Marine scientist Portia Nillos Kleiven with a live lobster in her hands (Photo: Havforskningsinstituttet)

Strong increase in lobster fishing around protected area

NORWAY
Tuesday, January 22, 2019, 00:30 (GMT + 9)

The marine protected lobster area set in Tvedestrand, in the Sørlandet region, is showing very good results for lobsters recruitment and size, and, in theory, it should also provide a surplus for the surrounding areas.

Map by Tvedestrand Municipality.

The Institute of Marine Research (IMR) points out that the lobster reserve was created with the purpose of securing a greater number of lobsters, and larger, in the surrounding area, but this has led to an increase in fishing pressure in its surroundings.

“There has been a general increase in the intensity of lobster fishing, but we are also seeing a psychological impact caused by the reserve,” explains marine scientist Portia Nillos Kleiven.”

“As you would expect, the area surrounding the reserve to have improved as a fishing ground, more people want to fish there. The phenomenon is known as ‘fishing the line’," she added.

Since the creation of the lobster reserve in 2012, marine scientists have monitored the lobsters closely. Here Alf Ring Kleiven is doing experimental fishing in 2013. (Photo: Espen Bierud / Institute of Marine Research)

The scientist´s latest article published in the Proceedings of the Royal Society B: Biological Sciences, shows that the fishing pressure outside the reserve had doubled within four years of its creation.

Over that same period, it tripled along the boundaries of the reserve. Therefore, the net impact on the lobster population within 1.5 km of the boundaries was therefore negative.

“The reserve itself is beneficial to the lobsters that live there. Their number almost tripled over the same four-year period”, said Kleiven. “Just outside the boundary, we see a decline in the population, and the situation improves as you move further away from the reserve,” she explained.

The red line shows the experimental lobster catch from the centre of the reserve, where it is clearly greatest, outwards. The black line shows the catches before the reserve was established.

In her opinion, these results show the need for a plan for the areas surrounding the reserve, if it is to have a positive impact beyond its own limits.

“Empty habitats outside the boundary may attract lobsters from within the reserve. This may result in more lobsters being caught in the short term, but it will also negate the intended purpose of the reserve”, the scientist explained.

Kleiven and her colleagues measured the changes in fishing pressure in and around the MPA by counting the number of lobster traps in the area before and after the establishment of the lobster reserve. They counted up to 3,000 pots spread across 52 square kilometers.

Detailed map of the Tvedestrand coast showing the MPA (box with solid line), and the study area (dashed line). Grey lines indicate depth contours. Inset: map of northern Europe indicating approximate location of study area (red star). (Online version in colour.)

In 2017 it became mandatory to sign up to fish for lobsters, partly based on the IMR advice to the fisheries management.

“This will make it far easier to estimate catches and fishing pressure in the future. That puts us in a great position to learn more about how the authorities can optimise the design of lobster reserves,” Kleiven concluded.

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