Changes to the base game
The biggest change in the base game is that the name has switched from "Settlers of Catan" to just "Catan". They've also updated the art (citation).
Changes to seafarers
Many of the scenario maps are different. It seems they used the maps from the 2008 German printing of seafarers when making 5th edition. The big change is that ...
You cannot buy commodities using fish.
If you discard 3 fish, you may draw one card from the hand of one of your opponents (Resource or Commodity Card).
If you discard 4 fish, you may take resource card but not a commodity.
The following applies also for the ...
When it says you will receive only 1 resource for the city, it is talking about the initial resources that you start the game with, NOT the resources produced by the city whenever the adjacent numbers are rolled.
From the rules under Setup:
Set up as outlined in the Catan base Settlers game, except that your second settlement is replaced by a city. You ...
In terms of Settlers expansion combinations, the catan official website really is a one-stop-shop. They have a combination listing for Seafarers and Fishermen, here. It says a few things about fishing and ships, but not about the pirate blocking fishing spots. Based on that alone, I'd say the pirate does not block fishing.
If that doesn't do it for you, ...
http://www.catan.com/service/combinations/fishermen-catan-rivers-catan says "If you pay 6 fish, you can build a bridge".
Meanwhile, the rules for the Rivers of Catan scenario specifically state that you cannot use the "Road Building" development card to build a bridge, and that would seem to extend to any combination of expansions/scenarios that replaces ...
According to the World of Catan Wiki:
Edit: According to this base game photo and this expansion photo from BoardGameGeek:
Base game (Total 30 tokens):
29 Fish tokens:
1 "Old Shoe" token
Expansion (Total 14 tokens):
14 Fish tokens:
5 settlements 5VP
4 cities =8 VP
Longest Road = 2VP
Metropolis = +2VP (above the city it's on) (3 of them).
2 1VP progress cards
6 Defender of Catan VP's as well.
There is a progress card that allows removal of an opponent's knight. Time it for just before the barbarians, and make him pull one, then you get your VP for Defender of Catan.
One clarification of the rules regards moving ships. In the 4th edition Seafarers Rulebook, there was a poor translation which made some people think that you could not ever move the ship that is closest to a homeport (i.e. you could never divorce a settlement and its first ship).
The 4th edition rules stated:
"You may only move the ship that is at the end ...
In the original scenario named The Fishermen of Catan, there was no limit to how many fish tokens could be kept. A revised version was published in Traders & Barbarians. This version included the following rule:
7 fish tokens at most: You are not allowed to have more than 7 fish tokens at any one time. If you already have 7 fish tokens and would ...