Sexual recruitment of the corals Favia fragum and Agaricia humilis in a 30‐m³ exhibit aquarium: species‐specific limitations and implications on reproductive ecology

Abstract

We studied the recruitment of the Caribbean reef building corals Favia fragum (F. fragum) and Agaricia humilis(A. humilis) in captivity. Thirty colonies of each species collected in Curaçao, Netherlands Antilles, reproduced sexually during a temporary stay in a 30-m(3) closed system from November 2001-January 2002. Twelve months later, the F1 generation of F. fragum started reproducing and formed an F2 generation. No reproduction of the F1 recruits of A. humilis was observed. Two years after the introduction of the field colonies, sexual recruits of both species were assessed using two different methods: recruits were estimated using quadrats (quadrat sampling method) and the total number of recruits was counted by creating a map of the artificial rock work divided in distinct areas (area census method). Recruitment rates of F. fragum were highest for the F2 generation on horizontal surfaces (area census method: 137.9+/-191.7 recruits m(-2); quadrat sampling method: 272.0+/-254.8 recruits m(-2); mean+/-SD) and were overall lowest for the F1 generation on overhanging areas of the tank (area census method: 3.8+/-4.0 recruits m(-2); quadrat sampling method: 4.0+/-6.1 recruits m(-2); mean+/-SD recruits m(-2)). The populations of both species showed similar patterns independent of the applied assessment method with highest densities on horizontal surfaces followed by vertical surfaces and lowest densities on overhanging surfaces; however, both methods showed conflicting results when the influence of the surface orientation on the population densities was statistically analyzed. The maximum density of A. humilis (1.4+/-2.7 recruits m(-2) on horizontal surfaces) was much lower than the maximum density of the F1 generation of F. fragum (24.7+/-18.3 recruits m(-2)). Colony sizes of recruits within each population (F. fragum F1: 3.12+/-0.98 cm, F2: 0.83+/-0.41 cm; A. humilis F1: 3.79+/-1.35 cm; maximum diameter+/-SD) did not differ between different orientations (horizontal vs. vertical vs. overhanging). Calculated growth rates in the aquarium reflected those observed for F. fragum in the field, whereas A. humilis showed slower growth in the aquarium than in the field. Factors such as competition, sedimentation, and predation, that generally reduce in situ recruitment may be excluded in captivity resulting in far higher recruitment rates. This study confirms that aquarium exhibits can serve as a comparative model to study the ecology of corals under semi-controlled conditions. Zoo Biol 0:1-17, 2007. (c) 2007 Wiley-Liss, Inc.

Sexual reproduction of scleractinian corals in public aquariums: current status and future perspectives

“…In addition, colonies of Fa. fragum in an exhibit tank at Rotterdam Zoo (where reproduction was not manipulated) produced more than 100 juveniles which managed to establish in the systems (D. Petersen, M. Laterveer & G. Visser, in press).…”

“…fragum and Ag. humilis , at the Rotterdam Zoo have shown that when settlement is not manipulated larval behaviour between species can differ significantly and may therefore lead to very low recruitment rates or none at all (D. Petersen, M. Laterveer & G. Visser, in press).…”

Trans-Atlantic rafting by the brooding reef coral Favia fragum on man-made flotsam

“…They have been estimated to grow 16 mm in diameter per year in a growth range from 11 to 27 mm (Van Moorsel 1988). They have a fast generation turnover and can become fertile within 1 yr, implying that they reach maturity when they are still very small with even marginal polyps able to produce gonads (Soong & Lang 1992, Petersen et al 2007. The maximum corallum size in F. fragum is smaller (<10 cm) in comparison with many other Atlantic coral species and appears to be related to its reproductive strategy as a brooder (Vaughan 1916, Soong 1993.…”

“…They are initially phototaxic but become rapidly negatively buoyant and settle on dark surfaces in clusters close to their parents (Lewis 1974a,b, Carlon & Olson 1993, Carlon 2002, Petersen et al 2007, Norström & Sandström 2010. They prefer horizontal, flat, uneven surfaces for settlement (Petersen et al 2005a(Petersen et al ,b, 2007.…”

Reclutamiento del coral Acropora palmata sobre sustratos de dos materiales

“…Estas preferencias dependen de las condiciones ambientales a las que se someten, así como la especie de coral involucrada (Petersen et al 2005(Petersen et al , 2007bSzmant & Miller 2006, Arnold & Steneck 2011, Davies et al 2013. Los materiales que se han utilizado para el reclutamiento coralino son carbonato de calcio, plástico, concreto, granito, acero, gabro, arenisca ('sandstone'), esqueleto de coral, terracota, madera, cerámica, caolinita y algas coralinas incrustantes (Petersen et al 2005, Creed & De Paula 2007, Burt et al 2009, Ritson-Williams et al 2010, Mason et al 2011, Salinas-de-León et al 2011.…”