請問First ports of call 的意思

a port of call
圖片參考：http://hk.yimg.com/i/icon/16/6.gif

a place where you stop for a short time, especially on a journey. Our first port of call was the delightful town of Bruges
http://idioms.thefreedictionary.com/Port+Of+Call

請問First ports of call 的意思 !
上下文是 Items marked with* are considered suitable as first ports of call, while others are more complex, or relate to specific issues.

這應該是一條貨船的Schedule, 通知客戶:
有*記號的是指定停泊的港口(ports), 其它的港口要看情況而定.