The scleratinian (stony) coral Diploria strigosa is the most common of the three Diploria species, all of which are endemic to (i.e., found only in) the Atlantic-Caribbean region. This species form crusts, plates, and sub-massive and massive boulders across a wide depth distribution (0 to 35 meters) and is abundant across most reef habitats in the Caribbean region. It is a simultaneous hermaphrodite (i.e., a single individual functions as both male and female) and a broadcast spawner, releasing large, orange gamete (egg and sperm) bundles during the summer, with a single gametogenic (gamete-producing) cycle per year. In broadcast spawners, such as Diploria strigosa, gametes are released into the water and fertilization takes place in the water column. (In the small minority of coral species [although majority of non-stony coral species] with internal fertilization, known as brooders, sperm are released into the water and swim to another polyp containing the eggs, enter through the mouth, and fertilize the eggs; larvae then develop within the polyps.) (Weil and Vargas 2010 and references therein)

“Colonies form smoothly contoured plates to hemispherical domes, up to 1.8 m in diameter. The surfaces of the colonies have long valleys, which are often connected and usually convoluted, except near the colony's edge. Ridges evenly rounded, usually without a top groove, although occasionally with an extremely fine groove, especially near the colony's edge. The costae between adjacent corallites are continuous, and all costae are equal in thickness. Valleys are highly convoluted and often interconnected (Symmetrical brain coral” (Diploria strigosa).

Color- Green to brown, bluish gray and yellow- brown

occurs (regularly, as a native taxon) in multiple nations

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) Widespread distribution in the tropical western Atlantic, including the Gulf of Mexico, southern Florida, Bahamas, NW Caribbean, Puerto Rico, lesser Antilles and Bermuda. B71SMI01FCUS: Bermuda, Florida, Bahamas, West Indies. B78COL01FCUS: Caribbean, northern Gulf of Mexico. A82CAI01FCUS: Belize. B86STE01FCUS, A82DOD01FCUS, A85FRI01FCUS, A74SCO01FCUS, A78DRY01FCUS: Bermuda. A84BRI01FCUS, A83FAR01FCUS, A88TUN01FCUS: Gulf of Mexico. A81JOR01FCUS, A88FEN00FCUS: Mexico. A74KUH01FCUS, B82ZLA01FCUS: Cuba. A59GOR01FCUS, A67GOR01FCUS, A81LID01FCUS, A87LID00FCUS: Jamaica. A63ALM01FCUS, A76LOY01FCUS, A70PRE01FCUS: Puerto Rico. A74LEW01FCUS, A79DUN01FCUS, A83ROG01FCUS, A84ROG00FCUS, A87TOM01FCUS, A72ROB01FCUS: lesser Antilles. A74SCA01FCUS, A78FOC01FCUS: Bonaire. B84JAA00FCUS, A82DAV00FCUS, A89GLY00FCUS, A85BUR00FCUS, A85WHI01FCUS, J88WHE00FCUS, J89JAA00FCUS: southern Florida. A84LAS02FCUS: Panama.

The genus Diploria is a conspicuous, common, and abundant reef-building group throughout the wider Caribbean. It is endemic to (i.e., found only in) the Atlantic-Caribbean (Weil and Vargas 2010).

D. strigosa is very common on the reefs of the Bahamas, Carribean, and Bermuda (Evans).

Diploria strigosa forms medium-sized, hemispherical, yellow, brown, or greenish colonies. Hills are rounded (not sharp) and almost as wide as valleys--to 4.5 mm--without depressions. 15-20 septa per cm. (Kaplan 1982)

Diploria clivosa is usually encrusting, rarely hemispherical. Hills are sharp and narrow--to 1.5 mm wide (valleys to 6 mm); alternating wide and narrow septa, ~35/cm; not found in Bermuda or Brazil. (Kaplan 1982)

Diploria labyrinthiformis has flat, wide hills--to 2 cm wide, with much narrower valleys. A depression runs the length of each hill. 14-17 septa per cm. Common in rear zone. (Kaplan 1982)

• Marine

Habitat Type: Marine

Comments: Overall depth range from 0-55 m, but typically occurs between 2-15 m on most reef classes.

A67GOR01FCUS: 0 to 40 m, typically 3 to 10 m depth. B86STE01FCUS: 1 to 8 m, inner/outer reefs, muddy bays. A82CAI01FCUS: 0 to 2 m, back reef. A85WHI01FCUS, J88WHE00FCUS: fore reef and spur and groove (5-15 m). B84JAA00FCUS: transitional reefs. A84BRI01FCUS: 15-55 m at Flower Gardens. A88JAA01FCUS: dominant patch reef species. A89DAH00FCUS: fore reef (5 m).

Diploria strigosa forms crusts, plates, and sub-massive and massive boulders along a wide depth distribution (0 to 35 meters), and is abundant across most reef habitats in the Caribbean (Weil and Vargas 2010).

Inhabit many marine environments, down to 40 m (Symmetrical brain coral (Diploria strigosa).

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

SEDENTARY

The encrusting and excavating Caribbean sponge Cliona tenuis competes for space with the coral Diploria strigosa by aggressively undermining and displacing live coral tissue (López-Victoria et al. 2006).

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 to >300

Comments: Information is needed on the number of occurrences in the tropical western Atlantic.

1000 - 2500 individuals

Comments: Limited to reef-class communities such as patch reefs, fringing reefs, spur and groove reefs, transitional reefs and deeper intermediate reefs.

A84PET01FCUS, A89GLY00FCUS, A75GAR01FCUS: black band disease, protozoan parasites. A84LAS02FCUS, A90GHI01FCUS, A91WIL01FCUS: susceptible to bleaching (loss of zooxanthellae) due to adverse environmental conditions. A92COL01FCUS: salinity tolerance to 55 ppt for 12 h. A90TOM01FCUS: growth rate at .32-.45 cm/yr. A84BRI01FCUS: growth rate .5 cm/yr at 21 m. A15VAU01FCUS: growth rate at .59-1.98 cm/yr increase in diameter and .46-1.0 mm/yr increase in height. A72OTT01FCUS: fed upon by Coralliphila abbreviata and Hermodice caruncullata.

In a study of seven "massive" Caribbean corals, Soong (1993) identified major differences in reproductive behavior between species with large maximum colony size (>100 cm² in surface area), including Diploria strigosa, and species with small maximum colony size. The four large species studied broadcast gametes during a short spawning season and had a relatively large "puberty" size. The two smaller-sized and one medium-sized species brooded larvae during an extended season (year round in Panama) and had a puberty size of just 2 to 4 cm².

Prior to the early 1980s, for over 200 years, all corals were believed to be viviparous (brooding). It is now known that most reef-building corals release, or "broadcast", eggs and sperm into the water column during periodic and often synchronous spawning events. For decades researchers have speculated about and worked to identify environmental entrainment factors that might influence sexual reproduction and the eventual release of gametes. This synchronization is generally believed to operate on at least three interrelated temporal levels: (1) the time of the year; (2) the lunar cycle; and (3) the time of night. It is clear that nighttime is required for gamete release, but a consistent global relationship between lunar phase and the timing of spawning is less clear, given that most corals on the Great Barrier Reef in Australia spawn at neap tides, while the same species in southern Japan spawn at spring tides. It has seemed reasonable to assume that the time of the year for gamete release is linked to optimal sea surface temperature (SST). van Woesik et al. (2006), however, have argued that solar insolation (energy from the sun), is a better predictor of gamete production for many corals.They tested this hypothesis using data for 12 species of corals distributed throughout the Caribbean (tropical west Atlantic), including Diploria strigosa. Regarding temperature, they found that the cumulative dose of SST measured through time and the rate of change in temperature correlated poorly with the timing of coral spawning, although the average temperature during the month of spawning was significantly correlated with spawning. For solar insolation, they found that the rate of change and the cumulative response of solar insolation cycles was a better predictor of gamete release, although solar insolation intensity at the time of spawning was not. All of the coral species they examined showed highly significant positive relationships between spawning date and the cumulative dose of solar insolation, and 11 of 12 species, including D. strigosa, showed a significant response to the rate of change in solar insolation. Solar insolation and temperature are obviously related phenomena since solar irradiance ultimately drives SST, but because of the high specific heat capacity of water, maximum SST generally lags 1 to 2 months (or more) behind maximum solar insolation. Time delays in SST fluctuations are latitudinally predictable but vary with cloud-cover and windstrength. van Woesik et al. concluded that solar insolation influences the reproductive schedules of Caribbean corals, but water temperatures must be optimal (28–30 C) to allow maturation and gamete release. (van Woesik et al. 2006 and referencess therein)

Broadcast spawning by corals is a tightly synchronized process characterized by coordinated gamete release within 30 to 60 minute time windows once per year. Vize (2006) asserts that for shallow water corals, annual water temperature cycles set the month, lunar periodicity the day, and sunset time the hour of spawning. This tight temporal regulation is critical for achieving high fertilization rates in a pelagic environment. Given the differences in light and temperature that occur with depth and the importance of these parameters in regulating spawn timing, Vize notes that it has been unclear whether corals in deeper water can respond to the same environmental cues that regulate spawning behaviour in shallower coral. Vize used a remotely operated vehicle to monitor coral spawning activity (including that of Diploria strigosa) at the Flower Garden Banks (northwest Gulf of Mexico) at depths from 33 to 45 m, All recorded spawning events were within the same temporal windows as shallower conspecifics. These data indicate that deep corals at this location either sense the same environmental parameters, despite local attenuation, or communicate with shallower colonies that can sense such spawning cues.

In a study in Puerto Rico, D. strigosa spawned in August and/or September. Development of oocytes (egg-producing cells) began in October–November, between 5 and 7 months before spermatogenesis (sperm production). Development of spermaries (sperm-producing structures) started 6–7 months after oogenesis, in May to June. Spermatogenesis lasted 3 to 5 months, with sperm cells maturing rapidly and reaching full maturity at the same time as the eggs, in late July and August. A high proportion of colonies had mature spermatocytes and oocytes 4 days after the full moons of both July 28 and August 30, 1999, indicating that in the year of this study, a split spawning occurred. No mature gametes were found in these colonies in tissue samples collected in September of 1999. Spawning occurred after 11 p.m. on nights 9 and 10 after the full moon for D. strigosa. (47.6 and 50.03 eggs/polyp in 1999 and 2000, respectively). There was no significant correlation between colony size and mean polyp fecundity for D. strigosa. Even the smallest colonies sampled (140 cm²) were sexually mature, and there was high variability in fecundity; minimum reproductive size must therefore be below this size.

A85WYE01FCUS: hermaphroditic simultaneous. Oogenesis begins in late November and January, with gamete release in early September. A86SZM00FCUS: gametogenesis for females from mid-December to June and for males from June-July. Spawning season in mid-August with low reported recruitment rates.

D. strigosa reproduces sexually by a process called gametogenisis. They can also reproduce asexually by fragmentation. Moreover, they are hermaphrodites they are able to produce both male and female gametes. "D. strigosa uses the broadcast spawning method of fertilization; this is when the sperm and eggs combine in the water column or at the surface as opposed to brooding where fertilization occurs within the maternal polyp" (Evans, Wood, and Zeeh). Studies have shown that D. strigosas' spawning season occurs for a short time in mid August and spawning mainly occurs at night. Temperatures for peak fertilization are between 25 to 29 degrees Celsius and if the temperatures rise over 30 degrees Celsius larval developmental problems begin to occur" (Evans).

Bassim et al. (2002) studied the effects of water temperature on the reproduction of Diplora strigosa in the Flower Garden Banks reefs, a set of coral reefs in the northern Gulf of Mexico, ~110 miles offshore of Texas (U.S.A.): Although elevated seawater temperatures had no apparent effect on success of gametic fertilization in this species, the rate and progress of embryonic larval development were significantly negatively affected. Higher temperatures commonly produced numerous developmental aberrations during the development of the larvae. Thus, although fertilization rates can remain high under high temperature conditions, if temperatures remain high for several days, embryonic development and larval viability may be expected to decrease dramatically. The authors propose that the success of coral larval development may be diminished in areas where abnormally high sea surface temperatures occur during the spawning season.

United States

Rounded National Status Rank: NNR - Unranked

Rounded Global Status Rank: G4 - Apparently Secure

Reasons: Widespread distribution in the tropical western Atlantic but limited to reef communities. Moderately high sensitivity to eutrophication but lower sensitivity to sedimentation and salinity fluctuations.

Global Short Term Trend: Relatively stable (=10% change)

Comments: Information is needed on the status and trend of extant populations.

Degree of Threat: C : Not very threatened throughout its range, communities often provide natural resources that when exploited alter the composition and structure over the short-term, or communities are self-protecting because they are unsuitable for other uses

Comments: Considered less threatened due to low sensitivity to sedimentation but moderate sensitivity to eutrophication.

Biological Research Needs: Data needed on recruitment patterns and susceptibility to sedimentation.

Global Protection: Few to several (1-12) occurrences appropriately protected and managed

Comments: Numerous occurrences in the Florida Keys National Marine Sanctuary, Biscayne National Park and Dry Tortugas, Florida.

Needs: Mooring buoys need to be installed in marine protected areas.

Hetzinger et al. (2006) studied the geochemistry of the fast-growing Diploria strigosa, examining a 41-year record of geochemical variations. They were able to correlate specific geochemical changes in the coral with instrumental sea surface temperature (SST) on both monthly and mean annual time scales and with local air temperature on a mean annual scale.The geochemical coral proxies they used were highly correlated with annual and seasonal mean time series of major SST indices in the northern tropical Atlantic. Furthermore, the coral proxies capture the impact of the El Nino Southern Oscillation on the northern tropical Atlantic during boreal spring. Thus, Hetzinger et al. suggest that fast-growing Diploria strigosa corals are a promising new archive of historical climate data for the Atlantic Ocean.

Zamudio-Zamudio et al. (2003) analyzed the building materials used in the construction of building materials of the Fortress of San Juan de Ulua (16th century) and of the Portal de Miranda (18th century) in Veracruz City, Mexico. One of these materials, known as "mucara" stone, was analyzed by means of stereoscopic and scanning electron microscopy, X-ray diffraction, neutron activation, atomic absorption spectrometry, X-ray fluorescence, and thermogravimetry and was identified as the skeleton of the coral Diploria strigosa, whose main component is the mineral aragonite (a crytal form of calcium carbonate, CaCO₃). Many of the buildings in Veracruz City were built with mucara stone (Zamudio-Zamudio et al. 2003 and references therein).