Methods for Manipulating
Yellow Perch Spawning Cycles

OTT#1104

Technology

Mr. Binkowski has developed a process that involves conditioning yellow perch, through modification of water temperature and photoperiod regimes, to spawn anytime on the 12 month calendar once sexual maturity is reached.  Out-ofcycle spawning broodstocks can be developed to produce gametes every 2-3 months.  Although each particular broodstock will still only spawn one time each year, this process allows production of multiple broodstocks that each spawn at different times.  Having yellow perch gametes available this often creates an economic advantage by producing a valuable resource throughout the year.

Perch aquaculture has yet to realize the increased efficiency that has benefited other domesticated species of livestock and poultry through selective breeding programs.  Some applications of intentional selection to other aquaculture species have demonstrated that domestication improvements, similar to those achieved with other livestock, are possible.  Current culture strategies for yellow perch are too dependent on wild populations as sources of eggs and fingerlings for grow-out.  Essentially there are no commercially available domesticated broodstocks of this species.  An understanding of the potential genetic resources that exist in wild perch stocks is limited.  Knowledge of the influence of the environment on gene expression and the degree of inheritability of aquaculturally important traits will be necessary to derive the full benefit of artificial breeding.  These factors will only be clarified through the development of domesticated stocks and the implementation of controlled breeding programs.

Current practice limits production of young fish for grow-out to a single annual crop that would be available in late spring through early summer.

Unfortunately, with a single annual crop rearing pattern, aquaculturists have to invest in large holding facilities which are required toward the latter months of the rearing cycle to support the increased biomass of the crop.  These facilities would be unneeded earlier in the growing cycle, and would be wastefully idle through the summer and into the fall.  Also, with a seasonal synchronization of production of market-sized perch, oversupply at harvest time could result in undesirable effects on price.  This dilemma requires spreading production over time.  Neither retention of market-sized adults to control supply, nor holding large numbers of fingerlings in stunted conditions for later grow-out provide ideal solutions to this problem, since both of these strategies incur additional holding costs.

Features/Benefits

  • More Crops – Gametes can be produced every 2-3 months rather than once a year
  • Year round supply – Perch can be conditioned to spawn any time during the year
  • Safer – The process does not involve hormones or chemicals to induce spawning
  • Healthy – Yellow perch are low in fat and calories and high in protein and omega-3 fatty acids
  • Toxin free – Fish are reared in clean water and fed a controlled diet to ensure safety
  • Flexibility – Large holding facilities can be scaled down due to constant year-round production
  • Domesticated Broodstocks – Broodstocks have been selected for growth and health attributes

Intellectual Property

US Patent 7,836,852.
Genetically selected broodstocks for faster growth and larger adult fish.

Markets

Yellow perch have long been a popular member of the Friday night fish fry in many Great Lake shore line communities.  The commercial retail value of yellow perch remains high at $13-16 per pound.    Annual harvests from all the Great Lakes averaged more than 23 million pounds from 1950 to 1970, but just 5.75 million pounds from 1990 to 2000.  During the 1970s the high market values and decline in commercial catches led to heightened interest in commercial culture of this species, primarily in mid-western states.  A distributor in the Midwest has market value for all aquaculture in the U.S. is approximately $1 billion.

Yellow perch flesh is very high quality, with a firm, flaky texture and mild flavor. The meat has less fat (<1 percent) than other popular cultured food fish, and also fewer calories per 100-gram serving (91). Yet it is high in protein (19.5 percent) and contains a modest level of omega-3 fatty acids (0.3 percent). The lower fat content of yellow perch can result in a longer shelf life. The commercial harvest of yellow perch is prohibited in some areas because of low populations and closes periodically in other areas because of concerns about contaminants.  As the commercial harvest of yellow perch declines, the market for farm-raised fish is becoming increasingly valuable.

*Statistics taken from Agricultural Marketing Resource Center and www.thefishsite.com

Inventor (s)

Fred Binkowski is a Senior Scientist at the School of Freshwater Sciences at the University of Wisconsin-Milwaukee.  He obtained his M.S. in Zoology (Fisheries Biology) at the University of Wisconsin-Milwaukee.  His research is focused on improving Great Lakes aquaculture production.  Fred has been the UW Sea Grant program aquaculture specialist form more than two decades, delivering expert advice on aquaculture and encouraging the development of new commercial aquaculture enterprises.

For further information please contact:
Jessica Silvaggi, Ph.D.
Senior Licensing Manager
UWM Research Foundation
1440 East North Avenue
Milwaukee, WI 53202
Tel: 414-906-4654
Please reference: OTT ID. 1104