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International Journal of Marine Science 2013, Vol.3, No.28, 219-224
http://ijms.sophiapublisher.com
222
dumped into the pond. This sparked a negative impact,
especially in gastropods and crustaceans. It seems to
be obvious that environmental modifications (natural
and anthropogenic)
caused such ichthyofauna’s
changes. Indeed the trophic chain is now in danger.
The sustainability of the lagoon environment can
become impossible.
We must appeal to the good sense and strike a balance
between the human current
modus vivendi
and the
preservation of endangered species.
If the environmental awareness is something quite
recent that only in the second half of the 20th century
began to be an object of study, the result of a profound
change that humanity operated in the ecosystems
through the rampant use of new technologies, find the
middle ground, the fair procedure between profit and
preservation of species has been one of the greatest
challenges that came up to our 21
st
century and which
will continue to be for decades a key theme for the
various quarters of civil society.
Hence the importance of interdisciplinary dialogue
that should not be a mere casual meeting among
academics, but it should be a continuum, a permanent
dialogue discussion and improvement.
3 Discussion
Through the analysis of this historical sources stored
in the National Archive of Portugal (DGARQ-Torre
do Tombo) we were able to detect important physical
and human components. From a physical point of
view, the collected information contains two major
coordinates: the sea and the river.
Since ancient times the lagoon of Aveiro was occupied
and exploited by Man (Bastos, 2006). This has
contributed to the change of its configuration and
modification of environmental characteristics (Figure 3).
The transformation of the coastal stretch and the
strong anthropic action (especially from the
mid-twentieth century) led to the destabilization of the
animal ecosystem.
For example refer to part for Ovar, which states that in
1758 this lagoon passage “raise fish, abundantly
European eel, mullets (
Mugil cephalus
), plaice, and
less abundant snook (
Centropomus undecimalus
)
,
lamprey, shad and croakers (
Micropogonius undulates
).”
(Torre do Tombo on line PT-TT-Mprq/26/45).
Even in the second half of the 18th century, as testify
Figure 3 The evolution of Aveiro’s lagoon
the Parish Description of Aveiro, the people could
enjoy plenty species such as eels. With the entrance in
the 20
th
century and with the implementation of
industries in the area significant changes were
observed.
From the 30's, with the proliferation of heavy
chemical industry in Estarreja (City of Aveiro region),
the negative impact of contamination of the lagoon's
fauna and flora are reflections of serious environmental
effect of imbalance of human action and dramatic
contours took on some of the species of yore.
One of the many indicators of this strong
contamination is expressed by the accumulation of
heavy metals in eels,
ex-libris
the region of Aveiro, as
are highly appreciated of the gastronomic point of
view and are very significant economic resources
(Eira
et al
., 2009).
The relevance of the information gathered leads us to
the question of the species identified in 1758 (Figure 4)
which ceased to be referred to in later documentation?
The analysis is evident: shads, trouts, European eel
and lampreys are no longer referred to. Why are they
no longer mentioned?
Firstly it is important to know if those species are
present nowadays. The characterization of the
ichthyofauna of Ria de Aveiro has been subject of
several publications in the last years (Garnerot
et al
.,
2004; Jemuce, 2008; Macaringue, 2009; Pinto, 2009).