Feeding the Crustaceans

While we no longer own dogs or board horses, we are raising crustaceans.  These pill bugs reside in our compost bin, where hordes of their young mingle with the adults.

Our duty is limited to filling the bin with vegetable, fruit and yard waste.  This weekend, hosting family members for the Holiday, we produced a large amount of watermelon rind, a clear favorite of the pill bugs.  Drawn to the hot, humid confines of the bin, these crustaceans are, in turn, agents of compost production.

Unlike pets that require expensive nutrition, vet care and occasional boarding, wild creatures are a bargain.  This is especially true of invertebrates that engage in pollination or recycling; then again, they do not offer companionship or unconditional love. 

To Margaret Bay

Ketchikan spreads along the southwest coast of Revillagigedo Island but most of the island is uninhabited.  Today, we enjoyed a boat ride to Margaret Bay, one of several that indent the northwest coast of Revillagigedo.

The purpose was to set a couple of crab traps in Traitor's Cove and to take a hike to a bear-watching site in the Margaret Creek Valley; the latter is managed by the National Forest Service.  A two-mile, roundtrip hike takes visitors to an overlook blind above the creek, where black bear fish for spawning salmon.  During our stay, we were fortunate to observe two young bears, fishing at a waterfall along the creek.

The trapping effort produced one Dungeness crab and we stopped to check several shrimp traps on our way back to Ketchikan; those traps were highly productive though an octopus and several large starfish had eaten some of the catch.  Beyond these highlights, the trip provided spectacular views of the waterways, mountainous islands and rugged peninsulas north of Ketchikan; our thanks to Steve and Gary for the seven-hour tour.

Inspecting the Dead

Wanting to get closer to the red tide destruction, my wife and I visited Whitney Beach this morning.  Stretching along the northwest edge of Longboat Key, it is both the most scenic stretch of sand and (in my opinion) the best birding location on this barrier island.  As expected, the beach was littered with dead fish, eels, rays and horseshoe crabs and the variety of birds was far below normal.

Wandering among the dead, we endured the nauseating stench of rotting sea life.  While a couple of yellow-crowned night herons and a dozen shorebirds (black-bellied plovers and ruddy turnstones) scoured the beach, they stayed clear of the victims; brown pelicans and large flocks of laughing gulls passed overhead or lounged far offshore.  Except for a lone hunter with his metal detector, we were the only humans on that popular beach.

Though the algal counts have waxed and waned along Florida's Southwest Coast, the red tide is expected to persist until a tropical storm or cool autumn weather invades the region.  There is trouble in paradise and, this morning, we bore witness to its wrath. 

A Seething Mass of Invertebrates

In the wake of our tropical heat and heavy rains, our compost bin was a seething mass of invertebrates when I dropped off the veggie and fruit scraps last evening.  Pill bugs (rollie pollies) of various species dominated the scene, joined by beetles, harvestmen (daddy longlegs), fruit flies, worms and an assortment of larvae.  Of course, the predators (primarily spiders) were there as well.

The nightmarish scene, backed by a pungent mass of rotting vegetation was not for the faint-of-heart but was rewarding for one (i.e. myself) who built the bin two and a half years ago.  Since its completion, we have thrown tons of yard and kitchen waste into that simple contraption and have yet to remove any compost.  The efficiency of the scavengers and recyclers is certainly amazing, joined of course by microscopic bacteria and fungi.

Indeed, a compost bin offers a contained view of nature's less appreciated creatures at work.  Their vital activity is multiplied a billion-fold across our neighborhood but is rarely observed and generally unappreciated.  Anyone who wants a close-up look at their handiwork should buy or construct a compost bin; it will reduce your contribution to landfills, discourage your use of pesticides and augment your devotion to natural recycling.

Our Crustacean Farm

Three months ago, we established a compost pile in our Columbia, Missouri, yard (see Building a Compost Bin).  Since that time, the grass clippings, dead leaves, sawdust and kitchen leftovers (fruits, eggshells and vegetables) have decayed into a darkening mound of maturing compost, fueled by the heat and humidity of a Midwestern summer.

Feasting on the organic matter and facilitating the process of decomposition is an army of insects, including ants, fruit flies and various beetles; of course, earthworms are doing their part from within the pile.  But the most numerous and conspicuous residents of the compost bin are pill bugs, those prolific Backyard Crustaceans known to children as rollie pollies.  Relying on gills for respiration and consuming a diet of carrion and rotting vegetation, they thrive in the warm, moist confines of the bin; indeed, peering into the structure, a novice might assume that it was designed to raise pill bugs.

Unfortunately, there is not a lucrative market for these ubiquitous crustaceans; in fact, the internet is loaded with advice on how to keep them out of your garden and basement.  While they may do limited damage to ground-spreading plants such as strawberries or melons, pill bugs are, for the most part, beneficial creatures, recycling organic material and enriching the soil.  They are certainly welcome in the compost bin!

Joan M. Durante Park

Acquired by the town of Longboat Key in the 1980s, this 32 acre park once harbored a small community.  The cabins have since been removed, native vegetation was preserved and the mangrove ecosystem has been restored.  Visitors can now wander along a network of shell fragment trails and boardwalks to explore both the mangroves and a coastal hammock forest of red cedar, cabbage palm, saw palmetto and seagrape.  Along the way, bridges cross tidal creeks (vital nurseries for marine fish) and decks provide sweeping views of Sarasota Bay.

Among the wide variety of wildlife that inhabit Joan M. Durante Park are ospreys, wading birds, belted kingfishers, anhingas, gray kingbirds, red-bellied woodpeckers, palm warblers (winter), mangrove crabs and fiddler crabs.  From the bayside decks, one can observe brown and American white pelicans, double-crested cormorants, various herons and egrets, wintering red-breasted mergansers and loons and a host of gulls and terns; the visitor can also scan the shallows for starfish, sea urchins, horseshoe crabs and other marine life.

On this cloudy, breezy morning, ospreys were especially noisy and abundant, calling from the top of trees or fishing over the windswept bay.  Little blue herons and white ibis hunted along the tidal creeks, cormorants and brown pelicans cruised above the choppy bay, royal terns dove for their breakfast and a lone box turtle dozed at the edge of a trail.  As usual, we enjoyed a pleasant stroll through a beautiful and fascinating ecosystem.  

Backyard Crustaceans

Mention crustaceans and most of us think of aquatic creatures such as lobsters, crabs, shrimp and crayfish. But, unless you reside in an arid environment, you have many crustaceans in your own backyard.

Pill bugs, known affectionately as rollie pollies, have segmented bodies like their aquatic cousins but have the unique ability to curl into a tight sphere when threatened. Since they, like other crustaceans, breathe through gills, they must remain in moist areas and are typically found beneath logs, rocks, leaf litter or man-made structures; they might also be encounterd in the moist recesses of your garage or basement. Pill bugs feed on a variety of organic matter, such as rotting vegetation and carrion, and thus play an important role in recycling nutrients; while they also feed on living plants, they are rarely a problem for gardeners.

After mating, the female pill bug produces up to a hundred eggs or more, which are carried in a brood pouch for almost a month. Once these eggs hatch, the tiny offspring, miniature replicas of the adult are on their own; each will molt at least five times before reaching adult size and, unless consumed by birds, toads, spiders or other predators, may inhabit our yard for up to three years.

Ghost Crabs

Residents of sandy beaches, ghost crabs live in burrows that they dig along the seaward edge of the dune line. These burrows are up to four feet deep and provide a cool, wet retreat where the crabs escape predators and keep their gills moist and functional. Though they are most active from dusk to dawn, scouring the beach for food and bathing their gills in the surf, ghost crabs are often encountered during the day and are easily identified by their pale color and prominent, dark eyes; the latter, which sit atop stalks, give these crustaceans a comical, alien appearance.

Ghost crabs were abundant on Longboat Key this past week; both immature and adult crabs scurried across the beach throughout the day, diving into their burrows or out into the water as walkers approached. They feed on a wide variety of plant and animal life, including seaweed, carrion, sand fleas, mole crabs, stranded fish and sea turtle hatchlings; their taste for the latter has led to their persecution in some turtle recovery areas.

Named for their pale coloration, nocturnal activity and rapid disappearance into burrows, ghost crabs are a food source for night herons, great blue herons, raccoons and gulls. They are also threatened by beach erosion and, ironically, often succumb to artificial beach restoration efforts. For now, their welfare seems assured on Longboat Key!

Prairie Crayfish

Most of us associate crayfish with southern bayous, shallow rivers and rocky creeks; some of us also recall the blind, albino crayfish that inhabit the streams and pools of caves. But there are also a large number of terrestrial species, of which the prairie crayfish is one of the more common.

Favoring wet meadows and floodplain grasslands, prairie crayfish dig burrows to access their cool, moist habitat, often leaving chimneys of mud around the entrance. Deep enough to reach the water table, these burrows may be far from surface water and often extend to depths of six feet. The crayfish emerge from the burrows at night (or during periods of cloudy, humid weather), wandering the grassland to find mates or food. In spring and fall, large numbers may be encountered on rainy mornings as they cross trails or country roads.

Terrestrial crayfish can be a nuisance in some crop or tree farm regions but otherwise play an important role in the wetland-prairie ecosystem. Their digging aerates and mixes the soil and their burrows provide wintering sites for amphibians, lizards and snakes. Showing little appreciation, these same creatures feed on the crayfish, as do herons, raccoons, otters, mink, fox and humans. Those that survive predation mate in March and the female crayfish carries fertilized eggs on her abdomen for two months; once hatched, the tiny youngsters remain attached to dear old mom through their first two molts before dropping off to fend for themselves.

Blue Whales and Krill

Blue whales, the largest animals to ever inhabit this planet, reach up to 100 feet in length and weigh up to 190 tons; females and those in the Southern Hemisphere tend to be the largest. Numbering 350,000 before the age of modern whaling ships, 99% of their population was decimated during the early-mid 1900s. Slowly recovering since the 1970s, blue whales now number somewhere in the range of 8-15,000 individuals, 2/3 of which live in the Southern Hemisphere.

Protected from human hunting, these marine giants now face a dwindling population of krill, their primary food source. Krill are small, shrimp-like crustaceans that live in the open ocean waters, feeding on phytoplankton and often massing in huge schools, containing billions of individuals. In fact, their vast numbers make krill the most abundant (by mass) animal on the planet; 85 species inhabit the Earth's oceans. Nevertheless, krill populations are diminishing, having dropped by 80% over the past 30 years in some parts of the Antarctic. The cause for their demise remains uncertain but warming sea temperatures and a reduction in sea ice are thought to play a role (krill feed on algae that accumulate on the underside of the ice shelfs). In recent decades, man has also been harvesting krill for use as aquaculture feed and for the production of krill oil, a popular health food item. Should krill populatins continue to decline, the welfare of all baleen whales and many species of penguin, seal, fish and sea birds will be threatened.

To support their massive frame, blue whales consume up to 4 tons of krill each day; much of this consumption occurs in the cold polar seas during the summer months, when the perpetual daylight fosters extensive phytoplankton blooms (and thus phenomenal runs of krill). Moving on to Temperate and Tropical seas to give birth and to breed during the winter months, blue whales feast on other krill populations along the way. Impregnated females carry their calf until the next winter and will then nurse it for another 8 months; mature females generally give birth every 2-3 years. Despite the many threats to their welfare, blue whales may live 80 years or more.