Photo of the Week: July 04, 2011

Hi Gang!

This week's POTW comes from the Philippines where, lucky me, I have been diving with Captain Steve, his wife Jan, and a gang of other divers that have dived with Hawaiian Rafting Adventures over the years. We have been diving at both Dumaguete and Puerto Galera, two highly acclaimed areas, and no doubt, we have had a blast seeing creature after creature that makes you scratch your head in utter amazement. It really has been two weeks of "wows” and “what's that's?" and fun. A fun group of people and great diving. It’s hard to ask for more.

This week’s POTW is an image of a pair of Coleman shrimp, Periclimenes colemani, on a fire urchin. The shrimps described in the genus Periclimenes are sometimes referred to as “anemone shrimps”. However, anemones represent only some of a number of animals that these shrimps associate with.

The fire urchin, Asthenosoma varians, is venomous. Coleman shrimp take advantage of the venomous spines to gain protection. As you can see in this week’s POTW, the shrimp clear an area on the urchin (by pinching off the spines) that is just big enough for the shrimp to create a protected area for themselves. The surrounding spines provide protection for the shrimp. The shrimp are, therefore, classified as parasites, but the urchins do not seem to be severely impacted despite the removal of some spines and the fact that the shrimp feed on the urchins’ soft tube feet and their “tentacle-like arms”. 

Coleman shrimp are commonly seen in pairs. The female is the larger sex. The pair is believed to be monogamous. Coleman shrimp are so named because they were first documented by the noted Australian naturalist Neville Coleman, the author of a number of publications about marine life. 

The key to finding a pair of Coleman shrimp is to first find a fire urchin. When you do, you will want to slow down and look closely. Not every fire urchin serves as a host to a pair of Coleman shrimp, but if you look at a number of fire urchins the odds will probably produce a photogenic pair of these crustaceans.

This week’s POTW was captured with a Nikon 60 mm lens mounted on a Nikon D300 camera. While in the Philippines I wavered between using a 100 mm lens and a 60 mm lens. Both lenses are f/2.8 lenses, and both provide the ability to capture life size images, a shooting ratio commonly described as 1:1. The use of a 60 mm lens means that the photographer must get closer to the subject to fill a pleasing percentage of the frame with the subject and to acquire a life size image. However, if the photographer can get close it means shooting through less water, and in my case because I have an older 105 mm lens my 60 focuses much faster, especially in low light and on subjects that lack sharp contrast.

So much of diving in the Philippines focuses on small animals, and I have found that I can get very close to most subjects without disturbing them. So, I generally opted for my 60 mm lens.

The shot was lit by a pair of Ikelite DS 160 strobes. 

I hope you enjoy this week’s POTW!

See you next week,

Marty