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The calanoid copepod Calanus sinicus is present throughout the year in the Bohai Sea, and is transported by the China Coastal Current southwards during winter. The seasonal movement of C. sinicus throughout its distribution should result in the genetic homogenization of the species. We tested the hypothesis of the absence of population structure in C. sinicus by analyzing the nuclear ribosomal region ITS-1 ( n = 197, 303 bp) and the mitochondrial gene, cytochrome b apoenzyme (cytb) of C. sinicus ( n = 155, 318 bp) from locations in Taiwan, S. Korea, and Okinawa, Japan. Twenty-eight haplotypes were identified from the ITS-1 gene and the most numerous haplotype ( n = 160) was found everywhere except in S. Korea. Nine haplotypes were identified from the cytb gene and the two most numerous haplotypes ( n = 140) were widespread. An excess of singletons characterized the haplotype networks of ITS-1 and cytb genes. Pairwise F comparisons among samples suggested that samples from S. Korea, S. Taiwan Strait, and Taipower Plant were significantly different from all other samples suggesting a high degree of structured populations in C. sinicus, for the ITS-1 gene. In the contrary, no population structure was detected with the cytb gene. Pairwise F comparisons among samples collected at different water depths in Turtle Island suggest that populations at depth may contribute to the genetic differentiation of C. sinicus. The two genes yielded conflicting genetic signals as the aforementioned geographic and depth-related population demarcations were observed only with the ITS-1 gene. [ABSTRACT FROM AUTHOR]

We investigated the susceptibility of Mesocyclops aspericornis and Aedes aegypti larvae to mosquito larvicidal phytochemicals: piperine and eugenol and the predation efficiency of the adult female M. aspericornis on Ae. aegypti larval instar-I and late II at the sublethal concentration of piperine and eugenol. Both prey and predator were susceptible to both the phytochemicals; however, the lethal concentration of either phytochemicals recorded for Ae. aegypti did not exert mortality on the copepods. The predator's latent time was significantly longer in the phytochemical medium than control. The encounter frequency was significantly higher in control than in the phytochemical medium. For instar-I larvae, the post-encounter attack probabilities were not affected by the tested phytochemicals. However, for instar-II, the post-encounter attack probability was lower in eugenol treatment than in either the control or piperine. The escape and post-escape survival probabilities of larvae were substantially lower in phytochemical treatments than in the control. However, the overall copepod-imposed mortality did not differ significantly between the control and the phytochemical medium. In conclusion, both the phytochemicals modify the copepod feeding behavior without affecting the copepod incurred total larval mortality. Therefore, application of these phytochemicals along with M. aspericornis for mosquito control is advisable. [ABSTRACT FROM AUTHOR]

The diversity and abundance of cyclopoid copepods were investigated at four stations along the hydrothermal vent at Kueishantao Island, north-eastern Taiwan. Zooplankton samples were collected by surface tows. Qualitatively, 21 species of cyclopoids belonging to five genera and three families were observed. Our analysis revealed a number of abnormal protrusions (TLAs) on cyclopoid copepods, which were more frequent on the dorsal body surface and in members of the family Corycaeidae. The number of TLAs was highest at the hydrothermal vent plume (HVP) zone and among adult copepods. The potentially high levels of toxic minerals erupting from the hydrothermal vents as well as low pH and high temperatures may weaken the copepods' exoskeletons, thereby increasing susceptibility to infections, indicated by the HVP-related increase of tumoural processes. It is suggested that some of these abnormalities are related to the occurrence of symbiotic tantulocarids, a topic yet to be studied in this interesting environment. [ABSTRACT FROM AUTHOR]

Swarming behaviour of copepods was studied at a coral reef in Lungdong Bay, northeastern Taiwan. Copepod distribution was documented by underwater photography and samples were obtained by SCUBA diving, deploying plankton nets, and suction devices. Copepod assemblages found at Lungdong Bay comprised four copepod orders (Calanoida, Cyclopoida, Harpacticoida and Poecilostomatoida). A new representative ofDioithonasp swarmed predominantly in summer (April to September 2008). The average density of the swarms was positively affected by temperature. Both the position and the average density were negatively affected by typhoons. Abundances were highest at the reef bottom, followed by the sea bottom outside the reef, in March and April 2008. In May, the highest densities were found at the water surface outside the reef. Adult females dominated the stage composition only at the reef surface during April, whereas early copepodids were most abundant at all other sampling dates and sites. [ABSTRACT FROM AUTHOR]

The South China Sea is the world's largest marginal sea. To understand the zooplankton community structure during monsoon transition period we investigated the copepod composition, abundance and distribution at six stations along a transect line in the subtropical South China Sea during the autumn of 1999. In the present study, 22 major zooplankton taxa were found, with Noctilucales, calanoid copepods and poecilostomatoid copepods being the most abundant of the overall zooplankton counts. We identified a total of 37 copepod species, in 25 genera, belonging to 19 families. The numerically most dominant genera wereParacalanus,CalocalanusandOncaea. Communities of zooplankton and copepods of the northern South China Sea demonstrated varied spatial distributions during the investigated period. The present study provides the composition of zooplankton and copepod community structures in the shallow mixed layer of the subtropical South China Sea during the northeast monsoon transition period. [ABSTRACT FROM AUTHOR]

We examined the effects of food and light on the swimming behavior of nauplii of the cyclopoid Apocyclops royi (Lindberg, 1940) (Copepoda: Cyclopoida) and the calanoid Pseudodiaptomus annandalei Sewell, 1919 (Copepoda: Calanoida). Several behavioral parameters such as swimming patterns, speed, and trajectories exhibited distinct ontogenetic differences between the two species. When algae Isochrysis galbana (Haptophyta: Isochrysidales) were offered as food to the nauplii of A. royi, they showed fast circle swimming behavior, while nauplii of P. annandalei never exhibited such behavior, neither with, nor without algae. The different behavioral patterns between the nauplii of both species suggest they both have different foraging strategies in detecting and capturing food. [ABSTRACT FROM AUTHOR]

The western North Pacific north of Taiwan is an area with high oceanographic complexity, both biological and physicochemical. The northward flowing Kuroshio Current passes here and turns northeastward at the break of the East China Sea continental shelf, inducing an upwelling. We used a NorPac plankton net with opening-closing mechanism to take plankton samples at six depth levels (0, 50, 100, 150, 200, and 250 m) in four time series (00:00, 08:00, 15:00, and 21:00 local time) within 24 hours. Planktonic copepods were identified to species level when possible; depth and time of collecting, and abundance in individuals/m3 were recorded. Different patterns of diel vertical migration (DVM) were established for the dominant species, such as normal DVM in Paracalanus aculeatus, Clausocalanus furcatus, Temora discaudata, and Canthocalanus pauper, reverse DVM in Oithona atlantica, no apparent DVM in Oncaea venusta and Subeucalanus mucronatus, and bimodal vertical distribution in Clausocalanus mastigophorus and Cosmocalanus darwini. Four sampling groups and four copepod species assemblages were defined by using cluster analysis. Each of these sampling groups and species assemblages is characterized by a different DVM pattern. [ABSTRACT FROM AUTHOR]

The copepod assemblage in the coastal waters of southwestern Taiwan was studied in January, June, and October 1997. Sixty-six species of copepods were found in samples collected in the upper 5 m of the water column. Abundant species included Acrocalanus gracilis , Canthocalanus pauper , Clausocalanus arcuicornis , Clausocalanus furcatus , Euchaeta rimana , Oncaea media , Paracalanus nanus , Temora turbinata , and Undinula vulgaris. Small copepods (<1 mm) made up the greatest proportion of the copepod community in terms of numerical abundance. Small- and medium-sized (1-2 mm) copepods contributed almost equally to the total copepod dry weight biomass. Large copepods (>2 mm) made up <5% of the copepod community in terms of numerical abundance and <20% in terms of dry weight biomass. [ABSTRACT FROM AUTHOR]

Day and night abundance of copepods in the coastal waters off southwestern Taiwan was studied during a cruise on 26-28 December 1997. A total of 14 zooplankton samples (7 daytime and 7 nighttime) was taken at seven stations using a one-meter mouth opening net with 333 μm mesh, and a Hydrobios flowmeter mounted in the centre of the mouth. The mean numerical abundance of copepods was 123 ± 69 ind./m3. In all, 67 species of copepods belonging to 16 families and 31 genera were identified. Among these, Paracalanus aculeatus (32% of the numerical total of copepods), Acrocalanus gracilis (31%), and Oncaea venusta (11%) were the most dominant species and occurred at every station. Most species were more abundant during the day than at night. Both the index of species diversity and that of species number of copepods were higher at the northern stations and decreased toward the southern stations at night, but behaved in the opposite manner during the day. From the results of cluster analysis, four station groups were formed: daytime northern stations, daytime southern stations, nighttime northern stations, and nighttime southern stations. The daytime northern station group was most distinct from the others. Four copepod groups were also distinguished and are herein discussed. [ABSTRACT FROM AUTHOR]

A foreword to the supplement of Volume 29 of the "Journal of Plankton Research" is presented.