Description and quantification of mortality in finfish marine aquaculture in Northern Vietnam

Principal Investigator: Larry Hammell, Jeff Davidson & Annette Boerlage
Co-Investigators: Phan Thi Van, Nguyen Viet Khue, Dang Thi Lua & Bui Ngoc Thanh

Although Vietnam is one of the most productive aquaculture countries in the world, marine aquaculture represents only about 1.7% of the overall farmed food fish production in Vietnam. The sector produces fish primarily for local consumption, and is targeted for further development by the Vietnamese government, but fish mortality is one of the main constraints for industry growth. Most farms are small-scale and culture several species simultaneously, and few farmers keep records of mortalities or other production information. While mortality events and their causes are not part of any formal records, total survival of less than 30% is often considered routine.

We investigated mortality-related production variables in marine finfish aquaculture in North Vietnam, using a questionnaire, and asked farmers to record daily mortality for one year. The primary objective of this study was to describe and quantify patterns of mortality in marine fish aquaculture in North Vietnam.

Farms averaged 9 years at their current location and had on average 24 cages per farm. Farms cultured multiple species, the most common being red drum, grouper, snapper, Asian sea bass, cobia, and pompano. Most farmers indicated that mortality between stocking and harvesting was between 50 and 75% for all species, but for some farmers it was more than 75% for some species, which is very high for finfish aquaculture. We observed high variation between farms and between cages within farms, indicating that mortality is an important consideration for productivity outcomes.