Nanette E. Chadwick-Furman

Growth and population dynamic model of the reef coral Fungia granulosa Klunzinger, 1879 at Eilat, northern Red Sea.

The lack of population dynamic information for most species of stony corals is due in part to their complicated life histories that may include fission, fusion and partial mortality of colonies, leading to an uncoupling of coral age and size. However, some reef-building corals may produce compact upright or free-living individuals in which the above processes rarely occur, or are clearly detectable. In some of these corals, individual age may be determined from size, and standard growth and population dynamic models may be applied to gain an accurate picture of their life history. We measured long-term growth rates (up to 2.5 years) of individuals of the free-living mushroom coral Fungia granulosa Klunzinger, 1879 at Eilat, northern Red Sea, and determined the size structure of a population on the shallow reef slope. We then applied growth and population models to the data to obtain estimates of coral age, mortality rate, and life expectancy in members of this species. In the field, few F. granulosa polyps suffered partial mortality of >10% of their tissues. Thus, the majority of polyps grew isometrically and determinately, virtually ceasing growth by about 30-40 years of age. Coral ages as revealed by skeletal growth rings were similar to those estimated from a growth curve based on field data. The frequency of individuals in each age class on the reef slope decreased exponentially with coral age, indicating high mortality rates when corals were young. The maximum coral age observed in the field population (31 years) was similar to that estimated by application of a population dynamic model (30 years). Calculated rates of growth, mortality and life expectancy for F. granulosa were within the range of those known for other stony corals. Our results reveal a young, dynamic population of this species on Eilat reefs, with high turnover rates and short lifespans. Such information is important for understanding recovery of coral reefs from disturbances, and for application to the management of commercially exploited coral populations.

Experimental fragmentation reduces sexual reproductive output by the reef-building coral Pocillopora damicornis

Abstract Natural and anthropogenic disturbances may fragment stony reef corals, but few quantitative data exist on the impacts of skeletal fragmentation on sexual reproduction in corals. We experimentally fragmented colonies of the branching coral Pocillopora damicornis and determined the number and size of planula larvae released during one lunar reproductive cycle. Partially fragmented colonies significantly delayed both the onset and peak period of planula release compared with intact control colonies. Most fragments removed from the corals died within 11–18 days, and released few planulae. The total number of planulae released per coral colony varied exponentially with remaining tissue volume, and was significantly lower in damaged versus undamaged colonies. However, the number of planulae produced per unit tissue volume, and planula size, did not vary with damage treatment. We conclude that even partial fragmentation of P. damicornis colonies (<25% of tissue removed) decreases their larval output by reducing reproductive tissue volume. Repeated breakage of corals, such as caused by intensive diving tourism or frequent storms, may lead to substantially reduced sexual reproduction. Therefore, reef management should limit human activities that fracture stony corals and lead to decreases in colony size and reproductive output.

Effects of Coral Reef Attribute Damage on Recreational Welfare

This paper presents the results of an economic valuation of coral reef degradation at Eilat, Israeli Red Sea. We estimate the marginal prices of coral and fish diversity and water visibility at US

Dose-response modeling of recreationally important coral-reef attributes: a review and potential application to the economic valuation of damage

2.60 and US

Coral recruitment: a spatio-temporal analysis along the coastline of Eilat, northern Red Sea

1.20 per dive, respectively. From the standpoint of recreational diving welfare, the annual social costs of activities contributing to coral reef degradation are approximately US

Coral cover and partial mortality on anthropogenically impacted coral reefs at Eilat, northern Red Sea

2.86 million. To our knowledge, this is the first economic valuation of individual coral reef attributes and the first application of a choice experiment to coral reef valuation.

Abundance and clonal replication in the tropical corallimorpharian Rhodactis rhodostoma

Abstract.Dose–response modeling has been widely used to document links between anthropogenic stressors and ecosystem attributes, and as a basis in the economic valuation of pollution damage. We review studies on the relation between anthropogenic stress factors and coral-reef attributes valuable in recreation, discuss the components of the economic value of coral reefs, and examine the potential use of dose–response functions in the economic valuation of coral-reef damage.