So, you want to show off your fish... Here is how to do it in two easy steps.

One day this month I was leading 25 students on a "Wildlands Water Walk" on our campus. At the end of the walk, it came time to take them all over to the Deppe Pond dam and share with them about the Mohave tui chub refuge here on campus. At the dam I usually explain to the students that helping endangered species is considered a beneficial use of water. It just so happened that this time, the well was turned on and water was flowing into the pond near the dam. With my back to the water, I was telling the students that the MTC can be hard to see at midday so they may not be able to see them when a chorus of students starting pointing and shrieking, saying, "There they are!" Turning around to face the pond, I half expected to see a school of mosquito fish, but to my surprise I saw a school of chub enjoying the cool plume of incoming well water as it mixed with the warmer pond water.So, if you want to show off your chub:

• Step 1, turn the pump on,
• Step 2, stand on the dam and wait for about 5 minutes, and the chub will come a-swimming.

Fish don't swim backwards very well...

When working with Mohave tui chub my students and I have noticed that they are attracted to cooler water being fed into a pond of relatively warmer water. Since this species of chub does not swim very well "upstream" against a fairly swift current, if the current of the incoming water is significantly swift, say 50 gallons/min (gpm) coming out of a two inch pipe, the chub will hang back in the plume of cool water. After the flow is stopped, however, by turing off the pump to a well, the fish enjoying the plume of cool water will procede to swim up that plume into the two inch pipe in mass, getting themselves stuck in the process. Thus the title of this article, "Fish Don't Swim Backwards Very Well". If you want to know the rest of the story, leave a comment and an email. Good Day!

Mojave tui chub: Hybridization and Invasion, April 2009 Science Newsletter, Mojave Preserve

Last April, the Mojave Preserve (NPS) published the first edition of their "Science Newsletter". In that publication there is a great article entitled, "Mohave tui chub: Hybridization and Invasion". You can find this article on page 4. A good read for anyone that wants to stay up-to-date on what is currently being discovered about the chub, its environment, and what is being done to help downlist this species from its current "endangered species" status.

What can you do when your pond shows evidence of eutrophication?

During the 2006-2007 school year, before Deppe Pond had a aerator installed a red water fern, most likely a member of the Azolla sp. (possiblly Azolla ruba), would take over the surface of the pond during the spring and fall months. This would generally follow our efforts to remove emergent species such as cattail and bulrush which stirred up sediments. After the pond was drained, dried, refilled, and an aerator was installed during the spring of 2007-2008, the azolla "blooms" disappeared but green filamentous algae began to grow along the bottom and raise to the surface as trapped gasses made it more buoyant. I believe both "blooms" were due to the eutrophication of the pond (its sediments and water). One element that did change between 2006-2007 azolla bloom and the 2007-2008 alga bloom, besides adding aeration in the spring of 2008, was the water source. Before the spring of 2008, Deppe Pond was filled by either urban runoff or with city water. After April 2008, only well water was used. I believe this fact begs that we test the water quality of the well water. More about that later.

It is our contention that fertilizer used on the lawn surfaces adjacent and uphill of Deppe Pond is the major nutrients that seem to be encouraging the increase in algae growth after the Spring on 2008. Plans will be put into place to decrease the application rates of fertilizer (if not stopping that practice altogether) of the “upstream” lawn surfaces. In the meantime the students and I have decided that we can possibly reverse the eutrophication process by harvesting the algal mats (and the nutrients they contain) that collect on the surface of the pond every month and compost the detritus at the greenhouse. Initial, we would rake and pitchfork what we could collect from the side. That proved to be a rather laborious process. So I tasked 4 students to design a tool that we could use both in Deppe Pond and in Tui Slough. The result worked beautifully.

It had to float and be sturdy, so we used closed–ended PVC. It need to be no wider that the narrowest point across Tui Slough, so it is 15 ½ feet long. It needed to be pulled from both sides, so there is a fixed center pull line. The line we used needed to be able to reach across the widest part of Deppe Pond, so the lines are 100 feet long. We needed to have anchored guidelines, so the ends of the 15 ½ foot PVC span have four foot guides, making it look like a wide capital H or I-------------------I, with a pair eye hooks to run two 100 foot anchor lines through. The last addition was a wire mesh (edging used to reinforce dry walled corners in homes) that was zip-tied along the length of the 15 ½ foot cross bar. This mesh provided the needed grabbing ability that our “algae-raker” would need. As you can tell from this slideshow, the device worked wonderfully. The best part of the whole process, however, was all the team work that went into its design (Thanks to Jeff Freed and Ethan Sockwell) and the teamwork that is needed to use our new "scum-raker" (the rest of the Mojave River Conservation class). (Patent Pending :^) ).