104
Chapter 7: Provinces: The Secondary Compartments
compartments, we must expect to have insufficient numbers in each to judge whether
the characteristics of adjacent compartments are significantly different, and therefore if
the boundaries between them are real.
Obviously, the idea of partitioning the ocean into provinces is not new, and many
schemes to do this already exist beyond those from strictly descriptive study of the
geographical distribution of biota discussed in Chapter 2. Why, you might ask, do we
need yet another scheme? This is not the place to review the validity for our purpose
of existing schemes, such as the Large Marine Ecosystem concept introduced for fishery
management purposes by Ken Sherman that—as I have suggested elsewhere—is perhaps
principally useful as a symbol and rallying point for funds for research on “ecosystemsensitive” fisheries management. The compartments of this scheme, as of other such
schemes, have only a limited basis in regional oceanography. Consider the partitioning
of global fishery statistics among subareas of the ocean by the United Nations Food and
Agricultural Organisation (FAO) for the past many decades. These compartments have
been discussed (Gulland, 1971) as if they represented natural areas of the ocean, though
a glance at the FAO map will show that they conform to no possible oceanographic
reality. One of the most extreme examples is FAO area “H2,” which runs from the Bay
of Bengal to Tasmania and includes the whole eastern part of the Indian Ocean. To put
a part of the Southern Ocean together with the Bay of Bengal for fishery purposes is a
breathtaking denial of the natural order of the ocean and also (dare I say?) of political
reality.
All this suggests that biological oceanographers face the same difficulty as did Tomczak
and Godfrey (1994), who commented that previous regional systems fail to match our
present understanding of ocean circulation. They pointed out that the widely used subdivision of the ocean basins adopted by the International Hydrographic Bureau (IHB) is
not optimal for scientific description of natural processes. The IHB map assumes that the
Atlantic, Pacific, and Indian oceans extend poleward down to Antarctica and was drafted
before the true nature of the circulation of the Southern Ocean was understood. In fact,
the polar ocean is a good starting point to introduce the present suggestion for a system
of oceanic biogeographic provinces.
Since the days of the seminal investigations of Alister Hardy and his colleagues in the
Discovery expeditions to the Southern Ocean during the 1920s, oceanographers, including
biologists, have found overwhelming evidence for the ecological, chemical, and physical
unity of the Southern Ocean. This ocean is unique because of the annular currents
that flow continuously around the globe and because of the importance of convergence
and divergence within these flows. Therefore, contrary to the view of the International
Hydrographic Bureau, an oceanographer must place the southern boundaries of the
three principal oceans—Atlantic, Pacific, and Indian—at the Subtropical Front. This lies
between Patagonia and Tasmania and just to the south of Australia and South Africa.
Further poleward is the Southern Ocean.
In the other hemisphere, the Arctic Ocean must be treated differently. This is a
relatively small basin, almost land-locked and with narrow connections to the Atlantic
and Pacific Oceans, and is almost perpetually ice-covered, except marginally along the
Asiatic coast. It will be appropriate to follow the physical oceanographers and treat this
as a land-locked sea such as the Baltic, Mediterranean, Caribbean, Okhotsk, and Red
Seas. Such seas could either be discussed collectively or allocated to the adjoining ocean
as a more-or-less open “marginal sea.” The latter option is greatly more informative and
will be followed. The Arctic shall be considered a marginal sea of the Atlantic, to which
it is connected through Fram Straits and the Norwegian-Greenland Sea. Tomczak and
Goodall consider the Arctic Ocean, the Barents Sea, and the Norwegian-Greenland Sea to
be a useful unit (the “Arctic Mediterranean Sea”) when describing regional circulation,
but we shall find it more useful to treat them separately.
Chapter 7: Provinces: The Secondary Compartments
compartments, we must expect to have insufficient numbers in each to judge whether
the characteristics of adjacent compartments are significantly different, and therefore if
the boundaries between them are real.
Obviously, the idea of partitioning the ocean into provinces is not new, and many
schemes to do this already exist beyond those from strictly descriptive study of the
geographical distribution of biota discussed in Chapter 2. Why, you might ask, do we
need yet another scheme? This is not the place to review the validity for our purpose
of existing schemes, such as the Large Marine Ecosystem concept introduced for fishery
management purposes by Ken Sherman that—as I have suggested elsewhere—is perhaps
principally useful as a symbol and rallying point for funds for research on “ecosystemsensitive” fisheries management. The compartments of this scheme, as of other such
schemes, have only a limited basis in regional oceanography. Consider the partitioning
of global fishery statistics among subareas of the ocean by the United Nations Food and
Agricultural Organisation (FAO) for the past many decades. These compartments have
been discussed (Gulland, 1971) as if they represented natural areas of the ocean, though
a glance at the FAO map will show that they conform to no possible oceanographic
reality. One of the most extreme examples is FAO area “H2,” which runs from the Bay
of Bengal to Tasmania and includes the whole eastern part of the Indian Ocean. To put
a part of the Southern Ocean together with the Bay of Bengal for fishery purposes is a
breathtaking denial of the natural order of the ocean and also (dare I say?) of political
reality.
All this suggests that biological oceanographers face the same difficulty as did Tomczak
and Godfrey (1994), who commented that previous regional systems fail to match our
present understanding of ocean circulation. They pointed out that the widely used subdivision of the ocean basins adopted by the International Hydrographic Bureau (IHB) is
not optimal for scientific description of natural processes. The IHB map assumes that the
Atlantic, Pacific, and Indian oceans extend poleward down to Antarctica and was drafted
before the true nature of the circulation of the Southern Ocean was understood. In fact,
the polar ocean is a good starting point to introduce the present suggestion for a system
of oceanic biogeographic provinces.
Since the days of the seminal investigations of Alister Hardy and his colleagues in the
Discovery expeditions to the Southern Ocean during the 1920s, oceanographers, including
biologists, have found overwhelming evidence for the ecological, chemical, and physical
unity of the Southern Ocean. This ocean is unique because of the annular currents
that flow continuously around the globe and because of the importance of convergence
and divergence within these flows. Therefore, contrary to the view of the International
Hydrographic Bureau, an oceanographer must place the southern boundaries of the
three principal oceans—Atlantic, Pacific, and Indian—at the Subtropical Front. This lies
between Patagonia and Tasmania and just to the south of Australia and South Africa.
Further poleward is the Southern Ocean.
In the other hemisphere, the Arctic Ocean must be treated differently. This is a
relatively small basin, almost land-locked and with narrow connections to the Atlantic
and Pacific Oceans, and is almost perpetually ice-covered, except marginally along the
Asiatic coast. It will be appropriate to follow the physical oceanographers and treat this
as a land-locked sea such as the Baltic, Mediterranean, Caribbean, Okhotsk, and Red
Seas. Such seas could either be discussed collectively or allocated to the adjoining ocean
as a more-or-less open “marginal sea.” The latter option is greatly more informative and
will be followed. The Arctic shall be considered a marginal sea of the Atlantic, to which
it is connected through Fram Straits and the Norwegian-Greenland Sea. Tomczak and
Goodall consider the Arctic Ocean, the Barents Sea, and the Norwegian-Greenland Sea to
be a useful unit (the “Arctic Mediterranean Sea”) when describing regional circulation,
but we shall find it more useful to treat them separately.