ABSTRACT
In order
to study the segregated distribution of the three most abundant jellyfish
species in the southern Gulf of Mexico, a total of 85 stations were sampled
during an oceanographic cruise from 19 May to 18 June 2006. Trawling took place
from surface to a maximum depth of 200 m, using a Bongo net with a 61 cm mouth
diameter and 333 and 500 μm mesh sizes. Temperature and salinity were recorded.
Samples were preserved in 4% formalin, neutralized with sodium borate, and
changed to 70% ethylic alcohol after 24 hours for conservation. The jellyfish
data were standardized to 100 m3 of filtered water. A total of
10,610 jellyfish were collected from the 333 μm mesh size net, of which eight
species represented 88.49% of the total density: Aglaura hemistoma, Liriope
tetraphylla, Nausithoe punctata, Clytia hemisphaerica, Persa incolorata, Obelia spp., Clytia folleata and Eutima gracilis. The former three
species are the subject of this study. The results obtained indicate that the
high density areas of these three species have a segregated distribution.
Segregation values (White’s index) recorded between pairs of specie were very
high: L. tetraphylla - A. hemistoma, 0.88; L. tetraphylla - N. punctata, 0.86 and A. hemistoma - N. punctata, 0.84. The spatial
distribution of the high density areas of these species fits well with the
three hydrodynamically different areas: A.
hemistoma in Campeche Bank, L.
tetraphylla on the Campeche and Tabasco shelves and N. punctata in Campeche Bay. This spatial distribution pattern
corresponds to their main habitat and reproductive habits of the species, as
well as the influence of the hydrodynamics that dominate each area.