CHAPTER 3 The Fouling Community

The term "fouling" is commonly employed to gation buoys of the Elbe (4). Hentschel listed distinguish the assemblages of animals and plants about 50 species from ships docking at Hamburg which grow on artificial structures from those oc- (3). Seventy-seven kinds of animals and plants curring on rocks, stones, and other natural objects. are listed from ships examined in United States Frequently its use is limited to situations in which waters by Visscher (11). the results of the growth may be considered harm- In order to make available the information on fuL. The concept of fouling is thus based on the the composition of fouling, a comprehensive list practical considerations which have indeed given has been prepared of species recorded from the the subject its importance rather than on any valid principal types of structure affected. This list is biological distinctions. Fouling is, however, a bio- presented in Chapter 10. It includes records from logical phenomenon. If it is to be dealt with ef- structures on which fouling gives rise to problems fectively from an engineering point of view, it is of some technical interest, i.e., ships, buoys, water important that the biological principles which de- conduits and pipe systems, wrecks, telegraph termine its development be understood. cables, rafts, floats, pontoons, and test panels. The. animals and plants which take part in Records from wharf piles, piers, quays, jetties, fouling are primarily the attached, or sessile, bridge abutments, and similar structures have forms which occur naturally in the shallower water been omitted. along the coast. Each of these is adapted to live The following general conclusions are based on successfully under some restricted set of environ- the analysis of this list. mental conditions which limit the particular Nearly 2,000 species of animals and plants have places, both on a geographical and local scale, been reported from fouling. The number of species where it may be found. The development of an representing each of the major groups of organ- assemblage of fouling organisms on any structure isms, listed in Table 1, includes 615 kinds of immersed in the sea depends on the ability of cer- plants and 1,361 varieties of animals. The list in- tain members of the natural population locally cludes 13 of the 17 commonly accepted phyla of present to live successfully in the new situations animals and all the major groups of marine Thalo- created by man. From the biological point of view, phytes. The four missing phyla of animals are the fouling is thus an accident, and of very recent Ctenophora, Chaetognatha, Nematoda, and Phor- ongin. onidea. The two former are pelagic organisms not The development of permanent and massive likely to occur in fouling. The Nematoda are com- growths depends on the ability of sessile forms to mon free living members of fouling communities, adhere firmly enough to avoid being washed away. but have escaped record because they are diffcult Many free living animals are found among such to identify. The Phoronidea contain very few sessile organisms. They are an integral part of the species, but may be recorded ultimately since fouling ,community and cannot be separated from they are sessile forms, partial to crevices in rocks. it on any reasonable grounds. Separation on the Although the number of species reported from basis of freedom of movement or firmness of at- fouling is large and is widely distributed among the tachment is diffcult, since some sessile forms like existing groups of organisms, it actually includes the mussel are able to cast off their anchorage and a very small proportion of the known marine move from place to place, while some motile species. The proportional representation among forms such as the chiton can cling to smooth sur- the different groups is also very unequal. These faces with a tenacity which resists the most violent facts are brought out by Table 2 in which the water movements. total numbers of known marine species are com- The organisms occurring in fouling have been pared with the numbers reported from fouling. It recorded frequently. A few attempts have been is only among five groups that the species known made to prepare lists of the species but these to foul make up more than 2 or 3 per cent of the have been limited to those found on particular recognized species. These are the Barnacles, structures. Kirchenpauer compiled a list of 84 spe- Tunicates, Hydroids, Marine Plants, and Bryozoa cies, ,the majority of them plants, from the navi- -all groups which are predominantly sessile and 37 38 MARINE FOULING AND ITS PREVENTION which contribute heavily to fouling. Certain other tered in fouling. Those reported most frequently sessile groups, such as the sponges and corals, from all types of structures are listed in Table 3. are recorded relatively infrequently from fouling. The frequency with which various species were . found on the ships examined by Hentschel (3) TABLE 1. Number of Species of the Various Groups and Visscher (11) is recorded in Table 4. Whidi are Reported from Fouling Total Plants 614 There is litte doubt that some differences exist Total Animals 1,344 Total List 1,958 TABLE 2. Comparison of the Total Number of Marine Species Plants Totals Assigned to Various Groups and the Number of Each Group B~~ria...... 37 Reported from Fouling. Estimated Totals for Animals from Fungi...... 14 Pratt (8), for Plants from ZoBell (12) Algae..Diatoms ...... 111 563 Total Marine Species %in Blue green 32 Group Species in Fouling Fouling Green 127 Goose barnacles 200 50 25.0 Brown 88 Acorn barnacles 300 60 20.0 Tunicates 700 116 16.6 R~ 2~ Hydroids 3,000 260 8.7 Animals Marine Plants 8,000 614 7.7 Protozoa...... Bryozoa 3,000 139 4.6 Mastigophora 5 99 N udibranchs 1,000 32 3.2 Foraminifera 43 Polychaetes 3,500 99 2.8 N emerteans 500 11 2.2 Other Sarcodina 3 Amphipods 3,000 60 2.0 Ciliata 39 Pycnogonids 400 8 2.0 Suctoria 9 . Pelecypods 9,000 115 Porifera...... 33 1.3 Coelenterata...... Anemones 1,000 12 1.2 Hydrozoa (Hydroids) 260 286 Sponges 3,000 33 1.1 Hydrocorallnae 1 Decapods 8,000 76 1.0 A1cgonaria 5 Isopods 3,000 24 0.8 Actinaria (Anemones) 12 Gastropods (other than 4,900 58 0.8 Madreporaria (True Corals) 8 Nudibranchs) Echinoderms 4,800 19 0.4 Platyhelminthes...... 12 Corals 2,500 8 Nemertea...... 11 0.3 Trochelminthes (Rotifers) ...... ~ 5 Bryozoa...... 139 TABLE 3. Nineteen Forms Cited More Than 12 Times From Brachiopoda...... 1 Annelida...... 108 Fouling, in Order of Frequency of Citation. Archiannelids 1 (Data from Fouling List, Chapter 10) Polychaeta Errantia 44 Number OJ Polychaeta Sedentaria (Tubeworm:s) 55 Form Group Citations Oligochaeta 4 M ytilus edulis Pelecypod Molluscs 34 Hirudinea (Leeches) 4 Bugiila neritina Bryozoa 24 Arthropoda...... 292 Copepoda 7 Balanus eburneus Acorn barnacles 23 Ostracoda 5 Balanus crenatus Acorn barnacles 22 Lepadomorpha (Goose Bamacles) 50 Balanus improvisi/.s Acorn Barnacles 21 Balanomorpha (Acorn Barnacles) 60 Lepas anatifera Goose barnacles 20 Amphipoda 60 Balanus tintinnabulitm Acorn barnacles 18 Isopoda 24 Balanus balanoides Acorn barnacles 16 Decapoda 76 H ydroides norvegica Tubeworms 15 Pycnogonida 8 Balanus amphitrite Acorn barnacles 15 Insecta 2 C onchoderma aitrititm Goose barnacles 15 Conchodernia viigatum Goose barnacles 14 Mollusca...... 212 Amphineura 3 Enteromorplia sp. Green algae 14 Nudibranchiata 32 Cladophora sp. Green algae 14 Pteropoda 4 Schizoporella unicornis Bryozoa 14 Other Gastropoda 59 Tubu;laria larynx Hydroids 14 Pelecypoda 121 Ciona intestinalis Tunicates 13 Tubulai'ia crocea Hydroids 12 Echinodermata...... 19 Crinoidea 3 Ectocarpits sp. Brown algae 11 OphiuroideaAsteroidea 73 HolothuroideaEchinoidea 51 between the assemblages of organisms likely to be Chordata...... 127 found on different types of structure. It is diff- Tunicata 116 cult, however, to state very definitely what these Pisces 11 differences are, or to justify such statements with quantitative data. The amount of information Few species of Pelecypods are recorded although available from examinations of different struc- some such as the oysters and mussels are among tures is very unequal, so that statistical compari- the most important foulers. sons are impossible. The differences also depend Only 50 to 100 species are commonly encoun- not so much on the character of the structures as THE FOULING COMMUNITY 39 on the circumstances under which they are ex- TABLE 5. Numbers of Species of Fouling Organisms posed and the degree of fouling which is permitted on Buoys and Ships to develop before examination. Navigation buoys, Number of Species per Unit which foul heavily before servicing, support a Units Range Average 4 Buoys, Plymouth Sound 31-37 34.0 6 Buoys, Estuary 5-19 14.3 TABLE 4. Frequency of Various Forms in Ship Fouling All 10 Buoys-Milne (6) 5-37 22.4 The numbers indicate the number of ships on which each 83 Ships-Visscher (11) 1-13 4.18 species was reported by Hentschel (3) and Visscher 48 Ships-Hentschel (3) 1-12 4.39 (11). The total number of ships examined was 131. after a month's exposure may give a very inac- ACORN BARNACLES BRYOZOA (conL) curate picture of the fouling organisms available, Balanus improvisus 44 Bitgula tiirbinata 1 since only the rapidly developing forms are re- Balanus eburneus 34 Watersipora citciillata 1 Balanus amphitrite 27 Callopora lineata 1 corded. Balanus tintinnabiilum 25 Callopora sp. 1 Balanus sp. 2S Alcyoiiidimii sp. 1 Some quantitative differences between the char- Balanus crenatus 7 M embranipora savartii 1 acter of the fouling assemblages on ships and Balanus psittacits 3 Electra pilosa 1 Clielonibia patula 2 Scliizoporella unicornis 1 buoys are brought out in Tables 5 and 6. Table 5 Balanus perforatus 1 Scrupocellaria reptans 1 shows the numbers of species recorded from fouled Balanus tulipiformis 1 Chthamalits sp. 1 MOLLUSCS buoys and ships. The average number of species Anomia ephippiwii 31 found on buoys was much greater than on ships. GOOSE BARNACLES M ytilits ediilis 18 Lepas anserifera 5 Ostrea elongata 7 This result reflects the greater complexity of com- Conchoderma aurititni 4 Ostrea sp. 4 position in the mature communities found on Conclioderma virgatmii 3 M ytilus pictus 2 Lepas Iiillii 3 Nudibranchs 2 buoys. Table 6 indicates the percentage of the Lepas anatifera 3 Ostrea parasitica 1 buoys and of the ships examined on which various Poecilasma crassa 2 Anomia fideiias sp. 11 groups of fouling organisms were found. Each HYDROIDS Teredo navalis 1 group occurred more frequently on buoys than on Tubitlaria sp. 30 Campaiiularia sp. 26 ANNELIDS ships, again emphasizing the greater diversity of Laomedea sp. 16 Hydroides Iiexagoiiis 8 species represented in the more maturely devel- Clytia sp. 7 H ydroides norvegica 4 Titbiilaria crocea S Hydroides sp. 1 oped fouling of buoys. The barnacles are the only Campanularia amphora 3 N ereis pelagica 1 group that occurs nearly as frequently on ships Eudendrimii raniosum 3 Nereis sp. 1 as on buoys. The great rapidity with which barna- Laomedea geiiiciilata 2 (unidentified-l1) Laomedea sargassi 1 cle populations may develop, as well as the firm- Campanularia portium 1 TUNICATES Campanularia vorticellata 1 Molgula manhattensis 9 ness of their attachment, may explain their preva- Bougainvillia carolinensis 1 M olgula arenata 4 lence on ships. Free living organisms associated Perigonimus jonsii 1 Botryllus schlosseri 1 Podocoryne sp. 1 Ascidiella virginea 1 with the fouling communities, such as errant Plumiilaridae 1 Diplosoma gelatinosa 1 polychaetes and nudibranchs, are much more gen- (unidentified-5) PROTOZOA erally represented in the buoy fouling. ANEMONES V orticellids 10 In a few instances comparisons have been made Metridium sp. 8 Folliciilina sp. 2 Sagartia sp. 3 ALGAE TABLE 6. Percentages of Ships and Navigation Buoys Fouled by Various Groups. Ship data from Hentschel and Visscher; Buoy CORALS Enteromorpha intestiiialis 39 data from American Waters. The Numbers Represent the Per Astrangia sp. Enteromorpha sp. 19 Ulva lactitca 8 Cent of the Ships or Buoys Examined on which Representatives BRYOZOA Cladophora sp. 5 of Each Group were Found. llf embranipora lacroixii 2S Ulotlirix flacca 4 Ships jl,embranipora sp. 16 Polysiplionia nigresceiis 4 Bowerbankia caudata 6 Ectocarpus confervoides 3 Hentschel V issclier All ships Buoys Alcyonidium mytili 5 Ulva sp. 3 Groitp (48 ships) (83 ships) (131) (373) Alcyonidium gelatinositm 3 Vauclieria sp. 1 Algae 79 33 50 94 M embranipora mono- Stigeoclonium sp. 1 Hydroids 63 49 54 99 stachys 3 Chaetomorpha fibrosa. 1 Anemones 0 12 12 S4 Bugula titrrita 3 Acrochaetium sp. 1 Sedentary Lepralia pertusa 2 Syplioiiales sp. 1 Polychaetes 31 11 18 53 Bugula aviciilaria 1 Oscillatoria sp. 1 Errant Polychaefes 0 2 2 93 Bugula neritina 1 (unidentified-I) Bryozoa 31 45 40 83 N udibranchs 0 2 2 58 Pelecypods 25 22 23 97 more mature community of fouling organisms than Mytilus 15 16 15 77 ships, which are commonly docked before heavy Ostrea 10 8 9 17 Others 6 0 6 84 fouling has accumulated. As a result, greater vari- Barnacles 83 89 87 98 ety is reported from navigation buoys than from o Acorn 83 88 86 94 Goose 19 4 9 24 ships. Test panels which are commonly inspected Tunicates 4 16 12 40 40 . MARINE FOULING AND ITS PREVENTION between the fouling communities and the nat- timate size, and dies after an allotted period. The urally occurring populations of a region. Mac- population may contain organisms of many dif- Ginitie found more species on a lighter at Mon- ferent ages, and wil increase in bulk at a rate terey, California, than could be collected in the which has little apparent relation to the growth immediate environs (5). In the Suez Canal buoys, of its members. Although the individuals may barges, beacons, and wharf piles provided far die, the population as a whole may persist per- richer collections of species than did the bottom manently. In addition, the various members of of the Canal (1). The poverty of the latter may the population influence one another. Crowding be due to the frequent dredging of the soft and may check their growth or modify their form. In sandy bottom and the continual scouring attend- communities composed of several species, more ing the passage of ships. These cases do not invali- complicated relations arise. The presence of one date the view that the bulk of fouling is composed species may favor the growth of another, or a of a small number of species drawn from a much slowly-growing form may crowd out others which larger total of coastwise types. They indicate became established earlier. merely that fouling may not necessarily originate The dominant organism in a community deter- from the immediately adjacent natural popula- mines, to a large degree, its general character and tions. gives the community its name. Thus the natural Although the bulk of fouling is drawn from assemblages dominated by mussels are known as members of the natural population, several forms Mytilus communities. Although no two mussel are known only from records of fouling. Certain beds, or parts of the same bed, are exactly alike acorn barnacles, such as the varieties dorbignyii, in the kinds and proportions of other species costatus, and plicatus of Balanus tintinnabulum, present, mussel beds in general resemble one an- have been found only on ships. Balanus crenatus other more than they differ and may be recognized delicatus is reported only from buoys. A number as a definite entity. Mytilus communities, as ob- of goose barnacles of the' genera Scalpellum and served in fouling, are essentially similar to natural Megalasma have been collected solely on deep-sea mussel beds. They display characteristics which cables. There is no reason to believe that these make them recognizable as something more than forms also have not originated from natural popu- an accidental collection of species. lations as yet undiscovered. Buoys along the coast of the northeastern Fouling is a way of life to which marine organ- United States are usually fouled by the Mytilus isms may turn insofar as they are adapted to live community. Different subordinate species are under the conditions presented by the surface of found associated with the mussels in different an artificial structure. The species adapted to regions. Kelp and the barnacle, Balanus crenatus, adhere to stones and other hard submerged sur- for example, are associated with the mussels north faces most readily take up life on such structures. of Cape Cod, while further south the kelp is less As they develop, the character of the surface prominent and the important barnacle is Balanus changes, and places are provided where many free improvisus. living forms may harbor. Thus the possibilities The character of the communitietì of the sea of occurrence are greatly extended and may include bottom has been shown to be governed by the creatures quite incapable of acting as independent nature of the bottom and its depth (2, 7, 9, 10). foulers. The concept of fouling is consequently The communities of mud, sand, gravel, or rock quite elastic, and the phenomenon is to be under- bottoms are each distinctive. Their distribution stood only by considering, in the most general parallels the distribution of the bottom materials, way, the biological factors which influence the and tends to fall into depth zones more or less growth and development of marine communities. parallel to the shore. In much the same way the. communities of fouling depend upon the character FOULING AS A COMMUNITY 1- of the structures and their conditions of exposure. Although the fouling on a submerged surface Thus mussels rarely attach to ships unless these may be described by naming the species and are moored for long periods, and ships are usually counting their numbers, the assemblages have fouled by a Balanus community, with algae pre- properties of their own which are additional to dominant at the water line. Buoys in bays and those of the separate organisms. Each individual estuaries often support a community dominated grows at a characteristic rate, attains some ul.. by Balanus improvisus or Ciona intestinalis, while THE FOULING COMMUNITY 41 those moored well off shore are fouled with goose REFERENCES barnacles. Buoy anchors often support a com- 1. Fox, M. Zoological Results of the Cambridge Expedition to munity which is different from that on structures Suez Canal, 1924. General Results. Trans. Zoological Soc. London, 22, 1-64, 1926. suspended directly above the bottom. The My- 2. GISLEN, T. Epibioses of the Gullmar Fjord. I, II. Kristine- tilus community is generally confined to the buoy bergs Zoologiska Station 1877-1927; Skriftser., K. Svensk. and chain, and is replaced on the anchor by bar- Vetenskapsakad., No.3, 1-123; No.4, 1-380, 1930. 3. HENTSCHEL, E. Der Bewuchs an Seeschiffen. Int. Rev. ges. nacles. Hydrog. Hydrob. 11, No.3, 4, 238-264, 1923. It may be seen that fouling is not a well de- 4. KIRCHENPAUER, J. U. Die Seetonnen der Elbmundung. Ab- fined entity. The assemblage of organisms to be handl. a.d. Gebiete d. Naturwiss. her. v. d. naturwiss Ver. in Hamburg, 4, No.4, 1-59, 1862. found on an exposed structure depends upon the 5. MACGINITIE, G. E. Littoral Marine Communities. Amer. species naturally present at the site of exposure Midland Nat. 21, No.1, 28-55, 1939. and upon their ability to attach and grow on its 6. MILNE, A. The Ecology of the Tamar Estuary. IV. The Dis- tribution of the Fauna on Buoys. Jour. Marine BioI. Assoc. surface. The characteristics and the activity of the U.K. (n.s.) 24, 69-87, 1940. structure contribute to this selection. In addition 7. PETERSEN, C. G. J. A Preliminary Result of the Investiga- the reproductive habits of the different species tions on the Valuation of the Sea. Rep. Danish BioI. Sta., 23, 29-32, 1915. wil determine which organisms appear first on 8. PRATT, H. S. A Manual of the Common Invertebrate Animals structures exposed at different seasons. The inter- Exclusive of Insects. Revised Edition, P. Blakiston's Son actions of the various kinds which may appear & Co., Inc., Philadelphia, 1935. 9. SHELFORD, V. E. Geographic Extent and Succession in Pacific simultaneously or in succession modify the as- North American Intertidal (Balanus) Communities. Pub. semblage and determine the character of the Puget Sd. BioI. Sta., 7, 217-223, 1930. community which finally emerges. 10. SHELFORD, V. E., A. O. WEESE, L. A. RICE, D. I. RASMUSSEN, and A. MACLEAN. Some Marine Biotic Communities of the These varied factors, which must be taken into Pacific Coast of North America. Part I. General Survey of account in order to understand the communities the Communities. Ecol. Mon., 5, 249-354, 1935. of organisms which are found on artificial struc- 11. VISSCHER, J. P. Nature and Extent of Fouling of Ships' tures, wil be considered in the chapters which Bottoms. BulL. Bur. Fisheries, 43, 193-252, 1927. 12. ZOBELL, C. E. Marine Microbiology. Chronica Botanica Co., follow. Waltham, 1946.