Jellyfish are often the most prominent components of plankton, with severe consequences
for fisheries and tourism. However, in tropical regions, there is much
uncertainty about these consequences due to the lack of basic data. Our objective
was to improve the knowledge about jellyfish in the Western Atlantic, with an
emphasis on understanding diversity, abundance, and distribution patterns. Samples
were collected at 34 stations in 1995 using a 300-lm-mesh Bongo net. The
21 species identified belonged to Hydromedusae (11), Siphonophora (nine), and
Scyphomedusae (one). The overall mean density was low (5.2 5.3 ind. m
3).
Total Hydromedusae biomass was 130.86 mg C m
3, and total Siphonophora
biomass was 19.04 mg C m
3. Chelophyes appendiculata (Eschscholtz, 1829) was
the most frequent species captured in the oceanic samples, and Aglaura hemistoma
(Peron & Lesueur, 1810) was the most common in the neritic region. The
latter species is sometimes characterized as a bloom associated with the most polluted
and eutrophic river plumes. The main role of jellyfish species in the area is
as a higher-order carnivore. A cross-shelf significant difference (P < 0.05) was
registered, with higher species numbers in oceanic regions and higher densities
and biomass in neritic regions.
Jellyfish are often the most prominent components of plankton, with severe consequencesfor fisheries and tourism. However, in tropical regions, there is muchuncertainty about these consequences due to the lack of basic data. Our objectivewas to improve the knowledge about jellyfish in the Western Atlantic, with anemphasis on understanding diversity, abundance, and distribution patterns. Sampleswere collected at 34 stations in 1995 using a 300-lm-mesh Bongo net. The21 species identified belonged to Hydromedusae (11), Siphonophora (nine), andScyphomedusae (one). The overall mean density was low (5.2 5.3 ind. m3).Total Hydromedusae biomass was 130.86 mg C m3, and total Siphonophorabiomass was 19.04 mg C m3. Chelophyes appendiculata (Eschscholtz, 1829) wasthe most frequent species captured in the oceanic samples, and Aglaura hemistoma(Peron & Lesueur, 1810) was the most common in the neritic region. Thelatter species is sometimes characterized as a bloom associated with the most pollutedand eutrophic river plumes. The main role of jellyfish species in the area isas a higher-order carnivore. A cross-shelf significant difference (P < 0.05) wasregistered, with higher species numbers in oceanic regions and higher densitiesand biomass in neritic regions.
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