Economic valuation of coral reef resources in Semporna-valuation of potential tourism

No Abstrac

The dynamics of leiognathidae in a tropical demersal ichthyofaunal community

Cleveland Bay (Townsville), on the tropical northeastern shoreline of Australia, is a small bay (225 km²) that historically has not been subjected to commercial trawling. However, the unexploited environment of Cleveland Bay is characterized by frequent disturbance by natural processes such as resuspension of sediments on the bottom due to currents generated by wind-waves and monsoonal trade winds, high terrigenous sedimentary input from riverine systems along the coast, and lowering of salinity due to increased flooding. This presents a rare opportunity to gain necessary biological and ecological information on the demersal ichthyofauna that may be typical of the unexploited bays in the Indo-Pacific region. The species composition and structure of the ichthyofauna of Cleveland Bay were studied using a strict sampling regime to provide a general view of the community. In addition, the distribution and abundance of leiognathids (Pisces: Leiognathidae) and their biology (growth, reproduction) were investigated. The extent of predation by synodontids (Pisces: Family Synodontidae) on leiognathids was estimated also. The ichthyofaunal community of Cleveland Bay was multispecific but consisted of only one assemblage at the scale of the whole bay (which is <20 m deep). Total biomass, leiognathid biomass, and leiognathid densities were highly variable at very small spatial and temporal scales (<20 m range of depth, < 1,000 m; daily) and these patterns persist through time (over years) in the frequently disturbed sedimentary regime of Cleveland Bay. The abundance of leiognathids persists despite high predation levels on recruits. This maintenance of high abundance may be explained by their fast growth and iteroparous reproduction. In addition, the leiognathids feed on zoobenthos and zooplankton that can respond rapidly to changes in the primary production of Cleveland Bay (due to resuspension of nutrients and recycling of nutrients by epibenthic biota). The strategy taken in studying this community (a combination of the top-down and bottom-up approaches) provided ecological bases for assessing the state of the ichthyofauna of Cleveland Bay and essential data for modelling multispecific, tropical demersal ichthyofauna and multispecies fisheries

Population Structure and Genetic Variability of Six Bar Wrasse (Thallasoma hardwicki) in Northern South China Sea Revealed by Mitochondrial Control Region Sequences

The genetic relationships among northern South China Sea populations of the six bar wrasse (Thallasoma hardwicki) were investigated. Fish collected from the Solomon Islands were used for geographic comparison. In 1998 and 1999, a total of 100 fish were sampled from 6 localities of the northern South China Sea and 3 localities of the Solomon Islands. Genetic variations in DNA sequences were examined from the first hypervariable region (HVR-1) of the mitochondrial control region, as amplified by polymerase chain reaction. High levels of haplotypic diversity (h = 0.944 ± 0.0016, π = 0.0224 ± 0.01171) in the HVR-1 region of the mitochondrial control region of T. hardwicki were detected. This yielded 94 haplotypes that exhibited a minimum spanning tree with a starburst structure, suggestive of a very recent origin for most haplotypes. Neutrality tests indicated that the pattern of genetic variability in T. hardwicki is consistent either with genetic hitchhiking by an advantageous mutation or with population expansion. Partitioning populations into coherent geographic groups divided the northern South China Sea samples (ΦCT = 0.0313, P < 0.001) into 3 major groups: a north-central group composed of northwestern Taiwan and northern Vietnam; a southwestern group containing southern Vietnam; and a southern group including the central Philippines. These results are in concordance with mesoscale boundaries proposed by allozyme markers, thus highlighting the importance of identifying transboundary units for the conservation and management of fisheries in the South China Sea

Variable numbers of tandem repeats (VNTRs), heteroplasmy, and sequence variation of the mitochondrial control region in the three-spot Dascyllus, Dascyllus trimaculatus (Perciformes: Pomacentridae)

The primary structure of the Dascyllus trimaculatus mitochondrial (mt) control region was determined, and conserved features were identified based on sequence comparisons to other teleostean fish species. Three termination-associated sequence (TAS) motifs, a central conserved sequence block (CSB), and a pyrimidine tract were identified, indicating that the organization of the mt control region in D. trimaculatus is similar to those reported for other teleosts. However, 2 sets of variable number of tandem repeats (VNTRs), denoted R1 and R2, which simultaneously occur at both the 5’- and 3’-ends of the mt control region are first reported herein in teleost fish. Analysis of amplification of the VNTRs indicated that heteroplasmy is common for both sets of VNTRs. VNTRs also respond to sequence length variation of the D. trimaculatus mt control region. A relatively high proportion of VNTR copy number variations and heteroplasmy indicate the potential utility of VNTRs as markers for assessing three-spot dascyllus population-level variability