Another hugely successful trip was made to Riley’s Hump in search of the
elusive spawning Mutton Snapper We made this trip in support of the National
Marine Fisheries Service Southeast Region, Beaufort, NC lab. We are spending
enough time at Riley’s Hump now to get these muttons dialed in. 19 scientists
and 7crew boarded the Mighty Vessel Spree at 4:30 Monday afternoon. After dinner
in town and RASS (don’t ask) training, we settled down for some briefing and get
to know each other time.
Tuesday we descended on Riley’s Hump like a herd of scientists with a mission.
Everyone was gung-ho and ready to find those snappers. The weather was calm, and
the attitudes were enthusiastic. Both would fade as the week went on. Along with
chasing muttons, part of the mission was to monitor coral growth at Riley’s.
This involves visiting 15 monitoring stations with data loggers mounted to them,
switching out loggers, downloading them, changing their batteries, and
re-deploying. This takes quite a bit of time out of our day. The diving is good,
with lemon sharks, bull sharks, unidentified gray sharks, rays, and marine
critters galore. Around 4PM, however, it’s time for the underwater sex show.
A female Mutton Snapper will rise off the bottom to about 60 feet of water,
along with her consorts. A group of 10-12 fish make this rise. She wiggles her
tail at them, and squirts between 1000 and 2000 eggs at the boys. Hardly able to
contain themselves with joy, they make a big spermy mess. The mess is big enough
to hide the whole group. They all swim around within the mess, mixing and
dispersing it. When it’s all over, the females want to cuddle, but the males
fall asleep. These aggregations seem to happen 2 and 4 days after the full moons
of June and July. More research is needed to determine if they spawn more than 2
days per month, or more than 2 months per year. This month, the dog snappers got
into the act too. They have a whole different way of doing things.
The dog snapper pair up together, and turn a brilliant white color. The males
nudge, herd, and bump the females while turned sideways like a flounder. He is
also busy running the other males off, as the gravid female smells good to them,
too. When the foreplay is finally over, she releases her eggs and he releases
his sperm together, they then settle back to the bottom.
This week, we saw spawning muttons, dogs, and ocean triggerfish. It was good
company and a fun group, and hopefully we’ll do it again next year.
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