Great Ecology in the Great OutdoorsSeptember 29, 2016
All the Pretty HorsesOctober 11, 2016
I’ve held a slight fascination with lobsters for years—probably because my younger self empathized with the American lobsters (Homarus americanus) in the grocery store tanks, with their bound claws (which is basically the same thing as being a kid and never being allowed to do fun things, amirite?). I remember watching them wave their antennae about and clamber over each other in search of the darkest part of the tank, and I’d pick out a favorite each time (always the one with the bluest pigmentation) and secretly wish that I lived near enough to an ocean that I could convince my parents to buy it, so we could release it.
Of course, this never happened. But when we went to visit cousins in Maine my fourth grade self, and a cousin who is about the same age, set to work trying to build ourselves a lobster pot (spoiler: we failed miserably, and broke a pair of scissors in the process, which our parents were none too pleased about). We wanted to catch a lobster that we could release into the natural swimming hole on my cousins’ property.
We wanted to see one up close that wasn’t on its way to being eaten.
Because, of course, that is the fate of so many lobsters. Even as kids, we knew that.
In August 2004, Gourmet Magazine published David Foster Wallace’s essay “Consider the Lobster.” The essay ostensibly focused on the Maine Lobster Festival (then in its 56th year), where 25,000 pounds of lobster are consumed, but interspersed within this are Wallace’s thoughts on eating a sentient creature. Toward the end of the essay, he wrote “Experiments have shown that [lobsters] can detect changes of only a degree or two in water temperature; one reason for their complex migratory cycles (which can often cover 100-plus miles a year) is to pursue the temperatures they like best.”
Now, a recent study demonstrates that lobsters might not just prefer colder temperatures, but that these temperatures may be necessary to their survival. Researchers raised 3,000 baby lobsters from the time they hatched with some being reared in water that was 5 degrees warmer than the others. At this warmer temperature, baby lobster survival rates significantly decreased (although these lobsters grew faster, which can help them avoid predation).
Lobsters lay eggs, and the female lobster carries her eggs in her swimmerettes under her tail until they hatch. After a lobster’s eggs hatch, lobster larvae floats through the ocean (where they might feast on man-o-wars!) and go through several molting stages that occur within the first month. If these postalarva lobsters are lucky, they find a place to settle and become baby lobsters that can grow into adults. Often, due to ocean currents, baby lobsters are found congregated in a particular place, a “lobster nursery,” which is typically composed of cobble, or small stones, that provide shelter for these young lobsters. Babies typically remain in their nurseries for one to two years feeding on plankton and detritus that filter through the water before they venture out to forage. Typically, it takes a lobster 25 molts (over 5 to 7 years in cold water) to grow to the legal minimum catch weight (1 pound).
Maine has a variety of rules governing the capture of lobsters, many of which were implemented to help curb an overfishing problem. The first of these was passed in 1872 and is designed to protect the breeding stock. Under this rule, if a female lobster is egg-bearing, a v-shaped notch must be carved into her right tail fin before she is released. If she is captured in the future (regardless of if she has eggs on her or not), she has to be released, so she can continue to reproduce.
This works well, as long as other factors aren’t applying pressures to lobster populations. However, if fewer baby lobsters live to maturity due to rising ocean temperatures, then the lobster markets in New England could continue to go under (pun intended). This is already happening in Southern New England, where water temperatures are warmer than they’ve historically been, due to changes in the Gulf Stream.
Why should we care?
Lobsters are frequently omnivorous scavengers, which means they essentially act as vacuums of the ocean floor, by eating things that are already dead (or dying). This helps keep the ocean clean, and it’s a specific part of their niche in the ecosystems they inhabit. They’ve also made it through a lot of evolutionary history; last year scientists discovered the fossil remains of Aegirocassis benmoulai, a giant lobster-like creature (the size of a tall human at six and a half feet long) that is believed to have lived about 480 million years ago (dinosaurs, by comparison, first showed up about 230 million years ago, those newbies).
Perhaps, for many of us, the reason we should care is just because we like to eat lobster. Or at least the idea of eating lobster.
Or perhaps we care because (and this would make an environmental economics professor I had years ago so happy), we care just because the existence of lobsters is something we value (someone somewhere who engaged more in environmental economics than I did, can convincingly monetize that).
I’ll be interested to see what future studies are launched by this new research on lobster survival rates in warmer waters. Because, for now, the reality is this: warmer waters and economic pressures are combining to decrease lobster populations in their historic territories. This population decline not only produces economic impacts for towns and villages dependent on the lobster trade. It also has environmental impacts as well—many of which are not currently well understood for the American lobster (but have been more extensively studied in other lobster species).