THE EFFICIENCY AND ECONOMICS OF BREEDING OPERATIONS IN THE AQUACULTURE INDUSTRY FOR MANY FISH SPECIES ARE SEVERELY AFFECTED BY POOR MALE REPRODUCTIVE PERFORMANCE, ESPECIALLY REDUCTIONS IN THE MOTILITY (MOVEMENT) AND FERTILITY OF SPERM. FOR EXAMPLE, SOUTHERN FLOUNDER IS AN ATTRACTIVE AQUACULTURE SPECIES WITH A STRONG MARKET POTENTIAL IN ASIA BUT THE POOR QUALITY OF THE SPERM FROM MALE BROODSTOCK RESULTS IN POOR AND UNPREDICTABLE REPRODUCTIVE SUCCESS. RECENTLY IT WAS FOUND THAT FISH PROGESTIN HORMONES CAN INCREASE SPERM MOTILITY AND FERTILITY IN SOUTHERN FLOUNDER BY BINDING TO A RECEPTOR ON SPERM, MEMBRANE PROGESTIN RECEPTOR (MPR) ALPHA, RESULTING IN ACTIVATION OF SPECIFIC SIGNALING MOLECULES INSIDE SPERM THAT REGULATE ITS MOTILITY. IMPORTANTLY, PRELIMINARY EVIDENCE WAS OBTAINED THAT TREATMENT OF FLOUNDER SPERM IN A TEST TUBE WITH TWO OF THESE SIGNALING MOLECULES, FORSKOLIN AND EPIDERMAL GROWTH FACTOR (EGF), ALONE FOR ONE MINUTE IS SUFFICIENT TO RAPIDLY INCREASE SPERM MOTILITY AND FERTILIZATION SUCCESS. THE POTENTIAL IDENTIFICATION OF A SPECIFIC MECHANISM CONTROLLING THE MOTILITY AND FERTILITY OF FISH SPERM SUGGESTS THAT IT MAY BE POSSIBLE TO DEVELOP PRACTICAL METHODS TO IMPROVE SPERM QUALITY IN MALE FLOUNDER BROODSTOCK BY TREATING SPERM WITH THESE SIGNALING MOLECULES. HOWEVER, IT IS NECESSARY TO FIRST IDENTIFY THE PRECISE SIGNALING PATHWAYS THAT CONTROL SPERM MOTILITY IN FLOUNDER AND CONFIRM THE EFFECTIVENESS OF THESE SIGNALING MOLECULES IN INCREASING MOTILITY AND FERTILITY. IN ADDITION, IT IS IMPORTANT TO DETERMINE WHEN FLOUNDER SPERM ARE RESPONSIVE TO FORSKOLIN AND EGF DURING THE REPRODUCTIVE CYCLE IN ORDER DEVELOP RELIABLE METHODS TO INCREASE FERTILIZATION SUCCESS. SPERM WILL BE COLLECTED FROM CAPTIVE BROODSTOCK AND SPERM MOTILITY IN RESPONSE TO FORSKOLIN, EGF, AND OTHER SIGNALING PATHWAY MOLECULES WILL BE EXAMINED UNDER A MICROSCOPE AND RECORDED. SPERM FERTILITY WILL BE ASSESSED AFTER THE SAME TREATMENTS WITH EGGS OBTAINED BY ARTIFICIAL (STRIP) SPAWNING DURING DIFFERENT STAGES OF THE REPRODUCTIVE SEASON. IT IS PREDICTED THAT THE RESULTS WILL CONFIRM OUR PRELIMINARY FINDINGS THAT ACUTE FORSKOLIN AND EGF TREATMENTS OF FLOUNDER SPERM ARE RELIABLE, COST-EFFECTIVE METHODS TO ENHANCE SPERM MOTILITY AND FERTILITY. THUS, THE RESULTS OF THESE STUDIES ARE EXPECTED TO PROVIDE THE BACKGROUND FOR DEVELOPING PRACTICAL PROCEDURES TO ENHANCE SPERM MOTILITY AND FERTILITY IN SOUTHERN FLOUNDER BROODSTOCK.