As part of the Georges Bank/North West Atlantic GLOBEC (Global Ocean Ecosystems Dynamics) Program, macrozooplankton and micronekton were collected on 30Broad Scale Survey Cruises between January -June, 1995-1999

Quantification of the movements and home ranges of highly mobile marine species is a challenging prerequisite for a more complete understanding of their ecology. Caranx crysos is a pelagic carangid found in large schools over the mid-shelf of the northern Gulf of Mexico. Twentythree C. crysos were surgically implanted with acoustic transmitters, and their positions were localized around a petroleum platform complex in the Gulf of Mexico using a hydrophone network. Fish were tracked during August 2005 for 23 d, and home ranges were calculated for individual fish over the daily, diel, and entire study period. Most fish showed a preference for a discrete area within the platform complex: 11 fish had a range centroid near one platform for at least 7 d, and 9 fish had a range centroid near one platform for at least 3 d. Only 3 fish showed no preference for a particular site within the platform complex. Mean core daily range varied from 373 to 2202 m 2 , while the 95% daily range was between 3082 and 14 333 m 2 . Evidence for diel differences in habitat use was also apparent. Hydrophones detected more transmissions during the day than during the night; however, only 3 fish had significantly larger home ranges during the day than during the night. There was a significant correlation between fish length and both the size of their overall core home range and the size of the 95% daily home range. Our results suggest that this schooling pelagic species establishes a home range in the vicinity of structure.

We have used a stochastic population model to simulate the prawn size distribution in the grow‐out ponds as a function of time. The model allows for growth and mortality parameters which are dependent on size class and pond biomass. We have written a computer program based on this model in which the user inputs a stocking number, a stocking size distribution, a stocking schedule, the harvest size classes, and a harvest schedule. The computer then computes the number of prawns and the prawn size distribution in the pond at specified time increments and a quarterly production economics summary. We compare simulated growth and harvest data generated by the program to actual growth and harvest data from Hawaii and Florida. We also use the program to evaluate the effects of stocking number, stocking schedule and stocking size on annual yields from a prawn grow‐out pond.

We sampled for vertical distribution and possible diel vertical migration (DVM) of Crangon septemspinosa Say, 1818 on and around Georges Bank, Northwest Atlantic, between 1995 and 1999. Both juveniles and adults were found to undergo DVM, being distributed within the lower water column (and perhaps on or in the bottom) during the day, and distributed throughout the water column at night, with higher abundances seen in all depth strata at night. Differences in vertical distribution were also found based on location and chlorophyll concentration for juveniles, but no effects were seen of season, salinity, temperature, lunar periodicity, year, or copepod prey for either juveniles or adults. Variation in vertical distribution and DVM were only moderately well explained (50% of the total variance) by the above factors, suggesting that some other factor(s) not measured by us (e.g., predation) were potentially also controlling the vertical distribution and diel migration of C. septemspinosa on Georges Bank. RÉSUMÉ Nous avons échantillonné Crangon septemspinosa Say, 1818 sur et autour de Georges Bank, Atlantique nord-ouest, entre 1995 et 1999 pour sa distribution verticale et ses possibles migrations verticales journalières (DVM). Juvéniles et adultes ont présenté des DVM, étant distribués dans la colonne d'eau basse (et peut être sur ou dans le fond) durant la journée, et distribués à travers toute la colonne la nuit, avec de plus fortes abondances trouvées dans toutes les strates verticales pendant la nuit. Chez les juvéniles des différences de distribution verticale ont aussi été trouvées en relation avec la localisation et la concentration en chlorophylle, mais aucun effet n'a été trouvé pour la saison, la salinité, la température, le cycle lunaire ou les proies de copépodes aussi bien pour les juvéniles que pour les adultes. Les variations de distribution verticale et de DVM ont été seulement modérément expliquées (50% de la variance totale) par les facteurs précités, suggérant que d'autre(s) facteur(s) non mesurés (e.g., prédation) pourraient aussi contrôler la distribution verticale et la migration diurne de C.