Share prices in the London-listed aquaculture health and genetics group Benchmark Holdings tumbled 22 percent drop in the beginning of the week, following the company's reporting of a weak trading update.

The share-drop led to a market capitalization fall of £67 million (€72.2 million/$80.8 million), from £290 million (€312.5 million/$349.7 million) at market close on Friday, to £223 million (€240.3 million/$268.9 million) following the announcement on Monday.

Benchmark share prices plummeted over 22 percent on Monday. Photo: Bloomberg Markets

The London-listed company said challenging conditions across its operations in shrimp, seabass and seabream markets would result in lower sales and profits in the third quarter and full year, sending a negative message to the markets.

In July, Norwegian salmon giant SalMar's owner Gustav Witzoe snapped 11.47 percent of the company through his holding company Kverva off fund manager Neil Woodford.

As the London Stock Exchange market opened on Monday, share prices in Benchmark dropped to £0.41 (€0.44/$0.49), a 22 percent decrease compared to market close on Friday. The share price dropped another 1.2 percent with the stock market opening on Tuesday.