Lakes and Oceans

Awesome xkcd cartoon today about the relative depths of lakes and oceans.

 

Whale Tail

This is the tail end of a baby Humpback Whale who cruised past us, when I say cruised I mean mobbed us, three people go hit (there was no damage). I caught a picture of its’ tail which was about 5 feet wide.

You can see the front part of the whale here.

Eye Contact

I had the opportunity to get on a boat going to the Silver Banks which are located north of the Dominican Republic. There was a group cancellation and I jumped on (there is usually a two year waiting list for this trip.)

Humpback whales migrate from the North Atlantic down to the Silver Banks to raise their young for three months at the start of the year. So there is an opportunity to get in the water and swim with them.

This is a young calf (still 12 feet long) who came right up to me to check me out.

It has been a long time since I posted something about diving, in fact it has been a very long time since I had been diving until a couple of months ago when a block cancellation opened up room on a boat to the Silver Banks to snorkel with Humpback Whales.

This is a very sought after trip, the whales are on the Silver Banks for the first three months of the year, and the number of people who can visit is strictly controlled (880 people a year).

This was a wonderful trip, and I managed to get a few pictures.

 

NewImage

Study Confirming The Obvious About Sharks

Ars Technica does a good job of summarizing a study on declining shark populations. However I think the study is too tentative in identifying causes and effects. Simply put sharks are disappearing because of overfishing (for shark fins, once those are removed from the shark, it is thrown back in the sea to drown). The numbers being fished every year are up for debate, the office number is 38 million, realistically that number is probably closer to 70 million, and I have seen estimates of 100 million (probably for effect.) Over the past 20 years there has been a 50% decline in the global shark population. Even if fishing were to stop now, it would take a long time (a human generation or more) for stocks to get back up to ‘normal’ levels (say the numbers we had 20 years ago) because sharks take a long time to reach sexual maturity.

The effects of this reduction in the top predator are already being felt. For example there has been an increase on the stingray population which creates pressure on the mollusk population, and a large increase in the number of Humboldt Squid in the sea of Cortez. And for all intents and purposes, the Mako shark population on the east coast of the US is now non-existent.

Unfortunately the trends are clear, if this de-population goes on, sharks will be reduced to very small numbers in my lifetime, and the best chance to see one will be either the aquarium or in pictures.

 

Good-bye Shark Week? Large sharks in decline due to fishing:

Sharks have been honed into efficient predators by over 400 million years of evolution, but that didn’t prepare them for commercial-scale fishing. Sharks, skates, and rays are fantastically abundant in unexploited parts of the ocean, but a new review shows that even light fishing—both targeted at sharks and other species—can send populations into a tailspin. Large, top-predator shark species appear to suffer the most, and their dwindling numbers are drastically affecting many marine ecosystems.

Utila Sunset

This is not strictly a scuba diving but it was taken from the sun deck of the dive boat we were on. I was talking to some friends who had their back to the sun so I was watching the sun going down and I had to stop the conversation and pick up my camera to shoot this as the sun was turning the sky and the water to fire. I took about 15 shots and this is one of the better ones.

It was the penultimate evening of the trip, we had one more night dive that evening which got called off because the water was full of sea wasps. Actually strictly speaking the dive was not called off, the captain told us we were welcome to dive if we had the guts, but given how many sea wasps there were none of us had the guts. There were hundreds of them in the first couple of feet of the water column.

Goodbye Bluefin Tuna

I was deeply disappointed to see that the UN rejected a ban on the trade of bluefin tuna on March 18th (see “Bluefin tuna: Eaten Away” in the Economist and “U.N. Rejects Export Ban on Atlantic Bluefin Tuna” in the NY Times). The article highlight the voting shenanigans that we used by the Libyan delegation to effectuate this rejection.

Let’s face it, with idiots like that in charge of conservation, bluefin tuna is as good as extinct. From the Economist:

The outlook for the bluefin tuna is not good. Scientists already agree that the population is crashing, and that quotas allocated to fishermen remain too generous to give any reasonable degree of certainty of a recovery. The extent to which illegal fishing can be brought under control will also have a big impact on whether the population has a chance of recovering.

What I can’t understand is that the countries who rely most on fishing for food and trade are the least likely to implement sound fishery management practices. I have to wonder if these people have given thought to how they will make a living once the fish are all gone?

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