July is crayfish season, but local crayfish are becoming rarer

July is traditionally the month when people in Latvia go crayfishing – catching crayfish in rivers and lakes. Crayfish have inhabited Latvian waters for thousands of years, but their numbers have been declining recently. The main reason is the introduction of invasive species that outcompete the native crayfish.

Researchers from the Institute of Food Safety, Animal Health and Environment BIOR – Edmunds Bērziņš, Haralds Plostiņš, and Roberts Strazdiņš – explained on the radio program "Zināmais nezināmajā" that invasive species have become established among local populations and threaten their survival. Although specific data on the spread of invasive crayfish are not provided, the researchers indicate the situation is concerning.

Native crayfish are sensitive to alien species, which are often hardier and reproduce more quickly. Therefore, crayfishing enthusiasts should be aware that catches may become rarer if measures to control invasive species are not taken. For now, there are no concrete solutions, but researchers urge attention to this problem.