ALBERT

Description: The inadequacies of population data in the determination of squid life history models is discussed. A close, functional comparison is noted for myopsids (Loligo pealei in particular) and the sepiolid squids. Though the latter are small andstrictly nekto-benthic, they are capable of laboratory cultivation and provide excellent models for experimentation. It is now possible to test the physiologicalchanges which support the seasonality of Mesnil's model and to examine the roleof elective spawnin (as proposed here) and social interactions. A qualitative myopsid-sepiolid life cycle summary is presented to illustrate present ecological knowledge on this subject. The subject is briefly discussed in terms of squid fishery management in general.

Description: The general relationship between the ecology of cephalopods and their environments is briefly reviewed from available information on the fisheries, biology and physical environments of various species which constitute the major cephalopods resources of the world's oceans. The relationship is further examined by reviewing the features of two large-scale oceanographic systems and a relatively small-scale system. The large-scale systems are the Kuroshio Current in the Northwest Pacific relative to the ecology of Todarodes pacificus and the Gulf Stream in the Northwest Atlantic relative to the ecology of IIlex illecebrosus. Similar biological characteristics of both ommastrephid squids are found in relation to the dynamics of both ocean currents. However, differences in the oceanographic regimes of both regions seem to account for the differences that are known to exist in the structure of the squid populations in the regions. The small-scale system is the California Current in the Northeast Pacific relative to the ecology of Loligo opalescens, for which association between life-history features and the physical oceanographic regime can also be identified. Comparison of the Kuroshio Current and the Gulf Stream systems are considered to be important in clarifying incomplete aspects of the life cycle of I. illecebrosus in the Northwest Atlantic.

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.

Description: Feeding studies of short-finned (Illex illecebrosus) andlong-finned (Loligo pealei) squids were conducted during the May to November period of 1976 on the Nova Scotian shelf, on Georges Bank and in adjacent waters. The analysis of 2 604 sp. Of Illex and 578 sp. of Loligo, showed that the food composition of both species was predominated by fish and squids. Cannibalism was more typical of short-finned squids and the fish were a prevalent food items in the long-finned squids' diet. In all areas and at all depths, coefficients of stomach fullness for larger short-finned squids were 1.5-2 times higher than for smaller specimens, although the feeding intensity of both groups was low. The feeding intensity of immature long-finned squids was higher than that of mature specimens.

Description: In years of high abundance, the short-finned squid (Illex illecebrosus) was a common prey of Atlantic cod (Gadus morhua) in summer and autumn in both inshore and offshore waters of eastern Newfoundland and in the eastern and northern Gulf of St. Lawrence.The frequency of occurrence of squid in cod stomachs and the number of squid per stomach increased with cod length. The intensity of predation by cod on squid was low compared with peak predation on capelin (Mallotus villosus) and sand lance (Ammodytes sp.). Nevertheless, the annual immigration of squid in years of high abundance provided an increase in total food availability, especially for large cod.

Description: The life cycle of the short fin squids of the North-west Atlantic, ranging in the area from the Florida Peninsula to Labrador as a single population (Romero and Amaratunga, 1981; Froerman, 1983; Froerman, Dubinina, 1984), was studied. The data on the distribution and biological parameters of the population in different ontogenetic stages was collected du-ring the 1966 to 1983 period. Information on the distribution and biology of the short fin squids inhabiting the areas south of Cape Hatteras and north of Banquerreau Bank was mainly adopted from the literary sources.

Description: Oogenesis and the development of the reproductive organs in Illex illecebrosus females was studied. The sample analyses were obtained from the area between Cape Hatteras and the Grand Bank in 1966-1983. To investigate the oogenesis, 10 gonads were taken from the females with the mantle length of 15-30 cm at allmaturity stages (except spawning). Approximately 2,000 specimens were studied to obtain knowledge of thedevelopment of the reproductive system organs during the ontogenesis. More than 50,000 females were sampled to analyse the maturation dynamics and the distribution during their life cycle. Data on the spawning andspent females were obtained for Illex argentinus.