20.7.2026

Cecilia Damström: Raakku

Cecilia Damström: Raakku

huilu, oboe, klarinetti, käyrätorvi ja fagotti

11′

Orsino Ensemble:
Adam Walker, huilu
Nicholas Daniel, oboe
Matthew Hunt, klarinetti
Amy Harman, fagotti
Alec Frank-Gemmill, käyrätorvi

20.7.2026 klo 15 Kuhmo-talo, Kuhmo

Tilaaja: Kuhmon kamarimusiikki

The freshwater pearl mussel, in Finnish raakku, is a small but remarkable creature: it is a freshwater mollusc and one of Europe’s longest-living animals, capable of reaching an age of up to 280 years. Its shell, dark brown to black, rests quietly upon the bed of flowing, clear, lime-poor waters. Exceptionally sensitive to its surroundings, it has been legally protected since 1955. A single mussel may filter up to fifty litres of water each day, and is therefore regarded as an essential link in the functioning of aquatic ecosystems.

Once it reaches maturity—typically at fifteen to twenty years of age—the freshwater pearl mussel reproduces in summer. The males release their sperm into the water, which the females breathe in, thereby fertilising their eggs. A single female may carry as many as three to five million eggs. These develop within her gills into larvae, known as glochidia, which are released into the water between July and September (opening of the piece). Of these countless larvae, only one in a hundred million will survive to become a mature mussel.

Measuring merely 0.05–0.07 millimetres, the larvae resemble tiny mussels, though their shells remain slightly open until they encounter a suitable host. Once attached, they clamp onto the gills of a host fish and feed upon its bloodstream. Only salmon, trout, or the introduced American brook trout serve as viable hosts, meaning that the mussel can reproduce only in waters inhabited by these species. The fish itself does not suffer; on the contrary, the relationship appears to strengthen its immune system. In turn, the mobility of the fish allows the mussel to disperse to new habitats, even upstream.

Without a host, the larvae can survive for approximately six days in clear water, but in waters with high iron content, their survival may be reduced to a mere six hours. Within the gills of their host, the larvae remain for two to twelve months, depending on temperature: growth proceeds more slowly in colder waters.

Eventually, they develop into juvenile mussels measuring approximately 0.2–0.4 millimetres. The following spring or summer, they detach from their host and settle on the riverbed. Although relatively little is known about this stage of their life, it is believed that they burrow into sandy substrates, where they may remain for one to seven years. During this period, the majority perish. Only once they reach a size of around one centimetre do they emerge.

Having reached maturity at fifteen to twenty years, they remain capable of reproduction for the rest of their lives. The average lifespan is approximately 120 years, though exceptional individuals have lived far longer: one specimen found in Sweden reached 282 years, while the oldest recorded in Finland was 208 years old.

The freshwater pearl mussel came to the attention in Finland following an ecological disaster in Suomussalmi in 2024. A forestry machine operated by Stora Enso crossed a river inhabited by these mussels approximately 400 times, despite explicit prohibition. Around 4,000 mussels are believed to have died, while the remaining 7,000 had to be relocated to clearer waters, as the species cannot tolerate breathing murky waters caused by such disturbance. One mussel is valued at 583€, meaning that the company paid approximately €2.3 million in compensation, in addition to fines and the cost of restoration work.

In Finland, the freshwater pearl mussel is found in roughly 150 water streams (according to 2023 data), but reproduces successfully in only around twenty of them. Dams that prevent salmon from migrating upstream, thereby depriving the mussel of its essential host species, along with elevated iron levels and general water pollution, severely hinder both its reproduction and survival.

The freshwater pearl mussel dates back to the Cretaceous period and has existed for some 80 million years. Yet today, it is in decline—largely as a consequence of human activity. It is classified as a keystone species, meaning that its presence is vital to the survival of many other organisms. It also serves as a sensitive indicator of water quality: if only old individuals remain in a river, it signals that ecological conditions have deteriorated.

Raakku, opus 96, is my first wind quintet and is a commissioned work by the Kuhmo Chamber Music Festival 2026 and will be premiered by the Orsino Ensemble.