Quote: " how is it possible to sustain growing world populations and consumption of fish without aquaculture (mariculture)"
It isn't! Fisheries is clearly in a complete mess (it most certainly is here in the UK where the legality of fishing goes back to the Magna Carta and much regulation is carried out by the archaic, underfunded Sea Fishers Committees who have to both police and promote fishing) and virtually all existing fisheries are over-exploited. Without wanting to be overly pessimistic, unless there is a fundamental shift in the power broker's thinking, then wild caught fish will become uneconomic and will force us into mariculture.
Mariculture in most of its current forms has substantial problems, as have been pointed out here already, and these mostly effect its of long term sustainability. Having dived under Salmon farms I can confirm that even in very exposed sites food gets through the nets and sits on the seabed, and I have invaribaly seen dead fish in the bottom of the nets too.
The only real, sustainable solution requires a highly responsible attitude on the part of governments, and a realisation that they need to sacrifice national requirements for a higher purpose. Viable National and International fishing methods and quotas need to be both determined and set and there needs to be a determination to police whatever regulation is needed. By doing so they could just produce a marine environment which could be sustainably fished and there should be little need for mariculture! The other point is that we cannot sustain ANY food production system with ever-growing world populations - absolutely obvious but often overlooked as it has implications which many find unacceptable.
I suggest lobbying your local politicians about fisheries as this is a good way to start them realising that there is a problem and then they may think that something needs to be done.