Fishery activities comprise fishing, aquaculture, and processing and marketing of fish and fishery products. According to the Standard Classification of Activities in the Republic of Slovenia, fisheries are divided into marine fisheries, freshwater fisheries, cultivation of marine organisms and freshwater aquaculture, and processing and preserving of fish, crustaceans and molluscs.

Fishery can be further subdivided into sea fishing, for commercial and non-commercial purposes, and inland fishing, which is non-commercial.

Aquaculture is cultivation of all aquatic organisms and involves the cultivation of freshwater as well as marine organisms (mariculture).

Processing and preserving are parts of the fisheries activities, which give fish and fisheries products value added and ensure quality consumer products. Slovenia only operates a few plants which specialize exclusively in the processing and marketing of marine and freshwater fish. The Administration of the Republic of Slovenia for Food Safety, Veterinary and Plant Protection lists 24 businesses involved in fishery products. The group consists mainly of small-sized entities, and one large-sized business. Marketing of fishery products is carried out by several registered establishments, i.e. fish farms, as well as a certain number of fishermen. Fisheries are important for the Slovenian market as it ensures that it is well supplied with high-quality fishery products.