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FALL 2014
P
hotogenic coral reefs and majestic kelp
forests deservedly garner much of the dive
industry’s interest: They are beautiful,
and they significantly contribute to marine
diversity. Unfortunately, linked habitats such
as sand and rubble slopes, seagrass beds, mangroves,
rusting shipwrecks, piers and docks are habitually
overlooked because they are perceived to lack traditional
aesthetic value. As a result, many people do not fully
appreciate these habitats’ ecological importance.
Piers and docks in particular act as artificial reefs,
harboring an abundance of shallow-water fish. While
not intentionally designed to attract marine life,
these partially underwater structures often serve as
oases for both common and extraordinary organisms
in locations that may otherwise amount to aquatic
deserts. Even though the diversity of life under piers
may seem to be relatively sparse when compared with
healthy Pacific coral reefs, the sheer variety of animals,
plants and microorganisms drawn to these man-made
formations can be vast and the associated food web
exceedingly complex.
Throughout the islands of the western Pacific,
thousands of piers and docks have been built in a
variety of marine environments. Those put in place
along deep channels are swept by nutrient-rich waters,
which deposit prolific filter-feeding marine growth
on their vertical structures. Coralline algae, sponges,
hydroids, tunicates and brilliant Dendronephthya
soft corals develop in ever-changing menageries and
bouquets that proffer limitless micro-habitats for
additional invertebrates and small, planktivorous fishes.
Other piers and docks are built in protected,
current-free bays where large mazes of forested islands,
limestone islets, thick mangroves and narrow channels
serve as nurseries, reproductive sites and feeding
grounds for thousands of marine species. Although
the region may include plenty of thriving underwater
habitats — such as fringing reefs, flooded forests,
marine lakes and submerged seagrass meadows — piers
and docks offer unique characteristics such as dark
recesses sheltered from direct sunlight and stationary
vertical substrates that act as steadfast territories for
both sessile invertebrates and hungry fish.
Drifting down among the dim pilings under just
about any Pacific pier that has been in the sea for more
than a few weeks, divers will quickly see that marine
life can reach robust levels here. Sunlight sparkles
along the edges of the terrestrial platforms above
and peeks through wooden slats, creating striking
light beams that waver across the sand and rubble
bottom. Despite the diversity of the western Pacific
region in terms of colorful, diurnal reef species, most
pier-dwellers prefer muted, gloomy confines where
camouflage is vital to survival. Deep shadows cast by
pilings, dock floats and wooden pier floors provide
hiding spots for intricately veiled critters of all shapes,
sizes and behaviors.
On the bottom, ignoring bubble-blowing divers,
there often live at least a few well-fed scorpionfish,
spiny devilfish or stonefish whose grumpy-looking
countenances blend into the mounds of living rock
and debris. These classic ambush assassins have
delineated invisible territories, much like trolls hiding
under bridges in sinister fairy tales. Venomous, lie-
in-wait predators barely have to move to feed on
large numbers of unsuspecting cardinalfish, damsels,
blennies or gobies that hover on or just above the
nutrient-filled silt. Underneath some docks it is
possible to find the same stonefish in the exact same
spot for weeks at a time. Why move a muscle if food
swims right in front of your mouth?
Not far away from the ambush predators, pairs of
banded pipefish may poke their slender snouts out
from rocky crevices to feast on zooplankton, while a
juvenile crocodilefish, perfectly mimicking a drowned
THE CURIOUS LIFE BENEATH
PIERS AND DOCKS
T E X T A N D P H O T O S B Y E T H A N D A N I E L S
LIFE AQUATIC
