Dynamics of larval fish and zooplankton in selected south and west coast estuaries of South Africa

Larval fish and zooplankton assemblages were studied in nine south and west coast estuaries in the cool-temperate and the cool/warm-temperate boundary region between June 2003 and March 2004. This study served to provide new information on previously unstudied estuaries and expand on existing knowledge of larval fish and zooplankton assemblages associated with various estuary types. The south and west coast estuaries sampled in this study showed lower salinities (12.2 - 13.7), lower water temperatures (14.5 - 16.9 °C) and higher turbidities (k = 0.02 - 0.04) in winter and spring while higher salinities (21.7 - 21.8), higher water temperatures (21.7 - 23.1°C) and lower turbidities (k 20 orders and >35 families. The copepod Pseudodiaptomus hessei dominated (59 %) the zooplankton and occurred in similar densities to those observed in other South African estuaries. Larval fish and zooplankton varied across seasons, peaking simultaneously in summer although zooplankton showed additional density peaks during the closed phase of some estuaries. Both plankton components were more abundant in the oligohaline and mesohaline zones within the estuaries. Freshwater input, estuary type and the biogeography of the area influenced the composition and structure of larval fish and zooplankton assemblages in these estuaries. The findings suggest that the estuaries are functioning as successful breeding areas for the larvae of endemic estuary-resident fish species and that these estuaries have to be managed to ensure an adequate freshwater supply to maintain the biological integrity of the ecosystem, specially the maintenance of the highly productive River-Estuary Interface (REI) regions

Large-scale coral reef restoration could assist natural recovery in Seychelles, Indian Ocean

The aim of ecological restoration is to establish self-sustaining and resilient systems. In coral reef restoration, transplantation of nursery-grown corals is seen as a potential method to mitigate reef degradation and enhance recovery. The transplanted reef should be capable of recruiting new juvenile corals to ensure long-term resilience. Here, we quantified how coral transplantation influenced natural coral recruitment at a large-scale coral reef restoration site in Seychelles, Indian Ocean. Between November 2011 and June 2014 a total of 24,431 nursery-grown coral colonies from 10 different coral species were transplanted in 5,225 m2 (0.52 ha) of degraded reef at the no-take marine reserve of Cousin Island Special Reserve in an attempt to assist in natural reef recovery. We present the results of research and monitoring conducted before and after coral transplantation to evaluate the positive effect that the project had on coral recruitment and reef recovery at the restored site. We quantified the density of coral recruits (spat <1 cm) and juveniles (colonies 1-5 cm) at the transplanted site, a degraded control site and a healthy control site at the marine reserve. We used ceramic tiles to estimate coral settlement and visual surveys with 1 m2 quadrats to estimate coral recruitment. Six months after tile deployment, total spat density at the transplanted site (123.4 ± 13.3 spat m-2) was 1.8 times higher than at healthy site (68.4 ± 7.8 spat m-2) and 1.6 times higher than at degraded site (78.2 ± 7.17 spat m-2). Two years after first transplantation, the total recruit density was highest at healthy site (4.8 ± 0.4 recruits m-2), intermediate at transplanted site (2.7 ± 0.4 recruits m-2), and lowest at degraded site (1.7 ± 0.3 recruits m-2). The results suggest that large-scale coral restoration may have a positive influence on coral recruitment and juveniles. The effect of key project techniques on the results are discussed. This study supports the application of large-scale, science-based coral reef restoration projects with at least a 3-year time scale to assist the recovery of damaged reefs

A low-tech method for monitoring survival and growth of coral transplants at a boutique restoration site

Background Coral reef restoration projects are becoming a popular corporate environmental responsibility activity at hotel resorts. Such involvement of private businesses offers the potential to expand restoration into a new socioeconomic sector. However, the scarcity of user-friendly monitoring methods for hotel staff, but robust enough to detect changes over time, hinders the ability to quantify the success or failure of the restoration activity. Here, we present a monitoring method of easy application by hotel staff, without scientific training, using the standard resources available at a hotel resort. Methods Survival and growth of coral transplants were evaluated over 1 year at a boutique coral reef restoration site. The restoration was tailored to the needs of a hotel resort in Seychelles, Indian Ocean. A total of 2,015 nursery-grown corals of branching (four genera, 15 species), massive (16 genera, 23 species), and encrusting (seven genera, seven species) growth types were transplanted to a 1–3 m deep degraded patch reef. A unique cement mix was used to transplant corals onto the hard substrate. On the north side of each coral selected for monitoring, we attached an 8.2 cm × 8.2 cm reflective tile. We used reflective tiles instead of numbered tags due to the expected amount of biofouling growing on the tag surface. Every coral was recorded with top view photography (perpendicular to the plane of coral attachment), with the reflective square in the field of view. We drafted a map of the site to facilitate navigation and re-sighting of the monitored colonies. Then, we developed a simple monitoring protocol for hotel staff. Using the map, and the reflective tiles, the divers located the coral colonies, recorded status (alive, dead, bleaching), and took a photograph. We measured the two-dimensional coral planar area and the change in colony size over time using contour tissue measurements of photographs. Results The monitoring method was robust enough to detect the expected survival of coral transplants, with encrusting and massive corals outperforming branching corals. Survival of encrusting and massive corals was higher (50%–100%) than branching corals (16.6%–83.3%). The change in colony size was 10.1 cm2 ± 8.8 (SE). Branching coral survivors grew faster than massive/encrusting corals. A comprehensive approach to the boutique restoration monitoring experiment would have included comparisons with a control patch reef with a similar species composition to the coral transplants. However, the ability to monitor such a control site, in addition to the restoration site, was beyond the logistic capabilities of the hotel staff, and we were limited to monitoring survival and growth within the restoration site. We conclude that science-based boutique coral reef restoration, tailored to the needs of a hotel resort, combined with a simple monitoring method, can provide a framework for involving hotels as partners in coral reef restoration worldwide

Development of gene expression markers of acute heat-light stress in reef-building corals of the genus porites

Coral reefs are declining worldwide due to increased incidence of climate-induced coral bleaching, which will have widespread biodiversity and economic impacts. A simple method to measure the sub-bleaching level of heat-light stress experienced by corals would greatly inform reef management practices by making it possible to assess the distribution of bleaching risks among individual reef sites. Gene expression analysis based on quantitative PCR (qPCR) can be used as a diagnostic tool to determine coral condition in situ. We evaluated the expression of 13 candidate genes during heat-light stress in a common Caribbean coral Porites astreoides, and observed strong and consistent changes in gene expression in two independent experiments. Furthermore, we found that the apparent return to baseline expression levels during a recovery phase was rapid, despite visible signs of colony bleaching. We show that the response to acute heat-light stress in P. astreoides can be monitored by measuring the difference in expression of only two genes: Hsp16 and actin. We demonstrate that this assay discriminates between corals sampled from two field sites experiencing different temperatures. We also show that the assay is applicable to an Indo-Pacific congener, P. lobata, and therefore could potentially be used to diagnose acute heat-light stress on coral reefs worldwide.National Science Foundation grant DEB-1054766 to MVM; Title V-Graduate programs/ELITE Graduate program: Event Travel Request program to LBS and JAH; Environmental Protection Agency Greater Research Opportunity Graduate Fellowship to KAK (MA-91697601); WIOMSA MARG III to PHM and RB; Aharon Katzir-Katchalsky Student Travel Fellowships and Anat Krauskopf Fund Travel Award to AA; NSF IOS-0747205 and funding from the University of Mississippi ORSP to TLG; Grants from both the National Science Council and Academia Sinica, Taiwan to KS; NSF GRF to RNS; Natural Environmental Research Council (NERC) studentship to CVP. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript