Distribution and biomass of two squid species off southern New Zealand: Nototodarus sloanii and Moroteuthis ingens

The distribution and biomass of two species of squid, the ommastrephid arro w squid Nototodarus sloanii and the onychoteuthid squid Moroteuthis ingens, were analysed off southern New Zealand. These two species are the most imp ortant and abundant species in this region of the South Pacific Ocean. Data were obtained from extensive NIWA research cruises over 10 years. There wa s a sharp demarcation between the distribution of the two species, with N. sloanii occurring predominantly shallower than 600 m, with the greatest bio mass less than 300 m. In contrast, M. ingens had the highest biomass betwee n 650 and 700 m and occurred down to 1400 m. The biomass of N. sloanii reac hed more than 3500 kg.km(-2) with an average catch rate of over 186 kg.km(- 2) In contrast, the biomass of M. ingens was more than an order of magnitud e less, with all catch weights less than 200 kg.km(-2) and an average catch rate less than 17 kg.km(-2). The separation of these two species appeared to be related to depth, temperature and, possibly, salinity. N. sloanii occ urred predominantly in warmer, shallower subtropical waters while M. ingens occurred in deeper, cooler subantarctic and antarctic intermediate water m asses. The Subtropical Front formed a major barrier between the distributio n of these two squid species.