Hippoglossoides Platessoides Fabricius Research Articles

Condition and feeding of American Plaice (Hippoglossoides platessoides) in the North Atlantic with emphasis on the Flemish Cap

The seasonal, annual and geographical changes in the Relative Condition Factor (Kr) of a total of 24 410 individual American plaice (Hippoglossoides platessoides Fabricius) were analysed. These samples were collected in three areas of the North Atlantic (NAFO Division 3M and Div. 3LNO, and ICES Div. IIb) in commercial fishing and scientific surveys from 1992 to 2003. Condition presented significant variation in both sexes as far as area, season and year effects were concerned. Condition decreased greatly in Div. 3M, slightly increased in Div. IIb and it was quite constant in Div. 3LNO in the considered period for each area. Relative Condition Factor value showed a remarkable relation with the estimated biomass in Div. 3M. Females showed a better condition than males, and condition in the periods of spring and summer was lower than in the periods of autumn and winter for both sexes. Interannual variation in condition was more evident in small sized (immature) individuals. The spawning period corresponded with the peak of condition in females and with a decrease in males. Feeding intensity and condition were inversely related across season, however when the same period was studied across years they showed a similar pattern. Food and feeding of 8 543 individual American plaice from these three areas were examined. Feeding intensity was higher on the Flemish Cap (78%). The main prey in the composition of stomach contents for this area, were Ophiuroidea (56%), Hyperiidea (13%) and Pandalus borealis (8%). Changes in the main components of the diet were found in the last years. Feeding habits by size range and comparison with the other areas were also analysed.

Food partitioning by flatfishes on a herring spawning ground

Inter- and intraspecific dietary variations and diet overlap patterns of plaice ( Pleuronectes platessa L.), dab ( Limanda limanda L.), lemon sole ( Microstomus kitt Walbaum) and long rough dab ( Hippoglossoides platessoides Fabricius) from a coastal bank off Norway were analysed. Sandeel ( Ammodytes marinus Raitt) was the dominant prey in terms of weight of both plaice and dab, while polychaetes were the most common prey of lemon sole. The long rough dab, which tended to occur in deeper waters than the other species, fed mainly on crustaceans and echinoderms. In March-April, when the Norwegian spring-spawning herring stock uses the bank as spawning ground, herring eggs were consumed by lemon sole and to a lesser extent the plaice and dab. There were indications of partitioning of food resources among the co-occurring species, but also extensive diet overlap when feeding on sandeel and herring eggs that were probably very abundant.

The population structure of the brittle star Ophiura sarsi Lütken in the Gulf of Maine and its trophic relationship to American plaice ( Hippoglossoides platessoides Fabricius)

This study examines the population structure of the ophiuroid Ophiura sarsi Lütken in an area southeast of Portland, Maine and its exploitation by its major predator, the flatfish, American plaice ( Hippoglossoides platessoides Fabricius). Ophiura sarsi and American plaice were sampled during a 1-yr period (1985–1986) from a site of 148–156 m depth. The bimodal size-frequency distributions of the O. sarsi population were dominated by small individuals with disk diameters between 2 and 11 mm, and with estimated growth rates, based upon the modal progressions from the persistent 1985 year class, of ≈4 mm per year. Larger individuals (≈15–25 mm) were generally less numerous. These older brittle stars, which formed the right-hand peaks of the size-frequency distributions, displayed little noticeable growth, which suggests that these peaks were comprised of multiple cohorts. Recruitment to the population appeared to be continuous, due to the occurrence of 1 mm or smaller brittle stars throughout most of the year. The strong presence of 1 mm or smaller O. sarsi in January, 1986 indicated a major recruitment event. A survey of the reproductive condition of the gonads showed evidence of continuous but seasonally variable reproduction, with the major spawning centered around January. O. sarsi was the major dietary constituent of the American plaice, occurring in at least 65% of the fish stomachs throughout the year. Plaice consumed the most abundant size classes of O. sarsi in the population, with disk sizes between ≈4 and 10 mm. These brittle stars were of low caloric value, yet the more nutritious, older brittle stars were not eaten in significant numbers by even the largest plaice. The high proportion of small, energy-poor O. sarsi found in the plaices' diet might be the result of their greater abundance or accessibility at this site.

Age and Growth of American Plaice (Hippoglossoides platessoides) in the Newfoundland Area of the Northwest Atlantic

Growth curves of American plaice (Hippoglossoides platessoides Fabricius) from the Grand and St. Pierre banks and the areas east of Newfoundland are presented. Ages were determined using otoliths from random samples collected by research vessels in the spring and summer during 1957–63.For the localities sampled, American plaice on the southern half of the Grand Bank are the largest and the St. Mary's Bay population the smallest at comparable ages. A positive association was found between the sizes at ages 5 and 15 for the various localities and the probable bottom temperatures.Samples of otoliths from St. Mary's Bay indicated that the greatest growth occurs during the May–November period.Year-class dominance was noted for St. Mary's Bay, but not for other areas.