Biology of the Seashore
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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.


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 January '96,

I. Phylum PORIFERA [Sponges]

1. Orange Devil's finger - Axinella polycapella
2. Loggerhead sponge
3. Encrusting sponge (Haliclona)
4. Lavender tube sponge
5. Crumb-of-bread sponge (Halichondria)
6. Reddish vase or basket sponge (Ircinia)
7. Branching vase sponge (Callyspongia)
8. Hermit crab sponge (Taxonomic status undergoing revision)

In the past literature the hermit crab sponge has been identified as Xestospongia halichondriodes or as Suberites compacta. Both are incorrect. The true identity of the sponge, as a sub-population of Spongosorites suberitoides, was clarified by Sandford and Kelly-Borges 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 '95

II. Phylum CNIDARIA (formerly called the COELENTERATA)

A. Class: Hydrozoa
B. Class: Scyphozoa (true jellyfish; pelagic habitat)
1. Moon jellyfish - Aurelia aurita
2. Edible jellyfish - Rhopilema
3. Cannonball jellyfish - Stomolophus meleagris ("Cabbagehead")
4. Stinging nettle jellyfish (common in '91, rare in '99)
C. Class: Anthozoa [anemones and corals]
1. Sea pansy - Renilla
2. Star coral
3. Ivory bush coral
4. Cloak anemone (or Hermit Crab anemone) - Calliactis tricolor
5. Sea whips - Leptogorgia virgulata
III. Phylum CTENOPHORA ["comb jellies"]
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
2. White crust bryozoan - Membranipora
3. Staghorn bryozoan - Schizoporella

VII. Phylum ANNELIDA [segmented worms]

A Class: Oligochaeta [earthworms]
B. Class: Hirudinea [leeches]
C. Class: Polychaeta
1. Clam worm - Nereis
2. Parchment tube worm - Chaetopterus
3. Plumed worm or shaggy parchment tube worm - Diopatra
4. Ice cream cone worm (or trumpet worm) - Cistenides gouldii [new name Pectinaria gouldii (1 found '88; many empty cones found in '90 - '92). This animal builds a cone-shaped hollow tube exactly one sand grain thick. As it grows it carefully selects and perfectly fits/mortars new grains into place. Tube is rigid/fragile]
5. Lugworm - Arenicola
6. Soda straw worm
7. Bamboo worm - Clymenella
8. Serpulid worm (Eupomatus) - constructs calcareous tubes on the surfaces of shells.
9. Scaleworm


A. Class: Amphineura (Polyplacophora) [chitons]
1. Common chiton
B. Class: Scaphopoda [tooth shells]
C. Class: Pelecypoda (Bivalvia) [bivalves]
1. Common jingle (2 very diff. valves)
2. Pen shell (both rigid and saw-toothed)
3. Common oyster
4. Giant heart cockle - Dinocardium
5. Prickly cockle
6. Coquina clam - Donax variabilis
7. Kitten's paw
8. lucine clam
9. Cross-barred venus clam
10. Fl. spiny jewel box clam
11. Quahog clam
12. Sun ray venus clam
13. Angel wing clam
14. Channel duck clam
15. Common bay scallop
16. Ponderous ark
17. Cut-ribbed ark
18. elegant dosinia
19. Boring clams
20. Jackknife clam
21. Macoma clam
22. common egg cockle
23. Atl. surf clam
24. Turkey wing ark
25. Atl. wing oyster
26. Tulip mussel
27. Calico scallop
28. Broad-ribbed cardita
29. Jingle shell
D. Class: Gastropoda [univalves - snails, whelks, etc.]
1. Keyhole (cayenne) limpet - Diodora cayenensis
2. Crown conch - Melongena corona
3. Florida fighting conch - Strombus alatus
4. Common baby's ear - Sinum perspectivum
5. Common Atlantic slipper snail - Crepidula fornicata
6. Pear (or fig) whelk - Busycon spiratum
7. Left-handed (or lightning) whelk - Busycon contrarium
8. Worm shell - Vermicularia
9. Bubble shell - Acteocina bidentata
10. Moon snail or Shark's eye - Polinices duplicatus
11. Florida horse conch - Pleuroploca gigantea
12. Lettered olive - Oliva sayana
13. Marsh periwinkle - Littorina irrorata
14. Common nutmeg - Cancellaria reticulata
15. Atlantic Fig shell - Ficus communis [very common in '95]
16. Atlantic auger - Terebra dislocata
17. Junonia volute - Scaphella junonia
18. True tulip - Fasciolaria tulipa
19. Banded tulip - Fasciolaria hunteria
20. Gulf oyster drill - Urosalpinx perrugata
21. Chestnut turban - Turbo castanea [Look for its calcareous operculum on the beach]
22. Scotch bonnet - Phalium granulatum
23. Apple murex - Phyllonotus pomum
24. Lace murex - Chicoreus dilectus
25. Fl. rock shell - Thais haemastoma floridana
26. Florida cone - Conus floridanus
27. Common Eastern Nassa - Nassarius vibex
28. Cancellate cantharus - Cantharus cancellarius (Conrad, 1846)
29. Sooty Sea Hare - Aplysia morio [rare in '86 & '87; common in '88 and '92; prolific in '89; none seen in '90; 8 washed up side near Tyson's harbor at spring low tide on 1/18/92]
30. Frilled or ragged sea hare - Bursatella leachii [same as Aplysia above, but two found in '91; one in '92]
E. Class: Cephalopoda
1. Common octopus [over 200 found dead in bay in '99]
2. Dwarf octopus - Octopus joubina [look for dwarf octopus washed up on the beach or hiding in empty shells]
3. Atlantic brief squid
Class: Merostomata - the Horseshoe crab, Limulus polyphemus
Class: Crustacea
A. Barnacles -- e.g. Acorn barnacles (Ivory and striped barnacles) Sea whip barnacle (Balanus galeatus)
B. Decapod (10-legged) crustaceans (shrimp,lobster, crabs etc)
1. Peppermint shrimp (a cleaning symbiont)
2. White shrimp
3. Pink shrimp
4. Brown shrimp
5. Mantis shrimp
6. Spider crab
7. Stone crab
8. Calico box crab
9. Snapping shrimp
10. Porcelain crab
11. Marsh crab (Sesarma)
12. Common fiddler crab (Uca pugilator)
13. Blue crab (Callinectes sapidus)
14. Flame-streaked box crab
15. Common mole crab - Emerita
16. Arrow crab
17. Ghost crab (Ocypode quadrata)
18. Speckled crab (Arenaeus cribrarius)
19. Ghost shrimp (Callianassa)
20. Iridescent swimming crab (Portunus gibbesi)
21. porcellanid crabs - sm. red and white crabs; hermit symbionts
22. sand dollar crabs - sm. crabs that live on sand dollars
23. sm. porcellanid crab (Polyonyx) - symbiont w/ parchment tube worm
Hermit crabs:
1. Red flat-clawed (or dimpled) hermit - Pagurus impressus
2. White flat-clawed hermit - Pagurus pollicaris
3. Filter-feeding hermit - Paguristes hummi
4. Long-wristed (or dwarf) hermit - Pagurus longicarpus
5. Giant red hermit - Petrochirus diogenes [Common in '96]
6. Striped hermit - Clibanarius vittatus This hermit crab dominates the marsh and Dr. S's bay study site in the summer.
Blue 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 shallow 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 inlet.


A. Class: Holothuroidea [Sea cucumbers]
1. Striped sea cucumber (Thyonella)
2. Speckled sea cucumber (Theelothuria)
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)
3. Orange starfish (Echinaster) (common in '99)
4. Pointed (or Burrowing)(or margined) sandstar (Astropecten)
C. Class: Echinoidea [sea urchins, sand dollars, sea bisquits]
1. Purple sea urchin (Arbacia punctulata) (long-spined)
2. Short-spined sea urchin (Lytechinus)
3. Brown sea bisquit
4. Keyhole urchin (better known as 5-hole sand dollar) (Mellita)
5. Heart urchin [thousands of tests washed up on beach in '88, superficially resembling turtle eggs]
6. Arrowhead sand dollar
D. Class: Ophiuroidea [brittle stars]
1. 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]
2. Hairy legs brittlestar (a small spp. found in/on sponges)
3. War-legs brittlestar
Subphylum: Tunicata (Urochordata)
A. Tunicates [Sea squirts]
1. Sandy sea squirt (Molgula)
2. Leathery or Rough sea squirt (Styela)
3. Sea pork (Amaroucium stellatum) - a colonial form; colonies often wash ashore after a storm, looking like chunks of pinkish-white salt pork on the sand. In January we have pork,in a variety of colors (pink, yellow, bluish-green)
4. Sea liver tunicate
Subphylum: Vertebrata
B. Class: Pisces [marine fish] (this is only a partial list)
1. N. sea horse (Hippocampus)
2. scrawled cowfish
3. needlefish
4. batfish
5. electric ray
6. amberjack
7. sea robin
8. skate
9. dogfish shark
10. bonnethead shark
11. lizard fish
12. toadfish
13. striped mullet
14. tongue fish
15. Atlantic sting ray
16. gray triggerfish
17. inland silversides
18. striped burrfish
19. longnose killifish - common "minnow" that schools in the temporary semi-isolated lagoons of barrier islands

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: Reptilia
1. loggerhead sea turtles nest on Dog Is. in the summer.
2. Alligator (are sighted in fresh water ponds/marsh in summer)
3. Diamondback terrapin
4. E. Box turtle and Gopher tortoise [one found Aug. '89 in woods W. of airstrip; shell measured 6 and one-half inches long)
5. Water mocassins (cottonmouth) and pygmy rattlesnakes are on the island. On 1/10/91 a 3' long dark brown snake w/ black markings was found curled up on the landing strip. When Dr. S moved close it opened its mouth wide in a threat display. The fangs and very white mouth interior identified it as a cottonmouth or water mocassin. Water mocassins were seen sunning near the E. end marsh several times in January '92
6. Other snakes reported on the island, and sometimes seen in January, include: black racer, corn snake, indigo snake, and brown water snakes (closely resemble cottonmouth)
7. Striped skink, a kind of lizard
8. Common anole (Florida "chameleon")
E. Class: Aves

Coe College students spend time bird-watching and learning the birds of Dog Island, and each student keeps a list of all species seen during our stay on the island. Over 100 different species can be found on Dog Island in January, but students are only expected to be familiar with the identification and naming of the following:

1. sanderling
2. "peep" sandpipers
3. willet
4. great blue heron
5. black-crowned night heron
6. snowy egret
7. great egret
8. Louisiana heron
9. brown pelican
10. kingfisher
11. killdeer
12. common loon
13. grebe
14. mallard duck
15. robin
16. mockingbird
17. herring gull
18. ring-billed gull
19. Bonaparte's gull
20. laughing gull
21. Forster's tern
22. royal tern 23. double-crested cormorant
24. Amer. oystercatcher

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. bird checklist.

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: Mammalia
1. 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):
2. Raccoon
3. river otter
4. black cotton rat
5. feral domestic cats
6. feral rabbits (Easter bunnies that someone released)

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 occur on Dog Island, likely on the West end.


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 salt marshes on the E. end of the island. The other common plant of the salt marsh habitat is Juncus, commonly called "needle rush". Juncus is 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.


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 comments are encouraged to contact Dr. Sandford in writing or by e-mail.

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