Critical Reasoning (CR) | Re: Sportfishers introduced the Zander, a type of perch, to Britain’s rive

Sportfishers introduced the Zander, a type of perch, to Britain’s rivers and canals in the 1970s. Because zander eat large numbers of smaller fish, they have had a devastating effect on native fish populations. To protect the native fish, a government program removed a significant proportion of the zander from Britain’s waterways last year. Surprisingly, this year the loss of native fish to zander has been greater than before.

Which of the following, if true, would most help to explain the