When the Hook Catches More Than Fish: Protected Species at Risk from Lost and Active Fishing Gear

Although the impacts of fishing gear on wildlife have received increasing scientific attention in recent years, freshwater ecosystems have been studied far less extensively than marine environments. To produce the first comprehensive inventory in Hungary of wildlife groups potentially at conservation risk from lost or actively used angling equipment, researchers led by the Wetland Ecology Research Group at the HUN-REN Centre for Ecological Research conducted a media analysis spanning four decades. The findings were recently published in the international journal Scientific Reports.

“As ecologists or nature enthusiasts, we occasionally encounter animals that have become trapped, injured or even killed by fishing gear. However, collecting data on affected wildlife is challenging, as dedicated field studies on this topic are particularly difficult to design and carry out. Fortunately, several recent studies have shown that by systematically reviewing content uploaded to social media and other online platforms, researchers can compile valuable datasets with relatively little effort, including information on the impacts of lost and actively used fishing gear on aquatic environments and wildlife,” said Dr Viktor Löki, who initiated the study.

As part of the project, the researchers carried out a nationwide investigation based on four media platforms. Between 1984 and 2024, they documented 200 cases in which fishing gear interacted with animals other than fish. For each case, they recorded the species involved, the number of individuals affected and, where possible, the location of the incident.

“Our analysis revealed that at least 64 animal species in Hungary have demonstrably been affected by unintended entaglement involving either lost or actively used fishing gear. Birds were the group most frequently affected, followed by reptiles, while all other animal groups combined accounted for just over 10% of cases. The mute swan (Cygnus olor) was the most frequently recorded victim, with 32 incidents. Among reptiles, the European pond turtle (Emys orbicularis) was most often affected, appearing in 18 cases, typically after ingesting bait pellets attached to hooks. Of the 226 individuals recorded overall, more than 70% belonged to species protected under Hungarian law.

To place these findings in an international context, Gunasekaran and colleagues documented only 90 cases involving 144 trapped or dead individuals from 35 species across the whole of India in a similar media analysis published in 2024. As their study focused on the conservation risks posed by lost fishing gear, our research highlights that the conservation impacts of angling equipment should not be underestimated, even in a country much smaller than India,” summarised Dr Viktor Löki.

The vast majority of incidents involved just two types of equipment: fishing lines and hooks. Lost fishing gear accounted for most cases, although actively used tackle was responsible for a comparable number of incidents. The habitat type could be identified in 132 cases. Detailed analysis showed that bycatch incidents were recorded more frequently in natural aquatic habitats than in artificial ones. Among the identified habitat types, affected animals were most commonly found along rivers, followed by natural lakes, angling lakes, artificial reservoirs and quarry lakes.

Mortality was recorded in fewer than 10% of affected individuals. Although this may appear to be a relatively low mortality rate, it is likely to underestimate the true impact. Observers probably freed many entangled animals, and no follow-up monitoring was conducted to determine whether they survived in the long term. In cases of bycatch that go undetected—particularly in remote or poorly monitored areas—survival rates are likely to be considerably lower. Furthermore, delayed mortality and non-lethal but harmful consequences, such as injuries, reduced mobility and increased vulnerability to predators, are not reflected in the available data.

“This topic clearly warrants further investigation. Most anglers have experienced similar incidents, yet these are not always documented, and even when records do exist, they are rarely available online. While seeking images to illustrate the study, I contacted one of the anglers featured in a newspaper report. He told me that a year after photographing the common goldeneye featured in the article, he caught another individual of the same species at the same location using a boilie bait. According to his account, several coots were caught in a similar manner during that year as well.

A logical next step for this research would therefore be an online questionnaire targeting anglers. By analysing their responses and any offline records they provide, we could gain a much clearer understanding of which members of Hungary’s wildlife, beyond fish, are exposed to this conservation risk and to what extent,” emphasised Dr Viktor Löki.