11th ICRS Abstract book - Nova Southeastern University

14.495
Crisis Of Coral Metapopulations in Okinawa, Southern Japan
Kazuhiko SAKAI* 1
1 Tropical Biosphere Research Center, University of the Ryukyus, Okinawa 905-0227,
Japan
Coral communities on coral reefs are declining worldwide by global climate change and
local degradation of coral reef environment. In Okinawa Prefecture, southern Japan,
coral communities have been declining, but the status of the community varied greatly
among islands. After the 1998 mass-coral bleaching, percent cover of corals was
decreased by 80% around Okinawa I., but the cover remained relatively high at Kerama
Is., which is located at 30 km west of Okinawa I. Coral communities are more healthy at
Sakishima Is., which are at >300 km southeast of Okinawa I. I obtained the following
results from ecological studies that I have been conducting since 1980 in Okinawa I.
1) Recovery of coral communities in Okinawa I. was reduced greatly after the bleaching;
2) For broadcasting spawning corals, Kerama Is. was the source area of larval supply to
Okinawa I.; 3) The reduced resilience of coral communities in Okinawa I. was caused by
decreased larval supply during two years after the bleaching and low survival rate of
juvenile corals that were recruited abundantly in 2001; 4) Settlement of coral larvae in
Okinawa I. decreased greatly after Acanthaster outbreak that started in Kerama Is. in
2001; 5) Coral metapopulations are likely to be separated between Okinawa-Kerama and
Sakishima regions even for spawning corals whose larvae disperse long distance. The
observed great reduction in supply of coral larvae in Okinawa I. may indicate that whole
coral communities within the area of larval dispersal (coral communities with in
connected reefs) lose the recovery potential rapidly when global climate change and local
degradation of coral reef environment progress simultaneously.
14.496
Distribution Of The Hermatypic Corals in Dongshan, Fujian Province, China And
The Possible Link To The Tropical Warm Current Kuroshio
Jiansheng LIAN* 1 , Hui HUANG 1 , Jianhui YANG 2 , Xiubao LI 1
1 LMB, South China Sea Institute of Oceanology, Chinese Academy of Sciences,
Guangzhou, China, People's Republic of, 2 South China Sea Institute of Oceanology,
Chinese Academy of Sciences, Guangzhou, China, People's Republic of
Along mainland China's coast, the northmost marginal distribution of the hermatypic
coral community was found in Dongshan, Fujian Province (23.5°N~23.8°N). Dongshan
is located in the southern tip of the Taiwan Strait, facing Luzon Strait to the east. It is
interesting to observe an unusual phenomenal that there is no hermatypic corals
distribution below Dongshan until Daya Bay (22.5°N~22.9°N). The distance between
Dongshan and Daya Bay is about 330 km and 1 degree in terms of latitude. We carried
out an extensive and systematic survey of the hermatypic coral status in Dongshan using
line transect method from 2005 to 2007 to study the distribution range and try to find out
why the marginal distribution of the hermatypic coral community can reach to Dongshan.
A total of 58 stations were surveyed. Six 10 meters transect lines were completed for
each station with two depth contours.
Five species of the hermatypic corals was recorded: Favia speciosa, Cyphastrea serailia,
Turbinaria peltata, Leptastrea sp., Goniopora sp. , ordered by the extent of their
distribution range. The first three are dominant species. Comparing the earlier survey
conducted from 1995 to 1997, two species Porites lutea and Acropora pruinosa,was
disappeared, however, a new species Goniopora sp. was recorded and the three dominant
species were the same. This indicated fast species turnover rate by species colonization.
In terms of the live coral cover, the highest total coral cover was 33%, and Turbinaria
peltata was the most dominant (its coral cover can reach to 31%).
We also observe that the water mass along Dongshan area is high salinity and high
temperature compare to that of nearby area and the lowest water temperature is 14 degree
Celsius.
Combined evidences suggested the water mass along Dongshan area is strongly
influenced by the tropical warm current Kuroshio.
Poster Mini-Symposium 14: Reef Connectivity
14.497
Genetic Population Structure in A Widely Distributed Tropical Species Of Sea Cucumber,
holothuria (Halodeima) Atra.
Timothy WERNER* 1,2 , Derek SKILLINGS 3 , Benita CHICK 4
1 Biology, Boston University, Boston, MA, 2 New England Aquarium, Boston, 3 University of
Hawaii, Kaneohe, HI, 4 Boston University, Boston, MA
Holothuria atra has one of the widest geographic distributions for any sea cucumber, ranging
longitudinally from the Red Sea and Western Indian Ocean to the Panamaic region of the
eastern Pacific. Typically it is locally abundant throughout its range, although this may be
affected by the extent to which it is exploited as part of the international food trade. H. atra is
capable of reproducing both sexually and asexually, a trait that it shares with only a small
percentage of holothurians. We performed a population genetics analysis using 411 nucleotide
bases of CO1 mitochondrial DNA from more than 600 individuals of H. atra sampled
throughout its range, with the majority drawn from Indonesia and the Hawaiian Islands. Data
were analyzed to determine evidence for population structure at multiple geographic scales,
such as between regions separated by long distances and well-defined biogeographic barriers,
and within sub-regions that included principally the Indonesian and Hawaiian archipelagoes.
Based on an analysis of molecular variance (AMOVA) from Indonesian populations, most of
the genetic variability (~80%) was explained by variation within local populations, and no
obvious phylogeographic patterns were observed. In contrast, there was a significant genetic
break between the Northwest Hawaiian Islands and the main Hawaiian Islands, even though the
east-west geographic extent of this island chain is approximately two-thirds that of the
Indonesian islands. Our results are discussed in the context of long-distance larval dispersal,
physical barriers to gene flow, and reproductive strategy.
14.498
Human Exploitation Of Invertebrates in Seagrass Meadows in East-Africa
Lina NORDLUND* 1 , Johan ERLANDSSON 1 , Martin GULLSTROM 2
1 Department of Systems Ecology, Stockholm, Sweden, 2 Department of Zoology, Stockholm,
Sweden
Seagrasses form dense vegetative meadows which are dominating habitats of the coastlines
around the world. Seagrass meadows are of ecological importance providing high biodiversity
and production of both plants and animals. They are vital for fish as well as invertebrates, since
they use these habitats for foraging, protection against predators, and as nursery grounds. The
seagrass meadows play a significant role in the coastal environment as they often function as a
link between mangroves and coral reefs. They provide protection against coastal erosion and
many commercially important species use seagrass meadows as their habitat, which gives the
meadows great economical value. Due to the high productivity and the significant role for
coastal fisheries, seagrass meadows constitute a great direct value for humans in many tropical
rural communities.
The study objective is to investigate how collection of invertebrates in seagrass meadows
influences the seagrass ecosystem in East-Africa. The study was performed by collecting
biological data and interviewing invertebrate collectors in Mozambique and Tanzania.
Abundance, biomass, and community structure of invertebrates, as well as seagrass
characteristics have been compared between exploited and unexploited sites.
The results show that invertebrate collection negatively affects abundance, biomass, and
community composition of invertebrates in the seagrass meadows. Since seagrass and coral reef
ecosystems are closely linked, there is a high possibility that the associated coral reef also will
be affected by decreasing quantities of migrating invertebrates as well as less available feed for
reef associated animals entering the seagrass ecosystem to forage.
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