Translating the 10 golden rules of reforestation for coral reef restoration

Efforts are accelerating to protect and restore ecosystems globally. With trillions of dollars in ecosystem services at stake, no clear framework exists for developing or prioritizing approaches to restore coral reefs even as efforts and investment opportunities to do so grow worldwide. Restoration may buy time for climate change mitigation, but it lacks rigorous guidance to meet objectives of scalability and effectiveness. Lessons from restoration of terrestrial ecosystems can and should be rapidly adopted for coral reef restoration. We propose how the 10 golden rules of effective forest restoration can be translated to accelerate efforts to restore coral reefs based on established principles of resilience, management, and local stewardship. We summarize steps to undertake reef restoration as a management strategy in the context of the diverse ecosystem service values that coral reefs provide. Outlining a clear blueprint is timely as more stakeholders seek to undertake restoration as the UN Decade on Ecosystem Restoration begins.     

Connectivity or demography: Defining sources and sinks in coral reef fish metapopulations

The identity of an individual patch as a source or a sink within a metapopulation is a function of its ability to produce individuals and to disperse them to other patches. In marine systems patch identity is very often defined by dispersal ability alone—upstream patches are sources—while issues of variable habitat quality (which affects local production) are ignored. This can have important ramifications for the science of marine reserve siting. This study develops a spatially explicit source–sink metapopulation model for reef fish and uses it to evaluate the relative importance of connectivity versus demography and how this depends upon the level of local larval retention and the strength of density-dependent recruitment. Elasticity analyses indicated that patch contribution (source or sink) was more sensitive to demographic parameters (particularly survival) than connectivity and this effect was conserved even under strong levels of density-dependence and was generally strengthened as local retention increased. Variability in the relationship between parameter elasticity and local retention was shown to be dependent upon the magnitude of connectivity for an individual patch relative to a critical connectivity value. The proportion of larvae lost due to transport processes was an important parameter which directly affected the magnitude of this critical connectivity value. Patches with connectivity values less than the critical value contributed to the metapopulation largely via production (i.e., local demographics most important). As local retention increased, so did the importance of demographic parameters in these patches. Patches with connectivity values greater than the critical value contributed largely via dispersal of larvae and thus the importance of local demographics decreased as local retention increased.     

An agent-based model for simulating trading of multi-species fisheries quota

Individual transferable quotas (ITQs) are increasingly seen as a way to make fisheries more profitable and halt over-capitalisation. ITQs allocate to users of a resource a share of a total allowable catch (TAC) which they are free to use, lease, or sell. We outline an approach to modelling the effect of an ITQ system in a multi-species, multi-sector fishery and apply it to the Coral Reef Fin Fish Fishery (CRFFF) in Queensland, Australia. An ITQ model, based on the assumption that operators seek to maximize profits, simulates the use of tradeable quota units by operators in the fishery, taking account of the initial quota allocation to operators, seasonal fish prices and individual operator variable costs, their fishing efficiency and experience, and constraints on vessel movements. Rationalization of the fishery is predicted to occur under an ITQ system for the CRFFF, which will lead to reductions in effort, increases in profits, and changes over time in quota prices. The ecological consequences of transferable quota in the multi-species fishery are seen in the catch and discard levels of the less profitable species, even though a TAC was set. This had flow-on effects on biomass. For example, simulations showed that the TAC for the primary target species, coral trout, was used more fully than that for a less valuable target species, red throat emperor, and that this was achieved through increased discarding of red throat emperor. Catches of both coral trout and red throat emperor that were derived from the model were higher than those recently observed in the fishery. The effort predicted by the model, however, closely approximated the actual effort observed in the fishery following implementation of ITQ management.     

A Global Baseline for Spawning Aggregations of Reef Fishes

Abstract: Species that periodically and predictably congregate on land or in the sea can be extremely vulnerable to overexploitation. Many coral reef fishes form spawning aggregations that are increasingly the target of fishing. Although serious declines are well known for a few species, the extent of this behavior among fishes and the impacts of aggregation fishing are not appreciated widely. To profile aggregating species globally, establish a baseline for future work, and strengthen the case for protection, we (as members of the Society for the Conservation of Reef Fish Aggregations) developed a global database on the occurrence, history, and management of spawning aggregations. We complemented the database with information from interviews with over 300 fishers in Asia and the western Pacific. Sixty‐seven species, mainly commercial, in 9 families aggregate to spawn in the 29 countries or territories considered in the database. Ninety percent of aggregation records were from reef pass channels, promontories, and outer reef‐slope drop‐offs. Multispecies aggregation sites were common, and spawning seasons of most species typically lasted <3 months. The best‐documented species in the database, the Nassau grouper (Epinephelus striatus), has undergone substantial declines in aggregations throughout its range and is now considered threatened. Our findings have important conservation and management implications for aggregating species given that exploitation pressures on them are increasing, there is little effective management, and 79% of those aggregations sufficiently well documented were reported to be in decline. Nonetheless, a few success stories demonstrate the benefits of aggregation management. A major shift in perspective on spawning aggregations of reef fish, from being seen as opportunities for exploitation to acknowledging them as important life‐history phenomena in need of management, is urgently needed.     

涠洲岛珊瑚礁分布特征与环境保护的初步研究

根据历年来对涠洲岛珊瑚礁所观测的资料,初步研究了该岛珊瑚的种群结构及其分布特征,以及珊瑚礁的形成及发育过程,并提出了涠洲岛珊瑚的保护措施.      

Possible Use of Ash Residues for the Construction of Artificial Reefs at Sea

Utilization of ash residues, including coal ash, oil ash, and municipal solid waste combustion ash, for the construction of artificial reefs at sea has been investigated by many researchers throughout the world for nearly 20 years. Both laboratory and field studies have shown that an artificial reef made of stabillized ash-concrete (SAC) has had no adverse effect on the marine environment. Indeed, published studies have shown that fish counts increase around SAC reefs owing to an abundance of colonizing organisms and to protection provided by cavities within the reef structures. However, public and regulatory resistance to the use of SAC for artificial reef construction at sea is still very strong in certain countries due to concern for possible negative environmental impacts, primarily in the area of bioaccumulation of elements or compounds originating from the ash component of SAC.

In this paper, technological feasibility of using ash residues for artificial reef construction is presented, based on the available 20 years of scientific data, including engineering workability, physical integrity, chemical leaching potential and biological effects. More important, we also identify conceptual barriers for the acceptance of using SAC for the construction of ocean reefs and suggest approaches to overcome these barriers.     

Viability Analysis of Reef Fish Populations Based on Limited Demographic Information

Abstract:  Marine protected areas (MPAs) that allow some degree of artisanal fishing have been proposed to control the overexploitation of marine resources while allowing extraction by local communities. Nevertheless, the management of MPAs is often impaired by the absence of data on the status of their resources. We devised a method to estimate population growth rates with the type of data that are usually available for reef fishes. We used 7 years of spatially explicit abundance data on the leopard grouper ( Mycteroperca rosacea ) in an MPA in the Gulf of California, Mexico, to construct a matrix population model that incorporated the effects of El Niño/La Niña Southern Oscillation on population dynamics. An environmental model that estimated different demographic estimates for El Niño and La Niña periods performed better than a single-environment model, and a single-habitat model performed better than a model that considered different depths as different habitats. Our results suggest that the population of the leopard grouper off the main island of the MPA is not viable under present conditions. Although the impact of fishing on leopard grouper populations in the MPA has not yet been established, fishing should be closed as a precautionary measure at this island if a priority of the MPA is to ensure the sustainability of its fish populations.     

Lag Effects in the Impacts of Mass Coral Bleaching on Coral Reef Fish, Fisheries, and Ecosystems

Abstract:  Recent episodes of coral bleaching have led to wide-scale loss of reef corals and raised concerns over the effectiveness of existing conservation and management efforts. The 1998 bleaching event was most severe in the western Indian Ocean, where coral declined by up to 90% in some locations. Using fisheries-independent data, we assessed the long-term impacts of this event on fishery target species in the Seychelles, the overall size structure of the fish assemblage, and the effectiveness of two marine protected areas (MPAs) in protecting fish communities. The biomass of fished species above the size retained in fish traps changed little between 1994 and 2005, indicating no current effect on fishery yields. Biomass remained higher in MPAs, indicating they were effective in protecting fish stocks. Nevertheless, the size structure of the fish communities, as described with size-spectra analysis, changed in both fished areas and MPAs, with a decline in smaller fish (<30 cm) and an increase in larger fish (>45 cm). We believe this represents a time-lag response to a reduction in reef structural complexity brought about because fishes are being lost through natural mortality and fishing, and are not being replaced by juveniles. This effect is expected to be greater in terms of fisheries productivity and, because congruent patterns are observed for herbivores, suggests that MPAs do not offer coral reefs long-term resilience to bleaching events. Corallivores and planktivores declined strikingly in abundance, particularly in MPAs, and this decline was associated with a similar pattern of decline in their preferred corals. We suggest that climate-mediated disturbances, such as coral bleaching, be at the fore of conservation planning for coral reefs.     

Effects of Customary Marine Closures on Fish Behavior,Spear‐Fishing Success,and Underwater Visual Surveys

Abstract: Customary management systems (i.e., management systems that limit the use of marine resources), such as rotational fisheries closures, can limit harvest of resources. Nevertheless, the explicit goals of customary management are often to influence fish behavior (in particular flight distance, i.e., distance at which an organism begins to flee an approaching threat), rather than fish abundance. We explored whether the flight distance of reef fishes targeted by local artisanal fishers differed between a customary closure and fished reefs. We also examined whether flight distance of these species affected fishing success and accuracy of underwater visual census (UVC) between customary closed areas and areas open to fishing. Several species demonstrated significant differences in flight distance between areas, indicating that fishing activity may increase flight distance. These relatively long flight distances mean that in fished areas most target species may stay out of the range of spear fishers. In addition, mean flight distances for all species both inside and outside the customary‐closure area were substantially smaller than the observation distance of an observer conducting a belt‐transect UVC (mean [SE]= 8.8 m [0.48]). For targeted species that showed little ability to evade spear fishers, customary closures may be a vital management technique. Our results show that customary closures can have a substantial, positive effect on resource availability and that conventional UVC techniques may be insensitive to changes in flight behavior of fishes associated with fishing. We argue that short, periodic openings of customary closures may allow the health of the fish community to be maintained and local fishers to effectively harvest fishes.