Interesting results lead to more questions… How light color effects redfish larvae

Hello everyone,

Our REU program may be coming to an end, but we are still running experiments over in the Fuiman lab at the Fisheries and Mariculture building. However, we have already found some very interesting trends in the survival and growth of the redfish larvae under our six different colored light treatments. To reiterate the project’s intentions, we are testing various LED light fixtures that all have different spectra to see if they are better than traditional fluorescent lights at raising up redfish through their first dietary transition from yolk to zooplankton. Our working hypothesis was that they would have better survival and growth than the control treatment (fluorescents) but what we are finding is actually quite interesting.

Redfish Larva ~13 days old

Redfish Larva ~13 days old

An analysis of our survival results has shown that the red-toned light treatment is the only one that has significantly higher survival than the  control Red spectrogramtreatment. With regards to growth, the green, blue, and violet treatments were all significantly  higher but they had very low survival. Our survival results are very interesting, because after paging  through some of the literature on fish visual abilities, one would find that most species of bony fish are  not even able to see red light. So what gives? We are still wrapping our heads around this finding, but  we are thinking that perhaps the fish cannot see the red wavelengths emitted by the red-toned fixture,  and are instead benefiting from the light’s low output in the other colors of the spectrum. We are also speculating that perhaps the fish can see in red and are possibly able to see their prey more easily due to higher contrast or fluorescence of the zooplankton.  We are running additional fluorescence tests this week, and the next set of experiments will be testing different intensities of light, so      perhaps the fish will do better in dimmer versions of all of the other treatments!

Our growth results also brought up more questions because, the way the blue and violet treatments were set up, they were identical to the white treatment, but we simply added in a monochromatic strip LED to supplement the spectrum. Because the blue and violet treatments had high growth rates, and the white treatment did not, this suggests that those specific wavelengths were benefiting our fish. However, the blue, violet, and white treatments all had low survival, so the benefits aren’t far reaching. Again, we speculate that perhaps the fish could see their prey easier under these conditions, and thus grew at a higher rate than the control.

Cypress

Me, feeding zooplankton to our tiny fish!

 

These results and much more will be in my presentation this Wednesday, and I am happy to have found some very fascinating relationships in this  project. I am also happy to have formed some great relationships in the REU program; working with the faculty and staff at FAML has been a true  learning experience for me. I feel like I am one step closer to making some of the most important decisions of my career as a marine scientist, and I  owe  it to the guidance and support of the people of UTMSI and FAML. I am so grateful for having the opportunity to enter the scientific community  early on as an undergraduate, I can only dream of what comes next!

 

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