Ecopath was initially an initiative of the NOAA, but since primarily developed at the UBC Fisheries Centre of the University of British Columbia. In 2007, it was named as one of the ten biggest scientific breakthroughs in NOAA's 200-year history. The citation states that Ecopath "revolutionized scientists' ability worldwide to understand complex marine ecosystems". [2]
Christensen did his Ph.D. under Sven Erik Jørgensen at Copenhagen University. Jeffrey Polovina initiated the Ecopath approach in the early 1980s. [3] Christensen, along with Daniel Pauly and others, has been involved in the subsequent development of Ecopath since 1990. [4] [5]
Christensen currently facilitates international workshops on Ecopath around the world. He is a professor at the UBC Fisheries Centre at the University of British Columbia, specialising in ecosystem modelling. His main project is with the Sea Around Us Project working on "database-driven ecosystem model construction", with the aim of using "global, spatial databases to parameterize, balance and fit ecosystem models". [6] This work includes developing a dynamic exchange model of biomass over time in the Chesapeake Bay area, as well as how marine protected areas can be optimally positioned. [6] He is also director of the Lenfest Ocean Futures Project, [7] where a visualization system is being developed to support decision making in ecosystem-based fisheries management. This system combines Blender, a 3D-gaming engine, with Ecopath. [8] [9] [10] [11]
| Authority control databases: Academics |
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FishBase is a global species database of fish species. It is the largest and most extensively accessed online database on adult finfish on the web. Over time it has "evolved into a dynamic and versatile ecological tool" that is widely cited in scholarly publications.
Overfishing is the removal of a species of fish from a body of water at a rate greater than that the species can replenish its population naturally, resulting in the species becoming increasingly underpopulated in that area. Overfishing can occur in water bodies of any sizes, such as ponds, wetlands, rivers, lakes or oceans, and can result in resource depletion, reduced biological growth rates and low biomass levels. Sustained overfishing can lead to critical depensation, where the fish population is no longer able to sustain itself. Some forms of overfishing, such as the overfishing of sharks, has led to the upset of entire marine ecosystems. Types of overfishing include growth overfishing, recruitment overfishing, and ecosystem overfishing.
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.
The goal of fisheries management is to produce sustainable biological, environmental and socioeconomic benefits from renewable aquatic resources. Wild fisheries are classified as renewable when the organisms of interest produce an annual biological surplus that with judicious management can be harvested without reducing future productivity. Fishery management employs activities that protect fishery resources so sustainable exploitation is possible, drawing on fisheries science and possibly including the precautionary principle.
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.
The Sea Around Us is an international research initiative and a member of the Global Fisheries Cluster at the University of British Columbia. The Sea Around Us assesses the impact of fisheries on the marine ecosystems of the world and offers mitigating solutions to a range of stakeholders. To achieve this, the Sea Around Us presents fisheries and fisheries-related data at spatial scales that have ecological and policy relevance, such as by Exclusive Economic Zones, High Seas areas, Large Marine Ecosystems and Ecosystems.
An ecosystem model is an abstract, usually mathematical, representation of an ecological system, which is studied to better understand the real system.
CalCOFI is a multi-agency partnership formed in 1949 to investigate the collapse of the sardine population off California. The organization's members are from NOAA Fisheries Service, Scripps Institution of Oceanography, and California Department of Fish and Wildlife. The scope of this research has evolved into the study of marine ecosystems off California and the management of its fisheries resources. In 2004, the CalCOFI survey area became one of 26 Long Term Ecological Research Network (LTER) research sites. This time-series of oceanographic and fisheries data allows scientists to assess the human impact and effects of climate change on the coastal ocean ecosystem. CalCOFI hydrographic and biological data, publications, and web information are distributed for use without restriction under the terms of the GNU Free Documentation License.
The trophic level of an organism is the position it occupies in a food web. Within a food web, a food chain is a succession of organisms that eat other organisms and may, in turn, be eaten themselves. The trophic level of an organism is the number of steps it is from the start of the chain. A food web starts at trophic level 1 with primary producers such as plants, can move to herbivores at level 2, carnivores at level 3 or higher, and typically finish with apex predators at level 4 or 5. The path along the chain can form either a one-way flow or a part of a wider food "web". Ecological communities with higher biodiversity form more complex trophic paths.
Ecopath with Ecosim (EwE) is a free and open source ecosystem modelling software suite, initially started at NOAA by Jeffrey Polovina, but has since primarily been developed at the formerly UBC Fisheries Centre of the University of British Columbia. In 2007, it was named as one of the ten biggest scientific breakthroughs in NOAA's 200-year history. The NOAA citation states that Ecopath "revolutionized scientists' ability worldwide to understand complex marine ecosystems". Behind this lie more than three decades of development work in association with a thriving network of fisheries scientists such as Villy Christensen, Carl Walters and Daniel Pauly, and software engineers around the world. EwE is funded through projects, user contributions, user support, training courses and co-development collaborations. Per November 2021 there are an estimated 8000+ users across academia, non-government organizations, industry and governments in 150+ countries.
Forage fish, also called prey fish or bait fish, are small pelagic fish that feed on planktons and other small aquatic organisms. They are in turn preyed upon by various predators including larger fish, seabirds and marine mammals, this making them keystone species in their aquatic ecosystems.
Carl Walters is an American-born Canadian biologist known for his work involving fisheries stock assessments, the adaptive management concept, and ecosystem modeling. Walters has been a professor of Zoology and Fisheries at the University of British Columbia since 1969. He is one of the main developers of the ecological modelling software Ecopath. His most recent work focuses on how to adjust human behaviors in environments that are full of uncertainty. He is a recent recipient of the Volvo Environment Prize (2006). In 2019, Dr. Walters became a Member of the Order of British Columbia.
Ussif Rashid Sumaila is a professor of ocean and fisheries economics at the University of British Columbia, Canada, and the Director of the Fisheries Economics Research Unit at the UBC Institute for the Oceans and Fisheries. He is also appointed with the UBC School of Public Policy and Global Affairs. He specializes in bioeconomics, marine ecosystem valuation and the analysis of global issues such as fisheries subsidies, IUU fishing and the economics of high and deep seas fisheries. Sumaila has experience working in fisheries and natural resource projects in Norway, Canada and the North Atlantic region, Namibia and the Southern African region, Ghana and the West African region and Hong Kong and the South China Sea. He received his Bachelor of Science degree with honours from Ahmadu Bello University University in Nigeria and received his PhD from Bergen University in Norway.
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".
SeaLifeBase is a global online database of information about marine life. It aims to provide key information on the taxonomy, distribution and ecology of all marine species in the world apart from finfish. SeaLifeBase is in partnership with the WorldFish Center in Malaysia and the UBC Institute for the Oceans and Fisheries at the University of British Columbia. Daniel Pauly is the principal investigator and it is coordinated by Maria Lourdes D. Palomares. As of March 2023, it included descriptions of 85,000 species, 59,400 common names, 15,500 pictures, and references to 39,300 works in the scientific literature. SeaLifeBase complements FishBase, which provides parallel information for finfish.
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.
William Cheung is a marine biologist, well known for his research on the impacts of climate change on marine ecosystems and fisheries. He currently works as director of science of the Nereus Program and is also an associate professor at the University of British Columbia, as well as Leader at the UBC Changing Ocean Research Unit.
Jeffrey Polovina is an American marine scientist. He is known for creating the marine ecosystem model Ecopath.
The Fisheries and Marine Ecosystem Model Intercomparison Project (Fish-MIP) is a marine biology project to compare computer models of the impact of climate change on sea life. Founded in 2013 as part of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP), it was established to answer questions about the future of marine biodiversity, seafood supply, fisheries, and marine ecosystem functioning in the context of various climate change scenarios. It combines diverse marine ecosystem models from both the global and regional scale through a standardized protocol for ensemble modelling in an attempt to correct for any bias in the individual models that make up the ensemble. Fish-MIP's goal is to use this ensemble modelling to project a more robust picture of the future state of fisheries and marine ecosystems under the impacts of climate change, and ultimately to help inform fishing policy.
