Palaemon serratus (Pennant, 1777) and its cumbersome parasite: The impact of Bopyrus squillarum (Latreille, 1802) on the shrimp’s reproductive output and fishery.

Francesco Golin

The Palaemon serratus’ fishery in Ireland is important but vulnerable. Shrimp populations are heavily reliant on recruitment, and exploitation causes very high mortality rates. There is a lack of knowledge about the processes that control shrimp population size. Together with the relative lack of management measures put in place and the variable nature of national landings, the sustainability of the fishery is uncertain. Bopyrus squillarum, an isopod parasite castrates the shrimp, potentially impacting recruitment within populations. This parasite also creates a bulge that could promote retainment of the shrimp in traps and incorrect classification of smaller shrimp in more expensive grades. On top of that, the weight of the parasite could increase the total weight, and hence price, of the catch. The work outlined here found that B. squillarum can particularly impact recruitment through infections of larger female shrimp, while no effect of the parasite on shrimp retainment was found. The parasite led to a 5% increase in the annual cost of shrimp. From the results obtained here it is clear that the parasite affects the shrimp fishery and more information is needed to better understand these impacts, as well as the contribution of broader environmental factors.