Spatiotemporal variation in postlarval recruitment of the Caribbean spiny lobster in the central Bahamas: lunar and seasonal periodicity, spatial coherence, and wind forcing
Db. Eggleston et al., Spatiotemporal variation in postlarval recruitment of the Caribbean spiny lobster in the central Bahamas: lunar and seasonal periodicity, spatial coherence, and wind forcing, MAR ECOL-PR, 174, 1998, pp. 33-49
A large-scale recruitment study of the Caribbean spiny lobster Panulirus ar
gus in the central Bahamas identified (1) strong spatial coherence in settl
ement to inshore nursery habitats, (2) temporal variability due in part to
stochastic wind forcing, and (3) lunar and seasonal periodicity in settleme
nt. First, we quantified lunar variation in settlement on standardized arti
ficial substrates to determine whether or not intra- and inter-annual varia
bility in recruitment could be adequately described by measuring influx of
postlarvae during the first quarter of each new moon, as suggested by previ
ous studies. Next, we compared settlement data obtained from artificial sur
face substrates to concentrations of postlarvae in the water column and ben
thic settlement. Long-term (6 yr) spatiotemporal variation in postlarval se
ttlement was then quantified at 8 sites spanning a longitudinal and onshore
distance of 43 km and 11 km, respectively. Lastly, we examined the relatio
nship between postlarval settlement and environmental variables with time-s
eries analyses. The key findings were that: (1) significant lunar (first qu
arter of lunar phase) and seasonal (fall peak) periodicities in settlement
were consistent across sites; (2) postlarval settlement varied more across
sites (similar to 600 %) than between years at a single site (similar to 50
%), and inter-site differences were consistent across time (i.e, some sites
always had higher settlement than others); (3) settlement was correlated w
ith along-shore winds blowing towards the southeast, but not with cross-she
lf winds or water temperature; (4) floating, 'Witham-type' artificial settl
ement substrates yielded an accurate index of postlarval concentration and
flux past a given point: and (5) floating substrates were a relatively poor
indicator of benthic settlement, though the relationship between surface a
nd benthic settlement may depend upon benthic habitat availability and post
larval supply. These results indicate that artificial settlement substrates
provide a reliable index of postlarval supply to inshore nursery habitats,
and that a combination of stochastic and deterministic forces influence re
cruitment over various scales of time and space.