MarineBio Newsletter 4
|MarineBio News||---||Ask MarineBio|
|Featured Species: Moon Jellyfish||Advice for Up & Coming Marine Scientists|
|Issues in Marine Conservation||The Sea Below: Diving Adventures|
|Current Research in Marine Biology|
MarineBio is pleased to announce the return of MarineBio Newsletters! Beginning with this newsletter, we plan to release 2 issues of the newsletter each year packed with updates about the site and information about marine biology, including conservation issues, feature articles on species, information about marine science education opportunities, and scuba diving. We welcome your feedback on the content of the newsletter and would love to hear what you're interested in reading! Send your comments to: Joni@marinebio.org.
We're growing!: MarineBio is working toward obtaining 501(c)(3) non-profit status, and is now using the MarineBio.org domain to inform visitors that we are a non-profit organization. You will notice a variety of improvements to the site, and there are many "behind the scenes" improvements underway to improve the speed and content capacity that are quite costly. We encourage you to visit our donations page to learn how your donation can help keep you informed and save our seas. Your contribution will help MarineBio to accomplish its mission to:
- Be the greatest source of the latest and most complete information about every marine plant and animal species online.
- Carry the wonder of the underwater world, as first shared by Jacques Cousteau, to all with access to the Internet, at no charge.
- Provide a platform for researchers to publish works and interact with a close community of peers and the world.
- Be a tool for Marine Biologists to stay up-to-date and communicate with others in the industry.
- Show that team work, boundless enthusiasm and imagination are what's really needed to produce a worthwhile online experience.
New species added: Ten new species have been added to the MarineBio database including: Basking Shark, Beluga Whale, Goblin Shark, Minke Whale, Moon Jellyfish, Northern Right Whale, Pacific Seahorse, Sei Whale, Sperm Whale, Twoband Clownfish, Whitetip Reef Shark.
Check out the videos!: New video footage of marine life has been added to MarineBio.org taken during the our 2002 trips to the Red Sea and the Galapágos. The new Twoband Clownfish page includes footage taken in the Red Sea of these remarkable creatures and their anemone homes, and you can see video of Common Dolphin riding a bow wave as well, also taken in the Red Sea. Video from the Galapágos trip includes the: California Sea Lion, Spotted Eagle Ray, Pacific Seahorse, Green Moray, Green Sea Turtle, Pacific Barracuda, Bottlenose Dolphin, Scalloped Hammerhead Shark, and the elusive Whale Shark.
Featured Species: Moon Jellyfish – Aurelia aurita
There are many species of jellyfish (cnidarians) of all shapes and sizes. One of the most common and most misunderstood is the moon jelly - Aurelia aurita. This jellyfish is common all over the world. Unfortunately, based on the reputation for painful stings of other jellyfish, the moon jelly is unnecessarily feared by swimmers, snorkelers, and divers. Like all jellyfish, moon jellies have stinging structures called nematocysts used for defense and to catch prey. Some jellyfish have nematocysts that are very poisonous, some even lethal. The moon jelly however is not capable of harming humans as its nematocysts are too small to penetrate human skin. A good rule of thumb with jellyfish is that if they have long thin tentacles (greater than a foot) they can probably sting you.
The moon jelly is shaped like an inverted shallow bowl the edges of which are shaped into eight scalloped lobes with a fringe of short hairline tentacles and four short oral arms. The color of the moon jelly is whitish to clear, and the adults have four horseshoe shaped sex organs visible on top of the animal that consist of both guts and gonads. These organs are usually colored purplish gray, yellow, or white, although sometimes they appear orange in color after feeding on brine shrimp. The body of the moon jelly consists of 96% water and can grow up to 15 inches in diameter.
Moon jellies feed on plankton by trapping them in their tentacles or in the mucus found on the surface of the body. The food is then transported to the digestive system by ciliary tracts (lines of microscopic beating hairs that act as conveyor belts).
As both sexes have gonads, they can reproduce both sexually and asexually. Female jellyfish pick up strands of sperm floating in the water released from males, and fertilize themselves internally. After fertilization the female releases planula larvae, which eventually settle onto the bottom (substrate) and metamorphose into the first stage of the jellyfish lifecycle, the polyp stage. Asexual reproduction occurs through the strobilation process in the polyp stage when jellyfish bud off asexually creating other individuals that will also metamorphose into the second stage known as the medusa stage.
Jellyfish are amazing creatures and amongst the most ancient of all life on Earth. They are classified as plankton, which by definition means any organism incapable of swimming against a current or, in other words, drifts. Although they do not have brains, hearts, eyes or nervous systems, jellyfish do have nerves that connect to form a net that enables them to swim by sending impulses to contract. The impulse to swim is intended to keep moon jellies close to the surface where they find the most abundant food.
A little known fact about the moon jelly is that it is capable of shrinking itself when it cannot find enough food. A ten-inch moon jelly can reduce itself in size to about an inch in diameter and will grow back to its original size when it receives enough nutrients.
Issues in Marine Conservation – Bycatch
For every pound of shrimp or prawns there are about 15 pounds of what's conveniently renamed "bycatch" that's killed and wasted needlessly. Bycatch are all kinds of fish, big and small, that are caught along with the shrimp but are not needed and usually die onboard and are then tossed back into the Sea. Bycatch is a common problem throughout the commercial fishing industry posing a serious threat many species and to our oceans' ecosystems.
Separating shrimp from bycatch, June 1969, NOAA
Hundreds of thousands of animals also die in fishing nets each year. Drift nets (also known as gill nets) and trawl nets, some of which are large enough to contain 12 jumbo jets, are the most damaging methods of fishing and are being phased out in many fisheries.
Marine mammals and other large animals can suffer serious injuries, often while still alive after becoming entangled in fishing gear: deep wounds, flesh wounds, severed beaks and fins, internal injuries, puncture wounds intentionally inflicted to make the bodies sink, and decapitation. Sharks often die because they are unable to move through the water to get oxygen to their gills, and dolphins and turtles often suffocate as well because they are unable to reach the surface for air.
The vast quantities of fish caught with nets also deplete species to the extent where they are in danger of extinction. Some species have already become extinct and many are seriously threatened. Some countries now ban drift and trawl net fishing in order to protect endangered species and to prevent bycatch. The fishing industry is increasingly aware of the damage caused by netting and of the need for alternative methods.
Deep sea trawling is particularly harmful to ecosystems because it strips the entire environment of all living things including ocean plant life. Continued stripping of deep-sea areas may cause species to become extinct before they have a chance to be identified by science. A solution to this problem must be developed in order to sustain deep-sea environments. One solution is to designate large areas of the deep sea as off limits to fishing.
In addition to the creation of protected areas, alternative fishing methods are being developed to sustain both the fishing industry as well as the marine ecosystem:
• Longlining: baited hooks attached to lines extending from the boat commonly used to catch swordfish. This is a sustainable method of fishing because it can target a specific species.
• Purse seines: nets used to capture entire schools of fish at or near the surface and are then closed by a drawstring. This method greatly reduces bycatch by targeting specific species within a school.
• Weirs: a method that consists of brush or twine fences anchored to the ocean floor. The fences direct the fish into successive enclosures, which mostly capture the species targeted.
• Fish traps: similar to weirs, but they are constructed with netting or wire and are designed to float near the ocean floor where stakes or pilings cannot be used.
• Jigging: a method that uses fishing line with lures that are continually jerked by hand or by machine attracting fish to the baited hooks.
• Harpooning: an old fishing method still used to catch large fish such as swordfish, shark and tuna. The harpoons are thrown by hand or shot from a mounted gun. They release a long line with a buoy at the end and a barb at the tip. The caught fish are then followed until they tire and can be hauled onto the boat.
• Hook and line: more common in sport fishing, and involves the use of fishing line and a rod-and-reel. The selection of the bait and fishing location facilitates the targeting of one species.
• Trolling: also uses fishing lines towed behind a moving boat.
There are a variety of organizations fighting to prevent bycatch from harming marine ecosystems including:
Charles Darwin Foundation, Inc.
European Cetacean Bycatch Campaign
Marine Conservation Institute
Monterey Bay Aquarium
The Ocean Conservancy
Whale and Dolphin Conservation Society
World Wildlife Fund
Current Research in Marine Biology: The National Oceanic and Atmospheric's Ocean Explorer Web Site
As the realization sets in that we know more about the moon than the oceans, more and more research is being conducted in our seas. National governments are providing more resources for research and a wider variety of academic institutions are providing the means for scientists to help us learn more about marine science. The US National Oceanic and Atmospheric Administration's (NOAA) Ocean Explorer site provides visitors with a comprehensive look at current marine research including history, technology, projects, and education; and provides an extensive image gallery and library. MarineBio plans to expand its marine biology research pages in the near future as we feel research is critical to affect the policy changes needed to save our seas.
One of the NOAA's 2003 projects, in partnership with the Harbor Branch Oceanographic Institution, explored the Gulf of Mexico for bioactive compounds from marine organisms that have potential for the development of new medicines and/or biomedical products. The project had three primary objectives the first of which was to isolate samples from the area that may be used in the development of new compounds to study, diagnose and treat human diseases. An ancillary benefit to this research includes the study of these samples to develop alternatives to harvesting bioactive compounds from nature such as reproduction of these compounds in a laboratory setting. Research is being conducted on alternatives such as chemical synthesis, microbial fermentation, marine invertebrate cell culture, molecular biology, and aquaculture of bioactive marine organisms.
The second objective of this project is to document the biodiversity of the deep water habitats in the Gulf of Mexico, particularly sponges, cnidarians, mollusks, annelids, echinoderms, ascidians, and microorganisms. The third objective is to provide public education and outreach programs via at-sea Web access, interactions with teachers and the media, and data dissemination via the Internet.
We encourage you to visit the NOAA's Ocean Explorer to learn more about this project and other NOAA marine research activities.
Ask MarineBio – Does Flash Photography Harm Fish?
Noora from the UK asks: How do fish react to bright light? Can they go blind or even die?
We searched for an answer in the literature and were not able to find one, so we went to the experts.
A marine biologist and expert in shark research told us that while the light itself does not harm the fish, there are some fish, such as sharks and rays, which have highly sensitive electrical receptors in their skin which they use primarily to detect prey. In sharks and rays these receptors are called ampullae of lorenzini and are most often found near the snout of the animal, although they are also present along the rest of the body.
It is possible that the mild to strong electrical fields generated by lights of both still and video cameras may give the animal an electric shock that can lead to muscle spasms and pain. It is unlikely that the animals are harmed long term.
There is also the chance that the bright lights may stun the fish making them more vulnerable to predators because they are temporarily blinded, similar to the way the bright sun hurts your eyes when you leave a dark room to go outside.
This question is also addressed by the makers of the Blue Planet video series. Click here for a transcript from a BBC chat with the makers of the Blue Planet for information about this question and the filming of the documentary series.
If you have a question for the marine biologist, please send it to us at: email@example.com.
Advice for Up & Coming Marine Scientists
One of the most common questions received by MarineBio from members interested in a career in marine biology is what schools offer post-high school education in marine biology and which ones are best? We encourage all of you with questions like these to check past replies in the What's it take for a career in marine biology? thread before posting a new question. Several members of the Plankton Board have offered excellent answers to this question, and we are very grateful to them for their help with links and information on marine biology education. We plan to feature specific academic institutions and the curricula they offer in future issues of the MarineBio Newsletter. A great education resource is the NOAA's Ocean Explorer cd rom. This cd provides the entire site's content through January 2003 so that you can explore the site offline (see the Current Research in Marine Biology above). To obtain a free copy of the cd visit: NOAA Ocean Explorer: Education - CD-ROM.
The Sea Below: Diving Adventures: Galapagos
In November 2002, MarineBio's Founder, David, had the opportunity to visit the Galapágos Islands for two weeks of diving and exploring. The Galapágos National Park is located about 500 miles (805 kilometers) off the coast of Ecuador and consists of an archipelago of 13 major volcanic islands and numerous smaller islands making up an area of about 3,500 square miles (8,500 square kilometers). These islands are well known as one of the world's most magnificent ecosystems. To protect the biodiversity of the area, Ecuador established The Galapagos Marine Reserve, a 51,351 square mile (133,000 square kilometer) protected area.
The Galapagos are widely known as the place where Charles Darwin found his inspiration for "On the Origin of Species by Means of Natural Selection," a book published in 1859 on the theory of evolution, which created a great deal of controversy. Darwin's radical ideas were attacked by the Church, but today they are widely accepted as the only explanation for the diversity of life on earth.
The diversity of life in the Galapagos is astounding – both underwater and on land. Because this area is so pristine, many animals have no fear of humans.
On the first land tour David was greeted by an overwhelming number of sea lions, many of which were mothers with young pups. The animals were remarkably unafraid of the group. Additional land visits provided opportunities to see an abundance of marine iguanas, giant tortoises, a wide variety of birds, Galapagos penguins, fur seals, and of course, more sea lions.
The famous Darwin and Wolf islands are found in the northern Galapagos and are located about 135 miles away from the main island chain. During several dives at a site known as the Arch off Darwin Island, large schools of scalloped hammerheads, majestic spotted eagle rays, and a black tip reef sharks were seen. There were also many green turtles and curious dolphins which seemed to be keeping an eye on the divers.
David was very lucky to spot an elusive whale shark at 90 feet during a dive near Wolf Island, and fortunately he was armed with an underwater video camera. The footage is rare and beautiful as these creatures are difficult to find.
During the dive off Cousin's Rock, known for its Pacific Seahorses, David videotaped sea horses, a variety of colorful starfish, damsel fish, spotted eagle rays, Pacific barracudas, crabs, gobies, and the playful sea lions. The female sea lions were incredibly intelligent and seemed to enjoy the divers as much as the divers enjoyed them!
Much of the new video footage on MarineBio was filmed during David's trip to the Galapagos. Video from the Galapagos trip includes the: California Sea Lion, Spotted Eagle Ray, Pacific Seahorse, Green Moray, Green Sea Turtle, Pacific Barracuda, Bottlenose Dolphin, Scalloped Hammerhead Shark and the Whale Shark.
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