Ocean Health
The world’s oceans are under siege from pollution, overfishing, and other man-made problems all at once, and their health is declining much faster than originally thought. Troubles from global warming, dead zones from farm run-off, an increase in acidity from too much carbon dioxide, habitat destruction, melting sea ice, along with overfishing are worse when they combine with each other all at once.
At an international meeting of marine scientists was designed to consider the cumulative impact of multiple stressors on the ocean. The 27 participants from 18 organizations in 6 countries produced a grave assessment of current threats: that the world’s ocean is at high risk of entering a phase of extinction of marine species unprecedented in human history.
Case Study 1 In Brief: Most, if not all, of the five global mass extinctions in Earth’s history carry the fingerprints of the main symptoms of global carbon perturbations (global warming, ocean acidification and anoxia or lack of oxygen). It is these three factors which are present in the ocean today. In fact, the current carbon perturbation is unprecedented in the Earth’s history because of the high rate and speed of change. Acidification is occurring faster than in the past 55 million years, and with the added man-made stressors of overfishing and pollution, undermining ocean resilience.
Case Study 2 In Brief: What the multi-disciplinary approach of the IPSO workshop made clear for the first time was the multiple threats reefs are facing, that are now acting together to have a greater impact than if they were occurring on their own. This suggests that existing scientific projections of how coral reefs will respond to global warming have been highly conservative and must now be modified.
Case Study 3 In Brief: Continued releases and slow breakdown rates mean that legacy chemical pollution remains a major concern. However, concerns have been raised recently over a wide range of novel chemicals now being found in marine ecosystems or suspected to be harmful to marine life. Some of these chemicals have been located recently in the Canadian Arctic seas, and some are known to be endocrine disrupters or can damage immune systems. Marine litter and plastics are also of major concern, and there is evidence that certain plastics can transport other harmful chemicals in the marine environment.
Case Study 4 In Brief: Scientists agreed that overfishing is exerting an intolerable pressure on ecosystems already under attack by the effects of acidification and warming, and other largely man-made ocean problems. A recent study showed that 63% of the assessed fish stocks worldwide are over-exploited or depleted and over half of them require further reduction of fishing, in order to recover.
Some of the changes affecting the world’s seas – all of which have been warned about individually in the past – are happening faster than the worst case scenarios that were predicted just a few years ago.
Protecting Coral Species From Extinction
Coral reefs around the world are facing extinction due to overfishing, pollution, and the overarching threats of global warming and ocean acidification. Corals in U.S. waters ranging from Florida and Hawaii to American territories in the Caribbean and Pacific, have all declined by more than 30 percent over a 30-year period. The U.S. government pledged to determine by April 2012, whether Endangered Species Act protections are needed for 83 species of coral.
Nine corals in Hawaii waters being considered for endangered species protection are: Fuzzy Table Coral (Acropora paniculata), Irregular Rice Coral or Hawaiian Reef Coral (Montipora dilatata), Blue Rice Coral (Montipora flabellata), Sandpaper Rice Coral, Spreading Coral or Ringed Rice Coral (Montipora patula), (Leptoseris incrustans), (Porites pukoensis), Agassiz’s Coral (Cyphastrea agassizi), Ocellated Coral (Cyphastrea ocellina), and Stellar Coral (Psammocora stellata).
Blue rice coral (Montipora flabellata), only found in Hawaii, blue rice coral is uncommon and thrives in shallow reefs pounded by waves. Although this coral is usually flat and sheetlike, on one reef in Molokai it grows branches with an opening at the tip that provides a home to small shrimp. Blue rice coral is vulnerable to bleaching, habitat degradation, and disease.
Hawaiian reef coral (Montipora dilatata) remains in fewer than five locations. It has the unfortunate trait of being among the first corals to bleach during increased water temperatures, and the slowest to recover. It has experienced significant climate-related population fluctuations over the last 20 years, and its small distribution makes it extremely vulnerable to extinction.
Scientists warn that by mid-century, coral reefs are likely to be the first worldwide ecosystem to collapse due to carbon dioxide pollution, which causes both global warming and ocean acidification. Warm water temperatures in 2010 marked the second-most deadly year on record for corals due to bleaching – a process by which they expel the colorful algae needed for their survival. Many corals die or succumb to disease after bleaching. An additional threat to coral reefs is ocean acidification, caused by the ocean’s absorption of CO2. The agreement is an important step toward legal protections for some of the most vulnerable coral reefs.
Hawaiian Wildlife and Spinner Dolphin Echolocation
Spinner Dolphin use clicks, whistles, and pulsed sounds to echolocate and communicate. Echolocation enable Spinner Dolphins (Stenella longirostris) to track objects in dark water, and to see much further than their eyes will allow. Dolphins bounce sounds off objects and then interpret the returning echo to get an acoustic picture of its surroundings. Their complex array of whistle sounds also allow dolphins to talk to one another. Spinners can identify themselves with sounds they make by trailing bubbles from their blowholes – sounds called signature whistles.
The time lapse between the dolphin emitting the signal and receiving the echo indicates the distance to the object being echolocated, and also the target’s density. By determining the target’s density, dolphins are able to recognize particular species, even in the total darkness of the deep ocean. Researchers discovered that dolphins reduce the volume of the echolocation pulses they emit as they approach the object they are echolocating. The dolphins first use echolocation to check the distance to the object, then adjust their volume and use echolocation to determine the object’s size (the more waves that are reflected back indicates a bigger object). The advanced capabilities of dolphins using echolocation may also allow dolphins to be able to tell if a human is in distress, since there have been numerous reports of dolphins saving drowning people.
Spinner Dolphins also communicate by slapping the water with various parts of their body. For instance, when the pod is emerging from a rest period, they thrust their beak above the surface in what is called a nose-out. Impending danger or a dive is indicated by tail slaps. Head slaps, side slaps, and back slaps most frequently indicates the pod is accelerating. Most spectacular, are the spins themselves. Many animals spin repeatedly, with each spin tending to get smaller and smaller, finishing with an emphatic side slap. Spinner Dolphins (Nai’a in Hawaiian) maximize their splash by twisting around to land in a belly-flop, or back-flop. Spins are most frequently performed while the school is spread out across the water. A spinning dolphin may be signaling to the others direction and speed of travel.
Hawaiian Wildlife and Spinner Dolphins
Spinner Dolphins (Stenella longirostris) are found in off-shore tropical waters around the world, and famous for their acrobatic displays where they spin as they leap through the air. Individuals have been seen completing up to a dozen spinning jumps in quick succession. Spinners also leap high up out of the water, doing a couple of flips in the air while spinning at the same time. In Hawaii they are known as Nai‘a, and are playful, intelligent, perceptive, curious, and often quite friendly.
Spinner Dolphins are dark gray, with darker patches in the tail, back, and throat, and have a lighter belly. Their beaks are distinctively long and thin, with a dark tip, and lined with 180 or more delicate interlocking conical teeth. Adults vary in length from 5 to 7 feet, weigh from 110 to 170 pounds, and live to about 20 years of age.
Spinner dolphins travel in pods, sometimes numbering in the hundreds. Researchers believe that the energetic flips and spins done by spinner dolphins may act as geographical markers for the pod, as well as to let other dolphins know their location. Dolphins often let out a loud sound below the surface right before they leap out and spin.
They hunt mostly at night and eat fish, jellyfish, krill, squid, shell-less snails, as well as copepods. Spinners form small subgroups spread out across miles of water and coordinate their activities through echolocation of sound and spinning. By dawn, the spinners regroup and find shelter during the day near shore, often swimming in large, slow circles. They may alternate brain halves while “sleeping,” allowing one side of the brain to rest while the other side stays active.
Green Sea Turtle and Plastic
Green Sea Turtles (Chelonia mydas) have spent the past 100 million years roaming seas, but are now the poster animal for the impact of plastic pollution on endangered species. A new study from researchers indicates that global sea turtle populations are mistakenly ingesting fatal quantities of plastic debris.
The report firmly lays the blame on so-called “disposable” plastics – beer cups, water bottles and caps, grocery bags, plastic utensils – intended to be used just once and thrown away. While these plastics are cheap and convenient, they are also durable and buoyant-making for a potent and deadly combination in the water. Though only 0.2-0.3% of all plastic ends up in the ocean, last year the world threw away 7 billion pounds of PVC, recycling just one quarter of one percent.
Though plastics like these do break down from exposure to sunlight and other elements, the molecules of plastic never fully biodegrade… they just break into smaller and smaller pieces, but never completely disappear. Eventually, many of these small particles get blown or washed into tributaries that feed rivers which flow to the ocean. Here they swirl in the eddying currents forming a sort of plastic soup where they float virtually forever. Persistence of plastic debris is poignantly illustrated in the account of plastic swallowed by an albatross that had originated from a plane shot down 60 years ago 6,000 miles away. The photo above shows plastic remnants found in the stomach of one young sea turtle.
Hawaiian Wildlife and Spinner Dolphins 4
Once a week a cruise ship visits Rangiroa. Expertly using the pressure wave off the bow, the dolphins get the effortless ride of a lifetime. . . surfing sideways and even upside-down in the flow. . .
At day’s end, as the bottlenose and their adopted spinner surf the waves, a large school of spinner dolphins further offshore makes haste for their feeding grounds. . . Now all the collective energy of the school comes together as the dolphins approach the most thrilling and dangerous part of their lives.
Scientists have likened the dash to the deep — and all its accompanying aerial displays — as akin to a football team psyching itself before a game. This communal pep rally serves yet again to synchronize the dolphins’ intentions, and perhaps to overcome their fears. For as night falls, a change takes place in the deep water far below.
A community of marine life, known as the deep scattering layer — which spends the daylight hours at depths of up to 3,000 feet now begins to migrate upward. As these riches come within reach, many surface dwellers — including the spinner dolphins — begin to hunt. Small subgroups spread out across the sea.
Despite being separated by several miles of water, the school still coordinates its activities through sound — -and through spinning — which reaches an explosive crescendo in the darkness of night . . . Time after time, the dolphins dive . . . down into the utter darkness at 800 feet, or more.
Schools of squid rise with the deep scattering layer. Jet-propelled, they are among the most elusive of prey.
Yet dolphins of many kinds are adept at catching them. For all the spinners’ skill and agility in this eerie world, they are wary of predators. Many sharks live in the deep scattering layer . . .
Using their echolocation, the spinners scan the darkness. . . then using their whistles, they call members of the school back together. and unite for their defense . . . And so most nights, the collective defenses of the dolphin school protect each member from harm. By dawn, the spinners regroup. Well-fed, they move once again towards the shelter of the islands.
Millions of years of natural selection have made spinner dolphins supremely adapted to the paradoxical worlds they inhabit . . one in the darkness of the abyss . . the other in the sunlit shallows. But nothing in their evolutionary past has prepared these dolphins for the onslaughts of the modern age. In the open sea, spinner dolphins and spotted dolphins frequently swim above large schools of yellowfin tuna. Fishermen in the eastern tropical pacific use dolphins to locate the tuna. . . Then set their nets around the dolphins.
O/C Marten:
Setting nets on dolphins to catch tuna kills them in large numbers. There’s no way to avoid that. And really what the public ought to understand is that the problem is not solved. Dr. Ken Marten was an official observer aboard u.s. tuna boats for two years. His job was to count and report the number of dolphins killed.
V/O Marten:
The mother boat launches 4 to 6 speedboats which chase the dolphins for an hour or more at high speed until the dolphins are exhausted. The mother boat approaches and sets the long purse seine net around the dolphins.
Any place the net is still open, the speedboats are sent and now they have a new function — to drop bombs into the water, that explode, and prevent the dolphins from escaping out of the net. And the rationale behind that is that if the dolphins ever escape out of the net, the tuna escape with them.
The nature of such a huge net around dolphins for such a long period of time, is that dolphins can get caught in folds of the net and drown. And it can happen to all of the dolphins in the net. And the number of dolphins in the net may be 3 or 4,000. These aggregations of spinner and spotted dolphins in the deep eastern tropical pacific are almost like little cities of dolphins. And the entire city can be wiped out.
The spinners’ brilliant defensive systems. . . group loyalty . . . sonar . . . speed and agility . . offer them no protection here — and may even work against their survival in the chaos of the nets.
Many of the dolphins who do escape may die soon afterward . . . as they are now completely deafened by the bomb explosions underwater. Tragically for a dolphin being deaf is equivalent to being blind.
Marten:
I can state this on my own experience, because when the tuna fishermen used to throw the bombs at me, as an observer, to keep me from reporting large kills, those bombs made me deaf for about a day. Nor do the “dolphin-safe” labels appearing on some cans of tuna offer absolute guarantees that no dolphins were killed . . . Meanwhile, the effect of tuna fishing on dolphins has been catastrophic. Today, more than 60 percent of the population of spinner dolphins in the Eastern tropical pacific has been wiped out in the tuna nets.
This morning, after a successful night of hunting, the spinner dolphins of Kealakekua Bay are returning to shore. Mornings are a time of celebration — as the members of the school meet, and play together. Youngsters practice their lessons. Little by little, the warm, clear waters entice them to rest . . . the dolphins draw closer. Together they rise and fall from the surface . . . until each spinner slips into sleep, safe inside a cocoon of friends.
In the 30 years that spinner dolphins have been studied, much has been Deciphered of their lives in the wild. Yet most of their world remains — and may always remain — completely mysterious. They thrive in what is essentially a different universe . . and yet, we feel close to them.
Perhaps the attraction lies in a sense of kindred spirit . . .
For although we understand something now of the complex and serious business of their lives. . . we can also feel their unique and joyful energy. . . that moment of flight . . . that instant when the burdens of life are cast away.
