Apart from Costa Rica's flora and fauna, on of the most abundant resources of the country is, well, aquatic resources.This why the country is also one of the best sites for charter fishing specially in the Tamarindo area. Blue Marlins, rooster fish, miho, barracudas, rooter fishes and tunas, are most popular on these regions. Some have been recorded to reach up to 20o lbs., and sometimes even larger than that.
More about this, on the link provided below.
Link: news Charter Fishing in Costa Rica