Smoltification

In honor of the thanksgiving holiday I was thinking of writing about wild turkeys. I looked into it and frankly couldn't find a single surprising or interesting thing about them. They're fantastic and beautiful birds, don't get me wrong. I love seeing them around, and you can in most parts of New England. But they're big birds that eat mostly plants. And they are dumb. So ecologically and behaviorally they're just not so fascinating. The one area I did not check is phylogeny. So I guess I challenge my readers, if you're still out there, to prove me wrong. What's interesting about turkeys?

So I thought of another food animal that's just plain weird: the Atlantic Salmon. Salmon are weird partly because they are anadromous, that is they spend some of their lives in fresh water and some in the ocean. But the really weird thing about the Atlantic salmon is that it goes through up to seven life stages. They all start out as alevin, little larval fish living in the gravel in streams or rivers where they were born. The yolk sac of the egg still attached, they live in relative safety. Not needing to feed they are able to hide from predators all the time.

As the energy store of their yolk sac deminishes they must seek outside sources of nutrients and they change into fry, a common word for larval or young fishes. Fry develop quickly into parr and develop the camouflaging vertical stripes necessary for survival in the gravely rivers where they will spend the next few years of their lives. After several years of dwelling in fresh water they undergo yet another change: their bodies become silver and internal chemistry changes to deal with life in salt water. This process is my new favorite vocabulary word: smoltification, as this next life stage is known as the smolt.

They will then spend two to three years in the ocean as smolts. Those who survive will metamorphose yet again into adults, the males growing a distinctive hook on their lower jaw known as a kype. This hook is involved in mate choice just as many bird species have crests or brightly colored feathers. The full grown adults will return to the riverbeds and spawn. Most of their lives end here, but once in a while an adult salmon returns to the ocean again where it is called a black salmon or a kelt. Usually they will live another two to three years, spawn again and then end their lives in the riverbeds where they were born.

And you thought transforming once from a caterpillar to a butterfly was impressive. Well it is. But check out these crazy fish!

Sources:

Massachusetts Division of Fisheries and Wildlife: http://www.mass.gov/dfwele/dfw/fisheries/anadromous/salmon_life_cycle.htm

Fisheries and Oceans, Canada: http://www2.mar.dfo-mpo.gc.ca/science/mactaquac/lcycle.html

Fishingnet.com: http://www.fishingnet.com/salmon_recognition.htm

What's In a Name?

Most of us know about the caterpillar and the butterfly. These are not two different animals but rather the larval and "adult" stage of the same arthropod. Most, if not all, arthropods have a larval form and the time that is spent in that form can vary drastically. The reason I put "adult" in quotes is because I think in many situations the term is misleading. We assign a level of importance to the final stage of life the animal takes, generally looking at things anthropocentrically with the notion that the more "advanced," "older" form of the organism is its true self. We humans, as adults, tend to think of this period of our lives as who we really are, not the child we grew up from. But in the insect world things don't really work the same way. Here's a couple of examples.

Many species of fly become "adults" only for a single day and lack feeding parts altogether. They are maggots for essentially their entire lives, sometimes years, and metamorphose into their final stage only to fly around, look for a mate, hopefully find one and then die after running out of energy. It seems like these organisms are surely more maggot than fly and yet we insist on calling them flies. They don't really fly all that much, only for a day out of their whole existence.

A similar situation are the "cyclical" cicadas. Many species of cicada live underground as nymphs for thirteen to seventeen years before emerging as "adults." The "adult" phase only lasts about a month, and the main purpose is basically the same: grow wings so you can find a mate more easily. I'm not sure what the ancestral form of the insect world may have been like but it seems that wings may have been an adaptation specifically for finding mates and nothing else. Many of these animals seem perfectly content to spend the vast majority of their lives burrowed underground or in a rotting carcass or up a deer's nose.

So are flies maggots or are maggots flies? Are beetles grubs or is it the other way around? Is it a monarch caterpillar? It's odd to imagine but I wonder how we would look at things if vertebrates spent the bulk of our time on earth in one form and then in our twilight years, just before our cell replication was ready to give out we changed shape into something completely different and flitted off to find a partner with which to reproduce.

References:

Michigan DNRE: http://www.michigan.gov/dnr/0,1607,7-153-10370_12150_12220-26640--,00.html

UC Claremont: http://www.biology.clc.uc.edu/steincarter/cicadas.htm

Turtle "Hibernation"

"The tortoise, like other reptiles, has an arbitrary stomach as well as lungs; and can refrain from eating as well as breathing for a great part of the year." --Gilbert White

I've just been learning about turtle "hibernation," or bromation. Lots of animals apart from those true hibernators can employ periods of deep sleep or vastly reduced metabolic activity. Freshwater turtles that live in parts of the world that freeze over have to go into such a state to survive the cold winter.

What they will do is usually drop to the bottom of a pond or lake. Unless frost line dips below the bottom of the pond the water will remain at 39 degrees F all winter no matter the temperature above because this is the temperature at which water is at its densest. So if it ever cools to below 39 degrees it will begin to float up and away from the turtle.

This might seem extremely cold but the turtle actually does just fine with it. The animal will also, as is the case with most forms of hibernation, lower its metabolism to an extremely low level. Many species' heart rates will fall to one beat about every ten minutes.

What I started wondering is: how do they breathe? Well they have specialized organs in their pharynx and near their anus that have a thin enough membrane that oxygen can be absorbed directly from the water. However, they are still unable to exhale. This means that lactic acid begins to build up in their muscle tissue. To compensate for that (and I think this is the most amazing part) calcium compounds from the shell will dissolve and enter their bloodstream, neutralizing the acid.

It's just wild to think, from a mammal's perspective, that all winter can be spent at the bottom of a lake, completely submerged in near freezing water. Evolution never ceases to amaze me.

Education and Service

So here's some great thinking to wake up to on a semi-frozen November morning...one after an election no less.

I've been having a lot of thoughts involving alarmism and nightmare scenarios. While this is in no way new (I tend to be predisposed to this kind of stuff) I'm just finding myself more and more frustrated with the status quo. What set this off is this: I went to a talk the other day by a science writer who described the Deepwater Horizon accident as the "worst spill in human history."

This is a complicated statement. It's also probably false. We don't have enough data but it's probably true that 3 or 4 oil disasters were technically "bigger" in that they spilled more oil. And all her agitated, furious emoting led me to think about one thing and one thing only. That the speaker would, after lamenting the human-induced environmental degradation of the Louisiana marshland get in a car powered by fossil fuels and drive home.

We're all very angry and most of us don't seem to change our actions.

I know this is not supposed to be a blog about sustainability but to me this isn't necessarily a question of how much oil is left in the Gulf. It's the fact that even when we first started drilling oil it was incredibly damaging to local ecosystems. By its very nature oil is bad for the environment. This has nothing to do with how much is left. The stuff is almost the archetype of pollutant.

So I'm not sure I follow my own thinking but here's where it's gone, in two directions. Is educating enough? Is appreciation enough? I've felt comfortable with my role in all of this. I teach, I get kids and grown ups excited about the natural world. That will mean they'll be better stewards. Right...? Or should I be rethinking this? Should I be on the ground giving service instead?

Secondly: If we're all so angry why don't we do something big. No Impact man has tried this but I think his ambitions are a little too lofty. What if we talk about a strict two or three day boycott of fossil fuels? I'm sure folks who care enough can take a few days off work to boycott dirty energy. I'm sure we could do it over the weekend. My thinking is that until we show the oil industry and the government that we really mean business things are going to stagnate here, where we all care but nothing is really happening. And I'm pretty sure a massive boycott of oil would hit industry in its wallet. I know it's not something we'd be able to keep up: after all we're all dependent on petroleum products. But what if we really committed ourselves to letting go of at least a little bit of that dependency? What then?

Not sure how that's all going to read. As always, I would love to hear your thoughts, whoever you are.