Zealand Hoki Research Articles

Genetically isolated stocks of orange roughy (Hoplostethus atlanticus), but not of hoki (Macruronus novaezelandiae), in the Tasman Sea and Southwest Pacific Ocean around New Zealand

Restriction fragment-length polymorphisms of mitochondrial (mt) DNA, generated by six-base restriction enzymes, were used to examine the stock structure of the two major commercial species in New Zealand fisheries, orange roughy (Hoplostethus atlanticus Collett) and hoki (Macruronus novaezelandiae Hector). Samples of orange roughy from six spawning sites around New Zealand and one site off Tasmania show significant genetic heterogeneity. Samples from two sites around the south of New Zealand were genetically similar to each other, but dissimilar to samples from all other sites. The common haplotype observed in northern sites was absent from the two southern sites. Low numbers of unique haplotypes were restricted to the Challenger Plateau in the Tasman Sea. There was no significant genetic heterogeneity in five samples of hoki from two spawning sites off New Zealand and one site off Tasmania.

Analysis of spatial structure in fish distribution using commercial catch and effort data from the New Zealand hoki fishery

A linear model was fitted to commercial catch per unit effort data in the spawning hoki trawl fishery off the west coast of the South Island of New Zealand. Correlations in the residuals from this model extend out to 11 nautical miles and persist for periods of up to 14 days, suggesting that there is patchiness in the fish distribution on this spatial and temporal scale. Simulation studies show that this method can detect patchiness in the density distribution even when the trawl shots are comparable in length with the size of the patches, and that the extent of the correlations correctly estimates the size of the patches. Resume : Un modle linOaire a OtO adaptO aux donnOes de prises commerciales par unitO dieffort liOes ‡ la pŒche au chalut de hokis reproducteurs sur la cUte ouest de liOle sud, Nouvelle-ZOlande. Les corrOlations dans les rOsidus de ce modle siobservent sur une distance de 11 milles marins et durant une pOriode pouvant atteindre 14 jours, ce qui porte ‡ croire que la distribution des poissons sur cette Ochelle spatio-temporelle est irrOgulire. Des Otudes de simulation rOvlent que cette mOthode permet de dOtecter liirrOgularitO de la distribution de la densitO mŒme lorsque la longueur des traits de chalut correspond ‡ celle des taches et que liOtendue des corrOlations permet diestimer correctement la taille des taches. (Traduit par la ROdaction)

Analysis of vessel movements and strategies using commercial catch and effort data from the New Zealand hoki fishery

On a examine des valeurs normalisees de taux de capture obtenues au moyen d'un modele multiplicatif des prises de peche commerciale par unite d'effort dans le cadre de l'etude des deplacements et des strategies d'un bateau de peche. On a fait une transformation logarithmique des prises par unite d'effort effectuees dans une peche commerciale au chalut du hoki en fraye, au large de la cote occidentale de l'ile South, en Nouvelle-Zelande; on a ensuite ajuste un modele lineaire aux donnees transformees. Les valeurs residuelles obtenues au moyen de ce modele ont ensuite ete examinees; les taux de capture resultant de traits de chalut effectues par differents bateaux a differents moments de la journee ont ete normalises, si bien qu'ils sont comparables. Les decisions relatives au lieu de peche seraient fondees tant sur les antecedents de capture recents du bateau que sur les observations relatives au lieu de peche et au regroupement des autres bateaux. Rien n'indique que le transfert d'information soit suffisant pour que les decisions soient fondees sur le taux de capture des autres bateaux de la flottille.

Analysis of spatial structure in fish distribution using commercial catch and effort data from the New Zealand hoki fishery

Analysis of spatial structure in fish distribution using commercial catch and effort data from the New Zealand hoki fishery

Characterization of New Zealand Hoki and Southern Blue Whiting Surimi Compared to Alaska Pollock Surimi

Representative commercial lots of surimi produced from the New Zealand fish species hoki (Macruronus novaezelandiae) and Southern blue whiting (Micromesistius australis) were compared to that of Alaska pollock (Theragra chalcogramma) on the basis of functional properties and composition. Parameters studied included gelling response to preincubation and cooking for various times and to the addition of water and starch as well as frozen stability at -8°C. There were few species-related differences in response to the various treatments, although differences in absolute values of rheological parameters were noted. Surimi from the three species should be interchangeable with few or no modifications needed in the operating procedures of food manufacturers.