Biodeterioration of fishing craft materials along the Visakhapatnam coast R. Raghu Prakash* & Leela Edwin** *Research Center of Central Institute of Fisheries Technology, Visakhapatnam **Central Institute of Fisheries Technology, Kochi Introduction Marine bio-deterioration today affects the entire economic balance of the Indian fishing industry, which depends upon the efficient service of its fishing industry. Biological fouling or settlement and growth of undesirable organisms on man made structures causes many problems in the marine environment, interfering in a range of maritime activities. The losses due to biodeterioration of materials in enormous. The problem of controlling biofouling and marine borer infestation is extremely complex not only because of the magnitude of organisms and processes involved but also because of the many chemical and physical environmental conditions. The main causes of bio-deterioration in the marine environment is mainly due to due biofouling, marine wood borers, fungal attack and corrosion

Significance of biofouling The settlement and growth of marine organisms on man made underwater structure is one of the process operation in the marine environment causing great monetary losses. Heavy fouling reduces the speed of ships and other vessels by increasing frictional resistance resulting in high fuel consumption, It also interferes with the functioning efficiency of under water acoustic devices and loss of efficiency of underwater propellers. Fishing vessels have to be dry docked periodically which is an added economic loss, in addition to the destruction of surfaces of vessels. The most obvious problem of growth on a steel fishing boats is the eventual corrosion of the hull, leading to the deterioration of the boat . Even before corrosion occurs, if left unattended, organic growth can increase the roughness of the hull, thereby decreasing its maneuverability and increasing drag. This domino effect continues when the boats fuel consumption increases, in some cases by 30%. This in turn has economic and environmental consequences, as increased fuel consumption leads to increased output of greenhouse gases. Economic losses are tremendous, as fuel accounts for up to 50% of marine transportation costs. Biofouling on ships reduces their speed (due to a reduction in hydrodynamics) and maneuverability, causing increased fuel and maintenance costs. On static structures (eg buoys, piers, jetties, offshore oil and gas platforms) biofouling can enhance the corrosion of metal by seawater, reducing the metal’s susceptibility to environmental fracture, and increasing the risk of mechanical failure. Biofouling in air conditioning systems can prevent air-flow, reducing cooling efficiency and increasing energy costs, as well as being foul smelling. Blooms of algae can block both fresh and salt water filtration systems, and require water pipes to be frequently cleaned to prevent blockage.

Fouling is a biological process aided by hydrographical and geographical factors. The establishment of a fouling community can be divided into different phases. Initially a primary film develops comprised of bacteria , fungal spores, diatoms and colloidal organic mates. In the 2nd phase there is the establishment of macrofoulers, which in Indian waters usually consists of hydroids, Barnacles, Tubicolous polychactes, bryozoans mussels, oysters and compound ascidians. As a submerged substratum ages, the fouling complex passes from the establishment to the extinction of different communities, whose compositions are influenced by the abundance of local species and physiochemical conditions of the environment. Characteristics of bio-fouling communities : The bio-fouling communities encountered at Visakhapatnam can be broadly classified into (a) The primary fouling assemblage, which directly attaches to the substratum and (ii) The secondary foulers which live among the primary fouling assemblages. The former is comprised of both solitary and colonial forms. There are about 125 species reported at Visakhapatnam of which 84 species belonged to the primary fouling assemblages and the rest to secondary fouling assemblages. The major fouling communities which represented the communities included hydroids, Serpulids, Ectoprocts, Entoprocls, Sponges, Barnacles, Oyster, Bivalves, Ascidians among the primary fouling group. The secondary fouling community consisted of polychaetes Nematodes, Tubellarians, Amphipods, Copepods, Tanaids, Isopods, Nudibranchs etc. The micro fouless includes diatoms Nitzchia sp , Pleurosiqma sp , Rhizosolania sp, coloninal ciliates zoothamnium. Among the crustacean, barnacles dominated the fouling group of which Balanus amphitrite and Balanus tintinnabulum were dominant. Among bivalves Crassotrea madrasensis Anomia and M. sallei were dominant. The main fouling communities attached with fishes at Visakhapatnam are crustacean bannales and serpulid worm. The climax community is fishing vessels were serpulid worm, namely Serpula vermicularis, hydroides elegans, hydroides lunulifera, Hydroides albiceps, hydroides brachyacanthia, Pomatoceros crosslandi, Pomatostegus polylraema, Pomatocera triqueter, Mercierella enigmaica, Brandiomma nigromaculata. The major groups of foulers encountered at Visakhapatnam is given in table 1. Marine Borers Damage by marine-boring organisms to wood structures in salt or brackish waters is practically a worldwide problem The principal marine borers from the standpoint of wood damage in the Visakhapatnam are described in this section. Shipworms are the most destructive of the marine borers. They are mollusks of various species that superficially are worm-like in form. Teredo furcillatus and Bankia campanellata occur abundantly in Visakhapatnam through out the year . In the early stages of their life, they are minute, free swimming organisms. Upon finding suitable lodgment on wood, they quickly develop into a new form and bury themselves in the wood. A pair of boring shells on the head grows rapidly in size as the boring progresses, while the tail part or siphon remains at the original entrance. Thus, the animal grows in length and diameter within the wood but remains a prisoner in its burrow, which it lines with a shelllike deposit. It lives on the wood borings and the organic matter extracted from the sea water that is continuously being pumped through its system. The

entrance holes never grow large, and the interior of wood may be completely honeycombed and ruined while the surface shows only slight perforations. Martesia striata also occur abundly in Visakhapatnam . Like the shipworms, the Martesia enter the wood when they are very small, leaving a small entrance hole, and grow larger as they burrow into the wood. They generally do not exceed 64 mm (2-1/2 in.) long and 25 mm (1 in.) in diameter but are capable of doing considerable damage. Another distinct group of marine borers are crustaceans, The principal borers in this group are species of Limnoria and Sphaeroma Their attack differs from that of the shipworms and the Martesia in that the bore hole is quite shallow; the result is that the wood gradually is thinned from the surface inward through erosion by the combined action of the borers and water erosion. Also, the Limnoria and Sphaeroma do not become imprisoned in the wood but may move freely from place to place. Limnoria are small, 3 to 4 mm (1/8 to 1/6 in.) long, and bore small burrows in the surface of wood. Although they can change their location, they usually continue to bore in one place. When great numbers of Limnoria are present, their burrows are separated by very thin walls of wood that are easily eroded by the motion of the water or damaged by objects floating upon it. Protection of fishing craft One of the primary ways to prevent biofouling is to select the appropriate material out of which to make a structure. This may be accomplished in coordination with the biological knowledge of biofouling organisms. For example, zebra mussels find aluminum-bronze distasteful, so they tend to avoid such structures. Cupronickels (copper-nickel alloys) have good biofouling and corrosion resistance, and therefore are often used for surfaces or surface coatings. Two of the most popular materials used are 90/10 and 70/30 copper-nickel alloys (90%Cu10%Ni and 70%Cu-30%Ni, respectively). This method may not be effective in every situation, especially with ships that travel great distances through waters of different temperatures and salinity, rendering a change in materials' resistances to biofouling. One of the earliest methods of solving the problem was simply to scrape the hulls of ships. This solution, although simple and relatively effective, poses one not so obvious major problem spread of invasive species. This is illustrated best with the population explosion of Mytilopsis sallei in the harbour water of Visakhapatnam . The mussels are picked up by fishing equipment, ships and other vessels and transported to non-native waters where they wreak havoc on native environments. When cleaning (or scraping) becomes time consuming or ineffective, industries turn to perhaps the most widely accepted method of controlling and preventing biofouling - antifouling coatings. One of the most popular of these is tin-based coatings, specifically triorganotin- or organostannic- or simply, TBT-coatings. These are also considered self-polishing, as there is a controlled hydrolysis (decomposition) of the surface, which releases the TBT in a slow, steady fashion from the substrate. When a substrate (e.g. a ship's hull) is in motion, the water wears the

compound away, leaving behind particles. TBT-coatings are highly effective in reducing/controlling biofouling; however, they are also highly toxic to marine organisms. TBTcoatings are toxic to biofouling organisms, but also to non-target organisms. TBT interferes with major biological processes such as growth, reproduction and immunity, on a cellular level. Some antifouling paints have a leaching rate of more than 4 micrograms of TBT per day. That may sound insignificant, but damage to an organism can occur in low concentrations - as little as less than 1 ppb (1 part per billion) - and the life of a TBT-coating can be as great as five years. Traditional fishing crafts of Visakhapatnam are mainly made of wood. Two major factors responsible for biodeterioration are decay by fungi and insect damage. Wood is also attacked by marine boring and fouling. Traditional fishermen of /Andhra Pradesh use various indigenous materials for preservation of their craft. They include sardine oil, shark liver oil, cashew not shell liquid and various vegetable oils. These are normally effective for a short duration and requires to be applied periodically. These indigenous preservatives have no long effect on the organisms responsible for bio-deterioration of wood. Their action is limited to provide a water repellent surface. Recommended wood preservatives : Chemical wood preservatives have been developed, which are effective than traditional presser valve. These chemical wood preservatives contains ingredients that protect the wood against action of organism that are responsible for deterioration of timbers. Three types of wood preservatives namely, water borne, oil borne and solvant type are now available. Water borne wood preservatives like Copper Chrome Arsenic (CCA) commonly known as ASCU are effective against fungi and insects. Among oil borne preservatives Creosote, which is a fraction of distillate from coal tar is effective against decay due to fungi, insect attack and reduce the risk of splitting and surface cracking of wood. Creosote is recommended for preservation of timbers in marine applications. Solvant type preservatives like Pentachlorophenols, Naphthanates of zinc, Copper and Tributyl tin oxide do not affect the strength of wood and do not leach out from the timbers. Due to concerns about polluting waters and poisoning organisms, many have pursued research to create non-toxic coatings. One of these is known as a foul-release coating. Usually made of polymers (plastics), these coatings are non-toxic and are thought to have a natural resistance to biofouling by creating a low surface tension. Polymers utilized in these coatings are silicones and fluoropolymers and ethyl vinyl acetates. Another technique commonly used against diatoms is called pulse laser irradiation - the longer the duration of each pulse, the greater the mortality of organisms. Unfortunately, this radiation is not species-specific and can harm non-target organisms. Plasma pulse technology does not use chemicals or heat; it transmits energy directly into the water, which may cause harmful shockwaves or steam bubbles. Pulsed electric fields, frequently used in pipes, create acoustic waves. Unlike plasma pulse technology, this process does not create shockwaves that could affect cooling/heating systems. In addition, electric fields do not kill, but stun organisms, clearly lowering mortality of non-target organisms. Another unique method for decreasing biofouling starts not with coatings, not with materials selection, but with where the materials (in this case, boats) are housed when not in use. Enclosed marinas are much more likely to contain biofouling organisms than unenclosed marinas. Tides and currents assist in the flushing and renewal of water in a marina. Harbors can

be designed to ensure maximum flushing capacity, because marinas with breakwaters retain more water than marinas without, leaving a greater build-up of fouling species. Sheathing for Protection Experiments have shown the lasting protective value of a metallic sheathing on the wooded hull below the water line with Aluminium magnesium alloy sheathing particular have been very much relied on as a material against marine borers and foulers The alloy is light, Resistant to sea water and Cheap. Fiber glass sheathing is also effective as a protection against marine wood boring organisms.

References Nagabhushanam R “ Seasonal settlement of molluscan ad wood borers in Visakhapatnam” Bull. Of Nat. Inst. Sci. of India No 19, 1962

Ebeling, W. 1975. Wood destroying insects and fungi. In: Urban entomology. Berkeley, CA: University of California, Division of Agriculture Science: 128–216. Ganapathi P N and Nagabhushanam R (1955) Notes on the biology of some wood borering organisms of Visakhapatnam harbour. Timber dryers and preserves Association India 1, 19 Highley, T.L.; Scheffer, T.C. 1978. Controlling decay in above-water parts of waterfront structures. Forest Products Journal. 28: 40–43. Hunt, G.M.; Garratt, G.A. 1967. Wood preservation, 3d ed. The American forestry series. New York: McGraw–Hill Book Company . Jones, E.B.G.; Eltringham, S.K., eds. 1971. Marine borers, fungi and fouling organisms of wood. In: Proceedings of Organization for Economic Cooperation and Development; 1968 March 27–April 3; Paris, France. OECD. Nagabhushanam R “ Seasonal settlement of molluscan ad wood borers in Visakhapatnam” Bull. Of Nat. Inst. Sci. of India No 19, 1962 NAgabhushanam R and R. Sarojini “ An over viw of Indian research on marine wood boring and fouling organisms. In fouling organisms of the iNdian ocean – biology and control Technology Ed. R. NAgabhushanam & mary francis Thompson Oxford & IBH Publications

Table 1 : Major Groups of Foulers of Visakhapatnam PORIFERA Halichondria panicea Sigmadocia punila Tethya aurantium COELENTERATA Pennariidae Pennaria disticha Laomedia bistriata Clytia noliformis Sertulariidae Sertularia sp. Diphasia sp. Haleciidae Halecium sp. Sagartiidae Sagartia sp. PLATYHELMINTHES Turbellaria Pseudoceridae Pseudoceros indicus Stylocopoma sp. Planocera sp. ANNELIDA Phyllodoce sp. Syllis variegata Syllis gracilis Perinereis cultrifera Pseudoneries anomala P. gallapagensiskinberg P dumerilli Nereis glandincta Diopatra neapolitana Polydora ciliata Capitella capitata Heteromastus sp. Notomastus sp. Dasychone cingulata Loimia medusa Sabellestarte sp. Pseudoeurythoe microcephala Cirratulus cirratus Serpula vermicularis Hydroides norvegica Pomatoleios crosslandi Pomatoceros trigueter

Vermilopsis pygidialis Mercierella enigmatica Neodexiospira pseudocorrugata Paradexiospira vitrea ARTHROPODA Pycnogonum indicum Laopjonte cornuta L. hirsuta Balanus tintinnabulum B. amphitrite Ampelisca zamboangae Ampithoe sp. Corophium triaenonyx C. acherusicum Erichthonius brasiliensis Hyale honolulensis Elasmopus pectinicrus E. rapax Podoceros brasiliensis Apseudes sp. Sphaeroma walkeri Dynamella sp. Exosphaeroma sp. Synidotea variegata Cirolana fluviatilis Oniscus sp. Ligia sp. ECTOPROCTA Membranipora tuberculata M. tenuis Conopeum commensala Electra bengalensis E. tenella E. pilosa E. bellula Alderina arabianensis Farciminariidae Nellia tenella Bicellariellidae Bugula neritina B. stolonifera B. bengalensis Scrupocellaria harmeri

S. diegensis S. talonis ASCOPHORA Hippopodina feegeenensis Hippopodina lafontii Hippoporina Americana CTENOSTOMATA Nollella papaunensis Victorella pavida Sundanella sibogae Bowerbankia gracilis Zoobotryon verticellatum Amathia distans Buskia nitens CYCLOSTOMATA Crisia elongata Milne Edwards ENTOPROCTA Pedicellina cernua Barentsia gracilis Loxosomatoides laevis MOLLUSCA Pelecypoda Modiolus striatulus M. metcalfei Septifer bilocularis Musculus strigatus Perna viridis Isognomon legumen Ostreidae Crassostea forskalii C. madrasensis Anomidae Anomia achaeus Mytilopsis sallei Avicula sp. Arca sp. Gastropoda Cellana radiata Littorina undulata L. subgranosa Nerita albicella

N. plicata Thais tissoti Turbo sp. Nudibranchia Discodoris concinna Doriopsilla miniata Caloria militaris CHORDATA Botryllus schlosseri B. leachi Symplegma viride Herdmania ennurenis Molgula sp. Ascidella sp. CRUSTACEA Alpheus strenuous Pachygrapsus minutus Grapsus grapsus Charybdis Orientalis Poreella sp.