Sea urchin barrens and can stretch over 1000's of kilometers and last decades at a time. They are characterized by a predominance of urchins and coralline algae where kelp forests once existed. In contrast to barrens kelp forests provide habitat supporting thousands of vertebrates, invertebrates and plant species. Because kelp forests are keystone hosts their presence is vital to sustaining commercial and recreational industries including fishing and tourism. However, these kelp forests can collapse and shift to alternate stable states whereby urchin barrens persist. Over the last 4 decades, transitions between kelp beds and sea urchin barrens have been widely reported along temperate coastlines globally. During a kelp forest phase, urchin predation is the primary mechanism keeping sea urchin populations in check. However, due to various factors including climate change, predator densities can be reduced leading to shifts toward urchin barrens. Development of urchin fisheries has been implicated several times in recent history as a driver to return urchin barrens to kelp forests. However, this driver most recently has not worked in California where a large barren is currently persisting. California presently has an urchin fishery but it has been uneconomical for the fishery to operate given urchins in the barrens had little gonad development or undesirable human consumption traits necessary for commercialization . Aquaculture in the US has potential to restore kelp forests by collaborating with fisheries to harvest wild urchins from barrens and fatten them in an aquaculture setting prior to sale . This is of particular interest in California given U. S fisheries and environmental groups have long opposed aquaculture development due to concern of competition and environmental damage respectively . A collaboration between aquaculture and fisheries to positively impact the environment via urchin barren restoration would help to develop aquaculture in the US and California. Although urchin ranching operations exist there are still technical limitations to the activity, primarily being availability of macroalgae diets given seasonality and the propensity of urchin barrens to deplete kelp forests. Development of sustainable alternative diets for urchins is necessary for future commercial urchin aquaculture. In this student lead study a preliminary replicated diet trial was performed for ranching purple sea urchins (Strongylocentrotus purpuratus) collected from California barrens using 4 diet treatments including giant kelp (Macrocystis pyrifera ), ogo (Gracilaria pacifica), formulated commercial diet (Urchinomics) and an unfed control. During the 10 week study duration gonadal somatic index (GSI) was measured in a subset of urchins from each replicate tank every 2 weeks. Baseline GSI at the beginning of the trial was <0.5%. A GSI of 10% was reached most rapidly in the formulated diet treatment at 6 weeks, followed by ogo and kelp at 8 and 17 weeks respectively. This study was a preliminary examination of the feasibility of urchin ranching in California, showing biological potential for alternative diets to develop urchin gonads with a view to restore kelp forests and develop a nascent aquaculture industry in California.