Marine Care Ricketts Point Inc.
2007/8 Survey
of Intertidal Marine Life
Aim.
To record
all visible species of marine plants and animals and detect trends over time.
Assessment.
Anyone who wants
to assess the success of failure of the Ricketts Point Marine Sanctuary
should study trends and changes in the statistics and species below.
Sites and Surveys.
Five shore platforms,
including one outside the sanctuary, were surveyed four times a year (Autumn
07, Winter 07, Spring 07 and Summer 08),
20 surveys
per year in all.
RESULTS
Compilation of Results. I.T.: Barbara Cameron. Analysis
and Comments: Bob Whiteway.
Our thanks are
due to the Reefwatch Survey Team: Erika Anderson, Jim Anderson, Peter and Fran
Dedrick, Jacqueline and Katie Flynn, Gez Pankovics, Rochelle Foley,
Esther Greig, Lee Goller,
Sharon Gibleth, Sarah Jacob, Mel Mitchell, Kirsty Manger, Margaret Norton, Val Royle,
Gabby Shaw, Bob Whiteway.
1a. Total number of sanctuary species
recorded: 72. This figure is an indicator of
biodiversity.
Comment.This
compares with 68 species the year before. The number of species observed
therefore increased by 4, or 6% over the last year.
It has increased by 12 species, or 20%,
since the inception of the surveys in 2003/4.
1b. Number of species found at each survey
site:
|
Location |
2004/5 |
2005/6 |
2006/7 |
2007/8 |
Increase 2004/5
to 07/8 |
|
Table Rock Platform |
35 |
49 |
47 |
47 |
12/35=
34% |
|
Tea House Reef |
36 |
48 |
60 |
56 |
20/36=56% |
|
Banksia
Point Platform |
41 |
45 |
47 |
45 |
4/41=10% |
|
McGregor Rock Islet |
42 |
48 |
49 |
51 |
9/42=21% |
|
Sanctuary (above 4 sites) |
51 |
62 |
68 |
72 |
21/51=41% |
|
Picnic Point (control site) |
35 |
40 |
46 |
46 |
11/35=31% |
Comment. The number of species at all reefs has increased
greatly over the past four years.
This may be because:
(1) surveyors
were able to identify more species (only identified species are
recorded),
(2) surveyors
became more skilled at finding creatures.
However, any improvement in the future
will be more significant.
Notice that Tea House Reef and Banksia Point seemed to have topped out.
2. Number of species found, by season
(measured through 2007 / 2008):
|
Location |
Autumn 2007 |
Winter 2007 |
Spring 2007 |
Summer 2008 |
|
Table Rock Platform |
39 |
29 |
27 |
34 |
|
Tea House Reef |
31 |
46 |
31 |
31 |
|
Banksia
Point Platform |
29 |
28 |
33 |
31 |
|
McGregor Rock Islet |
37 |
30 |
33 |
34 |
|
Picnic Point (control site) |
30 |
21 |
26 |
33 |
|
Total all locations |
166 |
154 |
150 |
163 |
Comment: The number of species found is greatest in
autumn, then in summer/winter, and the least found is in spring.
These results need to be tested
over a long time as tide levels on a particular day can vary and affect the
result for that season.
3. 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. Some different phyla look similar, e.g. Corals and some
Bryozoans, but some different phyla look dissimilar, e.g. Crustaceans and Molluscs such as Crabs and Shellfish. Only one phylum out
of the twelve has bones as we do. They are very different from us.
3a. Number of Phyla represented 2007/8 (all
platforms): 12
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. A flat worm (Phylum platyhelminthes)
was seen in a rock pool this year, thus adding a phylum to the list.
3b. Phyla and number of species in each,
2007/8:
|
Phylum |
All
Sanctuary |
Picnic
Point |
|
Green Seaweeds |
5 |
3 |
|
Brown Seaweeds |
10 |
6 |
|
Red Seaweeds |
2 |
3 |
|
Magnoliophyta |
1 |
0 |
|
Cnidaria |
3 |
3 |
|
Echinoderms |
7 |
5 |
|
Molluscs |
25 |
18 |
|
Crustaceans |
12 |
3 |
|
Platyhelminthes |
1 |
0 |
|
Annelida |
2 |
2 |
|
Cordata |
3 |
1 |
|
Bryozoans |
1 |
0 |
|
Total |
72 |
44 |
Comment. The most successful
phyla, by number of species, are, in order:
Molluscs, 25 species
Crustaceans,
12 species
Cnidaria, 7 species.
Seaweed species are also
prominent, especially brown seaweeds.
Molluscs can seal themselves off during low tide
and are also protected by their shells against predators. They are the best
suited to survive on near shore platforms and reefs.
Any future change in these
numbers would require analysis as the functioning of the ecosystem may be
implied.
4. Maximum number of species found in a
single survey:
|
Location |
2003/4 |
2004/5 |
2005/6 |
2006/7 |
2007/8 |
Increase 2003/4
to 07/8 |
|
Table Rock Point |
25 |
29 |
35 |
34 |
39 |
14/25=56% |
|
Tea House Reef |
26 |
26 |
34 |
44 |
46 |
20/26=77% |
|
Banksia
Point Platform |
26 |
30 |
32 |
33 |
33 |
7/26=27% |
|
McGregor Rock Islet |
33 |
35 |
38 |
33 |
37 |
4/33=12% |
|
Picnic Point (control site) |
26 |
28 |
32 |
35 |
33 |
7/26=27% |
Comment: The
increases, some extremely large, result from improved survey skills and
knowledge of species and their niches, and sometimes on lower tide heights.
Even so, it would suggest possible
improvement in the health of ecosystems, especially if maxima keep increasing. Tea
House Reef is outstanding.
5.
Inter-tidal Sanctuary Survey: Number of Sightings at whole Sanctuary (Maximum
possible: 16).
16 seasonal surveys were conducted over all four locations,
March 2007 to February 2008.
KEY: C: Coastal Invertebrates of
|
Sightings: 0 |
Sightings: 1-4 |
Sightings: 5-8 |
Sightings: 9-12 |
Sightings: 13-16 |
|
Green Seaweeds Caulerpa remotifolia S99 Cladophora feredayi S93 E30 Enteromorpha compressa E29 Caulerpa longifolia S98 |
Caulerpa brownii S97 Caulerpa geminata S97 |
|
|
Codium fragile S97 Enteromorpha intestinalis S89 Ulva sp S88 |
|
Brown Seaweeds |
Ectocarpus fasciculatus S61 Leathesia difformis S64 Petrospongin rugason S63 Scytosiphon lomentaria S65
Zonaria Sp. S73 |
Colpomenia sinuosa S64 Cystophora moniliformis S79 Ecklonia radiata S74 |
Caulocystis uvifera S81 |
Capreolia implexa (goldy
brown tufts or mat) Hormosira banksii S13 |
|
Red Seaweeds Ceramium sp. S52 Ligora harveyana S19 |
|
|
Corallina officinalis S18
Encrusting corallines S20 |
|
|
Magnoliophyta |
Sarcocornia quinqueflora E111 |
|
|
|
|
Cnidaria |
|
|
|
|
|
Anemones |
Anthothoe albocincta, E127 Aulactinia veratra, E127 |
|
|
Actina tenebrosa E126 |
|
Jellyfish Catostylus mosaicus E147 |
|
|
|
|
|
Echinoderms |
|
|
|
|
|
Seastars Parvulastra(Pateriella)exigua E345 Petricia vermicina E341 |
Allostichaster polyplax E350 Tosia australis E337 Uniophora granifera E349 |
|
Coscinasterias calamaria (muricata)
E348 |
Pateriella calcar E345 |
|
Urchins |
Heliocidaris erythrogramma E365 |
|
|
|
|
Sea
Cucumber Taeniogyros roebucki C155 |
|
|
|
|
|
Molluscs |
|
|
|
|
|
Chitons Cryptoplax striata C21 Notoplax subspeciosa |
Ischnochiton australis Ischnochiton elongatus |
Plaxiphora albida, E224 Ischnochiton variegates C14-16, E220-1 |
|
|
|
Winkles,
Winks, Whelks Top Shells,
etc Austrocochlea concamerata E241, photo E244 |
Austrocochlea constricta E240 Battillaria verata (australis) E247 Haliotis rubra E227 |
Nodilittorina unifasciata E245 Thais orbita
W18 |
Austrocochlea odontis E241 Nerita atramentosa E244 |
Austrocochlea porcata E240 Bembicium melanostomum E245 Bembicium nanum E244 Cominella lineolata E262 Lepsiella vinosa E258 Turbo undulatus
E242 W18 |
|
Limpets Notoacmea candida E232 Notoacmea flammea? E236 C32 |
Onchidella patelloides E269 Siphonaria funiculata E269 |
|
Patelloida alticostata E234 |
Cellana tramoserica E233 Collisella granulosa W21 Siphonaria diemenensis E267 |
|
Bivalves Barbatia pistachio E285 Electroma georgiana (winged) E290 Saccostrea glomerata (oyster) E295 |
|
Mytilus planulatus (edulis) E286 |
|
|
|
Crustaceans (Ph.Arthropoda) |
|
|
|
|
|
Shrimp,
etc. |
Palaemon serenus E191 Paridolea munda D45, SL Penaeus plebejus E189 |
|
|
|
|
Barnacle Balanus variegatus C108 |
Chthamalus antennatus? L62 + MCRP photo Tetraclitella purpurascens E173 Tesseropora rosea E173 |
|
Elminius modestus E175 W25 |
|
|
Crabs Haliocarcinus ovatus E208 Naxia E205-6 W7 (sketch) Nectocarcinus integrifrons E209 Paragrapsus laevis E214 Pilumnopeus serratifrons W24 Pilumnus tomentosus E212 |
Cyclograpsus audouinii E213 |
Brachynotus spinosis E215 Helograpsus haswellianus E214 |
|
Carcinus maenas E208 W24 |
|
Perinereis sp. (worm) E158 |
|
|
|
Galeolaria caespitosa E162 |
|
Phylum Platyhelminthes |
Notoplana australis (brown, flat) E152 |
|
|
|
|
Phylum Cordata Pyura stolonifera (Conjevoi) E379, W27 |
Alabes dorsalis (Eel) E413 Dragonet Oyster Blenny 529 Tasmanian Blenny |
|
|
|
|
Bryozoans
E321-326 |
Spp.? |
|
|
|
Comment: Species that have not been sighted (left column) may be becoming
locally extenct. Those sighted only 1 to 4 times are
similarly endangered.
All species can be compared
with their sightings number in subsequent years and, if diminishing, there may
be cause for concern about the species.
6. Birds
Seen in 2007 and 2008: Silver Gulls,
Pacific Gulls, Crested Terns, White-faced Herons, Pelicans, Black Swans, Pied,
Little Pied and Little Black Cormorants,
Little Ravens, Australian
Grebes.
Seen in 2008: Common Mynas and Masked
Lapwings.
Last year: 12, this year: 13.
Comment:
The bird population has remained relatively unaltered over the past twelve
months.
*** Final Comment and Alert
***
Statistically, the results indicate improvement in
biodiversity over the years of Sanctuary protection.
But some species have been sighted once or only a few
times. These are sliding towards local extinction.
To focus on this, we have added a new analytical tool. All
species are now listed according to number of sightings.
Look at Crabs, for example, under the Crustaceans section
of this tool. There are ten species. Most were not sighted at all and the other
few were rarely sighted. Only Carcinus maenas was sighted virtually all the time. And that is a
foreign crab from
Look carefully at this new tool.
It is sounding some ominous warnings.
Please keep this report for analysis and comparison with future
years.
Bob Whiteway.