International Journal of Marine Science 2016, Vol.6, No.27, 1-22
16
Figure 10: CCA biplot showing relationship between rare fish species identified in the peak season of the artisanal fishery
The first two ordination axes from the CCA cumulatively accounted for 100% of the variations of the species
abundance from the environmental parameters in the lean season of the semi-industrial fishery. pH was found to
be positive on the first axis and phosphates, nitrates, Revelle factor, total alkalinity and carbonate ion
concentration on the negative end of the axis. On the second axis, total alkalinity, nitrates and phosphates were on
the positive end while Revelle factor, pH and carbonate ion concentration were on the negative end.
Auxis thazard
related well with both total alkalinity and nitrates, while
Selar crumenophthalmus
related well with pH and
carbonate ion concentration.
Sardinella maderensis
also related well with the Revelle factor (Figure 11).
Figure 11: CCA biplot showing relationship between dominant fish species identified in the lean season of the semi-industrial fishery
For the peak season of the semi-industrial fishery however, the first two ordination axes explained 97.6% of
observed variations. Nitrates, phosphates, pH and carbonate ion concentration were found on the positive end of
the first axis while Revelle factor and total alkalinity were found on the negative end. Revelle factor, total
alkalinity and carbonate ion concentration were found on the negative end of the second axis while nitrates,
phosphates and pH were found on the positive end. The species
Sardinella aurita
related well with pH, while
Decapterus punctatus
related well with Revelle factor and total alkalinity (Figure 12).
Selar crumenophthalmus
, a
rare species per abundance, was found to relate well with pH, while Sepia officinalis was partially related to
carbonate ion concentration and the Revelle factor (Figure 13).
-1.0
1.5
-1.0
1.5
O.unicol
S.offici
D.rhoncu
C.hippos
L.laevig
D.margar
S.madere
T.teraia E fimbri
E.guttif
C.seneg C.lippe
S.fiatol
S.tritor
R rhinob B albida
TOTAL AL
REVELLE
PH
CARBONAT
Nitrates
Phosphat
-1.5
1.0
-1.5
1.5
D.puncta
S.aurita
B.auritu
S.madere
S.japoni
D.rh ncu
B bo ps
A.thaxar
E fimbri
S.crumen
TOTAL AL
REVELLE
PH
CARBONAT
Nitrates
Phosphat
