Effects of salinity on osmoregulation during the embryonic development of the bullseye puffer (Sphoeroides annulatusJenyns 1842)

Abstract

To evaluate the effect of salinity on the hatching rate, hatching time, survival percentage, osmoregulation pattern and the incidence of abnormalities in newly hatched larvae, embryos of Sphoeroides annulatus (Jenyns 1842) were exposed to 5, 12, 19, 26, 33, 35 and 40 psu. The hatching percentage (HP), survival percentage (PS), normal larvae (PN), deformed larvae (PD) and hatching time (HT) were significantly affected by salinity (P < 0.05). The embryos exposure to 5 psu caused that HP, PS, and PN had lower values (2.6 ± 0.32, 7.78 ± 0.88 and 70.37 ± 7.75% respectively), PD and HT had the highest values 26.67 ± 7.54% and 55.53 ± 0.59 h respectively. However, the survival of newly hatched larvae was not possible in 5 ups, though it was in 40 ups. Osmotic pressure (OP) remained constant in each salinity, whereas isosmotic points changed from 435.5 mOsm kg−1 in 21 h post fertilization to 342.8 mOsm kg−1 at 47 h post fertilization, obtaining a pattern of hyper‐osmoregulation at lower salinities and hypo‐osmoregulation in higher salinities. This study is the first carried out on embryos of this species; therefore, the obtained information is essential to improve strategies and growing conditions in their initial development.

The influence of salinity on egg incubation and early larval development of the flameback angelfish Centropyge aurantonotus

“…In this study, there was a trend of the incubation time to be inversely proportional to the increase in water salinity, fact observed in other marine fish species (Pérez‐Robles et al, 2014). Changes in the egg incubation time can affect the body size, the amount of yolk sac and oil drop reserves of newly hatched larvae of some fish (Gracia‐López et al, 2004).…”

The effects of environmental salinity on the growth and physiology of totoaba Totoaba macdonaldi and shortfin corvina Cynoscion parvipinnis

“…It seems evident that there is no general rule applying to the growth response of fishes to salinity. Besides being species-specific, other biotic factors, such as age, body length and mass, as well abiotic factors, such as temperature and ionic composition of culture water, have been shown to interact with salinity to determine growth of fishes (Imsland et al, 2001;Sampaio & Bianchini, 2002;Wuenschel et al, 2004;Fielder et al, 2005;Varsamos et al, 2005;Pérez-Robles et al, 2016).…”

Fluctuating salinity effect onSphoeroides annulatus(Jenyns 1842) physiological responses

“…To understand S. annulatus salinity adaptation, Perez‐Robles et al () studied different developmental stages (eggs/embryos, larvae and juveniles) and exposure conditions (Table ). A difference for larva or juvenile was observed when trials were done by direct exposure or by acclimation process.…”

“…Recently, the effect of constant salinity (long term) has been assessed on embryos, larvae and juveniles (Pérez‐Robles et al, ; Pérez‐Robles, Re, Giffard‐Mena, & Díaz, ). These authors concluded that S. annulatus was a strong osmoregulator since oxygen consumption rate (OCR) and ammonium excretion rate (AER) rates were stable within salinity intervals from five to 40 psu in long‐term acclimation trials (21 days); O:N showed values from 50 to 60 indicating that S. annulatus used a mixture of proteins and lipids as source of energy.…”

“…Osmoregulation and expression level of NKA were modulated according to the hypo‐ hyper‐regulation mechanisms with an iso‐osmotic point (IP) in juveniles, similar to larvae 338.9–355.9 mmol/kg but lower than embryos (342.8–435.5 mmol/kg) (Perez‐Robles et al, ). The IP was similar to related species, such as S. testudineus , (Linnaeus, ), Takyfugu obscurus (Abe, ) and T. rubripes (Kato, Doi, Nakada, Sakai, & Hirose, ; Prodocimo & Freire, ; Temminck & Schlegel, ).…”