Hyperiid amphipods distribution between the central coast and oceanic islands off Chile, southeastern Pacific

The composition, distribution, and abundance of hyperiid amphipods collected in the oceanographic cruise between the central coast and oceanic islands of Chile in the southeastern Pacific were analyzed. Thirty-four genera and 54 species were identified, grouped into two infraorders and 16 families. The presence of Hemityphis tenuimanus Claus 1879, and Laxohyperia vespuliformis Vinogradov & Volkov 1982, expands its geographical distribution as new records for the southeastern Pacific. According to the founded species, spatial distribution, and the bodies of water present in the study area, Chile’s central region would be a transition zone for species originating from the Magellan Province (Subantarctic water) and the Peru-Chile Province (Subtropical water).

Influence of Subantartic and Subtropical Oceanic Water on the Zooplankton and Hydrology of Waters Adjacent to the Derwent River Estuary, South-eastern Tasmania

The oceanic influence on coastal waters adjacent to the mouth of the Derwent River estuary was examined over a season using zooplankton samples. There is strong evidence to indicate the influence of oceanic water in Storm Bay and the mouth of the Derwent River estuary. The occurrence of indicator species suggests that the area is invaded by subantarctic water from August to January and by subtropical water most strongly in February and March. The seasonal abundance and distribu- tion of the major copepods (12 species), chaetognaths (three species), one euphausiid and one tunicate species are described in detail and the importance of these species as indicators of intrusion and mixing of water masses in this region is evaluated.

Calanus tonsus (Copepoda, Calanoida) in southern New Zealand waters with notes on the male

Calanus tonsus, a subantarctic planktonic copepod, was taken abundantly in surface waters off south-eastern New Zealand in spring and early summer (September to January). Nearly two generations are passed in this time but individuals of the second generation appear to descend into deep water as Stage V copepodites. Here they overwinter before they mature and breed in August. Males were not taken at all in surface samples and only appeared in deep water upon the maturation of the overwintering stocks. When they first appear, males outnumber females. C. tonsus was seasonally abundant near the surface in the Southland Current, and further offshore in subantarctic water, but not in neritic waters near the shore. It is probably introduced into the Southland Current each spring from deeper subantarctic water. C. tonsus is closely related to C.plumchrus of the North Pacific and the two species have many similarities in their life-cycles and hydrological afiities. The male of C. tonsus has been more fully described in this paper.