In monthly biological samples of M. amazonicum in Guajará Bay and Mosqueiro
island, were studied reproduction, density, morphometric relationships and
population dynamics. Two other sample designs was realized in two perennial
the same estuary. Results indicate differences in capture of this species using
different bait of meal, but is solely on the abundance and population structure
does not change. The species is most abundant in the dry season, supporting
the idea higher catchability of fishery resources. In Combu island was found
species with larger sizes. Females are significantly larger and heavier than
males, indicating the differentiation in metabolism due to reproduction. Sex ratio
of males is higher in smaller size classes, which may indicate an increase in
predation on smaller sizes of males due to their behavior more aggressive than
the females or males simply because they reach lengths larger than females
are more heavily preyed upon by fishing, with the recruitment of only the smaller
males. First maturation length for both sexes resulted in 11.5 mm – carapace
length - (11.5 mm in males and 11.2 mm in females). Reproduction in M.
amazonicum is continuous or periodic a gradual increase during the months
from October to March. The most common sites housed, as inner regions of
tidal channels or holes (common in Amazon estuary) sites are preferentially
sought by mature females for spawning and juvenile growth. Von Bertalanffy
growth parameters obtained were very similar between the sexes, where L ∞ =
44.8 mm and K = 0.35 for males and L ∞ = 46.5 and K = 0.31 for females.
Mortality and exploitation obtained was in maximum sustainability and the
management should be treated fairly care. In this situation, any increase in
effort may result a state of over-exploitation of growth. Allied to near
commitment of the stocks of M. amazonicum of the socio economic fishing is no
different from other systems of coastal fishery Para: poor education, poor
performance of professional associations, chain productive complex and that its
main underprivileged. We suggest the statistical monitoring of production, the
delineation of the minimum capture length in 4.5cm; suppression of fishing with
matapis in headwater areas of creeks and tidal channels, a census of users and
the use of models bioeconomic that include major aspects of its biological and
productive chain.
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