Solenosmilia Variabilis Research Articles

Cold‐water coral habitats on seamounts: do they have a specialist fauna?

ABSTRACTAim The large biogenic structures formed by colonial cold‐water scleractinian corals provide valuable habitat for marine invertebrates on seamounts and the continental slope of all world oceans. These patchily distributed long‐lived structures are easily damaged by several human activities, particularly bottom trawling for fish, and are potentially vulnerable to ocean acidification caused by climate change. Consequently, an important conservation question is whether these structures support a specialized invertebrate fauna restricted to these habitats. Here we investigate the relationship between structures formed by the coral Solenosmilia variabilis and its associated ophiuroid (brittlestar) fauna, one of the dominant components of deep‐sea ecosystems.Location Seafloor habitat around Southern Australia, New Zealand, and the Macquarie Ridge from 35 to 53° S and 117° E–176° W, 500–1500 m depth.Methods Data were derived from samples collected by numerous scientific expeditions to the study region. Because these samples were collected using a variety of gear and effort, a two‐step approach was used. First, the largest consistently collected data set (73 ophiuroid species from 59 samples) was assembled for multivariate analysis. ANOSIM was used to test for differences in ophiuroid community composition between Solenosmilia and non‐Solenosmilia habitat on seamounts and the continental slope, and SIMPER was used to identify species that characterized Solenosmilia habitat. Second, these results were validated against all known data to ensure that these characteristic species had not been found in non‐Solenosmilia habitat elsewhere.Results The ophiuroid assemblages from Solenosmilia habitat were distinct from those found on other habitats on the continental slope and offshore seamounts across the study region. Although a suite of ophiuroid species characterized Solenosmilia habitat, most have also been collected from dead coral or other rubble, suggesting a physical rather than biological association between the coral matrix and its associated invertebrate fauna.Main conclusions Despite the lack of an exclusive ophiuroid–coral relationship, cold‐water scleractinian coral remains the principal habitat for a number of ophiuroid species across southern Australia and New Zealand. The slow growth rate of the coral and the low dispersal potential of some associated species suggest that recovery of damaged cold‐water coral assemblages will be a long‐term process.

A new genus and species of hermit crab (Decapoda: Anomura: Paguridae) from seamounts off south-eastern Tasmania, Australia

McLaughlin, P.A. 2003. A new genus and species of hermit crab (Decapoda: Anomura: Paguridae) from seamounts off south-eastern Tasmania, Australia. Memoirs of Museum Victoria 60(2): 229‐236. A new and highly variable species, representing a new genus of hermit crabs, is described and illustrated. In addition to the morphological changes in shape and armature of the chelipeds associated with growth in Bythiopagurus macrocolus, gen. nov., sp. nov., this species exhibits a singular development of the left chela that may be an adaptation to its specialised habitat among colonies of the stony coral Solenosmilia variabilis Duncan. The similarities seen among the genera Bythiopagurus, gen. nov., Michelopagurus McLaughlin and Icelopagurus McLaughlin appear the be superficial and convergent; Bythiopagurus appears phylogenetically related to the Pylopaguropsis group of genera characterised by 13 pairs of bi- or quadriserial gills.

Analysis of bycatch in the fishery for orange roughy, Hoplostethus atlanticus, on the South Tasman Rise

Government fisheries observers made detailed records of the catch weights of all species caught on 545 trawls between October 1997 and August 2000 in the South Tasman Rise orange roughy (Hoplostethus atlanticus) fishery. Bycatch ratios, the ratio of bycatch weight to tow duration, were derived from these data and used to make estimates of total annual bycatch for several species groups. Bycatch ratios based on tow duration were chosen over ratios based on orange roughy catch weights after comparing the coefficients of variation (c.v.) of sets of trial data. Bycatch ratios and total bycatch were estimated for three species of oreos (Oreosomatidae), corals and all other bycatch species combined, for the fishing years from 1997–1998 to 2000–2001. Total oreo bycatch dropped from about 7400 t to less than 350 t during this time. These estimates agreed well with recorded oreo landings data for three of the four years. There was a considerable bycatch of corals, with both the bycatch ratio and the total bycatch reducing during the period examined, the latter from about 1750 t to 100 t per year. The coral bycatch comprised a large number of species, but was dominated by the reef-forming stony coral Solenosmilia variabilis. Annual bycatch of all other species combined, mainly rattails (Macrouridae) and dogfishes (Squalidae), was low (13–120 t). Bycatch of this group dropped sharply in each year as the result of a combination of decreasing bycatch ratio and decreasing fishing effort.

Trawling damage to Northeast Atlantic ancient coral reefs.

This contribution documents widespread trawling damage to cold-water coral reefs at 840-1300 m depth along the West Ireland continental shelf break and at 200 m off West Norway. These reefs are spectacular but poorly known. By-catches from commercial trawls for deep-water fish off West Ireland included large pieces (up to 1 m(2)) of coral that had been broken from reefs and a diverse array of coral-associated benthos. Five azooxanthellate scleractinarian corals were identified in these by-catches, viz. Desmophyllum cristagalli, Enallopsammia rostrata, Lophelia pertusa, Madrepora oculata and Solenosmilia variabilis. Dating of carbonate skeletons using (14)C accelerator mass spectrometry showed that the trawled coral matrix was at least 4550 years old. Surveys by remotely operated vehicles in Norway showed extensive fishing damage to L. pertusa reefs. The urgent need for deep-water coral conservation measures is discussed in a Northeast Atlantic context.

The distribution of the scleractinian coralLophelia pertusaaround the Faroe islands and the relation to internal tidal mixing

Abstract A list of 138 positions with records of Lophelia pertusa is compiled from all published and unpublished investigations in the area including material from the BIOFAR research programme. In addition, Solenosmilia variabilis, another species of branching coral new to the area is reported. The Lophelia records are from areas that are dominated by the northeastern Atlantic water (NEA W) and in depths from 200 to c. 1000 m. The highest abundance of Lophelia tends to be in the depth range where the bottom slope is critical to internal waves of semidiurnal frequency. The causal link behind this is suggested to be an increase of food availability either through higher primary production at the surface or by a redistribution of suspended particles in the bottom mixed layer.