EcoSystems

[Paolo Piccinell]

Contact me when you are in Indo

I planned a visit there... unfortunately it's non easy with two small children, but I'll try hard!!! ;-)

 

[ivans75]

haha dont worry about the kids they can hang out with mine, i got 8 and 4 years old too.

 

[elegance coral]

It is my understanding that water clarity varies widely on healthy reefs due to weather, plankton blooms, seasons, tides, storms, etc. and it is very often not "crystal clear," but full of floating particles.

We covered this earlier in the thread.

Lots of plankton can't be maintained without lots of dissolved nutrients to sustain them. There can be temporary plankton blooms without high levels of dissolved nutrients, like mass coral spawning events, but these are temporary. In order to maintain lots of plankton, there has to be lots of dissolved nutrients. We can't say that reefs have little in the way of dissolved nutrients, but lots of plankton. This would be like saying there are lots of lions in Africa, but very few wildebeests. It just doesn't work that way.

The healthier the reef, the better general water clarity is surely true,

I couldn't agree more, and that's all I'm trying to say.

but that doesn't mean it can be described as generally crystal clear. The statements you made above are really just incorrect I think.

Virtually everyone in this thread, myself included, have been using adjectives to describe the clarity of healthy coral reef waters. These terms are open to interpretation, or relative to ones perspective. A poor quality diamond still appears crystal clear when compared to limestone, but may be very cloudy when compared to a high quality diamond. So, if we're trying to quantify the clarity of the waters around healthy tropical coral reefs, what should we compare it to??????? To me, the logical comparison would be other environments that supports a similar abundance of life. If we make this comparison, the waters around healthy coral reefs become crystal clear. These are still naturally occurring waters so they will not be as clear, or nutrient poor, as artificially treated water. Such as the water that comes from our RO/DI filters.

The waters around healthy tropical coral reefs would support very little life due to its low nutrient content and clarity, if it weren't for the symbiotic relationship between corals and their zooxanthellae. These waters are simply to clean, and therefor clear, to support the vast majority of life forms on this planet. If this unique relationship did not exists, the areas that now support healthy coral reefs would be largely baron of life. You would only find the few specialist organisms that somehow manage to find enough to survive on, like oceanic white tip sharks that can go long periods of time between meals.

There are people like the suppliers of "Miracle Mud", other similar products, and Ron Shemik that have convinced some hobbyists that healthy coral reefs prosper is swamps. They don't! Healthy coral reefs prosper in very clean and clear environments. Not swamp like environments that are loaded with nutrients.

 

[Gravesj1s]

It's been shown in several corals that were studied, actually digest the zooxanthellae themselves. This means they obtain more than just carbohydrates from their zooxanthellae. They also obtain nutrients like phosphate, nitrogen, and amino acids from the zooxanthellae cell walls.

Elegancecoral,

Im curious about the above statement.Do you have a source I can look at ,because thats not quite what Ive read.My understanding is that zooxanthellae are not actually consumed but rather the carbon they produce is,and they are regulated and expelled not consumed.
Thanks.

-Steve

 

[Flanders]

The waters around healthy tropical coral reefs would support very little life due to its low nutrient content and clarity, if it weren't for the symbiotic relationship between corals and their zooxanthellae. These waters are simply to clean, and therefor clear, to support the vast majority of life forms on this planet. If this unique relationship did not exists, the areas that now support healthy coral reefs would be largely baron of life. You would only find the few specialist organisms that somehow manage to find enough to survive on, like oceanic white tip sharks that can go long periods of time between meals.

But healthy stony coral reefs also support huge populations of fish and filter feeders because there is an abundance of various types of phyto and zooplankton, marine snow and God knows what else for them to feed on. Have you ever seen photos of dendronepthyas lining the underside of huge table acroporas? They are feeding on something.

Maybe part of the problem is we are talking in generalities about a type of ecosystem that varies widely. I don't mean to seem argumentative but healthy coral reefs are (generally) not acropora deserts devoid of fish because there is no food. Dissolved nutrients may be low, but food is drifting in from somewhere, a lot of it, so much that it is so far nearly impossible to keep some of the organisms that live there in captivity.

 

[thebanker]

... have convinced some hobbyists that healthy coral reefs prosper is swamps. They don't! Healthy coral reefs prosper in very clean and clear environments. Not swamp like environments that are loaded with nutrients.

I think we're at the point where we need to start citing scientific journals.


I haven't been to every reef on the planet but I have been to:

- The bahamas
- South florida coast
- The french west indies (st. martin, st. barthelemy, etc)
- The yucatan (cozumel)
- The west coast of Mexico (bahias de huatulco)
- Hawaii (kauai, big island, maui)

and I can say that on each and every excursion to living stony reefs, the water was full of particulate matter. Not so much that you can't see, but enough to create that backscatter of tiny particles, everywhere you look. Is the water clear? Sure. Most of the time, but the particles are always there, even on clearest of days. And some days aren't so clear, and the water looks dirty.

Even where I live, in southern CA, there are planktonic blooms that are so thick, at night you can touch the ocean and send phosphorescent green ripples from your fingertips. I wouldn't consider our local ecology a "reef" in the terms we're talking about here, but the water is very clear, and very full of biological particulate matter.

 

[elegance coral]

Elegancecoral,

Im curious about the above statement.Do you have a source I can look at ,because thats not quite what Ive read.My understanding is that zooxanthellae are not actually consumed but rather the carbon they produce is,and they are regulated and expelled not consumed.
Thanks.

-Steve

Here's one. http://www.google.com/url?sa=t&rct=...55HTDA&usg=AFQjCNFVyJmWET6MBnHSZgwOlxvWPh9jgQ

A quote from the link. "It is concluded that hermatypic corals are capable of regulating their zooxanthellae populatia by digestion and extruion of zooxanthellae remnants ."

Here's another. http://books.google.com/books?id=4h...X&ei=BqdaT7nML4WKsALgirjUDQ&ved=0CC8Q6AEwAjgK

here's one on T. clams. http://www.biolbull.org/content/141/2/222.short

here's one on an anemone that "farms" its zooxanthellae
http://onlinelibrary.wiley.com/doi/10.1111/j.1469-7998.1977.tb03255.x/abstract

Here's one on planulae
http://www.springerlink.com/index/VVTE5TH2LNFX32KV.pdf

If you do some googling, you can find a great deal more reading on the subject.
HTH
EC

 

[elegance coral]

I'm not really sure who is trying to prove what in this thread any more, considering it's gone way off topic, but I've never been on a reef (even a "healthy growing tropical reef") that had anything close to truly "crystal clear" water. Even on days when visibility was very high (in terms of feet), there was always a TON of stuff in the water - particulate matter, plankton, whatever it was, it was definitely there, in much higher concentrations than I've ever seen in a home aquarium.

I'm posting here not because I desire to be dragged into an argument, but rather because this lack of particulate matter/plankton/whatever in the water column of an average reef tank is something that I've been wondering about for years. Clearly, to me at least, natural reefs often thrive when levels of this "stuff" in the water column are higher than in home aquariums (though, of course, there's also clearly an upper limit - if the water around a reef was too clouded with an extremely high level of debris, you'd expect decline.)

I don't want to argue either. You've got to understand how confusing, and misleading your statements are though. In your first paragraph you state that, "Even on days when visibility was very high (in terms of feet), there was always a TON of stuff in the water..." This defies the laws of physics. We can't see through solid matter. If you put a "TON" of stuff in the water, the visibility goes down. Visibility goes up (in terms of feet) when there is not a "TON" of stuff in the water. Then in the very next paragraph you say, "if the water around a reef was too clouded with an extremely high level of debris, you'd expect decline." Which I agree with. Isn't "a TON of stuff" and "an extremely high level of debris" the same thing????

But does that imply a causal relationship? If so, in which direction? Do the reefs thrive in these areas because they are "nutrient poor" or are the areas nutrient poor because the reef has thrived there?

The reefs thrive there because the water is nutrient poor. The water would still be nutrient poor if you could magically remove all the coral reefs. It is the phytoplankton in the northern Pacific that makes these waters nutrient poor. In the link below you'll see that cold, dense, and deep, waters move north in the Pacific along the great abyssal plane (the worlds largest DSB). It picks up nitrogen, phosphorus, and other nutrients from this DSB as it moves north. When it reaches the north, these high nutrient waters are pushed to the surface, where they are exposed to light, and it creates massive algae blooms. (Which is the same thing DSB's do in our little glass boxes.) These waters are then pushed south along the surface as it's being stripped of nutrients by these algae blooms/phytoplankton. By the time these waters reach the tropics and the countless coral reefs, they are very nutrient poor.

http://www.google.com/imgres?q=ocea...rt=0&ndsp=17&ved=1t:429,r:10,s:0&tx=116&ty=51

At any rate, when you say "nutrient poor" are you talking about dissolved, inorganic nutrients, or total nutrients? i.e. NO3 or total nitrogen?

I'm talking about nutrients like nitrogen, phosphorus, and others that are needed to support life.

Are we implying a correlation between nutrient levels (which levels of which nutrients) and amount of visible "stuff" suspended in the water column?

Absolutely. If you could say there is a beginning to the food chain, most people would consider dissolved nutrients to be that beginning. Without dissolved nutrients, there is no phytoplankton. Without phytoplankton, there's no zooplankton. As I've said earlier in this thread, you can't maintain high levels of stuff (phyto/zooplankton) without the dissolved nutrients to support it. In the northern Pacific there is a high level of nutrients, and a high level of "stuff" in the water. In the tropics, around healthy coral reefs, there is a low level of nutrients, and low levels of "stuff" in the water.

It is not high levels of "stuff" in the water that makes these ecosystems possible. It is the unique relationship between corals and their zooxanthellae that allow these ecosystems to exist. This relationship allows corals to grow in an environment that otherwise would not contain enough nutrients to sustain them. These corals then kick start a whole food web that supports a huge variety of organisms. Microbes feed on coral slime. Slightly larger organisms feed on these microbes. Still larger organisms feed on them. There are organisms that feed directly on the corals themselves. Then larger organisms feed on them. All of the organisms that prosper around healthy, growing, tropical, coral reefs owe their existence to the special relationship between coral and their zooxanthellae. Not to an abundance of "stuff" in the water. The vast majority of "stuff" that is in the water owes its existence to this relationship. Take away this relationship and the whole system breaks down, because there is not enough nutrients in the water to support it.

 

[r-balljunkie]

EC,

please dont take these question(s) the wrong way.

1) do you have any 'in water experience' on an actual reef, aside from keeping an aquarium?

2) Are you dive certified?

once again, please dont tank this as a personal attack. just opening this forum up to questions.

C

 

[elegance coral]

1) do you have any 'in water experience' on an actual reef, aside from keeping an aquarium?

Yes.

2) Are you dive certified?

No.

In my youth, I was a very skilled swimmer/snorkeler. I can still do okay, but nothing like I did back in the day. I have visited several places in the Caribbean. For several years, I was in the waters of the Florida Keys every other weekend, and on most of my vacations. So, I've spent countless hours on and around coral reefs.

once again, please dont tank this as a personal attack. just opening this forum up to questions.
C

No problem at all. You can ask what ever you like. Your post was very polite. :thumbsup:


We can learn a great deal from swimming on a reef and observing things first hand. However, its hard to understand how the things we see on a reef work, or function, without cracking a book. There's a wealth of information to be had, that we can not obtain simply by swimming on a reef. When someone wants to become a marine biologist, we don't throw them a SCUBA tank and some flippers, and say, "Here, go swim on that reef for four years and well give you a diploma". We hand them a book and say, "Start reading and well talk about the SCUBA tank and flippers later". We can live in a forest all our lives and never understand what makes the trees grow. Just because someone spends time on a reef, it does not indicate that they understand the processes that take place there.

 

[elegance coral]

I have no idea what you are trying to show here elegance, you said something before and contradict yourself while trying to correct your statement. Very confusing perhaps my english is not very good...

Something most have been lost in translation. I stand behind every statement I've made in this thread. At no point have I contradicted myself, and I've made no statements that I feel need correcting.

You were saying coral reef water is crystal clear now you are saying its not and some in the state of decline and some not.

No. From the very beginning of this thread I've been talking about healthy coral reefs, and I've made it a point to emphasize that fact over and over again. There is a huge difference between the conditions around a healthy growing reef, and one that's on the verge of death.

And yet you are saying again finally that the healthy coral reef is in crystal clear water.

Exactly.

There is no such thing as crystal clear.

You are trying to split hairs. If you don't like the term "crystal clear" use something else. Try, the water is so void of particulate matter that you can see great distances under water. Or how about, the water is so clear that photosynthetic corals can live below 60 meters, or roughly 200 feet.
http://www.google.com/url?sa=t&rct=...utGdDw&usg=AFQjCNFg_gclwcojXfRZBOWKZm4J0HdHvg

 

[elegance coral]

Any idea where Elegance corals came from? They are around in turbid water, quite murky on the mud yes on the mud.

I've been studying elegance corals for the past 25 years, so I believe I know where they're from. Due to their life cycle, they are actually the best example (I know of) to demonstrate that stony corals prosper in clean, nutrient poor water. Not turbid, murky, or muddy habitats.

Elegance coral larvae can not settle in sandy grass flats or muddy sediments. The first tide change, or storm that moved through would disturb the bottom, and cover the tiny larvae causing it to die. They need a solid and fixed structure to settle on, go through metamorphosis, and grow. This is typically the reef itself. As the newly settled coral grows, it takes on the appearance of an ice cream cone standing up on its tip. This is a very tiny point of attachment for a coral that's getting larger and larger. At some point, it will break free of the reef. There are many variables that determine where these corals will spend the rest of their lives. The size of the coral when it breaks free, and the speed and direction of the water have a great impact on this. If the coral is relatively small and a large powerful storm moves through, the coral may be washed great distances away and end up in rubble zones, or grass flats. If the coral is growing on the fore reef, it may simply drop to the deep silt beds below. The coral may simply tip over, or fall just a few feet, and spend the rest of its life on the reef itself. This is why we find elegance corals in many different habitats. From clean nutrient poor waters, to turbid muddy environments. Basically anywhere they can hang on and eek out an existence. Even siblings from the same parent coral, may be found in completely different habitats. The growth, and overall health of the coral is influenced by the environment it lives in. This creates corals that may look very different. So different that at one point it was suggested that there were actually two species of "elegance corals". Catalaphyllia jardeni, the larger, faster growing, coral with long tentacles, and Catalaphyllia picteti, the smaller, slower growing, coral with short stubby tentacles. We now know that there is only one species, and the differences are simply environmentally influenced. Due to the wide range of habitats this coral can live in, we can examine individuals from these different habitats and determine what environmental influences enable them to prosper, and what environmental influences cause them to struggle.

If we examine C. jardeni from turbid, nutrient rich environments, like grass flats, rubble zones, or deep silt beds, we typically find skeletons that resemble small flattened cone shapes. These corals typically grow somewhere around 1/4" per year, and have comparatively short tentacles. These are the corals that were once mistakenly refereed to as C. picteti. If we examine corals from more nutrient poor environments, like the reef itself, or near by, we find corals that grow much larger, have meandering skeletons, and long tentacles. These corals typically grow around 1 1/4" per year, or more. Easily four or five times the growth rate of their relatives in more nutrient rich environments.

So, elegance corals are the perfect example to show that stony corals prosper in clean nutrient poor water. Not turbid nutrient rich waters.

 

[atreis]

EC,

please dont take these question(s) the wrong way.

1) do you have any 'in water experience' on an actual reef, aside from keeping an aquarium?

2) Are you dive certified?

once again, please dont tank this as a personal attack. just opening this forum up to questions.

C

While perhaps interesting, it's not relevant. One does not have to have personally been to the moon to know that it can't support life.

 

[elegance coral]

on the 4th pictures from the bottom, the montiporas and sps are thriving. The camera used was only a pocket camera in waterproof bag.

Considering that the pic was taken through a plastic bag, and with a "pocket camera", it looks pretty clear to me. If you look at the montipora in the bottom right, there doesn't seem to be any sedimentation on top of it like you see in your other photos. That photo looks clean and healthy in comparison to the other photos you posted. At least IMHO.

Those photos are taken from many areas surroundin. Yes there are some dead patches photos but thats due to its closer to the land and the island is quite populated.

And why is it that populated land would cause dead spots on nearby reefs???? It's because populated land puts more "stuff" in the water. Both dissolved nutrients, and particulate matter. It is this "stuff" in the water that's killing the reef.

 

[Gravesj1s]

Here's one. http://www.google.com/url?sa=t&rct=...55HTDA&usg=AFQjCNFVyJmWET6MBnHSZgwOlxvWPh9jgQ

A quote from the link. "It is concluded that hermatypic corals are capable of regulating their zooxanthellae populatia by digestion and extruion of zooxanthellae remnants ."

Here's another. http://books.google.com/books?id=4h...X&ei=BqdaT7nML4WKsALgirjUDQ&ved=0CC8Q6AEwAjgK

here's one on T. clams. http://www.biolbull.org/content/141/2/222.short

here's one on an anemone that "farms" its zooxanthellae
http://onlinelibrary.wiley.com/doi/10.1111/j.1469-7998.1977.tb03255.x/abstract

Here's one on planulae
http://www.springerlink.com/index/VVTE5TH2LNFX32KV.pdf

If you do some googling, you can find a great deal more reading on the subject.
HTH
EC

Thanks,EC.Some interesting reads there.The first couple links give the impression of starvation leading to a coral consuming its host as proof ,whitch Id have a hard time accepting that.Another of the links mentions consuming infected zoaxanthellae.The one link on planulae looks to be solid and makes much more sense considering how limiting nutrients are said to be its more logical to think a coral would be consuming some of it and not just expelling excess.Great links,thanks again.

-Steve

 

[Gravesj1s]

Elegance C.

I ,personally have not been diving or snorkeled many reefs at all.But ,Ive watched many ocean reef documentaries,and one of the things in almost every scene is the amount of pom & plankton being blown around,in fact I dont think Ive ever seen a video without it.

Are they really that crystal clear?

-Steve

 

[Flanders]

Okay, here is an abstract of a summary of plankton density on the GBR.

http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=5343964

Analysis of plankton in the southern Great Barrier Reef: abundance and roles in throphodynamics

Yu. I. Sorokina1 p1 c1 and P. Yu. Sorokina1 p1

a1 Department of Chemical Engineering, University of Queensland, St Lucia

4067, Queensland, Australia

Abstract
Wet biomass of principal plankton components and whole plankton standing stock were assessed in waters of the Heron Island ring reef and surrounding deep lagoon. Biomass of phytoplankton ranged between 30 to 120 mg m−3, without its pronounced depletion over the reef shallows. Picocyanobacteria and prochlorophyte algae contributed over 70% of this biomass. Biomass of bacterioplankton varied between 75 to 340 mg m−3, with its maximum over the reef flat. Biomass of planktonic protozoa's ciliates and zooflagellates ranged between 20 to 110 mg m−3. The daytime biomass of zooplankton varied between 490 to 1590 mg m−3 in the deep lagoon in the zone of intense tidal currents. Over the reef shallows, it was 10"“20 mg m−3. At night, it rose there up to 800 to 4000 mg m−3 as the result of emerging demersal zooplankton from the benthic substrates. The time scale of nocturnal emerging by different taxa was also documented. Biomass of whole demersal zooplankton communities hiding by the daytime in bottom substrates at the reef flat was found to be over 100 g m−2. Problems of nutrition planktivore reef fauna related to the plankton production and abundance are discussed.

So there is clearly no lack of "stuff" in the water - or plankton. Just to clear that up.

Whether reefs are "nutrient poor" depends on what you mean by that term. They are low in dissolved organic nutrients. But that doesn't mean those nutrients aren't there - aren't they within the cells of every plant and animal and tightly recycled as zooplankton prey on phytoplankton, corals and fish prey on zooplankton, etc.? That is my understanding.

 

[elegance coral]

Okay, here is an abstract of a summary of plankton density on the GBR.

http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=5343964



So there is clearly no lack of "stuff" in the water - or plankton. Just to clear that up.

It does "clear that up", but just not in the way you are thinking it does.

Lets put the info from your link into a form that hobbyists are more accustom to dealing with.

Your quote said, " Biomass of phytoplankton ranged between 30 to 120 mg m−3, without its pronounced depletion over the reef shallows."

One m-3 is roughly 264 gallons. 30mg is equal to 0.001058oz, and 120mg is equal to 0.004232oz. So, this is equivalent to having 0.001058 to 0.004232 ounces of phytoplankton in a 264 gallon aquarium. You're never even going to notice such a small amount of phytoplankton in a volume of water that large.

Zooplankton during the day, over the reef shallows, ranged from 10 to 20 mg m-3. That's equivalent to 0.000352 to 0.00705 ounces of zooplankton in a 264 gallon tank. Again, this is nothing. At its peak, at night, the zooplankton concentration rose to 0.141095 ounces in 264 gallons. Still nothing I would consider a "TON", or "lots" of plankton. Even at its peek the concentrations seem pretty minuscule to me.

Here's some photos taken under water around Heron Island Australia where the research your sited was done. The water looks pretty clean and clear to me. http://www.google.com/search?q=dive...a=X&oi=mode_link&ct=mode&cd=2&ved=0CEQQ_AUoAQ

Whether reefs are "nutrient poor" depends on what you mean by that term. They are low in dissolved organic nutrients. But that doesn't mean those nutrients aren't there - aren't they within the cells of every plant and animal and tightly recycled as zooplankton prey on phytoplankton, corals and fish prey on zooplankton, etc.? That is my understanding.

Yes. You are correct. The only dispute here is the abundance of nutrients. Both in the water, and particulate mater/plankton. Fish do prey on plankton. That doesn't mean there is an abundance of plankton for them to feed on around healthy growing coral reefs. Just look at the fish that are exclusively planktivores, like anthias. There isn't enough plankton in the water for them to pig out, then spend the rest of their day protecting territory, relaxing, or making babies. They have to stay in the open water above the reef most of the day, facing the incoming current, and take advantage of each precious little morsel that passes their way. There isn't enough food in the water for them to gorge on all at once. This is one of the reasons people in the hobby have problems keeping these fish. They feed on very little quantities all day long. If there were "a TON", or "LOTS" of plankton, these fish wouldn't need to leave themselves vulnerable in the open water for such long periods of time. They could simply pig out, then return to the safety of the reef.

 

[Flanders]

But what do you imagine is keeping those sun corals alive in this photo you linked to other than large amounts of food delivered regularly? This is what I still don't understand.

And I don't know how the anthias example makes any sense. If they were capable of gorging themselves and relaxing like you're saying, wouldn't they also be a lot easier to keep in our aquariums? It might not have anything to do with the amount of food in the water, it might have to do with the way they have evolved to eat. And other reef fish can gorge themselves, so I don't know how you can really draw any conclusions.

Also I have to give it up to you for doing math on a weekend.

 

[elegance coral]

But what do you imagine is keeping those sun corals alive in this photo you linked to other than large amounts of food delivered regularly? This is what I still don't understand.

You are correct in what you said. There is enough food "delivered regularly" to sustain the coral. That doesn't mean there's "LOTS" of plankton in the water were the coral is right now, or that there's a high concentration of plankton around the reef right now.

These corals can feed any time throughout the day. It looks like quite a few of the polyps are out in the photo. Lets just say the coral is feeding during the 12 hours of darkness and the water is moving at 2 miles an hour. (slower than the average human walks) This would mean there is a column of water stretching out 24 miles long, that will wash over the coral in one night. That's a whole bunch of water. How much food does the coral need in one night? Spread that amount of plankton over a 24 mile long span of water, and the concentration will be incredibly low. If the coral is feeding longer than just 12 hours, or the water is moving faster than 2 miles an hour, the concentration of plankton can be even lower and still have the ability to sustain the coral. These waters can appear very clear and clean, with a very low concentration of plankton, and still support animals like this, because they are exposed to vast amounts of water.

And I don't know how the anthias example makes any sense. If they were capable of gorging themselves and relaxing like you're saying, wouldn't they also be a lot easier to keep in our aquariums?

Absolutely they would. Their relatives, the bass and groupers, do have the ability to gorge themselves, and they are some of the easiest fish to keep in the hobby.

It might not have anything to do with the amount of food in the water, it might have to do with the way they have evolved to eat.

They evolved to feed in a way, and an environment, were there is not an abundance of food available right here, right now. They have become highly specialized creatures. Everything about their anatomy has been fine tuned to the lifestyle they live. They are incredibly powerful swimmers, with huge caudal fins, and a streamline body, capable of incredible bursts of speed. This is needed to escape from predators in the open water where they feed, and to be efficient at capturing the tiny prey they feed on. Their digestive system has evolved to process tiny particles stretched out over a long period of time. There isn't a huge concentration of food in the water, so the fish has to pick off a tidbit of food here, then some time later, another tidbit there. They have to do this over long periods of time to get enough food to sustain them. Over evolutionary time, their digestive systems have become specialized for this type of feeding. They have lost the ability to gorge themselves like their relatives the bass and groupers, because such an ability is not needed for their way of life. If they had this ability, it would be useless because there isn't enough food in the water for them to gorge on. This is the way evolution works. Birds that find themselves on isolated islands with no ground predators often lose the ability of flight, and their wings shrink. Wings, and flight are no longer needed for their way of life, so they are lost.

And other reef fish can gorge themselves, so I don't know how you can really draw any conclusions.

Other fish feed in other ways, and on other foods. Groupers aren't directly dependent on tiny particles that just happen to drift by like anthias are. They can feed on one large meal, then not feed again for days. Anthias don't have that ability because it's not needed for their way of life. Anthias need to feed over a long period of time to get enough to sustain them because there isn't enough plankton in the water, right here, right now, for them to feast on.

Also I have to give it up to you for doing math on a weekend.

Trust me, I was struggling. :lol: