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husbandry sta¤ gently fended them away any time they looked as if
they might bump into the walls or the windows. Fortunately, the two
aquarists who were standing by with wet suits and scuba gear weren't
needed to help the sharks swim.
Two days later Bob and Neil called to say they had two more sev-
engills and would be coming in that night. Those sharks also did well.
All in all, the trip was a great success. Three months before the aquar-
ium was scheduled to open, we had four healthy, large sevengills cruis-
ing around the Monterey Bay Habitats.
The next step was to get them to take food. None of the current hus-
bandry sta¤ had ever worked with sevengills or, for that matter, any
large sharks. What's more, and not surprisingly, having these large, po-
tentially dangerous animals in the exhibit raised a certain amount of
apprehension on the part of the sta¤ and volunteer divers who would
be cleaning the windows, siphoning the bottom, and feeding some of
the invertebrates. At Steinhart I'd dived a number of times with the
sevengills in the much narrower Fish Roundabout, which had only nine
feet between the window and the wall of the tank. I'd found it quite
safe as long as I left the shark alone and didn't crowd it.
Partly to feed the new sharks, but also to show others that it really was
safe to dive with them, I decided to try a method I'd used before to
get food to new sharks, especially when they're outcompeted by speedy,
aggressive eaters like the yellowtail at Steinhart. Carrying a short
wooden pole with a dead mackerel impaled on the end of it, I posi-
tioned myself at the narrow part of the hourglass-shaped Monterey
Bay tank and waited until the first sevengill came by. I then thrust the
food in the path of the approaching shark so that it would pick up its
scent. My ploy worked: the shark opened its mouth, grabbed the mack-
erel, and gulped it down whole.
Many sharks, like the mako and the blue shark, depend on their
keen eyesight to provide information about the world around them.
Others, however, such as the tropical bull shark, the sixgill ( Hexanchus
griseus ), and the sevengill, live in dark, murky water where even good
eyesight isn't of much use. These sharks depend instead on an acute
sense of smell, which tunes them in to both living and nonliving food;
on the ability of their lateral line system to detect vibrations coming
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