Publication Date:
2023-07-09
Description:
In the present paper, the ecology and feeding habits of euphausiids are described. The samples were taken at the time of the NE-monsoon (1964/65) by R. V. "Meteor" in the Arabian Sea and adjacent waters. 24 species were determined. According to distribution of the species, the following marine areas can be distinguished:
Arabian Sea: 24 species, dominant are Euphausia diomedeae, E. tenera, E. distinguenda, Stylocheiron carinatum.
Gulf of Aden: 10 species, dominant are Euphausia diomedeae, E. distinguenda.
Red Sea: 6 species, dominant are Euphausia diomedeae, E. distinguenda.
Gulf of Oman : 5 Species, dominant are Euphausia distinguenda, Pseudeupbaufia latifrons.
Persian Gulf: 1 species - Pseudeuphausia latifrons.
The total number of euphausiids indicate the biomass of this group. High densities of euphausiids (200-299 and 〉 300 individuals/100 m**3) occur in the innermost part of the Gulf cf Aden, in the area south of the equator near the African east coast, near Karachi (Indian west coast) and in the Persian Gulf. Comparison with data relating to production biology confirms that these are eutrophic zones which coincide with areas in which upwelling occurs at the time of the NE-monsoon. The central part of the Arabian Sea differs from adjacent waters by virtue of less dense euphausiid populations (〉 199 individuals/100 m**3). Measurements relating to production biology demonstrate a relatively low concentration of primary food sources.
Food material was ascertained by analysis of stomach content. The following omnivorous species were examined: Euphausia diomedeae, E. distinguenda, E. tenera, Pseudeuphausia latifrons and Thysanopoda tricuspidata. Apart from crustacean remains large numbers of Foraminifera, Radiolaria, tintinnids, dinoflagellates were found in the stomachs. Quantitatively crustaceans form the most important item in the diet. Food selection on the basis of size and form appears to be restricted to certain genera of tintinnids. The genera Stylocheiron and Nematoscelis are predators. Only crustacean remains were found in the stomachs of Stylocheiron abbreviatum, whereas Radiolaria, Foraminifera and tintinnids occurred to some extent in Nematasceli sp.
Different euphausiids in the food chain in the Arabian Sea. In omnivorous species the position is variable, since they not only feed by filtering autotrophic and heterotrophic Protista, but also by predation on zooplankton. Carnivorous species without filtering apparatus feed exclusively on zooplankton of the size of copepods. Only these species are well established as occupying a higher position in the food chain.
The parasitic protozoan Tbalassomyces fagei was found on Euphausia diomedeae, E. fenera, E. distinguenda and E. sanzoi.
Keywords:
Arabian Sea; DEPTH, water; Eastern Arabian Sea; Euphauaia diomedeae; Euphausia brevis; Euphausiacea; Euphausia distinguenda; Euphausia mutica; Euphausia paragibba; Euphausia pseudogibba; Euphausia sanzoi; Euphausia similis; Euphausia tenera; Event label; Golf of Aden, Arabian Sea; Gulf of Oman; IIOE - International Indian Ocean Expedition; Indian Ocean Standard Net; IOSN; Latitude of event; Longitude of event; M1; M1_042; M1_049; M1_052; M1_062; M1_066; M1_071; M1_073; M1_077; M1_093; M1_094; M1_101; M1_104; M1_106; M1_109; M1_113; M1_114; M1_115; M1_124; M1_126; M1_129; M1_132; M1_134; M1_135; M1_136; M1_137; M1_139; M1_141; M1_145; M1_146; M1_147; M1_149; M1_150; M1_151; M1_153; M1_157; M1_158; M1_167; M1_173; M1_175; M1_180; M1_181; M1_182; M1_183; M1_184; M1_186; M1_194; M1_195; M1_197; M1_199; M1_200; M1_205; M1_209; M1_210; M1_214; M1_218; M1_220; M1_222; M1_225; M1_233; M1_234; M1_235; M1_236; M1_238; M1_239; M1_243; M1_244; M1_245; M1_247; M1_248; M1_253; M1_275; M1_277; M1_293; M1_294; M1_373; M1_379; M1_380; M1_381; M1_NET042; M1_NET049; M1_NET052; M1_NET062; M1_NET066; M1_NET071; M1_NET073; M1_NET077; M1_NET093; M1_NET094; M1_NET101; M1_NET104; M1_NET106; M1_NET109; M1_NET113; M1_NET114; M1_NET115; M1_NET124; M1_NET126; M1_NET129; M1_NET132; M1_NET134; M1_NET135; M1_NET136; M1_NET137; M1_NET139; M1_NET141; M1_NET145; M1_NET146; M1_NET147; M1_NET149; M1_NET150; M1_NET151; M1_NET153; M1_NET157; M1_NET158; M1_NET167; M1_NET173; M1_NET175; M1_NET180; M1_NET181; M1_NET182; M1_NET183; M1_NET184; M1_NET186; M1_NET194; M1_NET195; M1_NET197; M1_NET199; M1_NET200; M1_NET205; M1_NET209; M1_NET210; M1_NET214; M1_NET218; M1_NET220; M1_NET222; M1_NET225; M1_NET233; M1_NET234; M1_NET235; M1_NET236; M1_NET238; M1_NET239; M1_NET243; M1_NET244; M1_NET245; M1_NET247; M1_NET248; M1_NET253; M1_NET275; M1_NET277; M1_NET293; M1_NET294; M1_NET373; M1_NET379; M1_NET380; M1_NET381; Meteor (1964); Nematobrachion flexipes; Nematoscelis sp.; Nematoscelis tenella; Northern Arabian Sea; Number of species; Persian Gulf; Pseudeuphausia latifrons; Red Sea; Stylocheiron abbreviatum; Stylocheiron affine; Stylocheiron carinatum; Stylocheiron longicorne; Stylocheiron microphthalma; Stylocheiron suhmii; Thysanopoda aequalis; Thysanopoda monacantha; Thysanopoda obtusifrons; Thysanopoda tricuspidata; Western Arabian Sea
Type:
Dataset
Format:
text/tab-separated-values, 2440 data points
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