Milner Baily Schaefer
Encyclopedia
Milner Baily Schaefer was born in Cheyenne, Wyoming
, in 1912 and died at the age of 57 in San Diego, California
in 1970. He is notable for his work on the population dynamics
of fisheries.
Schaefer worked as a biologist at the Washington State Fisheries Department and from 1937-1942 as a scientist for the International Pacific Salmon Fisheries Commission in New Westminster
, British Columbia
, Canada
. In 1946 he joined the United States Fish and Wildlife Service
and held various posts at the Fishery Biology Headquarters at Stanford University
. Later, he worked at the Pacific Oceanic Fisheries Investigations Laboratory in Honolulu, Hawaii
and completed a doctorate in fisheries from the University of Washington
in 1950. In 1951 Schaefer became Director of Investigations at the Inter-American Tropical Tuna Commission
(IATTC). IATTC established its first headquarters at the Scripps Institution of Oceanography
.
and published a fishery equilibrium model based on the Verhulst
population growth model and an assumption of a bi-linear catch equation, often referred to as the Schaefer short-term catch equation:
where the variables are; H, referring to catch (harvest) over a given period of time (e.g. a year); E, the fishing effort over the given period; X, the fish stock biomass at the beginning of the period (or the average biomass), and the parameter q represents the catchability of the stock. Assuming the catch to equal the net natural growth in the population over the same period (
), the equilibrium catch is a function of the long term fishing effort E:
r and K being biological parameters representing intrinsic growth rate and natural equilibrium biomass respectively.
Schaefer published during the 1950s a range of papers of empirical studies based on the model. Other researchers also soon saw the potential of developing the model tools further into bioeconomic
studies.
Cheyenne, Wyoming
Cheyenne is the capital and most populous city of the U.S. state of Wyoming and the county seat of Laramie County. It is the principal city of the Cheyenne, Wyoming, Metropolitan Statistical Area which encompasses all of Laramie County. The population is 59,466 at the 2010 census. Cheyenne is the...
, in 1912 and died at the age of 57 in San Diego, California
San Diego, California
San Diego is the eighth-largest city in the United States and second-largest city in California. The city is located on the coast of the Pacific Ocean in Southern California, immediately adjacent to the Mexican border. The birthplace of California, San Diego is known for its mild year-round...
in 1970. He is notable for his work on the population dynamics
Population dynamics of fisheries
A fishery is an area with an associated fish or aquatic population which is harvested for its commercial or recreational value. Fisheries can be wild or farmed. Population dynamics describes the ways in which a given population grows and shrinks over time, as controlled by birth, death, and...
of fisheries.
Schaefer worked as a biologist at the Washington State Fisheries Department and from 1937-1942 as a scientist for the International Pacific Salmon Fisheries Commission in New Westminster
New Westminster, British Columbia
New Westminster is an historically important city in the Lower Mainland region of British Columbia, Canada, and is a member municipality of the Greater Vancouver Regional District. It was founded as the capital of the Colony of British Columbia ....
, British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
. In 1946 he joined the United States Fish and Wildlife Service
United States Fish and Wildlife Service
The United States Fish and Wildlife Service is a federal government agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats...
and held various posts at the Fishery Biology Headquarters at Stanford University
Stanford University
The Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private research university on an campus located near Palo Alto, California. It is situated in the northwestern Santa Clara Valley on the San Francisco Peninsula, approximately northwest of San...
. Later, he worked at the Pacific Oceanic Fisheries Investigations Laboratory in Honolulu, Hawaii
Honolulu, Hawaii
Honolulu is the capital and the most populous city of the U.S. state of Hawaii. Honolulu is the southernmost major U.S. city. Although the name "Honolulu" refers to the urban area on the southeastern shore of the island of Oahu, the city and county government are consolidated as the City and...
and completed a doctorate in fisheries from the University of Washington
University of Washington
University of Washington is a public research university, founded in 1861 in Seattle, Washington, United States. The UW is the largest university in the Northwest and the oldest public university on the West Coast. The university has three campuses, with its largest campus in the University...
in 1950. In 1951 Schaefer became Director of Investigations at the Inter-American Tropical Tuna Commission
Inter-American Tropical Tuna Commission
The Inter-American Tropical Tuna Commission is an international commission that is responsible for the conservation and management of tuna and other marine resources in the eastern Pacific Ocean.-History:The Inter-American Tropical Tuna Commission was created by the Convention for the...
(IATTC). IATTC established its first headquarters at the Scripps Institution of Oceanography
Scripps Institution of Oceanography
Scripps Institution of Oceanography in La Jolla, California, is one of the oldest and largest centers for ocean and earth science research, graduate training, and public service in the world...
.
Schaefer short-term catch equation
During his period at the IATTC, Schaefer worked on the development of theories of fishery dynamicsPopulation dynamics of fisheries
A fishery is an area with an associated fish or aquatic population which is harvested for its commercial or recreational value. Fisheries can be wild or farmed. Population dynamics describes the ways in which a given population grows and shrinks over time, as controlled by birth, death, and...
and published a fishery equilibrium model based on the Verhulst
Pierre François Verhulst
Pierre François Verhulst was a mathematician and a doctor in number theory from the University of Ghent in 1825...
population growth model and an assumption of a bi-linear catch equation, often referred to as the Schaefer short-term catch equation:
where the variables are; H, referring to catch (harvest) over a given period of time (e.g. a year); E, the fishing effort over the given period; X, the fish stock biomass at the beginning of the period (or the average biomass), and the parameter q represents the catchability of the stock. Assuming the catch to equal the net natural growth in the population over the same period (
), the equilibrium catch is a function of the long term fishing effort E:r and K being biological parameters representing intrinsic growth rate and natural equilibrium biomass respectively.
Schaefer published during the 1950s a range of papers of empirical studies based on the model. Other researchers also soon saw the potential of developing the model tools further into bioeconomic
Bioeconomics
Bioeconomics is closely related to the early development of theories in fisheries economics, initially in the mid 1950s by Canadian economists Scott Gordon and Anthony Scott...
studies.