New Jersey Scuba Diving

Hydroids

Hydroids

Masses of hydroids adorn many of the offshore wrecks, mixed in with anemones, sponges, mussels, coral, and algae. Hydroids are the most primitive Cnidarians, closely related to Hydromedusae, and display the most even split between the sessile polyp stages and free-swimming medusa stages, which are quite small and common.

The common Pink-Hearted Hydroid Tubularia spp generally grows in rounded tufts up to 6" across. Siphonophores are free-living hydroids that are often highly venomous, although most attached forms are harmless to humans.

Hydroids and nudibranchs — Hydroids carpeting a reef structure. Look for tiny nudibranchs within the tufts, feeding on the hydroids.

Hydroids — Pink-Hearted Hydroids Tubuleria spp.

Hydroids — Extreme close-up of a single "bud" of a Pink-Hearted Hydroid.

Snail Fur — These Hermit Crabs are covered with Snail Fur - Hydractinia echinata.

"Snail Fur" is a hydroid that grows as a pinkish fuzz only on shells inhabited by hermit crabs. Living snails that plow through the sand or empty shells that tumble with the waves and currents are not suitable homes for Snail Fur because of the abrasive action of the sand. But once the shell is commandeered by a hermit crab, most of its surface, except where the shell is dragged along behind the new homeowner and scrapes the sand, is kept out of the sediments and is available for colonization by the hydroids.

Snail Fur — Close-up of "Snail Fur"

Hydroid anatomy — Hydroid anatomy, greatly magnified

Herb Segars Photography

Hood, Gloves & Boots

mitts

Diving gloves should be close-fitting, with long, gusseted, zippered, or Velcro gauntlets that overlap your suit sleeves. This is especially important with a drysuit, since the glove will protect the delicate wrist seal on the suit. Thin tropical gloves are of very limited use in the north - your gloves should be at least 5mm thick. Three-fingered mitts are much warmer than five-fingered gloves and are really not much clumsier. They are also much easier to get on and off, which makes me wonder why so few people use them. A little spray soap will make any glove easier to get on.

A hood is critical for maintaining warmth in the water. A good hood will be as close-fitting as possible, and have a generous collar for tucking into your wetsuit, thin skin-in seal around the face, and baffled vents in the top to release bubbles. A neck skirt is much less necessary with a drysuit, but it is a simple matter to cut one off if you don't like it. A neoprene cold-water hood should be at least 5-6mm thick.

The face-hole of a hood should be as small as possible - there is no reason to expose any skin here. The face seal of the hood should overlap your mask skirt, with just barely enough room below for your regulator. You can always trim out a too-small face-hole, but a too-big one pretty much negates any other good qualities a hood may have. Ideally, with mask and hood on, you should expose a small patch on each cheek, and no more.

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