RESTOCKING THE ZRMANJA RIVER

The Zrmanja is one of the most beautiful rivers in Croatia and indeed in all of Europe. Its canyons, waterfalls, and crystal-clear waters have shaped life in Bukovica for centuries. The river sustained people, brought communities together, and served as the natural backbone of this region. Yet in recent decades, the Zrmanja—along with the people who once lived beside it—has nearly fallen silent. The devastation of war, economic collapse, and prolonged emigration have emptied the villages along its banks. As people disappeared, many of the activities that once kept the river alive gradually vanished as well.

It was from this realization that the restocking project was born, initiated by the Sportsko-ribolovno društvo Natura and the Fondacija Bukovica. The idea is simple yet powerful: to restore life in the river so that life along the river may gradually return. Restocking with native fish species is the first step toward protecting the river ecosystem, developing sustainable fishing tourism, and, in the long term, revitalizing the local economy.

The secret of the fish that bears the river’s name

During the project’s preparation, we discovered something especially inspiring: the Zrmanja is home to an endemic species of trout—the Adriatic, or Zrmanja trout—which even carries the river’s name in its Latin designation: Salmo zrmanjaensis. Its olive-green body, marked with distinctive red spots, is a hallmark of this unique river ecosystem. This fish has been part of the Zrmanja’s natural identity for centuries—dating back to the time before the last Ice Age.

However, in recent decades, this species has nearly disappeared from the river. Years of illegal fishing, along with the lack of systematic care for the river ecosystem, have led to a dramatic decline in its population. The restoration of this native species has therefore become the central idea of our project.

A project that captured public attention

Even the announcement of the first restocking with this species sparked remarkable public interest. We planned an event by the Zrmanja that was meant to be more than just a restocking effort—it was envisioned as a meeting point of science, culture, and the local community. Television crews announced their arrival, and media interest exceeded our expectations. Messages of support poured in via social media from across Croatia and the diaspora. Many asked how they could help and take part in the restoration of the Zrmanja.

The project has also attracted, through media coverage, the attention of leading scientific and professional institutions: Velebit Nature Park, the Ruđer Bošković Institute, the Faculty of Science, University of Zagreb, and the Ministry of Agriculture, Forestry and Fisheries of Croatia.

The delay that transformed the project

Yet this very interest brought to light an important and previously overlooked question: is the fish sold on the market under the name “Adriatic trout” truly the original species, or merely a marketing label concealing something entirely different?

On the eve of the planned restocking, we received a notice from the Ministry of Agriculture, Forestry and Fisheries of Croatia requesting that the action be postponed until a genetic analysis could precisely determine the species in question. Although the decision was difficult, we chose to act responsibly and suspend the project.

The genetic analysis took far longer than expected. Instead of a few weeks, we waited for months. When the results finally arrived, they revealed that the fish purchased as Adriatic trout was in fact brown trout—a species very similar in appearance, yet genetically distinct. Had we released it into the Zrmanja, we would have jeopardized the genetic purity and survival of the native Zrmanja trout. Even the delay itself attracted significant media attention.

A new and far greater goal

Although initially a setback, we soon realized that the project had gained a much more important dimension. At a joint meeting of SRD Natura, National Park Velebit, and the Fondacija Bukovica, a decision was made to launch a project to breed genetically verified Adriatic trout right by the Zrmanja River. In the future, such fish would be used for restocking.

According to Ivana Buj of the Faculty of Science in Zagreb, who specializes in trout research, such a careful and responsible approach to preserving a native species has not previously been recorded in Croatia and could serve as a model for similar initiatives.

A project that outgrew its original scope

In recent months, various possibilities have been explored to identify the most suitable location and method for breeding the native Zrmanja trout. This is a long-term and demanding process that goes beyond the initial scope of our project and the capacities of our foundation. Nevertheless, the Fondacija Bukovica will continue to play an active role in this effort and seek ways to support it.

What began as a one-day restocking initiative has grown into something far greater: a movement to preserve one of the Zrmanja’s most valuable native species and to restore a river that is an integral part of the natural and cultural heritage of Bukovica. And where life returns to a river, so too returns the hope that, one day, life will return to its banks.