Fish farm escapes linked to overworked employees

One day in April 2013, fish farmers in Norway were trying to rid their farmed salmon of lice. As part of the treatment, the workers moved the fish to a new net cage. There was just one problem: the net hadn’t been properly placed, and the fish could swim freely into the sea. About 13,000 salmon escaped.

That incident was just one of many fish farm escapes in Norway over the last decade. The farmed fish — usually Atlantic salmon or trout — are born in hatcheries, moved by boat to net cages off the coast, and returned to shore to be killed. But raising and transporting thousands of fish is no easy task, and complicated procedures sometimes go awry. Once the farmed fish escape into the ocean, they could transmit diseases to wild fish and pollute their gene pool.

To evaluate the causes, a research team interviewed 12 people who had worked at fish farms, boat companies, or harvesting plants that had been linked to escapes. The researchers also pored through 33 non-compliance reports from the companies. And they attended a two-day workshop with aquaculture and trade association representatives about how to prevent fish farm escapes.

Several problems became clear. First, current aquaculture technology makes it hard for employees to see or prevent tears in the nets. For example, farmers often operate large cranes that can strain the nets, and rips may not be obvious underwater. Lice treatments also involve lifting heavy nets or tarpaulins with cranes, and “[f]ish farmers say they do not always feel in control,” the study authors write in Marine Policy.

Fish farmers must contend with stormy weather, wind, high waves, and darkness as they conduct their duties offshore. Bad weather can wear down the nets and make inspections more difficult. And workers often put in long hours, pressured to keep up the farm’s output. Here’s one description of overworked employees who failed to notice a tear in a net, which led to an escape:

During lice treatments workers had been working for several hours without proper rest. Due to illness they were understaffed and felt exhausted, but everyone was still determined to get the work done. However, following the operation, inspections of all net cages were not performed properly. Consequently, the tear was not discovered until later, allowing the fish to escape. Following the incident, the workers involved felt devastated.

The aquaculture industry needs to develop reliable technology that is easy to use and can withstand harsh weather conditions, the authors say. And while companies should do their best to prevent escapes, the workers shouldn’t be pressured into putting the fish’s safety before their own. “It is important that fish farmers truly feel that they can put personal safety first,” the researchers write. Roberta Kwok | 12 February 2015

Source: Thorvaldsen, T., I.M. Holmen, and H.K. Moe. 2015. The escape of fish from Norwegian fish farms: Causes, risks and the influence of organisational aspects. Marine Policy doi: 10.1016/j.marpol.2015.01.008.

Image © Strahil Dimitrov | Shutterstock

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