WEST AFRICAN LUNGFISH (Protopterus annectens)
Lungfish are one of those fish we learn about when we are kids, and we go on and on about how cool it is that there is a fish with lungs. Then, you know, you go on and take a whole lot of biology classes and find out that actually a lot of fish have lungs and that lungfish are only really special because their name has the word "lung" in it. Today, I'm going to take them down a notch.
Appearance
West African lungfish belong to a group of bony fishes (as opposed to the sharks which have cartilage instead of bones) called the "lobe finned fishes". The lobe finned fishes include other lungfish, coelacanths, and (technically) all terrestrial vertebrates. The whole point of a lobe fin is that it is sturdier than a regular fish fin, and that sturdy fin was what enabled vertebrate animals to eventually make their move to land. To put this into context, imagine a goldfish trying to walk around on land with its paper thin flimsy-ass fins. It's not gonna work, right?
So, despite lungfish being part of the lobe-finned fish, lungfish have these stupid, thin, floppy fins that kind of look like tendrils which are no use whatsoever. They look like dorky little ribbons and they are in no way capable of supporting the weight of the fish to walk around and stuff. Realistically, they're probably not even that good at swimming by the looks of them.
Points: 0/1
Behaviour
Despite having those weird, thin, floppy fins that are not useful for walking around on land, West African lungfish are obligate air breathers. That means that breathing air is not a casual option for them, but a necessity. They get most of their oxygen from the air and will drown in water. So they need air to live but they are woefully unprepared for living on land.
Granted, they have to do this because the water that they live in dries up for part of the year and they have to live in the mud with little breathing tubes that they use to get air and stuff, but still. It doesn't make a lot of sense that they have shitty fins and I'm mad about it.
Points: 0/1
Distribution
Another weird thing about this particular species of fish that isn't related to their stupid fins: Protopterus annectens is sometimes called the African lungfish, despite being one of four African species of lungfish. So that's misleading. The West African lungfish is sporadically distributed south of the Sahara, and in the eastern part of Africa, so the name West African lungfish is also misleading.
Points: 0/1
Ecology
The West African lungfish breathes air and hangs out in the mud with a little air breathing tube, but it eats primarily aquatic prey like molluscs and sometimes other smaller fish. If they were smart, they would turn their mud burrows into a trap for bugs and then they could have some snacks while they were estivating. Instead, West African lungfish don't eat at all during the estivation period, instead waiting for the water to come back and bring with it other little aquatic animals for them to eat. If you think about it, this is a pretty ballsy strategy. The reason African lungfish are successful at all is because they live in a habitat that other fishes can't, but then they also rely on other fish to be there for part of the year so they can eat them.
Points: 0.5/1 because even though this strategy is pretty stupid, I admire their moxy
Evolution
The main reason that humans find lungfish interesting is that they are the fish most closely related to us. Tetrapods are descended from a group of what could reasonably be called a lungfish (although they are not really the same thing as a modern lungfish), and all of the fish groups that are more closely related to humans than modern lungfish are extinct now. When we try to think about the first fish that walked on land, from which people are ultimately descended, lungfish are probably the closest thing we can get to how they looked and behaved.
But here's the thing: the group called the dipnoi (which is all of the modern lungfish) branched off from the group that would eventually give rise to the tetrapods like, 420 million years or so ago. Since then, lungfish have been doing their own thing and evolving and adapting to their environment for a really, really long time, and so have tetrapods. Do African lungfish retain some of the characteristics that might have been present in the common ancestor of lungfish and people? Probably. Are most of their characteristics specific to lungfish, with no bearing on what said common ancestor was like? Also probably.
Looking to modern lungfish to understand the secrets of how vertebrate life evolved on land is the best option we really have, but it's also vaguely useless. I guess what I'm saying is, we should appreciate lungfish for what they are, rather than what they used to be, or what they say about what we are.
Points: 1/1 I guess? I don't really know what the point of all that was but I feel bad for ragging on lungfish so much and I'm giving them a pity point.
Life History
West African lungfish have tadpole-like larvae which have gills and get 90% of their oxygen from the water. As they develop, they grow more dependent on their one lung and eventually, at maturity, get around 80% of their oxygen from the air. This is, again, weird as fuck because, like I've said before, the place that they live doesn't always have water in it, so there's a possibility that they might dry up before they have a chance to mature, right?
They produce a lot of eggs though so they don't really give that much of a shit if their offspring get dried up because their lungs didn't develop fast enough, they can always just make some more.
Points: 0.5/1 for being ballers but also being really casual about their babies
Interaction with Humans
Lungfish haven't really been harvested for food on a very large scale, which is surprising because they are big and meaty, and they live in the mud where they are sitting ducks. They're not extremely plentiful though. There is some interest in lungfish aquaculture because they're hard to kill and relatively cheap to raise, but you still have to feed them which is inconvenient.
Points: 1/1
Final Score: 3/7
The West African lungfish is okay but not great
Further Reading
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| Image adapted from wikipedia |
Appearance
West African lungfish belong to a group of bony fishes (as opposed to the sharks which have cartilage instead of bones) called the "lobe finned fishes". The lobe finned fishes include other lungfish, coelacanths, and (technically) all terrestrial vertebrates. The whole point of a lobe fin is that it is sturdier than a regular fish fin, and that sturdy fin was what enabled vertebrate animals to eventually make their move to land. To put this into context, imagine a goldfish trying to walk around on land with its paper thin flimsy-ass fins. It's not gonna work, right?
So, despite lungfish being part of the lobe-finned fish, lungfish have these stupid, thin, floppy fins that kind of look like tendrils which are no use whatsoever. They look like dorky little ribbons and they are in no way capable of supporting the weight of the fish to walk around and stuff. Realistically, they're probably not even that good at swimming by the looks of them.
Points: 0/1
Behaviour
Despite having those weird, thin, floppy fins that are not useful for walking around on land, West African lungfish are obligate air breathers. That means that breathing air is not a casual option for them, but a necessity. They get most of their oxygen from the air and will drown in water. So they need air to live but they are woefully unprepared for living on land.
Granted, they have to do this because the water that they live in dries up for part of the year and they have to live in the mud with little breathing tubes that they use to get air and stuff, but still. It doesn't make a lot of sense that they have shitty fins and I'm mad about it.
Points: 0/1
Distribution
Another weird thing about this particular species of fish that isn't related to their stupid fins: Protopterus annectens is sometimes called the African lungfish, despite being one of four African species of lungfish. So that's misleading. The West African lungfish is sporadically distributed south of the Sahara, and in the eastern part of Africa, so the name West African lungfish is also misleading.
Points: 0/1
Ecology
The West African lungfish breathes air and hangs out in the mud with a little air breathing tube, but it eats primarily aquatic prey like molluscs and sometimes other smaller fish. If they were smart, they would turn their mud burrows into a trap for bugs and then they could have some snacks while they were estivating. Instead, West African lungfish don't eat at all during the estivation period, instead waiting for the water to come back and bring with it other little aquatic animals for them to eat. If you think about it, this is a pretty ballsy strategy. The reason African lungfish are successful at all is because they live in a habitat that other fishes can't, but then they also rely on other fish to be there for part of the year so they can eat them.
Points: 0.5/1 because even though this strategy is pretty stupid, I admire their moxy
Evolution
The main reason that humans find lungfish interesting is that they are the fish most closely related to us. Tetrapods are descended from a group of what could reasonably be called a lungfish (although they are not really the same thing as a modern lungfish), and all of the fish groups that are more closely related to humans than modern lungfish are extinct now. When we try to think about the first fish that walked on land, from which people are ultimately descended, lungfish are probably the closest thing we can get to how they looked and behaved.
But here's the thing: the group called the dipnoi (which is all of the modern lungfish) branched off from the group that would eventually give rise to the tetrapods like, 420 million years or so ago. Since then, lungfish have been doing their own thing and evolving and adapting to their environment for a really, really long time, and so have tetrapods. Do African lungfish retain some of the characteristics that might have been present in the common ancestor of lungfish and people? Probably. Are most of their characteristics specific to lungfish, with no bearing on what said common ancestor was like? Also probably.
Looking to modern lungfish to understand the secrets of how vertebrate life evolved on land is the best option we really have, but it's also vaguely useless. I guess what I'm saying is, we should appreciate lungfish for what they are, rather than what they used to be, or what they say about what we are.
Points: 1/1 I guess? I don't really know what the point of all that was but I feel bad for ragging on lungfish so much and I'm giving them a pity point.
Life History
West African lungfish have tadpole-like larvae which have gills and get 90% of their oxygen from the water. As they develop, they grow more dependent on their one lung and eventually, at maturity, get around 80% of their oxygen from the air. This is, again, weird as fuck because, like I've said before, the place that they live doesn't always have water in it, so there's a possibility that they might dry up before they have a chance to mature, right?
They produce a lot of eggs though so they don't really give that much of a shit if their offspring get dried up because their lungs didn't develop fast enough, they can always just make some more.
Points: 0.5/1 for being ballers but also being really casual about their babies
Interaction with Humans
Lungfish haven't really been harvested for food on a very large scale, which is surprising because they are big and meaty, and they live in the mud where they are sitting ducks. They're not extremely plentiful though. There is some interest in lungfish aquaculture because they're hard to kill and relatively cheap to raise, but you still have to feed them which is inconvenient.
Points: 1/1
Final Score: 3/7
The West African lungfish is okay but not great
Further Reading
- Babiker MM. 1979. Respiratory behaviour, oxygen consumption, and relative ependence on aerial respiration in the African lungfish (Protopterus annectens, owen) and an air-breathing teleost (Clarias lazera, C.). Hydrobiologia. 65(2): 177-187.
- Delaney RG, Lahiri S, Fishman AP. 1974. Aestivation of the African lungfish Protopterus aethiopicus: cardiovascular and respiratory functions. Journal of Experimental Biology. 61: 111-128
- Goudswaard KPC, Witte F, Chapman LJ. 2002. Decline of the African lungfish (Protopterus aethiopicus) in Lake Victoria (East Africa). African Journal of Ecology. 40: 42-52.
- IUCN Redlist
- Mlewa CM, Green JM. 2004. Biology of the marbled lungfish, Protopterus aethiopicus Heckel, in Lake Baringo, Kenya. African Journal of Ecology. 42: 338-345.
- Mosille OIIW, Mmnoya JR. 1988. Reproductive biology of the East African lungfish (Protopterus aethiopicus) in Mwana Gulf, Lake Victoria. African Journal of Ecology. 26(2): 149-162.
- Walakira J, Atukunda G, Molnar JJ. 2011. Prospects and potential of the African lungfish (Protopterus spp): an alternative source of fishing and fish farming livelihoods in Uganda and Kenya.
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