Kirby chief executive David Grzebinski sees pressure for consolidation mounting in the US tank barge market. Another quarter or two of pain could prompt more dealmaking. 

Grzebinski made the remarks during the company's second quarter conference call. The largest US-based owner of tank barges reported earnings that were in line with analysts' estimates. 

The Jones Act tank barge fleet grew rapidly over the last few years thanks to the US shale boom.