HYBRID ARCTIC CHAR – A NEW AQUACULTURE PRODUCT?

Arctic Char (Salvelinus alpinus) is a significant aquaculture species in cold temperate latitudes. Cultured Arctic Char sold in the United States originates from Norway, Iceland and Canada. Demand for this premium priced species exceeds supply.

Because of its temperature and light cycle requirements, commercial scale reproduction of Arctic Char has failed in south temperate latitudes. While Arctic Char grow well at New York ground water temperatures (10^oC), these temperatures are too high for successful egg/milt production and incubation. Even with photoperiod and temperature manipulations, it has been difficult to successfully reproduce pure strain Arctic Char.  

In order to find a solution to the problems of Arctic Char reproduction in south temperate latitudes, the State University of New York has been examining the potential of interspecific hybridization. The main goal of this project is to produce Arctic Char appearing progeny that reproduces well in New York.  

Arctic Char and Brook Trout naturally hybridized in the Fraser River and elsewhere. In this study, male Fraser River strain Arctic Char were crossed with female Brook Trout to produce F₁ hybrids. Subsequently only Arctic Char appearing fish were crossed to form the next generation. After nine generations, 89% had the appearance of an Arctic Char (no vermiculations), 53% had no dorsal markings, while 36% had dorsal spots. Further, 51% F₉ hybrids had red spots with no halos and 49% had blue halos around red spots.

Previous studies of Arctic Char x Brook Trout hybrids, have reported decreased fertility and sterility. It has been suggested this may be due to differences in chromosome number causing problems with their pairing during meiosis. It was hypothesized that since only fish that produced viable gametes would leave progeny, in subsequent generations, fertilization and hatching success would be improved. While fertilization, eye-up and hatching success was variable between pairings, there was no net improvement between generations.

Throughout the ten generations of this study, reproductive success of hybrid Arctic Char was higher than pure strain Arctic Char at New York photoperiods and groundwater temperatures. (Average fertility was 83.2%, eye-up rate was 45.2% and hatching rate was 34.8%).  While it is too early to recommend Arctic Char hybrids to cold water fish farming, these results encourage further consideration of its suitability.