Sponges, Phylum Porifera, Part 1

What a difference a few years makes. Look back a few, maybe a decade ago, and you'd find very few people keeping live Sponges. For those attempting this "holy grail", they either couldn't get healthy specimens or didn't know how to keep them alive. Moreover most hobbyists feared their presence and tried to eliminate them altogether.

Nowadays reefers are "kinder and gentler", not to mention much more knowledgeable regarding these early life forms. They are recognized as what they are; wondrous, filter-feeding adjuncts to modern reef keeping, both as ornamentals in their own right, and substantial components of healthy Live Rock.

There are some Sponge species to be avoided (stinging, stinking and easily dying varieties), but by and large encouraging, even propagating Sponge "material" is very much a part of the reef experience. With care in selection and husbandry you can benefit from the Sponges that do well in captive reef environments.

Classification:

Sponges comprise the phylum Porifera, whose name means "bearing openings"; an allusion to their overall porosity and general mode of feeding (filtration), respiring, excreting wastes while whipping water in through openings in their body walls. Sponges are the simplest form of multicellular animals, just up from protozoans and down from cnidarians (stinging-celled like corals and anemones) in most taxonomic schemes. They don't, in fact, have tissues or organs. Their cells are somewhat unspecialized and quite independent, more like a commune or colony than a single animal.

There are about 5,000 identified marine species of sponges. There are a few ambulatory types but almost all are attached permanently to hard or soft substratums. Sponges are found worldwide, mostly in shallow waters; in all colors and shapes and sizes, from a thumbnail to a washtub. Some are cylinders, others vase-like; most are crustose and irregular (shown: a Caribbean sponge scene off of Tobago, Sponge scene in Tobago, Carib.).

The Porifera live up to their names by having a characteristic arrangement of specialized cells imbedded in a spongy matrix (spongin), incurrent pores (ostia) formed by porocytes allow water into an open space (atrium) in their bodies and out one or more larger openings (oscula-ae). Their outer walls are supported by non-living calcareous or siliceous structural elements called spicules. Along with proteins these are the sponge skeletons of bathroom sponges derived from biological sources.

The reasoning against lifting a sponge from the water is eminently clear in studying the drawing of a sponge. Once air is trapped in the atria, it is exceedingly difficult for the flagella-equipped collar cells or choanocytes to void it. The choanocytes are responsible for producing the water currents through the animal which bring in/out oxygen, carbon-dioxide, sex cells and waste, mainly ammonia. Most all sponges are filter feeders that mainly sieve out very fine particles, though tiny "killer" sponges have been making the news recently that capture larger prey like shrimp.

Provisional identification of sponge species can be trying. They're polymorphic much as Hard Corals, with color (browns, black, green, yellow, purple, pink to red), shape (boring, encrusting patches, ropes, balls, barrels, tubes...shown, examples of shape, color) and size of specimens influenced by factors like depth of water, light, current, and nutrient. To the genus and species determinations are only possible by examining the type, relative abundance and location of spicules in "melted down" live samples.

Species of Interest To Reef Aquarists:

Sponges are incidentally imported from all oceans along with Live Rock. You might be surprised to find that poriferans often make up the most biomass of Live Rock. Specimen sponges for the reef trade themselves are collected out of the Caribbean, Southeast Asia, (and mainly for European aquarists) the east African coast.

From the tropical west Atlantic we get a few species of bright orange and yellow Agelus (2)(shown, Agelus clathrodes, the Orange Elephant Ear Sponge, and an Agelus sp. one of the Brown Tube Sponges when it grows up). Of similar worthiness are Orange Ball Sponges, Cinachyra spp.( pictured)(2). There are a myriad of Vase Sponges out of the Caribbean as well. My favorite genus is Callyspongia (2).

Frequently offered are "Fire" and "Red Ball" Sponges that are mainly Tedania ignis (3). These are far less hardy choices, and can be toxic to your other reef life. I am similarly disdainful of Black-Ball Sponges, Ircinia strobilina and Grantessa hastifera (out of the Mediterranean) pictured)(3), which require bright lighting should you try them just the same.

Of about the same hardiness (3's IMO) though beautiful, are the upright forms like Green Finger Sponge, Iotrochota birotulata (below), Erect Rope Sponge, Amphimedon compressa, and Red-Orange Branching Sponges, Ptilochaulis sp. 

If you are keeping live Stony Corals, boring (as in digging, not yawning) species of Sponges of the genera Cliona (pictured, Cliona delatrix, the Red Boring Sponge; and Variable Boring Sponge, Siphonodictyon coralliphagum (3's) are definitely out. However, strangely enough, if you find the Orange Icing Sponge, Mycale laevis (pictured) growing under your plate-type corals, this is not a "bad thing". This Sponge actually protects the Stony Coral from Boring Sponge infiltration.

From the Red Sea on out to the Indian Ocean, the Red Sponge, Latrunculia corticata (pictured) is about the best red Sponge choice going (2).

Clathria (shown) are encrusting forms that come out of the Caribbean and Far East, and do very well in captivity (1's). They're available in warm colors to white. And do look for other "freebie" sponge specimens on Live Rock (Diplasatrella, Monanchora, Phorbas, Spirastrella and more, (2's) these are encrusting species of red, orange, yellow and brown color.

Agelas clathrodes, the aptly named Elephant Ear Sponge, right size (to a meter and a half across), wrong colour... This pachyderm dimension specimen in Bonaire 8/09
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Agelas conifera, the Brown Tube Sponge. Typically smooth walled, brown to tan in color, smooth, velvety in appearance. Grow in clusters, joined at base. Bonaire pic.

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Bigger PIX: The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

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Bigger PIX: The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

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A Cliona sp. waning

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