Important juvenile manta ray habitat at Flower Garden Banks National Marine Sanctuary in the northwestern Gulf of Mexico
Oceanic manta rays (Mobula birostris) are large pelagic planktivores that are threatened globally by targeted fisheries and bycatch. While studies of oceanic mantas have increased substantially in the past decade, major knowledge gaps remain in their basic biology, ecology and life history. The juvenile stage in particular is virtually unstudied, as juvenile oceanic mantas are rarely observed in the wild and are known primarily from fisheries and captive individuals. Here, we present evidence suggesting that Flower Garden Banks National Marine Sanctuary (FGBNMS) is an important habitat for juvenile manta rays. Recent genetic evidence indicates that both oceanic mantas and a proposed third manta species (Mobula cf. birostris) are present at FGBNMS. Size estimates of mantas sighted at FGBNMS over 25 years of monitoring efforts indicate that 95% of individuals are smaller than the size at maturity for male M. birostris, and 80% are smaller than the size at maturity for M. alfredi. Photographic records of juvenile males with undeveloped claspers further corroborate these findings. Temporal patterns of use and the prevalence of juveniles suggest that this region may serve as nursery habitat for M. birostris and M. cf. birostris. Further research is necessary to determine the importance of the region to juveniles of each species, as well as long-term patterns of habitat use and residency.
The data presented here were collected during NOAA cruises to the Flower Garden Banks National Marine Sanctuary. These cruises were funded jointly by NOAA ONMS, the Bureau of Ocean Energy Management, National Marine Sanctuary Foundation, and the Bureau of Safety and Environmental Enforcement. We thank all the FGBNMS and recreational SCUBA divers who provided their sighting data and Anna Knochel for updating the sightings database. Long-term monitoring data collection from 2010 to 2017 was funded through an interagency agreement between the Bureau of Ocean Energy Management and the National Oceanic and Atmospheric Administration’s National Ocean Service, Office of National Marine Sanctuaries, through Flower Garden Banks National Marine Sanctuary. We thank three anonymous reviewers for their comments on a previous version of this manuscript.
JDS was supported by NOAA ONMS Nancy Foster Scholarship NA15NOS4290068.
Compliance with ethical standards
Conflict of interest
All authors declare no conflicts of interest.
All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.
- Bohnsack JA, Bannerot SP (1986) A stationary visual technique for quantitatively assessing community structure of coral reef fishes. NOAA Tech Rep NMFS 41:1–15Google Scholar
- Braun CD, Skomal GB, Thorrold SR, Berumen ML (2015) Movements of the reef manta ray (Manta alfredi) in the Red Sea using satellite and acoustic telemetry. Marine Biology. Springer, BerlinGoogle Scholar
- Johnston MA, Nuttall MF, Eckert RJ, Embesi JA, Slowey NC, Hickerson EL, Schmahl GP (2013) Long-term monitoring at the East and West flower Garden Banks National Marine Sanctuary, 2009–2010, volume 1: technical report. U.S. Dept. of Interior, Bureau of Ocean Energy Management, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study BOEM 2013-215, p 362Google Scholar
- Johnston MA, Nuttall MF, Eckert RJ, Embesi JA, Slowey NC, Hickerson EL, Schmahl GP (2015) Long-term monitoring at the East and West Flower Garden Banks National Marine Sanctuary, 2011–2012, volume 1: technical report. U.S. Dept. of Interior, Bureau of Ocean Energy Management, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study BOEM 2015-027, p 194Google Scholar
- Johnston MA, Eckert RJ, Nuttall MF, Sterne TK, Embesi JA, Manzello DP, Hickerson EL, Schmahl GP (2017a) Long-term monitoring at the East and West Flower Garden Banks National Marine Sanctuary, 2013–2015, volume 1: technical report. U.S. Dept. of Interior, Bureau of Ocean Energy Management, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study BOEM 2017-058, p 186Google Scholar
- Johnston MA, Sterne TK, Eckert RJ, Nuttall MF, Embesi JA, Walker R, Hu X, Hickerson EL, Schmahl GP (2017b) Long-term monitoring at East and West Flower Garden Banks, 2016 Annual Report. Marine Sanctuaries Conservation Series ONMS-17-09. U.S. Department of Commerce, National Oceanic and Atmospheric Administration, Flower Garden Banks National Marine Sanctuary, Galveston, TX, p 132Google Scholar
- Kaltenberg AM, Biggs DC, DiMarco SF (2007) Deep scattering layers of the Northern Gulf of Mexico observed with a shipboard 38-kHz acoustic doppler current profiler. Gulf Mex Sci 2:97–108Google Scholar
- Lewis SA, Nanen S, Dharmadi F, O’Malley MP, Campbell SJ, Yusuf M, Sianipar A (2015) Assessing Indonesian manta and devil ray populations through historical landings and fishing community interviews. PeerJ PrePints:1–20Google Scholar
- Marshall AD, Compagno LJV, Bennett MB (2009) Redescription of the genus Manta with resurrection of Manta alfredi. Zootaxa 28:1–28Google Scholar
- Marshall AD, Bennett MB, Kodja G, Hinojosa-Alvarez S, Galvan-Magana F, Harding M, Stevens G, Kashiwagi T (2011) Manta birostris. http://www.iucnredlist.org/details/198921/0. Accessed 1 Jan 2018
- Notarbartolo-Di-Sciara G (1988) Natural history of the rays of the genus Mobula in the Gulf of California. Fish Bull 86:45–66Google Scholar
- O’Malley MP, Townsend KA, Hilton P, Heinrichs S, Stewart JD (2016) Characterization of the trade in Manta and devil ray gill plates in China and Southeast Asia through trader surveys. Aquat Conserv Mar Freshw Ecosyst 27:1–41Google Scholar
- Stevens GMW (2016) Conservation and population ecology of Manta rays in the Maldives. University of York, YorkGoogle Scholar
- Stewart JD, Rohner CA, Araujo G, Avila J, Fernando D, Forsberg K, Ponzo A, Rambahiniarison JM, Kurle CM, Semmens BX (2017) Trophic overlap in mobulid rays: insights from stable isotope analysis 580:131–151Google Scholar
- Zimmer BL, Duncan L, Aronson RB, Deslarzes KJP, Deis D, Robbart ML, Precht WF, Kaufman L, Shank B, Weil E, Field J, Evans DJ, Whaylen L (2010) Long-term monitoring at the East and West Flower Garden Banks, 2004–2008. Volume I: technical report. US Department of the Interior, Bureau of Ocean Energy Management, Regulation, and Enforcement, Gulf of Mexico OCS region, New Orleans. OCS Study BOEMRE 2010-052, p 310Google Scholar