Suspension Feeders on Sandy Beaches
3.3 Beach Morphodynamic Types and Abundances
and Population Biology of E. analoga
67
Seasonal variability in population abundances of E. analoga at two regions of
the Chilean coast is shown in Fig. 3.5. In northern Chile, the abundances were
higher at an intermediate beach (average Dean's parameter=2.9) as compared
with a site with quite reflective characteristics (average Dean's parameter= 1.4). On the other hand, two beaches examined in south central Chile,
a dissipative site (average Dean's parameter=6.6) and an intermediate beach
(average Dean's parameter=4.7), supported similar population abundances of
E. analoga. This suggests that beach types affect population abundances of
this suspension feeder just when beach types are close to or at the reflective
condition. This assertion is supported by the fact that, at those sites sampled
in south central Chile, growth parameters of E. analoga are quite similar (E.
Jaramillo, unpubl. data).
northern Chile (ca. 23 0 S)
1000000
100000
,. 10000
E
'ti
1000
c:
100
10
J
D
M
A
D
A
1996
1
1997
11998
south central Chile (ca. 39 0 S)
1000000
100000
IE
10000
'ti
1000
.!:
100
10
o D J
1994 I
FMAMSOD,JF
1995
1996
Fig. 3.5. Seasonal variability in population abundances of Emerita analoga in two areas
of the Chilean coast. The values of Dean's parameter (0) are means of the whole study
period at each beach. The sampling months at the beaches of northern Chile were July
(J) and December (D) 1996, March (M),August (A) and December (D) 1997, and August
(A) 1998