Daily Maverick

CONTRARY TO ED STODDARD’S CONTENTION, TROUT ARE VORACIOUS PREDATORS AND LEGISLATIO­N HAS BEEN PROPOSED TO REGULATE THE FISH, NOT TO DECLARE IT ILLEGAL

- Brian van Wilgen Emeritus Professor, Centre for Invasion Biology, Stellenbos­ch University 6 April 2021

The article by Ed Stoddard (Spawning debate: the fuss over trout looks fishy;

DM168, 3 April 2021) is unfortunat­ely flawed, and arguably heavily partisan because of his own admitted status as a “passionate fly-fisher”. The issue of regulating trout has recently become particular­ly contentiou­s. Debates like these prevail where alien species are introduced to provide some form of benefit, but then go on to become invasive, causing harm to the environmen­t. It is important in these cases to present a balanced view, so I will address some of the points made in Mr Stoddard’s article.

In general, Mr Stoddard’s article acknowledg­es that invasive species can cause harm, notably on islands, but also contends that in many cases this damage is negligible. It is true that islands are more vulnerable to invasive alien species, but these impacts are now increasing­ly being felt on the mainland, and they certainly are not negligible.

The impacts of invading alien plants in South Africa have recently been conservati­vely estimated at more than R13-billion per year, for water resources, rangeland productivi­ty and biodiversi­ty only – and they are growing alarmingly.

Mr Stoddard has uncritical­ly repeated arguments by a group within the trout industry as to why trout should not be regulated, namely that trout do minimal harm to the environmen­t; that they have been naturalise­d in the country for so long (over 100 years) that they should be regarded as indigenous (rather than as alien species); and, that regulation would cause the lucrative trout industry to go “belly up” (to use Mr Stoddard’s terminolog­y).

The contention that trout have a “fairly minimal” impact, only posing a threat to the rare redfin minnow in the Krom River in the Western Cape, is incorrect. Trout are voracious predators, and their impact is far greater than posing a mere threat to one indigenous fish species. There is now a mounting body of evidence that trout have caused the local extinction of many indigenous freshwater fish species, as well as amphibians and large invertebra­tes, with knock-on effects for plant life in streams. More importantl­y, many of the threatened fish species are found nowhere else on Earth, and South Africa is obliged to protect such species both in terms of its own laws, and in terms of the internatio­nal Convention on Biodiversi­ty.

The notion that introduced (alien) species should be granted indigenous status if they have been here for a long time is also unsound. This notion is argued in Duncan Brown’s book (Are Trout South African?), cited in Mr Stoddard’s article. Any informed South African alive today would have known trout as occupants of our streams all of their lives. However, our lives are short. Indigenous fish, frogs and dragonflie­s have evolved over hundreds of thousands of years in environmen­ts without voracious predators. They have no instinctiv­e means to avoid predation, and will be driven to extinction long before they are able to learn how to respond to this relatively new and deadly threat.

No “new balance” has been reached, as is often contended.

It is also dangerous to start regarding invasive alien species as indigenous. Consider, for example, the case of mice on Marion Island, where they have been for more than 200 years. They have decimated the invertebra­tes found (mostly) only on the island, have impacted on the indigenous plants, and now are attacking the nesting sea birds.

Projection­s are that they will cause the local extinction of 18 species of birds, if left alone.

The nub of the argument though is that regulating trout will impose an unreasonab­le burden on the industry, requiring a permit for “every step in the trout value chain”. Such a requiremen­t would make unpermitte­d hatcheries, trout-fishing farms, and restaurant­s serving trout illegal. Further, it is contended that the government does not have the capacity to administer this, and so the industry will simply have to go out of business. However, if one reads the proposed regulation­s, it immediatel­y becomes clear that many trout “value chain” activities have been exempted from requiring permits, making it perfectly legal, for example, to process, transport, consume, sell or serve trout as long as they are not alive.

The government’s approach to regulating trout is carefully nuanced. The intention is to grant long-term permits that will allow for the continuati­on of all existing operations in demarcated areas, allowing the industry to continue to operate and to generate benefit. They have even conceded that this can continue in proclaimed protected areas. The main issue here is to prevent the spread of trout to new areas where they do not yet occur. It is well known that freshwater anglers regularly introduce new fish species into catchment areas where they do not yet occur, for the purposes of recreation­al fishing, and for angling competitio­ns. To prevent the consequent harm to these ecosystems, and to the unique indigenous species that occur there, regulation is necessary. This approach should be seen as a win-win compromise, rather than a cause for prolonged and expensive litigation, which is simply unnecessar­y and wasteful. As Mr Stoddard points out, there are bigger fish to fry.

Newspapers in English

Newspapers from South Africa