What We Do
Gone fishin'
At the PHS hatchery, we raise the endangered Razorback Suckers and release them back into the Colorado River. Every day, students and fish hatchery members feed the fish to help them grow, take water chemistry tests, clean the tanks and surrounding areas, and observe fish behaviors. Some additional jobs that students and hatchery members are involved with at the hatchery include weighing the fish, tagging them, and measuring them to track the growth of the fish over the time frame that they are being raised.
The Daily Activities of the Hatchery
The Filtration System
One of the main responsibilities of working in the hatchery is to make sure that the water quality for the fish is adequate on a daily basis. The system for which the water goes through to be recycled yet safe for the fish is shown to the left. First, the water is pulled from the tanks and into the sump tank, which is where all the fish feces is captured. From this, the water is filtered through a bioreactor biofilter, and then through two dual bag filters to catch large particles in the water, as well as a UV filter to disinfect the water of any diseases before being recirculated back into the fish tanks. For this system to keep running adequately, students are required to scrub and siphon tanks every other day to loosen debris on the side of the tanks and then be filtered and caught in the system. Additionally, as the bag filters catch this debris from the tanks, the filters need to be cleaned and changed out every two days as well. If the water clarity is in a worsened state than normal, a water change-out may be necessary. This is the only time that new water is put into the system, and this allows for better water clarity as the new water dilutes the turbid water, inevitably causing the water to become more clear.
Weighing the Fish
The PHS fish hatchery team measures the weight of the fish from each tank in samples of 10-15 fish from each tank at a time. This is done about 1 to 2 times per month and allows the amount of feed for each tank to be calculated based on the mass and growth rate of the fish, as well as being a way to count the fish in each tank. When students weigh the fish, it is important that the most amount of water is shaken or brushed off and out of the nets that transport the fish from the tanks to the bucket. Remove the most amount of water allows for a more accurate mass of the fish, as the water mass is canceled out on the scale prior to the fish being placed onto the scale.
Water Chemistry Tests
At least once a week, students check the water chemistry for the fish, making sure that nothing is becoming unbalanced. From left to right in the photo above, total alkalinity is a measurement of the concentration of all substances of alkaline dissolved in the water that attract and release Hydrogen bonds, as these interferences can cause changes in the pH of the water. Testing the Nitrates and Nitrites of the water in the tanks as high levels of nitrate can cause the fish's growth to be stunted, and through nitrifying bacteria, nitrite is turned into nitrate, as long-term exposure causes stress levels to rise.
PIT Tagging
Rounding Up the Fish
This process happens every time that the fish are being tagged, weighed, or measured. Although this may seem like an easy skill, it takes time to catch the entire tank. Students need to make to not move to quickly as this can cause the fish to become too stressed and possibly not eat as much as normal, inevitably stunting their growth. As the students catch the fish, they are dumped into a seperate net, until all fish are caught from the tank and put into that net, ready to be distributed.
The Fish Spa
Once the fish are netting as a whole, they can be divided into groups of 10-15 that are then placed in a separate tank of a mixture of clove oil and water, which is an experimental anesthetic that is being tested by the PHS hatchery for other mainstream hatcheries. Normally, the larger hatcheries would use a type of novocaine to put the fish to sleep in order for the tagging process to occur. Yet, a type of clove oil is being tested to be used instead as it is more natural, and based around the district guidelines, was administered as being safe for students to use. It takes approximately one minute for the fish to be knocked out enough for the tagging process to occur, and waken after about two minutes of being in the normal tank once again.
Inserting the PIT Tag
Now that the fish are knocked out from the clove oil, the fish are now docile enough to be handled by hand and placed on a board in preparation for injecting the PIT tag. PIT stands for Passive Integrated Transponders, and are tracking systems that do not require a source of power. Thus, once the fish are injected with the PIT tag using the needled tagging system (showcased on the left of the image above), and once the fish are released back into the river once sufficient grown for the year, the fish can be tracked by being exposed to a scanner, done quite often by Fish and Wildlife Services, as well when the fish cross fish ladders while traveling through the Colorado River.