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Notes: Abstract  Experimental carbonate blocks of coral skeleton, Porites lobata (PL), and cathedral limestone (LS) were deployed for 14.8 months at shallow (5–6 m) and deep (11–13 m) depths on a severely bioeroded coral reef, Champion Island, Galápagos Islands, Ecuador. Sea urchins (Eucidaris thouarsii) were significantly more abundant at shallow versus deep sites. Porites lobata blocks lost an average of or 60.5% decrease Losses did not vary significantly at depths tested. Internal bioeroders excavated an average or 0.6% decrease while external bioeroders removed an average of few encrusting organisms were observed on the PL blocks. Cathedral limestone blocks lost an average of or 4.6% decrease also with no relation to depth. Internal bioeroders excavated an average of and external bioeroders removed an average of or 3.9% decrease from the LS blocks. Most (57.6%) encrustation occurred on the bottom of LS blocks, and there was more accretion on block bottoms in deep versus shallow sites. External bioerosion reduced the average height of the reef framework by for hard substrata (represented by LS) and for soft substrata (represented by PL). The results of this study suggest that coral reef frameworks in the Galápagos Islands are in serious jeopardy. If rates of coral recruitment do not increase, and if rates of bioerosion do not decline, coral reefs in the Galápagos Islands could be eliminated entirely.

Notes: Abstract Experimental carbonate blocks of coral skeleton,Porites lobata (PL), and cathedral limestone (LS) were deployed for 14.8 months at shallow (5–6 m) and deep (11–13m) depths on a severely bioeroded coral reef, Champion Island, Galápagos Islands, Ecuador. Sea urchins (Eucidaris thouarsii) were significantly more abundant at shallow versus deep sites.Porites lobata blocks lost an average of 25.4 kg m−2yr−1 (23.71 m−2yr−1 or 60.5% decrease yr−1). Losses did not vary significantly at depths tested. Internal bioeroders excavated an average of 2.6 kg m−2 yr−1 (2.41 m−2 yr−1 or 0.6% decrease yr−1), while external bioeroders removed an average of 22.8 kg m−2 yr−1). (21.31 m−2 yr−1). or 59.9% decrease yr−1). few encrusting organisms were observed on the PL blocks. Cathedral limestone blocks lost an average of 4.1 kg m−2 yr−1). (1.81 m−2 yr−1). or 4.6% decrease yr-'), also with no relation to depth. Internal bioeroders excavated an average of 0.6 kg m−2 yr−1). (0.31 m−2 yr−1). or 0.7% decrease yr−1). and external bioeroders removed an average of 3.5 kg m−2 yr−1). (1.51 m−2 yr−1). or 3.9% decrease yr−1). from the LS blocks. Most (57.6%) encrustation occurred on the bottom of LS blocks, and there was more accretion on block bottoms in deep (61.4 mg cm−2 yr−1). versus shallow (35.0 mg cm−2 yr−1) sites. External bioerosion reduced the average height of the reef framework by 0.2 cm yr−1). for hard substrata (represented by LS) and 2.3 cm yr−1). for soft substrata (represented by PL). The results of this study suggest that coral reef frameworks in the Galápagos Islands are in serious jeopardy. If rates of coral recruitment do not increase, and if rates of bioerosion do not decline, coral reefs in the Galápagos Islands could be eliminated entirely.

Notes: Abstract A comparative study of the reproductive ecology of the zooxanthellate, scleractinian corals Porites lobata Dana and P. panamensis Verrill was conducted from 1985 to 1991 in eastern Pacific reef environments that were severly impacted by the 1982–1983 El Niño warming events. P. lobata, a presumed broadcast spawner of large colony size, is widely distributed in the equatorial eastern Pacific, whereas P. panamensis, a brooder of small colony size, is abundant only on some reefs in Panamá. Both species were gonochoric with nearly 1:1 sex ratios in large study populations except for P. lobata at Caño Island that had 14% hermaphroditic colonies. Mature, unfertilized oocytes contained numerous zooxanthellae in both Porites species, and all planula developmental stages contained zooxanthellae in P. panamensis. Year-round sampling revealed high proportions of colonies with gonads, ranging from 30 to 68% in P. lobata and from 60 to 68% in P. panamensis. No clear relationship between numbers of reproductive colonies and the thermal stability of the habitat was evident in P. lobata: percent colonies with gonads at non-upwelling sites was 48 to 68% at Caño Island (Costa Rica) and Uva Island (Panamá), and at upwelling sites 30 to 50% at Saboga Island and Taboga Island (Panamá), and the Galápagos Islands (Ecuador). Similarly, 90% of all P. panamensis colonies were reproductive at Uva Island (a non-upwelling site), and 86% were reproductive at Taboga Island (an upwelling site). Upwelling at Taboga Island is seasonal, nevertheless P. panamensis produced mature gonads or planulae over most of the year (11 mo), whereas P. lobata exhibited reproductive activity during only 2 mo (May and June). No clear lunar periodicity was observed in P. panamensis (Taboga Island), but a high proportion of P. lobata showed increased gonadal development around full and new moon, especially at Caño and Uva Islands. Estimated fecundities were relatively high for P. lobata at Caño (4000 eggs cm-2 yr-1) and Uva (5200 eggs cm-2 yr-1) Islands, and notably low (70 to 110 eggs cm-2 yr-1) in the Galápagos Islands. P. panamensis mean fecundity at Taboga Island was 720 planulae cm-2 yr-1 or 4.0 mm3 cm-2 yr-1, which was lower than the egg volume production of P. lobata at Caño and Uva Islands (7.0 to 10.0 mm3 cm-2 yr-1). The capacity of P. lobata and P. panamensis to reproduce sexually supports the notion that eastern Pacific coral reef recovery may not be dependent on long-distance dispersal from central Pacific areas. However, sexual recruits of P. lobata are absent or uncommon at all eastern Pacific study sites while recruits of P. panamensis were common to abundant only at the Uva Island study site. Asexual fragmentation in P. lobata augments recruitment locally, but plays no role in P. panamensis recruitment.