311 — Important juvenile manta ray habitat at Flower Garden Banks National Marine Sanctuary in the northwestern Gulf of Mexico

Stewart et al (10.1007/s00227-018-3364-5)

Read on 27 June 2018
#marine-biology  #manta-ray  #ocean  #pelagic  #Gulf-of-Mexico  #development  #biology 

Not much is known about juvenile oceanic manta rays because the species is both rare as well as largely pelagic, and so it’s much easier in comparison to study their coastal reef relatives.

I had to read this sentence a few times before it stuck: Oceanic rays can reach up to 7 meters in disk width. That’s bonkers! These marine biologists looked at a site in the northwest of the Gulf of Mexico: At the Flower Garden Banks National Marine Sanctuary (FGBNMS), oceanic rays are seen in high enough numbers that it is feasible to learn more about even the jueniles of the community.

This is important research because rays are common bycatch in pelagic overfishing. Understanding the rate of maturation of this species can help us understand how quickly the population is indeed shrinking. (No matter the findings, it’s pretty clear that oceanic rays are highly vulnerable.)

Over 350 rays passed through FGBNMS and were counted for this study: 104 were size-estimated using various methods. The animals averaged a disk width of 2.25m and tended to be on the larger side (median 2.12m). Most of the measured rays were classified into one of two currently known species, but a handful seemed to either be of a new species or were not identified as either.