Ecology of Manta Rays Kelly Newton, Don Croll, Kevin Weng, Felipe Galvan, John O Sullivan Sullivan, Ellen Freund, Heidi Dewar Alejandro Acevedo, Bernie Tershy
Trophically Simple Top Predators
Linked to oceanography
Fin whales in the Gulf of California
Fin whale tagging & tracking -Time-depth recorders Dive profile description -Echosounders Vertical density of krill Loreto La Paz
Depth (m) Fin Whales Krill Schools Day Night Day Night 0 0 10 10 20 20 30 30 40 40 50 50 60 60 70 70 80 80 90 90 100 100 150 150 200 200 250 250 300 300 350 350 400 400 450 450 500 500-40 -20 0 20 40-80 -60-40 -20 0 20 40 60 80 Depth (m) Frequency Foraging Dives Frequency Krill Aggregations
Isla El Pardito
Small Scale Artisanal Fisheries Gulf of California i
Small Scale Artisanal Fisheries Gulf of California Il Isla San Jose El Pardito Isla San Francisquito
Spine-tail Devil Ray Mobula japanica Near Threatened (IUCN 2006) Large size (3m Disk Width) Large size @ maturity (2m DW) Low Fecundity Highly Migratory
x El Pardito
Depth (m) Manta Rays Day Night 10 20 30 40 50 60 70 80 90 100 150 200 250 300 350 400 450 500 50 40 30 20 10 0 1020304050 Percent Time (%) Depth (m) 0 10 20 30 40 50 60 70 80 90 100 150 200 250 300 350 400 450 500 Krill Schools Day Night -40-20 0 20 40 Percent of Krill Schools
Spine-tail Devil Ray Mobula japanica Last & Stevens 1994
Monterey Bay Aquarium Husbandry Group Habitat t preferences Movement patterns link to oceanography Fisheries i issues & conservation implications
Rodeo Technique
2004 2007 Pop-up Archival Tags 10 Males 3 Females Mean Disc Length: 93 cm Tag Deployments: 1076 days totalt 83 52 days (mean SD) Max: 188 days
Habitat Preferences Time at Depth Time at Temperature <0 >30 0-5 27.5-30 5-20 25-27.5 Depth (m m) 20-50 50-100 100-150 150-200 200-300 re (C) Temperatu 22.5-25 20-22.5 17.5-20 15-17.5 12.5-15 300-400 10-12.512 400-500 7.5-10 500-750 5-7.5 >750 <5-0.5 0 0.5 Proportion of time Waters shallower than 50m -0.5 0 0.5 Proportion of time Temperature 22.5 27.5ºC
Movement Patterns June July August September
June July August September 14 16 18 20 22 24 26 28 30 32
-3 Averag e Euphausia acea indiv m 70 60 50 40 30 20 10 0 Krill Abundance Feb April July Oct IMECOCAL Cruise Data 2004 Lines 123-140 From Lavaniegos et al. 2006
Loggerhead Sea Turtles Peckham et al 2007 Manta Rays Blue Whales Etnoyer et al 2006 Yellowfin Tuna Schaefer et al 2007
June July August September Schaefer et al. 2007
Yellowfin Tuna Purse Seine Fishery F/V Hanna: Mexico
200000 Total YFT 180000 200000 Total YFT 160000 180000 160000 180000 120000 140000 120000 140000 80000 100000 80000 100000 Metric tons 40000 60000 40000 60000 M 0 20000 20000 40000 0 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 0 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 IATTC 2008
2008 Yellowfin Tuna Purse Seine Distributions IATTC 7-10
2008 Purse Seine Fishery 186,000 mt Yellowfin Tuna 45.5% in Mexico Bycatch: Rays (Mobulidae & Dasyatidae) - 48 mt (33 NOA sets) ~ 500 animals
Conservation Implications Vulnerable to small artisanal fisheries & large purse seine tuna fishery Prohibited to catch: November 2005
Mobula japanica Last & Stevens 1994
Mobula japanica Last & Stevens 1994
Conservation Implications Worldwide Purse Seine Fisheries Western Indian Ocean: 425 per year Also fisheries in Indonesia, New Zealand, India, Sri Lanka, & Thailand Reduce bycatch of Manta Rays Need to know movement patterns, fisheries i mortality, population structure, and population biology
Population Genetics Mobula japanica Questions that cannot be resolved Mobula munkiana using tagging data: Stock structure Implications of migration Integration of long-term trends
Population Genetics Research Questions 1. What are the relationships within the family Mobulidae?
Manta Rays?
Population Genetics Research Questions 1. What are the relationships within the family Mobulidae? 2. Spatial scale and connectivity of genetically defined populations (aka genetic stocks) of manta rays in the tropical Pacific?
Approach: Sampling Sea of Cortez 11 7 3 12 4 5 2 6 9 8 10
Family Mobulidae Mobula japanica M. munkiana M. thurstoni M. tarapacana Manta birostris M. mobular M. eregoodootenkee M. hypostoma M. rochebrunei M. kuhlii
Family Mobulidae Baja California Mobulids Mobula japanica M. munkiana M. thurstoni M. tarapacana Manta birostris M. mobular M. eregoodootenkee M. hypostoma M. rochebrunei M. kuhlii
Mobula munkiana Near Threatened (IUCN 2006) Small size (110cm Disk Width) Smaller size @ maturity (97 cm DW) Form large schools Low Fecundity Migratory (?)
Mobula munkiana Last & Stevens 1994
2007 2010 Mobula munkiana
Mobula munkiana 2007: 2 1 male: 29 days 1 female: 66 days 2008: 6 2 males 4 females 17 75 days ~400 tracking days 2009: NONE 2010: 3 awaiting results!
japanica vs. munkiana Solitary Diet: Krill Pelagic Shallow > 50 m Majority left GOC Schools Diet: Krill & Mysids Coastal Shallow > 50 m All stayed within GOC
= pop up location Isla El Pardito
2009 Field Season Mobula thurstoni Near Threatened (IUCN 2006) Medium size (180cm Disk Width) Short head & cephalic lobes Form small schools Low Fecundity Migratory (?)
Mobula thurstoni Last & Stevens 1994
2009 Field Season Mobula thurstoni 4 PAT Tags - 3 Males -1 Female
= pop up location Isla El Pardito
2010 Field Season Mobula thurstoni 7 PAT & MiniPAT Tags -1 Male -6 Females -Pregnant
= pop up location Isla El Pardito
Family Mobulidae Baja California Mobulids Mobula japanica M. munkiana M. thurstoni M. tarapacana Manta birostris M. mobular M. eregoodootenkee M. hypostoma M. rochebrunei M. kuhlii
Family Mobulidae IUCN Red List Mobula japanica M. munkiana M. thurstoni M. tarapacana Manta birostris M. mobular M. eregoodootenkee M. hypostoma M. rochebrunei M. kuhlii
Manta Ray Research References: Elasmobranch 4,872 Mobulidae - 46 ISI Web of Knowledge
2006 Collaboration with Monterey Bay Aquarium Husbandry Group
Moby May 13, 2006 December 29, 2007
Future Work... Potential captures in Pacific to decrease transport time Assist with work in Bahia de Los Angeles Mobula japanica movements publication Comparison publication Continue genetics research
Acknowledgements Cuevas Family, Isla El Pardito Monterey Bay Aquarium National Geographic Society Field crew: CICIMAR students, family, friends Dana Wingfield & Dave Foley (SST satellite images)