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Title
A study has been led from September 2016 to February 2017 in the great barrier reef of Toliara and the complex reef of Sarodrano. It concerns about assessing the density of Zooxanthellae in Acropora sp during the hot season in two different sites. The sample of healthy Acropora sp was collected in two gradients of depth (0-5m) and (5-10m) every two months. For the first two months, the density of zooxanthellae in Grande Vasque was respectively about 1,4*106 cells.cm-² and 1,54*106 cells.cm-² in (0-5m) depth and (5-10m). In Arakaivo, there is no significant difference in terms of density between the gradient of depths. In November and December we have observed a significant value between depth either in Grande Vasque or Arakaivo. And a significant difference was noted between the two sites in terms of density. The zooxanthellae dwells the most in the apical part of coral. There is a significant difference either between apical and middle or apical and basal part of coral. The Zooxanthellae set up likely the most on the top of Acropora sp so that it conquered the daily light. And about the carbon sequestration, the basal part of coral has a higher amount of CO2 than the middle or apical part of coral. This result is very important to diagnose the state of coral reef ecosystem before, during and after one event. Keys words : Acropora sp, Zooxanthellae, Density, CO2, GRT, Sarodrano
Authors
FOHY Nicolas
Research Topic
Abstract
This study was led within the company of holothuriculture MH.SA within its farm in
Belaza in the south western of Madagascar from may 2009 to april 2010. Its purpose was to
optimize the endobenthics juveniles of H. scabra breeding conditions in order to increase the
production of sea cucumber reaching the marketable size. Studies on the effect of the density
and the temperature on survival and the growth of juveniles were made and tests of food for
juveniles based on the sediments were realized.
The results of the studies showed that the density of breeding of 26 individuals m- ²
instead of 20 allows a good growth and survival of H. scabra juveniles. Moreover, the
increase of the temperature with 30°C makes possible to obtain a better growth and survival
rates of juveniles and the fall of the temperature during fresh season can be mitigated by the
use of greenhouse which help to increase the temperature of 4°C.
The replacement of the sediments coming from the zone of the herbaria by taken
mud of the mangrove zone and the reduction of its quantity in 15 buckets by basins instead of
120 before are beneficial because it does not harm the survival and the growth rates of the
animals and decreases the expenses related to the filling of the basins.
Key words: optimization, breeding, H. scabra, juveniles, endobenthic, MH.SA
Volume
1
Date of publication
May 5, 2001
Institution (University)
Institut Halieutique et des Sciences Marines
Page numbers (pp)
62