Feeding Habits of Fish Species Distributed on the Grand Bank (NAFO Divisions 3NO, 2002-2005)

24197 stomach contents corresponding to 17 fish species of the Grand Bank in the period 2002-2005 were analyzed. Importance of prey was based in weight percentage. Feeding intensity was high for most species (>75%). Greenland halibut and northern wolffish were the species with the lowest feeding intensity (70% of the total weight. Greenland halibut, Arctic and spynitail skates were piscivorous species. Roundnose grenadier, redfish and smooth skate showed pelagic, bathypelagic or epifaunal crustacean feeding habits, and northern wolffish was pelagic invertebrate organism feeder on ctenophores. Roughhead grenadier and yellowtail flounder were benthic predators on different prey species, scyphozoans and crustaceans respectively, and polychaetes were common in the diet of both species. Witch flounder and round skate were polychaete feeders on bottom benthos. Atlantic and spotted wolffish showed a diet primarily based on benthic and bottom organisms with predominance of different prey in each species. Black dogfish preyed on benthic groups (crustaceans, scyphozoans and fishes), like American plaice (echinoderms, fishes and crustaceans). Thorny skate and Atlantic cod showed similar diets based on fishes and crustaceans. Specific predation and diet overlap observed among some species changed with depth

Evaluating the use of the autodiametric method for estimating fecundity of Reinhardtius hippoglossoides, a species with an unusual oocyte development strategy

The autodiametric method is a highly streamlined method for estimating fecundity of fish with determinate oocyte development pattern. Greenland halibut presents a peculiar reproductive strategy with two simultaneously cohorts one of large vitellogenic oocytes (for the current year) and another one of small vitellogenic oocytes (for the subsequent year). Results of this study showed that autodiametric method can be applied to estimate fecundity in Greenland halibut. Additionally, spatial differences in the autodiametric calibration curve were observed in the Northwest Atlantic, but did not translate into differences in fecundity at length. This is the first time that spatial differences between ACCs of the same species have been reported, what could be the result of (i) the unusual oocyte development pattern, or (ii) spatial differences in oocyte biochemistry. More research on the relative dynamics of oocyte cohorts simultaneously present in Greenland halibut ovaries and the factors (endo- or exogenous) influencing oocyte packing density could provide a better understanding of observed geographical differences.En prens

A review of NAFO 3LMN roughhead grenadier (Macrourus berglax Lacepède, 1801) reproductive biology including the evaluation of maturity ogive estimates.

A collection of 4770 histological slides collected in NAFO divisions 3LMN in a depth range from 200 to 1500 m and covering a time period between 2001 and 2015, has been reviewed to obtain information on reproductive biology of Macrourus berglax. Especial attention has been paid in atresia because its potential impact on stock productivity. Spatial and temporal variability of size and age at maturity of female roughhead grenadier was analyzed in NAFO divisions 3LMN based on microscopic maturity staging and individual age readings. Spawning capable females are homogeneously distributed nearly year-round, but in scarce numbers what prevent to define a spawning season. This statement united to the high levels of atresia could indicate a reproductive migration. We observed a clear decrease in length at first maturity (L50) of females from 27.8 cm in the period 2005-2011 to 25.6 cm in the last four years. The age at first maturity, A50, varied between 13.1 and 15 years, and there is not an evident trend of change over the years.Postprint0,000