Blog Post: Will Mussel Aquaculture Be Viable Along The California Coast?


Priya Shukla

Mussels are found the world over. Many native freshwater mussels are admired for their ability to clean our streams and rivers, while invasive ones (which are actually clams masquerading as mussels!) are reviled for voraciously eating plankton and clogging pipes. The shells and tissues of mussels are often used as monitoring instruments because they reliably record changes in the surrounding environment.

musselsIn western North America, tightly packed conglomerations of the California mussel span from southwest Alaska to the end of Baja California. And, archaeological evidence indicates that the indigenous peoples of western North America consumed these mussels 13,000 years before moules-frites appeared on seafood restaurant menus in Pacific coast backwaters.

Although mussels have a rich tradition in European cuisine – going so far as to appear in Enlightenment-era art – oysters have reigned as the primary shellfish consumed throughout the United States, including in California. As demand for oysters grew and natural populations dwindled, the U.S. oyster industry transitioned from harvesting natural oyster beds to growing them in coastal waters (“aquaculture”). Oysters have been farmed in California since 1929, but mussels have been farmed in Europe since the 13th century. With global demands in seafood increasing, mussel farming – a $3 billion global industry – is now emerging along the California coast.

musselsAquaculture was responsible for nearly half of the seafood consumed in 2015, and farmed shellfish made up 10% of all seafood consumed that year. Mussels grow the most easily of all farmed shellfish, reaching market size within a year. They are incredibly nutritious; a single Blue Mussel contains only 290 calories, but has 40g of protein and 1,500mg of Omega-3 fatty acids. While these characteristics make mussels an ideal target for a profitable business and for securing food resources around the world, it is unclear how the changing climate will affect the success of these mussel farms.

California’s coastline is on the frontlines of climate change. San Diego saw its warmest ocean temperatures this past summer, a toxic algal bloom closed the San Francisco Bay Area Dungeness Crab industry in 2015, and oyster and abalone farms are actively combatting acidifying waters. Mussels, like oysters and abalone, build a protective calcium carbonate shell to protect their soft tissues from the elements. In more acidic waters, mussels – especially young ones – have a hard time building their shells and the protein-laden byssal threads (“beards”) that they use to secure themselves to the rocky shore degrade. They are also incredibly sensitive to rises in temperature.

beachFor my doctoral research at UC Davis, I plan to study how climate change will affect the mussel aquaculture industry. Because farmed mussels are often suspended on ropes using their byssal threads, I am interested in exploring whether warmer, more acidic waters will prevent mussels from staying attached to ropes and affect their overall production. Mussel aquaculture presents many opportunities in California and around the world, and I hope to use my research to make mussel farms an enduring and robust enterprise as the oceans continue to change.



Blog Post: Decisions, Decisions

Figure 1. The gloriousness that is Oreos. Look at that! Apple pie flavored Oreos. Truly we live in a magical time.
Figure 1. The gloriousness that is Oreos. Look at that! Apple pie flavored Oreos. Truly we live in a magical time.

Gabriel Ng

“There’s no such thing as a free lunch.” “You can’t have your cake and eat it too.” Tradeoffs: it’s an intuitive concept that we grasp and grapple with in our everyday lives. Any decision we make has some benefits but usually incurs some costs also. Do I buy this box of Oreos or use that cash to purchase some broccoli? (The answer is always Oreos). Do I go barhopping with friends or spend my time studying? The balance of costs and benefits are parameters we factor in every time we make a decision. And for the most part, these decisions are relatively easy. Rarely do we find ourselves paralyzed with indecision as we traverse about our daily routine. I’m not drooling off into space during breakfast as I decide whether I should use 3 tablespoons of coffee to ration my supply or 5 tablespoons to ensure I get my hit of caffeine.

Figure 2. This is my study snail, Tegula funebralis. It may not look like much, but it has a pretty intense fear response when it smells predator in the water. Here it is doing what it knows best, leaving the water when it is afraid.

However, there are times when the tradeoffs within a decision are tremendously complicated. Cost-benefit analyses only work when they are directly comparable, i.e. in the same units. Yet, most tradeoffs involve outcomes with differing values. How does one exactly evaluate the time spent with one’s offspring (I assume that’s a good thing. I don’t know. Kids are icky) versus the effort spent working overtime? You can’t compare apples and oranges because well… they are apples and oranges. Now, an economist might argue that we can distill decisions down to monetary value. A hedonist focuses on happiness units. Though we can try to reduce our decision outcomes to some common currency, we also lack perfect information. What are the opportunities we miss out on every time we make a choice, aka opportunity costs? There may not be a direct cost to milling around in bed watching Netflix during the weekend, but that time could have been spent finding the cure for cancer (or something equally as productive).                      

fear response
Figure 3. The fear response in Tegula funebralis is effective in escaping predation but it incurs the cost of unable to feed while out of water. So what’s the tradeoff if it doesn’t leave the water and instead continue to forage when a predator is around? I will leave the photo of a crab plus Tegula funebralis shell fragments as the answer (it was a massacre).

But why I am talking about human decision making in a marine science blog? I don’t study human behavior. I study something much more exciting: snails along the rocky intertidal. While these animals do not face the same tradeoffs that we do, they have their own suite of complicated decisions they must make everyday. How should it allocate its time feeding versus avoiding predatory crabs? Is it worth competing with another individual over a seaweed patch or better to find a lower quality patch with no competition? Like us, these snails face the same complications when considering tradeoffs except the stakes are literally life and death. What makes this system particularly interesting to study is that the optimal decision among the various tradeoffs has already been solved through millennia of evolution. And I want to know why that particular decision is the best given the current environment. Sure, my research may never allow me to figure out the optimal ratio of Oreos to broccoli I should buy (I have a hunch it’s all Oreos and no broccoli), but knowing why snails behave as they do can provide further insight on the inner workings of our intertidal coastline.