It was the 2002 return that crashed and in 2003 no adult salmon were raised in Broughton farms:
"In 2003, farms in the Broughton area were free of adult salmon during the outmigration period under the terms of the Broughton Archipelago Action Plan. In 2004, returns to the Wakeman River, Kingcome River, Ahta River, Kakweiken River, Ahnuhati River and Glendale Creek showed dramatic increases. A subsequent paper authored by, inter alia, Richard Beamish and Simon Jones, confirmed that
early marine survival of pink salmon had increased from 1-2% to 34% and attributed the increase to a combination of reduced lice pressure and increased nutrients, saying, “The processes responsible for the high marine survival cannot be identified with certainty, but they could include increased freshwater discharge in 2003, which may have resulted in lower salinity less favourable to sea louse production, increased inflow of nutrient-rich water to the study area, and the introduction of a Provincial Action Plan that required mandatory louse monitoring and established a fallowed migration corridor for pink salmon.”
https://www.livingoceans.org/media/news/amazing-pink-salmon-returns-and-salmon-farm-closures#:~:text=In%202003%2C%20farms%20in%20the,Glendale%20Creek%20showed%2Just to add. I have found the paper by Beamish and Jones mentioned above. They provide total pink salmon returns in the Broughton from 1990 through 2004.
Total returns in 2002 was 69,000, in 2003 187,000, 2004 912,000. Excluding 2004 (the year often described as the highest returns on record) In the 13 years (no returns were noted for 1999) total returns exceed 2004 6 times. The highest return on record was in 2000 at 3.461 million. I'd also note that of the years with higher returns than 2004 the lowest was 2001 at 1.36 million so 2004 was not an exceptional year though rather remarkable given how low the spawning escapement was in 2002.
I don't know where the frequent claim that 2002 was followed the highest return ever came from but that is clearly a false claim.