Vocabulary is everything

During our EDPROFST700 lecture yesterday we were talking about struggling students that can decode and read effectively, but when asked had little or no comprehension of what they read. This is particularly common trend among English as second language students. 
Today, my class were exploring recreational fishing rules. We were reading Fishing Rules and creating charts to show the minimum size and maximum quantity we are allowed to catch. As part of the activity students were asked to do some research of their own to add more types of kaimoana to the chart. One of my students who is fluent in Tongan, was researching the Snapper legal size limits.
After she read the first paragraph of the article  

"Snapper bag limits in the country's most popular fishery will be reduced from nine to seven, and the minimum legal size increased from 27cms to 30cms from April 1 next year."

I then asked her what the legal size for snapper is. She replied, about 27 - 30 centimetres. I asked her to read the last part of the sentence again, then asked, "what does 'increased' mean"? She didn't know. I took for granted that this was language that she would have, and as a result, could not comprehend the article. We then uncovered the vocabulary in the paragraph, and then she was able to understand that increase meant more, reduce meant less, or decrease.

This scenario really honed in for me the professional discussion we had yesterday and the need for explicit and implicit teaching of vocabulary.
Without understanding the vocabulary being read, it is no wonder that students cannot correctly comprehend, as a teacher it is important that I use and expose students to more and more vocabulary, but also that in this exposure I implicitly describe the meaning of what is being said. Assume nothing.