The marine cyclopoid Oithona similis sensu lato Claus, 1866, is considered to be one of the most abundant and ubiquitous copepods in the world. However, its minimal original diagnosis and the unclear connection with its (subjective) senior synonym Oithona helgolandica Claus, 1863, may have caused frequent misidentification of the species. Consequently, it seems possible that several closely rel...

In order to characterize the zooplankton community at the Vitória Bay estuarine system (Southeastern Brazil), samples were collected in 10 sampling stations during a three-year study (1998-2000), every three months. A total of 64 taxa were identified. Copepoda contributed with the highest species number (49) in the community, especially with Acartia lilljeborgi, Acartia tonsa, Paracalanus parvu...

Oithona spp. are probably the most abundant and ubiquitous copepods in the world’s oceans. However, knowledge of their development and growth rates is scarce compared to that of calanoid copepods. In the present laboratory study, we determined the survival, development and growth rates of the naupliar stages of Oithona davisae under different temperature regimes and food concentrations. Nauplia...

We studied the feeding behavior of the nauplii and adult females of the marine cyclopoid copepod Oithona davisae in the laboratory. Functional response experiments showed that O. davisae can feed on a broad size range of prey but that high clearance rates only occur in a narrow prey size range. Neither the nauplii nor the females were able to feed on Nannochloropsis oculata (2.5 mm), but . 4 mm...

Oithona spp. is considered the most abundant and ubiquitous copepod genus in the marine environment, often outnumbering calanoid copepods throughout the year. Previous studies have argued that one of the reasons for such success is that the respiration rate of Oithona spp. is insensitive to temperature changes and lower than in calanoids. However, comprehensive data on the thermal biology of th...

We investigated predation rates of small copepods, primarily species of Oithona, on microprotozooplankton and net growth rates of these prey at several locations in the Ross Sea, Antarctica, during an austral summer (January 1997; US JGOFS Process Study II). Ciliates, particularly non-loricate ciliates, contributed substantially to the carbon ration of Oithona spp., averaging 90% body Cd~1, whi...

Spatial and temporal variations of reproduction variables the two cyclopoid copepods Oithona nana Giesbrecht, 1893 similis Claus, 1866 were evaluated monthly from September 2007 to August 2008 in four ponds at different salinities solar saltern Sfax, Tunisia, under hypersaline conditions. Along salinity gradient abundance O. declined 14,900 ± 15,200 ind. m-3 (A1) 6,800 7,200 (C31) 13,800 17,100...

Metazooplankton abundance, biomass (<80 μm, 200-500 μm and >500 μm) and community structure in the Ahe atoll were studied together with their relationships with environmental factors (temperature, salinity, wind) and trophic factors (phytoplankton, bacteria, heterotrophic nanoflagellates (HNF) and ciliates) during three periods in 2008-2009. Meroplankton, mainly bivalve and gastropod larvae, wa...

Since the first description of Marteilia refringens (Paramyxea) in flat oysters Ostrea edulis in 1968 in the Aber Wrach, Brittany (France), the life-cycle of this parasite has remained unknown. However, recent studies, conducted in the 'claire' system, have proposed the planktonic copepod Acartia grani as a potential intermediate host for the parasite. Nevertheless, experimental transmission of...