Weak Effects of Epibiota on the Abundances of Fishes Associated with Pier Pilings in Sydney Harbour

Biogenic habitats have profound effects on the distribution and abundances of many organisms. Epibiota are major biogenic components of hard substrata in marine habitats, particularly on artificial structures such as pier pilings, and have the potential to influence organisms associated with these structures. This study tested hypotheses about effects of epibiota on abundances of fishes associated with pilings in Middle Harbour, Sydney. Amount of epibiota had no effect on abundances of most species of fish, suggesting that epibiota are not important resources for these species. Abundances of the hulafish, Trachinops taeniatus, were, however, found to be greater around pilings with large than pilings with small amounts of epibiota at one site, at each of two times. Experimental removals of epibiota from pilings were done to test the hypothesis that epibiota are an important resource to T. taeniatus. Despite great temporal fluctuations in abundances over the duration of the experiment, the response of T. taeniatus to the removal of epibiota from pilings was as predicted, falling to zero following removal of epibiota. Although this suggests that epibiota are an important resource for this species, this pattern was spatially and temporally variable. We suggest that variation in the amount of epibiota has minor effects on the abundances of fishes around pilings.     

Food habits of small fishes in a common reed <Emphasis Type="Italic">Phragmites australis</Emphasis> belt in Lake Shinji,Shimane, Japan

To clarify the feeding habits of reed fishes, the gut contents of 13 fish species collected in a Phragmites australis belt in Lake Shinji were examined. Six species showed ontogenetic and/or seasonal changes in food use patterns. Smaller individuals generally preyed on small planktonic items (e.g., calanoid and cyclopoid copepods) or small crustaceans (gammaridean amphipods), subsequently changing to other prey items (e.g., mysids and filamentous algae) with growth. The most important dietary items for the reed fish assemblage comprised planktonic copepods, gammaridean amphipods and mysids. However, the relative importance of these changed seasonally, gammaridean amphipods being the most important in autumn and winter, and planktonic copepods and mysids the most important in spring and in summer. Cluster analysis based on dietary overlaps showed that the reed fish assemblage comprised five feeding guilds (planktonic-copepod, mysid, gammaridean-amphipod, filamentous-algae, and detritus feeders). Of these, the three former guilds were the most abundantly represented, whereas detritivores were represented by a single species.     

Abundance and colonization potential of artificial hard substrate-associated meiofauna

Meiofauna are known to live on hard substrates in association with periphytic and epiphytic algae and attached epibiota; however, the abundance, diversity and colonizing abilities of hard-substrate meiofauna have been poorly documented. We quantified meiofauna living on microalgal-covered pilings associated with a wood pier in a shallow (<2 m deep) estuarine embayment with the use of a suction sampler, and compared colonization of pier-piling and sediment-dwelling meiofauna onto collectors that capture suspended meiofauna from the water column. Collectors were small mesh pads (159 cm³) suspended at mid-water depth, and their size and structural complexity were similar to floating or drifting masses of macroalgae that may be colonized by meiofauna. Sediment was collected by coring, and copepod (to species) and nematode (to genera) colonists on mesh pads were compared with pier-piling and sediment communities. Abundance of total meiofauna averaged 124±13.6 (S.E.) on pier pilings, compared to 2092±274.6 individuals 10 cm⁻² in surrounding sediment. Phytal copepods (free-living copepods with prehensile first legs and dorsoventrally and laterally compressed body forms) and copepod nauplii dominated pier-piling collections, but nematodes were dominant on faunal collectors and in sediment. Phytal copepods also were abundant on faunal collectors but were rare in sediments. Copepod and nematode diversities were similar, but species composition was largely nonoverlapping, in pier pilings and sediments. Net recruitment of meiofauna to faunal collectors averaged about 900 individuals collector⁻¹ day⁻¹ during the 1-week experiment. Nematode and copepod colonists on faunal collectors were both much more similar to pier-piling than to sediment assemblages. These data suggest that meiofauna are abundant and diverse on algal-covered pier pilings, and they may become more important to marine ecology as artificial hard substrates increase with increasing urbanization. Furthermore, pier-piling meiofauna appear to readily migrate into the water column and probably contribute to a rapidly dispersing pool of meiofauna in estuaries.     

Detritus and Epibiota on Artificial Substrata: The Possible Role of Food in Structuring Hawaiian Epiphytal Amphipod Communities

Epiphytal amphipods prefer artificial substrata (bottle brushes) which accumulated epibiotic coatings while submerged in the sea for a period of up to 15 days. There is evidence that these amphipods eat epibiota on algae (predominately Padina japonica YAMADEA 1931 and Dictyota crenulata AGARDH 1847) and that food availability may be a factor which helps structure epiphytal amphipod communities.     

The characteristics of feeding of Diaphus theta (Myctophidae) in the northwestern part of the Pacific Ocean in the Summer-Autumn period

The feeding of Diaphus theta in the zone of the subarctic front and in Pacific waters off the Kuril Islands in November 2001 and in July–August 2002 was studied. Interzonal plankton [euphausiids (mainly Euphausia pacifica), copepods (Metridia pacifica), and amphipods (Themisto pacifica)] dominated in the food bolus. As fish grow, the proportion of copepods decreases, the proportion of euphausiids and amphipods increases in stomachs, and the food spectrum extends. One considerable peak in the feeding (in both the summer and autumn periods) occurring in the nighttime was revealed. The most intensive feeding takes place in the dark time of the day in the epipelagial due to euphausiids and amphipods; in the light time of the day, the feeding activity declines. Fish feed mainly on copepods in the upper pelagial. The daily ration of D. theta was 1.5% of the weight of fish in the summer period and 3.2% in the autumn period.     

Diet,food preference,and algal availability for fishes and crabs on intertidal reef communities in southern California

Synopsis Herbivory by wide-ranging fishes is common over tropical reefs, but rare in temperate latitudes where the effects of herbivorous fishes are thought to be minimal. Along the west coast of North America, herbivory by fishes on nearshore reefs is largely restricted to a few members of the Kyphosidae, distributed south of Pt. Conception. This paper presents information on natural diets and results from feeding choice experiments for two abundant kyphosids from intertidal habitats in San Diego, California —Girella nigricans andHermosilla azurea, and similar data for the lined shore crab,Pachygrapsus crassipes, which also forages over intertidal reefs. These results are compared with the availability of algae in intertidal habitats measured during summer and winter, on both disturbed and undisturbed habitats. The diets of juveniles ofG. nigricans andH. azurea collected from nearshore habitats were dominated by animal prey (mainly amphipods), but adults of these fishes, andP. crassipes, consumed algae nearly exclusively, with 26, 10, and 14 taxa of algae identified fromG. nigricans, H. azurea, andP. crassipes, respectively. Algae with sheet-like morphologies (e.g.Ulva sp.,Enteromorpha sp., members of the Delesseriaceae) were the principal algae in the diets of the fishes, and calcareous algae (e.g.Corallina sp.,Lithothrix aspergillum) and sheet-like algae (Enteromorpha sp.) comprised the greatest identifiable portion of the shore crab's diet. Feeding choice experiments indicated that the fishes preferred filamentous algae (e.g.Centroceras clavulatum, Polysiphonia sp.,Chondria californica) and sheet-like algae (e.g.Enteromorpha sp.,Ulva sp.,Cryptopleura crispa) over other algal morphologies, whereas the shore crab chose jointed calcareous algae (e.g.Lithothrix aspergillum, Corallina vancouveriensis, Jania sp.) most frequently. The diets and preferences for algae by the fishes were generally most similar to the assemblage of algae available in early successional (disturbed) habitats during summer when sheet-like and filamentous algae are abundant. The shore crab exhibited the opposite trend with a diet more similar to late successional (undisturbed) habitats.     

Amphipods exclude filamentous algae from the Western Antarctic Peninsula benthos: experimental evidence

Hard bottom, subtidal communities along the Western Antarctic Peninsula are dominated by forests of large, chemically defended macroalgae that support a very dense assemblage of amphipods. Free-living filamentous algae are rare in the subtidal, but filamentous algal endophytes are common in many of the larger macroalgae, both likely as the result of amphipod grazing pressure. Filamentous algae are common in the intertidal, but primarily in the upper intertidal and on high-energy shores where amphipods are likely to be excluded much of the time. We tested the hypothesis that free-living, filamentous algae would be rapidly consumed if transplanted from the intertidal to the subtidal, and our results clearly supported this hypothesis. The filamentous, intertidal green alga Cladophora repens was transplanted to the benthos in 6 different macroalgal habitats. Control algae were transplanted in 3 m deeper waters nearby (usually 12 m or less laterally) but suspended 3 m off the bottom where amphipods are absent or rare. Overall consumption during approximately 6 h on the bottom ranged from 22 to 98% of the initial biomass, while significantly less biomass loss occurred in the water column.     

Community structure and diet of roving herbivorous reef fishes in the Abrolhos Archipelago, south-western Atlantic

Community structure and diet of roving herbivorous reef fishes were analysed in 13 study sites around the five islands of the Abrolhos Archipelago, north-eastern Brazil (17°58' S; 38°42' W). This area has been part of the Abrolhos Marine National Park since 1983. Abundances and diets of fishes within the families Scaridae, Acanthuridae and Kyphosidae were compared among groups of sites differing in benthic community structure and exposure regime. The abundance of roving herbivorous fishes was higher in shallower sites than in deeper sites. At all study sites, observations of total herbivorous reef fish community structure revealed that 64% of fishes were acanthurids, 33% were scarids and only 4% were kyphosids. This pattern was predominant in all study sites. The majority of fishes examined in this study had the bulk of their diet based on both algae (35–90%) and detritus (35–65%). Among groups of algae, filamentous algae were the most commonly consumed as the majority of roving herbivorous fishes in Abrolhos feed as scrapers and excavators. The exceptions were the kyphosids, which had a diet consisting primarily of macroalgae (mainly Phaeophyta), and Acanthurus coeruleus that consumed mainly turf algae and very little detritus. The data collected indicate that roving herbivorous fishes in the Abrolhos Archipelago are more abundant at calm sites where detritus and delicate algae, their major food resources, are more abundant. The results presented here, along with underwater observations, suggest that the abundance and diet of these three fish families are associated with substratum cover.     

Feeding habits of ocellate spot skate,Okamejei kenojei (Müller & Henle, 1841), in coastal waters of Taean,Korea

The feeding habits of Okamejei kenojei were studied using 592 specimens collected in the coastal waters of Taean, Korea from April 2008 to March 2009. O. kenojei is a bottom‐feeding carnivore that consumes mainly shrimp, fishes, and crabs. Its diet also includes small quantities of amphipods, mysids, cephalopods, euphausiids, copepods, isopods, and polychaetes. The total length (TL) of individuals in this study ranged from 8.2 to 49.0 cm. Cluster analysis based on %IRI (index of relative importance) identified three size classes. Group A (< 20 cm TL) ate primarily caridean shrimp and amphipods; group B (20–30 cm TL) ate exclusively shrimp; and group C (> 30 cm TL) ate penaeoidean shrimp, fishes, and crabs. O. kenojei showed ontogenetic changes in feeding habits. Although shrimps were the primary food consumed by all size groups, the proportion of shrimp in the total diet decreased and the consumption of fishes and crabs gradually increased with the body size of O. kenojei. Size of the prey organisms also increased. Smaller individuals fed mainly on small prey, such as amphipods, mysids, and small shrimp, whereas larger individuals preferred larger prey, such as larger shrimp, fishes, and crabs. The size‐related diet breadth and the percentage of empty stomachs were significant; the diet breadth gradually increased with body size, whereas the percentage of empty stomachs decreased. Seasonal changes in the O. kenojei diet were not significant, but shrimp constituted 97.3% of the summer diet by %IRI. Seasonal changes in diet breadth and the percentage of empty stomachs were not significant.     

Diet and feeding niches of juvenile Gadus morhua, Melanogrammus aeglefinus and Merlangius merlangus during the settlement transition in the northern North Sea

A study on the feeding ecology of juvenile cod Gadus morhua, haddock Melanogrammus aeglefinus and whiting Merlangius merlangus during the pelagic to demersal transition was carried out on fishes sampled throughout their settlement season at a local nursery ground in the north-western North Sea, off the Scottish east coast. A comprehensive quantitative taxonomic analysis of the diets, as described in the paper, showed the emergence of distinctive feeding niches, minimizing the potential for competition between species and size categories. The diet of the juveniles changed with fish size, water depth, time of year and distance offshore. Small G. morhua were present in the study area earlier in the season, settled further inshore and ate a higher proportion of pelagic prey (copepods) and as size increased they moved into deeper waters and targeted larger, more benthic prey. As M. aeglefinus grew larger and moved into deeper waters, a diet of largely copepods, amphipods, pelagic Ammodytes spp., cyprids and pelagic gastropods evolved to one dominated predominantly by fishes and benthic invertebrates. In the case of M. merlangus, widespread ages and sizes throughout the sampling season, a consequence of their more protracted spawning season, resulted in dietary changes which were more likely to be influenced by seasonal changes in the prey field, in addition to developmental (size) changes, than the diets of the other two species.     

Small-scale recruitment variation in a temperate fish: the roles of macrophytes and food supply

Synopsis The availability of reef-related resources, particularly food and shelter can play a significant role in determining the distribution and abundance of reef fishes. Much of the structure on temperate reefs is provided by macroalgae, and variability in the density of temperate reef fishes at large spatial scales (100's of meters) can often be explained by variation in macroalgal cover or density. In this study I investigated the role of macrophytes and associated food resources on the recruitment of a temperate fish, Tautogolabrus adspersus, at a small spatial scale (0.25 m²). No relationship between the density of new recruits and the percent cover of kelp, foliose or filamentous algae was observed. Multiple regressions revealed that less than 8% of variability in recruitment could be explained by variability in macroalgal cover. However, recruits were found in higher abundance in patches containing many functional forms of seaweeds than in patches dominated by a single form. A wide variety of prey were available for use by cunner recruits; however, crustaceans and mussels were the only common components of their diet, and crustaceans were clearly the most preferred prey. The prey composition in patches where fish were present was compared to randomly selected patches. Significantly greater numbers of isopods, amphipods and newly settled mussels were present in patches where fish were present than in randomly selected patches. The data presented in this study contradict previous work that has shown algal structure to be important in determining patterns of abundance and food supply to be of little significance. A conceptual model is proposed suggesting that settling fish select habitats in a hierarchical manner largely based on their dispersal tendencies. Hierarchical selection of habitats results in different attributes of the habitat being selected during different life-history intervals.     

Feeding ecology of two lanternfishes Diaphus garmani and Diaphus chrysorhynchus

The feeding ecology of two dominant lanternfishes Diaphus garmani and Diaphus chrysorhynchus was studied in the continental slope region of the East China Sea, off western Kyushu (31–33° N; 128–130° E). Stomach contents of D. garmani were composed mainly of crustacean zooplankton, such as copepods, euphausiids, decapod larvae and amphipods, and also of appendicularians. Stomach contents of D. chrysorhynchus were composed mainly of crustacean zooplankton, cephalopods and fishes. Diel changes in stomach fullness indicated that D. garmani fed more actively at night than in the day. On the other hand, although feeding activity of D. chrysorhynchus did not change drastically between day and night, it tended to feed on large prey items in the benthopelagic zone during the day and on zooplankton in the epipelagic zone at night. Daily rations of food were estimated to be 2·54% of body dry mass for D. garmani, and 2·38% of body dry mass for D. chrysorhynchus.     

Seawater-atmosphere O(2) exchange rates in open-top laboratory microcosms: application for continuous estimates of planktonic primary production and respiration

Foraging by predatory fish is thought to be one of the primary ecological processes affecting the abundances of plants and animals in subtidal habitats. The importance of this process was assessed on the subtidal surfaces of urban structures (pontoons and pilings) that represent major coastal habitats for marine organisms. Fish feed with greater intensity on epibiota attached to pilings than pontoons and it was hypothesised that greater predation on pilings explained why the structure of epibiotic assemblages differs between these habitats. I predicted that the structure of epibiotic assemblages would develop differently between pilings and pontoons in the presence of fish (plates open to predation) but not in the absence of fish (plates inside exclusion cages). Results revealed large differences in abundance between pilings and pontoons that were largely independent of the caged and uncaged plates. Predation may be intense (as it appeared on pilings) but unimportant because it does not explain observed abundances of prey (epibiota between pilings and pontoons).     

Diel variation in feeding rate and prey composition of herring and mackerel in the southern Gulf of St Lawrence

Diel feeding patterns of herring Clupea harengus and mackerel Scomber scombrus in the southern Gulf of St Lawrence were examined based on samples obtained by midwater trawling between 19 and 26 June 2001. Within 3 h time periods, stomach contents tended to be more similar between fish from the same tow than between fish from different tows. Thus, in contrast to previous diet studies, which have used individual fish stomachs as independent observations, tow was used as the experimental unit in statistical analyses in this study. Diel patterns in stomach fullness were identified using generalized additive models. Two peaks in stomach fullness occurred for herring, one in the morning and the other in the evening. Mackerel showed an increase in feeding intensity throughout the day with a peak in mid‐afternoon. The diel changes in stomach contents suggested rapid gastric evacuation rates for both species, especially for herring. The estimate of the instantaneous evacuation rate for herring was twice that for mackerel. Calanus copepods (mainly C. hyperboreus ), fishes (mainly capelin Mallotus villosus ) and euphausiids were the main prey found in the stomachs of both species. Calanus copepods dominated the diet of herring regardless of time period. They also dominated the diet of mackerel during the late afternoon, evening and night while fishes and euphausiids were dominant during the morning and early afternoon. These diel patterns emphasize the need for sampling throughout the day and night in order to estimate ration and diet composition for bioenergetic and ecosystem models.     

Observations on the life history of the belted sandfish,Serranus subligarius (Serranidae)

Synopsis The biology of Serranus subligarius, a typical inhabitant of low limestone reef outcroppings and artificial reefs from North Carolina to Florida and in the northern Gulf of Mexico, was studied on inshore jetties in the northeastern Gulf of Mexico from February 1974 to April 1975. The length-weight relationship was expressed by the equation W = 0.000006L^3.431. Growth was greatest in the first year (43.5 mm SL) and declined in the remaining three years of life (17.3, 10.5, and 7.1, respectively). In individuals larger than 40 mm SL, gammaridean and caprellid amphipods were the most numerous food items but crabs, shrimp, and fishes were the most important food items by weight. In individuals less than 40 mm SL, copepods were the most numerous food item, but gammaridean amphipods and shrimp were the most important items by weight. Two incidents of cannibalism were recorded. The ovotestis of the belted sandfish is composed of two lobes which are broadly united posteriorly, with the testicular tissue restricted to a broad band encircling the posterior region of the gonad. Age-group 1 fish are functional synchronous hermaphrodites. Testicular tissue matures in the fall or winter of a fish's first year (all specimens examined histologically, including those from the nonspawning season, contained flagellated spermatozoa) while ovarian tissue matures in the following spring. Spawning season in 1974 extended from late April or early May to September. Crossfertilization is the usual reproductive mode, although individuals are capable of selffertilization.     

Partitioning of food resources among Sillago japonica, Ditremma temmincki, Tridentiger trigonocephalus, Hippocampus japonicus and Petroscirtes breviceps in an eelgrass, Zostera marina, bed

We carried out dietary analysis on five numerically abundant fishes, Sillago japonica, Ditremma temmincki, Tridentiger trigonocephalus, Hippocampus japonicus and Petroscirtes breviceps in an eelgrass bed in Kwangyang Bay, Korea. Comparisons between species demonstrated that the dietary composition of each fish species was significantly different from that of every other species. Although gammarid amphipods and caprellid amphipods were consumed by all species, their individual contributions to each species' diet varied. Furthermore, polychaetes contributed to the diets of S. japonica and T. trigonocephalusand crab larvae were consumed byD. temmincki. Algae and eelgrass were not consumed by four fish species and made only a minimal contribution to the diet of P. breviceps. The diet of each fish species except H. japonicus underwent size-related changes; smaller fishes consumed gammarid amphipods, mysids and copepods, while larger fishes ate polychaetes, gastropods, isopods and other fishes. Differences in the prey organisms consumed of each individual species could be often related to differences in mouth length and width. S. japonica, D. temmincki, T. trigonocephalus, and P. breviceps underwent also a significant diel changes that could be related to differences in foraging behavior and/or prey availability. Thus, use of vision to detect prey would account for the greater daytime consumption of copepods by S. japonica and of crab larvae by D. temmincki, whereas the nocturnal emergence of gammarid amphipods, polychaetes and isopods from the substrate explained their greater consumption by S. japonica, D. temmincki, T. trigonocephalusand P. breviceps at night. Dietary breadth was greater for species with larger mouth dimensions.     

The food and feeding habits of the silver pomfret, Pampus argenteus (Euphrasen), in Kuwait waters

The food habits of the silver pomfret, Pampus argenteus (Euphrasen 1788), in Kuwait waters were investigated by examining the stomach contents of 738 specimens collected from May 1996 to April 1997. Their diet consisted of a broad spectrum of food types, but Crustacea were dominant, with copepods and their eggs constituting 39 % other non-copepod Crustacea constituted 16 %. The next major food group was Bacillariophyta (21 %), followed by Mollusca (11 %), fish scales (10 %) and, finally, fish eggs and larvae (3 %). In summer the species fed on a wider variety of food items than in winter. Copepods, other non-copepod crustaceans, and molluscs tended to occur in the stomachs in higher frequencies with an increase in P. argenteus size (up to 18.5–20.4 cm), while the bacillariophytes tended to increase in stomachs at fish sizes between 22.5–24.5 cm. Analysis of monthly variations in stomach fullness indicated that feeding intensity fluctuated throughout the year, with a low during August and September, corresponding to the spawning period.     

Diet of five species of the family Myctophidae caught off the Mariana Islands

Myctophids are important components of marine food webs, but little is known about the diets of many species in large stretches of the ocean. To fill this knowledge gap, Myctophum lychnobium, Symbolophorus evermanni, Centrobranchus andreae, Myctophum aurolaternatum, and Myctophum nitidulum were collected off the previously unsampled Mariana Islands in 2007. Myctophum lychnobium predominately consumed pelagic molluscs (28 % by number), amphipods (26 %), and copepods (24 %). Symbolophorus evermanni consumed copepods (53 %) and larval fishes (22 %). Centrobranchus andreae consumed molluscs (90 %). Little dietary overlap occurred among these fishes, and the reliance on molluscs was unusual compared to results from previous studies.     

Trophic relationships among concentrated populations of small fishes in seagrass meadows

Changes in available food and utilized foods for a densely populated guild of animals can uncover periods of niche displacement among particular consumer species or their separate size classes. Dense populations of small fishes and their foods were çensussed for 13 months and studied experimentally in shoalgrass and turtlegrass meadows of Redfish Bay, Texas. Feeding habits were determined with respect to prey availability, and illustrated the extent to which seasonal partitioning of food corresponded to food depletion among these abundant consumers in seagrass meadow food webs. The darter goby, code goby, pinfish, and Gulf pipefish were the most common species throughout the year. Although the darter goby did not show distinct ontogenetic changes in food habits, the code goby, Gulf pipefish, and pinfish demonstrated major ontogenetic progressions of foods selected.Food availability in the seagrass meadows changed seasonally. When major prey such as amphipods were abundant, during spring, many fish species showed high overlap in food use. Regardless of food availability, the code goby and Gulf pipefish fed mainly on amphipods or copepods. The more common darter goby and pinfish seasonally changed their diets with changes in food availability; the darter goby and pinfish were more carnivorous during spring, but they largely consumed epiphytic algae during summer. Cage experiments were used to monitor foods confined with elevated densities of pinfish and darter gobies, relative to control cages at natural overall densities. Prey items in the former cages decreased sharply, with corresponding dietary shifts by these common fishes. During resource depletion, these changes in resource use by these naturally concentrated consumers appeared as temporary partitioning of available resources. This shift occurred during both natural (seasonal) and experimental depletions of food, and appears to result from increased interspecific and intraspecific competition during periods of depleted preferred foods.     

Floating pontoons create novel habitats for subtidal epibiota

Urban structures in the form of pontoons and pilings represent major coastal habitats for marine organisms and understanding the factors causing abundances of organisms to differ between these and natural habitat has been neglected in the study of coastal ecology. It has been proposed that composition of substrata explain differences previously described between subtidal assemblages of epibiota on rocky reef (sandstone) and pontoons (concrete) in Sydney Harbour, Australia. This study tested the hypothesis that differences in the composition of substratum (sandstone vs. concrete) independent of type of habitat (rocky reef vs. pontoon) affects the development of epibiotic assemblages. This was tested by experimentally providing substratum of the two types in both habitats. Epibiotic assemblages were unaffected by the composition of substratum but strongly affected by the type of habitat; demonstrating that pontoons constitute novel habitats for epibiota. This result highlights a need for determining how current ecological understanding of subtidal epibiota, which is heavily based on studies of urban structures (pilings and pontoons), relates to natural reef. Future tests of hypotheses about the nature of these differences will not only contribute to better ecological understanding of epibiota and their use of urban structures as habitats, but also to better predictions of future changes to the ecology of coastal habitats.