How bad are the oceans?

Posted on April 19th, 2015 in Climage Change,ecology,Environment by Robert Miller
Indonesian surfer Dede Surinaya catches a wave in a remote but garbage-covered bay on Java, Indonesia, the world’s most populated island ‘Water and air, the two essential fluids on which all life depends, have become global garbage cans.’ Jacques-Yves Cousteau Photograph: Zak Noyle

Indonesian surfer Dede Surinaya catches a wave in a remote but garbage-covered bay on Java, Indonesia, the world’s most populated island
‘Water and air, the two essential fluids on which all life depends, have become global garbage cans.’ Jacques-Yves Cousteau
Photograph: Zak Noyle

If you are like me seeing this image, a surfer in “the pipe”, catching a wave full of garbage is as a repulsive an image as one might imagine—-but it does say a lot about how we are treating our oceans—-like  a vast, un-managed  garbage dump available to all who live near the oceans, as well as some who don’t: one way or another we are all guilty. But this scene is only the beginning of the problems our oceans face world-wide.

When I served in the Navy beginning in 1969, I was stationed in Pensacola, Florida on the gulf coast. It was there that I discovered one of my favorite eating fish, the Red Snapper, which at that time was in great abundance: Red Snapper swam in schools you could see around the docks close to the shore in Escambia Bay, Pensacola’s gateway to the gulf. Local fishing boats took passengers out into the bay to indulge in what was usually a plentiful catch. People could always count on a dinner of Red Snapper, just by dropping a fishing line in the water. Along the gulf coast, living off the ocean was not just a myth, but a reality enjoyed by all who wanted to participate, young, old, wealthy or poor: at the time it seemed as if there was fish aplenty, that the stores could never be depleted. But that all changed within my lifetime. I had a chance to visit that area a few years ago and was shocked to learn how things had changed: Red Snapper fishing was not so easy anymore. Fishing boats have to go out 50 to 75 miles into the gulf just to see and fish for Red Snapper: very often they didn’t catch any. This has all taken place within a generation.

As fish stocks are depleted, they are replaced by jelly fish. There are already depleted fish schools that used to be plentiful, including the cod fishery off of Newfoundland and the blue tuna fishery world wide. It is a shocking to read world sailor Ivan Macfaydyen’s account of the difference when making the same global sailing trip between Melbourne and Osaka,  Japan just ten years ago compared to his most recent voyage over the same route. On the trip ten years ago, he comments “there was not one of the 28 days on that portion of the trip when we didn’t catch a good-sized fish to cook up and eat with some rice.” He points out that, in his most recent sailing adventure, he found a dead ocean—-no birds, no fish: during the entire journey he netted just two fish. The Major life he saw was a whale with a tumor on its head.

But our oceans are far worse than what this image conveys.  It’s what we are dissolving in the ocean that threatens the oceanic environment far more than the visible garbage, as repulsive at the image above might be. The oceans are a sink for the increasing levels of carbon dioxide in the air which, when dissolved in the ocean, forms carbonic acid, leading to acidification and a loss of coral formation. Many experts are predicting that coral reefs will be gone within the time frame of a single generation.

We have created large dead zones in our oceans, as excess fertilizer, carried off the land by rain and carried by streams to the ocean.  In the ocean it nourishes a huge growth of algae, and the decaying algae nourish a huge growth of bacteria.  The bacteria suck all the dissolved oxygen out of the water, and the fish die.   This has created huge dead zones in coastal waters and, some suspect, in the deep ocean as well, though that has yet to be confirmed.

Recently the largest dead zone ever recorded invaded the gulf of Mexico and covered 8,500 square miles conveying death to every fish in its wake. Over the past 10 years a number of fish stocks have collapsed. These include the Peruvian anchovy, Alaskan pollack, North Sea cod, South African anchovy, Alaska king crab, and California sardine.

Canada has eliminated cod fishing off Newfoundland because of overfishing. This area used to be one of the world’s richest sources of cod. Overfishing drove cod populations so low, that further fishing would have driven the species to near extinction. Giant trawlers, having nets that reach the bottom have caught the breeding size fish such that reproduction has been largely eliminated.

The most disturbing feature of how we are treating our oceans is that we are destroying our oceans before we understand them. That, combined with the fact that no country assumes responsibility for maintaining ocean quality, means that we are almost helpless as we witness the decline in ocean quality, without the capacity to do anything about it.  Have we reached a point of no return in overpopulation and over fishing?

Plastics are also a major source of ocean pollution. Ocean plastic breaks up into bite-sized pieces, eaten by fish who die from the ingestion. There must be a syndrome for this but I couldn’t find it: Plastic Fish Intoxication?

Mexico City, the 19th most populated city on the planet with 5,974 people per /Km2

Mexico City, the 19th most populated city on the planet with 5,974 people per /Km2

Mexico City is only the 19th most populated city on the planet but this image conveys how city growth has left the city with no room for parks or more natural habitat. When the city experiences temperature inversion smog, birds flying into the smog will very often die before finishing their journey. We are choking off the air we breathe and the oceanic contribution to our food intake. When will we learn to seriously address these problems? We almost don’t know where to begin. One in six jobs in the United States is related to the ocean.

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An enchanting nature story

Posted on April 26th, 2014 in ecology,Nature by Robert Miller

NYT drawing by Eric Nyquist

Last week, the New York Times, in its op-ed section, ran a charming story written by Richard Conniff (who also authored “The Species Seekers: Heroes, Fools, and the Mad Pursuit of Life on Earth”). The story, entitled “An Evolutionary Family Drama,” is about landlocked and anadromous alewive fish (anadromous means born in fresh water, spend their lives in the sea and then move from a marine environment to fresh water to spawn, like salmon). Alewive fish are commonly known as river herring. The drama takes place on Roger’s lake which is located in Connecticut; it was the first lake to be dammed along the Millbrook river, which flows into Long Island Sound and then to the sea. When the dam was first constructed in 1672 it immediately divided the alewive population into landlocked and anadromous subtypes. The anadromous fish continued to spawn in below the dam, while those above the dam in Roger’s lake were robbed of the ability to respond to nature’s call for an annual migration, but learned to breed and propagate the species in Roger’s lake.  Now, the dam has been modified to include fish ladders so that the anadromous alewives can reach the lake to fulfill their inborn biological demands to spawn in fresh water and get as high in the river system as they can. Thus a new experiment has been launched, which will be played out this year, with the arrival of anadromous alewives to mix with their landlocked mates who they haven’t seen for 342 years. During the long course of their separation, sea dwelling alewives have maintained their size of about a foot in length, while the landlocked alewives are only about 1/3 the size of their sea-dwelling counterparts. You can imagine the many fascinating issues that will be addressed this year: will the two groups interbreed and if so will the young regain/retain their biological drive to migrate back and forth between the sea and freshwater? We know that fish have a way of growing to a size that fits the environment. Put certain species of fish into a larger aquarium for example and they grow larger. Based on that simple model, one would expect that if the alewives revert to a sea life, they will emerge as larger fish. But there is already a problem about interbreeding: From the article in the NYT “So what will happen when the two forms of alewife come together? Size may not matter for mating, since alewives don’t practice internal fertilization. Instead, they broadcast sperm and eggs into the water simultaneously. But the anadromous alewives begin breeding several weeks ahead of their landlocked cousins. So the two forms may just pass one another with a glance, curious but puzzled.”

Alewives are considered to be a key species. Though small by ocean standards, they are main predators in fresh water and drive the ecosystem of every coastal lake and stream from the Carolinas to Maine though their range for any single river has been stunted by dams. When alewives return to the sea, together with menhaden, Atlantic herring and other forage fish, they serve as the basic food stock for the entire Atlantic fishery, as well as for seabirds, whales, dolphins and other species. The attempt to reduce the barriers for migrating fish to get to places they haven’t been to for decades if not centuries, is an effort to recognize and respond to the ecosystem needs and restore the natural migratory patterns that were here before we put in our dams and diverted the waterways. Roger’s lake is undergoing an experiment, 342 years delayed, that will play out over several years to see what happens to the ecology of river systems once the natural migratory patterns of the alewives are restored. Will all the alewives revert to sea-going types, will the landlocked and sea-dwelling fish adjust their the timing of their breeding learn to interbreed, will the ecosystem of Roger’s lake revert to what is was centuries ago? These are surely fascinating questions and the beginnings of answers to them may be evident in the coming months of the new Roger’s lake.

RFM

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Will the red knot bird survive or become another dodo bird?

Posted on November 29th, 2013 in ecology,Nature by Robert Miller
Red knot birds

red knot birds

Several years ago (2010) I wrote an article entitled “The counter-intuitive interconnectedness of species” in which I explained how the red knot (Claidris canutus rufa) bird makes a remarkable, annual journey from Tierra del Fuego (off the southern tip of South America) to the Canadian Arctic where they nest over the short arctic summer and then return home again in the fall. On the way to its arctic stop, the red knot stops along the East coast to feed on eggs laid by the horseshoe crab (Limulus polyphemus), an ancient, primitive-looking crab, that is indigenous to the shorelines of the East coast. The horseshoe crab has been around for 475 million years, so they have sticking power, despite their seemingly clumsy ways and odd shape. The timing of the red knot arrival coincides with the breeding season of the horseshoe crab who come close to the shore to lay their eggs. The red knot birds have about two weeks to feed on the eggs and build up enough body fat and strength to complete their journey. But the horseshoe crabs are becoming scarce. They not only serve as bait for fisherman in the region, but their blood is used in medicine, as the Limulus amebocyte lysate (LAL) is used as a test to detect bacterial endotoxins, for which it is a highly sensitive, unique detection system. Although medical blood-letting is associated with release of the Limulus, a considerable number of the animals die from this experience. A NYT article on the plight of the red knot bird points out that the population of these birds has plummeted by 70 percent since the 1980s. The United States Fish and Wildlife service has proposed to designate the bird as threatened. If the red knot receives this distinction (we apparently will know by Friday), then the government will develop a plan for the bird’s recovery. If so, this will surely involve additional protections for the horseshoe crab, whose diminished numbers have no doubt contributed to the bird’s decline. If use of horseshoe crabs as bait declines through enforcing new limits, the medical use of the crab’s blood is very likely going to increase, given its importance.

Horseshoe Crab (Limulus polyphemus)

Horseshoe Crab (Limulus polyphemus)

One area where survival improvements could be made is to increase the likelihood that blood letting will be more compatible with crab survival. Some estimates suggest that as many as 20 to 30 percent of the crabs from which blood has been withdrawn do not survive. Since 2004, the demand for horseshoe crab blood has increased by 85 percent.

Given what seems to be a biological event of unique synchronization, biologists worry that global warming mechanisms that may interfere with this dependency (an early spring, such that the birds leave too early, or crabs breed out of sync, the threats of ocean acidity from absorbing carbon dioxide on the life cycle of the crab, changes in the arctic that could effect the breeding grounds of the red knot). One could go on and on with other possibilities. How this interdependency between the horseshoe crab and the red knot got started  is itself a remarkable, but unknown story. If crab shortages continue, will the the red knot be able to find alternative sources of food? Given the huge drop in the red knot population that answer appears to be no.

Another animal impacted by the drop in the horseshoe crab population is the Atlantic loggerhead sea turtle that feed on Limulus: their numbers have been dropping. Harvesting crabs was banned in New Jersey in 2008.

loggerhead sea turtle (from Wikipedia)

The horseshoe crab has played a major role in our understanding of visual physiology; studies of this animal led to one Nobel Prize (1967, awarded to H.K. Hartline, Ragnar Granit and George Wald; Hartline was the Limulus guy).

RFM

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