Fish Identification: Black Triggerfish

Black triggerfish are also known as black durgon, but should not be confused with their close relatives the Indian Triggerfish and the Black-finned Triggerfish.

Physical description

[Black Triggerfish][]
Black durgon average about 12 inches in length, but can grow as large as 14 inches.

They have the common triggerfish body shape: oval with soft dorsal and anal fins of equal size. Both fins are white at the base, while the rest of the black triggerfish appears black. I say appears, because taken out of water and put under light, the fish is colored dark blue / blue-green.

Geography and habitat

Black triggerfish live in tropical waters across the entire globe. They are found in practically all depths.

The fish is also usually solitary.

Further reading

Wikipedia
Freshmarine.com
Animal Pictures Archive

[Black Triggerfish]: http://thedivingblog.com/uploads/2010/04/black_triggerfish.jpg


Hooded Vests

I love hooded vests. They are one of the most versatile pieces of equipment I own, for a few reasons:

[Hooded Vest][]

  1. They keep you extra warm. This one's obvious. Hooded vests make any wetsuit useful for another 10 degree drop in temperature, so factor that in when choosing a wetsuit. It's also useful to warm you up at the end of a week of diving.
  2. They are easy to pack. Taking all my gear isn't always an option for trips where diving is not the sole purpose, but I'd like to get a dive in if possible ...

Surviving Sharks

I saw this episode while skimming through Netflix's Watch Instantly selection. It's from something called "Shark Week" on The Discovery Channel. I was intrigued by the title and decided to watch it.

It's hosted by Survivorman, who I have never heard of.

In short, this show was lame, and a waste of 45 minutes. From the overdramatic introduction by the host to the bad B-movie soundtrack, there's not much I could recommend about this program.

The show consists entirely of bad shark stereotypes. The introduction talks about reef sharks being killers and how dangerous it is ...


Fish Identification: French Angelfish

Today's fish is very tropical in terms of appearance as well as location. I see these guys all over the place in the Caribbean.

Physical description

[French angelfish][]
As their name suggests, french angelfish are members of the angelfish family, and so have the familiar large, roundish body that is also flat. They can grow in length up to 16 inches (about 40 centimeters).

Baby and adult french angelfish are different in appearance. Juveniles are black with nearly-vertical yellow stripes across their body, five or so.

As they grow, french angelfish lose their stripes. They retain an overall dark greyish body ...


What is Backscatter?

In underwater photography, backscatter is light that reflects off particles in the water resulting in specks of light in the photo. Usually this light comes from an on-camera flash, although any bright light from the direction of the camera can do it. Particularly unclear water can exacerbate the problem.

There are mainly two ways of addressing the problem:

  1. Don't use a flash / strobe from too far away

    "Too far away" is dependent on the visibility of the water, with higher visibility tolerating flash from slightly farther distances. However, anything above 3 ft / 1 m will probably have backscatter.

  2. Separate ...


Deep Descent: Adventure and Death Diving the Andrea Doria

[Deep Descent: Adventure and Death Diving the Andrea Doria][]
We've all heard by now that only 3% of the earth's oceans have been explored. What treasures lay undiscovered in the remaining 97%? For recreational divers, this trove of wrecks and artifacts will remain outside the boundaries of our skills and training, but for many, the lure of the deep is too much to resist. Deep Descent is the story of those who succumb to this temptation---whether for the promise of unmolested china or the glory of being in an elite group of divers. In particular, the focus is on one such prize: the Andrea Doria.

The SS ...


Leaky Masks

Few things ruin a dive as quickly as a poorly-sealed mask. I had this problem the other day, and it disrupted my dive by being distracting and making me run through my air supply by constantly clearing it.

I started playing around with something that I think helps a little. Next time your mask is leaking water, instead of clearing it as usual, exhale a little stream of bubbles out your nose. Sometimes this will keep a small leak cleared by forcing the water out of the mask.

This approach managed to keep my mask clear without costing my air ...


Cheap Pocket Masks

When you train to be a Rescue Diver, and especially when you reach a professional level, you will be expected to have a pocket mask.

I looked around at some before ordering, beginning at scuba dive shops. I noticed that they aren't so cheap. Neither are the official Red Cross masks.

It didn't take long until I found these pocket masks at Amazon. \$8 each is the lowest price I found, and much lower than the price quoted at dive shops. As long as it has an O2 inlet and covers the mouth / nose, you're good.


Overweighted

Yesterday I overhead a man at a dive shop. He was complaining to his wife that he felt he was carrying too much weight on his dives. In his words, "I'm overweighted for the beginning of my dive, but if I carry less I'll balloon to the surface near the end of my dive. I start to feel it when I'm down to about 1200 PSI."

I say he's not overweighted, but rather weighted just right. If you remember how to do a proper buoyancy check, you'll recall that you do it with a near ...


Scuba Diving Insurance

The time has come. I've been toying with the idea for a while, but I've finally taken the plunge and signed up or scuba diving insurance.

Why insurance?

I dive more than three times a year, and plan to dive frequently in the future. It's said that the only way to prevent decompression illness (DCI) is to not dive, so it makes sense that the more you dive, the more risk you incur. You can follow every table or computer to the letter and still get sick.

I know I sound like an insurance salesman, but when ...