Poritidae Family of Pore Corals
One Pore Coral of the Poritidae Family can be found in this website:
Hump Coral, Porites panamensis. A representative of the Poritidae Family of Pore Corals.
Phylogeny: Pore Corals of the Poritidae Family, like Sea Anemones, Jellyfish, and Hydroids, belong to the phylum Cnidaria. They are in the class Hexacorallia, the order Scleractinia, and the suborder Refertina. This suborder contains ten families, including Poritidae. The Poritidae Family is comprised of four genera and around one hundred four species. The name Poritidae comes from the combination an ancient Greek word and a New Latin suffix that means something like “porous-rock” or “porous fossil”. This refers to the porous micro-structure of the corals. Species in this family are also commonly called Lobe Corals, Finger Corals, and Portiids.
Morphology: Pore Corals are Small Polyp Stony corals (SPS). The polyps have radial symmetry, a hollow digestive cavity, and specialized stinging structures contained within the tentacles surrounding the mouth. Their polyps have a flower-like appearance, representative of the class Anthozoa. In addition, their polyps produce a hard, calcareous skeleton, representative of the order Scleractina. They are hermatypic (reef-building) and live in tightly packed colonies where new generations may build upon the skeletons of previous generations, forming coral reefs. Pore Corals fall under the category of hard, or stony corals, as compared to the soft corals, or octocorals. Pore Corals are characterized as having small polyps and porous corallite (cups holding polyps) walls and septa. They are lighter in weight than most corals because of this porosity. Corals in the Poritidae Family may be dome-like, columnar, branching, or grow as encrusting sheets. Pore Corals tend to be brown, gray, cream, or green in color, but they may also be blue, purple, yellow, or pink. The Poritidae Family contains species that form the smallest and largest colonies of all hard corals. Species from the Stylaraea Genus only reach 1.0 cm (0.4 inches) to 2.0 cm (0.8 inches) across. A Porites rus colony in the Mariana Islands measures 62 m (200 feet) across.
Habitat and Distribution: Pore Corals grow on hard substrates such as rocks, dead coral, rubble, pilings, and wreckage. They live along exposed coastlines, in protected lagoons, and in relatively deep water. They require access to sunlight, but in exceptionally clear water they can be found as deep as 100 m (328 feet). Most Pore Corals are found in the first 30 m (99 feet) of the water column. These corals are found worldwide in subtropical and tropical seas. Four species from the Poritidae Family are found in Mexican waters of the Atlantic and Pacific Oceans.
Reproduction: Pore Corals may be gonochoric (male or female for life) or simultaneous hermaphrodites (having both male and female reproductive organs). Reproduction may be asexual or sexual. Sexual reproduction may be through broadcast spawning (releasing gametes into the water, where fertilization occurs) or sperm casting (males release sperm into water and females receive the sperm so fertilization occurs internally, and the eggs are brooded). Spawning may occur year round, depending on lunar cycles and water temperatures. The gametes develop into planktonic planular larvae. Once the larvae find suitable habitat they settle to the substrate and metamorphose into polyps. They then reproduce asexually, through budding, to grow new colonies. Mortality rates are high during the larval stage and early settlement. In addition, reproduction can occur asexually through fragmentation.
Ecosystem Roles: Pore Corals have a symbiotic relationship with zooxanthellae, single-cell dinoflagellates. Zooxanthellae live within certain coral polyps, sea anemones, jellyfish, and nudibranchs. They produce energy by means of photosynthesis and the energy is passed along to their hosts, sometimes providing the majority of the host’s total energy needs. In return, the host provides nutrients, carbon dioxide, and a secure, sunlit, platform for the zooxanthellae. During periods of chemical or thermal stress the corals can eject the zooxanthellae to reduce metabolic stress. This causes the coral to appear white. This process is known as coral bleaching. Coral bleaching can be an indicator of an unhealthy environment, or a natural response to a short-term condition such as El Niño. The coral will replace the zooxanthellae after the stress is resolved, or it will acquire a different species of zooxanthellae that is better accommodated to the new environment. In either case, the polyp risks starvation if it is unable to replace the zooxanthellae quickly. Pore Corals supplement the energy provided by zooxanthellae by using their tentacles to capture amphipods and other plankton from the surrounding water. The tentacles then pass the food to the mouth. They are preyed upon by crabs, fish, gastropods, starfish and polychaete worms. Pore Corals are important contributors to reef growth, and thereby, provide habitat for thousands of other species.