A new quantitative air-lift sampler for collecting macroinvertebrates on stony bottoms in deep rivers

SUMMARY. 1. As three previous comparative studies of deep-water samplers for benthic macroinvertebrates in rivers highlighted the need for a quantitative sampler for use on stony substrata, a new air-lift sampler was developed. It can be operated from a small boat by two people, weighs 13.5–20.0 kg, depending on the length of riser used, and extends the maximum range of substrata that may be sampled quantitatively from 16–32 mm to 128—256 mm. The sampling area is isolated by forcing a collecting cylinder into the substratum, and rapid evacuation of the contents is assisted by a vibrator.
2. All the major specifications of the sampler were determined experimentally in a large tank using three sizes of substrata and plastic pellets to represent invertebrates. The sampler performed accurately to a depth of at least 8 cm on substrata ranging from gravel (2–4 mm) to large stones (32–36 mm long).
3. The performance of the sampler was compared with that of a Ponar grab and Pearson el at. air-lift sampler at two sites on a large river and also with a Naturalist's dredge and a diver-operated Hess-Waters sampler at one of the sites where there were large stones up to 280 mm long. In terms of both mean taxa per sample and mean numbers m⁻², samples taken using the new air-lift sampler provided estimates comparable to or belter than those obtained with the other samplers.     

A folding artificial substratum sampler for use in standing water

A new easily retrieved folding artificial substratum sampler is described and its performance compared with that of trays in Cow Green Reservoir at a depth of 15–18 m.     

A comparative study of three air-lift samplers used for sampling benthic macro-invertebrates in rivers

SUMMARY. From 16 air-lift samplers described in the literature, three were selected for operation from a small boat: Mackey, Pearson et al. and Verollet & Tachet samplers. Random samples (number of sampling units n= 10) were taken in a large tank with a known number of dried peas, representing invertebrates, amongst stones of uniform size. Separate experiments were performed with three sizes of stones (modal sizes 2–4, 16–20 and 32–36 mm). Stratified-random samples (usually n= 10) were taken in rivers at lour sites with modal particle sizes of < 0.1 2–4. 32–128 and 64–128 mm. The samplers were compared with a Ponar grab in the tank experiments and the field, and with a Naturalist's dredge in the field. Rates of pumping at different air-flows were established for each sampler. Water-How increased with increasing air-How and increasing submergence of the riser-pipe. The Mackey sampler achieved the highest water-flow and lifted more substratum and larger stones (64–128 mm) than the other samplers. The Verollet & Tachet sampler had the lowest pumping rate and failed to lift stones > 8 mm long, whilst the Pearson et al. sampler, with an intermediate performance, lifted mud and stones < 32 mm long. In the tank experiments, the area from which the Mackey and Pearson et al. samplers collected peas varied with air-flow, operating time and type of substratum. The Maekey sampler over-sampled and the Pearson et al. sampler usually under-sampled their respective sampling areas, except the latter sampler at high air-flows gave approximately quantitative results comparable to those of the Ponar grab for peas on the surface of stones 16–20 mm. No sampler collected much at a depth of 3 cm on larger stones (32–36 mm), and the Verollet & Tachet sampler failed completely on all substrata. In field trials, the Mackey and Pearson et al. samplers provided good qualitative samples except on large stones (32–128mm). The Verollet & Tachet sampler lifted little material. The relative abundance of taxa often differed between samplers. Estimates of the number of invertebrates per m² differed widely between samplers except for the Pearson et al. and Ponar grab which gave similar quantitative results at three sites. Values were very low for the Verollet & Tachet sampler and Naturalist's dredge and always very high for the Mackey sampler which often grossly over-sampled its sampling area. Therefore, these three samplers cannot be considered as quantitative. The relationship between the variances and the means of samples of peas in the tank and most invertebrates in the field followed a power law with values of the exponent b in the range 1.13–2.51. The present study completes the evaluation of 14 samplers used to sample benthic macro-invertebrates in deep rivers, and the more important conclusions from the comparative studies of seven grabs, four dredges and three air-lift samplers are summarized in a table.     

The effect of substratum type, orientation and depth on the development of bacterial deep-sea biofilm communities grown on artificial substrata deployed in the Eastern Mediterranean

An increasing number of deep-sea studies have highlighted the importance of deep-sea biofouling, especially in relation to the protection of deep-sea instruments. In this study, the microbial communities developed on different substrata (titanium, aluminum, limestone, shale and neutrino telescope glass) exposed for 155 days at different depths (1500?m, 2500?m, 3500?m and 4500 m) and positions (vertical and horizontal) in the Eastern Mediterranean Deep Sea were compared. Replicated biofilm samples were analyzed using a Terminal Restriction Fragment Length Polymorphisms (T-RFLP) method. The restriction enzymes CfoI and RsaI produced similar total numbers (94, 93) of different T-RFLP peaks (T-RFs) along the vertical transect. In contrast, the mean total T-RF number between each sample according to substratum type and depth was higher in more samples when CfoI was used. The total species richness (S) of the bacterial communities differed significantly between the substrata, and depended on the orientation of each substratum within one depth and throughout the water column (ANOVA). T-RFLP analyses using the Jaccard similarity index showed that within one depth layer, the composition of microbial communities on different substrata was different and highly altered among communities developed on the same substratum but exposed to fouling at different depths. Based on Multidimensional Scaling Analyses (MDS), the study suggests that depth plays an important role in the composition of deep-sea biofouling communities, while substratum type and orientation of substrata throughout the water column are less important. To the authors' knowledge, this is the first study of biofilm development in deep waters, in relation to the effects of substratum type, orientation and depth.     

Assessment of two mesh sizes for interpreting life cycles, standing crop, and percentage composition of stream insects

Using Surber-type samplers and dip-net samplers, we assessed the efficiency of nets having pore sizes of 720 μm and 320 μm for determining standing crop and percentage composition of the stream fauna, and for collecting representative size-class specimens of Ephemeroptera and Plecoptera to be used in life-cycle studies. Except for one species, samples collected with either the 720-μm or 320-μm dip-net led to the same general inferences about the species' life cycle. Of fifty possible sample comparisons, there were twelve samples where the size-class frequencies of particular species collected in the 720-μm dip-net were significantly different from the size-class frequencies of the 320-μm dip-net; for five of these samples a deficit of large nymphs (> 5.0 mm) in the 320-μm net mainly contributed to the significant χ² values. On one date, we used double-bag samplers with both th e 720-μm and 320-μm nets attached to either the Surber or dip-net sampler. Approximately 50% of the insects by numbers passed through the 720 fxm mesh ofeach sampler, but only 5% by volume-biomass. Shape of the insect as well as body length was important in assessing mesh-size efficiencies. The 720-μm mesh of the double-bag dip-net sampler retained most of the Nemoura dnctipes (having stout appendages) and Epeorus longimanus (flattened) nymphs 2.0 mm in body length and larger; whereas most Baetis (streamlined) nymphs smaller than 3.0 mm and all Paraleuctra (needle-like shape) nymphs passed through the 720-μm mesh.     

A sampling device for the invertebrate fauna of aquatic vegetation

SUMMARY. A sampler designed to provide a quantitative estimate of the benthic invertebrates of littoral/sub-littoral zones dominated by Sphagnum moss is described. Data obtained from a small oligotrophic lake at a depth of 1 m using this sampler are presented. Optimum sample size was determined and samples comprising five sampling units were found to be adequate in terms of the number of invertebrate species present and their relative abundance. Similarity of such samples was greater than 90%.     

A quantitative sampler for collecting invertebrates associated with deep submerged vegetation

Only few of the numerous samplers for collecting invertebrate fauna associated with vegetation permit sampling at depths of more than approximately 0.5 m. This paper describes a sampler allowing collection of epifauna from submerged plants at a depth of up to approximately 2 m, growing in varied densities. The sampler is composed of two panels made of duralumin, connected on one side by means of piano-hinges. One of the panels has an opening covered with mesh, and the other is equipped with a cone-shaped net and detachable sample concentrator at its end. The sampler is coupled with a manipulator with a several meter extension for lowering the sampler under water, as well as for its opening, and closing. The initial assessment of the sampler efficiency, verified in beds of Potamogeton perfoliatus, provided similar results as two other, older and commonly used samplers. In comparison with the older devices, the sampler has the advantage of permitting collecting samples from greater depths. It also enables studying both the vertical and horizontal distribution of invertebrates within a plant patch.     

Effects of environment on electric field detection by small spotted catshark Scyliorhinus canicula (L.)

This study evaluated the influence of environment (substratum type and depth) on the electroreception capabilities of small spotted catsharks Scyliorhinus canicula in response to prey-simulating electric fields. In experiments where electric fields (applied current 15 μA) were presented beneath different substrata (sand, pebbles, rocks and control) it was found that search effort was not different between substrata or S. canicula sexes, however, both rates of turning and biting towards active electrodes were decreased over pebbles and rocks compared with sand and the control (no substratum). There was no significant effect of sex on turn and bite rates over any substrata. Electric fields were then presented beneath different depths of sand to examine the depth-limits of fish electroreception. Turn and bite rates were significantly lower at depths below 10 mm, with no bites towards electrodes made when they were >30 mm depth. Search effort was not found to be different between different burial depth treatments or between sexes. These results indicate substratum type and depth influences the ability of S. canicula to detect prey-simulating electric fields. This variation in electroreceptive performance may influence space use of sharks.     

The effect of substratum type,orientation and depth on the development of bacterial deep-sea biofilm communities grown on artificial substrata deployed in the Eastern Mediterranean

An increasing number of deep-sea studies have highlighted the importance of deep-sea biofouling, especially in relation to the protection of deep-sea instruments. In this study, the microbial communities developed on different substrata (titanium, aluminum, limestone, shale and neutrino telescope glass) exposed for 155 days at different depths (1500 m, 2500 m, 3500 m and 4500 m) and positions (vertical and horizontal) in the Eastern Mediterranean Deep Sea were compared. Replicated biofilm samples were analyzed using a Terminal Restriction Fragment Length Polymorphisms (T-RFLP) method. The restriction enzymes CfoI and RsaI produced similar total numbers (94, 93) of different T-RFLP peaks (T-RFs) along the vertical transect. In contrast, the mean total T-RF number between each sample according to substratum type and depth was higher in more samples when CfoI was used. The total species richness (S) of the bacterial communities differed significantly between the substrata, and depended on the orientation of each substratum within one depth and throughout the water column (ANOVA). T-RFLP analyses using the Jaccard similarity index showed that within one depth layer, the composition of microbial communities on different substrata was different and highly altered among communities developed on the same substratum but exposed to fouling at different depths. Based on Multidimensional Scaling Analyses (MDS), the study suggests that depth plays an important role in the composition of deep-sea biofouling communities, while substratum type and orientation of substrata throughout the water column are less important. To the authors’ knowledge, this is the first study of biofilm development in deep waters, in relation to the effects of substratum type, orientation and depth.     

Cumacean Lamprops pumilio—A New Species for the Sea of Japan

The treatment of materials collected in Srednyaya Bight (Peter the Great Bay) revealed in a sample taken on December 3, 1986, a female Lamprops pumilioZimmer with oostegites (3.5 mm long). The sample was obtained using an Okean bottom sampler (with the mouth area of 0.25 m²), at a depth of 10 m, from fine sand, at a temperature of –1.5°C.     

A long-term mesocosm study on the settlement and survival of juvenile European lobster Homarus gammarus L. in four natural substrata

To date, the natural substratum preferences of early benthic phase (EBP) European lobsters (Homarus gammarus) remain largely unknown. This study utilised a large scale mesocosm experiment to determine if the animal favours cobble ground, similar to its American counterpart (Homarus americanus), or has other substratum preferences. Postlarvae were provided with the choice of settling on four natural substrata: sand, coralline algae, mussel shell and cobble. Over a nine month period, the number and size of juveniles on each substratum was recorded, with loss of chelipeds used as an indication of social interaction. After a 30 day period, a non-random distribution of lobsters was observed on the four substrata. Juveniles were more abundant in substrata which provided pre-existing shelter in the form of interstitial spaces, i.e. cobble and mussel shell, than in sand or coralline algae. The survival of individuals from postlarvae to 30 day old juveniles ranged from 5 to 14% with surviving benthic recruits showing a clear mode at 6-8 mm carapace length (CL) in size distribution. The density of lobsters per m(2) of cobble remained relatively constant (18/m(2)) throughout the study period while the density of juveniles on mussel shell decreased significantly (35 to 5/m(2)). The size distribution of lobsters on each substratum also varied with time. By the conclusion of the trial, lobsters found in mussel shell had a mode of 8-10 mm CL within a range of 6-14 mm CL while those in cobble had a mode of 10-12 mm CL within a range of 8-24 mm CL. Overall, the results underline the importance of shelter-providing habitat such as cobble or crevice-type substrata to EBP European lobsters. They also confirm that for a shelter-dwelling animal such as a lobster, the physical structure of the habitat is a key factor in determining both the size and number of its inhabitants.     

Der Gesteinsabbau durch Ätzmuscheln an Kalkküsten

Zusammenfassung Verteilung und Populationsdichte der Ätzmuscheln werden bestimmt durch Wassertiefe und Neigungswinkel der Küste sowie besonders durch die Art des Substrates. Oolithische Kalke sind 2–3mal stärker besiedelt als Dolomit.Das Wachstum erfolgt schubweise zwischen Ruheperioden. Es läßt sich errechnen, daß die ersten 10 mm Längenwachstum nach 3 Jahren, die nächsten 10 mm nach 5 Jahren usw. erreicht werden, so daß sich für die größten Muscheln (80 mm) ein Alter von 80 Jahren ergibt.Dei Bohrtätigkeit hängt stark von der Beschaffenheit des Substrates ab. Die sog. Bohrrate betrug für 30 mm große Lithophagen in präparierten Steinen im Freiland 0,09-0,25 ml in 12 Wochen, das sind 0,5–1 ml bezogen auf 1 Jahr. Im Labor betrug sie nur ein Drittel davon.Die Ätzwirkung in die Tiefe hängt direkt von der Korngröße des Substrates ab. Die aus ihren Bindungen gelösten Kristalle werden als Pseudofaeces über die Wimperbahnen entfernt. Die Menge des produzierten Feinsediments kann ungefähr aus dem Lochvolumen berechnet werden.Der Küstenabbau durch Ätzmuscheln ist zwar auf relativ kleine Gebiete beschränkt, kann aber im steilen Declivium oolithischer Kalke in 1–2m Tiefe mehr als 40 cm/m² in 1000 Jahren betragen.

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Summary The depth of water and the inclination angle of the coast and, in particular, the kind of substratum determine the distribution and population density of date mussels. Oolitic limestones are twice to three times as highly populated as dolomites.The growth takes place in stages, between periods of rest. 10 to 20% ofLithophaga lithophaga having a length of about 30mm grew by 0.4 to 3.1 mm in the period of 12 weeks in the substratum. 1 to 2% of mussels with a size of 50 to 60 mm grew by 0.1 to 1 mm outside the substratum. Small mussels grew more frequently and to relatively greater extent than big ones. The first 10 mm of growth in length occurs in the first three years, the next 10 mm after 5 years, etc. so that the biggest mussels (80 mm) will be about 80 years old.The boring activity depends on the condition of the animal and, largely, on the kind of substratum. The boring rate on prepared stones in the open was 0.09 to 0.25 ml in 12 weeks forLithophaga lithophaga with a size of 30mm, that is 0.5 to 1 ml per year. In the laboratory, this amounted to only a third.The depth of the etching effect depends on the granule size in the substratum. The crystals released from the substrate are removed as pseudofeces via the ciliary epithelium. The amount of the fine sediment may be calculated roughly from the volume of the hole.Finally, an attempt is made to apply the experimental findings to the conditions prevailing in the sampling area. It is true that the destruction of the coast by date mussels is restricted to relatively small areas, but it may amount to more than 40 cm/m² at a depth of 1 to 2 meters and continue for a period of 1000 years on the steep slope of oolitic limestones.

     

Impact of date mussel harvesting on the rocky bottom structural complexity along the Istrian coast (Northern Adriatic, Croatia)

A survey of 50 km of the coast, including islands, rocks and offshore shallows, in the region of Rovinj (North Adriatic, Croatia) showed that the harvesting of the European date mussel Lithophaga lithophaga (L., 1758) is restricted to inclined, approximately vertical, surfaces. Usually, a stratum of rock, varying from several to about ten cm is removed by hammering, resulting in the complete eradication of sessile organisms. The damage was heavily widespread up to 6 m depth (47% of the total inclined surfaces for the whole area). Between 6 and 14 m depth, the damage was much less (14% from 6 to 10 and 7% from 10 to 14 m depth); below this depth, no damage was observed. The damage patterns coupled with the date mussel distribution, which was constrained by the nature of the substratum (limestone or dolomitic limestone), the general architecture of the rocky bottom and the depth. The structural complexity of inclined surfaces was quantified by 5 indices previously used in biota-substratum interaction studies. Heights of 11 pins placed 3 cm apart in a profile gauge were measured to determine the standard deviation of heights, the coefficient of variation of heights, the sum of squared heights, chain and tape ratio and circular variance of angles. Comparisons of these indices, among damaged and intact surfaces in different habitats and sites within habitats, showed a substantial decrease in complexity of the rocky substratum due date mussel harvesting. Thus, this human disturbance can permanently affect rocky shallow water communities as physical features of the substratum may exert strong effects on species.     

Evaluation and use of a diffusion-controlled sampler for determining chemical and dissolved oxygen gradients at the sediment-water interface

Field and laboratory evaluations were made of a simple, inexpensive diffusion-controlled sampler with ports on two sides at each interval which incorporates 0.2-m polycarbonate membrane to filter samples in situ. Monovalent and divalent ions reached 90% of equilibrium between sampler contents and the external solution within 3 and 6 hours, respectively. Sediment interstitial water chemical gradients to depths of tens of centimeters were obtained within several days after placement. Gradients were consistent with those determined from interstitial water obtained by centrifugation of adjacent sediment. Ten milliliter sample volumes were collected at 1-cm intervals to determine chemical gradients and dissolved oxygen profiles at depth and at the interface between the sediment and water column. The flux of dissolved species, including oxygen, across the sediment-water interface can be assessed more accurately using this sampler than by using data collected from benthic cores.     

How to leave or stay on the substratum when you can’t swim? Evidence of the role of mucus thread secretion by postlarvae of Pectinaria koreni (Malmgren) in still water and flume experiments

Through an experimental approach we investigate the role of mucus secretion in postlarvae of Pectinaria koreni (tubicolous polychaete) on their ability to drift within the benthic boundary layer or to stay at the water–substratum interface. Fall velocity measurements were conducted with either living or dead postlarvae which were allowed to sink into a 2 m long Plexiglas cylindrical chamber. Five groups of increasing size-classes were tested ranging from the very first benthic stage (1 mm < Tube_length < 2 mm: membranous tube present accounting for more than 75% of the total tube length) to older stages (6 mm < Tube_length < 10 mm: membranous tube absent). We used these results to propose the first estimates of dispersal distances by several post-larval stages secreting mucus or sinking passively through the water column. Experiments were carried out in the HYCOBENTHOS flume to determine values of critical shear velocity (u _*c) inducing bedload transport and further resuspension of postlarvae of increasing sizes. The influence of mucus secretion by recruits on their ability to stay or quit a ‘suitable’ substratum was investigated by using either living or dead individuals. Results showed that: (a) the ability to secrete mucus rapidly is limited to the younger stages; (b) fall velocity of postlarvae is drastically lowered by mucus secretion (5 orders of magnitude) and is higher for the older stages; (c) dead recruits behave similarly to ‘passive’ recruits; (d) horizontal distances of drift dispersal may be considerable (up to 800 m for a single 22 min trip); (e) mucus secretion may be used by the postlarvae to anchor themselves to the substratum. Cost-benefit of using the mucus secretion as a tool for recruitment and the related spatial scales are discussed.     

The Stone Brusher, a New Sampler for Submerged Epilithic Material in Shallow Streams and Lakes

The Stone Brusher is designed to take qualitative or semi-quantitative samples of material attached to stones at 7–50 cm depth in running or stagnant waters. The epilithic material is dislodged from the stone surface with a rotating brush enclosed in a chamber and the material is drawn up directly into the sample bottle with an air-cylinder. The operator takes a sample quickly and without putting hands into the water. The sampling area is about 28 cm². The sampler is made of plastic, stainless steel and aluminium and weighs 3.1 kg. The equipment is robust and easily handled and it is constructed to meet the demand for standardized sampling for research and environmental monitoring and to improve working conditions for sampling personnel. The equipment allows sampling from bedrock and large stones that cannot be lifted from the bottom and it can be used for reliable sampling also in fast-flowing streams where the dislodged material is easily flushed away. Using Near-Infrared Spectroscopy and diatom analyses, this new sampler is evaluated in comparison to the recognized toothbrush method, which indicates that the Stone Brusher reduces sampling variability compared with the toothbrush method.     

Visiting the hyporheic zone: young Atlantic salmon move through the substratum

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A comparative study of seven grabs used for sampling benthic macroinvertebrates in rivers

SUMMARY. After considering the large number of grabs described in the literature, seven grabs of weight < 25 kg were chosen for manual operation from a small boat: Van-Veen grab, weighted and unweighted Ponar grabs, Friedinger version of the Petersen grab, Dietz-La Fond mud-snapper, pole-operated Birge-Ekman grab and pole-operated Allan grab. Random samples (number of sampling units n= 10) were taken in a large tank with a known number of 2-mm cylindrical plastic pellets amongst stones of uniform size. Separate experiments were performed with four sizes of stones (model ranges: 2–4 mm, 8–16 mm, 16–32 mm, 32–64 mm). Stratified random samples (n= 10) were taken in rivers and the modal particle sizes at four sites were 0.004–0.06 mm, 0.5–2 mm, 16–64 mm and 64–128 mm. All grabs usually took a representative sample of the substratum at each site with no strong bias towards a particular particle size. The general performance of the Friedinger, Dietz-La Fond and Allan grabs was poor, except on a muddy bottom, with frequent failure to operate, small samples of substratum and a mean depth of penetration < 3 cm in all substrata except mud for the Dietz-La Fond and Allan grabs. The Van-Veen and Birge-Ekman grabs sampled to a mean depth < 3 cm in mud and fine gravel (2–4 mm), but the Birge-Ekman jammed frequently in fine gravel. Both Ponar grabs operated well and sampled to a mean depth ≥ 5 cm in mud and fine gravel, > 3 cm when small stones (8–16 mm) were present and 2 cm (weighted Ponar only) when larger stones (> 16 mm) were present in a gravel bottom. The mean depth was <0.8 cm for all grabs when larger stones (>16 mm) were predominant on the bottom. In the tank experiments with pellets, the efficiencies for the total catches of the Friedinger, Dietz-La Fond and Allan grabs were low with values <45% for fine gravel (2–4 mm), < 22% for small stones (8–16 mm) and <5% for a substratum of larger stones (>16 mm). If 50% is the minimum acceptable efficiency, then the Ponar, Van-Veen and Birge-Ekman grabs were adequate for fine gravel, only the two Ponar grabs were adequate for small stones and no grabs were adequate for sampling a substratum of larger stones (>16 mm). In field trials, the relative abundances of major taxa were similar for most grabs at each site; Friedinger and Dietz-La Fond grabs were the major exceptions. In terms of both mean number of taxa and mean number of invertebrates m^?2 the Ponar, Birge-Ekman and Allan grabs performed well on the predominantly muddy substratum at site 1, but only the weighted Ponar grab performed adequately on the predominantly gravel bottom with some large stones (>16 mm) at site 2. All grabs performed badly when larger stones (>16 mm) were predominant on the bottom (sites 3, 4). The relationship between the variances and means of the samples taken with each grab followed a power law for the catches of pellets in tank experiments, and for major taxa and total numbers at each site in field trials. Values of exponents in the power law lay within the range 1.14–2.34. The coefficient of variation was also frequently related to the sample mean and was an unreliable statistic for comparing the precision of grabs.     

Modelling sponge species diversity using a morphological predictor: a tropical test of a temperate model

The contribution of sponges to marine surveys is often underestimated due to problems of identification, synonymous species and limited numbers of specialists in the field. Bell & Barnes (2001) illustrated how sponge morphological diversity (diversity of body forms) might be used as a predictor of sponge species diversity and richness. This study investigated these relationships at six tropical West Indian Ocean localities in a number of habitat types. These habitats included tropical coral reefs, soft substratum (seagrass, mangrove and sand), caves and boulders. Sampling was undertaken at three depth zones in coral reef habitats only (intertidal, 10–15 m and 20–25 m), with the other habitats sampled in less than 10m of water. Species diversity and richness were significantly correlated (P < 0.05) with morphological diversity at all localities and depths in coral reef and soft substratum habitats. However, no significant correlation was found between these variables in cave or boulder habitats. The slope of the linear regression found between morphological diversity and species diversity did not significantly differ between coral reef, soft substratum and temperate reef (data taken from Bell & Barnes 2001) habitats. Similarly coral reefs showed the same relationship between morphological diversity and species richness as temperate reefs, however the relationship between morphological diversity and species richness was significantly different at both habitats compared with soft substratum environments. Sponge morphological diversity therefore may be more useful as a predictor of sponge species diversity, rather than species richness, as the former relationship is common between more habitats than the latter.