Influence of asexual reproduction on the structure and dynamics of Holothuria (Halodeima) atra and Stichopus chloronotus populations of the Great Barrier Reef

2001 ◽  
Vol 52 (2) ◽  
pp. 205 ◽  
Author(s):  
S. Uthicke
Keyword(s):  
Great Barrier Reef ◽  
Asexual Reproduction ◽  
Fission Products ◽  
Barrier Reef ◽  
Frequency Distributions ◽  
Near Shore ◽  
Wet Weight ◽  
Stichopus Chloronotus ◽  
Holothuria Atra ◽  
Individual Size

To determine the effect of asexual reproduction by transverse fission on the population structure of holothurians, ensities and individual weights of Holothuria atra (JÄÄger,1833)and Stichopus chloronotus (Brandt, 1835)were measured over a 26-month period on near-shore reefs of the Great Barrier Reef. Densities of H.atra (0.01—0.69 individuals m –2 )and S. chloronotus (0.11—1.67) did not increase during periods of intense asexual reproduction, and the density on each reef remained relatively stable.The effect of fission was clearly visible in the weight —frequency distributions of both species. The average individual wet weight in each population declined (H. atra from 105/134 g to 64/94 g in two respective populations;S. chloronotus from 128/302 g to 82/190 g in two respective populations) with the onset of fission in early winter, and more individuals in the weight range of fission products were found. The biomass followed the seasonal trend of the average weights for both species, with minimum values in winter. A conceptual model based on these and previous findings identified five possible factors (mortality, habitat stability, optimum individual size, food availability, larval supply) involved in promoting or repressing transverse fission, and the model indicated the consequences for the population.

An organic Geochemical analysis of Terrestrial biomarkers in a transect of the Great Barrier Reef Lagoon

1989 ◽  
Vol 40 (3) ◽  
pp. 275 ◽  
Author(s):  
BR Currie ◽  
RB Johns
Keyword(s):  
Great Barrier Reef ◽  
Barrier Reef ◽  
Terrestrial Organic Matter ◽  
Higher Plant ◽  
Pentacyclic Triterpenoid ◽  
Lipid Biomarker ◽  
Additional Input ◽  
Near Shore ◽  
Benthic Sediments ◽  
Geochemical Analyses

Organic geochemical analyses of benthic sediments from a Northern Queensland coastal transect indicate that most terrestrial organic material is confined to near-shore sediments (<10 km offshore). Traces of higher plant material reach the inner fringes of the Great Barrier Reef, as indicated by the presence of pentacyclic triterpenoid alcohols (PTA) in near-reef sediments. A likely source of these alcohols is mangroves. PTA and long-chain normal alkanes appear to be the most reliable of the lipid biomarker classes analysed in assessing the distribution of terrestrial organic matter along the transect. Other terrestrial biomarker classes (sterols, normal fatty acids and fatty alcohols) present in the sediment do not show good correlation with distance from the land. This is believed to be due to the additional input of these biomarkers from planktonic sources.

Asexual reproduction does not produce clonal populations of the brooding coral Pocillopora damicornis on the Great Barrier Reef, Australia

Coral Reefs ◽  
2005 ◽  
Vol 25 (1) ◽  
pp. 7-18 ◽  
Author(s):  
C.D.H. Sherman ◽  
D.J. Ayre ◽  
K.J. Miller
Keyword(s):  
Great Barrier Reef ◽  
Asexual Reproduction ◽  
Barrier Reef ◽  
Pocillopora Damicornis ◽  
Brooding Coral

Long term trends in population dynamics and reproduction inHolothuria atra(Aspidochirotida) in the southern Great Barrier Reef; the importance of asexual and sexual reproduction

2012 ◽  
Vol 93 (4) ◽  
pp. 1067-1072 ◽  
Author(s):  
Benjamin V. Thorne ◽  
Hampus Eriksson ◽  
Maria Byrne
Keyword(s):  
Population Density ◽  
Great Barrier Reef ◽  
Sexual Reproduction ◽  
Gonad Index ◽  
Fission Products ◽  
Reproductive Pattern ◽  
Barrier Reef ◽  
Significant Difference ◽  
Low Incidence ◽  
Population Maintenance

Population density and the presence of fission products ofHolothuria (Halodeima) atrawere investigated in surveys taken over 5 years (2006–2010) in the Capricorn Bunker Group, Southern Great Barrier Reef. These surveys were undertaken to document population density over time and assess the potential that asexual reproduction contributes to population maintenance. Over the 5 years a low incidence of fission was evident year-round, with an increase in July and August (13 and 27% of the population, respectively). There was a positive correlation between population density and the presence of fission products across all surveys. Although density fluctuated, there was no significant difference between months or sites. Despite the potential increase that might be expected from fission followed by regeneration, density fluctuated around a mean of 0.77 ind. m−2. Examination of gonads of the small (asexual and sexual reproduction) and large (sexual only) morphs ofH. atraindicated a difference in reproductive pattern. Many small morphs lacked gonads during winter and, when they developed gonads, the gonad index (GI) was low. The GI pattern of the small morph indicated that they spawned in summer. In comparison the large morph had conspicuous gonads through the year. The GI of the large morph was high in winter and summer indicating greater, more prolonged spawning activity in these individuals.

A historical and contemporary consideration of the diet of the reef manta ray (Manta alfredi) from the Great Barrier Reef, Australia

2017 ◽  
Vol 68 (5) ◽  
pp. 993 ◽  
Author(s):  
M. B. Bennett ◽  
F. F. Coman ◽  
K. A. Townsend ◽  
L. I. E. Couturier ◽  
F. R. A. Jaine ◽  
...  
Keyword(s):  
Great Barrier Reef ◽  
Stomach Contents ◽  
Barrier Reef ◽  
Calanoid Copepods ◽  
Frequency Distributions ◽  
Manta Alfredi ◽  
Filter Mechanism ◽  
Manta Ray ◽  
Reef Manta Ray ◽  
Arrow Worms

The preserved stomach contents from the manta ray, collected in 1935, that provided the basis for the 2009 taxonomic resurrection of the species Manta alfredi, were examined. The majority of the material comprised calanoid copepods (61.7%) and trypanorhynch cestodes (34.6%), with minor contributions by arrow worms, a barnacle larva and a nematode. Comparison of the size-frequency distributions of stomach contents with that of zooplankton from the Great Barrier Reef region suggest that this manta ray preferentially ingested large copepods, or that the filter mechanism used to extract prey from the water was selective for prey items over 0.8mm in length. This is the first description of the diet of M. alfredi from stomach contents, and is consistent with previous inferences about what this species consumes.

scholarly journals REPRODUKSI ASEKSUAL PADA Holothuria atra (ECHINODERMATA) DI TELUK MEDANA, LOMBOK BARAT

2017 ◽  
Vol 14 (4) ◽  
pp. 415
Author(s):  
Sigit Anggoro Putro Dwiono ◽  
Pradina Purwati ◽  
Varian Fahmi ◽  
Lisa F. Indriana
Keyword(s):  
Population Size ◽  
Asexual Reproduction ◽  
Fission Products ◽  
Research Topic ◽  
Monthly Basis ◽  
Sea Cucumbers ◽  
Fission Rate ◽  
Population Maintenance ◽  
Holothuria Atra

Beberapa jenis timun laut secara alamiah memiliki kemampuan untuk berkembang biak secara aseksual melalui pembelahan (fission). Penelitian ini merupakan studi pertama tentang reproduksi aseksual alamiah timun laut di perairan Indonesia. Di Teluk Medana, Lombok Barat, Nusa Tenggara Barat fenomena reproduksi aseksual ini ditunjukkan oleh populasi Holothuria atra. Untuk mengetahui intensitas, musim, dan peran reproduksi ini dalam memelihara populasi, dilakukan monitoring bulanan mulai bulan Pebruari 2007 sampai Pebruari 2008. Hasil tersebut menunjukkan bahwa reproduksi aseksual pada populasi Holothuria atra ini terjadi sepanjang tahun. Intensitas pembelahan (fission intensity) maksimum mencapai 32,69%, yang berarti bahwa 1/3 dari populasi melakukan pembelahan. Variasi laju pembelahan (fission rate) berkisar antara 1,79 dan 23,68%. Pada bulan Mei 2007, komponen individu hasil pembelahan hampir mencapai separuh (47,4%) dari jumlah individu keseluruhan. Ketiga indikator ini cukup untuk menyimpulkan bahwa reproduksi aseksual pada Holothuria atra di Medana berperan dalam memelihara populasi di habitat tersebut. Topik ini sangat penting diteliti mengingat peran reproduksi aseksual ini dalam mempertahankan keberadaan di alam. Several species of sea cucumbers are able to reproduce asexually through fission. This study is the first report on fission of holothurian populations in Indonesian waters. At Medana Bay,West Lombok, fission was demonstrated by Holothuria atra population. To determine the intensity, season, and the role of fission on the population maintenance, monitoring was conducted on monthly basis, from February 2007 until February 2008. This study revealed that fission occurred throughout the year. Maximum fission intensity was 32,69%, implying that one third of the population underwent fission. Fission rate which was illustrated by the frequency of fission products during 13 month of observations, varied between 1.79 and 23.68%. In May 2007, fission products composed nearly half (47.4%) of the population. These three indicators may be sufficient to conclude that asexual reproduction in Holothuria atra population at Medana Bay might contribute significantly in maintaining its population size. This research topic seems important to be carried out considering the role of asexual reproduction in maintaining its natural population.

Population genetics of the fissiparous holothurian Stichopus chloronotus (Aspidochirotida) on the Great Barrier Reef, Australia

Coral Reefs ◽  
1999 ◽  
Vol 18 (2) ◽  
pp. 123-132 ◽  
Author(s):  
S. Uthicke ◽  
J. A. H. Benzie ◽  
E. Ballment
Keyword(s):  
Population Genetics ◽  
Great Barrier Reef ◽  
Barrier Reef ◽  
Stichopus Chloronotus
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