ALBERT

Description: Intramantle pressure transducers allowed the monitoring of respiration and swimming performance of cannulated and freeswimming squid (IIlex illecebrosus). Jet pressure and oxygen consumption of individual squid were measured simultaneously in a tunnel respirometer at various swimming speeds. The rate of oxygen consumption increased logarithmically with swimming speed up to critical speeds of 70-90 cm/sec (about two body lengths per second). Oxygen consumption values for a400 g squid at 15° C were the highest that have been recorded for marine poikilotherms at this size and temperature: 313 ml/kg/hr for standard metabolism and 1,047 ml/kg/hr for active metabolism at maximum speed. A 40-cm squid (total length) uses about six times more energy per unit distance than a sockeye salmon of similar length at 15° C. The rate of oxygen consumption increased linearly with average jet pressure generated in the mantle cavity and the relationship was highly correlated for speeds of 0.15 0.80cm/sec. The results from telemetric monitoring of jet pressure generated by a free-swimming squid in a 15-m pool and the oxygen-pressure relationship show great promise for studying the activity and bioenergetics of squid in nature.

Description: Visual observations and video-tape records of the spawning of captive IIlex illecebrosus show that this species can produce gelatinous egg masses 50 cm or larger in diameter while swimming in open water. Measurements of the density of the eggs and the changes in water density which are necessary to lift egg masses indicate that the masses have densities about 0.005% greater than the water used to make the gel, whereas the eggs are more than 5% denser than typical seawater. The gel thus appears to function as a buoyancy mechanism which prevents eggs from sinking. Measurements of rates of temperature equilibration between egg masses and the surrounding water indicate that complete density equilibration requires many days under most conditions. If spawning occurs pelagically, common oceanographic situations where density increases with depth, due either to decreasing temperature (e.g. North Atlantic Central Water) or increasing salinity (e.g. the Gulf Stream), could allow the egg masses to be suspended in the mesopelagic zone. Such a mechanism, which could retain pelagically-spawned eggs of IIlex and other oegopsids, particularly ommastrephids, in a zone where temperatures are adequate to allow embryonic development, helps to explain why there are so few records of ommastrephid eggs in nature.

Description: The features of short-lived fishes and invertebrates relevant to their population dynamics and exploitation are reviewed, with emphasis on methodological approaches, which could lead to improved management of squid stocks. Several models are presented which offer the possibility of reducing what presently appear to be qualitative differences in the population dynamics of fishes and squids to quantitative differences, and, hence, to render squids amenable to the kind of comparative studies which, for fish, have rendered preliminary stock assessments possible even when data are scarce.

Description: Various aspects of maturation in male IIlex illecebrosus were examined in an attempt to find evidence for a more realistic maturity scale than that currently in use. Simple indices, based on morphology of the hectocotylized arm, failed to provide satisfactory relationships, but the observed variation in hectocotylus measurements may provide useful insights into the population ecology of the species. The earlier maturation of males than females and the observed premature release of spermatophores cast doubt on the usefulness of spermatophore counts as the basis for developing a reliable maturity scale for male I. illecebrosus. Preliminary examination of spermatophores and spermatozoa with lighl and scanning electron microscopes have so far failed to reveal any difference between material from early and late "mature" males.

Description: Catches of rhynchoteuthion type C' larvae, which are considered to be II/ex illecebrosus, and I. il/ecebrosus juveniles over the edge of the continental shelf between Cape Hatteras and Florida are examined in relation to the water masses and their dynamics along the Gulf Stream~Slope Water frontal zone. All larvae and juveniles were captured at stations where the temperature~salinity (T-S) properties of the upper 50 m of the water column were closely grouped, with temperatures of 21.0° to 23.5° C and salinities of 36.30 to 36.80, which are very similar to those of Continental Edge Water. Although the actual depths of capture of the larvae and juveniles in the bongo and midwater trawl tows are unknown, it is likely that the majority were taken in the upper 50 m. Larvae and juveniles were intermixed along the entire frontal zone, but there are indications of some differences in microscale distribution. Although juveniles were nearly always captured at stations where larvae were taken, larvae were captured at only 44% of the stations where juveniles were found. The intermixture of larvae and juveniles with a broad range of size (mantle length) indicates that spawning occurs either along the Gulf Stream~Slope Water frontal zone south of Cape Hatteras or in a relatively small area to the south of the surveyed area. The possible role of frontal eddies in causing the intermixture of larvae and juveniles is discussed.

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.

Description: The Illex larvae inhabit the epipelagial of the shelf waters, the continental slope and the Gulf Stream where the temperature and salinity range from 11.2 to 20.10°C and from 34.50 to 36.56%, respectively. The largest recorded aggregations were in the continental slope area of the Mid Atlantic Bight (MAB) between 35° and 38°N, and in the northern periphery of the Gulf Stream to 65°w. Illex illecebrosus spawn in the pelagial of the continentalslope between. the Florida Peninsula and 40°N. The spawning periodextends from September to May, with December-February as peak spawning months. Egg masses found in the spawning ground have a positive bouyancy.

Description: A technique has been developed which improves the accuracy andefficiency of ageing squid over previously described methods. The spatial pattern of growth increments is studied using light andscanning electron microscopy techniques. Daily growth increments in statoliths are validated by employing chemical 'time' markers e.g. strontium and tetracycline, and known-agelaboratory-reared animals. Increment formation is suggested to beintrinsically controlled. Increments begin to form immediately after hatching.

Description: Preliminary estimates were made of quarterly and annual quarterly and annual consumption by Illex and Lollygo in Subareas 5 and 6, for 1979 and 1980. Euphausiids made up a considerable proportion of the diet of both species in the spring offshore. Overall, predation onfish was greater by Loligo and cannibalism was greater by Illex. Consumption estimates varied with feeding intensity and biomass.

Description: A new method of counting growth increments in the statoliths of IIlex illecebrosus is described. The increments were found to increase in number with length of statolith and dorsal mantle length of the squid. However, statolith length was found to vary less than number of increments in individual samples and may prove to be a better indicator of age. The increment-bearing portion of the statolith can be divided into three regions on the basis of increment widths and their variation. These regions reflect different stages of development of the animal. Larval retention of gross morphological characteristics, and changes in growth pattern and configuration of the statolith indicate that the larval condition extends beyond the rhynchoteuthion stage (about 8 mm dorsal mantle length) and may include squid up to 50 mm.

Description: A modified version of yield-per-recruit analysis wasused to estimate potential yields in the Loligo pealei fishery off the northe stern USA. The mode1 accepts monthly values of growth and fishing, spawning and natural mortality rates and assumes two cohorts per year class, as associated with pawning peaks. Two patterns of exploitation were examined by simulatting dominance of the international fishery (offshore, winter fishing coupled with the domestic inshore summer fishing) and the domestic fishery alone through varistion of the monthly pattern of fishing mortalita. Parameter estimates were derived from survey catch per tow and commercial catch data.

Description: The six species of commercially important squid in the Southeastern Fisheries Region, (Loligo pealei, Dorytheuthis plei, Lolliguncula brevis, Illex illecebrosus, I. coindeti and I. oxygonius) show separate seasonal distribution patterns and depth and temperature preferences. With the exception of Lolliguncula brevis, major concentrations are associated with topographic features which cause upwellings, such as the Charleston Bump, and resulting nutrient rich waters or nutrient laden waters around the delta of the Mississippi River. Anecdotal information from surveys and commercial fishermen support the presence of considerable stocks of squid in the Gulf of Mexico and along the Atlantic coasts of Florida and the Carolinas.

Description: Pressure transducers, measuring intra-mantle pressure allowed monitoring of total P-V work associated with swimming and respiration in cannulated and free-swimming squid (Illex illecebrosus).

Description: Visual observations and video-tape records were made for the first time of mid-water spawning by Illex illecebrosus in the Aquatron Laboratory pool tank. Coupled with data on the density of egg masses, they allow some conclusions to be drawn concerning possible mid-water spawning sites in nature.

Description: Development stages for artificially fertilized and naturally spawned eggs of Illex illecebrosus were observed and a staging scheme proposed which relates to earlier studies on naturally spawned eggs of Illex coindetii and artificially fertilized eggs of Todarodes pacificus. Photographs and descriptions of stages provide a reference for embryonic development of small ommastrephid eggs and an aid to the identification of egg masses of the species in nature, an essential step in understanding its life cycle. Embryonic development in Illex illecebrosus fails at temperatures below 12.5°C. and the development rate at 21°C is nearly twice that at 12.5°C. This temperature requirement restricts the spatial and temporal distribution of spawning in this squid, and temperature-related development rates allow prediction of the age of egg masses found in nature in water masses of a particular temperature.