DAO 140:109-118 (2020)  -  DOI: https://doi.org/10.3354/dao03495

ABSTRACT: The Gulf of Maine northern shrimp Pandalus borealis population once supported a significant commercial winter fishery for the New England states. However, the fishery has been on moratorium since 2014 due to consecutive recruitment failures. The issue of parasite-infected eggs, so-called ‘white eggs,’ has long been identified for the Gulf of Maine northern shrimp, which makes shrimp eggs nonviable and subsequently hampers the recruitment potential. Furthermore, the proportion of infected females was observed to increase with water temperature. As Gulf of Maine temperatures have been increasing for decades, it is important to re-visit issues related to white eggs to evaluate possible impacts of climate-induced environmental changes on the white egg infection rates. We used biological samples collected by the Northeast Fisheries Science Center in 2012-2016 to evaluate the probability that a female shrimp was infected (P_inf) and the proportion of white eggs in an infected female shrimp ( p_we). Although P_inf was high, with an average of 73.81% over the Gulf of Maine, p_we was mostly <5%. The variation in both P_inf and p_we examined in this study was not well explained by environmental factors or female body size. However, the average rates of both P_inf and p_we observed in this study were higher than those observed in the 1960s when the bottom temperatures were cooler. The results can be used to account for egg mortality and provide information on potential impacts of possible climate-induced variability on shrimp population dynamics.

KEY WORDS: White eggs · Egg mortality · Northern shrimp · Pandalus borealis · Gulf of Maine · Climate change