。。
I'm expecting a decent haul, so do your best and bring back some fish, okay?
Literal
Decent [gen-の] fishing-results [obj-を] am-expecting [because-から]. Do-your-best fish-[come-and-てきて] [please-ちょうだい].
そこそこ 'reasonably / decently' is the casual adverb of mild approval. 釣果 'fishing results / catch' is a compact compound. 釣ってきて combines 釣る 'to catch (fish)' with ~てくる in its 'do X and come back' sense — 'catch and bring back.' ちょうだい is the softer, familiar imperative form of 'please' (from the honorific verb 頂戴する 'to receive'), often used by women or in casual family contexts.