Brown seaweeds (Fucales) produce phlorotannins that are often considered chemical defenses against herbivores. The many correlative and fewer direct tests conducted have shown effects of phlorotannins on herbivore feeding behavior to be variable. In an attempt to clarify the roles of phlorotannins versus other metabolites in defending brown algae, we conducted bioassay-guided fractionation of herbivore-deterrent extracts from the commonly studied brown alga Fucus vesiculosus. Feeding by the amphipods Ampithoe valida and A. longimana and the sea urchin Arbacia punctulata was suppressed by crude and water-soluble extracts of F. vesiculosus, but this deterrence was lost following storage or fractionation of the active, water-soluble extract. Phlorotannins in these extracts did not decompose in parallel with the loss of feeding deterrence. F. vesiculosus phlorotannins were fed to herbivores at 3 to 12 × the isolated yield (or 4.2 to 16.8% of plant dry mass). No herbivore was deterred from feeding by concentrations of 3 or 6 ×, but A. valida (the only test herbivore that readily consumes F. vesiculosus in the field) was deterred at 12 × isolated yield. When juvenile A. valida were raised on an artificial diet containing F. vesiculosus phlorotannins at 3 × isolated yield, the phlorotannin-rich diet significantly enhanced, rather than reduced, amphipod survivorship and growth relative to an equivalent diet without phlorotannins. Females ovulated only on the phlorotannin-rich diet. Compounds other than phlorotannins appear to defend the F. vesiculosus populations we investigated, but we were unable to identify these unstable compounds.

No abstract

The United States seafood industry is undergoing rapid change, as a result of the current trade war with China, ongoing global COVID-19 pandemic, and new governance mandates. The new Executive Order (EO) on Promoting American Seafood Competitiveness and Economic Growth, signed in May 2020, proposes wild-capture fisheries deregulation and prioritization of aquaculture (i.e., aquatic farming), with an emphasis on offshore development. Recent disruption of wild-caught seafood supply and demand could create space for sustainable aquaculture growth, but expansion could also undermine wild fisheries livelihoods and economics if integrated management between industries is ignored. Here, we review the current state of US seafood and outline five guiding principles to better manage US fisheries and aquaculture: (1) make precise and strategic fisheries reforms that continue to support sustainable wild fisheries, (2) integrate aquaculture and fisheries using an ecosystem-based approach, (3) address social resistance to aquaculture, (4) improve aquaculture data collection, and (5) reconcile nationalism in a global market. Implementation of these principles is critical for balancing social-ecological trade-offs amongst wild captured and farmed seafood systems, and for ensuring a more resilient US seafood sector under an anticipated future of increased volatility.

is the College Librarian for Engineering at Cal Poly San Luis Obispo. She has over 12 years of experience working in Engineering Libraries. Her research focuses on issues of diversity, equity, and inclusion in libraries.