Massive Cockle Death in the Netherlands Leads to Uncertain Future for the Industry

Frozen Cockle

Portugal

Published Nov 7, 2019

Cockles in the Netherlands have died on a massive scale due to heatwaves during 2018 and 2019. The Netherlands is the third-largest exporter of cockles in Europe, but the future for exporters looks grim.

Cockle Fisheries in the Netherlands

The Netherlands is the biggest cockle producing country in Europe and the third-largest exporter of the clam on the continent. In 2018, the Netherlands exported around 23.2 million USD worth of cockles and other clams, mainly to other European countries such as Spain and the UK. Dutch cockles live in the Waddensea, a sea near the northern islands, and in the Oosterschelde river in the South of the country.

Cockles are a key species in the Netherlands: they both provide high economic value to fisheries, as well as providing huge ecological value to key bird species, such as the Eurasian Oystercatcher. To prevent disruption of the ecosystem, it is not permitted to fish for cockles using mechanical fishing techniques, as mechanical cockle fishing severely damages the cockle population. To ensure the sustainability of cockle fishing, only manual techniques are allowed, such as using a rake with a net attached. There are strict quotas as well: only 2.5% of the total cockle population can be caught per year. This makes sure there a plenty of cockles left for breeding and for species that feed on cockles.

High Cockle Mortality in the Waddensea in 2018 and 2019

As cockles are very susceptible to extreme weather conditions, they used to thrive in the moderate climate of the Waddensea. However, the Netherlands saw extremely hot summers in 2018 and 2019, causing mass cockle mortality. Cockles die quickly when exposed to temperatures higher than 30 degrees, which happened frequently during the summers of 2018 and 2019. As almost all cockles in the Waddensea live in shallow waters, around 60% of the cockles died during the heatwave during the summer of 2018. The summer of 2019 was even hotter and although official numbers are not published yet, fishermen estimate that 70-80% of the cockles died due to the extreme heat, the highest mortality rate since 1980.

The high cockle mortality leads to problems for the Dutch cockle fisheries. In so-called “cockle rich” years, cockle fishermen are allowed to freely fish only in certain areas, where the clams are abundant. In areas where the cockle population is vital for other species, only 3 ships are allowed to fish per specific area. However, in “cockle poor” years, only 2 ships are allowed in these areas and as the catch quotum is 2.5%, the total catch in 2019 is expected to be very low.

Future for Dutch Cockle Fisheries Looks Grim

After the massive cockle death in 2018, ecologists and fishermen were still hopeful, as 2018 was the most recent cockle breeding period. Cockles only breed every 6-8 years and spring 2018 was the first breeding period in 7 years. As cockle young are very strong and vital, most of the cockles developed during this breeding period were able to survive the 2018 heatwave relatively well.

However, the massive heatwave in 2019 has severely diminished the young cockle population, as the young cockles had become more vulnerable to heat due to aging. This means that it will take another 5-6 years before the cockle population in the Waddensea will increase again. Researchers expect that the Dutch Waddensea cockle population will diminish rapidly in the long run if the clam cannot adapt to the new weather conditions. This would mean serious trouble for Dutch cockle fisheries, as they are dependent on the Waddensea population for most of their catch.

As the Netherlands is the major cockle exporter to European countries, many European buyers will have to look for new sourcing destinations. China is the biggest exporter of cockles globally, accounting for over 50% of global exports, but does not export much to the EU due to distance. In Europe, the UK, Portugal, and Turkey are other major suppliers of cockles. Especially Turkey and Portugal are experiencing rapid export growth, providing an alternative to the Dutch cockle supply.