Spatially integrated modelling of data-limited orange roughy (Hoplostethus atlanticus) using environmental covariates

Spatial stock assessment models are recognised as increasingly important for estimation of stock status and a sustainable exploitation rate. The inclusion of movement between spatial units within a model is difficult, because the data requirements are high. However for populations with low levels of spatial exchange it is possible to reduce the data requirements by distributing information on biological parameters between neighbouring units, or units with shared environmental conditions. This can allow spatial modelling to be applied even in data-limited situations. We develop this approach here through application to orange roughy (Hoplostethus atlanticus) sub-populations inhabiting neighbouring seamounts in the South Pacific. Despite limited data for each seamount, we were able to simultaneously fit multiple, localised, process-based models of the depletion dynamics. This was achieved by sharing information on the unexploited population size via known environmental covariates, with the relationship estimated in a hierarchical and integrated manner during the model fit. Cross-validation demonstrated that this approach can compensate for a lack of seamount-specific abundance data and improve ability of the model to estimate localised depletions.

Twenty-one new records of fish species (Teleostei) from the New Caledonian EEZ (south-western Pacific Ocean)

New records of fish species are reported from New Caledonia, includingPolyipnus aquavitusBaird, 1971 (Sternoptychidae),Porogadus melampeplus(Alcock, 1896) (Ophidiidae),Hoplichthys citrinusGilbert 1905 (Hoplichthyidae),Plectrogenium nanumGilbert 1905 (Plectrogeniidae),Lioscorpius trifasciatusLast, Yearsley & Motomura 2005 (Setarchidae),Neomerinthe megalepisFowler 1938 andPhenacoscorpius megalopsFowler 1938 (Scorpaenidae),Ocosia apiaPoss & Eschmeyer, 1975 (Tetrarogidae),Hoplostethus atlanticusCollett 1889 (Trachichthyidae),Zenion longipinnisKotthaus, 1970 (Zeniontidae),Plectranthias forestiFourmanoir 1977,Plectranthias pelicieriRandall & Shimizu, 1994,Plectranthias rubrifasciatusFourmanoir & Randall, 1979 andRabaulichthys squireiRandall & Walsh, 2010 (Serranidae),Synagrops philippinensis(Günther 1880) (Acropomatidae),Stegastes insularisAllen & Emery 1995 (Pomacentridae),Cirrhilabrus rubrimarginatusRandall 1992 (Labridae),Pteropsaron neocaledonicus Fourmanoir & Rivaton, 1979 (Percophidae),Centrodraco ornatus(Fourmanoir & Rivaton, 1979) andDraconetta xenicaJordan & Fowler 1903 (Draconettidae), andAcanthurus maculiceps(Ahl 1923) (Acanthuridae). A record ofPlectropomus maculatus(Bloch 1790) (Serranidae) from Grande Terre, New Caledonia is confirmed. This paper also includes new depth records ofZenion longipinnis, Plectranthias rubrifasciatus, Synagrops philippinensis, Centrodraco ornatusandDraconetta xenica.

IDENTIFICATION OF VOLATILE FLAVOUR COMPOUNDS OF HOKI (Macruronus novaezelandiae) AND ORANGE ROUGHY (Hoplostethus atlanticus) OILS

Identification of volatile flavour compounds of hoki (Macruronus novaezelandiae) and orange roughy (Hoplostethus atlanticus) oils has been carried out. Flavour compounds were extracted by a purging system and collected using a porous polymer Tenax TA trap. The gas chromatography-mass spectrometry (GC-MS) was used to identify the volatile flavour compounds. The predominant compounds contributing to the volatile flavour of hoki oil were methyl ethyl benzoate, ethyl benzoate and 1,1-dimethylethyl-2-propionic acid. Meanwhile, the main volatile flavour components of orange roughy oil were toluene, cyclohexane, 1,1-dimethylethyl-2-methyl propionic acid and tetrachloroethane.