11th ICRS Abstract book - Nova Southeastern University

14.491
Distributions And Diversity Hot-Spots Of Gobies And Blennies Throughout The
Tropical Western Atlantic: Implications For Managing Caribbean Reef Fish
Diversity
Christy PATTENGILL-SEMMENS* 1 , Peter AUSTER 2 , Brice SEMMENS 3,4
1 Reef Environmental Education Foundation (REEF), Key Largo, FL, 2 University of
Connecticut, Groton, CT, 3 NOAA Fisheries, Seattle, WA, 4 NOAA Fisheries, Seattle
We took advantage of a large database of reef fish presence and abundance to assess the
biogeographic patterns of Gobidae and Blennidae, two families of reef fishes that are
often over-looked in community assessments. Over the past decade the Reef
Environmental Education Foundation (REEF) Volunteer Survey Project has generated
over 95,000 visual surveys of reef fish assemblages from 5,800 sites throughout the
tropical western Atlantic. Because these surveys exhaustively characterize fish taxa, they
provide a unique set of information on rare and cryptic species. Previous studies of
species ranges have found little support for a relationship between larval duration and
range size. On the other hand, members of Gobidae and Blennidae tend to have variable
larval stages and exhibit greater habitat specificity than other reef fish families. We found
Gobidae and Blennidae diversity to be disjointed across the Caribbean basin. Moreover, a
small number of disparate locations exhibited surprisingly high levels of diversity. These
areas of high diversity may have resulted from: a) oceanographic bottlenecks or
entrainments that yield high recruitment, b) high habitat diversity , or c) both. Regardless
of the mechanism, these areas should be given special consideration in regional
conservation efforts aimed at biodiversity.
14.492
Genetic Connectivity in The Branching Vase Sponge (callyspongia Vaginalis)
Across The Florida Reef Tract And Caribbean
M. B. DEBIASSE* 1 , V. P. RICHARDS 1 , M. S. SHIVJI 1
1 National Coral Reef Institute, Nova Southeastern University, Dania Beach, FL
The Porifera constitute a substantial fraction of the biomass on coral reefs and frequently
have higher species diversity than corals and algae, making this phylum an important
model for the investigation of reef connectivity. We examined genetic connectivity in the
common branching vase sponge, Callyspongia vaginalis, by analyzing DNA sequence
variation in 511 bp of the mitochondrial cytochrome oxidase I (COI) gene in 401
individuals sampled from 16 locations throughout the Florida reef tract and Caribbean.
Populations of Callyspongia vaginalis were highly genetically structured over the study
area (ΦST = 0.48, P < 0.0001), including over distances as short as tens of kilometers
within the Florida reef tract, and had a significant overall pattern of isolation by distance
(P = 0.0002). However, nonsignificant pairwise ΦST values were also found between a
few Florida sampling sites suggesting that long distance dispersal, perhaps by means of
fragmentation, may occur over continuous, shallow coastlines. Indeed, sufficient gene
flow appears to occur along the Florida reef tract to obscure a signal of isolation by
distance (P = 0.164), but not to homogenize haplotype frequencies over 465 km from
Palm Beach to the Dry Tortugas. Statistical parsimony analysis revealed two highly
divergent haplotypes from Honduras suggestive of cryptic speciation. Inferences from a
nested clade analysis supported the pattern of restricted gene flow and isolation by
distance in the Caribbean, and suggested a northward range extension of C. vaginalis
from a hypothesized Central American ancestral population into the Gulf of Mexico and
Florida. The extensive genetic structuring in this common reef sponge is consistent with
expectations based on typically short sponge larval durations, suggesting that sponge
recruitment to coral reefs may be largely local source driven.
Poster Mini-Symposium 14: Reef Connectivity
14.493
Stuck in A Hole: Extreme Differences in Genetic Differentiation Between Closely Related
Caribbean Tube Blennies
Ron I. EYTAN* 1 , Michael E. HELLBERG 1
1 Department of Biological Sciences, Louisiana State University, Baton Rouge, LA
Acanthemblemaria spinosa and A. aspera are closely related species of tube blennies inhabiting
coral reefs in the tropical Western Atlantic. Both are obligate dwellers of vacated invertebrate
holes in corals and hard substrates and co-occur across much of their ranges. They have similar
life histories and pelagic larval durations, and as such should be expected to show similar levels
of genetic differentiation among populations. Instead, an initial survey of mitochondrial
sequence variation (741 bp of cytb) revealed extreme differences between the two species in
their degree of population subdivision. While both species rarely share mitochondrial DNA
(mtDNA) cytb alleles among populations, the genetic distance between alleles is over 10-times
greater within A. spinosa than A. aspera. The objective of this study was to determine whether
ecology, mutation rates, or taxon age underlies the difference between these species. To
establish which of these mechanisms are responsible, sequences were collected from two single
copy nuclear DNA markers (scDNA). A. spinosa has more specialized habitat requirements
than A. aspera and more specialized species are expected to share fewer alleles among
populations than generalists. On the other hand, if the species have the same propensity to share
alleles between populations but the genetic distances among those alleles are greater for one
species than the other, and that species is not much older, differences in mutation rates may be
responsible. The scnDNA sequences show a pattern similar to that for mtDNA, with far greater
genetic distances within A. spinosa than A. aspera. Phylogenetic comparisons with other
Acanthemblemaria species show that species age is not a factor. This suggests that a higher
mutation rate in A. spinosa, rather than greater ecological specialization, is responsible for the
extreme differences in genetic subdivision between these two species. However, demographic
differences may also be a contributing factor.
14.494
Ichthyoplankton Assemblages in Atolls Along Cagayan Ridge, Sulu Sea, Philippines
Wilfredo CAMPOS* 1 , Pacifico BELDIA 1
1 Division of Biological Sciences, University of the Philippines Visayas, Miag-ao, Iloilo,
Philippines
The Sulu Sea possesses unique hydrographic features which result in high endemicity and
biodiversity in the basin. It is believed that the atoll reefs of the Cagayan Ridge form a major
corridor through which planktonic (fish) larval dispersal is facilitated. To examine this,
ichthyoplankton surveys were conducted in April 2006 to determine the abundance,
composition and distribution of fish eggs and larvae in the immediate vicinity of the Tubbataha
Reefs and Cagayancillo Island. In general, egg and larval densities were highest inside the
atolls and decreased with distance from the reef margin. Densities in Cagayancillo were 2.9
eggs/m 3 and 49.7 larvae per 100m 3 . These were comparable to observations in Tubbataha (2.2
eggs/m 3 and 35.2 larvae/100m 3 ). Larvae of coastal fishes dominated the assemblages in both
reef systems, although the proportion of larvae of deep water groups (e.g., myctophids and
gonostomatids) was much higher in Tubbataha. The distribution of larval assemblages
corresponded somewhat with the formation of island wakes. The potential role of these atoll
reefs as sources of propagules for downstream reef systems is examined further through results
of short-term drift experiments.
386