Interview at National Public Radio

An interview about the historical marine megafauna in Florida and the goliath groupers.

On culling the endangered goliath grouper

Frias-Torres S. Conservation Biology [IN REVIEW]

Goliath grouper: A giant in our backyard.

Frias-Torres S. 2009.

Book Chapter; In: William L. Kruczynski & Pamela J. Fletcher (Eds). South Florida Marine Environments: An Ecological Synthesis. University of Florida. [In Review]

Range-wide status and conservation of the Goliath grouper

Theme Section Endangered Species Research, 2009

This THEME SECTION of ESR, which contains 12 papers,  focuses on the Range-wide status of the Goliath grouper. The goliath grouper Epinephelus itajara is one of the world’s largest and longest lived epinephalids. Heavily targeted by artisanal and recreational fisheries throughout its broad distributional range, the global declines in abundance and extirpation of goliath grouper spawning aggregations are of growing concern. Innovative research and management approaches coupled with international collaborative efforts are needed to address this pressing conservation problem.

This ESR THEME SECTION was catalyzed by a Symposium at the 60th Annual Conference of the Gulf and Caribbean Fisheries Institute (GCFI)  In preparation for the Symposium, I compiled an electronic library of all publications available to date on Goliath grouper, including peer-review papers, reports, thesis, and other gray literature. Such electronic library is known as the "Goliath Grouper Book of Knowledge" and was distributed among the participants of the GCFI Symposium.

Using dual-frequency sonar to detect juvenile goliath grouper Epinephelus itajara in mangrove habitat

Frias-Torres S, Luo J. 2009. Endangered Species Research 7: 237–242.    FREE OPEN SOURCE DOWNLOAD

We tested alternative methods to diver visual censuses of juvenile goliath grouper  Epinephelus itajara in turbid mangrove habitat. We used a dual-frequency identification sonar (DIDSON) acoustic camera. DIDSON generates high resolution images of fish with a high-frequency multibeam sonar. The system can record the shape, size and movement of fish under low visibility conditions. A paired DIDSON–digital underwater video camera system was used to survey the mangrove shorelines of Niles Channel, in the Lower Florida Keys, USA. In high visibility conditions, the specific E. itajara DIDSON acoustic signal was obtained and used to evaluate DIDSON’s performance for E. itajara surveys in turbid conditions. Under both clear and turbid conditions DIDSON enabled the quantification and measurement of juvenile E. itajara in mangrove undercuts and submerged
dead trees that were not visible or detected using video or by a diver. DIDSON could not detect immobile juveniles, as it was unable to discern them from the substrate or the underwater structures where they rested. We demonstrate that mangrove microhabitat underwater structures do not interfere with acoustic fish signals. This study represents the first known successful application of a DIDSON acoustic camera in mangrove shorelines to achieve juvenile E. itajara detection and sizing.

Evaluation of finrays as a non-lethal ageing method for protected goliath grouper Epinephelus itajara

Murie DJ, Parkyn DC, Koenig CC, Coleman FC, Schull J, Frias-Torres S. 2009. Endangered Species Research 7: 213–220.      FREE OPEN SOURCE DOWNLOAD

Currently, there is a conflict between the need to conserve protected fish species and the need to use lethal methods to collect essential biological data, such as age, to assess their population status and recovery trends. We evaluated the precision and accuracy of a non-lethal ageing method for goliath grouper Epinephelus itajara, listed as critically endangered on the IUCN Red List of Threatened Species. Paired finray and otolith samples (n = 21) were collected opportunistically from fish that had died primarily from red tide or hypothermal events in Florida coastal waters. Finray ageing proved relatively precise (coefficient of variation [CV] = 4.24%), although less so than otolith ageing (CV = 1.45%). Finray ages agreed with otolith ages the majority of the time (CV = 3.15% and concordance correlation coefficient = 0.991) for E. itajarafrom 0 to 18 yr of age. Based on a test of symmetry, finray ageing was also relatively unbiased for fish up to 18 yr of age. Further evaluation of any limitations of the method will depend on obtaining more samples, especially from larger, presumably older, fish. Clearly, the non-lethal finray ageing method can be used as an alternative to using otoliths for goliath grouper at least up to 18 yr of age. Finray ageing could significantly reduce the need to sacrifice protected E. itajarato assess their population recovery.

Activity patterns of three juvenile goliath grouper, Epinephelus itajara, in a mangrove nursery

Frias-Torres et al. 2007, Bulletin of Marine Science 80(3): 587–594

The goliath grouper (jewfish) , Epinephelus itajara, is found in tropical and subtropical waters of eastern and western Altantic ocean.  The species—listed as critically endangered by the World Conservation Union has been protected through a total fishing ban in U.S. federal and state waters since 1990  and in puerto Rico and U.S. virgin Islands waters since  2004. As one of the few grouper species that shows a high affinity for mangrove-dominated areas, E. itajara typically spends its first 5–8 yrs in that nearshore habitat before migrating to adult habitats (i.e., coral reefs, rock ledges, isolated patch reefs, and artificial structures) . To date, knowledge of the movement of goliath grouper juveniles within their mangrove
nursery areas is based mainly on conventional tagging studies, which provide  limited insight into the fine-scale activity patterns. In the present study, we used electronic acoustic tags and stationary hydrophone receiver stations to examine the activity patterns of three tagged juveniles inhabiting the fringing red mangrove shorelines of Ten Thousand Islands, southwest Florida, U.S.A.  Our primary objective was to examine the extent to which juvenile activity was associated with time of day and tidal stage. To test our ability to detect movement at fine timescales over periods of weeks to months, as well as cues for fish movement, we examined the relationship between fish presence- absence, tidal cycle, and time of day in juvenile goliath grouper. Our results provide insight into multiple habitat use by this species and are important to consider when designing and implementing population abundance surveys.

Habitat use of juvenile goliath grouper Epinephelus itajara in the Florida Keys, USA

Frias-Torres s. 2006. Endangered Species Research 2: 1-6    FREE OPEN SOURCE DOWNLOAD

This study reports the distribution, abundance and habitat use of juvenile goliath grouper Epinephelus itajaraalong fringing red mangrove Rhizophora mangleshorelines of the Florida Keys, USA. The species has been protected from fishing in US waters since 1992, after reaching commercial extinction, yet juvenile habitat use remains poorly studied. The aim of this study was 
to evaluate the importance of underwater mangrove habitat structure and complexity in determining distribution of juvenile goliath grouper in the Florida Keys. Visual underwater surveys were used to record juvenile presence, abundanceand size. Habitat characteristics as continuous variables (depth, canopy, overhang and prop root width) and nominal variables (bottom type, sun exposure, shoreline shape and shoreline type) were also recorded. Juveniles aggregated in sites with high structural complexity, soft sediment and eroded shorelines. Well developed fringing red mangrove shorelines were the preferred juvenile goliath grouper habitat.

[Fifty percent of coral reefs are close to collapse] El 50 % de los arrecifes de coral estan al borde del colapso

Frias-Torres S. 2007. El Periódico, Barcelona, Spain, published in Spanish, July 16, 2007

Download full article here at Academia.edu

Large Pelagic Fish Distribution in the Tropical Western Atlantic Relevant to Conservation

Frias-Torres, S. 2005. Proceedings Gulf and Caribbean Fisheries Institute 56, 253-258

Migratory habits of large pelagic fish often limit conservation efforts.Identification of sensitive sites (feeding aggregations and spawning areas), is essential for effective conservation strategies. The location of whale shark sightings and spawning areas for bluefin tuna, swordfish and blue marlin in the tropical western Atlantic obtained from the literature or from unpublished data were used to create a geographic information system (GIS). The location of existing marine protected areas and high priority conservation areas was also added to the GIS. Results show that whale shark sightings and spawning sites for bluefin tuna, swordfish and blue marlin in the tropical western Atlantic are very specific. This information may help in understanding the biology of the species essential in future conservation strategies.

Whale sharks and marine protected areas in the tropical western Atlantic

Frias-Torres S. 2004. Current: the Journal of Marine Education 20 (3): 39-40.

Most large pelagic fish have a migratory life history. Such nomadic lifestyle makes conservation efforts challenging, in part because international collaboration is needed to protect these species.

Notes on aquarium brood release and feeding of the opossum pipefish, Microphis brachyurus lineatus

Frias-Torres S. 2004. Gulf and Caribbean Research, 16: 73-75

Short Communication. Download article at Academia.edu

Oceanic transport and life history of the tropical western Atlantic oppossum pipefish, Microphis brachyurus lineatus