Spatial overlap of jellyfish and fishing resources in northern Patagonia, Argentina

SCHIARITI, A.; BETTI, P.; MORIONDO, P.; DATO, C.; DERISIO, C.; GENZANO, G.

Barcelona

Simposio; 5th International Jellyfish Bloom Symposium; 2016

Institut de Ciències del Mar - CSIC

The neritic environment in northern Patagonia (43-47°S, Argentina) is a productive, economically valuable ecosystem, supporting two of the most important Argentinean fishing resources (Argentinean hake Merluccius hubbsi, Patagonian shrimp Pleoticus muelleri). In this area, jellyfish are abundant during summer coinciding with the recruitment peak of these fishing resources. We measured the spatial overlap and co-occurrence of jellyfish and M. hubbsi and P. muelleri in Patagonia by analyzing the data set obtained in fishery surveys performed by the INIDEP each January from 2005 to 2014. We used spatial analyses tools to determine the species that have potential to affect the recruitment of these fishing resources and the areas in which these interactions are likely to occur. Significant spatial overlap occurred between the ctenophores Mnemiopsis leidyi and Pleurobrachia pileus and the Argentinean hake (eggs and larvae), although the results were highly variable amongst years. Only M. leidyi overlapped with the early stages of the Patagonian shrimp. Conversely, there was a negative relationship between the distribution of the 8 hydromedusa species and both fishing resources. This could be explained by the low frequency of occurrence and abundance of most hydromedusae except Aequorea forskalea s.l. In this case, although highly frequent and abundant, this species seems to occur in colder water masses. In locations overlap is high, predation by ctenophores on fish/shrimp eggs and larvae, and their preys, may be an important factor in the dynamics of commercially important species.