Study on the spread of nematode larvae in fishes marketed in Bulgaria

Abstract

The study on the spread of visible nematode larvae in frozen and fresh ocean and sea fish, marked in Bulgaria, has been conducted during the period 2017-2020. A total of 222 whole fish with head and offal (132 – frozen and 90 – fresh) were collected. The analyses were performed in accordance with Regulation (EC) 2074/2005. Presence of visible nematode larvae with sizes from 3 to 11 mm was found mainly on the walls of the abdominal cavity and the black membrane (94 %) and less frequently on the genitals (3 %). In the frozen fish was found only dead nematode larvae, but in the fresh fishes – alive. The prevalence of nematodes reaches to 100 % and the intensity of invasion varied from 1 to 25 larvae in the mackerel. In the case of fresh sprat, the extension invasion was in the range of 13 to 100 % and the intension invasion from 1 to 58 larvae. In the sample from hake, the prevalence of nematode larvae was 40-100 % and the intensity of the invasion – from 1 to 16 larvae. 50 % of the horse mackerel was infected with 1 to 6 parasites. The highest degree of intensity was found in fresh sprat, where the number of nematode larvae reaches 58. The health standards for fishery products, introduced by Regulation (EC) No 853/2004 do not allow infected fish with visible parasites to be marketed in the Community. The presence of live nematodes in fish creates a potential health risk to public health.