Final answer:
Fishermen often omit details such as the types of fishing gear used, the actual quantity of fish caught, and the precise locations where they fished from their catch survey forms.
Step-by-step explanation:
The information that fishermen left out of their catch survey forms most likely includes the types of fishing gear used, the actual quantity of fish caught, and potentially the locations where they fished. Fishermen often use broad methods like gillnetting or trawl netting, leading to large bycatches that are not always reported accurately. Furthermore, the mass of the fish is frequently underreported, as fishermen tend to give approximate weights rather than exact measurements. The economic value of these catches is considerable, with industrial and artisanal fisheries generating significant revenues. However, these figures can be higher than officially reported, as illegal, unreported, and undocumented (IUU) catches add to the overall catch numbers, a fact that is often overlooked in official reports.