Status Review Report of Two Species of Guitarfish: Rhinobatos rhinobatos and Rhinobatos cemiculus Rhinobatos cemiculus caught in Mayumba Gabon, Credit: Godefroy De Bruyne, Wildlife Conservation Society Brendan Newell 2017 National Marine Fisheries Service National Oceanic and Atmospheric Administration Silver Spring, MD i Acknowledgements I would like to thank Ms. Sofia de Benedictis, Mr. Godefroy De Bruyne, Dr. Fabrizio Serena, Dr. Dr. Nuri Basusta, and Dr. Youssouph Diatta for providing information and data that assisted in the development of this report, Dr. Beth Polidoro and Dr. Thomas Munroe for their help connecting us with marine resource professionals in Africa, and Ms. Angela Somma, Ms. Marta Nammack, and Ms. Maggie Miller for their review of this document. Additionally, I would like to thank peer reviewers Dr. Christian Capapé, Dr. Francis Nunoo, and Dr. Ayman Mabrouk for the information and data they provided as well as their time and professional review of this report. This document should be cited as: Newell, B.M. (2017) Status Review Report of Two Species of Guitarfish: Rhinobatos rhinobatos and Rhinobatos cemiculus. Report to National Marine Fisheries Service, Office of Protected Resources. 62 pp. ii Executive Summary This report was produced in response to a petition received from WildEarth Guardians on July 15, 2013, to list 81 marine species as endangered or threatened under the Endangered Species Act (ESA). On February 24, 2014, NMFS announced in the Federal Register that the petition presented substantial information that listing may be warranted for five of the petitioned species of skates and rays and requested information on these species from the public (79 FR 10104). This report is the status review for two of the five species of skates and rays, namely, Rhinobatos cemiculus and Rhinobatos rhinobatos. On September 19, 2016, NMFS published in the Federal Register a proposed rule to list R. rhinobatos and R. cemiculus as threatened species under the ESA (81 FR 64094). At that time, we solicited comments on the proposed rule and draft status review report. This final report summarizes available data and information on these two guitarfish species, including information we received during the 60-day public comment period, and presents an evaluation of their status and extinction risk. Rhinobatos rhinobatos, commonly referred to as the common guitarfish, historically occurred throughout all shores of the Mediterranean and along the coast of the eastern Atlantic from southern France to Angola, in shallow waters to 100m depth. The available information shows declines in this species throughout much of its range including extirpation from the Mediterranean waters of Spain, France, Italy, and likely the entire Adriatic Sea. In the Atlantic this species was abundant in West Africa prior to the beginning of targeted shark fishing in the region, but has become scarce in recent decades. Rhinobatos cemiculus, commonly referred to as the blackchin guitarfish, historically occurred throughout most shores of the Mediterranean, with the likely exception of the coast of France, eastern Atlantic from southern Portugal to Angola, in shallow waters to 100m depth. The available information shows declines in this species throughout much of its range including extirpation from the Mediterranean waters of Spain, Italy, and likely the entire Adriatic Sea. In the Atlantic this species was abundant in West Africa prior to the beginning of targeted shark fishing in the region, but has become scarce in recent decades. The decline of these Rhinobatos species is primarily attributed to the historical and current overutilization of these species by demersal fisheries. Throughout portions of their range they are targeted for their meat, fins, or both, and throughout their entire ranges they are susceptible to capture by various fishing gears used by demersal artisanal and industrial fisheries. As with many elasmobranch species, both species have a relatively low reproductive capacity, leaving them vulnerable to overutilization by fisheries. While there have been recent regulatory efforts to reduce the pressure of fishing on these and other elasmobranch species in portions of their ranges, many of these protections are either inadequate, or their efficacy is unknown at this time. Given the species’ demographic risks and the present threats that continue to contribute to the decline of many of the existing populations, we conclude that R. rhinobatos and R. cemiculus are presently at a moderate risk of extinction throughout their respective ranges. iii Contents Introduction .................................................................................................................................................. 1 Scope and Intent of Present Document .................................................................................................... 1 Life History and Ecology ................................................................................................................................ 1 Taxonomy and Distinctive Characteristics ................................................................................................ 1 Historical Range and Habitat Use ............................................................................................................. 2 Feeding and Diet ....................................................................................................................................... 4 Reproduction and Growth ........................................................................................................................ 5 Distribution and Historical or Current Abundance ..................................................................................... 16 Mediterranean ........................................................................................................................................ 16 Rhinobatos rhinobatos ........................................................................................................................ 20 Rhinobatos cemiculus ......................................................................................................................... 22 Atlantic .................................................................................................................................................... 23 Analysis of the ESA Section 4(A)(1) Factors ................................................................................................ 27 Present or Threatened Destruction, Modification, of Curtailment of Habitat or Range ........................ 27 Curtailment of Range .......................................................................................................................... 27 Destruction or Modification of Habitat .............................................................................................. 28 Overutilization for Commercial, Recreational, Scientific, or Educational Purposes ............................... 29 Commercial Overutilization in the Mediterranean ............................................................................. 30 Commercial Overutilization in the Atlantic ......................................................................................... 36 Disease or Predation ............................................................................................................................... 40 Inadequacy of Existing Regulatory Mechanisms..................................................................................... 40 Regulatory Mechanisms in the Mediterranean .................................................................................. 40 Regulatory Mechanisms in the Eastern Atlantic ................................................................................. 41 Other Natural or Manmade Factors ....................................................................................................... 43 Climate Change ................................................................................................................................... 43 Invasion by Alien Species .................................................................................................................... 44 Extinction Risk Analysis ............................................................................................................................... 45 Rhinobatos rhinobatos ............................................................................................................................ 46 Demographic Risk Analysis ................................................................................................................. 46 Threats Assessment ............................................................................................................................ 48 Risk of extinction ................................................................................................................................. 48 iv Rhinobatos cemiculus ............................................................................................................................. 49 Demographic Risk Analysis ................................................................................................................. 49 Threats Assessment ............................................................................................................................ 51 Risk of extinction ................................................................................................................................