By Scott Bryan, Water Quality and Biology Administrator
Due to relatively high flows, a lack of cover and habitat, and sparse food resources, the CAP system is not an ideal location for fish to thrive. Despite this, fish populations in the canal persist at a reasonably high rate. Sportfish species, like largemouth and smallmouth bass, bluegill, redear sunfish, and striped bass enter as eggs or larvae at Lake Havasu and Lake Pleasant, grow into adults, and can be found throughout the system. Common carp, also from our source waters, thrive in the CAP. And grass carp and channel catfish are stocked annually for vegetation and insect control.
So, what happens when we drain sections of the canal for maintenance work; where do these fish go? Typically, fish will detect movement of equipment and people and move out of busy work areas. But in situations where we dewater a section of the system, CAP crews step in to rescue any resident fish prior to work beginning.
Once rescued, the fish are transported immediately — typically with a fish hauling tank — to the canal just upstream or downstream of the dewatered section.
Moving the fish is the right thing to do, but there are also other reasons:
- It is a requirement of the Operating Agreement between Central Arizona Water Conservation District (CAWCD) and the Bureau of Reclamation.
- The fish stocked for vegetation and insect control represent a relatively large expense to CAP so saving the fish also saves money.
- It’s a safety issue! If they aren’t removed, the fish – dead or alive — can pose a danger to employees for a variety of reasons, such as creating slipping and tripping hazards, emitting toxic compounds, attracting flies and other nuisance insects, and potentially attracting aggressive wildlife.
- These rescues allow us to evaluate and inventory the fish species assemblages in various sections of the canal, ensuring we meet our requirement to document any “new” species of fish found in the canal.
Saving fish – one at a time!