The tilapia of Lake Victoria is no longer what it used to be. In the last three decades it has grown smaller and nobody knows where this is going.
Local and Japanese researchers say the Nile tilapia, the most abundant and commercially important tilapiine in Lake Victoria is changing.
Today’s mature female tilapia is almost nine centimeters smaller than it was in the early 1980s. The researchers from University of Eldoret, Egerton University and Nagasaki University, Japan attribute the changes to overfishing.
The team in a study published recently indicates the fish could be experiencing more changes than just size.
“Nile tilapia in Lake Victoria, is faced with intensive fishing, especially the rampant use of small mesh gillnets causing a decrease in size and possibly changes in fish condition.”
The team had studied the size of the Nile tilapia for a two year period to 2015 and compared this with data collected since the 1980s.
While then the female tilapia at maturity measured 30-35 cm currently it is measuring about 26cm. The size of the male tilapia has not changed much remaining on average at 31cm.
The reduced size at maturity in female Nile tilapia, the researchers suggest may be a strategy to maximize reproductive success in response to overexploitation.
The authors suggest a limitation on net size to reduce pressure on maturing females. Now you know, next time you order tilapia ask for the male.