Chapters 3.14
3.14 Tresus Nuttallii and Tresus Campax
Cian Hudder, University of Guelph, Canada
https://inaturalist.ala.org.au/photos/21507652
Suggested citation for this chapter.
Hudder,C. (2022) Fish And Freshwater/Marine Invertebrates. In The Student Encyclopedia of Canadian Indigenous Foods. Editor, M.N. Raizada, University of Guelph, Canada. http://www.firstnationsfoods.org/
Introduction
When the inevitable mass extinction event occurs, there will be few more valuable resources than livestock and crops. This is true in all major power struggles : if you cannot feed your people, you cannot control them . Good thing there’s an animal that toes the line between livestock and crop; so much so that the areas in which they are farmed are called gardens. commonly called the clam; (Tresus nattallii) and (Tresus campax ). A sedentary, high protein, filter feeder is possibly one of the more logical choices on which to base in this possible future; improving water quality as well as providing dietary necessities to your faithful subjects. This paper will examine the creatures known as clams, specifically fat and pacific gapers native to North America, as well as the economic, cultural, and environmental viability of clam farming.
History of Evolution
Clams are bivalves, meaning they have two shells, or one shell split by a hinge; depending on how one looks at it. This characteristic evolved from animals with one shell, monoplacophorans (Carter, 2000). The evolutionary advantage is clear : protection frompredators. The trade-off is, of course, mobility. Interestingly enough, it seems like a good trade, as there are very few monoplacophoran extant species compared to the wealth of bivalve molluscs roaming around the seafloor. Since monoplacophorans aren’t exactly the cheetahs of the sea anyways , it would make sense to select for more specialized defensive traits rather than try and re-spec into speed so to speak; sort of a sunk cost deal . These shells are made of calcium carbonate in order to keep out predatory animals such as different types of bird, ray, crab, and even other molluscs (Kobayashi, 2006).
Another interesting adaptation is the self-burying that clams engage in. While much of marine prey life hides to protect themselves, the clam does this in a unique and curious way. By burrowing down beneath the sand, it provides not only cover, but their shell stays intact much better (Gosling 2003). This plays into their traits better, as gapers couldn’t move very much to begin with; hiding in corals, or living symbiotically attached to a much larger species just are not viable options. Here we begin to see the similarities to crops: you bury them underground, feed and water them, and dig them up when they are mature and ready to be eaten; sort of like a cucumber crossed with a sea cucumber.
Clams are far closer to the creature we were before we walked on land than they are to us. In fact we’re in completely different phylums, us being part of the Chordates as opposed to the Molluscs. This means we share some very rudimentary systems, although theirs has evolved quite differently than ours. They have a circulatory system, except they have one more chamber in their heart and it soaks all the organs in blood (Dorit, 1991). See Figure 1. for clam anatomy. heir digestive system is also quite different, featuring a unique organ found only in bivalves called the celia; which functions similar to a tongue, breaking up algae for digestion.
Geography of Domestication
Unsurprisingly, they first farmed in the areas theyare native toon the shores of North America.Fat gapers are generally found in the northern parts of the West coast, from California to Alaska, whereas Pacific gapers are found in the Southcontinent from California down to Baja California Sur in Mexico. These are generalities and the two do share habitat,Alaska and find a pacific gaper maxing and/or relaxing next to a fat gaper. Perhaps most famously, there are clam gardens around 3500 years old found in British Columbia (Toniello, 2019). Characterized by a wall made of large stones set back to the water line when the tide is lowest, these gardens would have been used by the Laich-Kwil-Tach and Coast Salish tribes and others (Citation needed).
you should be looking in estuaries; underground about a foot and a half. Estuaries are the points where the ocean meets a river, and the parts you often find gaper clams are in the intertidal zones, where, like the name implies, the high tide will cover the area, and the low tide reveals it(citation). The tide plays an important part in breeding for clams, as well as movement when they are in their larval stage (Loosanoff, 1963). Since they feed on algae which grows abundant in the mixed salt and freshwater of the estuaries, also referred to as brackish water, this is the ideal place for clams to reside.
Reasons For Domestication
When you think about species ripe for domestication, you generally want something willing to submit, something nonthreatening, and something that provides nutrition. Luckily for us, clams don’t have a brain, and are somewhat smaller than us. This means first and foremost two out of three of our conditions have been met; and the third will be discussed in the next section. The poor things don’t even have the capacity to realize they’re being farmed, and you would be hard pressed to find someone hurt by a misbehaving clam. The decentralized nervous system does provide some advantage over a centralized one like in us; it doesn’t require nearly as much energy. This is good news for farmers, as less energy means less food and less production cost. ultimately, clam shells have been used as an aesthetic for millenia; put on necklaces or traded west to east .
Nutrition
As humans get more and more sedentary, something that gets a lot more attention now than in the past is diet. How many flavour of the month diets have come and gone? The key is to good health is to eat a little bit of everything, all in moderation; but what can clams provide for us nutritionally? Faye Dong pondered this same question an. She showed that clams have a very low percentage of calories accounted for by fat; especially compared to beef or pork, favoured proteins in North America? Who is audience. They have nearly half of the cholesterol as pork as well at around 36 mg/100 g; this makes it suitable for low-cholesterol diets. Low fat, low cholesterol, what does it provide for us ? Around 14 mg/100 g of protein, as well as large amounts of omega-3 fatty acids, iron, copper, and vitamin B-12 (Dong, 2001). Clams would be a welcome addition to almost any diet.
It’s important to note that clams are not safe to eat raw. They could contain bacteria known as vibrio which can cause vomiting, diarrhea, and fever. To avoid this, clams must reach an internal temperature of 145 degrees give unit C or F to kill off this harmful bacteria (Washington State Dept. Health, 2018). Another biotoxin is Norovirus, but thankfully this can also be eliminated by thorough cooking. Unfortunately, like raw fish, people often ignore this and eat them raw anyways. When we do cook them however, it tends to be in the form of steamed clams. Their shells are washed first, as they are often left on while the clam cooks and even for plating; especially if cooking them in a sauce. They are often used in Spanish cuisine with spaghetti or in paella.
Other Uses
Aside from a phenomenal health food, what can the inedible parts be used for? Native Americans have a strong and well known history of using the whole animal; does this translate to clams as well? The shell of the clam is inedible, but it is made of calcium, an important nutrient for many plants. This means that clam shells can be reused as a fertilizer , raising the pH of your soil, and providing crucial micronutrients for plants (Citation to show there is evidence that they can be used this way). Although it won’t provide the same flavour as other seafood or chicken would, you can make a stock with clam shells; mostly in tandem with other bones or shells. Lastly, since clam shells are made of calcium, by mixing them crushed up with a slurry of flour and water you can make chalk. The Wsanec people, based just north of Victoria, BC often use clams as burnt offerings, as well as to hold burnt offerings. They also use them to produce rattles, digging tools, and blades; making sure the name of the animal is mentioned to give thanks to it (Olsen, 2019). These names are “SWÁÁM” or “SDEMYAAK ” if the neck is white. Sadly, this wide array of uses is often forgone in favour of the convenience of the garbage can.
Environmental Sustainability
When examining sustainability of livestock, some important questions to consider are as follows: what value does this creature add to their ecosystem? On what variables does this value depend? Would an excess of this value have negative repercussions on these variables, and how would these variables change? What are the effects of these variables changing on the rest of the ecosystem
Clams are filter feeders, in an aquatic ecosystem. This means that they clean the water while they feed themselves. In addition that they need nutrients in the water to spark algae and plankton growth in order to thrive. We talk a lot about nutrient runoff, an increasing problem in the Great Lakes region. This can be combated by filter feeders, allowing for this excess nitrogen in the water to be put to use (Long Island Sound Study, 2021). Less algae in the water means more oxygen for fish and sunlight for underwater plants, leading to increased biodiversity and a more balanced ecosystem. Rearing gapers would provide both a product and a service for us. Clam aquaculture is clearly a sustainable practice that requires little to no environmental inputs.
Unfortunately, when there is a large culture of zooplankton that feeds on this algae, vibrio parahaemolyticus multiplies rapidly, and finds its way into the local shellfish population (CFIA, 2020). This indicates that cleaning the water like this has some downsides, but as I mentioned before, this bacteria can be rendered ineffective by cooking. From a classical utilitarian perspective, this negative utility is counterbalanced, and surpassed by the positive utility of clam growth to increase biodiversity and clean our waters. Furthermore, the more filter feeders we import, the less zooplankton can be around to multiply this virus, and we could flatten the curve so to speak; so this virus would only be found in unusually high rates for as long as the zooplankton population was out of control.
References
1.Carter, J ., Campbell, D,. & Campbell, M. (2000). Cladistic perspectives on early bivalve evolution. Geological Society, London, Special Publications, volume 177. https://www.lyellcollection.org/doi/abs/10.1144/gsl.sp.2000.177.01.04
2.Canadian Food Inspection Agency [CFIA]. (2020). Measures to control the risk of Vibrio parahaemolyticus (Vp) in live oysters. Retrieved from: https://inspection.canada.ca/preventive-controls/fish/vibrio-parahaemolyticus/eng/1515442366959/1515442400440
3.Dong, F. (2001). The nutritional nalue of shellfish. University of Washington. https://wsg.washington.edu/wordpress/wp-content/uploads/publications/Nutritional-Value-of-Shellfish.pdf
4.Walker, D., & Barnes, ? initial. (1991). Zoology. Saunders College Publishing. https://openlibrary.org/books/OL1889253M/Zoology
5.Food and Agriculture Organization of the United Nations. (2004). hatchery culture of bivalves: a practical manual. FAO Fisheries Technical Paper, volume 471 https://www.fao.org/3/y5720e/y5720e00.htm#Contents
6.Gosling, E. (2003). Bivalve molluscs, biology, ecology and culture. Fishing News Books. https://vdoc.pub/download/bivalve-molluscs-biology-ecology-and-culture-25l7u6gugok0
7.Kai, Z. (2006). Chalk Prepared From Shell Powder. Google Patents. https://patents.google.com/patent/CN1923924A/en
8.Kobayashi, I. & Samata, T. (2006). Bivalve Shell Structure and Organic Matrix. Materials Science and Engineering: C. https://www.sciencedirect.com/science/article/pii/S092849310500353X
9.Lindberg, D. (2001). Biodiversity, Origin of. Encyclopedia of Biodiversity, volume 1 https://www.researchgate.net/publication/236733568_Encyclopedia_of_biodiversity
10.Long Island Sound Study. (2021). Ecosystem targets and target indicators https://longislandsoundstudy.net/our-vision-and-plan/liss-ecosystem-targets-and-supporting-indicators/
11.Loosanoff, V,. & Davis, H. (1963). Rearing of Bivalve Molluscs. Advances in Marine Biology vol.1.
12.Olsen, J. (2019). Wsanec clam garden restoration project final report. Retrieved from: https://wsanec.com/wp-content/uploads/2020/03/Clam-Garden-Report.pdf
13.Toniello, G,. Lepofsky, D,. Lertzman-Lepofsky, G,. Salomon, A,. & Rowell, K. (2019). 11,500 y of human–clam relationships provide long-term context for intertidal management in the Salish Sea, British Columbia. Proceedings of the National Academy of Sciences. https://www.researchgate.net/publication/336558148_11500_y_of_human-clam_relationships_provide_long-term_context_for_intertidal_management_in_the_Salish_Sea_British_Columbia#pf2
14.Washington State Department of Health. (2018). Vibriosis in shellfish. Community & Environment. https://doh.wa.gov/community-and-environment/shellfish/recreational-shellfish/illnesses/vibriosis#:~:text=Vibrio%20is%20destroyed%20by%20cooking,shellfish%2C%20especially%20in%20summer%20months.