Dissertation - HQ

Results 79
Figure 4.5 Perspective view of the pycnocline for the four rotations (interpolated
by cubic splines). While the cline is globally always around 70 m, local holes
and bumps largely differ from one rotation to another
“pump” water up or push it down). Cyclonic eddies may locally enrich
the water in nutrients through upwelling, while anticyclonic ones may
trap terrigenous products. In both cases, they are good candidates to
test for correlations with the abundance of larval fish.
4.3.2 Patchy distribution of fish larvae
Of the 576 MOCNESS samples, 572 could be used. The mean volume
filtered per sample was 1056 m 3 (Standard Deviation = 302 m 3 ). They
contained an estimate of 47,800 fish larvae, comprised of at least 94 families
(pelagic or deep specimen were not all sorted). Epi- and mesopelagic
species dominated the samples with more than twice as many pelagic
larvae than coral reef fish larvae. The two most abundant orders were
the Clupeiformes (mostly Engraulidae) and the Myctophiformes. 10,794
coral reef fish larvae were identified and the most common, by far, were
Acanthuridae (Table 4.1). The relative abundances of coastal vs. oceanic
taxa are comparable to those observed around another isolated atoll in
the tropical North-Pacific 74 or in the Florida Keys 184 . Compared to the
Keys, Bregmacerotidae were notably less prominent and Acanthuridae
were particularly abundant. Among these > 10,000 coral reef fish larvae,
Over 10,000 coral
reef fish larvae,
mostly pre-flexion