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Old 01/11/2008, 03:11 PM   #5
Gonodactylus
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Join Date: Aug 2001
Location: Berkeley, CA, USA
Posts: 5,024
Whenever I go into the field, I always take a dive light and net. Each night, particularly a few days after the full moon until the new moon, I try to spend an hour or so standing in the water with the light submerged and pointing out to sea. Many stomatopod larvae and postlarvae are attracted to light the night that they settle. As they arrive at the light and swim up the beam, I scope them up with the net and drop them into a bucket of sea water. Most stomatopod larvae have a translucent bluish white color in the light and are easily identified, but even on a night with waves and muck in the water, occasional sweeps of the net in front of the light usually produces a few stomatopods. When I'm finished, I sort through the night's catch and save any species that I haven't seen before or that I want to rear. Most are small (8-15 mm) and are easily transported back to Berkeley in 1 oz. plastic bottles with a half an inch of water in the bottom. They can last two or three days without opening the bottle or changing the water.

While stomatopod larvae are extremely difficult to rear, last stadia larvae that usually molt to postlarvae the night of capture (squillids, lysiosquillids) or postlarvae that are still up in the water column (gonodactylids, pseudosquillids) are quite tough and easy to rear. Burrowers can easily dig a burrow in a few inches of sand and they feed readily on live brine shrimp, but also will take frozen brine, mysids and cyclops.

I usually bring back 50-100 and rear those that I can't identify - or maintain specific species needed for experiments and observations. For example, some of the most abundant larvae in the water column in Moorea and Lizard Island are Pullosquilla thomassini and P. latoralis. I can catch dozens on a good night, rear them to sexual maturity (3 months) and look at sperm precedence and mating behavior having guaranteed virgins. If I collected adults (much harder), I could not be sure that they hadn't mated prior to capture.

If you are interested in rearing postlarval stomatopods and plan to visit a tropical marine coast (Hawaii, Florida, French Polynesia, etc.), it is worth a try. Even if you don't collect stomatopods, there is always something fascinating turning up in the bucket. My only words of warning are to wear a stinger suit since you will be standing motionless in chest deep water and the light attracts all sorts of things ranging from cubomedusae to fish lice.

Roy


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