This is good. Plant based diets certainly would curtail the TEQ of dioxin and dioxinlike PCBs in fish. There is a great future for plant based diet in replacing fish meal at least to certain levels. The only problem is the reduced Omega 3 fatty acids. However the phosphorus problem is not going to major issue is mordern aquaculture goes the way of water recirculation farming system. However there are ANF in many plant feed sources. These ANF can affect the growth and life of the fish too. These can as well be taken of during preparation of by use of enzymes.
Good article about Vitamin Mix Gives Farmed Fish in aquaculture. Plant based vitamins are not sufficient to give the best results.
Though alternate feed source is a nice news but the drawback of Omega 3 missing in fish leads some losses of nutritional value as Omega 3 is a common source from fish after olive oil. However it must be researched on olive oil extract residue for fish food otherwise we only turn to get benefits from the mass of fish and not for the quality of fish as Omega 3 has critical impact of the cholesterol digestion so the fish consuming only on plant feed would lead to obesity in consumers of fish.