Categories
vol-32ECOLOGICAL OBSERVATIONS ON THE ABUNDANCE,
DISTRIBUTION OF HOLOTHUROIDS (ECHINODERMATA:
HOLOTHUROIDEA) IN THE RED SEA COAST, EGYPT
*ABDEL RAZEK, F.A.; ** EL-SHIMY, N.A.; *ABDEL RAHMAN, S.H.
AND *OMAR, H.A.
* National Institute of Oceanography and Fisheries, Alexandria, Egypt
** Faculty of Science, Assuit. University
*E-mail: [email protected]
Keywords: Holothuria species, Red sea, distribution, population structure seasonal abundance,
gut sediments with habitat.
ABSTRACT
Deposit-feeding holothurians are prominent members of many shallow and deep
benthic communities. Increasing attention is being given to the effects of international trade
on the environment, especially in situations where biodiversity conservations is opposed to
exploited industries such as fisheries. Effect of habitat conditions on abundance,
distribution and population structure of three important holothurian species in Red sea
Hurghada area were studied. Individual of Holothuria atra population were found to vary
between 9.5 and 28.5 cm length with a model length of 21.5 cm. It was abundant during
winter and spring in algal and sea grass habitats. Holothuria hawaiiensis Individuals were
found to vary between 15.5 cm & 43.5 cm in length. Its frequent length categories starting
from 25.5 cm to 41.5 cm. This species was abundant during winter and spring in sandy
habitat with algae, as well as living and dead coral with a clear occurrence in site III.
Bohadshia vitiensis individuals had length range varying between 14.0 & 42.0 cm length
with most frequent categories varying from 21.5 up to 35.5 cm length. A narrow seasonal
fluctuation in abundance was noted. The distribution of this species was found to be
correlated with sand, algae and sea grass habitats. There was a high correlations between
the gut sediment contents of the studied species and the sediment composition of the
surrounding sites. The continuation of this study on all the other areas of Red Sea world
make it possible to introduce sustainable management measures.
