LONG-TERM FLUCTUATION OF THE WATER QUALITY AND FISHERIES RESOURCES IN ISE BAY

Abstract

 Influences of nutrients on fisheries resources in Ise bay were reviewed. Concentlation of the total nitrogen and phosphorous were decreased after peaking in 1980s, In 2015 they were decrease below the environmental standard zone II for water quality (TN:0.3mg/L, TP:0.03mg/L). The chrolophile-a which provides an indication of food environment were also decreased especially in southern bay. The fatty and mature index of short neck clams in Ise bay were decreased with reducing of the chrorophyl-a, and low qualities of Porphyra yezoensis were increased with luck of the nutrient in southern part of Ise bay.