145
gyre
growth overfishing situation at which a population is exploited beyond the F max
(~fishing mortality rate) level at which it would give the maximum sustainable yield
for the given mesh size and exploitation pattern.
growth rate in organisms the average increase of weight per unit of time. In populations the number of organisms added to the population per unit of time.
The specific growth rate of a population is the growth rate divided by the
number of organisms initially present or by the average number of organisms during the period of time.
guano dried sea-bird excreta (a mixture of urine and feces), piled up at undisturbed and densely packed seabird colonies on arid, subtropical islands.
Guano islands are typically situated in highly productive upwelling areas
which support massive food-stocks and huge colonies of seabirds. Guanoproducing seabirds often withhold their excreta for nest building. A Guanay
cormorant (Phalacrocorax bougainvillii) deposits a minimum of 1 kg dry
guano on land each month. From the 19th century onward, guano has been
commercially exploited as an inexpensive fertilizer that is rich in nitrogen,
phosphate and calcium. Whole seabird colonies have been destroyed
through reckless exploitation of the resource (including the birds themselves). Between 1848 and 1875 more than 20 million tons of guano were
exported to Europe and the USA from Peruvian deposits. Today, guano is
harvested as a renewable resource, that accumulates at about 8 cm per year.
The main birds involved are cormorants, gannets and boobies, pelicans, and
penguins.
Gulf Stream strong boundary current along the east coast of N. America, carrying
water from the Gulf of Mexico northeastward. The name Gulf Stream is usually reserved for the part of the current that has the typical character of a
strong boundary current and the continuation to the east of New Foundland
is better indicated by North Atlantic Current, which splits into different
branches. Part of it is returned and forms the North Atlantic gyre, part of it
feeds the Norwegian and other arctic seas.
gut content the amount of food present in the alimentary tract, expressed in
terms of weight (mostly ash-free dry weight), or numbers of different food
items. A difficulty is the variable degree of digestion; sometimes different
digestive stages are defined for separate determination of numbers or
weights.
guyot ~tablemount.
gyre a closed current system of ocean-wide dimensions. A typical subtropical
ocean gyre consists of a strong boundary current at the western branch that car-
gyre
growth overfishing situation at which a population is exploited beyond the F max
(~fishing mortality rate) level at which it would give the maximum sustainable yield
for the given mesh size and exploitation pattern.
growth rate in organisms the average increase of weight per unit of time. In populations the number of organisms added to the population per unit of time.
The specific growth rate of a population is the growth rate divided by the
number of organisms initially present or by the average number of organisms during the period of time.
guano dried sea-bird excreta (a mixture of urine and feces), piled up at undisturbed and densely packed seabird colonies on arid, subtropical islands.
Guano islands are typically situated in highly productive upwelling areas
which support massive food-stocks and huge colonies of seabirds. Guanoproducing seabirds often withhold their excreta for nest building. A Guanay
cormorant (Phalacrocorax bougainvillii) deposits a minimum of 1 kg dry
guano on land each month. From the 19th century onward, guano has been
commercially exploited as an inexpensive fertilizer that is rich in nitrogen,
phosphate and calcium. Whole seabird colonies have been destroyed
through reckless exploitation of the resource (including the birds themselves). Between 1848 and 1875 more than 20 million tons of guano were
exported to Europe and the USA from Peruvian deposits. Today, guano is
harvested as a renewable resource, that accumulates at about 8 cm per year.
The main birds involved are cormorants, gannets and boobies, pelicans, and
penguins.
Gulf Stream strong boundary current along the east coast of N. America, carrying
water from the Gulf of Mexico northeastward. The name Gulf Stream is usually reserved for the part of the current that has the typical character of a
strong boundary current and the continuation to the east of New Foundland
is better indicated by North Atlantic Current, which splits into different
branches. Part of it is returned and forms the North Atlantic gyre, part of it
feeds the Norwegian and other arctic seas.
gut content the amount of food present in the alimentary tract, expressed in
terms of weight (mostly ash-free dry weight), or numbers of different food
items. A difficulty is the variable degree of digestion; sometimes different
digestive stages are defined for separate determination of numbers or
weights.
guyot ~tablemount.
gyre a closed current system of ocean-wide dimensions. A typical subtropical
ocean gyre consists of a strong boundary current at the western branch that car-