Welcomme (1988) listed potential adverse impacts from unwise introductions: degradation or disruption of the receiving environment, predation, overcrowding and stunting, genetic degradation, introductions of disease, and socio-economic effects. Potential consequences from introduced nonindigenous fish species in the United States were summarized by Taylor et al. (1984) and include:
(1) habitat alterations from removal of vegetation by consumption, uprooting, or increased turbidity; degradation of water quality-siltation, substrate erosion, and eutrophication;
(2) introduction of parasites and diseases;
(3) trophic alterations from forage supplementation, competition for food, and predation;
(4) hybridization; and
(5) spatial alteration from aggressive effects and overcrowding. Stroud (1969) summarized an invitational, multiagency conference in Washington D.C. in February 1969 that dealt with exotic fish introductions and the related problems.
Except for a few species in isolated bodies of water (such as peacock cichlids (Cichla ocellaris), grass carp (Ctenopharyngodon idella), and blue tilapia (Tilapia aurea), little research has been conducted in Florida to measure the beneficial or detrimental consequences from the introductions of nonindigenous fishes on native flora or fauna.
