October 31, 2017
The potential uses for algae are numerous, from biofuels to medicine to a sustainable food source for humans. But algae innovations are also critical for important work in marine science and conservation. Most marine organisms start their life cycle eating algae, and for researchers trying to bring species back from the brink of extinction, a healthy diet from day one is a critical part of the process.
White Abalone (Haliotis sorenseni) is one of those species; prized for their flavorful meat, many abalone species were fished down to critical numbers. The white abalone population has been slow to recover and it is currently listed as one of NOAA’s Species in the Spotlight, an effort to highlight the most critically endangered species and the work being done to recover their populations. Dr Kristin Aquilino of the UC Davis Bodega Marine Lab is working to save the species, and shares how algae plays an important role in her quest.
Please describe your organization:
I direct the white abalone captive breeding program for UC Davis Bodega Marine Laboratory and NOAA. We are growing endangered white abalone in captivity with the goal to place them back out in the wild and save their species from extinction.
What species of algae do you work with?
We primarily work with Macrocystis pyrifera (giant kelp), Palmaria mollis (dulse), and Navicula sp. We are also just starting to use encrusting coralline algae.
Figure 1 Fresh dulse aglae ready to be fed to growing abalone
How did you decide to use those species?
Red abalone farmers, particularly Doug Bush at The Cultured Abalone Farm, have been instrumental in helping us identify the best algal diets for our abalone at each life stage.
Do you use different species of algae for different purposes?
We use macroalgae to optimize growth and reproductive condition among our adult white abalone. Our abalone love kelp – it’s like a Twinkie to them: delicious, but lacking the nutritional quality of other algal species. So, we feed them protein-rich dulse as well. They’re definitely not as into the dulse, but it helps improve their growth and reproductive condition. Kids must eat their health food, too!
Figure 2 Juvenile white abalone grazing on dulse
We use Navicula as a settlement cue and first diet for our newly-settled abalone. It’s the perfect size to fit into their tiny, newly-developed mouths. Even after we transition our 5- to 6-month-old abalone from their Navicula “baby food” to their macroalgal diet of dulse and giant kelp, we continue to occasionally feed Navicula through the first couple of years.
We are starting to experiment with using encrusting coralline algae as a settlement cue. Encrusting coralline algae acts like a natural landing pad for larval abalone in the wild, and we’re hoping it will help us improve captive production.
Figure 3 Newly settled baby white abalone grazing on halos algae
How do you get the algae?
We harvest giant kelp from the wild, usually by wading out during low tied. We maintain a culture dulse onsite. We purchase Navicula from Reed Mariculture. So far, we have either harvested encrusting coralline from the wild or gotten it to recruit onto substrate held in tanks in Southern California and transported it north to our lab. We are hopeful to try to start our own encrusting coralline culture.
Have you had any problems with algae cultivation/use in the past?
We have trouble collecting wild kelp in the wintertime, as it is in low abundance on the Northern California coast in the winter due to storms. We also tend to have lower dulse abundance during that time. It is very difficult to get encrusting coralline algae to grow in our systems, but we are collaborating with others at Bodega Marine Lab to try to find ways to optimize its growth.
It’s clear that a healthy wild population of algae, as well as advancements in lab-grown algae both contribute to this important work. Thanks to this collective effort, the captive breeding program has thousands of white abalone growing, which gives hope to restoring the wild population in the future. Learn more about Dr Aquilino’s and the Bodega Marine Lab’s efforts to save white abalone on her webpage.
Interview by Cannon Purdy