The influence of rearing temperature on early development and growth of spotted wolffishAnarhichas minor(Olafsen)

Abstract

Temperature influenced the developmental rate, survival and early growth of eggs and embryos of spotted wolffish, Anarhichas minor (Olafsen), an interesting candidate for cold water cultivation. The total incubation period decreased from 220 days at 4 °C (880 daydegrees), to 177 days at 6 °C (1062 daydegrees) and 150 days at 8 °C (1200 daydegrees) in these experiments. The proportion of normal embryos and survival of eggs until hatching were highest when the eggs were incubated at 6 °C. During the incubation period, the embryo and yolk sac size at 280 daydegrees was not significantly different but at 850 daydegrees the embryo size was inversely related to temperature and the remaining yolk sac size positively correlated with the incubation temperature. The transformation of yolk to body mass during incubation appeared to be most efficient at 4 °C, and the embryos hatched with a larger visible yolk sac at 6 and 8 °C. The largest larvae (wet‐weight) hatched from the largest eggs and the egg groups incubated at the lowest temperature (4 °C). There was no effect of temperature on meristic characters. During 6 weeks post‐hatching, all larvae from the three temperature groups were fed formulated dry feed in excess at 8 °C in low water‐level raceway systems. During startfeeding, the larvae from eggs incubated at the lowest temperature (4 °C) showed the highest growth rates (SGR). Best survival of larvae was noted among batches incubated at 6 °C.

Artificial light at night: implications for early life stages development in four temperate freshwater fish species

“…Earlier hatched larvae benefit from rich food resources that shrink with increasing larvae density and thus have growth advantages (Houde 1975;Shepherd and Cushing 1980;Karjalainen 1992;Welker et al 1994;Kestemont et al 2003). However, it is known from aquaculture that earlier hatched larvae are often smaller, perform worse and show higher mortality (Gray 1928;Brooke 1975;Hansen and Falk-Petersen 2001).…”

A review of the culture potential of spotted wolffish Anarhichas minor Olafsen

“…The nature of egg and larval development in the species, with hatching of well-developed, large fry ready to be fed on formulated food (Falk-Petersen et al, 1999;Hansen and Falk-Petersen, 2001a), has helped dodge some of the traditional bottlenecks often experienced in production of marine larvae, i.e. high mortality in the larval stage and obligatory initial feeding with live food items.…”

Identification of Stress Sensitive Genes in Hyperthermic Atlantic Salmon (Salmo salar) Embryos by RAP-PCR

“…Temperature, nutrition, antibiotics and genetics have been shown to be associated with a number of deformities ranging from heart failure and missing septum transversum to fusions and shortening of vertebrae (Sandnes et al 1992;Toften and Jobling 1996;Sadler et al 2001;Takle et al 2005). Fish seem particularly vulnerable for development of deformities during embryogenesis (Koo and Johnston 1978;Sato et al 1983;Graham and Hop 1995;Wang and Tsai 2000;Hansen and Falk-Pedersen 2001;Ornsrud et al 2004a, b). The mechanisms causing these deformities are still unclear, but hyperthermia is known to alter several functions, including metabolism, respiration, membrane function, and involves dramatic changes in the expression of specific genes.…”