The Carribbean Reef Squid

fig. 1 Caribbean Reef Squid. Photo in the Public Domain

I went snorkeling yesterday with my hubby at Secret Harbor on the East End and one of the many forms of sea life I saw was the Caribbean Reef Squid (Sepioteuthis sepioidea). Now you may not have realized it yet, but I have a thing for invertebrates, so I was inspired to do this post. Plus, I had some groovy lab drawings from a squid dissection that I labeled on the compy for you. If you have any questions about the functions of any of the parts labeled, just let me know so that I can answer any questions for you. This is just the basics of this really alien and beautiful creature.

This squid is commonly found throughout the Caribbean and Floridian waters. They are usually found in shallow waters (1 meter or less) and are commonly seen in schools. I usually see between 5 and 15, but apparently will congregate in groups as large as 40. They are mollusks so, believe it or not, are related to the Queen Conch I posted about last week. Since they are further classified as cephalopods, they are more closely related to octopuses, cuttlefish, nautiluses and more. They are quite pretty and many time I have seen them flash colors at each other or in time. They are very colorful, almost iridescent creatures. The speed of color change in them is quite fast as well. In fact, they can change color much faster than a chameleon.

They swim (or hover) using the fins (click image below for larger view) on the sides of the mantle. If they need to get away quickly, they use a form of jet propulsion. If they still can't get away, they ink.

When they aren't hovering, they eat. They eat a lot. The Caribbean Reef Squid, like most squid can consume almost 50% their body weight in food a day. They are carnivores and eat a variety of prey including crustaceans, small fish, and even other mollusks.

fig 2. exterior of squid

One of the things that makes squid and cephalopods so interesting to study is their fantastic sight. The reason they are so studied is they are not even close to being related to vertebrates, yet process images similar to us. This means that their sight and eyes evoloved independently. The main differences are the ammount of visual pigment. They usually have one, we have three. They pretty much only see in greyscale, which is suprising considering the amazing display of colors they put on for us! There is one exception, however, but we won't complicate things. You can learn more about the coevolution and how their eyes work here.

fig 3. internal anatomy of male squid

Squid are know to be "weed like" in how they grow and reproduce. There are only about 800 species but in terms of production can keep up with fish. This makes fish an incaluable resource globally. The common market squid in Southern California (Loligo opalescens) alone is responsible for about $20 million in revenue a year. That is just the fishery side as well. That does not include uses for its ink, the money made in restaurants that sell it, or the money made from bait and tackle, etc. Due to its fast rate of reproduction, it is alsoconsidered one of the more sustainable types of seafood you could eat. Many questions have yet to be answered though. We don't know where many of these species spawn and just how many are out there. There was a great article published that attempts to show the effects of squid fishereies.

Besides all the info I just gave you, did I mention that they are awesome to swim with? I've only seen them at a few beaches here and absolutely everytime I see them, it's mesmerizing.

I hope you enjoyed my sketches. Happy learning!

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Gift of Plenty: Aquaculture News

We all know the world's oceans are of great importance, but there were two articles that caught my attention today while carousing the web.

One article from Science Daily was about how marine algae can be used as a new source of biofuel. Since oil seems to be on everyone's minds these days, it is no wonder scientists are looking elsewhere for our fuel needs. The research I am speaking of was conducted at Scripps Institution of Oceanography at UC San Diego. This is an enormous undertaking and as was written in Science Daily:

The prospect of squeezing billions of gallons of biofuel oil from marine algae is enticing, but to transform tiny lime-green-colored plant-like organisms into a viable and realistic fuel option, they must be tested and grown on a massive scale. Intermediate-sized, and eventually immense, algae production sites will be required to produce an economically relevant quantity of algae-based oil for biodiesel fuel in cars, trucks, and airplanes.

However, this is still a step in the right direction.

Another article about our worlds oceans was actually about the future of aquaculture and is from Biology News. In it, scientists and experts speculate that aquaculture will be the fastest growing food production system. Experts state that even though there are some potentially harmful effects of aquaculture, when implemented properly, fish farms can greatly lower the impact on over exploited wild caught. One tidbit that I found fascinating:

Finfish, mollusks, and crustaceans dominate aquaculture production; seafood exports generate more money for developing countries than meat, coffee, tea, bananas, and rice combined.

We really should take care of our "breadbaskets." Sure there is the aesthetic quality, but there is so much more at stake than that.

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Save the Queen... Conch, That Is!

I put a desktop picture up I found in our underwater photo archives and it's so cute, I decided to do a post on it. Previously known as Strombus gigas and now Eustrombus gigas, it is commonly known as the Queen Conch (pronounced konk) and is the species I will be talking about today.

Conchs are gastropods and means they are closely related to snails and a little more distantly related to squid as squid are mollusks as well. Here in St. Thomas, they can be found in shallow (less than 10 meters) water with sandy substrate mixed with a lot of Thalassia testudinum also known as turtle grass. Yes, it is called turtle grass for a reason and we will save that for another day. I go conching here (not to harvest, but for research) at Brewers Bay by the university. You can see in the picture provided, this guy is hanging out in sand and grass. For more fun, if you click on it, you will see his eyes poking out. Super cute. Anyway...
Most people that know anything about conch know that they will "attack" you. It's sort of true. You see, conch, like many gastropods, have an operculum. This is simply a covering at the bottom of his foot that seals the shell closed. If you have ever looked at marine snails or whelk, you will have seen this. In the conch it is particularly long and claw like. They will use it at times.

Another feature of their anatomy, and arguably the most dominant, are their spiraled shells. Many people are familiar with conch shell horns and the like. They are quite beautifully pink on the inside and are prized by shell collectors. Conchs also produce pink pearls that are very collected.

Locally, they are prized for their meat. We have conch fritters, conch stew, buttered conch and more. It is quite tender and yummy. However, this beautifully shelled animal is threatened. Illegal harvesting has devastated the population of conch in our waters. They are protected in Florida and in the Virgin Islands are harvested only certain times of year and must be a certain size. "Lip-less" conchs cannot be harvested as they are still juvenile. The rules are as follows:

A quota of 50,000 lbs per year. After the quota is reached, the fishery will remain closed until November 1st of the following year. A limit of 200 conch per boat for licensed commercial fishermen. A limit of 6 Conch per person for recreational fishermen and a total of 24 conch per boat. A closed season from July 1 until October 30. All conch must be landed alive and in the shell. No conchs may be possessed which are less than nine inches in length or less than 3/8 inch lip thickness. Fishermen must report their landings monthly to the Division of Fish and Wildlife.

Also keep in mind that there are times of year to harvest them. If we don't keep track on what we are doing now, we may not have them to enjoy in the future. They are already in serious decline and that is why these regulation are in place here. In Florida, they are considered threatened now and harvesting is prohibited in the majority of US waters. Even if you see an empty shell, try not to remove it as many species of marine hermit crab use these shells as well. I have reported illegal conching and it is quite easy. Remember, in the continental United States, harvesting is illegal. you can contact any natural resources division in your state. If you are in the USVI you can call DPNR at (340) 774-3320 in St. Thomas and (340) 773-1082 in St. Croix.

You can find out more at NOAA and at your local DPNR website.

Book used as reference:

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Seeing Stars!

I realized that after doing a few Name That Creature posts on Facebook that I should really make sure many of the creatures featured have a post on Potspoon! to make it easier to look up. First on this list of creatures I have skipped is the reticulated sea star or the cushion star, Oreaster reticulatus. Adults get beautiful reds, browns, and yellows that are striking and easy to spot while snorkeling or diving. They can also reach sizes of 50 cm (almost 20 inches).

This sea star is very common in the western Atlantic and is a very visible creature in sea grass beds throughout the Caribbean. Since they spend much of their lives in sea grass beds, the juveniles are green in color to blend in with their surroundings. They rarely hang out in deeper waters. Here in the Virgin Islands you will find them amongst the Thalassia testudinum beds. If you recall, T. testudinum is referred to as turtle grass and is also where you commonly find our friend the queen conch.

Hanging out in these turtle grass beds allows them a diverse diet consisting mainly of sea sponges that wash in from reefs and various forms of mollusks. To eat, they actually put their stomachs out of their "mouth" then digest partially what they are consuming. When ready, they suck their stomachs back inside!

Like is the norm for echinoderms (although exceptions always seem to pop up), they use a water vascular system for structure and to use the tube feet they move around with. Believe it or not, these guys are related to urchins and sea cucumbers! There are many reasons how, but perhaps we will save that for another post!

Now you know a basic rundown of the amazing cushion (or reticulated depending on where you get your info) sea star. Feel free to leave any questions in the comments!

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About St. Thomas

In case you haven't figured it out, I live in St. Thomas, VI. We are a part of the United States just located in the Caribbean. The Caribbean (for all us science types) is a tectonic plate all its own and the collision and interaction of this little plate with other larger ones is how the Antilles were formed. Because our islands with the rest of the ones in the Caribbean form a chain that acts as a barrier for the fierce Atlantic, the Caribbean Sea is calm and tranquil pretty much consistently.

View from Annaburg Plantation, St. John. Copyright 2007 M. Moya

Pretty, I know. It's not just the scenery that is nice, or the trade winds that keep the temperature mild. Below the surface is a bunch of really beautiful reef. The reefs in the Caribbean are predominately 70 different species of reef building coral, a ton of sponges, crustaceans (think crab and shrimp), mollusks (think escargot and clams)and various other invertebrates. They are also home to hundreds upon hundreds of species of fish, turtles, and other chordates (more on that some other time).

Reef, Gorgonian, and Bait Fish Highway. Lerkenlund, St. Thomas. Copyright 2006 M. Moya.

On land we have some interesting critters as well. About 2,000 species of bug and insects (that includes really pretty butterflies and amazing rhinoceros beetles) also call St. Thomas home as do numerous other types of animals like wild donkeys, deer, boar (although not so much on St. Thomas as St. John now-a-days), iguana, birds a plenty, bats, mongoose, snakes, chickens (they deserve a separate listing than birds) and lots of other fauna.

Iguana in Papaya Tree. Bonne Resolution, St. Thomas. Copyright 2006 M. Moya.

With all this we are still having our problems. Due to over development (living here seems to be prime real estate), our native plants are disappearing and animal habitat is all but gone in places. The snakes are all but gone, we are having a heck of a time breeding the local butterflies as most of the host plants are being removed, the parrots aren't coming back like they should... the list goes on. With all the beautiful scenery and natural environments, it's a shame we can't focus our tourism around this a bit more. Granted there are lots of dive spots, but what of our mangroves and tropical dry forest? What of the gallery forests in out "guts" (guts are temporary waterfalls where freshwater drains off the bedrock)? I think people would want to see this. Maybe it's just me.

Me and my doggy on the beach at Lerkenlund. Copyright 2006 M. Moya.

I enjoy finding the few place left here that haven't been developed, where the runoff from the building hasn't destroyed the reefs, the parrots still sing, and the mangroves are uninterrupted. I love it here, and I think everyone who comes here on vacation should support eco-tourism and the University, so our local government can see what people really enjoy is the pristine.

All Photos by Marizela Moya are licensed under a Creative Commons Attribution-Share Alike 3.0 United States License.

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