No abstract

The effects of salinity and temperature on plasma protein concentration and total haemocytic prophenoloxidase (proPO) were determined. Groups of 10 juvenile yellowleg shrimp, Penaeus californiensis Holmes, were acclimated for 20 days at different salinities (28‰, 32‰, 36‰, 40‰ and 44‰ at 25°C) or temperatures (18, 22, 25, 28 and 32°C at 36‰). While total protein levels were not affected, the quantities of proPO increased as salinity was elevated. Temperature affected both haemolymph parameters, showing a significant decrease in proPO at 32°C, and an increase of protein at 28 and 32°C. These results may help to explain the elevated disease susceptibility of shrimp at higher salinities and/or temperatures.

No abstract

The effects of salinity and temperature on plasma protein concentration and total haemocytic prophenoloxidase (proPO) were determined. Groups of 10 juvenile yellowleg shrimp, Penaeus californiensis Holmes, were acclimated for 20 days at different salinities (28%o, 32%o, 36%o, 40%o and 44%o at 25 °C) or temperatures (18, 22, 25, 28 and 32 °C at 36%o). While total protein levels were not affected, the quantities of proPO increased as salinity was elevated. Temperature affected both haemolymph parameters, showing a significant decrease in proPO at 32 °C, and an increase of protein at 28 and 32 °C. These results may help to explain the elevated disease susceptibility of shrimp at higher salinities and/or temperatures.

This study was performed to determine the growth and survival patterns of the juvenile yellowleg shrimp Farfantepenaeus californiensis cohabiting with the green feather alga Caulerpa sertularioides over a range of temperatures (18, 22, 25, 28 and 32°C) found throughout the year in the Gulf of California. From an initial weight of 46 ± 10 mg, shrimp cohabiting with green feather algae increased in weight by an average of 0.57 (±0.07), 5.44 (±0.45), 6.36 (±0.37), 7.66 (±0.26) and 5.96 (±0.59) g at 18, 22, 25, 28 and 32°C, respectively, whereas shrimp grown without seaweed increased in weight by an average of 0.28 (±0.026), 2.66 (±0.24), 3.15 (±0.49), 4.00 (±0.67), and 3.54 (±0.09) g respectively. Statistically significant differences were observed for the growth rates of juvenile yellowleg shrimp in the presence of C. sertularioides and peak growth was observed at 28°C in experiments with macroalgae. No significant differences were observed for shrimp survival except at 32°C without macroalgae, where survival was lower. These results suggest a beneficial and growth-promoting effect of cohabitation with live C. sertularioides on F. californiensis.