The Tectonic and Geological Environment of Coastal South America.- 1 The Gulf of Honduras.- 2 The Coastal Lagoon Cienaga Grande De Santa Marta, Colombia.- 3 The Maracaibo System, Venezuela.- 4 The Orinoco River Delta, Venezuela.- 5 The Itamaraca Estuarine Ecosystem, Brazil.- 6 The Abrolhos Reefs of Brazil.- 7 The Cabo Frio Upwelling System, Brazil.- 8 Baia de Guanabara, Rio De Janeiro, Brazil.- 9 The Lagoon Region and Estuary Ecosystem of Cananeia, Brazil.- 10 The Subtropical Estuarine Complex of Paranagua Bay, Brazil.- 11 The Convergence Ecosystem in the Southwest Atlantic.- 12 The Patos Lagoon Estuary, Brazil.- 13 The Rio de la Plata Estuary, Argentina-Uruguay.- 14 The Bahia Blanca Estuary, Argentina.- 15 The Sand Beach Ecosystem of Chile.- 16 The Peruvian Coastal Upwelling System.- 17 The Gulf of Guayaquil and the Guayas River Estuary, Ecuador.- 18 The Estuary Ecosystem of Buenaventura Bay, Colombia.- 19 Eastern Pacific Coral Reef Ecosystems.- 20 The Tropical Pacific Coast of Mexico.- 21 Upwelling and Lagoonal Ecosystems of the Dry Pacific Coast of Baja California.- 22 The Colorado River Estuary and Upper Gulf of California, Baja, Mexico.- A Summary of Natural and Human-Induced Variables in Coastal Marine Ecosystems of Latin America.

Coastal marine ecosystems of Latin America.

Benthic faunal abundance, diversity, and biomass were examined in the northeastern Chukchi Sea to determine factors influencing faunal distribution. Four taxon-abundance-based benthic station groups were identified by cluster analysis and ordination techniques. These groups are explained, using stepwise multiple discriminant analysis, by the gravel-sand-mud and water content of bottom sediments, and the organic carbon/nitrogen (OC/N) ratio. In contrast to previous benthic investigations in the northeastern Bering and southeastern Chukchi Seas, faunal diversity between inshore and offshore regions in our study area were not related to differences in sediment sorting. Instead, regional diversity differences in the northeastern Chukchi Sea were related to greater environmental stresses (e.g. ice gouging, wave-current action, marine-mammal feeding activities) inshore than offshore. The presence of a high benthic biomass north of Icy Cape in the vicinity of Point Franklin and seaward of a hydrographic front is presumably related to an enhanced local depositional flux of particulate organic carbon (POC) in the area. We postulate that POC-rich waters derived from the northern Bering and northwestern Chukchi Seas extend to our study area and the flux of the entrained POC provides a persistent source of carbon to sustain the high benthic biomass. Annual POC enrichment of the coastal region north of Icy Cape is reflected by the great abundance of amphipods and other invertebrates present there and the concentration in summer of walrus Odobenus rosmarus djvergens and gray whales Eschrichtius robustus that feed on these invertebrates. This study demonstrates that there can be high standing stocks of benthos in arctic regions with relatively low annual primary production if local carbon is augmented by POC advected from highly productive areas.

/pdf/the-northeastern-chukchi-sea-benthos-environmental-21sahdv2nw.pdf

The northeastern Chukchi Sea: benthos-environmental interactions

Application of Bryozoan zoarial growth-form studies in facies analysis of non-tropical carbonate deposits in New Zealand

1. Benthic invertebrate bycatch was collected during trawling for orange roughy (Hoplostethus atlanticus) at water depths of 662–1524 m on the northern and eastern Chatham Rise, New Zealand, in July 1994. Seventy-three trawl tows were examined, 49 from ‘flat’ areas and 24 from two groups of ‘hills’ (small seamounts). Benthos was recorded from 82% of all tows.



 2. Some 96 benthic species were recorded including Ophiuroidea (12 spp.), Natantia (11 spp.), Asteroidea (11 spp.), Gorgonacea (11 spp.), Holothuroidea (7 spp.), and Porifera (6 spp.).



 3. Cluster analysis showed the bycatch from flats and hills to differ significantly. Dominant taxa from flats were Holothuroidea, Asteroidea and Natantia; whereas taxa most commonly recorded from hills were Gorgonacea and Scleractinia. Bycatch from the two geographically separate groups of hills also differed significantly.



 4. The largest bycatch volumes comprised corals from hills: Scleractinia (Goniocorella dumosa), Stylasteridae (Errina chathamensis) and Antipatharia (?Bathyplates platycaulus). Such large sessile epifauna may significantly increase the complexity of benthic habitat and trawling damage may thereby depress local biodiversity. Coral patches may require >100 yr to recover.



 5. Other environmental effects of deep-water trawling are briefly reviewed.



 6. There is an urgent need to assess more fully the impact of trawling on seamount biotas and, in consequence, possible conservation measures.



© 1997 John Wiley & Sons, Ltd.

Benthic invertebrate bycatch from a deep‐water trawl fishery, Chatham Rise, New Zealand

The demersal fish stocks in southern Brazil were assessed from landings and catchper-unit effort data trends between 1975 and 1994, available information on the life history patterns, and population dynamics of the most important species. The fishing gears, mostly otter and pair bottom trawls in the 1970s, diversified towards double-rig trawls for fish and shrimp and bottom gill nets in the mid 1980s, and bottom longlines in the upper slope in the early 1990s. There were also some less successful attempts with traps for fish and crabs. The demersal fisheries are more intensive in winter when migratory species move northward, associated with the seasonal displacement of the western boundary of the Subtropical Convergence. Landings between 1975 and 1994 were mostly of sciaenid fishes (>70%) and elasmobranchs (10%) and oscillated around 59 000 t. There was not a decrease in total landings but a shift from more to less exploited stocks. Since 1989, 4% of the landings came from depleted stocks of Pagrus pagrus (L.), Netuma barba (Lacepede), Pogonias cromis (L.) and Rhinobatos horkelli (Muller & Henle); 37% from overexploited stocks: Micropogonias furnieri (Desmarest), Paralichthys patagonicus Jordan, Squatina guggenheim Marini, and Galeorhinus galeus (L.); 24% from heavily exploited stocks of Umbrina canosai Berg, and Macrodon ancylodon (Bloch & Schneider); and 35% of Cynoscion guatucupa (Cuvier) and small stocks with unclear status. The demersal fisheries are virtually unmanaged and future landings are expected to decrease if fishing pressure remains high. Effective management will require the participation of all three countries in the region because most of the stocks fished in southern Brazil are shared with Uruguay and Argentina.

/pdf/present-state-and-perspectives-for-the-southern-brazil-shelf-2sipt03b45.pdf

Present state and perspectives for the southern Brazil shelf demersal fisheries

A survey was made of epibenthic macrofauna on the continental shelf and upper continental slope (canyons) off the Otago Peninsula. Three major bottom faunas, recognised by site‐grouping and species‐grouping classification, are related to depth zones, sediment types, and water masses. An inner shelf benthos, to a depth of about 30 m, is associated with sand and neritic water. A mid‐shelf to uppermost slope benthos, extending in places to 360–370 m, occurs on gravelly sediments in the path of the Southland Current (subtropical in origin), and a submarine canyon benthos, best developed on muddy sediments below about 450 m, is probably mainly influenced by Antarctic Intermediate Water. Bryozoans, especially the cyclo‐stome Filicea elegans, dominate the mid‐shelf where there is pebbly substratum for colony attachment, little fine sediment deposition, and continuous flow of the Southland Current.

Epibenthic macrofauna off southeastern New Zealand and mid‐shelf bryozoan dominance

Benthic macrofauna of the continental shelf off Otago Peninsula, south-eastern New Zealand (45°51′S, 170°52′E) was surveyed by dredge sampling during 1973–1975. Numerical classification (Canberra metric coefficient and flexible sorting) was used to produce site groups and species groups, and three major benthic communities were recognised: a shallow-water (14–25 m) fauna inhabiting well-sorted fine sand, a mid-shelf fauna (concentrated in the depth range 50–76 m) associated with sediments containing the greatest proportions of gravel and siltclay, and a predominantly sand-bottom fauna occurring mainly on the outer shelf (87–150 m). All station groups were dominated numerically by polychaetes (mean of 36·6–56% of individuals) with Mollusca (13·8–25%) or Crustacea (12·1–19·4%) the next most abundant group. The inshore sand fauna was the most distinct, characteristic elements being the trochid gastropod Antisolarium egenum , an amphipod of the genus Hippomedon and dense patches of the spionid polychaete Spiophanes bombyx . Diagnostic species of the mid-shelf mixed sediments were Lepidonotus jacksoni , Psammolyce antipoda , Lumbrineris brevicirra and Phyllamphicteis foliata (Polychaeta), Terenochiton otagoensis , Micrelenchus caelatus caelatus , Maoricolpus roseus roseus and Zegalerus tenuis (Mollusca), Ampelisca chiltoni (Amphipoda) and Amphipholis squamata (Ophiuroidea). Outer shelf sand stations were faunally less distinct, but among the more characteristic species were Euthalenessa fimbriata , Sigalion sp. and Euchone sp. (Polychaeta) and Gari stangeri (Bivalvia). Several abundant species were widely distributed among station groups, notably Nephtys macroura , Lumbrineris magalhaensis , Phyllochaetopterus socialis and Owenia fusiformis (Polychaeta) and Nucula nitidula and Tawera spissa (Bivalvia). Free-living lunulitiform Bryozoa of the genus Otionella were a characteristic component of inner and outer shelf sand faunas, and their inshore penetration probably marks the outer limit of a turbulent zone. Species diversity (Margalef's d ) varied markedly across the shelf and appeared to be related primarily to the degree of sediment heterogeneity. Mixed sediments of the middle shelf were particularly rich in species.

Continental shelf benthos off Otago Peninsula, New Zealand

Objective To compare the dynamic insulin secretion and sensitivity
 test (DISST) with the euglycaemic clamp in individuals undergoing open
 Roux-en-Y gastric bypass (RYGB) surgery prior-to and one month after
 surgery. Methods Insulin sensitivity in individuals with obesity undergoing
 RYGB was studied with DISST and a euglycaemic hyperinsulinaemic clamp. Results Eleven participants, including nine females, mean(SD) age
 51.2 (12.1) yrs, with a preoperative BMI of 48.7(9.5)kg/m2
 were studied. Weight reduced from a mean (SD) of 133.8 (29.8) kg to
 123.8 (28.9) kg post-surgery (p<0.001). The mean (SD) insulin
 sensitivity index (ISI-DISST) was 3.07×10−4 (2.18) L.pmol−1.min−1
 preoperatively and 2.36
 ×10−4 (0.78)L.pmol−1.min−1
 postoperatively (p=0.37). The mean(SD) clamp ISI was 2.14
 ×10−2 (1.80) mg.L.kg−1.min−1.pmol−1
 and
 2.00×10−2.(0.76) mg.L.kg−1.min−1.pmol−1
 postoperatively (p=0.86). Correlation between ISI-DISST and
 ISI-Clamp preoperatively was r=0.81(95%CI 0.37-0.95) and
 post-operatively r=0.47(95%CI 0-0.88). Bland-Altman analysis
 demonstrates systematic bias between the two tests, where DISST
 underestimated insulin sensitivity compared with the clamp by
 0.96×10-2.mg.L.kg−1.min−1.pmol−1
 (95%CI -2.24 to 0.32). Conclusions There was a strong correlation between DISST and the
 clamp preoperatively and DISST can be used to estimate insulin sensitivity
 in individuals with morbid obesity. After RYGB surgery, DISST had a weaker
 correlation with the clamp suggesting the fundamental physiological
 determinants of insulin sensitivity being measured by each method change in
 different ways with changes in glucose homeostasis following RYGB
 surgery.

Assessment of the Dynamic Insulin Secretion and Sensitivity Test (DISST) Pre and Post Gastric bypass Surgery.

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Epibenthic macrofauna off southeastern New Zealand and mid‐shelf bryozoan dominance

Continental shelf benthos off Otago Peninsula, New Zealand

Assessment of the Dynamic Insulin Secretion and Sensitivity Test (DISST) Pre and Post Gastric bypass Surgery.