Assessing Monkeyface Prickleback Cebidichthys Violaceus as an Emerging Aquaculture Species in California

Assessing monkeyface prickleback Cebidichthys violaceus as an emerging aquaculture species in California by Matthew Hoehn Master of Science (Marine Science) in Moss Landing Marine Labs California State University Monterey Bay, 2023 In the context of global seafood demand and the pressing need for sustainable aquaculture practices, identifying and developing new species for aquaculture is of paramount importance. This study provides a comprehensive analysis of the reproductive behavior and embryological development of the monkeyface prickleback (Cebidichthys violaceus), an emerging aquaculture species in California. The species exhibits several desirable traits for aquaculture, including herbivory, sedentary behavior, high tolerance to environmental extremes, high fillet-to-carcass ratios, and product similarity to high-value, less sustainable fishes such as unagi. Since very little reproductive behavior was available at the start of these studies the experiments were designed on a broad basis. This research therefore intends to give a general description of the reproductive behavior of the monkeyface prickleback. This study employed geometric morphometrics, visual assessment, and ultrasound techniques to identify sexual dimorphisms, optimizing broodstock management. This study’s results revealed significant differences in head shape (Procrustes ANOVA, F46,4508 = 25.76, p-value < 0.0001) and supraorbital crest shapes (Procrustes ANOVA, F30,2940 = 5.96, p-value < 0.001) and eye placements between sexes (Procrustes ANOVA, F8,392 = 49.04, p-value < 0.0001), with ultrasound proving 96.7% accurate for sex identification. For all landmarks sex influenced shape change (ANCOVA, sex: F1,95 =344.53, p value <2.2e-16) and the interaction between length and sex influenced shape change (ANCOVA length:sex F1,94=24.26 p value <3.59e-6). For all supraorbital landmarks length and sex influenced shape change (ANCOVA length F1,95 = 22.85 pvalue = 6.37e-6; sex F1,95 = 89.34 p value =2.45e-15) and the interaction between length and sex influenced shape change (ANCOVA length:sex F1,94 = 12.36 p value =0.00067). For eye landmarks, length and sex influenced shape change (ANCOVA sex F1,95 = 89.34, p value = 2.45e-15; length F1,95 = 9.33 p value =0.003) and the interaction between length and sex influenced shape change (ANCOVA length:sex F1,94 = 17.78 p value = 5.69e-5). I also observed and documented the species' first-ever captive instances of fertilization depositing between 96,000 – 134,000 eggs. These eggs were characterized by an adhesive chorion that stuck eggs to each other. Characterization of embryology, hatching, and larval development were documented. Another important finding related the reproductive behavior was the discovery of the males’ role in guarding eggs. For the first time, we characterized crucial embryological landmarks. Other major milestones included size at hatching (7.43 mm), and time at first feeding (1 DPH). Endogenous resource utilization was also described by tracking the consumption of yolk and oil globule during embryonic development. More research is needed to optimize hatchery techniques and larviculture, which would significantly contribute to the development of monkeyface pricklebacks as a viable aquaculture species. This study not only enhances our understanding of the species' reproductive behavior but also offers new research avenues crucial for successful captive breeding programs and sustainable aquaculture development.