Sponges - the most dominate species in the ocean?

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Sponges

Most primitive metazoan – Multicellular animals

Symbiosis – mutually beneficial relationships with many other organisms

Over 10,000 species

Sedentary/sessile (immobile)

Few mm to over m in size

Grow slow and can get very old

A sponge farmer must have a basic understanding of sponge biology, their life cycle, what they eat, and how they reproduce to grow a healthy and bountiful sponge crop.

Five main cell types

1.     Choanocytes = collar ells with cilia that whip back and forth

2.     Porocytes – Cells with holes (ostia or pores

3.     Sclerocytes = Cells that form spicules

4.     Amoebocytes = cells that can move and differentiate

5.     Spongocytes = cells that form sponging and collagen (Connective tissue)

Spicules are made from either CaCO3 or SO2

Sponges feeding strategy

Filter feeders (plankton, bacteria)

In general, the more food particles in the water surrounding a ponge, the faster it will grow.

Oxygen, nutrients uptake is facilitated by choanocytes and porocytes

Waste excretion (CO2, ammonia)

Amoeboid cells facilitate waste removal and oxygen distribution

Sponge Reproduction

Sexual reproduction: Most sponges are hermaphrodites (Produce both sperms and eggs, self fertizaition)

Gemmulae: Some sponges release small packets of cells that settle to the bottom and create a new sponge

Budding: Some sponges reproduce by forming buds that separate

Regeneration: When a sponge is damaged or cut into small pieces, as may happen in a storm, each piece can grow into a new sponge. (It is this ability to reproduce from small cuttings that makes commercial sponge farming feasible)

Commercial sponge farms

Most of the activity in sponge aquaculture is occurring in the Federated States of Micronesia and other US-Affiliated Pacific countries

In the late 1930s and early 1940’s, Japanese farmers in Micronesia experimented with different sponge growing techniques but their efforts were halted by the outbreak of World War II

Leading expert in sponge aquaculture: Richard Croft, sponge farmer and researcher living in Pohnpei, Federated States of Micronesia

Location of a Sponge farm

The aquaculture species should be native to the area

Keep the sponges away from fresh water

The water should be at least five feet deep at low tide to avoid overheating and UV damage but should be manageable

Cost of sponge aquaculture

Low cost – Material cost <1000$ USD

Three benefits of sponge aquaculture

1.     It’s easy – very little special knowledge required

2.     It’s profitable – Source of continuous income year round….Two sponge farmers working three half days per week can expect to plant 30,000 sponge cutting in a year and earn approx. 10,000 to 12,000$

3.     It’s environmentally friendly – No harm to marine ecosystems if done well…..Reduction of harvesting pressures on local wild sponge stocks……Automatic restocking as a side effect (Site has to be chosen carefully)

Sponge growth rate

-Generally, most species of sponges grow slowly

-Growth is species-depedent

-Sponge growth is temperature-dependent

Artificial selection can be done to enhance growth rates

Q10 effect – with every 10C increase in environment temperature, there is doubling in growth.

Commercial markets and applications

Natural sponges are currently in considerable demand worldwide for their numerous medical, industrial, cosmetic and household uses, including:

1.     Hospital purchase natural sponges because of their unique ability to withstand high sterilization temperatures

2.     Use for bathing and cosmetic purposes

3.     Use for window washing

4.     Use for the application of industrial lubricants

5.     Use as gifts and art products

Sponge broodstock

-Broodstock = supply of parent sponges

-Parent sponge is cut into pieces and each cutting will grow into a new, full sized sponge

Broodstock can be obtained from:

a)    Wild stocks

b)   Donated by government nurseries

c)    Purchased from other sponge farmers

Sponge grow-out methods

Selection of grow-out method is usually based on:

a)    The cost of the materials

b)   The ease with which a farmer can work on the sponges

c)    The adaptability of the technique to different reef conditions

Grow out methods:

1.     Attachment of sponges to concrete discs along the bottom of the ocean

2.     Hanging of sponges on vertical lines extending from bamboo rafts

3.     Hanging of sponges along lines attached to beer bottle floats

4.     Horizontal line method (Currently the most widely used and economical)