Larval supply to a marine reserve and adjacent fished area in the Soufrière Marine Management Area, St Lucia, West Indies

A total of 76 reef fish species from 31 families was collected at two coral reef sites, one in a marine reserve and the other in an adjacent fished area of the Soufrière Marine Management Area (SMMA) in St. Lucia. Five families (Scaridae, Pomacentridae, Synodontidae, Apogonidae and Blennidae) dominated the collections at both sites while species of high commercial value were rare. Monthly patterns of larval supply differed among selected species, but overall trends were similar between the two sites for most species. However, despite the geographical proximity of the two sites, the fished area received a consistently higher abundance and diversity of larvae than the marine reserve throughout the study period. Patterns in larval supply generally were reflected in the settlement patterns of Stegastes partitus. Results suggest that local-scale variation in hydrodynamic and or biological features is influencing the arrival and hence settlement of larvae at the reef.     

The effects of age and size on habitat selection during settlement of a damselfish

The adults of many coral reef fish species are site-attached, and their habitat is selected at the time of settlement by their larvae. The length of the planktonic larval period varies both intra- and interspecifically, and it is unknown how the age and size of larvae may affect their selection of habitat. To investigate the influence of age and size on habitat selection, I collected newly settled Hawaiian domino damselfish, Dascyllus albisella, daily from grids containing three coral species at four locations in Kaneohe Bay, Oahu, Hawaii. I recorded the coral species each fish was collected on, and measured and aged (by otoliths) the collected fish. The results indicate that the coral Pocillopora meandrina was selected by settling fish significantly more than the other two coral species. Younger and smaller larvae selected this coral species more frequently than older/larger larvae. In addition, younger/smaller individuals were found more commonly inside the bay than older/larger settling larvae. Differences in the choice of coral species and location of settlement may be partly due to ontogenetic differences in the sensory capacities of larvae to detect corals, conspecifics, and predators, or to a larval competency period. This revised version was published online in July 2006 with corrections to the Cover Date.     

Early life history and settlement of the slender filefish, <Emphasis Type="Italic">Monacanthus tuckeri</Emphasis> (Monacanthidae), at Calabash Caye,Turneffe Atoll,Belize

Synopsis We examined early life history traits and patterns of settlement of the slender filefish, Monacanthus tuckeri, at Calabash Caye, Turneffe Atoll, Belize. A settlement peak was evident at the new moon, and no settlement occurred at the full moon. However, settlement rates at the quarter moons could not be estimated due to sampling gaps. Many reef fishes show new moon settlement peaks, so M. tuckeri shares some characteristics with the primarily perciform species on coral reefs. Pelagic larval duration was long (mean = 42 days) and variable, suggesting that dispersal patterns might be diverse. Size at settlement was large (mean = 32 mm total length) and also variable. Larval duration and size at settlement were outside of the average values exhibited by reef fishes, but are not beyond the extreme end of the range, and might be explained by association with pelagic debris prior to settlement. There were no differences in overall settlement rates on reef and seagrass habitats, and fish settling to either habitat did not differ in larval duration, size at settlement, or larval growth rate. This suggests that settlement to alternative habitats may be random, or driven by availability of suitable microhabitat, rather than habitat quality or individual traits.     

Spatio-temporal patterns of recruitment of labroid fishes (Pisces: Labridae and Scaridae) to damselfish territories

Recent studies have shown that recruitment variability is an important process structuring reef fish assemblages. The aim of this study is to describe the spatio-temporal patterns of recruitment of three abundant labroid taxa (Coris schroederi, Halichoeres melanurus and Scarus spp.), using damselfish territories as replicate units of habitat. Temporal recruitment patterns of each taxa were consistent among three sites along 2 km of reef tract, with small differences among sites probably the result of hydrological or random factors operating at that scale. Recruitment of only one species (C. schroederi) showed consistent differences in the magnitude of recruitment among sites, which was probably due to an overriding effect of habitat selection for the location of the territories on the reef profile at one site. Two taxa, C. schroederi and Scarus spp., recruited in low to moderate rates over many weeks with moderate recruitment peaks detected in one year only. This pattern may be characteristic of many labroid species that have protracted periods of production of larvae. In contrast, H. melanurus recruited in a single short pulse of high magnitude each summer, which suggests that production of larvae by this species may occur over a more restricted period of time. No strong pattern of lunar entrainment of recruitment was detected for any taxa, which may be due to a lack of lunar periodicity in production of larvae. Further studies are now required to identify the processes that are important in determining patterns of labroid recruitment. This revised version was published online in August 2006 with corrections to the Cover Date.     

Shifting ecological baselines and the demise of Acropora cervicornis in the western North Atlantic and Caribbean Province: a Pleistocene perspective

 In recent years, marine scientists have become increasingly alarmed over the decline of live coral cover throughout the Caribbean and tropical western Atlantic region. The Holocene and Pleistocene fossil record of coral reefs from this region potentially provides a wealth of long-term ecologic information with which to assess the historical record of changes in shallow water coral reef communities. Before fossil data can be applied to the modern reef system, critical problems involving fossil preservation must be addressed. Moreover, it must be demonstrated that the classic reef coral zonation patterns described in the early days of coral reef ecology, and upon which “healthy” versus “unhealthy” reefs are determined, are themselves representative of reefs that existed prior to any human influence. To address these issues, we have conducted systematic censuses of life and death assemblages on modern “healthy” patch reefs in the Florida reef tract that conform to the classic Caribbean model of reef coral zonation, and a patch reef in the Bahamas that is currently undergoing a transition in coral dominance that is part of a greater Caribbean-wide phenomenon. Results were compared to censuses of ancient reef assemblages preserved in Pleistocene limestones in close proximity to each modern reef. We have determined that the Pleistocene fossil record of coral reefs may be used to calibrate an ecological baseline with which to compare modern reef assemblages, and suggest that the current and rapid decline of Acropora cervicornis observed on a Bahamian patch reef may be a unique event that contrasts with the long-term persistence of this taxon during Pleistocene and Holocene time. Accepted: 19 May 1998     

珊瑚礁生态修复研究进展

珊瑚礁生态系统有着很高的生物多样性和重要的生态功能。20世纪80年代以后全球范围内珊瑚礁的大面积退化引起了人们广泛的关注。简述了世界珊瑚礁资源现状,破坏原因,生态修复方法以及我国的珊瑚礁资源现状和修复策略等。国际上通用的生态修复策略主要是根据珊瑚的两种繁殖方式进行的,此外再配合人为的适度干扰,增加珊瑚的成活率。方法主要有：珊瑚移植、Gardening、人工渔礁、底质稳固、幼体附着等以及对相关利益者的宣传,海岸带的保护等。我国珊瑚礁退化严重,但是由于缺乏相关的科技资料报道和技术支持,缺乏系统的研究,使得珊瑚礁的生态修复成绩甚微,今后应在该领域开展更多的工作。     

A dynamic model of group-size choice in the coral reef fish Dascyllus albisella

We developed a dynamic programming model of group size choicefor settlingcoral reef fish to help understand variabilityin observed group sizes. Ratherthan calculating optimal groupsize, we modeled optimal choice and calculatedthe acceptablegroup sizes that arose from this choice. In the model, settlingindividualsweigh the fitness value of settling in a group against theexpectedfitness of searching another day and encountering other groups,choosingthe option with the higher value. Model results showed thatindividualssettling on any given day in the settling season have severalacceptablegroup sizes in which they can settle. The range of acceptablegroupsizes also changes across the season. Early in the season,when there is stilladequate time to grow, large groups (withhigher survival) have the highestfitness. Late in the season,when the ability to grow fast becomes moreimportant, smallgroups, which convey fast growth rates (although riskier),havehigher fitness. Thus, according to our model, even when fishall make thesame, simple decisions, a variety of outcomes arepossible, depending on thespecific options encountered andtemporally changing ecological pressures.Even when all fishbehave optimally, initial variability in group sizes willpersist.     

Changes in Coral Reef Communities and an Associated Reef Fish Species, <Emphasis Type="Italic">Cephalopholis cruentata</Emphasis> (Lacépède), After 30 years on Curaçao (Netherlands Antilles)

Using the same methodology and identical sites, we repeat a study dating from 1973 and quantify cover of hard coral species, soft corals, sponges, hard substratum and soft substratum, and density of a commercially important reef fish species, the graysby Cephalopholis cruentata, along a depth-gradient of 3–36 m on the coral reefs of Curaçao. The objective was to determine the multi-decade change in benthic coral reef cover and structural complexity, and their effect on densities of an associated reef fish species. Total hard coral cover decreased on average from 52% in 1973 to 22% in 2003, representing a relative decline of 58%. During this time span, the cover of hard substratum increased considerably (from 11 to 58%), as did that of soft corals (from 0.1 to 2.2%), whereas the cover of sponges showed no significant change. Relative decline of hard coral cover and of reef complexity was greatest in shallow waters (near the coast), which is indicative of a combination of anthropogenic influences from shore and recent storm damage. Cover of main reef builder coral species (Agaricia spp., Siderastrea siderea, Montastrea annularis) decreased more than that of other species, and resulted in a significant decrease in reef complexity. Although density of C. cruentata was highly correlated to cover of Montastrea and Agaricia in 1973, the loss of coral cover did not show any effect on the total density of C. cruentata in 2003. However, C. cruentata showed a clear shift in density distribution from shallow water in 1973 to deep water in 2003. It can be concluded that the reefs of Curaçao have degraded considerably in the last three decades, but that this has had no major effect on the population size of one commercially important coral-associated fish species.