Testing a depth‐based Habitat Classification System against reef fish assemblage patterns in a subtropical marine park

• 1. The Solitary Islands Marine Park (SIMP) in New South Wales (NSW), Australia, has strong cross‐shelf patterns of reef fish assemblages on shallow reefs (<25 m). While the SIMP also contains reef at depths of up to 75 m, marine communities below 25 m are poorly described. The Habitat Classification System (HCS) used for planning the arrangement of zones in this marine park included three depth categories for reef: shallow (<25 m); intermediate (25–60 m); and deep (>60 m). However, these had not been tested to determine if they adequately reflect biotic patterns.
• 2. Using baited remote underwater video (BRUV), fish assemblages were surveyed at 56 sites spread across shallow, intermediate, and deep reefs within the SIMP to examine spatial variation between depth categories. Relationships between assemblage patterns, depth, and four additional factors considered likely to affect assemblage patterns (distance from shore, reef type, dominant benthos, and latitude), were subsequently explored using multivariate statistical methods.
• 3. Reef fish assemblages differed significantly among the depth categories. Assemblage patterns for fish were strongly correlated with depth and moderately correlated with the dominant benthic assemblage. Correlations with the other factors were generally weak. Three distinct assemblages occurred on reefs <25 m, 25–50 m and >50 m. Shallow (<25 m) reefs also displayed strong cross‐shelf patterns, supporting the results from other studies. Weaker cross‐shelf patterns were evident at intermediate depths (25–50 m).
• 4. Depth‐based and cross‐shelf categories are clearly fundamental components for a HCS that will adequately represent reef fish assemblages for conservation planning in the SIMP. Further refining the depth criteria for the intermediate/deep boundary (to 50 m) improves this representation. Further research is required to determine the wider application of the refined HCS to other marine parks in NSW and to determine how well it represents other components of biodiversity. Copyright © 2011 John Wiley & Sons, Ltd.

     

MAGNETIC RESONANCE IMAGING CONTRAST ENHANCEMENT OF EXTRA‐OCULAR MUSCLES IN DOGS WITH NO CLINICAL EVIDENCE OF ORBITAL DISEASE

Enhancement of extra‐ocular muscles has been reported in cases of orbital pathology in both veterinary and medical magnetic resonance imaging. We have also observed this finding in the absence of orbital disease. The purpose of this retrospective study was to describe extra‐ocular muscle contrast enhancement characteristics in a group of dogs with no known orbital disease. Magnetic resonance images (MRI) from dogs with no clinical evidence of orbital disease and a reportedly normal MRI study were retrieved and reviewed. Contrast enhancement percentages of the medial, lateral, ventral, and dorsal rectus muscles were calculated based on signal‐to‐noise ratios that were in turn determined from hand‐traced regions of interest in precontrast, immediate postcontrast and 10‐min postcontrast scans. Comparison measurements were made in the pterygoid muscle. Contrast enhancement of the extra‐ocular muscles was observed in all patients (median contrast enhancement percentage 45.0%) and was greater than that of pterygoid muscle (median contrast enhancement percentage 22.7%). Enhancement of the extra‐ocular muscles persisted 10 min after contrast administration (median contrast enhancement percentage 43.4%). Findings indicated that MRI contrast enhancement of extra‐ocular muscles is likely normal in dogs.     

Metallothionein induction in cultured fibroblasts and liver of a marine flatfish,the turbot,Scophthalmus maximus

Intraperitoneal injection of turbot with Cd induced the synthesis of a low molecular weight hepatic Cd-binding protein and a 500bp mRNA, which hybridised to a plaice metallothionein (MT) cRNA probe. The Cd-binding protein displayed cross-reactivity in a competitive ELISA with antiserum raised against rainbow trout MT and had the characteristic amino acid composition, metal stoichiometry and spectral characteristics of a Class I MT. Only one isoform was apparent on ion exchange chromatography. Southern blot analysis of DNA cleaved with four restriction enzymes suggested that only a single MT gene is present in turbot.In an established turbot fibroblast cell line, Cd induced MT mRNA and MT levels in a dose and time-dependent manner. MT was also induced by Cu, Hg and Zn but not Pb exposure. Physiological concentrations of glucocorticoids and sex hormones did not induce MT synthesis, although at high concentrations a positive response to corticosterone, dexamethasone, hydrocortisone or progesterone was observedin vitro indicating the possible presence of a functional steroid regulatory element in the fish MT gene.Abbreviations used AMP adenosine monophosphate - CHSE chinook salmon embryo - DMSO dimethyl sulphoxide - HPLC high performance liquid chromatography - KB kenacid blue - MT metallothionein - Mr molecular weight (kDaltons) - NR neutral red - PEG polyethylene glycol - RTH rainbow trout hepatoma - SDS sodium dodecyl sulphate - SSC 0.15M NaCl, 0.015M sodium citrate - TF turbot fibroblast     

The type of activated carbon determines how much dissolved organic carbon is removed from artificial seawater

Four granular activated carbons (GACs) made of different materials were tested for removal of dissolved organic carbon (DOC) from artificial seawater of a recirculated aquarium. After 70 days in a continuous flow experiment, comparative removal data (grams of GAC required to remove 1 g of DOC) were coconut shell (491), hardwood (84·4), anthracite (837) and bone char (383), indicating the superior performance of hardwood. Scanning electron microscopy showed that microbial colonization of a sample material (hardwood) was slight and occurred exclusively at the surface. Biological enhancement of GAC was considered to be unimportant as a mechanism for DOC removal.     

Effects of oxygen supersaturation and temperature on juvenile greenlip, Haliotis laevigata Donovan, and blacklip, Haliotis rubra Leach, abalone

Growth and survival of juvenile greenlip (39.03 (SD 3.80) mm (n=524)) and blacklip (31.92 (SD 4.19) mm (n=531) abalone were investigated at high dissolved oxygen levels (95–120% saturation) between 17 and 19°C. Abalone were fed the same artificial diet and each species was contained in groups of approximately 30 individuals within triplicate tanks for each of six treatments and were exposed to flow through water adjusted to give experimental conditions for up to 75 days. Blacklip abalone held at 16.9°C and 97% oxygen saturation grew in shell length significantly faster than all other treatments of blacklip abalone held at 19°C, and significantly faster than blacklip abalone maintained at 111% oxygen saturation and 17.5°C. Both temperature and oxygen saturation significantly affected the survival of this species. Blacklip abalone held at 19°C had significantly lower survival for both 96% oxygen saturation and 120% oxygen saturation, compared with blacklip abalone maintained at either 110% oxygen saturation and 19°C, or for any 17°C treatment. No significant differences were noted for greenlip abalone within the range tested in terms of growth rate, food consumption rate or survival, indicating that greenlip abalone tolerated these conditions better than did blacklip abalone.     

Marine research,resources and conservation in the Azores

• 1 A history of marine research on the Azores is outlined. Until two decades ago most oceanic and littoral marine studies had been carried out by foreign scientists. Studies by Azorean scientists started to increase in the early 1980s when the University of the Azores was created.
• 2 Ocean circulation in this part of the Atlantic is described as a background for biogeography and diversity. The picture emerges that Azores is a ?meeting point’? for shallow water marine fauna and flora of different origins.
• 3 The species composition of one of the best studied groups of organisms, the fish, is compared between locations in the northeastern Atlantic. The work on fish is also compared with other well studied groups (algae and hydroids) to highlight the interest of the Azores as a natural biogeographical experiment.
• 4 Studies of marine resources began less than two decades ago. The development of demersal fisheries is described focusing on the switch from small-scale artisanal fishing to more commercial fisheries.
• 5 Conservation of species and legislation in force for molluscs, crustaceans, fishes, marine turtles, seabirds and marine mammals are summarized.
• 6 Protected marine areas already designated are defined, as well as new areas recommended.
• 7 The paper concludes with a discussion of current threats and future management strategies.

     

PROBIT analysis predicts hatching rates of brine shrimp Artemia sp. cysts

Thirty replicates of San Francisco Bay brine shrimp Artemia sp. cysts from one lot were weighed to 0·01 mg. The mean mass of a single cyst was 2·597 μg (±0·040 μg, 95% confidence level). Batches of 1 g from the same lot were hatched in the laboratory, and fraction hatched versus time data were fitted to a nonlinear curve using PROBIT analysis. Median time of hatch was 24·8 h with a standard error of ±3·92 h. Cysts and nauplii in 1-ml aliquots were pipetted at regular intervals and counted under a dissecting microscope. The number of cysts pipetted at the beginning of the experiment was 19% less than estimates based on the known number per volume of hatching medium, indicating that hatching data derived from pipetting procedures may contain large sampling errors. PROBIT analysis allows fraction hatched to be predicted when a particular lot of cysts is hatched under controlled conditions.     

Habitat mapping in the Caribbean for management and conservation: Use and assessment of aerial photography

• 1 The nature and distribution of the coastal and shallow marine habitats of Anguilla in the Caribbean were examined using aerial photography coupled with extensive ground truth information.
• 2 The objective was to develop an accurate method of marine habitat mapping for the analysis of the marine ecosystem in order to develop a procedure for marine and coastal resource management.
• 3 This paper describes the method which was adopted as well as the biological results.
• 4 It is concluded that the management and sustainable use of the natural resources may be improved as a result of accurate habitat mapping.