Feeding and egg production of the planktonic copepod Calanus sinicus in spring and autumn in the Yellow Sea, China

Spring and autumn reproduction of Calanus sinicus in the Yellow Sea

“…3). Compared with the unsuccessful summer recruitment (Zhang et al 2007), the relatively high EPR, HS and NS in the nearshore area implied the high potential of population increase, which could also be confirmed by the high proportion of N1 to C3 (>~80% of total abundance) collected by a finer zooplankton net (Huo et al 2008). We infer that the recovery of the nearshore population in late autumn (Wang & Zuo 2004, Sun 2005 In contrast to Zhang et al (2005), who recorded high HS in Calanus sinicus, we found that HS in April varied largely (4 to 85%; Fig.…”

“…Uye & Murase 1997, Niehoff 2000, Runge et al 2006, whereas the inner lipid reserve may have varying roles during reproduction of different species (Lee et al 2006, Niehoff 2007, Jónasdóttir et al 2008). In the Yellow Sea, Calanus sinicus can accumulate lipid in the oil sac; however, previous studies have focused on the effect of food (Uye & Murase 1997, Zhang et al 2005, Huo et al 2008, leaving the role of lipid reserve during reproduction unknown. (2) Other factors such as temperature, body size, age and feeding history can also influence reproduction either directly or indirectly (Hirche et al 1997, Rey et al 1999, Campbell & Head 2000, Rey-Rassat et al 2002, Bunker & Hirst 2004, Castellani & Altunbaaş 2006.…”

“…; Huo et al 2008), which could barely meet the metabolic requirements of C. sinicus females (Li et al 2004), thus there would not be sufficient external nutrition to initiate final gonad maturation. Similarly, Zhang et al (2007) ascribed null egg production in the YSCWM during summer to food limitation, but unfortunately that study did not examine gonad development.…”

Molecular gut content analysis demonstrates that Calanus grazing on Phaeocystis pouchetii and Skeletonema marinoi is sensitive to bloom phase but not prey density

“…This heterotrophic dinoflagellate is specialized in grazing on chain-forming According to both models and empirical data, mesozooplankton such as Calanus are more likely to graze on ciliates and large diatoms than on microalgae such as P. pouchetii (Nejstgaard et al 1997, Irigoien et al 2005, Thingstad et al 2008. Protistan microzooplankton comprise a significant fraction of mesozooplankton diet (Stoecker & Capuzzo 1990), and in certain cases can be preferred prey species as assessed by clearance rate measurements in the laboratory (Hansen 1995, Gasparini et al 2000 and in field studies (Kleppel et al 1991, Leising et al 2005b, Huo et al 2008). This may in part be due to the higher nutritional value of microzooplankton (reviewed in Stoecker & Capuzzo 1990, but see Koski et al 2005, Huo et al 2008 and/ or to greater conspicuousness of ciliates caused by their larger size and higher motility (Jakobsen et al 2005) …”

Ciliate (Euplotes sp.) predation by Pseudodiaptomus annandalei (Copepoda: Calanoida) and the effects of mono-algal and pluri-algal diets

“…Numerous studies proved that copepods can utilize considerable proportions of ciliate production (Kumar 2003;Huo et al 2008;Fileman et al 2010). Ciliate consumption rates by certain copepods were significantly higher than those for algae (Gifford and Dagg 1988;Vadstein et al 2004;Loder et al 2011;Küppersm and Claps 2012), and clearance rates for ciliates were equal as they cleared large algal cells (Tiselius 1989;Gifford and Dagg 1991).…”