MF Jeebhay et al. Occupational and Environmental Medicine. Sept (2001) Vol.58 #9 p 553.
A selective review of occupational seafood allergy.
In general seafood processing seems highly energetic and manually involved. This creates the potential for extensive skin contact with fish proteins and the production of respirable protein aerosols.
The author finds that most types of seafood have been found to cause occupational allergy: