The distribution of manta rays in the western North Atlantic Ocean off the eastern United States

Abstract

In 2018, the giant manta ray was listed as threatened under the U.S. Endangered Species Act. We integrated decades of sightings and survey effort data from multiple sources in a comprehensive species distribution modeling (SDM) framework to evaluate the distribution of giant manta rays off the eastern United States, including the Gulf of Mexico. Manta rays were most commonly detected at productive nearshore and shelf-edge upwelling zones at surface thermal frontal boundaries within a temperature range of approximately 20–30 °C. SDMs predicted highest nearshore occurrence off northeastern Florida during April, with the distribution extending northward along the shelf-edge as temperatures warm, leading to higher occurrences north of Cape Hatteras, North Carolina from June to October, and then south of Savannah, Georgia from November to March as temperatures cool. In the Gulf of Mexico, the highest nearshore occurrence was predicted around the Mississippi River delta from April to June and again from October to November. SDM predictions will allow resource managers to more effectively protect manta rays from fisheries bycatch, boat strikes, oil and gas activities, contaminants and pollutants, and other threats.

Modeling protected species distributions and habitats to inform siting and management of pioneering ocean industries: A case study for Gulf of Mexico aquaculture

“…Standardized aerial surveys were subject to both perception and availability bias that may be especially problematic for small, cryptic, or diving animals such as sea turtles and manta rays. The SDM for manta rays accounted for these biases and underlying aerial survey effort [42]. Similar efforts to develop predictive models using aerial, ship, and PAM survey data are underway for most protected species.…”

“…Giant manta ray. Using distance-weighting methods to account for individual survey effort, [42] fit a species distribution model (SDMs) to a combined dataset of giant manta ray (Manta birostris) sightings generated from 1) Southeast Fisheries Science Center (SEFSC), 2) North Atlantic Right Whale Consortium (NARWC), and 3) New York State Energy Research and Development (NYSERDA) aerial surveys. The best-fitting model with the highest predictive power estimated peak probability of occurrence in areas with warm sea surface temperatures (SST), moderate Z-transformed SST frontal gradients (Front-Z), nearshore and shelfedge depths, moderate bathymetric slopes, and increasing Chl-a concentrations [42].…”

“…Because aquaculture development and associated impacts to protected species may occur on time scales of many months to years, we wanted to capture the distribution of giant manta rays across a broad suite of environmental conditions. To that end, the final [42] combined survey SDM was fit to gridded monthly environmental data from January 2003 to December 2019. Environmental parameters from the following sources were fit to a 10×10 km GIS grid in R by month and year.…”

Manta and devil ray species occurrence and distribution in Venezuela, assessed through fishery landings and citizen science data

“…birostris were most abundant around the coral atoll systems of Los Roques Archipelago. The site preferences noted here match with what is known about habitat use for these species elsewhere throughout their range (Kashiwagi et al ., 2012, Hacohen‐Domené et al ., 2017, Stevens et al ., 2018, Lezama‐Ochoa et al ., 2020; Garzón et al ., 2021, Farmer et al ., 2022).…”

“…Despite the potential for manta ray-related eco-tourism activities to provide sustainable economic benefits to the area, the Venezuelan political and economic situation has hindered the growth of tourism in recent decades (Gutiérrez & Narváez, 2015). Consequently, citizen science data availability for mobulids and other megafauna in these species elsewhere throughout their range (Kashiwagi et al, 2012, Hacohen-Domené et al, 2017, Lezama-Ochoa et al, 2020Garz on et al, 2021, Farmer et al, 2022.…”