Sponges... they're not just your loofah

Today I will be talking about the Barrel Sponge! To begin, sponges (Phylum Porifera) are one of the most simplistic animals and yes, they are animals. They are sessile meaning they grow and remain in the same spot for their whole life, never moving. Some have been documented to live to be thousands of years old!! Their anatomy and processes are quiet simple. On the exterior part of their body column they are covered in small openings called “pores” that allow water to flow into their bodies. As the water flows through it gets filtered by “choanocytes” which are flagellated cells that line the central cavity. They help move the water being brought in and also capture food, as sponges are filter feeders. They have a large single opening called an “osculum” that allows water and waste to flow out of. The larger the sponge the larger the outflow and some divers have been able to visibly see and film the water flowing out!! They do not have tissue, but rather layers of multipurpose cells along with spicules and spongin fibers that help provide structure and protection to the sponge.

There is a fishing practice known as “bottom trawling” where a large weighted net is dragged along the sea floor with the hopes of collecting animals that live on or near the seafloor like cod, rockfish, flounder, shrimp, or squid for example. BUT this fishing practice is extremely un-selective and destructive. Any area in the wake of a trawl is left completely scrapped and barren of life. Not to mention the bycatch can amount to up to 90% of their load at times. This includes things like sponges, corals, large and small fish and mammal species. This unwanted catch is discarded and are usually dying or dead by the time they are brought up or as an effect of the stress. Since sponges are sessile and do not have the ability to evade this imminent threat, they have no other choice but to be scooped up or smothered.

Originally posted on 18 November 2018

(my pictures from the Florida Keys)