MarineBio Newsletter 10
Featured Species: Octopuses!
Issues in Marine Conservation: ECOSYSTEM-BASED MANAGEMENT
Current Research: Marine Satellite Technology
The Sea Below ~ Expedition :: Honduras
MarineBio is pleased to bring you the 10th edition of our newsletter! We welcome your feedback on its content and would love to hear what you're interested in reading! Send your comments to: Joni@marinebio.org.
- MarineBio is pleased to bring you MORE wonderful underwater videos on the downloads page featuring footage captured during expeditions to the Galapagos and Red Sea.
- New Species! We invite you to check out some of the new species that have been launched since the last newsletter. We hope you enjoy them, and, as always, we invite feedback if you would like to contribute additional data or references. Latest species on MarineBio.org: Caribbean Reef Octopus » Common Octopus » Spotted Scorpionfish » Sea Lamprey » Trumpetfish » Giant Feather Duster Worm » Blue-footed booby » Blue marlin » Bonefish » Browse or Search All Species
- Marine Science pages: We've added a lot of information to the Ocean section on the science involved in studying the ocean and marine biology. We've designed this section to serve as an introduction to the various issues and disciplines related to marine biology under sections titled: Life in the Marine Environment, The Physical Ocean, The Structure and Function of Marine Ecosystems, and Humans and the Ocean: Resources and Impacts.
- Marine Life pages: There is a whole new section on Marine Life that includes information on topics including: The Naming of Marine Life: Marine Taxonomy, Forests of the Sea: Phytoplankton and Marine plants, Zooplankton, Marine Invertebrates, Marine Vertebrates, Structures and Adaptations to Marine Living, Grazers and Predators, Marine Life Cycles, and Symbionts, Parasites, Hosts, and Cooperation. As with all content on MarineBio.org, these sections are always evolving and we welcome all feedback.
- Donations! A sincere thanks to everyone who has donated through our donations page. Your generosity is helping us add content to the site more quickly so that we can continue to make MarineBio.org the best source for information on marine life on the Web. We continue to work toward becoming a bona fide nonprofit so that we can devote more time to MarineBio.org Projects and continue bringing the ocean to your desktop. Stay tuned!
- Thank you! We'd like to send out a huge thank you to the folks who are helping us make MarineBio.org better and better: Mary Carmichael for her fun and inspiring species writing, Tamara Elkhof for helping us bring you an introduction to Marine Biology 101 in the Ocean section, Mario Lebrato of the Southampton Oceanography Centre, Allison Gill of Marineteam.com for contributing beautiful photos of critters to enhance our species pages, and Josh Cocklin for helping submit new species. More about Contributors & Interns »
Featured Species: Octopuses!
Octopuses are one of the most well-known invertebrates of the ocean realm. These wizards of the sea of the Order Octopoda are incredibly smart creatures with remarkable abilities to outwit their predators and prey. They are probably the most intelligent of the invertebrates and are arguably as "smart" as cats.
Octopuses are found all over the world, predominantly around coral and rocky reefs while approximately 40% are considered deep-sea by Voss although these and other deep-sea animals are under studied. All species are marine, they are in all marine habitats. There are about 289 octopus species characterized by the presence of eight arms with more than 200 suction cups on each arm. If an octopus loses an arm, which often happens when they encounter predators, the arm will grow back. Most octopuses have soft bodies, and unlike some other cephalopods, the majority have no internal shell, so they are able to squeeze into small places while hunting and for protection from predators. The size of the opening through which they can squeeze is only restricted by the size of their beaks. A few octopuses in the Cirrina suborder do have internal shells though as well as two fins, though very little is yet known about these fascinating species. The octopuses beak is the hardest part of most octopus bodies which is used primarily to break through the external skeletons of crustaceans and the shells of bivalves.
Most octopuses have a variety of other tricky devices used for defense. They are capable of expelling thick dark ink, which allows them to confuse their predators while they make a quick escape. They also have an amazing ability to instantly camouflage themselves using specialized skin cells called chromatophores that reflect light and iridophores and leucophores that reflect and refract light. This capability makes them masters of disguise able to blend into their environment and become virtually invisible (see our movies of octopuses in the Downloads section for examples of this behavior). They also use their dynamic color-changing ability to communicate with other octopuses and warn predators.
The extremely poisonous blue-ringed octopus, Hapalochlaena maculosa, turns bright yellow with blue rings when provoked.
Mimic octopuses, Thaumoctopus mimicus, can not only camouflage their bodies to match their environment, this creature also has the remarkable ability to change its body to mimic other more dangerous species, such as lionfish or sea snakes, to deter its predators. When a predator gets too close and an octopus is forced to move, some eject a cloud of ink to create an effective distraction while they make a quick getaway. Some may also display dynamic color patterns to confuse predators. A. marginatus can impersonate a coconut while it walks along the bottom and can often be found hiding in coconut shells, and has has also been rumored to lift the coconut shell it's hiding in and wear it like body armor while it walks about. Abdopus aculeatus is another clever species that uses two arms for locomotion and can often be found disguised as a clump of algae drifting in the current.
Not only do octopuses have a variety of defense mechanisms, they also have a variety of feeding mechanisms. They're able to use their arms to reach out and grab prey, taking advantage of their numerous sucker cups to ensure that their prey doesn't escape. Octopuses generally feed on crustaceans, fish, and other mollusks. They usually feed at night using their excellent eyesight and sensitive touch to find their prey. To capture their prey, they either use their arms to grab it, using their suckers, or they spread their arms using the webbed skin between them to form a canopy to net their prey.
They often also secrete a poisonous substance when they bite to stun their prey. When they capture crustaceans or bivalves, octopuses will pry the shells apart using their arms or bore into the shell using the radula inside their beak, which is a like a tongue, often with rows of tooth-like structures.
Octopuses reproduce sexually with males having a specialized arm, commonly the third right arm, called a hectocotylus used to insert sperm packets, or spermatophores, into the mantle cavity of the female. In some species, the female octopus holds the sperm for weeks until her eggs are mature enough to fertilize. Once fertilized, the female lays her eggs suspended in strings from the ceiling of her den. The female does not eat while she minds the eggs, and after the eggs hatch most female octopuses die.
After hatching, about half the species of octopuses have larvae that drift in the plankton to feed on copepods and other larvae such as larval crustaceans while the other half are direct developers, starting life as miniature adults. They are vulnerable in the plankton environment as many predators also feed there. If the octopuses make it through the larval stage, they then sink to the bottom where they begin to feed on their regular prey.
Octopuses have a relatively short life span, with some species living for just six months. Larger species, like the North Pacific Giant Octopus can live for up to five years, but only if they do not reproduce because females die after her eggs are hatched and the males also die a few months later.
These incredibly smart creatures have demonstrated the ability to learn in science experiments where the octopuses were able to distinguish between shapes and recognize objects by touch. There are many tales of octopuses displaying intelligence such as opening jars with screw-on lids, leaving their tanks to feed in another and then returning to their "home" tank, etc.
Issues in Marine Conservation
Ecosystem-based management proposes an interdisciplinary approach to managing the sustainability of marine ecosystems. In recent years, it has become increasingly apparent that the sea cannot provide a limitless supply of marine resources particulary given the rate at which humans are depleting them. By overfishing, humans are altering marine ecosystems by decreasing biodiversity. Not only are target species being removed at a rate that cannot be sustained, non-target species caught as bycatch are being depleted further reducing species biodiversity, which is critical to a well-functioning ecosystem capable of sustaining all marine life. Existing marine resources do not perish or thrive in isolation; they are all part of an ecosystem made up of a complex web of characteristics and interactions that impact the survival of all the species involved. A comprehensive understanding of marine ecosystems is needed to prevent their depletion and destruction. This approach will help marine ecosystems thrive in healthy environments, abundant with marine life, so that marine resources remain available for the benefit of the planet as well as for human needs such as food, employment, recreation, etc.
The term “ecosystem management” implies that humans are capable of managing a marine ecosystem. On the contrary, most of the physical and environmental factors that affect marine ecosystems are beyond human control, therefore we prefer to use the term “ecosystem-based management.” Human impacts on marine ecosystems can only be managed through a better understanding of how human activity affects ecosystems.
The ongoing sustainable use of marine resources requires consideration of a number of factors that impact the structure and balance of a given ecosystem. For example, to determine which species and how many can be taken from an ecosystem, the following factors would need to be evaluated:
- Interactions of the target fish stocks with predators, competitors, and prey
Interactions among species are critical to the proper functioning of marine ecosystems. Overfishing a key species or impacting other species populations can dramatically affect an entire ecosystem or disrupt the balance to such a point that ecosystems collapse. Studies must be conducted to prove that removing target fish stocks will not adversely affect the ecosystems they inhabit.
- The health and abundance of target species
Marine species populations are inherently difficult to estimate, particularly in a widespread marine ecosystem. A solid understanding of historical population numbers ("shifting baselines") is required to correctly determine the health and abundance of current species populations. Larger species often targeted by commercial fisheries do not produce as many offspring as many smaller species, and are therefore at greater risk of extinction if too many sexually mature adults are removed. Their ability to recover is also often difficult to predict, and in some cases commercial fisheries have been surprised to discover that, even when catch limits were finally imposed, their target species had already been fished beyond the point of recovery. Other species, however, have shown a remarkable ability to recover and return to their normal population sizes. Gray whales, for example, were hunted to near extinction in the 1850's after calving lagoons were discovered and exploited, but they recovered. In the late 1930's when ship factories began to operate in the Pacific, they were nearly fished to extinction again, yet again they have recovered, largely due to protection by the International Whaling Commission (IWC). Studies have yet to be done to see what effect on Gray whale overall biodiversity past whaling activities have caused in terms of their species diversity, genetic diversity, and ecosystem diversity which are very different than simply the numbers of individuals in a given area.
- The interactions between target species and their habitat
In the past, the importance of the habitats of target species has largely been undervalued by commercial fisheries. In the interest of the commercial value of the immediate catch, bottom trawlers have destroyed habitats essential to the long-term health of many commercial target fish species. A single pass can destroy massive areas of fish habitat removing feeding and breeding grounds essential for the long-term viability of the target species and others that live there.
- The impact of commercial fishing on target species and their ecosystems, etc.
Not only can human impacts such as fisheries alter the viability of their target species, they also impact the health and viability of other species within that ecosystem. One of the problems that needs to be addressed through an ecosystem-based management approach is bycatch, which can severely disturb the balance of marine ecosystems by removing too many non-target species.
Not only is ecosystem-based management required to maintain healthy ecosystems in fisheries, it is also necessary to properly manage Marine Protected Areas (MPAs) and coastal marine ecosystems. MPAs are areas designated for special protection so that marine resources can be better managed. At 350,000 km, the Great Barrier Reef is one of the largest MPAs. An ecosystem-based management approach to MPAs is more effective than management of individual species, which has largely focused on assessing and maintaining population sizes and has often failed. Ecosystem-based management of MPAs shifts the focus from managing individual species to managing ecosystems, which protects habitats such as feeding, breeding, and nursing grounds critical to marine life survival and ensures that the structure of ecosystems remain intact and healthy. Designating ecosystems, such as coral reefs, as MPAs can be an extremely effective way to protect these habitats. Unfortunately, however, most MPAs do not exclude fishing and are therefore not as effective in preserving ecosystems and biodiversity as marine reserves.
Marine reserves, also known as “no take zones” differ from MPAs in that they are marine areas fully protected from potentially destructive human activities such as fishing, drilling, or any other extractive activity of living and non-living marine resources. They are an increasingly important and effective tool for marine conservation and ecosystem-based management. Marine reserves provide protection from habitat destruction and further depletion of over-exploited marine species. They are also much more effective in preserving biodiversity in general. By banning fishing in these areas, not only are targeted species protected, other species often caught and discarded as bycatch are also protected. Marine reserves are also very useful for research, collaborative management of resources, and establishing baseline data in undisturbed areas. More and larger marine reserves are needed, particularly the development of networks of marine reserves that protect key habitats for migrating species. Expanded use of marine reserves will benefit both conservation efforts and commercial fisheries as species are given the opportunity to regenerate and flourish and therefore repopulate overfished areas.
Ecosystem-based management for coastal marine ecosystems is also an effective way to maintain the integrity of these sensitive ecosystems, particularly given the broad range of stakeholders involved in these areas. Coastal marine ecosystems worldwide are where most commercial fishing is done and are also under increasing pressure by other human activities as more people move to coastal areas. The ongoing degradation of coastal marine ecosystems needs to be addressed quickly and effectively to preserve these extremely valuable areas and maintain their integrity. Ecosystem-based management of these areas requires collective decision-making by local governments, developers, residents, scientists, and conservation efforts based on ecological, not economic or political, parameters.
An interdisciplinary approach to ecosystem-based management will help science, industry, conservation efforts, and policymakers work together to protect the marine realm while simultaneously protecting their related ecological and biological, economic, social, and institutional interests.
How is ecosystem-based management implemented?
A typical ecosystem-based management approach might begin with the identification of stakeholders and their interests and concerns and values related to a particular ecosystem. These stakeholders must then work together to identify the major problems facing the ecosystem and develop effective solutions based on good science and/or the identification of high risk areas which require priority action (priority conservation areas [PCAs]) as determined thorough scientific investigations. Consensus on solutions needs to be reached and policies and/or activities implemented to manage the health of the ecosystem, which may need to be first mapped or divided to identify areas that need initial or further study, monitoring, or action.
This is a very general example of the steps needed for ecosystem-based management, and it is important to note that this scenario can become very complex. In spite of the potential complexity, however, coordinated management and protection of marine ecosystems will also help reduce duplication of efforts and, hopefully, resolve conflicts among stakeholders. The common goal is long-term sustainability of marine resources. Without an ecosystem-based approach and coordinated effort, conflicts will continue to erupt over resources as problems such as overfishing, habitat destruction, loss of biodiversity, and pollution continue to degrade ocean ecosystems the world over. Most marine ecosystems are currently at step 1 where problems are just beginning to be identified. Much more research is needed to effectively implement ecosystem-based management to conserve marine life.
The widespread implementation of ecosystem-based management is likely to counter many of the problems above, and allow marine life and their ecosystems to thrive and flourish as well as the humans that depend upon them.
Monitoring the health of coral reefs using satellite technology
Coral reefs worldwide are deteriorating at an alarming rate due to a number of factors including global warming, pollution, overfishing, and destructive fishing practices. New approaches to protecting coral reefs are needed on a global scale. The health of coral reefs is essential because they are home to the greatest concentration of marine biodiversity and provide food, recreation, and coastal protection around the world. In recent years, satellite technology has provided the means to map and monitor the health of coral reefs. Underwater survey techniques are both time-consuming and costly. Remote sensing technology, however, has allowed scientists to collected data on coral reefs on a geographic and time scale not possible before. It also allows for large areas to be monitored over time so that scientists can assess changes to entire reef ecosystems. Data collected from satellite images can include information about areas of high and low primary productivity, reef growth and erosion patterns, and the relationships between coral reefs and other ecosystems such as mangroves and beach areas.
NASA is sponsoring a partnership between remote sensing scientists, international agencies, and NGOs (non-governmental organizations) to develop baseline global reef maps to use as a starting point for future research. The baseline data will be used to determine what research is needed and how the data can be applied to help improve the management of coral reefs. NASA provides images from its Landsat 7 satellite that show healthy, living areas of coral as bright red areas and dying or bleached coral areas as gray areas. More than 5,000 NASA satellite images have been captured from over 2,000 coral reefs worldwide.
"Natural resource managers around the world desperately need maps of coral reefs and adjacent land areas. The current level of knowledge about such simple measures as the total area and locations of coral reefs in the world is not sufficient as a baseline for monitoring change. Regional studies attempting to identify the risk factors for decline of coral reefs are also faced with inadequate maps of reefs and adjacent land uses. At the same time, local managers clamor for detailed reef habitat maps for monitoring smaller scale changes in reef communities. These managers are making daily decisions that impact the health of coral reefs and the economies of the communities that depend on them." - Remote Sensing of Coral Reefs at NASA
The European Space Agency's Envisat Medium Resolution Imaging Spectrometer (MERIS) satellite is also being used to monitor coral reefs and has been reported to detect coral bleaching up to 10 meters below the surface. This satellite is capable of scanning all of the world's reefs every two weeks, which will be very helpful in providing scientists with timely data on the rapidly changing coral reef ecosystems. Hopefully this will soon help with worldwide coral reef conservation efforts.
"An increase in frequency of coral bleaching may be one of the first tangible environmental effects of global warming," states Dr. Arnold Dekker of Australia's Commonwealth Scientific and Industrial Research Organisation's (CSIRO) Wealth from Oceans Flagship program." The concern is that coral reefs might pass a critical bleaching threshold beyond which they are unable to regenerate."
The Sea Below ~ Expedition :: Honduras
We visited the Caribbean island of Utila, Honduras based on its reputation for diverse marine life, healthy coral reefs, and for the presence of Whale sharks that go there to feed several times each year. The mission was highly successful resulting in 2,700 underwater photographs, including Whale sharks taken on the last dive of our last day there. We also had the pleasure of meeting with the Whale Shark Oceanic & Research Center based in Utila, which is doing some unique and interesting work to protect both Whale sharks and their environment.
Utila is in the Caribbean Sea just 29 kilometers from the coast of Honduras at the southern tip of the Mesoamerican Reef, the largest reef in the Western hemisphere. Utila is the smallest of the Bay Islands, which also include Roatan and Guanaja. These islands are a diver's paradise, and Utila alone boasts more than 60 dive sites. Overall the diving was quite good. With the exception of minor coral bleaching in the shallower areas (though down to 15 meters at some sites), the majority of hard corals appeared healthy with many bleached areas apparently recovering with new small coral colonies starting up. There was an abundance of healthy soft corals, as well as a wide variety of sponges, including some of the largest barrel sponges we've ever seen. In some areas there appeared to be an overabundance of algae, however it did not yet appear to be jeopardizing coral health at the sites we dove.
We were disappointed that the visibility averaged only about 12 meters on most dives for the duration of our stay, although some dive sites were better than others. Coral spawning season was in progress, which may have been the culprit, but we were also told that this time of year visibility is “hit or miss” around the island for various reasons. Our favorite dive site on the island was “Black Hills.” This mound was home to a wide variety of reef fish including schools of Horse-eye jacks, Atlantic spadefish, Great barracuda, and Black Durgons. We also saw Nassau and Tiger groupers, several species of Damselfish, Hawksbill turtles, Indigo hamlets, mating Creole wrasses, juvenile Creole wrasses, French and Queen angelfish, Whitespotted filefish, Trumpetfish, Honeycomb cowfish, Smooth pufferfish, Balloonfish, Green and Spotted morays, Atlantic and Queen triggerfish, Spotted scorpionfish, Schoolmasters, French grunts, Gobies, etc. We also enjoyed some of the dive sites closer to the coast such as “Stingray Point”, “Silvergardens”, and “Madeleines” where we observed Spotted eagle rays, Flying gurnards, Conch, Hermit crabs, Garden eels, Peacock flounders, and Southern stingrays. There were several varieties of Parrotfishes as well including Stoplight, Rainbow, Princess, and Redfin. We dove “Blackish Point” twice and found its resident Midnight parrotfish more interested in chomping coral than avoiding divers, so we were able to get some beautiful shots of them. Although we searched high and low (shallow and deep!) for Utila's elusive sharks, frogfish and sea horses, we were unable to find any. The locals told us that there used to be lots of sharks but they have since been completely fished out.
As captivated as we were by Utila's vertebrate species, we were also impressed by the health and diversity of its invertebrates. Utila is known for its healthy black corals and we enjoyed seeing the Bluebell and encrusting tunicates that were abundant on almost every dive site. Corkscrew sea anemones and their resident Pederson cleaner and Red snapping shrimp were common as were the Banded coral shrimp hiding in the crevices. The Brain corals were apparently very healthy and quite large at some sites.
Other dive sites had an abundance of multi-colored lettuce corals and we were also able to photograph some very healthy Elkhorn and Staghorn corals on several dives; an encouraging sight considering these species are now classified as endangered because they have declined 85-98% throughout Florida's reefs and the Caribbean.
A wide variety of colorful vase, tube, finger, and encrusting sponges were also plentiful.
We chose to stay and dive with Utila Lodge based on their association with Whale shark research organizations and the reputation their boat captain has for his keen ability to find Whale sharks whenever and wherever they are present. Captain Willie Waterhouse grew up on the island and knows the waters, the reefs, and the critters like the back of his hand. We're still mystified that he was able to summon 3 Whale sharks on our last day of diving. Although we hoped to get lucky, we were aware that Whale sharks are rarely seen during that time of year. Words can't describe how thrilled we were to have the privilege of swimming with these beautiful creatures against the odds. In addition, twice Captain Willie found us dolphins to dive with and photograph, shy Spinner dolphins and curious Rough-toothed dolphins that were in a playful mood so they cavorted with us in the water for several thrilling minutes.
Because we visited Utila during the off-season, we had the resort and our dive boat to ourselves. We enjoyed the undivided attention of divemaster Stefan the first week who introduced us to the reefs of Utila and helped us find dozens of species to photograph, particularly the nudibranchs that he seemed to be able to find at every site. The second week we dove with divemaster Kate who was also skilled at finding even the tiniest of nudibranchs, and with whom we shared the Whale shark experience. Kate had been on the island for 5 months and this was her first dive with Whale sharks on Utila, a fact that made us feel even luckier for finding them on our last day. The owners and staff at Utila Lodge were extremely welcoming and we felt at home from the first day. Marley, the Lodge's charming manager, gave us a detailed and helpful orientation shortly after we arrived, which included a warning that Queen Ann, bartender and hostess, has a wicked sense of humor that may offend those with delicate sensibilities. Unfortunately, diving all day and reviewing photographs and identifying species at night didn't leave us with much time to see how delicate our sensibilities actually were, we found her absolutely charming and utterly hilarious.
We would recommend Utila Lodge for its atmosphere and convenience. You literally walk out of your room and onto the boat. The entire lodge is built right over the water so surface intervals include sitting on the dock watching the resident tarpon and barracuda trying to feed on large schools of sardines that inhabit the docks, or looking out for Spotted eagle rays and large French angelfish. Or, if you're as diehard marine life lovers as we are, you don your gear and hop off the dock for shallow dives. Although the water was fairly silty, we enjoyed swimming through the school of sardines and watching two Bulldozer shrimp clean house for themselves and their Sailfin blenny watchdog. We were also delighted to find small Yellow stingrays in the seagrass beds as well as Giant hermit crabs inhabiting abandoned conch shells.
If you prefer consistently good visibility, you may want to consider visiting Utila between December-April, which also happens to be “peak” Whale shark season. Even if you don't encounter a Whale shark, Utila has a lot to offer and MarineBio.org hopes to visit again in the future.
OceanFootage.com is a comprehensive collection of some of the very best underwater videography from around the world. Leading cinematographers from across the globe show off their work which visitors can easily view and purchase online. Each species on MarineBio.org is now linked directly to the footage that's available for that species on their site in the droplist titled "Web (video/audio/images +)." For those in broadcasting, movie-making or research requiring video footage, we highly recommend their videos which you can purchase online for a very reasonable prices. They can also set up custom shoots for your projects as well as research footage for specific behaviors, etc. that you might need.
TONMO.com, founded in May of 2000, is "committed to being the best resource available for all things cephalopod, in terms of both community and content." Their forums have over 3,300 members and 58,000 posts, if you find cephalopods fascinating, we also highly recommend visiting TONMO.com.
The DaisyHill Cuttlefarm is a site by a guy that raises and breeds captive cuttlefishes and has some of the greatest movies of cuttlefish behavior online we've seen to date. If you visit and watch only one movie, make sure it's the "Imperial March of the 4 month old cuttles." Enjoy!
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