The common mora, Mora moro (Risso, 1810) (Gadiformes, Moridae), is a cosmopolitan bathypelagic species of moderate commercial interest. Its usual bathymetric distribution in the western Mediterranean ranges between 800 and 1,500 m and in the Catalan Sea, M. moro is one of the main contributors to biomass at depths of 1,000-1,400 m. Although a number of studies exist on M. moro bathymetric distribution and depth-related trends, information on its parasites, diet and histological characteristics is very scarce and to the best of our knowledge no data exist on its parasite communities. A total of 62 specimens of M. moro were collected in 2010-2011 using a bottom trawl in two seasons and three localities of the Balearic Sea (NW Mediterranean Sea) at depths between 1,000 and 1,400 m. Parasitological, dietary (to prey-species level), enzymatic indicators of stress and histological data were obtained, alongside with environmental information (T, S, O2). The relationships among fish parasite load, condition indices, diet, enzymatic activity of muscular acetylcholinesterase (AChE) and lactate dehydrogenase (LDH), intensity of splenic melano-macrophage centres (MMC) and hepatic granulomas were tested. Detailed relationships were found between parasite taxa and prey ingested (e.g. Anisakidae gen. sp. related with meso-bathypelagic crustaceans; Anisakis Type I with benthopelagic squids), increasing our understanding of the parasites life cycles. Most parasites were linked to samples with highest levels of near-bottom O2, which enhances higher zooplankton biomass, higher food availability for M. moro and, likely, higher parasite infection via prey ingestion. Total parasite abundance and the abundance of Tetraphyllidea fam. gen. sp. showed a significant relationship with the activity of AChE and the abundance of Anisakis Type II with LDH activity. These results could suggest that fish with reduced stress levels, as suggested by enzymatic markers, host more abundant and diverse parasite communities. AChE correlated with hepatosomatic index (HSI) and condition factor (K); and LDH activity with gonadosomatic index (GSI), K and fish total length (TL). LDH activity showed differences among sampling groups. Parasite load was not associated with the intensity of splenic melano-macrophage centres (MMC) and hepatic granulomas suggesting that, in the present study, the degree of parasitation does not have a negative impact in fish health

XVIII Simposio Ibérico de Estudios de Biología Marina (SIEBM), 2-5 september 2014, Gijón.-- XVIII Simposio Ibérico de Estudos de Biologia Marinha (SIEBM).-- 1 page

This study was supported by the MICYT projects “ANTROMARE” (CTM2009-12214-C02-02-MAR, CTM2009-12214-C02-01-MAR)

Peer Reviewed