178
Indonesia occasionally entire coral islands and
reefs were mined for cement production.
While much evidence was found that corals
may be destroyed by a wide range of anthropogenic effects, certain scientists consider two factors dominant: acidification and global warming
of seawater (Hoegh-Guldberg et al. 2017). In fact
25% of marine species live in the area of coral
reefs and 75% of coral reefs are endangered
(Burke et al. 2011).
Unfortunately not only life on coral reefs is in
danger. Global overfishing makes its influence
felt owing to large-scale fishing fleets.
Occasionally in certain places arguments and
debates between certain fishing nations almost
end in fights due to the permitted amount to be
fished. In marine fishing humanity has to face
with the fact that the resources of Earth are finite.
Furthermore, ecological law has to be accepted
and put in front of economic interests, otherwise
the long-term goals of humanity will be risked.
Let us see what overfishing means. A population of fish grows by progeny in natural conditions while it decreases as a result of natural
mortality (disease, age, predators) (Fig. 4.72). If
marine conditions are beneficial progeny exceeds
natural mortality and the population will grow
(Fig. 4.72a). In such cases fishing may sustain the
balance stock without any harmful consequences,
i.e. the fished amount is supplied from year to
year (Fig. 4.72b).
In a healthy fish population bigger, older fish
are found in higher ratio. When fishing is started
catchment will be rich, many large fish will be in
the net. Expanding fishing, however, reduces the
stock and also the number of natural mortality.
Fishing quota can be given only for the given
stock with which balance still develops between
natural progeny and mortality + fished amount. If
catchment is greater than natural supply, the stock
will decrease (Fig. 4.72c) resulting in overfishing.
Maximum sustainable yield can be realised in
the case of moderate fishing. Considering the
population the best thing to do is fishing all sizes
of fish in more or less similar rates (for this different mesh sizes are required) because in this
way the age structure of the population remains
healthy.
Unfortunately this ecologically acceptable
and sustainable fishing method is not kept—due
to the lack of adequate cooperation—by fishing
nations. The result is presented in Fig. 4.73. By
the end of the twentieth century the size of areas
of the world ocean suitable for fishing and utilised completely decreased to 40%, the rest has
been either overfished or collapsed. The latter
means that catchment worth the work cannot be
expected in those areas, thus the ecological loss
also appears as economic loss.
Figure 4.74 presents the regional differences
of the intensity of industrial fishing catch.
Intensive industrial fishing was going on along
the shores of developed nearshore countries
already in the 1950s. This expanded both in space
and intensity by the 2000s. Greatest change
occurred along the shores of Southeast and South
Asia. The second spectacular change occurred in
more distant marine areas where the intensity of
fishing catch increased significantly.
Considering the decline of species an important feature of industrial fishing has to be mentioned. This is unintentional (additional,
secondary) fishing. Several tonnes of fish are
uplifted onto the shipboard by machines in the
course of which a significant portion of the fish in
the net dies due to great pressure. Refuse fish
(undersized fish or species for the fishing of which
fishermen have no permit) are returned into the
sea dead or almost dead. Not only fish end up in
the net but marine mammals, and turtles as well,
most of which cannot survive the sufferings.
According to estimates, this destruction constitutes one-third of the total marine catch.
Whaling has to be mentioned separately as the
industry grew so much by the middle of the twentieth century that several whale species were
threatened by extinction, among them, the largest
blue whale (Balaenoptera musculus) as well.
Therefore in 1946 the International Whaling
Commission (IWC) was founded. The global
intergovernmental
body
established
the
International Convention for the Regulation of
Whaling (ICRW). IWC has made the regulation
of whaling stricter since its foundation.
Moratorium on commercial whaling was
announced in 1982. Initially ships hunting and
4 Changes on Earth as a Result of Interaction Between the Society and Nature
Indonesia occasionally entire coral islands and
reefs were mined for cement production.
While much evidence was found that corals
may be destroyed by a wide range of anthropogenic effects, certain scientists consider two factors dominant: acidification and global warming
of seawater (Hoegh-Guldberg et al. 2017). In fact
25% of marine species live in the area of coral
reefs and 75% of coral reefs are endangered
(Burke et al. 2011).
Unfortunately not only life on coral reefs is in
danger. Global overfishing makes its influence
felt owing to large-scale fishing fleets.
Occasionally in certain places arguments and
debates between certain fishing nations almost
end in fights due to the permitted amount to be
fished. In marine fishing humanity has to face
with the fact that the resources of Earth are finite.
Furthermore, ecological law has to be accepted
and put in front of economic interests, otherwise
the long-term goals of humanity will be risked.
Let us see what overfishing means. A population of fish grows by progeny in natural conditions while it decreases as a result of natural
mortality (disease, age, predators) (Fig. 4.72). If
marine conditions are beneficial progeny exceeds
natural mortality and the population will grow
(Fig. 4.72a). In such cases fishing may sustain the
balance stock without any harmful consequences,
i.e. the fished amount is supplied from year to
year (Fig. 4.72b).
In a healthy fish population bigger, older fish
are found in higher ratio. When fishing is started
catchment will be rich, many large fish will be in
the net. Expanding fishing, however, reduces the
stock and also the number of natural mortality.
Fishing quota can be given only for the given
stock with which balance still develops between
natural progeny and mortality + fished amount. If
catchment is greater than natural supply, the stock
will decrease (Fig. 4.72c) resulting in overfishing.
Maximum sustainable yield can be realised in
the case of moderate fishing. Considering the
population the best thing to do is fishing all sizes
of fish in more or less similar rates (for this different mesh sizes are required) because in this
way the age structure of the population remains
healthy.
Unfortunately this ecologically acceptable
and sustainable fishing method is not kept—due
to the lack of adequate cooperation—by fishing
nations. The result is presented in Fig. 4.73. By
the end of the twentieth century the size of areas
of the world ocean suitable for fishing and utilised completely decreased to 40%, the rest has
been either overfished or collapsed. The latter
means that catchment worth the work cannot be
expected in those areas, thus the ecological loss
also appears as economic loss.
Figure 4.74 presents the regional differences
of the intensity of industrial fishing catch.
Intensive industrial fishing was going on along
the shores of developed nearshore countries
already in the 1950s. This expanded both in space
and intensity by the 2000s. Greatest change
occurred along the shores of Southeast and South
Asia. The second spectacular change occurred in
more distant marine areas where the intensity of
fishing catch increased significantly.
Considering the decline of species an important feature of industrial fishing has to be mentioned. This is unintentional (additional,
secondary) fishing. Several tonnes of fish are
uplifted onto the shipboard by machines in the
course of which a significant portion of the fish in
the net dies due to great pressure. Refuse fish
(undersized fish or species for the fishing of which
fishermen have no permit) are returned into the
sea dead or almost dead. Not only fish end up in
the net but marine mammals, and turtles as well,
most of which cannot survive the sufferings.
According to estimates, this destruction constitutes one-third of the total marine catch.
Whaling has to be mentioned separately as the
industry grew so much by the middle of the twentieth century that several whale species were
threatened by extinction, among them, the largest
blue whale (Balaenoptera musculus) as well.
Therefore in 1946 the International Whaling
Commission (IWC) was founded. The global
intergovernmental
body
established
the
International Convention for the Regulation of
Whaling (ICRW). IWC has made the regulation
of whaling stricter since its foundation.
Moratorium on commercial whaling was
announced in 1982. Initially ships hunting and
4 Changes on Earth as a Result of Interaction Between the Society and Nature