While Zimbabwe and Zambia squabble over fishing rights in the world’s biggest dam, an invasion of Australian crayfish and Nile tilapia is threatening to wreak havoc with Lake Kariba’s indigenous species.
Built in the 1950s, the 280km- long reservoir hosts an industry that has more than 1 100 commercial boats that hunt shoals of 7cm-long Tanganyika sardines, known locally as kapenta, at night.
The boat fleet is more than double the recommended number on the lake, yet catches on the Zimbabwean side have plunged by more than half over the past two decades.
Under a 1999 agreement, Zimbabwe had the right to 55 percent of the boats on the lake, whose kapenta population could support 500 rigs, the Zimbabwe Parks and Wildlife Management Authority said in response to questions.
Zambia had 185 licensed boats in 2000, the UN Food and Agriculture Organisation said.
The kapenta, which are attracted using fluorescent lights then scooped up in round nets, are dried and sold in both countries as a cheap protein source.
Zambia now had 725 kapenta rigs on the lake, while Zimbabwe had 406, the Zimbabwe parks authority said.
“Nothing seems to be improving,” Chareka said as he surveyed the catch, flanked by five workmates. “There is no more kapenta to talk about here, there are too many boats, too much fishing not just on the Zimbabwean side, but even on the Zambian side.”
The total kapenta catch in Zimbabwe is forecast to fall to 8 500 tons this year from 8 746 tons last year, according to Zimbabwe Parks. That compared with a record catch of 19 957 tons in Zimbabwe in 1993 and a record combined catch of 28 843 tons that year, Madamombe said in the research paper.
Zambia is supposed to cut its number of rigs by 50 a year over the next decade while Zimbabwe will reduce its fleet by 13 a year, according to Zimbabwe Parks. The countries will conduct an acoustic survey later this year to assess the total population.
While both sides had too many boats, the Zimbabwean side was better regulated, said Kennedy Siabuwowa, a hotel worker in Zambia who quit kapenta fishing because of the low catches. “They have good controls for fishing,” he said from Siavonga, on the northern shore of Kariba. “They normally follow the rules.”