The 1993 collapse of the Lake Kinneret bleak fishery

Bleak, Acanthobrama terraesanctae Steinitz, constituted an important fishery in Lake Kinneret, Israel, accounting for ≈ 60% of the total commercial harvest, but less than 10% of the total fisheries income for the entire lake. The market demand of 900–1000 t annually has maintained relatively constant harvest pressure since the 1970s. The fishing season of 1992/93 was the last time bleak were harvested commercially. In 1993/94 the fishery collapsed; less than 10% of previous harvests was caught, and most fish were below commercial size. An overview of the bleak fishery during the past 60 years is presented, with evidence indicating that the collapse was the result of two interdependent events relating to harvest-induced stress: (i) a long-term shift in harvested fish size (age) that began in 1982; and (ii) two consecutive seasons of overharvest that led to the depletion of 2–3 year classes and the excessive recruitment of young-of-year of a single year class.