11th ICRS Abstract book - Nova Southeastern University

14.470
Recent Invasion Of The Tropical Western Atlantic By An Indo-Pacific Deep-Sea
Snapper
Tonatiuh TREJO-CANTWELL* 1 , Brian W. BOWEN 1
1 University of Hawaii, Hawaii Institute of Marine Biology, Kaneohe, HI
Deep-sea snappers (Lutjanidae) in the genus Etelis are represented by 3 species (E.
carbunculus, E. coruscans, E. radiosus) in the Indo-Pacific Ocean, but only a single
species (E. oculatus) in the Atlantic. Many other marine organisms exhibit evolutionary
connections between the Indo-Pacific and Atlantic oceans, but the pathway and timing of
these connections remain largely unknown. Phylogenetic analyses of 507 bp of the
mtDNA cytochrome b gene indicate a close affinity (approximately 1.5% divergence)
between Indo-Pacific populations of E. coruscans and western Atlantic populations of E.
oculatus, two morphologically similar snappers. These data indicate a colonization
pathway from the Indo-Pacific around South Africa and directly into the tropical western
Atlantic, a pattern also observed in recent studies of gobies (genus Gnatholepis) and
angelfishes (genus Centropyge). During recent interglacial periods, relaxation of the cold
Benguela Current along the coast of Africa may have allowed fish larvae in the tropical
Agulhas Current to enter the southern Atlantic and be transported by the South Equatorial
Current directly into the western Atlantic. The goby and angelfish data indicate invasions
of Indo-Pacific reef fishes into the western Atlantic occurred approximately 145,000 and
250,000-500,000 years ago, respectively. Using conventional mtDNA molecular clock
estimates for marine fishes (approximately 2% per million years between lineages), our
data for E. coruscans and E. oculatus suggest an Atlantic founder event occurred
approximately 750,000 years ago. Collectively these findings demonstrate a novel
biogeographic pathway for colonization between ocean basins that clearly enhances
Atlantic reef biodiversity.
14.471
Glass Sponge Reefs On The Canadian Continental Shelf: Population Structure And
Reproduction
Andia CHAVES-FONNEGRA* 1 , Sally P. LEYS 1
1 Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada,
Edmonton, AB, Canada
Glass sponges are unusual animals that have the ability to form massive reefs. Sponge
reefs reached their maximum during the Jurassic, declined during the Cretaceous, and
were thought extinct until several were discovered in the early 1990s at depths of 100 to
250 m on Canada’s Pacific coast. Glass sponges have a siliceous skeleton that is fused
into a rigid framework. Compared to coral reefs, sponge reefs have a lower richness of
framework species; only three hexactinellid sponge species form the reef framework:
Aphrocallistes vastus, Farrea occa and Heterochone calyx. But, like corals, they can
form patches or mounds where they tend to grow very close to each other, thus forming a
net three-dimensional structure. Sexual reproduction by larvae has only been documented
in one individual, suggesting that sustainability of the reef could be by asexual
reproduction. To determine the extent to which sponge reefs might be clonal, and bud to
form massive single colonies of the same genotype, tissue compatibility experiments
were carried out with different individuals (non-self) and with pieces of the same
individual (self). The remote operated vehicle ROPOS was used to survey and collect
tissue samples from reefs located in the Strait of Georgia, Canada. Initial results suggest
that 10/15 (67%) pairs of self fragments stayed adhered to one-another, whereas only
3/23 pairs (13%) of non-self fragments remained adhered to one-another after 12 hrs.
These results suggest that reefs are not formed exclusively by clones, implying that
recruitment must occur by larval dispersal. A total of five patches of live sponge reefs are
found in the Galiano Ridge reef complex and eight at Fraser Ridge reef. Microsatellite
markers are being designed to confirm these preliminary results and to determine whether
the reef complexes of framework hexactinellid sponges constitute different populations.
Poster Mini-Symposium 14: Reef Connectivity
14.472
Understanding Potential Patterns Of Larval Dispersal From Grouper Spawning
Aggregations – Drifter Vial Studies From Raja Ampat Islands, Eastern Indonesia
Joanne WILSON* 1,2 , Peter MOUS 2 , Chris ROTINSULU 2 , Andreas MULJADI 2
1 Indonesia Program, The Nature Conservancy, Sanur, Indonesia, 2 The Nature Conservancy,
Sanur, Indonesia
Raja Ampat Islands in Eastern Indonesia contain the world’s highest coral reef biodiversity and
are a global priority for conservation. Recently, a network of 7 Marine Protected Areas (MPAs)
covering an area of 900 000 ha was declared in this area. The Nature Conservancy and partners
are supporting local governments and communities to develop a zoning system within these
MPAs. Understanding and incorporating biological patterns of connectivity is one of the
fundamental principles used in the design of MPA networks. Grouper spawning aggregations
are a key target for inclusion in no-take areas. Understanding the patterns and scale of larval
dispersal from these sites will inform MPA design. Biological patterns of connectivity result
from a combination of biological and physical factors. As a first step, drifter vials were used to
determine local and regional scale current patterns. Vials were released from two spawning
aggregation sites, one during the spawning season in 2005 (1000 vials) and another in 2006
(5000 vials). Between 15-30% of vials were recovered. The majority were recovered within the
first month and within 20 km of the release sites which is within the MPA network. However, a
small number of vials traveled over 500 km with one vial traveling to Papua New Guinea
‘against’ major equatorial currents. This study demonstrates the potential importance of these
sites for local and regional replenishment and hence the importance of protecting spawning
aggregations in no-take areas. It also demonstrates the importance of understanding local
currents when interpreting the role of large scale current features in connectivity. The next step
is to compare these data with the extensive database on marine genetic connectivity available
for this region.
14.473
Scale-Dependent Variability in Larval Supply in Coastal Kenya: Towards Estimating
Connectivity Of Reef Sites
James MWALUMA 1 , Boaz KAUNDA-ARARA* 2 , Melckzedeck OSORE 1 , Vidar
ORESLAND 3
1 Kenya Marine & Fisheries Research Institute, Mombasa, Kenya, 2 Fisheries and Aquatic
Sciences, Moi University, Eldoret, Kenya, 3 Marine Insitute, Fisheries Board, Stockholm,
Sweden
Reef fishes are known to be demographically open with pelagic larval phase that reseeds distant
populations. The dispersal of larvae to reef sites is therefore a function of hydrodynamics, larval
behaviour and interactions thereof. Metacommunity models have either been based on local
communities connected to a regional pool or on a set of spatially segregated communities
connected by individual inputs. In this study we examined the levels of connectivity of local
and regional fish assemblies based on an estimate of larval supply to reef sites covering a span
of > 100 km and across habitat patches spanning a distance of < 10 km on the Kenyan coast.
Larval supply was quantified using plankton tows when peak larval abundance is expected
along the coast during 2006 and 2007. Results show species-specific differences in larval
supply on a south-north gradient, with the presence of more spatially truncated dispersal in
some species (e.g. Lethrinidae, Scaridae and Apogonidae). This is contrasted to species with
medium (Siganidae) and long distance dispersal regimes (e.g. Holocentridae). Models of
dispersal for the dominant larvae show differences in kurtosis. The results indicate differences
in dispersal distances of larvae along the Kenyan coast. Patterns of distribution indicate possible
differences in spawning sites and times and existence of mechanisms that truncate dispersal.
These results have implications for setting outer spatial limits for stock management,
connectivity of reef sites and for siting of marine reserves.
381