Marine Care Ricketts Point Inc.
2006/7 Survey
of Intertidal Marine Life
Aim.
To record
all visible species of marine plants and animals and detect trends over time.
Sites and Surveys.
Five shore platforms,
including one outside the sanctuary, were surveyed four times a year (Autumn
06, Winter 06, Spring 06 and Summer 07),
20 surveys
per year in all.
RESULTS
1a. Total number of sanctuary species
recorded: 68. This figure is an indicator of biodiversity.
Comment. This compares with 62 species the year before. The number of species observed
therefore increased by 6, or 10%.
1b. Number of species found at each
survey site (first figure is 2004/5, second figure is 2005/6, third figure is 2006/7):
Table Rock Platform: 35, 49,
47
Tea House Reef: 36, 48, 60
Banksia Point Platform: 41, 45, 47
McGregor Rock Islet: 42, 48,
49
Sanctuary (above four sites):
51, 62, 68
Picnic Point (control site):
35, 40, 46
Comment. As noted, biodiversity (number of
species) appears to have improved by 10% (from 62 to 68 species) on sanctuary
platforms over the year.
2. Number of species found, by season
(measured through 2006 / 2007):
(figures are
for Autumn 06, Winter 06, Spring 06, Summer 07)
Table Rock: 34, 34, 29, 30
Tea House Reef: 44, 25, 31,
38
Banksia Reef: 28, 33, 30, 33
McGregor Islet: 33, 30, 33,
33
Picnic Point: 35, 33, 29, 22
Totals for all locations:
174, 155, 152, 156
Comment. The patterns to emerge from the table
are that numbers were steady or increased at all sanctuary sites from spring to
summer and increased at Banksia Reef from Autumn 2006 to Summer 2007 by 18%. Also numbers declined
steadily throughout the year at the control site Picnic Point.
PHYLUM ANALYSIS
Definition of Phylum: This is a division of living things that arose from a
separate branch of evolutionary development. Thus all the three seaweeds are
separate phyla and followed different evolutionary paths.
4a. Number of Phyla represented (all
platforms): 11
Comment. This is a surprising number of phyla to
be found in such a tiny area as a shore platform. The average person would
generally be aware of only a few phyla on land: chordates, insects, worms,
flowering plants and conifers. Thus, the phyla-diversity on shore platforms
appears to be relatively large.
4b. Phyla, and number of species in
each, 2006/7 (first figure is Sanctuary Reefs, second figure is Control Site
(Picnic Point):
Green Seaweeds: 6, 4
Brown Seaweeds: 10, 7
Red Seaweeds: 2, 2
Magnoliophyta: 1, 0
Cnidaria (Anemones,
jellies etc): 4, 3
Echinoderms (Stars,
urchins, etc): 4, 5
Molluscs
(Shellfish etc): 24, 17
Crustaceans
(Crabs, shrimps, etc): 11, 5
Annelida (Segmented
worms): 2, 1
Cordata (Sea
squirts, etc): 3, 2
Bryozoans: 1, 0
Comment. Molluscs,
notably shellfish, dominate. They are well adapted to survive for short periods
out of the water and have hard shells to ward off predators that have such easy
access to prey. However, some phyla may be underrepresented because of human
interference. Crabs, for instance, have been a target of both
children and poachers, as well as their natural predators - birds, fish,
molluscs and so forth.
5. Record number of species found in a
single survey (figures are for 2003/4, 2004/5, 2005/6, 2006/7, respectively):
Table Rock Point:, 25, 29,
35, 34
Tea House Reef: 26, 26, 34, 44
Banksia Point: 26, 30, 32, 33
McGregor Rock: 33, 35, 38, 33
Picnic Point: 26, 28, 32, 35
Comment: These figures suggest what is
indicated generally by the surveys: that biodiversity is increasing from year
to year. However some species of sea stars and crabs may have diminished since
the sanctuary was declared. Also, improvement in the over-all number of species
may be partly the result of better observational techniques and awareness.
6. List of all inter-tidal platform species identified
during 20 seasonal surveys at 5 sites, March 2006 to Feb. 2007.
Inter tidal Survey Sheet
KEY: C: Coastal Invertebrates of
Green Seaweeds (6) meaning six species in
this Phylum
Caulerpa brownii, S97
Caulerpa remotifolia, S99
Caulerpa longifolia, S98
Codium fragile, S97
Enteromorpha intestinalis, S89
Ulva sp, S88
Capreolia implexa (goldy brown tufts or mat)
Caulocystis uvifera, S81
Colpomenia sinuosa, S64
Cystophora moniliformis, S79
Ecklonia radiata, S74
Ectocarpus fasciculatus, S61
Hormosira banksii, S13
Leathesia difformis, S64
Magnoliophyta(1)
Sarcocornia quinqueflora E111
Cnidaria,
(4)
Anemones
Actina tenebrosa, E126
Anthothoe albocincta, E127
Aulactinia veratra, E127
Jellyfish
Catostylus mosaicus, E147
Seastars
Allostichaster polyplax, E350 *
Coscinasterias calamaria (muricata), E348
Pateriella calcar, E345
Parvulastra (Pateriella) exigua, E345 *
Tosia australis, E337
Urchins
Heliocidaris erythrogramma, E365
Molluscs
(24)
Chitons
Cryptoplax striata, C21
Plaxiphora albida, E224
Ischnochiton variegates, C14-16, E 220-1
Winkles, Winks, Whelks, Top Shells, etc.
Austrocochlea constricta, E240
Austrocochlea odontis, E241
Austrocochlea porcata, E240
Battillaria verata, (australis), E247
Bembicium melanostomum, E245
Bembicium nanum, E244
Cominella lineolata, E262
Lepsiella vinosa, E258
Nerita atramentosa, E244
Nodilittorina unifasciata, E245
Thais orbita,
W18
Turbo undulates, E242, W18
Limpets
Cellana tramoserica, E233
Collisella granulosa, W21
Notoacmea flammea?,
E236, C32
Onchidella patelloides, E269
Patelloida alticostata, E234
Siphonaria diemenensis, E267
Bivalves
Blue-ringed octopus
Electroma Georgiana (winged), E290
Mytilus planulatus (edulis), E286
Crustaceans. (Phylum Arthropoda)
(12)
Shrimp
Palaemon serenus, E191
Barnacle
Balanus variegatus, C108
Elminius modestus, E175, W25
Chthamalus antennatus?, L62 + MCRP photo *
Crabs
Brachynotus spinosis, E215
Carcinus maenas, E208, W24
Cyclograpsus audouinii, E213
Helograpsus haswellianus, E214
Leptigrapsus varigatus, E214
Pilumnopeus serratifrons, W24
Naxia, E205-6, W7
Galeolaria caespitosa (d =dead), E162
Notoplana australis (brown, flat),
E152
Phylum Cordata
(4)
Alabes dorsalis (Eel), E413
Bovichtus augustifrons E484
Oyster Blenny, 529
Pyura stolonifera (Conjevoi),
E379, W27 *
Bryozoans E321-326 (1)
Total: 72 species at 5 sites.
* Found
at Picnic Point only.
Birds (all
sites): Silver Gulls, Pacific Gulls,
Crested Terns, White-faced Herons, Pelicans, Black Swans, Pied, Little Pied and
Little Black Cormorants,
Starlings,
Little Ravens, Australian Grebes.