SPECIES LIST:
Compiled by:Donna Gibbs of the Vancouver Acquarium on dives made at Rosedale Rock, West Race Rocks and William Head in the summer of 1997. Groupings are made in Phylums or Divisions.
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Dive 433 – Rosedale, Race Rocks – June 13, 1997 |
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Dive 434 – West Race Rocks – June 13, 1997 |
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Dive 431 – William Head, Vancouver Island – June 12, 1997 |
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The first year Pearson College students are doing their IB Group 4 science Project coursework this year on Race Rocks.
The following is a list of preliminary ideas given to the 100 students of the first year who will all be participating in an interdisciplinary study of scientific problems at the Race Rocks Ecological Reserve on March 26, 1997.
The list is intended to stimulate the students to generate research problems to be planned in groups before-hand and then investigated on that date.
Scheduled for: Mar 26 1997
The following is a list of preliminary ideas given to the 100 students of the first year who will all be participating in an interdisciplinary study of scientific problems at the Race Rocks Ecological Reserve on March 26, 1997.
The list is intended to stimulate the students to generate research problems to be planned in groups before-hand and then investigated on that date.
| BACKGROUND :It is intended that,students can access this file as a resource for an assignment in high school biology or college ecology coursers. For several years now, students of biology and environmental systems classes of Pearson College have been doing informal studies on the tidepools of Race Rocks. In April of 1996 we started to make some systematic records of some of the pools and establish a data base to which we could add in the future. The following represents the beginning of our tidepool work. |
 Pool 2= 50 degrees(compass bearing) Pool 2= 50 degrees(compass bearing) This is covered only at high tide. The predominant life form here are swarms of a small, 0.5mm reddish brown crustacean called Harpacticoids (see video)  Pool 1= 75 degrees (compass bearing). This is a high level pool. It would be flooded only by surge and ocean swells, especially during storms. Tiana and Melina are shown here taking measurements. |
| PURPOSE:by Michal Kozak
Tide pools are completely separate systems from that of the rocky shore. They form a sort of intermediate situation between the coastal sea and the well-drained intertidal zone, and thus give insights into factors controlling the structure and function of these two bordering systems. Tide pools are suitable for various student projects, similar to the one that we did. It is because of the amazing diversity of life and the wealth of physical, biological, and chemical processes in them. For instance, they show the importance of the desiccation factor on the open shore and they are also ideal observing pH and buffering phenomena. Their generally manageable proportion and simple ecosystems mean that thorough projects in tide pools can be undertaken in a short period. PROCEDURE: On Friday, 12th of April/96 during our block of environmental systems we went by boat to Race Rocks. We moored at the docks and then we went through across the island to the rocky shore. Besides numerous seagulls we saw there several tidepools. The tide level at that time was quite high (1.8 m), so at a lower tide we could have seen more tide pools. There we observed 3 different tide pools that were found close to the red peg, number 6. At each tidepool we measured the following :
We recorded our results and processed them ,thus trying to find general trends in the physical factors observed. The next Wednesday, we went to Race Rocks again. However, this time the tide was lower (0.9 m) which enabled us to observe tide pools at lower levels. We again followed the same procedure as described above. 
This map presents the horizontal distribution of the tide pools around a permanently installed reference peg on the Western side of Great Race Rock. We have over 15 of these reference pegs around the island. Many are used for subtidal transect work and surveys. Peg #6 is particularly well suited for intertidal work on this Western side of the island. Intertidal transect photos from the peg#5 location may be found at the Race Rocks Section of The Transect File. The magnetic compass bearings of the pools from the reference peg are listed below:  In May 2004 the biology class measured features of several pools. They are here at pool 3. Pool 3= 0 degrees. (compass bearing)
 bleached sea grass, as this is early spring. Students of the biology class, 2005 beside Pool #6 Pool 6= 205 degrees (compass bearing). . See the reference below to research work done on this pool by Dr. Anita Brinckmann Voss.
THE TEMPERATURE OF THE TIDE POOLS. Temperature of tide pools was measured for overall differences between pools and for stratification within pools BIOTIC FACTORS OF THE POOLS A species list was made of the pools and graphs were made to compare the numbers of plant and animal species in each pool.
ELEVATION OF THE POOLS: A profile of the vertical distribution of the pools was done by Tamas in the spring of 1998. From this we can make hypothesis about correlations with vertical levels and differences in the pools. THE pH OF THE POOLS
PUBLICATIONS ON TIDEPOOLS:Brinckmann-Voss, A. 1996. Seasonality of Hydroids (Hydrozoa, Cnidaria) from an intertidal pool and adjacent subtidal habitats at Race Rocks, off Vancouver Island, Canada. Scientia Marina, 60 (1): 109-117This work done recently by Dr. Anita Brinckmann-Voss was in a tidepool (#6) adjacent to the ones we have been studying at Race Rocks. The purpose of her paper was “to provide information on the hydroids of a cold temperate tide pool with regard to seasonal occurrence, growth and regression, and reproductive periodicities.” She has reported an assemblage of 27 hydroid species and tracked their seasonal occurrence, growth, sexual maturity and systematics. Possible causes of hydroid species diversity are considered, including location of tide pool in an area of rapid tidal rapids, and shading by surfgrass and rock cliffs during low tide.Thomas, M.L.H.-1983. Marine and Coastal Systems of the Quoddy region, New Brunswick, Canada. Can. Spec.Publ.Fish.Aqua.Sci. 64: 1-306 This reference has been of use to us because it provides a classification scheme for tide pools and a series of charts and graphs which have provided useful models for our studies. Thomas notes that “Although there is a wealth of information on seashores, there is a paucity of information on tidal pools, particularly their functional aspects. There are no texts on pools and those on shores in general (Amos 1966; Carefoot 1977; Clayton 1974 ; Lewis 1964; Southward 1966; Stephenson and Stephenson 1972; Yonge 1949) provide little critical information about tidal pools. This undoubtedly results from the scarcity of scientific papers on tidal pools.”This file was prepared by the students of the Environmental Systems Classes and their teacher G.Fletcher. |
SCI. MAR., 60 (1): 89-97
SCIENTIA MARINA 1996 ADVANCES IN HYDROZOAN BIOLOGY, S. PIRAINO, F. BOERO, J. BOUILLON, P.F.S. CORNELIUS and J.M. GILI (eds.)
Seasonality of hydroids (Hydrozoa, Cnidaria) from an intertidal pool and adjacent subtidal habitats at Race Rocks, off Vancouver Island, Canada*
A. BRINCKMANN-VOSS
Department of Invertebrate Zoology, Royal Ontario Museum, 100 Queen’s Park, Toronto, Ontario M5S 2C6, Canada.
(Mailing address: P. 0. Box 653, Sooke, British Columbia VOS 1NO, Canada)
( now deceased) .
*Received November 29, 1994, Accepted October 20, 1995
SUMMARY: An assemblage of 27 hydroid species was reported from a tide pool in the lower rocky intertidal zone, and compared with 42 hydroids of the adjacent subtidal region. Location of hydroids within the pool, seasonal occurrence, growth and sexual maturity were tabulated, and some systematic aspects discussed . Possible causes of hydroid species diversity were considered, including location of the tide pool in an area of tidal rapids, and shading by surfgrass and rock cliffs during low tide.
Key words: tide pools, hydroids, seasonality, Pacific coast.
INTRODUCTION
Invertebrate species diversity is high around Race Rocks (48′ 18′ N, 123′ 32′ E), an archipelago in the Strait of Juan de Fuca between Vancouver Island, Canada, and Washington state, USA. (Fig.1,2). Although publications of marine invertebrates are available for the areas to the east and west of Race Rocks (Henkel, 1906; Fraser, 1913; Kozloff, 1983), information about invertebrates from Race Rocks is mostly limited to personal observations or unpublished reports: P. Breen, Pacific Biological Station Nanaimo, Dpt.Fisheries and Oceans; P. Lambert, curator of invertebrates, Royal British Columbia Museum; Garry Fletcher and student essays from Lester Pearson College of the Pacific: in Race Rocks Ecological reserves #97 publications list 1988-1994). Because of its rich biota, the area is now protected as an ecological reserve. Research on hydroids there, started in 1984, continues today by permit.
Taxonomic investigations have been published previously to characterize some of the hydroid species mainly from a tide pool on the west side of Great” (great is ommitted trom here on) Race Rocks (Brinck-mann-Voss 1988; Brinckmann-Voss et al., 1993) . However, information about the cornpositon and distribution of hydroid species in the pool is lacking, as is a comparison of its hydroid fauna with that of the surrounding intertidal and adjacent subtidal shelf.
The purpose of this paper is, therefore, to provide information on the hydroids of a cold temperate tide pool with regard to seasonal occurrence, growth and regression, and reproductive periodicities. This research is intended as essentially a faunal study rather than a dedicated ecological work employing methods and analysis such as described for rocky shores by Paine (1994).
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FIG. 1. Map of southwestern British Columbia,with location of the Race Rocks archipelago,
DESCRIPTION OF STUDY AREA
The study area may be classified as protected outer coast, the main island of Race Rocks being protected by surrounding rocks and reefs . The west and north sides of the island are swept by very swift tidal rapids with a maximum velocity of 3 m /s (Fig.2). The average maximum velocity for the first half of June 1995 , which included a neap and leap tide, was calculated at 2.7 m/s (Canadian Tide and Current Tables, 1995).
The tide pool studied here is located on the west side of the island in the low intertidal zone in the middle of the Pseudobalanus cariosus – Mytilus californianus – Pollicipes polymerus belt (Lewis, 1964; Ricketts and Calvin, 1968; Carefoot, 1977). It may be classified as “Ic” after the pool classification summarized by Thomas (1983). The pool surface emerges at 1.5 m above 0 tide level (0 represents the chart datum in Canadian Tide and Current Tables) (Figs.3,5).
FiG. 2. – Island of (Great) Race Rocks, with location of the tide pool
As: A .Opposing arrows: area of very strong tidal currents, changing
direction in ebb and flood tide.
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FIG. 3. – December tidal curve of Race Rocks (Victoria) area…… emersion period of tide pool (modified from Canadian Tide and Current Tables 1992).
Emersion of the pool surface is most obvious at leap tides. Although the pool may be exposed even at neap tides, waves and swells keep it awash, especially in stormy winter weather. During the emersion periods at leap tides, the pool does not drain and its water level changes are minimal. It is situated between a high cliff on the island side and a lower cliff toward the open sea. These two cliffs join at the north and south sides of the pool, thus forming a deep trough . Once emersed the pool is about 8m by 1.5m, slightly less wide in its northern part, with a maximum depth of 0.8m (Fig.4). It narrows in the middle with an exposed rock creating a small island (Fig.5). During incoming tide this is the first area to be flooded.
The surface temperature of the sea around Race Rocks varies during the year between 7 degrees C and 12 degrees C. Contrary to conditions in a shallow pool (without hydroids) 2m higher in the same area, surface and bottom temperatures in the lower and deeper pool, abundant with hydroids, scarcely differ from the sea temperature. Only during summer low tides, when the sun reaches the pool during the second third of the emersion period, are surface temperatures higher (2’C, rarely 42C )than the bottom temperatures or in the surrounding sea. Water temperatures were checked only February to October, because of the pool’s relative inaccessability in winter.
Unlike in the higher pool, salinities in the pool correspond with that of the adjacent sea (29-30%o, measurements provided partly by Garry Fletcher) from February to October.
No measurements of salinity and temperature were taken from November to January. However, the state of the surfgrass (Phyllospadix scouleri) lining the upper rim of the pool indicated that heavy winter rains in combination with low temperatures (Tokioka, 1963) impact the intertidal environment, including the rock pool. Lewis (1964), Carefoot (1977), and Thomas (1983) report on similar destructive effects of winter rains. The study area also encompassed the rocky infralittoral and subtidal, extending from 0-18m depth, to a distance of about 50 m from the shore around Race Rocks.
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Flci. 4. – Diagram of central area of tide pool, with locations of hydroids. NumL)ers represent the hydroict species listed in Table 1. Affow pointing fmm open water to tide pool: first water or spray during flooding. The rock in the center forms a small islet during emersion. The ledge is an underwater shelf about 10 cm below surface during emersion.
MATERIAL AND METHODS
Collections of hydroids from the tide pool were made from March to October, over a period from 1984 to 1994.
Hydroid specimens were returned live to the laboratory, where they were examined and some photographed. Many were cultured to establish their identity, especially when specimens were collected in the hydrorhiza stage only. Species, depth and location of the hydroids were mapped on a diagram on the site.
Samples from the sublittoral shelf were taken by divers. The samples that were collected included both hydroids and a variety of bottom material, such as kelp holdfasts, barnacles, and mussels. These substrates were examined for small hydroids in the laboratory.
RESULTS
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FiG. 5. – Cross-section of tide pool at area of rock in center of pool.
C: Lower low water of spring tide. A to C represent the intertidalregion. S: Surface of tide pool at 1.5 m tide level and lower tides.
P: phyllospadix scouleir belt, located 1.5 m higher in the pool than on the open shore, where it can be found at the border between the intertidal and subtidal, marked as C
Except for one hydroid species (Rhizogeton nudus) among the stalks of Pollicipes polymerus, no hydroids were found in the intertidal outside the pool between pool and infralitioral fringe.
Species composition of the pool and of adjacent subtidal regions was similar, with a few notable exceptions: luxurious colonies of Sarsia eximia and Phialella sp. occurred on the rhizomes of Phyllospadix sculeri (Zosteraceae, Angiospermeae) lining the rim of the rock pool, but these species were less abundant in the Phyllospadix scouleri belt of the infralittoral of the open coast, (for location of Phyllospadix scouleri see Fig.5). Conversely, larger species of the Sertulariidae were more diverse and abundant subtidally than in the pool. Plumularia setacea was common in the pool but less so subtidally, whereas Plumulara lagenifera was not found in the pool, but was abundant subtidally.
Hydroids of the tide pool were referrable to three groups. Group A showed marked seasonal cycles of activity and regression, with hydroid colonies represented during a dormant phase by hydrorhizae only. Species of group B were present periodically as small colonies, typically in early spring, and then enlarged during late spring and summer. Group C included species in which the activity patterns and colony sizes remained relatively unchanged throughout the year.
Included in group A was Hybocodon prolifer, abundant and fertile in late winter and spring, but reduced only to stolons in summer and fall. Sarsia eximia and Phialelia sp. (described by Boero 1987, but not named), living among the rhizomes of Phyllospadix scouleri plants (Zosteraceae), were reduced to hydrorhiza or to small colonies with a few sterile hydranths in late winter and spring. Both species occurred as large and fertile colonies in summer spreading occasionally onto the outer dead leaf sheadi of Phyllospadix or onto the surrounding rocks.
Peak reproduction was in June and July for Sarsia eximia and in September for Phialella sp.
Species of group B (e.g. Orthopyxis integral Obelia dichotoma, Garveia annulata, and Clavactinia sp.) were present as small patches in early spring. By late summer their colonies had enlarged and stolonal species covered wide areas on the rock walls of the pool. In Clavactinia sp., reduction and expansion of the same colony was observed over a period of two years.
Species assigned to group C changed little in colony size during the year. These included representatives of the families Stylasteridae, Plumulariidae, and Sertulariidae. This may be related to their morphology, as their hydranths are more protected through the extensive perisarc of the colony, than species of group A and B.
DISCUSSION
Systematics: The taxonomy of hydroids from the northeastern Pacific, and especially of the Leptothecatae (terminology after Cornelius, 1992), is inadequately known. A large number of species has been reported from the area by Fraser (1913,1937), and before him by authors including Nutting (190015), Torrey (1902), and Clark (1876, 1877). However, many specimens collected from Race Rocks and adjacent areas do not correspond with descriptions of such species, a problem discussed by Brinckmann-Voss (1983) and Mills and Miller (1987). Detailed monographic revision is therefore needed from hydroids of the northeast Pacific. Comparisons are warranted with the hydroid fauna of the northwest Pacific (Yamada, 1959; Naumov, 1960; Antsulevich, 1992; Antsulevich and Vervoort, 1993), and with that of the circumpolar Arctic (Broch, 1909), as done by Kramp (1959, 1965, 1968) for the hydromedusae.
Accordingly, several species in this paper were identified only to the genus level (Tables 1-3). Work is currently underway on the Plumulariidae from Race Rocks and elsewhere on the British Columbia coast (Brinckmann-Voss and Calder, unpublish data). Changes of family and genus were made of two species of Anthoathecatac. Hataia parva Hirai and Yamada 1965, previously assigned to the Clavidae, is assigned here to the Acaulidae. Features described in the original (Hirai and Yamada, 1965) and in recent (Yamada and Kubota, 1989) work on the species as to its solitary nature, mode of asexual reproduction, and presence of stenoteles, justified placing Hataia near the genus Acaulis Stimpson, family Acaulidae. A species identified as Hydractinia milleri Torrey 1902 in Morris et al. (1980) is tentatively referred to the genus Clavactinia Thomely as Clavactinia sp. because its gastrozooids have several whorls of tentacles (Millard, 1975). The species listed in Morris, Abbott and Haderlie and found in the Race Rocks area is distinguished from H. milleri Torrey in
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TABLE 1. Distribution of hydroids in the Race Rocks tide pool. Numbers refer to locations in the pool (as in Fig. 4).
Species
Anthoathecatae
Clavidae
Rhizogeton ezoense Yamada,1964
Eudendriidae
Eudendrium sp.
Bougainvilliidae
Bougainvillia ramosa (van Beneden , I 844)
Garveia annulata Nutting, 1901
Rhizorhagium roseum M.Sars, 1874
Rhysiidae
Rhysia fletcheri Brinckmann-Voss, Lickey, Mills, 1993
Hydractiniidae
Hydractinia armatata Fraser, 1940
Clavactinia sp.
Stylasteridae
Hataia parva Hirai and Yamada, 1 965
Tubulariidae
Tubularia marina Toney, 1902
Hybocodon prolifer L.Agassiz, 1 862
Corynidae
Sarsia eximia (Allman,1859) (on rhizomes of Phyllospadix)
Leptothecatae
Calycellidae
Calycella syringa (Linnaeus, 1767)
Aequoreidae
Aequorea victoriae (Murbach and Shearer, 1902)
Phialellidae
Phialella sp. (on rhizomes of Phyllospadix)
Haleciidae
Halecium pygmaeum Fraser, 1911
Campanularia ritteri Nutting, 1901
Canpanularia volubilis (Linnaeus,1758)
Laomedea exiguae M.Sars,1857
Orthopyxis integra (Mugillivray,1942)
Clytia sp. (on Mytilus)
Plumulariidae
having several purple eggs per gonophore, in lacking spines on the colony, and in having two types of gastrozooids. Torrey (1902) originally described H. milleri from Monterey Bay, California, and reported only one orange egg per gonophore. Mills and Miller (1978) also reported Hydractinia milleri with one egg. Clavactinia sp. is common on rock walls in the tide pool, and on rockwalls and overhangs in sheltered spots exposed during tides below the 0 level or chart datum (in Canadian tide and current tables 1984-1995). A description of this species is in preparation, together with a revision of the Hydractiniidae of the British Columbia coast (Brinckmann-Voss, unpublished data).
. Ecological remarks: Although tide pools have
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been studied frequently in different parts Of the world, little research has been published about them. Most work on tide pools has involved studies of algae and their reaction to changing salinity, temperature, desiccation, sometimes in comparison to open waters (Doty, 1957; Lewis, 1964; Carefoot, 1977; Newell, 1979; Thomas, 1983). More detailed investigation on fauna and flora of tidepools was reported by Stephenson et al. (1934), Pyefinch (1943), and Emson (1986), but there is very little information on hydroids in such pools. This is probably because the hydroid fauna of the intertidat zones – except for the infralittoral fringe (Stephenson and Stephenson, 1972; Carefoot, 1977; Kozloff, 1983; Calder, 1991 a,b) – is rather limited, as papers on intertidal zonation show (e.g. Southward, 1958; Ricketts and Calvin, 1968). Cornelius (1988) listed the hydroid fauna of tide pools at Holme next the Sea (U.K.), but in that case the hydroids were swept in from offshore areas, and were not autochthonous to the pool.
Some of the references cited above may help explain the diversity and abundance of hydroids in the Race Rocks tide pool:
1. Doty (1957) mentioned the abundance of organisms at the rim of tide pools, probably related to the “edge effect” reported by other ecologists (Carefoot, 1977). It may be assumed that the luxurious colonies of Phialella sp. and Sarsia eximia in the root system of the surfgrass immediately below the water surface of the pool could be related tothis edge effect, although its cause may be difficult to pinpoint.
2. Wedler (1975), studying comparable sites, reported of a greater abundance of hydroids in shaded than in sunny areas , where algae tend to dominate. (The same was observed by the author on the shaded and sunny side of floating docks). The qualitative and quantitative abundance of hydroids and relatively few algae in the pool may be influenced by this “shade ” effect, because the pool is shaded during emersion by the leaves of the surfgrass which form a canopy on its surface.
3. Lewis (1964) reported the influence of different velocities of tidal rapids on the intertidal fauna. From that work it may be inferred that the tidal rapids sweeping the tide pool area of Race Rocks
TABLE 2. – Seasonality of hydroids in the Race Rocks tide pool, March to October. Smaller and less abundant hydroid species, difficult to detect without taking material out of the pool, are marked (?); species with living hydranths absent were marked (-); those with hydranths present (+); those with gonads < colonies augmenting in size, > diminishing in size. For authors see table I play an important role in the establishment of the hydroid fauna there.
Species M A M J J A S O
Anthoathecatae
Clavidae
Rhizogeton ezoe se – – + – ++ ++ + +
Eudendriidae
Eudendrium sp. + + + + + + + +
Bougainvilliidae
Bougainvillia ramosa + + + + + + + +
Garveia annulata + +< ++ ++ ++ ++ ++ ++
Rhizorhagium roseum + + ++ ++ + ? ? ?
Rhysiidae
Rhysia fletcheri + ++ ++ ++ ++ ++ ++ ++
Hydractiniidae
Hydractinia armata – + < ++ ++ ++ ++ ++ ++
Clavactinia sp. + + ++ ++ ++ ++ ++ ++
Stylasteriidae
Stylantheca petrograpta + + + + + + + +
Acaulidae
Hataia parva ? ? ? + ? ? ? ?
Tubulariidae
Tubularia marina – – ++ ++ ++ ++ ++ ++
Hybocodon prolifer ++ ++ + – – – – –
Corynidae
Sarsia eximia + ++ ++ ++ >+ + + +
Leptothecatae
Calycellidae
Calycella syringe ? ? ++ ++ ++ ++ + +
Aequoreidae
Aequorea victoriae Phialellidae? ? ? ? + ? ? ?
Phiatella sp. < ++ ++ ++ ++ ++ ++ >
Haleciidae
Halecium pymaeum + + + ++ ++ ++ ++ ++
Hydrodendron sp. + + + + + + + +
Campanulariidae
Obelia dichotoma + <++ <++ ++ ++ ++ ++ ++
Campanularia ritteri + + ++ ++ ++ + + +
Campanularia volubilis + ++ ++ ++ ++ ++ ++ ++
Orthopyxis integra + <+ <++ <++ ++ ++ ++ ++
Laomedea exigua ? ? ? ? ? ++ ? ?
Clytia sp. ? ? ? + ++ ++ ++ ++
Sertulariidae
Symplectoscyphus turgidu s + + ++ ++ ++ ++ ++ ++
Abietinaria amphora ++ ++ ++ ++ ++ ++ ++ ++
Plumulariidae
Plumularia setacea + ++ ++ ++ ++ ++ ++ ++
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TABLE 3. – Hydroids identified from the infralittoral fringe and subtidal areas of Race Rocks, to a depth of 18 m, mostly west and north of the tide pool. Asterisks indicate species which were also found in the tide pool.
Anthoathecatae
Clavidae
Rhizogeton ezoense* Yamada, 1964
Rhizogeton nudus Broch, 1910
Eudendrium sp. (probably not same species as in tide pool) Bougainvilliidae
Bougainvillia sp. (not ramosa)
Garveia annulata* Nutting, 1901
Rhizorhagium roseum* M.Sars, 1864
Rhysiidae
Rhysia fletcheri* Brinckmann-Voss, Lickey and Mills, 1993 Hydractiniidae
Hydractinia laevispina Fraser, 1922
Clavactinia sp. *
Stylaster venustus (Verrill, 1870)
Tubularia sp. (less than 12 aboral tentacles)
Sarsia eximia* (Allman, 1859)
Sarsiaproducta (Wright, 1858)
Sarsia tubulosa (M.Sars, 1835)
Calycellidae
Haleciidae
Lafoeidae
Campanularia volubilis (Linnaeus, 1758)
Campanularia sp.
Clytia sp.
Obelia dichotoma* (Linnaeus, 1758)
Orthopyxis Integra
Abietinaria amphora* Nutting, 1904
Abietinaria greenei (Murray, 1860)
Abietinaria anguina (Trask, 1857)
Hydrallmania distans Nutting, 1899
Symplectoscyphus turgidus* (Trask, 1857)
Symplectoscyphus sp. tricuspidatus? (Alder, 1856)
Thuiaria sp.
Plumulariidae
Plumularia setacea*(Linnaeus, 1758)
Plumularia lagenifera Allman, 1885
Kirchenpaueriidae
Kirchenpaueria plumularoides (Clark, 1876)
Work on seasonality of hydroids has been done in different marine environments and climates (Riedl, 1959; Bouillon, 1975; Wedler, 1975; Boero and Fresi, 1986; Brinckmann-Voss, 1987; Calder, 1990; Garcia-Rubies, 1987,1992). Seasonal changes in the Race Rocks tide pool are most evident from late fall to spring – mainly on the species near the surface, when a marked regression occurs in numerous species. This regression is most likely caused by dilution of surface salinities during rain storms in the low winter tides (Carefoot, 1977; Thomas, 1983).
ACKNOWLEDGEMENTS
Research for this paper would not have been possible without the help of Garry Fletcher (senior biologist), Theo Dombrowsky and students of the Lester Pearson College of the Pacific (Metchosin, B.C., Canada). I thank them and the administration of the College for their help. Garry Fletcher introduced me to the tide pool on Race Rocks, instructed his students in searches for hydroids by diving, and made numerous collections by diving himself. Joan and Charles Redhead, former lighthouse keepers at Race Rocks, allowed me to stay at their lighthouse residence for several days during low tide periods, which allowed me to go back to the tide pool and check details during the same low tide period. I acknowledge their hospitality and help. Dale Calder (Royal Ontario Museum, Toronto, Canada) helped with this paper from its early stages through numerous discussions, advice and reviews, for which I am very thankful. I thank Paul Cornelius ( Natural History Museum, London, U.K.) for all help, especially with search for ecological literature, and I thank Stephen Cairns (National Museum of Natural History, Washington, U.S.A.) for identifying the Stylasteridae.
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PLEASE NOTE: THIS VERSION HAS BEEN SCANNED BY OPTICAL CHARACTER RECOGNITION. MOST HAS BEEN CORRECTED BUT IT MAY STILL HAVE A FEW ERRORS. -GF
REFERENCES
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Antsulevich, A. and W. Vervoort. – 1993. Some little known species of hydroids (Cnidaria: Hydrozoa: Lafoeidae) and description of Papillionella pterophora gen. nov. spec. nov. Zool. Meded. 67: 431-443.
Boero, F. 1987. – Life cycles of Phialella zappai n.sp., Phialella fragilis and Phialella sp. (Cnidaria, Leptomedusae,Phialellidae) from central California. J. nat. Hist. 21: 265-480.
Boero, F. and E.Fresi. – 1986. Zonation and evolution of a rocky bottom hydroid community. P.S.N.I.-Mar. Ecol. 7:123-150.
Bouillon, J. – 1975. Sur la reproduction et 1’6cologie de Paracoryne huvei Picard (Tubularoidea-Athecata-Hydrozoa- Cnidaria). Arch. Biol., 86:45-96.
Brinckrnann-Voss, A.- 1983. British Columbia marine faunistic report on the Hydrozoa, part 2 Hydroids. Canadian Technical Rep.of Fish. Aquat Sci, 1185: 1-20.
Brinckmann-Voss, A. – 1987. Seasonal distribution of hydromedusa (Cnidaria, Hydrozoa) from the Gulf of Naples and vicinity, with observation on sexual and asexual reproduction in some species. In: J. Bouillon, T. Boero, F. Cicogna and P.F.S. Cornelius (eds.) Modern Trends in the Systemtics, Ecology, and Evolution of Hydroids and Hydromedusae, pp. 133-141. Clarendon Press, Oxford.
Brinckmann-Voss, A. – 1988. Sarsia cliffordi n.sp. (Cnidaria, Hydfozoa, Anthomedusn) from British Columbia with distribution records and evaluation of related species. Can. J. Zool. 67: 685-691.
Brinckmann-Voss, A., D.M. Lickey, and CF. Mills. – 1993. Rhysia fletcheri (Cnidaria, Hydrozoa, Rhysiidae) a new species of colonial hydroids from Vancouver Island (British Columbia, Canada) and the San Juan Archipelago (Washington, U.S.A.). Can. J. Zool. 71: 401-406.
Broch, H. – 1909. Die Hydroiden der arktischen Meere. Faun Arctica 5: 129-247.
Calder, DR. – 1990 . Seasonal cycles of activity and inactivity to some hydroids from Virginia and South Carolina, U.S.A. Can.J. Zool. 68: 442-450.
Calder, DR. – 1991 a. Associations between hydroid species assemblages and substrate types in the mangal at Twin Cays, Belize. Can. J. Zool. 69:2067-2074.
Calder,D.R. 1991 b.Vertical zonation of the hydroid Dynamena crisioides ( Hydrozoa, Sertulaiiiidae) in a mangrove ecosystem at Twin Cays,.Belize. Can. J. Zool. 69: 2993 2999.
Canadian Tide and Current Tables, Volume 5, Juan de Fuca Strait and Strait of Georgia.- 1984-95. Dpt. Fish. Oceans, Ottawa, Canada.
Carefoot, T. – 1977. Pacific Seashores. J.J. Douglas Ltd, Vancouver.
Clark, S. F. – 1876. The hydroids of the Pacific coast of the United States, south of Vancouver Island. With a report on on those in the museum of Yale College. Trans Connecticut Acad Arts Set., 3: 249-264.
Clark, S. F. – 1877. Repon on the hydroids collected on the coast of Alaska and the Aleutian Islands, by W. H. Dall, U. S. Coast Survey, and party, from 1871 to 1874 inclusive Proc. Acad. Nat. Sci. Philadelphia 1876: 209-238.
Cornelius, P.F.S. 1988. Hydroid collection from intertidal pools at Holme next the Sea, Norfolk. Trans. Norfolk and Norwich Field Soc., 28: 72 78.
Cornelius, P.F.S. – 1992. Medusa loss in leptolid Hydrozoa (Cnidaria), hydmid rafting, and abbreviated life-cycles among their mmote-island faunae: an interim review. Sci. Mar. 56: 245-261.
Doty, M.S. – 1957. Rocky Intertidal Surfaces. Geol.Soc. Ame. Mem. 67: 535-585.
Emson,R.H. 1986.Life history patterns in rock pool animals.in: P.G.Moore and R.Seed (eds), The Ecology of Rocky Coasts. pp. 220-222. Columbia University Press, New York.
Fraser, C.M. – 1913. Hydroids from Vancouver Island and Nova Scotia. Bull. Victoria Mem. Mus. :147-188.
Fraser,C.M. 1937.Hydroids of thePacificCoast ofCanada and the United States. University of Toronto Press, Tomnto.
Garcia Rubies, A. – 1987. Distribution of epiphytic hydroids on Posidonia sea gmss. In: J. Bouillon, T. Boero , F. Cicogna and P.F.S. Cornelius (eds.) Modern Trends in the Systematics, Ecology, and Evolution of Hydroids and Hydromedusae, pp. 143-155. Clarendon Press, Oxford.
Garcia Rubies, A. – 1992. Habitat differentiation among epiphytic hydroids of the smgms Posidonia Oeanica from the Medes islands (NE Catalonia, Spain). Sci.Mar. 56: 263-267.
Henkel, I. – 1906. A study of tide-pools on the west coast of Vancouver Island. Postelsia 2:277-304.
Hirai E. and M. Yamada. – 1965. On a new athecate hydroid Hataia parva – n. gen., n. so. Bull. Mar. Biol. Stn. Asamuchi, .12: 59-62.
Kozloff, EN. – 1983. Seashore Life of the northern Pacific coast, rev. edition. Douglas and McIntyre, Vancouver.
Kramp, P.L. – 1959. The Hydromedusn of the Atlantic Ocem and Adjacent Waters. Dana Rep. 46: 1-283.
Kramp, P.L. – 1965. The Hydmmedusae of the Pacific and Indian Oceans, 1. Dana Rep. 68: 1-162.
Kramp, P.L. – 1968. The Hy&medusae of the Pacific and Indian Oceans, 11, III. Dana Rep. 72: 1-200.
Lewis, JR. – 1964. The Ecology of the rocky shores. ‘The English University Press, London.
Millard, N.A.H. – 1975. Monograph of the Hydroida of Southern Africa. Ann. S. Afri. Mus. 68: 1-513.
Mills, C. and R. Miller. – 1987. Hyroid polyps. In: Kozloff, E.N. (ed), Marine Invertebrates of the Pacific Northwest. pp. 44-62 Univ. Washington Press, Seattle.
Morris, R.H., Abbott, D.P, and Haderlie, E.C. – 1980. Intertidal Invertebrates of California. Stanford University Press, Stanford, California.
Naumov, D.V. 1960. Hydroids and Hydrowdusae of the USSR pan I-VI. English translation of original Russian in Israel Program for Scientific Translation , Jerusalem 1969 cat. no. 5108.
Newell, RC. – 1979. Biology of Intertidal Animals. Marine Ecological Surveys Ltd., Famshm, Kent.
Nutting, C.C. – 1900-1915. American hydroids, part 1-3. Smithsonian Institution, United States National Museum, Special Bulletin.
Paine, R.T. – 1994. Marine Rocky Shores and Commnity Ecology: An Experiwntalist’s Perspective. Excellence in Ecology:4. Ecology Institue, Oldendort/Luhe.
Pyefinch, K.A. – 1943.The interlidal ecology of Bardsey Island, North Wales , with special reference to the m-colonisation of rock surfaces, and the rock pool environment. J. Anim.Ecol. 12:82 108
Race Rocks Ecological Reserves #97. Publications List. B.C Parks, Ecological Reserves Office, 800-2 Johnsen Street, Victoria, B.C. V8V I X4 Canada.
Ricketts, E.F. and J. Calvin. 1968. Between Pacific Tides, 4th. ed., revised by J.W. Hedgpeth. Stanford Univ. Press, Stanford.
Riedl,R. – 1959. Die Hydroiden des Golfes von Neapel und ihr Anteil and der Fauna unterseeischer H6hlen. Ergebnisse der osterreichischen Tyrrhenia Expedition 1952 Teil 16. Pubbl. Stn. Zool. Napoli. 30 ( Suppl.) :589-755.
Southward, A.J. – 1958. The Zonation of Plants and Animals m Rocky Sea Shares. Biol-R”., Cambridge Phil. Soc. 33: 137-177.
Stephenson, T.A. and A. Stephenson. – 1972. Life between Tidemarks on Rocky Shores. W.H. Freeman and Company, San Francisco.
Stephenson,T.A., Zmnd, A. and J. Eym. – 1934.The liberation and ufilisation of oxygen by the population of rock pools. J. Exp. Biol. II: 162-172.
Thomas, M.L.H. – 1983. Marine and coastal systems of the Quoddy region, New Bmnswick, Canada. Can. Spe. Publ. Fish. Aqua. Sci. 64: 1-306.
Tokioka,T. – 1963. Supposed effects of the cold weather of the winter 1962-63 upon the intertidal fauna of the vicinity of Seto. Publ. Seto Mar. Lab. 9(2) :415-437.
Torrey, H.B. – 1902. The Hydroids of the Pacific Coast of North America with special reference to the species in the collection of the University of California. Univ. Calif. Public. Zool. 1: 1-104.
Wedler, E. – 1975. Okologische Untmuchungen an Hydroiden des Felslitorals von Santa Marta (Kolumbien). Heigolinder wiss. Meeresunters. 27: 324-363.
Yamada, M. – 1959. Hydroid fauna of Japan and its adjacent water. Publ. Akkeshi Mar. Biol. Star. 9: 1-101.
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SCI. MAR., 60 (1): 89-97
SCIENTIA MARINA 1996 ADVANCES IN HYDROZOAN BIOLOGY, S. PIRAINO, F. BOERO, J. BOUILLON, P.F.S. CORNELIUS and J.M. GILI (eds.)
A. BRINCKMANN-VOSS
Department of Invertebrate Zoology, Royal Ontario Museum, 100 Queen’s Park, Toronto, Ontario M5S 2C6, Canada.
Mailing address: P. 0. Box 653, Sooke, British Columbia VOS 1NO, Canada
see this link for images of hydroids studied in this paper: https://www.racerocks.ca/tag/hydroid/
See this link for images of Tidepool # 6 “Anita’a Pool”
*Received November 29, 1994, Accepted October 20, 1995
SUMMARY: An assemblage of 27 hydroid species was reported from a tide pool in the lower rocky intertidal zone, and compared with 42 hydroids of the adjacent subtidal region. Location of hydroids within the pool, seasonal occurrence, growth and sexual maturity were tabulated, and some systematic aspects discussed . Possible causes of hydroid species diversity were considered, including location of the tide pool in an area of tidal rapids, and shading by surfgrass and rock cliffs during low tide.
Key words: tide pools, hydroids, seasonality, Pacific coast.
INTRODUCTION
Invertebrate species diversity is high around Race Rocks (48′ 18′ N, 123′ 32′ E), an archipelago in the Strait of Juan de Fuca between Vancouver Island, Canada, and Washington state, USA. (Fig.1,2). Although publications of marine invertebrates are available for the areas to the east and west of Race Rocks (Henkel, 1906; Fraser, 1913; Kozloff, 1983), information about invertebrates from Race Rocks is mostly limited to personal observations or unpublished reports: P. Breen, Pacific Biological Station Nanaimo, Dpt.Fisheries and Oceans; P. Lambert, curator of invertebrates, Royal British Columbia Museum; Garry Fletcher and student essays from Lester Pearson College of the Pacific: in Race Rocks Ecological reserves #97 publications list 1988-1994). Because of its rich biota, the area is now protected as an ecological reserve. Research on hydroids there, started in 1984, continues today by permit.
Taxonomic investigations have been published previously to characterize some of the hydroid species mainly from a tide pool on the west side of Great” (great is ommitted trom here on) Race Rocks (Brinck-mann-Voss 1988; Brinckmann-Voss et al., 1993) . However, information about the cornpositon and distribution of hydroid species in the pool is lacking, as is a comparison of its hydroid fauna with that of the surrounding intertidal and adjacent subtidal shelf.
The purpose of this paper is, therefore, to provide information on the hydroids of a cold temperate tide pool with regard to seasonal occurrence, growth and regression, and reproductive periodicities. This research is intended as essentially a faunal study rather than a dedicated ecological work employing methods and analysis such as described for rocky shores by Paine (1994).
DESCRIPTION OF STUDY AREA
The study area may be classified as protected outer coast, the main island of Race Rocks being protected by surrounding rocks and reefs . The west and north sides of the island are swept by very swift tidal rapids with a maximum velocity of 3 m /s (Fig.2). The average maximum velocity for the first half of June 1995 , which included a neap and leap tide, was calculated at 2.7 m/s (Canadian Tide and Current Tables, 1995).
The tide pool studied here is located on the west side of the island in the low intertidal zone in the middle of the Pseudobalanus cariosus – Mytilus californianus – Pollicipes polymerus belt (Lewis, 1964; Ricketts and Calvin, 1968; Carefoot, 1977). It may be classified as “Ic” after the pool classification summarized by Thomas (1983). The pool surface emerges at 1.5 m above 0 tide level (0 represents the chart datum in Canadian Tide and Current Tables) (Figs.3,5).
FIG. 1. Map of southwestern British Columbia,with location of the Race Rocks archipelago,
FiG. 2. – Island of (Great) Race Rocks, with location of the tide pool As: A .Opposing arrows: area of very strong tidal currents, changing direction in ebb and flood tide.
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FIG. 3. – December tidal curve of Race Rocks (Victoria) area…… emersion period of tide pool (modified from Canadian Tide and Current Tables 1992).
Emersion of the pool surface is most obvious at leap tides. Although the pool may be exposed even at neap tides, waves and swells keep it awash, especially in stormy winter weather. During the emersion periods at leap tides, the pool does not drain and its water level changes are minimal. It is situated between a high cliff on the island side and a lower cliff toward the open sea. These two cliffs join at the north and south sides of the pool, thus forming a deep trough . Once emersed the pool is about 8m by 1.5m, slightly less wide in its northern part, with a maximum depth of 0.8m (Fig.4). It narrows in the middle with an exposed rock creating a small island (Fig.5). During incoming tide this is the first area to be flooded.
The surface temperature of the sea around Race Rocks varies during the year between 7 degrees C and 12 degrees C. Contrary to conditions in a shallow pool (without hydroids) 2m higher in the same area, surface and bottom temperatures in the lower and deeper pool, abundant with hydroids, scarcely differ from the sea temperature. Only during summer low tides, when the sun reaches the pool during the second third of the emersion period, are surface temperatures higher (2’C, rarely 42C )than the bottom temperatures or in the surrounding sea. Water temperatures were checked only February to October, because of the pool’s relative inaccessability in winter.
Unlike in the higher pool, salinities in the pool correspond with that of the adjacent sea (29-30%o, measurements provided partly by Garry Fletcher) from February to October.
No measurements of salinity and temperature were taken from November to January. However, the state of the surfgrass (Phyllospadix scouleri) lining the upper rim of the pool indicated that heavy winter rains in combination with low temperatures (Tokioka, 1963) impact the intertidal environment, including the rock pool. Lewis (1964), Carefoot (1977), and Thomas (1983) report on similar destructive effects of winter rains. The study area also encompassed the rocky infralittoral and subtidal, extending from 0-18m depth, to a distance of about 50 m from the shore around Race Rocks.
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MATERIAL AND METHODS
Collections of hydroids from the tide pool were made from March to October, over a period from 1984 to 1994.
Hydroid specimens were returned live to the laboratory, where they were examined and some photographed. Many were cultured to establish their identity, especially when specimens were collected in the hydrorhiza stage only. Species, depth and location of the hydroids were mapped on a diagram on the site.
Samples from the sublittoral shelf were taken by divers. The samples that were collected included both hydroids and a variety of bottom material, such as kelp holdfasts, barnacles, and mussels. These substrates were examined for small hydroids in the laboratory.
RESULTS
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FiG. 5. – Cross-section of tide pool at area of rock in center of pool. A: High water of high spring tide. B: Emersion level of tide PWI. C: Lower low water of spring tide. A to C represent the intertidalregion. S: Surface of tide pool at 1.5 m tide level and lower tides. P: phyllospadix scouleir belt, located 1.5 m higher in the pool than on the open shore, where it can be found at the border between the intertidal and subtidal, marked as C
Except for one hydroid species (Rhizogeton nudus) among the stalks of Pollicipes polymerus, no hydroids were found in the intertidal outside the pool between pool and infralitioral fringe.
Species composition of the pool and of adjacent subtidal regions was similar, with a few notable exceptions: luxurious colonies ofSarsia eximia and Phialella sp. occurred on the rhizomes of Phyllospadix sculeri (Zosteraceae, Angiospermeae) lining the rim of the rock pool, but these species were less abundant in the Phyllospadix scouleri belt of the infralittoral of the open coast, (for location ofPhyllospadix scouleri see Fig.5). Conversely, larger species of the Sertulariidae were more diverse and abundant subtidally than in thepool. Plumularia setacea was common in the pool but less so subtidally, whereas Plumulara lagenifera was not found in the pool, but was abundant subtidally.
Hydroids of the tide pool were referrable to three groups. Group A showed marked seasonal cycles of activity and regression, with hydroid colonies represented during a dormant phase by hydrorhizae only. Species of group B were present periodically as small colonies, typically in early spring, and then enlarged during late spring and summer. Group C included species in which the activity patterns and colony sizes remained relatively unchanged throughout the year.
Included in group A was Hybocodon prolifer, abundant and fertile in late winter and spring, but reduced only to stolons in summer and fall. Sarsia eximia and Phialelia sp. (described by Boero 1987, but not named), living among the rhizomes of Phyllospadix scouleriplants (Zosteraceae), were reduced to hydrorhiza or to small colonies with a few sterile hydranths in late winter and spring. Both species occurred as large and fertile colonies in summer spreading occasionally onto the outer dead leaf sheadi of Phyllospadix or onto the surrounding rocks.
Peak reproduction was in June and July for Sarsia eximia and in September for Phialella sp.
Species of group B (e.g. Orthopyxis integral Obelia dichotoma, Garveia annulata, and Clavactinia sp.) were present as small patches in early spring. By late summer their colonies had enlarged and stolonal species covered wide areas on the rock walls of the pool. InClavactinia sp., reduction and expansion of the same colony was observed over a period of two years.
Species assigned to group C changed little in colony size during the year. These included representatives of the families Stylasteridae, Plumulariidae, and Sertulariidae. This may be related to their morphology, as their hydranths are more protected through the extensive perisarc of the colony, than species of group A and B.
DISCUSSION
Systematics: The taxonomy of hydroids from the northeastern Pacific, and especially of the Leptothecatae (terminology after Cornelius, 1992), is inadequately known. A large number of species has been reported from the area by Fraser (1913,1937), and before him by authors including Nutting (190015), Torrey (1902), and Clark (1876, 1877). However, many specimens collected from Race Rocks and adjacent areas do not correspond with descriptions of such species, a problem discussed by Brinckmann-Voss (1983) and Mills and Miller (1987). Detailed monographic revision is therefore needed from hydroids of the northeast Pacific. Comparisons are warranted with the hydroid fauna of the northwest Pacific (Yamada, 1959; Naumov, 1960; Antsulevich, 1992; Antsulevich and Vervoort, 1993), and with that of the circumpolar Arctic (Broch, 1909), as done by Kramp (1959, 1965, 1968) for the hydromedusae.
Accordingly, several species in this paper were identified only to the genus level (Tables 1-3). Work is currently underway on the Plumulariidae from Race Rocks and elsewhere on the British Columbia coast (Brinckmann-Voss and Calder, unpublish data). Changes of family and genus were made of two species of Anthoathecatac. Hataia parva Hirai and Yamada 1965, previously assigned to the Clavidae, is assigned here to the Acaulidae. Features described in the original (Hirai and Yamada, 1965) and in recent (Yamada and Kubota, 1989) work on the species as to its solitary nature, mode of asexual reproduction, and presence of stenoteles, justified placing Hataia near the genus Acaulis Stimpson, family Acaulidae. A species identified as Hydractinia milleriTorrey 1902 in Morris et al. (1980) is tentatively referred to the genus Clavactinia Thomely as Clavactinia sp. because its gastrozooids have several whorls of tentacles (Millard, 1975). The species listed in Morris, Abbott and Haderlie and found in the Race Rocks area is distinguished from H. milleri Torrey in
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TABLE 1. Distribution of hydroids in the Race Rocks tide pool. Numbers refer to locations in the pool (as in Fig. 4).
Species
Anthoathecatae
Clavidae
Rhizogeton ezoense Yamada,1964
Eudendriidae
Eudendrium sp.
Bougainvilliidae
Bougainvillia ramosa (van Beneden , I 844)
Garveia annulata Nutting, 1901
Rhizorhagium roseum M.Sars, 1874
Rhysiidae
Rhysia fletcheri Brinckmann-Voss, Lickey, Mills, 1993
Hydractiniidae
Hydractinia armatata Fraser, 1940
Clavactinia sp.
Stylasteridae
Hataia parva Hirai and Yamada, 1 965
Tubulariidae
Tubularia marina Toney, 1902
Hybocodon prolifer L.Agassiz, 1 862
Corynidae
Sarsia eximia (Allman,1859) (on rhizomes of Phyllospadix)
Leptothecatae
Calycellidae
Calycella syringa (Linnaeus, 1767)
Aequoreidae
Aequorea victoriae (Murbach and Shearer, 1902)
Phialellidae
Phialella sp. (on rhizomes of Phyllospadix)
Haleciidae
Campanularidae
Canpanularia volubilis (Linnaeus,1758)
Laomedea exiguae M.Sars,1857
Orthopyxis integra (Mugillivray,1942)
Clytia sp. (on Mytilus)
Sertulariidae
Abietinaria amphora Nutting, 1904
Plumulariidae
having several purple eggs per gonophore, in lacking spines on the colony, and in having two types of gastrozooids. Torrey (1902) originally described H. milleri from Monterey Bay, California, and reported only one orange egg per gonophore. Mills and Miller (1978) also reported Hydractinia milleri with one egg. Clavactinia sp. is common on rock walls in the tide pool, and on rockwalls and overhangs in sheltered spots exposed during tides below the 0 level or chart datum (in Canadian tide and current tables 1984-1995). A description of this species is in preparation, together with a revision of the Hydractiniidae of the British Columbia coast (Brinckmann-Voss, unpublished data).
. Ecological remarks:
Although tide pools have
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been studied frequently in different parts Of the world, little research has been published about them. Most work on tide pools has involved studies of algae and their reaction to changing salinity, temperature, desiccation, sometimes in comparison to open waters (Doty, 1957; Lewis, 1964; Carefoot, 1977; Newell, 1979; Thomas, 1983). More detailed investigation on fauna and flora of tidepools was reported by Stephenson et al. (1934), Pyefinch (1943), and Emson (1986), but there is very little information on hydroids in such pools. This is probably because the hydroid fauna of the intertidat zones – except for the infralittoral fringe (Stephenson and Stephenson, 1972; Carefoot, 1977; Kozloff, 1983; Calder, 1991 a,b) – is rather limited, as papers
on intertidal zonation show (e.g. Southward, 1958; Ricketts and Calvin, 1968).
Cornelius (1988) listed the hydroid fauna of tide pools at Holme next the Sea (U.K.), but in that case the hydroids were swept in from offshore areas, and were not autochthonous to the pool.
Some of the references cited above may help explain the diversity and abundance of hydroids in the Race Rocks tide pool:
1. Doty (1957) mentioned the abundance of organisms at the rim of tide pools, probably related to the “edge effect” reported by other ecologists (Carefoot, 1977). It may be assumed that the luxurious colonies of Phialella sp. and Sarsia eximia in the root system of the surfgrass immediately below the water surface of the pool could be related to
this edge effect, although its cause may be difficult to pinpoint.
2. Wedler (1975), studying comparable sites, reported of a greater abundance of hydroids in shaded than in sunny areas , where algae tend to dominate. (The same was observed by the author on the shaded and sunny side of floating docks). The qualitative and quantitative abundance of hydroids and relatively few algae in the pool may be influenced by this “shade ” effect, because the pool is shaded during emersion by the leaves of the surfgrass which form a canopy on its surface.
3. Lewis (1964) reported the influence of different velocities of tidal rapids on the intertidal fauna. From that work it may be inferred that the tidal rapids sweeping the tide pool area of Race Rocks
TABLE 2. – Seasonality of hydroids in the Race Rocks tide pool, March to October. Smaller and less abundant hydroid species, difficult to detect without taking material out of the pool, are marked (?); species with living hydranths absent were marked (-); those with hydranths present (+); those with gonads < colonies augmenting in size, > diminishing in size. For authors see table I
Species M A M J J A S O
Anthoathecatae
Clavidae
Rhizogeton ezoe se – – + – ++ ++ + +
Eudendriidae
Eudendrium sp. + + + + + + + +
Bougainvilliidae
Bougainvillia ramosa + + + + + + + +
Garveia annulata + +< ++ ++ ++ ++ ++ ++
Rhizorhagium roseum + + ++ ++ + ? ? ?
Rhysiidae
Rhysiafletcheri + ++ ++ ++ ++ ++ ++ ++
Hydractiniidae
Hydractinia armata – + < ++ ++ ++ ++ ++ ++
Clavactinia sp. + + ++ ++ ++ ++ ++ ++
Stylasteriidae
Stylantheca petrograpta + + + + + + + +
Acaulidae
Hataia parva ? ? ? + ? ? ? ?
Tubulariidae
Tubularia marina – – ++ ++ ++ ++ ++ ++
Hybocodon prolifer ++ ++ + – – – – –
Corynidae
Sarsia eximia + ++ ++ ++ >+ + + +
Leptothecatae
Calycellidae
Calycella syringe ? ? ++ ++ ++ ++ + +
Aequoreidae
Aequorea victoriae Phialellidae? ? ? ? + ? ? ?
Phiatella sp. < ++ ++ ++ ++ ++ ++ >
Haleciidae
Halecium pymaeum + + + ++ ++ ++ ++ ++
Hydrodendron sp. + + + + + + + +
Campanulariidae
Obelia dichotoma + <++ <++ ++ ++ ++ ++ ++
Campanularia ritteri + + ++ ++ ++ + + +
Campanularia volubilis + ++ ++ ++ ++ ++ ++ ++
Orthopyxis integra + <+ <++ <++ ++ ++ ++ ++
Laomedea exigua ? ? ? ? ? ++ ? ?
Clytia sp. ? ? ? + ++ ++ ++ ++
Sertulariidae
Symplectoscyphus turgidu s + + ++ ++ ++ ++ ++ ++
Abietinaria amphora ++ ++ ++ ++ ++ ++ ++ ++
Plumulariidae
Plumularia setacea + ++ ++ ++ ++ ++ ++ ++
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TABLE 3. – Hydroids identified from the infralittoral fringe and subtidal areas of Race Rocks, to a depth of 18 m, mostly west and north of the tide pool. Asterisks indicate species which were also found in the tide pool.
Anthoathecatae
Clavidae
Rhizogeton nudus Broch, 1910
Eudendriidae
Eudendrium sp. (probably not same species as in tide pool) Bougainvilliidae
Bougainvillia sp. (not ramosa)
Garveia annulata* Nutting, 1901
Rhizorhagium roseum* M.Sars, 1864
Rhysiidae
Rhysiafletcheri* Brinckmann-Voss, Lickey and Mills, 1993 Hydractiniidae
Clavactinia sp. *
Stylasteridae
Tubulariidae
Corynidae
Sarsiaproducta (Wright, 1858)
Sarsia tubulosa (M.Sars, 1835)
Leptothecatae
Calycellidae
Haleciidae
Lafoeidae
Campanularia sp.
Clytia sp.
Obelia dichotoma* (Linnaeus, 1758)
Orthopyxis Integra
Sertulariidae
Abietinaria greenei (Murray, 1860)
Abietinaria anguina (Trask, 1857)
Hydrallmania distans Nutting, 1899
Symplectoscyphus turgidus* (Trask, 1857)
Symplectoscyphus sp. tricuspidatus? (Alder, 1856)
Thuiaria sp.
Aglaopheniidae
Plumulariidae
Plumularia setacea*(Linnaeus, 1758)
Plumularia lagenifera Allman, 1885
Kirchenpaueriidae
Kirchenpaueria plumularoides (Clark, 1876)
play an important role in the establishment of the hydroid fauna there.
Work on seasonality of hydroids has been done in different marine environments and climates (Riedl, 1959; Bouillon, 1975; Wedler, 1975; Boero and Fresi, 1986; Brinckmann-Voss, 1987; Calder, 1990; Garcia-Rubies, 1987,1992). Seasonal changes in the Race Rocks tide pool are most evident from late fall to spring – mainly on the species near the surface, when a marked regression occurs in numerous species. This regression is most likely caused by dilution of surface salinities during rain storms in the low winter tides (Carefoot, 1977; Thomas, 1983).
ACKNOWLEDGEMENTS
Research for this paper would not have been possible without the help of Garry Fletcher (senior biologist), Theo Dombrowsky and students of the Lester Pearson College of the Pacific (Metchosin, B.C., Canada). I thank them and the administration of the College for their help. Garry Fletcher introduced me to the tide pool on Race Rocks, instructed his students in searches for hydroids by diving, and made numerous collections by diving himself. Joan and Charles Redhead, former lighthouse keepers at Race Rocks, allowed me to stay at their lighthouse residence for several days during low tide periods, which allowed me to go back to the tide pool and check details during the same low tide period. I acknowledge their hospitality and help. Dale Calder (Royal Ontario Museum, Toronto, Canada) helped with this paper from its early stages through numerous discussions, advice and reviews, for which I am very thankful. I thank Paul Cornelius ( Natural History Museum, London, U.K.) for all help, especially with search for ecological literature, and I thank Stephen Cairns (National Museum of Natural History, Washington, U.S.A.) for identifying the Stylasteridae.
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PLEASE NOTE: THIS VERSION HAS BEEN SCANNED BY OPTICAL CHARACTER RECOGNITION. MOST HAS BEEN CORRECTED BUT IT MAY STILL HAVE A FEW ERRORS. -GF
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Brinckmann-Voss, A., D.M. Lickey, and CF. Mills. – 1993. Rhysia fletcheri (Cnidaria, Hydrozoa, Rhysiidae) a new species of colonial hydroids from Vancouver Island (British Columbia, Canada) and the San Juan Archipelago (Washington, U.S.A.). Can. J. Zool. 71: 401-406.
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| A0 | refers to the first site to be added to this website |
| 05 | refers to the peg location ( we have 15 such locations permanently identified at the Race Rocks Ecological Reserve.) |
| 03 | refers to the third transect entered from this location. |
| 01 | refers to the first quadrat picture that you can access on this photographic strip. |
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Return to the Contents page for Environmental modelling with Transects..
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Where:
| A0 | refers to the first site to be added to this website |
| 05 | refers to the peg location ( we have 15 such locations permanently identified at the Race Rocks Ecological Reserve.) |
| 03 | refers to the third transect entered from this location. |
| 01 | refers to the first quadrat picture that you can access on this photographic strip.
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Elevation 3.7 metres
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See Transect A0050102
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Permission for reproduction of this paper has been granted by the Canadian Journal of Zoology and the Author. Color images have been taken by A.B.V. and D.M.L. and were added to this html document by G.Fletcher.
| p.401 , Vol 71, 1993 Rhysia fletcheri (Cnidaria, Hydrozoa, Rhysiidae), a new species of colonial hydroid from Vancouver Island (British Columbia, Canada) and the San Juan Archipelago (Washington, U.S.A.)A. BRINCKMANN-VOSS Department of lnvertebrate Zoology, Royal Ontario Museum, 100 Queen’s Park, Toronto, Ont., Canada M55 2C6And D. M. LICKEY AND C. E. MILLS, Friday Harbor laboratories, University of Washington, 620 University Road, Friday Harbor, WA 98250, U.S.A.Received February 28, 1992 Accepted September 17, 1992BRINCKMANN-VOSS, A., LICKEY, D. M., and MILLS, C. E. 1993. Rhysia fletcheri (Cnidaria, Hydrozoa, Rhysiidae), a new species of colonial hydroid from Vancouver Island (British Columbia, Canada) and the San Juan Archipelago (Washington, U.S.A.). Can. J. Zool. 71: 401-406.  A group of females A new species of colonial athecate hydroid, Rhysia fletcheri, is described from Vancouver Island, British Columbia Canada, and from Friday Harbor, Washington, U.S.A. Its relationship to Rhysia autumnalis Brinckmann from the Mediterranean and Rhysia halecii (Hickson and Gravely) from the Antarctic and Japan is discussed. Rhysia fletcheri differs from Rhysia autumnalis and Rhysia halecii in the gastrozooid having distinctive cnidocyst clusters on its hypostome and few, thick tentacles. Most of its female gonozooids have no tentacles. Colonies of R. fletcheriare without dactylozooids. The majority of R. fletcheri colonies are found growing on large barnacles or among the hydrorhiza of large thecate hydrozoans. Rhysia fletcheri occurs in relatively sheltered waters of the San Juan Islands and on the exposed rocky coast of southern Vancouver Island.  c. (a group of males.. relaxed)  b. -( group of males ..contracted.)
On trouvera ici la description d’un nouvelle espece d’hydroide colonial sans theque. Rhysia fletcheri, trouvee dans l’ile de Vancouver en Colombie-Britannique, Canada, et a Friday Harbor, Washington, Etats-Unis. Sa relation avec Rhysia autumnalis Brinckmann en Medlterrannee et Rhysia halecii (Hickson and Gravely), de l’Antarctique et du Japon, fait l’objet d’une discussion. Rhysia fletcheri differe des deux autres especes par la presence chez le gastrozooide de faisceaux tres particuliers de cnidocystes sur l’ hypostome et de tentacules epais et peu nombreux. La plupart des gonozooides femelles sont depourvus de tentacules. Les colonies de R. fletcheri ne comportent pas de dactylozooides. La majorite des colonies de R. Fletcheri crois sent sur les grosses balanes ou parmi les hydrorhizes des gros hydrozoaires a theque. Rhysia Fletcheri se trouve dans les eaux relativement protegees des iles San Juan et sur la cote rocheuse exposee du sud de l’ile de Vancouver. [Traduit par la redaction.] |
Introduction:Colonies of a hydroid species belonging to the genus Rhysia Brinckmann, 1965 were collected off Friday Harbor in Washington State, U.S.A., from 1972 to 1992. They were found in tide pools at Race Rocks, British Columbia, Canada, and from adjacent coastal regions of Vancouver Island between 1986 and 1992. The species is referable to the hydrozoan family Rhysiidae, and to the genusRhysia, in having gonads within the body wall along one side of the gonozooid. However, it differs from previously described species of the genus in having cnidocysts arranged in clusters on the hypostome of the gastrozooid, and in having fewer and thicker tentacles on the gastrozooid, and no dactylozooids. The purpose of this paper is to provide a systematic and ecological account of Rhysia fletcheri sp.nov. The species is compared with Rhysia autumnalis Brinckmann, 1965, type species of the genus Rhysia, and with Stylactis halecii Hickson and Gravely, 1907. The latter species has lateral gonads, as doR. autumnalis and R. fletcheri sp.nov., and is assigned here to the genus Rhysia as well.ETYMOL0GY: Rhysia fletcheri is named for Garry Fletcher, senior biologist at Pearson College and voluntary warden of the Ecological Reserve of Race Rocks, British Columbia, Canada, who was instrumental in establishing Race Rocks as an Ecological Reserve in 1980.
Material examined:  Growing on the valves of the barnacle Balanus nubilus , female and male colony .(.click on picture) . Top left, two females, below left gastrozooids: below right – male. Holotype: Friday Harbor, Washington, U.S.A., on Balanus nubilis attached to a tire on the side of floating docks at Friday Harbor Laboratories of the University of Washington, 0.5 m, 5 October 1984, female colony, National Museum of Natural History, Smithsonian Institution, Cat. No. USNM 73984. Paratypes: Race Rocks, British Columbia, Canada, on Semibalanus cariosus in tide pool, 0.5 m, 5 April 1990, male colony, Royal Ontario Museum Cat. No. ROMIZ B1164; Friday Harbor, Washington, on hydrorhiza of a thecate hydroid colony, 10-15 m, October 1972, female colony, Royal Ontario Museum Cat. No. ROMIZ B1165; Race Rocks, British Columbia, on Semibalanus cariosus in tide pool, 0.5 m, 15 June 1991, female and male colony, Royal British Columbia Museum Cat. No. RBCM 992-170-1. Further material is deposited in the Natural History Museum, London, England. Description: Hydroid colony stolonal, arising from a creeping and anastomosing hydrorhiza. Hydrorhiza thick (averaging 0.05 mm), covered with a very thin and often virtually invisible perisarc (Fig. 2a), giving rise to gastrozooids and gonozooids. Zooids inserting with hydrorhiza via a broad base and without a neck or stem (Figs. Ia, 2a); perisarcal collar absent around bases of zooids. Gastrozooids widely scattered, occurring singly or in a loose group. Gastrozooids extremely contractile, 0.3÷1.0 mm long, appearing columnar to barrel-shaped or like a contracted sea anemone if exposed to strong light (compare Figs. Ia and 4a). (Page 402)  Figure 1. Rhysia fletcheri, gastrozooid, relaxed, preserved. (a) Whole animal, (b) oral region. Scale bars =0.1 mm. Gastrozocid tentacles 4 – 10, filiform, in a single whorl, 0.08 – 0.10 mm thick depending on the degree of contraction, each with more than 30 endodermal cells, cnidocysts arranged in a more or less distinct spiral (Fig. lb). Hypostome round, surrounded by a circle of 4 or 5 cnidocyst clusters that do not develop into tentacles (Figs. 2e, 2f, 4a). Gonozooids often separated from gastrozooids by several millimetres, occurring in dense clusters (Figs. 3, 4}. Gonads developing internally on one side of gonozooid, without a gonophore (Figs. 4b, 4c). Female gonozooids up to 1.1 mm high when mature (Figs. 3a÷3d); hypostome round, provided with a cap of cnidocysts, not divided into separate clusters as in gastrozooid; mouth lacking; tentacles typically lacking; in gastrozooid; mouth lacking; tentacles typically lacking; immature female gonozooids, at a stage not more than 115 the height of a mature gonozooid, being recognizable as such in showing an egg on one side. Male gonozooids develop 3 or 4 oral tentacles, which are shorter and thinner than those of gas- trozooids, each tentacle has up to 10 endodermal cells and bears cnidocysts at the tip only, some with thickened tips(Figs. 2c, 4b) because of the presence of larger numbers of cnidocysts (this varies among colonies); hypostome of males round, more conical than in females, provided with evenly distributed cnidocysts, unlike the cnidocyst clusters typical of gastrozooids; mouth lacking. Male gonozooids with mature gonads sometimes exceeding gastrozooids in length, reaching a maximum of 1.5 mm. Dactylozooids absent. Gastrozooids and gonozooids pink to orange, due to the colour of the endoderm; tentacles and hypostomes milky white; eggs and planulae peach coloured; male gonads milky white in early stages, iridescent in later stages.
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By Robin W. Baird
Elephant Seals occur fairly frequently on -the B.C. coast, but few people recognize them when they do see them. Adult males only rarely come ashore, and while in the water animals of all ages and both sexes spend up to 90% of their time beneath the surface. Their behaviour while at the surface makes them very difficult to notice as well: at first glance they appear similar to a large, partially waterlogged log floating vertically at the surface (commonly termed a deadhead). Unlike real deadheads, which may bob up and down with waves or a swell, Elephant Seals just sink slowly out of sight after several minutes, and may not surface again for half an hour or more. In fact, the maximum recorded dive length (actually, for the similar southern Elephant Seal) is exactly two hours (Hindell et al. 1989), and they usually only surface for two to three minutes before repeating their dive. They do this day and night, for days, weeks and even months on end, even sleeping underwater. As well, they are generally solitary except during the breeding season, and only breed off the California and Mexican coasts.( now-2006, also at race Rocks)
Elephant Sea[, at Race Rocks. (Photo: Robin Baird)
Moulting occurs at different times throughout the year depending on the age and sex of the animal. Juvenile Elephants Seals (about 1.5 – 2 metres in length) moult in the spring. In B.C. this is the age class most frequently seen hauling out to moult.
Moulting in Elephant Seals not only involves losing the hair, but the entire outer layer of skin, often in great sheets, and frequently the animals suffer from skin infections, resulting in bleeding. These infections are usually of low level and do not typically seriously harm the animal. When Pinnipeds (seals, sea lions and walruses) come out of the water their eyes continuously water to keep them moist, an adaptation that protects their eyes but also contributes to their sick appearance.
Most people assume that Elephant Seals are much larger than the juveniles which typically haul out in this area, but at this stage they appear fairly similar to Harbour Seals. In fact, confusing juvenile Elephant Seals with Harbour Seals occurs frequently. Despite the fact
Elephant Seal, adult male. (Photo: P.J. Stacey)
that Elephant Seals can be approached closely by people on foot, have watering eyes, and due to their epidermal moult have skin that is literally falling off and sometimes infected, these are normal conditions and the animals are in reality quite healthy. There have been several occasions around Victoria in the last year where such Elephant Seals have been mistakenly identified as sick Harbour Seals and this has resulted in the inadvertent euthanization of the animals.
The differences between juvenile Elephant Seals and Harbour Seals are fairly obvious once you know what they are. Unlike Harbour Seals, Elephant Seals have no spots on the skin, rather they are a uniform greyish brown or yellowish colouration, although while moulting, their skin appears very patchy. The rather “swolled’ snout, and the horizontal crease just below the nostrils are characteristic of Elephant Seals, and a harbinger of the bulbous nose that comes with adulthood for the males. The hind flippers of Harbour Seals are relatively straight along the trailing edge, while Elephant Seals have a inverted U-shaped curve to the trailing edge of their hind flippers. Many of the animals are also tagged on the hind flippers, while very little work has been done in tagging Harbour Seals.
More accurate identification of Elephant Seals will both prevent the types of accidents mentioned above from occurring, and will assist research in terms of trying to monitor the numbers of Elephant Seals in the province. If population numbers in B.C. mimic the increase seen in their breeding range off California, Elephant Seals may become a more common sight off our coast. Such an increase should not worry those concerned with potential conflicts with fisheries, as the diet of the Elephant Seal consists mainly of species largely ignored commercially, such as Ratfish, Dogfish and other sharks, various species of skate, some squid, Cusk Eels, and occasionally deep water, slow swimming fish.
Records of Elephant Seals around southern Vancouver Island have been increasing in the last year, although it is not known if this is due to an actual increase in their presence, or just that more people are aware of the differences between Harbour Seals and Elephant Seals, and are reporting their presence.
We have been attempting to respond to most reports of hauled out Elephant Seals, or of 1arge sick Harbour Seals that you can walk right up to”. We try to check for tags, record age and if possible sex (not an easy task since you’d have to roll the distress.
Some animals are branded as well as tagged, although they lose the brand when they moult. Many are double tagged, with a different number on each tag, so both left and right hind flippers should be checked if an animal is found.
A summary of records of Elephant Seals in B.C., including information on their origin (for tagged individuals), is presently being compiled by Victoria resident Marcel Gijssen and others. Dr. Burney Le Boeuf is responsible for tagging many of the animals born near Ano Nuevo, a site in central California between Santa Cruz and San Francisco.
Anyone observing elephant seals in B.C. can assist with this project by reporting sightings to me at the following address:Department of Biological Sciences,Simon Fraser University, address now not applicable
References:
Hindell, M.A., Slipp, D.J., and Burton, H.R. 1989. Diving Be-haviour and Foraging Ranges of Southern Elephant Seals (Mirounga leonina) From Macquire Island. Page 29 in Abstracts of the Eighth Biennial Conference on the Biol ogy of Marine Mammals, December 1989, Pacific Grove.
6The Victoria Naturalist Vol. 47.2 (1990)
