Greenback Parrotfish (Scarus trispinosus) Status Review Report M.O. Freitas 2007 from FishBase• February 2015 Ronald J. Salz Fishery Biologist National Marine Fisheries Service National Oceanic and Atmospheric Administration Silver Spring, MD Acknowledgements I thank the following people who provided information and feedback that greatly assisted in preparing this report: Marta Nammack, Angela Somma, Therese Conant, Maggie Miller, Lisa Manning, Dwayne Meadows, Kerry Whitaker, Jennifer Schultz, Renata Pereira, Mia Theresa Comeros, Beatrice Ferreira, and Guilherme Dutra. I also thank Howard Choat and Robert Warner for providing their time, expertise, and insights as external peer reviewers of the draft report. This document should be cited as: Salz, R. J. 2015. Greenback Parrotfish (Scarus trispinosus) Status Review Report. Report to National Marine Fisheries Service, Office of Protected Resources. February 2015, 56 pp. 2 Executive Summary On July 15, 2013, NMFS received a petition to list 81 species of marine organisms as endangered or threatened species under the Endangered Species Act (ESA). If an ESA petition is found to present substantial scientific or commercial information that the petitioned action may be warranted, a status review shall be promptly commenced (16 U.S.C. 1533(b)(3)(A)). NMFS determined that for 27 of the 81 species, including the greenback parrotfish, the petition had sufficient merit for consideration and that a status review was warranted (79 FR 10104, February 24, 2014). This document is the ESA status review report for the greenback parrotfish, Scarus trispinosus. Greenback parrotfish are endemic to Brazil and range from Manuel Luiz Reefs off the northern Brazilian coast to Santa Catarina on the southeastern Brazilian coast. A major part of their range is the Abrolhos reef complex, encompassing an area of approximately 6,000 km2 on the inner and middle continental shelf of the Abrolhos Bank. Greenback parrotfish are habitat “generalists” and have been recorded dwelling in coral reefs, algal reefs, seagrass beds and rocky reefs, at depths ranging from 1 m to at least 30 m. The greenback parrotfish is one of the largest parrotfish species with maximum sizes reported around 90 cm. Species in the genus Scarus typically exhibit the following reproductive characteristics: protogynous (female first) hermaphroditism, breeding territories, harems, and external fertilization. Large “terminal phase” male parrotfish establish feeding territories which both attract females and are grazed continuously over a period of time. Greenback parrotfish are classified as detritivores (or sometimes roving herbivores) and only occasionally graze on live coral. The following demographic risk factors were considered in the extinction risk analysis: abundance; growth rate/productivity; spatial structure/connectivity; and diversity. These demographic risk factors reflect concepts that are well founded in conservation biology and that individually and collectively provide strong indicators of extinction risk. According to Section 4 of the ESA, the Secretary (of Commerce or the Interior) determines whether a species is threatened or endangered as a result of any (or a combination) of the following factors: (A) destruction or modification of habitat, (B) overutilization, (C) disease or predation, (D) inadequacy of existing regulatory mechanisms, or (E) other natural or man-made factors. Specific threats to the greenback parrotfish from each of these five factors were considered. Due to the lack of information regarding threats and the species’ life history and ecology, significant uncertainties exist surrounding the levels of risk posed by these threats and demographic factors. Because information on the greenback parrotfish is sparse and often non-quantitative, qualitative risk categories were used to characterize the threats and demographic risk factors. Scientific conclusions about the overall risk of extinction were based on the likelihood and contribution of each particular factor, synergies among contributing factors, and the cumulative impact of all demographic risks and threats on the species. The relatively long life span of this species (estimated at 23 years) means threats can have long-lasting impacts. I defined foreseeable future for the greenback parrotfish extinction risk analysis as approximately 40 years. The likelihood that each particular demographic factor and threat contributes significantly to the greenback parrotfish extinction risk is presented in the table below. The term “significantly” is 3 used here as it is generally defined – i.e., in a sufficiently great or important way as to be worthy of attention. Ratings are based on a five item scale: Very low = very unlikely; Low = unlikely; Moderate = somewhat likely; High = likely; and Very high = very likely. Extinction Risk Factor Likelihood that particular factor contributes significantly to the greenback parrotfish risk of extinction Demographic Factor Abundance Low Growth rate/productivity Low Spatial structure/connectivity Very low Diversity Very low ESA Section 4(a)(1) Threat Present or threatened destruction, modification, Low or curtailment of habitat or range Overutilization by artisanal and commercial Moderate fisheries Competition, disease, or predation Very low Other natural or man-made factors Very low Evaluation of adequacy of existing regulatory Moderate mechanisms A recent quantitative assessment of the greenback parrotfish fishery on Abrolhos Bank indicates a very high level of exploitation of this species. The lack of a catch record time series or baseline information prevented a traditional assessment of the status of this species that would ideally be available for an extinction risk analysis. Instead, a Productivity and Susceptibility Analysis (PSA), designed for data deficient and small scale fisheries, placed the greenback parrotfish in the zone of high potential risk of overfishing. Despite study limitations, other research suggests that fishing pressure has reduced the abundance of greenback parrotfish, and in some localities the reduction has been significant. Due to uncertainties and limitations associated with the available data, it is difficult to quantitatively assess the magnitude of the decline in abundance caused by fishing, or to project the magnitude of future impacts of fishing on greenback parrotfish abundance or species survival. With regard to the threat of overutilization by artisanal and commercial fisheries I conclude that this factor is somewhat likely to contribute significantly to the greenback parrotfish extinction risk both now and in the foreseeable future. Traditional fishing regulations designed to limit catch and effort of reef fishes are either non-existent or poorly enforced throughout most of the greenback parrotfish range. Systemic problems associated with the enforcement of no-take marine reserves also contribute to the inadequacy of existing regulatory mechanisms to address the threat to greenback parrotfish from fishing. I conclude that the inadequacy of existing regulatory mechanisms is somewhat likely to contribute significantly to the greenback parrotfish extinction risk both now and in the foreseeable future. Although scientific studies indicate that some portion of habitat used by greenback parrotfish has been degraded, the available information does not support a conclusion that habitat associated 4 changes contribute to the extinction risk of this species in a significant way. Therefore, I conclude that it is unlikely that the threat of “destruction, modification, or curtailment of habitat or range” contributes significantly to greenback parrotfish extinction risk either now or in the foreseeable future. Based on the sparse information pertaining to the threats “competition, disease, or predation” and “other natural or man-made factors”, I conclude that it is highly unlikely that these threats contribute significantly to greenback parrotfish extinction risk either now or in the foreseeable future. All of the demographic factors evaluated were categorized as either unlikely or very unlikely to contribute significantly to the current extinction risk. Although available information on this species is limited, there are no indications that this species is currently at risk of extinction based on demographic viability criteria. Information on relative abundance and mean density from UVC surveys suggest that greenback parrotfish are still a commonly occurring species on many Brazilian reefs and represent a relatively large proportion of the total fish biomass on some reefs. After considering the cumulative evidence from all the information available, I conclude that the greenback parrotfish currently faces a low risk of extinction throughout its range. This determination is based, in part, on the conclusion that demographic factors related to abundance and productivity are not likely to contribute to the current extinction risk. However, considering the future threat of overutilization from artisanal and commercial fishing and the inadequacy of existing regulatory mechanisms, it is likely that abundance of this species will decrease in the future. As a protogynous hermaphroditic species, greenback parrotfish may be more susceptible to fishing methods that selectively target the largest individuals in the population. Continued selective removal of terminal males, individuals undergoing sexual transition, and the largest females at high rates will result in decreased productivity and likely increase