Freshwater pearl mussels are among Europe's most endangered invertebrates, with captive breeding programmes attempting to supplement declining wild populations in clean, salmon-bearing rivers.
Pearl mussels are filter feeders sensitive to siltation, nutrient enrichment, and temperature increase. Mass mortality events from pollution or drought expose mussels to thermal stress and food deprivation. Captive breeding requires careful maintenance of temperature, water chemistry, and fish host availability. Mussel sentience remains uncertain, but precautionary welfare consideration is warranted given evidence of nociceptive responses in bivalves. Wild mussels in eutrophied rivers experience progressive habitat degradation without immediate mortality but with long-term fitness decline.