Aquaculture America 2020

February 9 - 12, 2020

Honolulu, Hawaii

RAS PRODUCTION OF MARKET-SIZED ATLANTIC SALMON Salmo salar AT THE FRESHWATER INSTITUTE: HISTORICAL PERFORMANCE OF VARIOUS COHORTS

John Davidson*, Travis May, Curtis Crouse, Anna DiCocco, Thomas Waldrop, Steven Summerfelt, and Christopher Good
 
The Conservation Fund's Freshwater Institute
 1098 Turner Road
Shepherdstown, WV 25443
jdavidson@conservationfund.org
 

The Conservation Fund's Freshwater Institute (FI)  has been culturing Atlantic salmon  Salmo salar to market-size (> 4 kg) in a semi-commercial recirculation aquaculture system (RAS) for nearly a decade to assess the feasibility of this fish production  method at relevant scale. During that period,  FI has cultured salmon cohorts  with various geneti cs and life history, sex distribution (mixed sex and all-female), and ploidy (diploid and triploid), from egg suppliers in North America and Europe. A wealth of fish performance data has been gleaned from these  grow-out  trials. Atlantic salmon typically grow to 4-5 kg in FI's semi-commercial scale RAS in 23-26 months post-hatch while maintaining feed conversion ratios of 1.1-1.3. However , most cohorts have demonstrated a propensity for early maturation under  conditions common to FI's  research facility (freshwater, 14-16  o C, hard water, around-the clock feeding, etc.) .  Early maturation is generally undesirable to farmers , because  fillet  market-value is reduced due to pale flesh color, reduced product yield, and diminished lipid content. Thus , identification  and genetic selection  for  strains  that balance rapid growth with  a  reduced inclination for early maturatio n is a necessity for the growing land-based Atlantic salmon industry.

A recent grow-out trial evaluating all-female diploid and triploid  Atlantic  salmon from a European provider indicated  further progress towards development of RAS-s uited stocks. G rowth performance  of all-female diploid salmon  was comparable to the fastest  growing strains  (North American)  cultured onsite, and  percent maturation  for the all-female diploid and triploid groups  was 13.6  and 0.0%, respectively.  Overall, early maturation was substantially diminished in these cohorts compared to that of previous mixed sex populations (17 - > 50% maturity). A ll-female triploid salmon exhibited an increased prevalence of deformities, i.e. 16%, while no deformities were noted  for sampled fish from the  all-female diploid population. P ositive and negative characteristics for  all-female diploid and triploid Atlantic salmon cohorts were realized, providing information t hat will guide  RAS producers in weighing the risk/reward of these options.

A full summary of Atlantic salmon growth performance, maturation, and associated fish production conditions will be provided for cohorts produced at FI over the last ten years. Over all,  FI's research has demonstrated that  land-based  production of  market-size  Atlantic salmon in RAS is both biologically and technologically feasible.