Effects of photoperiod and stocking density on survival, growth and physiological responses of narrow clawed crayfish (Astacus leptodactylus)

Abstract

Photoperiod and stocking density are critical factors influencing the performance of decapod crustaceans in culture, however, their influence on growth; survival and biochemical physiology of crayfish broodstock have rarely been considered. Analysis of biochemical physiology in crayfish broodstock during the non‐breeding season provides information on the energy storage requirements of broodstock for increased survival and reproductive output. Growth rate, moulting frequency, survival and biochemical physiology were measured in Astacus leptodactylus broodstock that were cultured at three different photoperiods (18L:6D; 12L:12D; and 6L:18D) and three stocking densities (10, 20 and 40 individuals m−2) during non‐breeding season. Survival of crayfish was highest at 18L:6D photophase and 10 m−2 (100%) than other treatments. Survival in the high stocking density was high when combined with 18L:6D photophase, but weight gain (WG) and specific growth rate (SGR) were higher at shorter photophase and lower stocking density. Longer photophase (18L:6D) increased stress responses, characterized by increased haemolymph lactate and glucose levels. Stocking density did not affect proximate composition of crayfish; however, individuals cultured at 18L:6D photophase had higher lipid content than other photoperiod treatments. The study demonstrated that culturing A. leptodactylus at 18L:6D photophase and 10 m−2 is critical for increased survival of broodstock.

Effect of serotonin injection on the reproductive parameters and haemolymph methyl farnesoate level in the narrow‐clawed crayfishPontastacus leptodactylus(Eschscholtz, 1823)

“…A sterile 25‐gauge needle (2.5 ml syringe) was used to withdraw haemolymph from the heart (Farhadi & Jensen, ). One ml of haemolymph samples were transferred into 50 ml tubes containing 4% NaCl and acetonitrile.…”

Elevated water temperature impairs gamete production in male narrow-clawed crayfish Pontastacus leptodactylus (Eschscholtz, 1823)

“…Mean dissolved oxygen, and pH were 7.8 ± 1 mg/L and 7.9 ± 0.2, respectively. Crayfish were fed a commercial feed containing 40.7% protein and 16.8% lipid two times per day and approximately 1% of body weight (Farhadi and Jensen, 2016). Cold water (7.5°C) was provided from outdoor tanks and aquarium heaters were used to provide the other test temperatures (11 and 19°C) (Skurdal and Taugbøl, 2002;Bugnot and López Greco, 2009a;Tropea et al, 2010).…”

Factors affecting the reproductive efficiency in crayfish: implications for aquaculture

“…Photoperiod is an environmental factor that can be easily manipulated in the laboratory. Photoperiod has a considerable effect on growth and moulting frequency (Yue, Wang, Wang & Peng 2009;Farhadi & Jensen 2015), survival, cannibalism (Farhadi et al 2014) and reproduction (Harlıo glu & Duran 2010) in A. leptodactylus. Light requirements for reproduction can vary by species.…”