Did you know that...? (taken from the WWF's Ocean Facts site)
The global fishing fleet is 2.5x larger than what the oceans can sustainably produce.
75% of the world's fisheries are classified as "fully" or "over-exploited".
At least 25% of all fish caught is by-catch.
Annually, 30 million metric tons of this by-catch is being thrown over the side of fishing boats, dead or dying.
I'm not an expert, so I can only offer you my small collection of links about the subject
Fishing for Problems (and Compliments)
The SeafoodWatch Program of the Monterrey Bay Aquarium offers an excellent website with information about the status of many fish and seafood, the issues of the different ways seafood is obtained, and much more. It doesn't require any special expertise to read.
Fishonline, from the Marine Conservation Society, is a very compact website with plenty of information about fishing methods, a very useful glossary, and background info on fish stocks, maps of fishing areas, etc.
The Australian Marine Conservation Society offers information on fishing issues. The info on fishing gear may not be as accessible as the SeafoodWatch's but it is very exhaustive.
The WWF provides a lot of information in a very nice format in their Ocean Facts site. In their Sustainable Fisheries site you can find information on anything from the problems of Aquaculture to the Market-oriented solution of buying good seafood.
Auf Deutsch gibt es auch was: WWF-Schweiz. Das Meer bald leer? Nicht wenn auch Sie mithelfen!.
Auch vom Fisch-Informationszentrum gibt es ein wenig Info über Bestandserhaltende Fischerei, und andere Fischwirtschaftliche Daten & Fakten.
The International Council for the Exploration of the Sea (ICES) has the latest news on fishing affairs, among a lot more on the state of the Oceans.
The Fisheries Department of the Food and Agriculture Organization of the UN (FAO) offers a great deal of information, for those who want to read on fishing issues and some ways in which the world is dealing with them at depth.
OneFish is a Community Knowledge Directory which serves as an internet portal to all kind of information on fisheries. It has websites, documents, reviews and resumes. Incredible exhaustive!
People who (also) care about fish
Several organizations around the world have different programmes concerning the problems and recovery of the Sea. Get informed about the issues, and about other ways to collaborate.
The World Wide Fund (WWF) offers several ways to help, from active participation to simply going shopping. It has offices all around the world (info on their webpage).
The Marine Conservation Society, an UK organization for the protection of marine environments.
The SeafoodWatch Program of the Monterrey Bay Aquarium (US) offers several ways of participating.
The Marine Stewardship Council. You can help via donations or buying merchandise.
The High Seas Task Force. The Task Force is a group of fisheries ministers and international NGOs working together to develop an action plan designed to combat illegal, unregulated and unreported (IUU) fishing on the high seas.
Stichting De Nordzee is a Dutch NGO which focuses on marine life. They issued De Goede Visgids a guidebook for buying good seafood.