Publication Date:
2020-06-19
Description:
Two species of arrow squid (Nototodarus sp.) were sampled with bottom trawl during nine research surveys along the north and east coast of South Island, New Zealand, from January 1982 to March 1983. There was minimal overlap between the two species. Species 1 was associated with subtropical water along the north coast (Tasman Bay) of South Island and Species 2 with the Subtropical Convergence Zone and subantarctic water along the east coast. Catches of Species 2 varied markedly with geographic location, depth (from 50 to 500 m) and sampling period, but were consistently lowest in January of both years. Differences in the size composition of Species 2 with depth were associated with differences in the relative abundance of juveniles. Juveniles of Species 2 were most abundant at 50 and 100 m and were rare or absent at 30 and 500 m. Size distributions of males and females of both species were generally similar for each depth and sampling period. Modal sizes (dorsal mantle length) of Species 1 indicated growth rates of 3.0-4.5 cm per month for three cohorts which were separated by about 6 months. Spawning of Species 1 probably occurs around November and April of each year, and maximal size (about 40 cm) is attained in about 1 year. Size distributions of Species 2, were polymodal and did not give clear indications of growth or spawning period. This may be due to a mixture of several subpopulations of Species 2 along the east coast of South Island, differing in age structure, spawning period and growth rate.
Type:
Article
,
PeerReviewed
Format:
text
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