|Biology of the Seashore|
The course, Biology of the Seashore, is an off-campus course
taught by Floyd Sandford, Professor of Biology at Coe College in
Cedar Rapids, Iowa. The course is taught in January on Dog
Island, Florida. Dog Island is the eastern-most of a chain of
barrier islands located off the northern panhandle of Florida.
Much of the island is being preserved in its natural state
through the efforts of the Nature Conservancy and the Barrier
Island Trust. The island is accessible by ferry from Carrabelle
on the mainland and from small aircraft. Since the course was
first offered in January of 1986 over 120 Coe College students
have visited Dog island, studying the marine organisms located in
the NE corner of the Gulf of Mexico.
The following is a list
compiled by Dr. Sandford and Coe college studies of the animals
of Dog Island.
Photographs: Coe College off-campus course, Biology of the Seashore, taught on Dog Island, Florida during the month of January. Photo's show instructor Floyd Sandford and members of the classes of 1990 and 1991.
Photo 1 (top left): During a field trip to the Gulf Marine Institute in Panacea, FL, instructor Sandford holds up an inflated striped burrfish, Chilomycterus schoepfi, while Coe student Jennifer Lokenwitz looks on in astonishment.
Photo 2 (top right): Coe students Bridget Buschmann and Milli Brown rest on the deck of the Pelican Inn on Dog Island, with some of the litter cleared from the beach at the end of a beach clean-up. Some unusual items were found littering the shore, including tires, tackle boxes, and a stereo radio casette recorder. Plastics and styrofoam pieces were common, along with glass beverage bottles, light bulbs and food jars, and aluminum beverage cans.
Photo 3 (bottom left): Students in the class of 90 along with instructor Sandford identify some of the animals found in a tidal salt marsh at the East end of Dog Island.
Photo 4 (bottom right): Students in the Coe College Biology of the Seashore class of 1990.
SOME COMMON ANIMALS OF DOG ISLAND, FLORIDA
Prepared for students enrolled in the Biology of the Seashore class
(WTR-025) at Coe College
Compiled by Floyd Sandford, Biology Dept., Coe College, Cedar
Rapids, IA. 52402 [This is only a partial listing and includes mainly
those animals likely to be found during January.
This compilation is based on 4 day visits in August of '86 and
'89, two weeks in July '93, one week in June '96, and the months of
January '86,'87, '88, '90, '91, '92 '93, '94, '95, 97, 99, and one week in
I. Phylum PORIFERA [Sponges]
1. Orange Devil's finger - Axinella polycapella
In the past literature the hermit crab sponge has been identified as
Xestospongia halichondriodes or as Suberites compacta. Both
incorrect. The true identity of the sponge, as a sub-population of
Spongosorites suberitoides, was clarified by Sandford and
in 1996 (J. of Natural History) and the species redefined on the basis
of specimens collected in the Dog Island area.
This compact and colorful sponge (green, brown, or orange) grows on
a gastropod shell and lives in association with a hermit crab,
typically either Pagurus impressus or Paguristes hummi.
Common in '92, '96, '99, abundant in '94, less common in '93, uncommon in
II. Phylum CNIDARIA (formerly called the COELENTERATA)
A. Class: Hydrozoa
B. Class: Scyphozoa (true jellyfish; pelagic habitat)
1. Moon jellyfish - Aurelia aurita
C. Class: Anthozoa [anemones and corals]
III. Phylum CTENOPHORA ["comb jellies"]1. Sea pansy - Renilla
1. Sea walnut - Mnemiopsus mccradyi
IV. Phylum PLATYHELMINTHES [flatworms]
V. Phylum NEMERTEA [ribbon worms or proboscis worms]
VI. Phylum BRYOZOA ["moss animals"]
1. Lettuce bryozoan - Thalamoporella
VII. Phylum ANNELIDA [segmented worms]
A Class: Oligochaeta [earthworms]
B. Class: Hirudinea [leeches]
C. Class: Polychaeta
Top1. Clam worm - Nereis
VIII. Phylum MOLLUSCA
A. Class: Amphineura (Polyplacophora) [chitons]
1. Common chiton
B. Class: Scaphopoda [tooth shells]
C. Class: Pelecypoda (Bivalvia) [bivalves]
D. Class: Gastropoda [univalves - snails, whelks, etc.]
1. Keyhole (cayenne) limpet - Diodora cayenensis
E. Class: Cephalopoda
IX. Phylum: ARTHROPODA1. Common octopus [over 200 found dead in bay in '99]
Class: Merostomata - the Horseshoe crab, Limulus polyphemus
A. Barnacles -- e.g. Acorn barnacles (Ivory and striped barnacles) Sea whip barnacle (Balanus galeatus)
B. Decapod (10-legged) crustaceans (shrimp,lobster, crabs etc)
Hermit crabs:1. Peppermint shrimp (a cleaning symbiont)
1. Red flat-clawed (or dimpled) hermit - Pagurus impressusBlue crabs and speckled crabs are swimming crabs w/ flattened bodies and the 5th and last pair of legs flattened and oar-like. During August 14-18 of '89 these crabs were very common in the shallow water off shore on both the bay and Gulf side of Dog Is. Many were "sponge" females carrying eggs.
A giant red hermit crab Petrochirus diogenes was found in
water several yds north of the marsh inlet on the E. end on 1/23/91.
It was in a 5" long lightning whelk shell encrusted with barnacles and
several chitons. Inside its shell were several symbiotic small
porcellanid crabs. P. diogenes was common in January '96
and very common in '99. Nearly all were carrying from one to seven cloak
anemones. On 1/25/96
three were found predated by gulls on the beach near the E end marsh
X. Phylum: ECHINODERMATA
A. Class: Holothuroidea [Sea cucumbers]1. Striped sea cucumber (Thyonella)
B. Class: Asteroidea [Starfish, sandstars]1. Gray sand star or Striped sand star (Luidea clathrata)
On 1/19/88, following heavy surf, the Gulfside beach of Dog Island
was literally covered by gray sand stars and fewer numbers of mottled
sand stars. We found sections of beach with thousands of animals.
Foll. a storm on 1/23/92, accompanied by significant beach erosion,
hundreds of striped sand stars and a few burrowing stars were found
washed up on the Gulf beach by Cannonball Acres.
2. Mottled sand star or Banded Luidea (Luidea alternata)
C. Class: Echinoidea [sea urchins, sand dollars, sea bisquits]1. Purple sea urchin (Arbacia punctulata) (long-spined)
D. Class: Ophiuroidea [brittle stars]XI. Phylum: CHORDATA1. Long leg brittlestar (or Mud brittlestar) [also called burrowing brittlestar as it uses its very long thin arms to burrow in mud or fine sand]
Subphylum: Tunicata (Urochordata)
A. Tunicates [Sea squirts]Subphylum: Vertebrata1. Sandy sea squirt (Molgula)
B. Class: Pisces [marine fish] (this is only a partial list)1. N. sea horse (Hippocampus)
Hundreds of sting rays were sighted in the shallow water around
Dog Is. in August of '89. Many hundreds of cowfish, along with
some seahorses and burrfish were washed ashore, along with piles
of sea grass, during rough surf and a high tide on 1-7-90.
Several dead bonnethead sharks, one 3' long, were found washed up
on the E end Gulf beach in July '96
C. Class: Amphibia (small brown frog found Jan '90; spp. unknown) [frogs can be heard calling from freshwater wetlands near the Pelican Inn on mild evenings]
D. Class: Reptilia1. loggerhead sea turtles nest on Dog Is. in the summer.
E. Class: Aves
On 8/16/89 at 11am F. and S. Sandford sighted two glossy ibis
feeding in the salt marsh on the bay side just W. of the air strip.
At that time Glossy ibis were not currently listed on the Dog. Is.
In early January '91 several students saw an osprey, but it was
not seen again during the month. The osprey nest was located about
60' off the ground in a dead pine tree about 100 yds inland and 300
paces north of the marsh inlet on the East end.
Ea. January that a Coe College biology class has visited Dog Is.
we have found dead or ill common loons. The first to discover and
publicize the abnormally high mortality rate of common loons in
Florida was Laurence Alexander. While a field worker with the Nature
Conservancy he discovered his first dead loon -- on Dog Island -- in
the winter of 1983. Thousands have been found since. Many autopsied
loons autopsied carry very high levels of mercury in their tissues.
The cause of heavy loon mortality in Florida in the loons that winter
in norther Florida is not fully known. In January '91 we found 7 dead
loons washed up on Dog Island. 6 had recently died.
[Reference: J. McIntyre, 1989]
E. Class: Mammalia1. Bottlenose dolphin - Tursiops truncatus. A young dolphin measuring close to 3' long was found dead on a sandbar on the East end near the marsh inlet on 1/25/92 Terrestrial mammals (other than domestic dogs and cats):
Deer and fox have reportedly been sighted, but are likely not
permanent island residents. In Jan of '87 we found a very large dead
beaver on the beach on the bay side facing St. George Sound,
presumably washed up there from the mainland. On 1-10-90 we found a
decomposed wild pig at high tide mark on the East end, likely washed
there from the mainland.
There is a possibility that a small population of the endangered
St. Andrew beach mouse, Peromyscus polionotus peninsularis may
on Dog Island, likely on the West end.
PLANTS OF DOG ISLAND AND OTHER INFORMATION
Students in the Biology of the Seahore class do not spend much
time identifying the plants of Dog Island, but some general
information is given below.
Off-shore of Dog Island in shallow water are sea grass beds.
They form vast meadows that are important as nursery grounds for small
fish and many invertebrates. Broken-off pieces of some of the sea
grass plants, such as needle-like manatee grass and flattened blades
of turtle grass are often washed ashore. Sea weeds, floating pelagic
plants without true roots, are often washed ashore. One of these is
Gulfweed (Sargassum). There are several different types -- all are
brown and have air floats or bladders. Great floating masses often
wash ashore. Search these masses for animals that might be clinging
to the plant.
Spartina, marsh cordgrass, is a char. species found in the
marshes on the E. end of the island. The other common plant of the
salt marsh habitat is Juncus, commonly called "needle rush".
usually higher up in the marsh and less regularly covered by the tides
than Spartina. Juncus grass sticks up likes hundreds of long sharp
needles, often making it painful to walk through a marsh.
Sea oats is a beach grass of the fore dunes and older dunes. Its
extensive root system, like those of other dune grasses, helps to
stabilize the dunes and reduce wind erosion.
Almost all the pine trees on the island are Slash pine, but you
may find a few Longleaf pines. The short wind-sculpted pines on the
trail to the W. end of the island before you reach Cannonball flats
are a very old relict population of Sand pines. This area is one of
the oldest and least-disturbed parts of the island. Other plants
include Coastal live oak, beach rosemary, and Reindeer lichen as a
common groundcover in the pine forests.
Note: There are scorpions on Dog Is. and they are active in
January. Please be careful if you decide to turn over boards, logs,
etc. when in the woods.
SOME FINAL SUGGESTIONS AND WORDS OF ADVICE
The following are words of advice to persons interested in nature
and curious about their surroundings, who are planning a trip to Dog
Island or to any seashore.
Try to go beachcombing at different times of the day -- e.g. at
very low tides, early in the morning after a very high tide or rough
surf, etc. When doing so, be on the lookout for organisms not
commonly found on the shore of a sandy beach, but washed up on the
beach from their offshore pelagic or oceanic benthic habitats.
For example, many of the Ophiuroideans such as the hairy or spiny
brittlestar are not commonly found on the beach but after rough seas
can be washed up on pieces of sponge or wrapped around sea whips.
Always look closely at pieces of washed-up sponges or sea whips ripped
from the sea bed -- break the sponges apart, look in the openings and
cavities etc. for small brittle-stars such as the small bright red
spiny brittle star (Ophiothrix) or small dorso-ventrally flattened
eroded porcelain crabs and the larger more colorful cherry striped
porcelain crab. Young stone crabs often seek shelter in sponge
cavities and crevices.
Be careful about picking up or collecting what initially appear
to be empty shells. They may contain hermit crabs that have retracted
into them and are not visible. One year a student picked up what he
thought was an empty shell and put it in a collection bag. After a
short time he heard something moving in the bag and looked in to find
a small dwarf octopus. When he reached in to take it out the octopus
grabbed onto his finger and delivered a painful bite.
One very large vase sponge found washed up in January 1990
contained a mature stone crab in one of its chambers and one smaller
sponge collected on 1-5-90 contained several young stone crabs, a
small snapping shrimp, small brittlestars, and a small Atlantic
needlefish. When exploring the seashore take the time to examine
things that might seem uninteresting at first glance.
Lastly, you are encouraged to use your Dog Island experience as
an opportunity to engage in activities that are not part of your
normal routine. Manage your time effectively. Set aside several
hours each night for serious study, so you can use daylight hours for
exploring the beach and the island. Plan to spend some time each day
(esp. in the early morning and late afternoon) bird-watching and
working on your bird list and bird identifications. Challenge yourself
by trying some long hikes, by trying some new foods or altering some
of your eating habits (e.g. junk foods, beer every weekend). Don't
hesitate to explore just because it's raining.
If you find any litter while walking and can conveniently carry
it back and properly dispose of it, please do so.
Don't stay up late every night playing cards and sleep in late
every morning. Get up early on occasion and walk on the beach and
witness a sunrise. Walk on the beach at night. Lay on your back and
contemplate the stars. Spend some time alone. When you hike on the
beach or on the island paths, often do so in silence, so that you are
tuned into the sounds of nature. Get up early on the morning of a
very low tide and explore exposed sand bars; you'll likely see animals
not normally visible.
.. Fotheringham, Nick. 1980. Beachcomber's Guide to Gulf Coast Marine
Life. Gulf Publishing Co., Houston, TX
.. McIntyre, Judith W. 1989. The Common Loon Cries for Help. Nat'l
Geographic, April 1989
.. Rudloe, Jack. 1984. The Erotic Ocean. 447 pp.
.. Ruppert, Edward & Richard Fox. 1988. Seashore Animals of the
Southeast. Univ. of S. Carolina Press. 429 pp.
Persons interested in this information or who have any questions or
encouraged to contact Dr. Sandford
in writing or by e-mail.