In- and outdoor reproduction of first generation common sole Solea solea under a natural photothermal regime: Temporal progression of sexual maturation assessed by monitoring plasma steroids and gonadotropin mRNA expression

The development of a sole diet based on the composition of ragworm

“…Preliminary findings indicate average Hct levels of 10.2±2.7% for sole fed commercial pellets (CPEL) under intensive production conditions. In contrast, sole in outdoor ponds stocked with ragworm (Nereis virens Sars), show Hct levels of 23.9±4.7% (unpublished data) confirming the findings of Palstra et al (2015). Based on the feeding ecology of sole we hypothesise that feeding ragworm (RW) increases Hct and possibly haemoglobin (Hb) levels.…”

“…Could the lower levels found in sole fed CPEL indicate an anaemia in sole? Taking into consideration Thrall et al (2012), the data of Wood et al (1979) and Palstra et al (2015), this seems plausible. Moreover, when we stopped feeding with RW, we found that Hct levels decreased again with 30% within 21 days (unpublished data).…”

“…Effect of vitamin B12 and taurine on the alleviation of nutritional anaemia in common sole, (Solea, solea L.) Thrall et al (2012), the data of Wood et al (1979), Palstra et al (2015) and the fact that within a fish species the range of Hct levels for normocythemia tend to be relatively narrow , Hct and Hb levels in common sole fed commercial pellets indicate a moderate (nutritional) anaemia.…”

“…Common sole (Solea solea L.), kept under intensive production conditions has lower haematocrit (Hct) levels than when kept in outdoor ponds feeding on natural food (Palstra, Blok, Kals, Blom, Tuinhof-Koelma, Dirks, Forlenza & Blonk 2015). Preliminary findings indicate average Hct levels of 10.2±2.7% for sole fed commercial pellets (CPEL) under intensive production conditions.…”

Reproduction, olfaction and dominance behaviour in Senegalese sole (Solea senegalensis)

“…Another interesting aspect to discuss is that cultured common sole (Solea solea) a closely related species does not present the same problems as Senegalese sole to reproduce in captivity (Palstra et al, 2015). In this case common sole could have an adaptive social learning advantaging compared to Senegalese sole.…”