Query Ignoring 'zero' Catch Sets

I have a db with two tables linked by a Set_ID field. One table characterizes set information (date, time, location etc) and the other table has records for groups of fish caught in the set. The fish_table has (amongt others) a field for species (text), clip-status (yes/no), coded wire tag status (yes/no), and 'count' (number). The count field is necessary to allow input of groups of fish en-masse, or individually, depending on the amount of accessory information obtained.

Obviously, some sets catch no fish and so no record is entered into the fish table for those sets.

When I design a query, I want to produce a table that sums up the count field for each set, and produces subtotals for each species (and for the 4 variations of the clip/tag status fields).

My efforts so far are only partially succesful in that I can produce the correct subtotals, but only for sets where something was caught. Sets with no corresponding fish_table record are ignored instead of treated as zeroes.

Is it necessary to manually enter a 'zero' count for each species of interest for each set that we do? (Massively time consuming) Or is there some other way to query the db that forces the query to equate no fish record with a zero value?

Any thoughts? I've searched the forum, and googled, but haven't come across anything I could recognise as analogous to my dilema.