11th ICRS Abstract book - Nova Southeastern University

Poster Mini-Symposium 10: Ecological Processes on Today's Reef Ecosystems
10.355
Nutrients And Herbivores: What Do We Know About Their Relative Importance
On Coral Reefs?
Jennifer SMITH* 1
1 NCEAS, University of California, Santa Barabara, Santa Barbara, CA
Coral reefs are among the most diverse and productive ecosystems on the planet but are
also significantly threatened by numerous natural and anthropogenic disturbances. Phase
shifts or alternate stable states where reef building corals are replaced by fleshy algae
have become more and more common. While large scale global impacts such as climate
change are clearly important, local impacts such as overfishing and nutrient pollution can
also alter community dynamics. The relative importance of these top-down and bottomup
controls on reef community structure have been debated by scientists for years. Thus
my goals were to test the independent and interactive effects of nutrient enrichment and
herbivore exclusion on benthic community structure on a coral-dominated reef in Hawaii
and to follow this empirical approach with a global meta-analysis. My results show that
both nutrients and herbivores are important in regulating benthic community structure but
more importantly, they do so in different ways. Herbivores tend to reduce fleshy algal
abundance while promoting the abundance of calcifying algae and coral. Nutrient
enrichment alone tends to enhance algal growth rates but not necessarily abundance as
herbivores can often consume this extra production. Finally the simultaneous effects of
herbivore removal and nutrient enrichment lead to different benthic assemblages, largely
dominated by fleshy algae. Results from both empirical and meta-analytic approaches
suggest that overfishing and nutrient pollution are important to the management and
future conservation of coral reefs.
10.356
Natural Lesions, Recovery And Partial Mortality in A Population Of Montastraea
Annularis At A Caribbean Reef
Elvira ALVARADO CH.* 1 , Alberto ACOSTA 2
1 Facultad de Ciencias Naturales, Universidad Jorge Tadeo Lozano, Bogota, Colombia,
2 Facultad de Biologia, Pontificia Universidad Javeriana, Bogota, Colombia
Populations of Montastraea annularis are showing signs of decline evidenced by high
partial and total mortality, and low recruitment rates. Due to the high number of ramets
(n= 9646) with partial (42%) and total (12%) mortality found in 102 colonies of M.
annularis in a Marine Protected Area of Colombia, we followed 88 healthy ramets to
observe type, size and duration of natural lesions. During a year, six types of lesions were
found. 47% were caused by predation and 35% by interaction with algae. Bleaching
(8%), interaction with sponges (1%) and with borrowing organisms (2%) as well as
yellow blotch disease (0.5%) were the other type of natural lesions. Most lesions were
less than 5cm2but some were as big as 60cm2. Size of lesions was not correlated with
type. From May through September abundance of lesions increased affecting between 10
and 50% of superficial area of ramets. 83% of the lesions recovered,13% did not and 4%
changed type. In general lesions from predation and bleaching recovered in less than
three months, while those caused by interaction with algae did not. Nevertheless we
observed that some lesions caused by predation (N=13), bleaching (N=7) and yellow
blotch (N=3), were invaded by algae turning into patches of partial mortality. In most of
the lesions with algae, recovery was rare and lesions grew and became permanent
features. By the end of the year, 25% of the ramets had partial mortality. These results
suggest that chronic perturbations caused by predation and more frequently and intense
bleaching events can be part of the causes for the decline in cover of M. annularis at the
Caribbean reefs, as algae quickly invade these lesions.
10.357
Response Of Hard Bottom Fish Assemblages To Red Tide Outbreaks Off Southwestern
Florida.
David SNYDER* 1
1 CSA International, Inc., Stuart, FL
Fish kills from red tide outbreaks have been reported off Florida’s west coast for decades, but
rarely has the response of fish assemblages been directly observed for particular habitats.
Following multiple red tide outbreaks during the summer and fall of 2005 and 2006, resident
fishes either died or emigrated from hard bottom habitats in nearshore (5 to 7 m) and offshore
(12 to 15 m) waters offshore Venice, Florida. Dead or dying fishes observed during 2005 and
2006 were reef-associated forms such as eels, sea basses (Serranidae), grunts (Haemulidae),
porgies (Sparidae), jawfishes (Opistognathidae), filefishes (Monacanthidae), and
porcupinefishes (Diodontidae). Survey transects established for monitoring epibiota within
nearshore (n = 18 transects) and offshore (n = 5 transects) sites during 2005; but prior to the
initial red tide outbreaks, allowed qualitative assessment of pre-outbreak fish assemblages. In
fall of 2007, fishes were censused along these same transects following a summer with no red
tide outbreaks. In total, 41 taxa had re-colonized the hard bottom areas, several of which were
not present prior to the 2005 and 2006 outbreaks. Overall, Lagodon rhomboides, Serranus
subligarius, Sparisoma sp., Halichoeres bivittatus , Epinephelus morio, Diplectrum formosum,
Diplodus holbrooki, and Lutjanus synagris accounted for 71% of the numbers of fishes
observed in 2007. Taxa observed were represented by adult, juvenile, and newly settled
individuals. Qualitative differences in species composition among years, depths, and transects
were visualized with ordination analyses on a binary resemblance matrix. The results are
compared to other documented cases of reef fish recovery following catastrophic mortality
10.358
Comparison Of The Feeding Ecology Of The Introduced Snapper lutjanus Kasmira And
Native Goatfishes in Hawai`i
Brett SCHUMACHER* 1 , James PARRISH 2,3
1 Division of Aquatic Resources, Hawaii Dept. of Land & Natural Resources, Honolulu, HI,
2 Hawaii Cooperative Fishery Research Unit/Dept. of Zoology, USGS/University of Hawaii at
Manoa, Honolulu, HI, 3 Hawaii Cooperative Fishery Research Unit/Dept. of Zoology,
USGS/University of Hawaii at Manoa, Honolulu
Lutjanus kasmira (Family: Lutjanidae) has a broad native geographic range, and is found in
near-shore reef habitats from Eastern Africa through Polynesia. However, it was not present in
Hawai`i until it was deliberately introduced during the mid-twentieth century. L. kasmira was
introduced to provide a new fishery resource, but it has not gained much acceptance in this
regard. Many fishers consider L. kasmira to be a nuisance, and blame it for declines in catches
and populations of native fishery species. L. kasmira is purported to compete with and/or
depredate a variety of resource species, including ornamental fish species such as Zebrasoma
flavescens (Family: Acanthuridae), food fishes such as Mulloidichthys vanicolensis (Family:
Mullidae), and crustaceans such as Ranina ranina (Family: Raninidae). To address these
concerns, we analyzed the feeding ecology of L. kasmira and three native species of goatfish:
M. flavolineatus, M. vanicolensis, and Parupeneus multifasciatus. The pair of species with the
greatest taxonomic dietary similarity was L. kasmira and P. multifasciatus. This finding was
somewhat surprising considering that our data indicate that these species feed at different times
of day. The congeners M. flavolineatus and M. vanicolensis had the second greatest dietary
similarity of the species in this study. L. kasmira was found to consume larger prey on average
than any of the native species. The suggestion that L. kasmira preys on native resource fish and
crustacean species was not supported by our data. Ultimately, our analyses did not detect
evidence of ecological interactions that would be likely to adversely affect populations of these
native fishery species through predation or competition for food.
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