ALBERT

Description: Length-frequency data on squid (Loligo forbesi) collected during trawling surveys in Scottish waters from 1980 to 1994 were analysed to describe temporal and spatial patterns in abundance and to examine the prospects for using survey abundance to forecast fishery abundance. Loligo was patchily distributed in space and time. Distribution patterns in the North Sea in February appeared to be strongly related to bottom temperature (squid avoided waters 〈7°C) and, to a lesser extent, salinity (more squid in more saline water). For other areas and times, no temperature or salinity data were available, but there were trends for squid on the west coast to be more abundant in westerly areas and higher latitudes, and for squid at Rockall to be more abundant in shallow water. Inter-annual trends in abundance differed between the North Sea, west coast and Rockall, but average survey abundances for the North Sea and west coast tended to be positively correlated. For the North Sea and west coast, survey abundance was positively correlated with fishery abundance for the same month and area, and average abundance for the February North Sea survey was a reasonable predictor of commercial CPUE in the autumn of the same year (the peak of the fishery). Some of the observed trends were consistent with the existence of a stock-recruitment relationship but may indicate that abundance in a given calendar year is linked to climatic factors.

Description: An investigation was carried out on the recently discovered ‘giant’ extra large (XL) form of the squid Sthenoteuthis oualaniensis from the Arabian Sea. The sample consisted of 2 males, which have not been previously described, and 13 females. Diet composition, parasite loading, sucker ring dentition, biolumi-nescence and sexual dimorphism were examined and compared to known parameters of the medium (M) form. Reproductive strategy, potential fecundity, egg size distribution in the ovary and oviducts were examined in mature XL females. Evidence of multiple spawning in the giant form was also investigated. Overall body shape, bioluminescent structures and coloration of the giant form were similar to the M form, though the XL form had a smaller fin angle than the M form. The mature female XL form has a dorsal mantle length about twice that of a mature female M form. Adult females of the XL form have a dorsal mantle length about twice that of adult males of the same form. Differences between males and females were found in arm sucker ring dentition and parasite load, suggesting a difference in diet. This could be linked to size differences between the sexes. A strong correlation between ovary mass and mantle length was found (r2 = 0.64). Poor correlation was found between mantle length and oviduct mass (r2 = 0.128) and potential fecundity (r2 = 0.07). Potential fecundity ranged between 2–5 million eggs and the holding capacity of the oviducts was approximately 300, 000 eggs. This combined with the presence of spermatangia and the presence of food in the stomach suggest that the XL form is a multiple spawner. S. oualaniensis appears to have a plastic phenotype and has adapted to the Arabian Sea conditions by evolving the capacity to grow to a giant size.

Description: Stomach contents of a resident community of bottlenose dolphins (Tursiops truncatus) from the Sarasota Bay area of the westcentral coast of Florida were studied to examine potential factors leading to patterns of habitat use. Composition and size of prey were analyzed and correlated with feeding behavior of individual dolphins of known histories. Examination of stomach contents of 16 stranded dolphins revealed a diet composed exclusively of fish (15 species), most of which were associated with seagrasses in varying degrees. Observational records for 21 years showed that feeding typically occurred in shallow (2–3 m) waters and in the vicinity of seagrasses in 23% of cases. Dolphins usually fed alone or in small groups and on non-obligate schooling prey. The main species of prey were soniferous, an indication that passive listening may be important in detection of prey. The close agreement between species of fishes represented in stomach contents and habitat of prey, as indicated by observations of feeding, suggests that analysis of stomach contents is a reasonable approach for studying prey and feeding patterns of dolphins. Meadows of seagrass are one of the habitats of importance to dolphins in the Sarasota Bay area, and their protection is important for conservation of these animals.