Atlantic mackerel Scomber scombrus had low clearance rates when fed older stage copepodites of the copepod Calanrls finmarchicus at high concentrations dnd high clearance rates at low concentrations These rates were consistent ivith filter feeding at high concentrations and particulate feeding at low concentrations. Intermediate and sinall copepods presented together at high concentrations were cleared at lower ]-ales than the large C finmarch~cus, suggesting lower filtration efficiencies Intermediate and small copepods were presented over a range of light intensities (8 2 X 10-' to 1 6 X 1 O0 pE m-' S-' ). Fccding rat,, did not change s~gnlficantly bet~veen 1.6 X 10" and 2 0 X 10." pE m-' S-', but decreased to nearly zero C I~ 8 2 X 10-"E 111 ' S , indicating a light intensity threshold for feeding of about 10 ' PE m-' S-'. This threshold enables mackt'rcl to itled throughout the night near the ocean surface. Swimming speed d e c r e a x d to a lesser degree than feeding rate at the lowest hght ~ntensity, indicating that the change in filter-feeding rate IS only part~ally due to the change in speed. The school dispersed In both low and high l~g h t levels, but spacing between f~s h did not appear to be related to feeding rate KEY WORDS: Mackerel Scomber scon~bi-us Calanus finmarch~cus Filter feeding Light intensity (irradiance) . Schooling behavior

Johnson, A. K., Richards, R. A., Cullen, D. W., and Sutherland, S. J. 2008. Growth, reproduction, and feeding of large monkfish, Lophius americanus. – ICES Journal of Marine Science, 65: 1306–1315. The American monkfish, Lophius americanus, supports important commercial fisheries in the Northwest Atlantic. Although life history information is available for smaller L. americanus, the biology of large monkfish (>70 cm) is poorly understood because relatively few large fish are caught in standard resource surveys. Between 2006 and 2008, 699 L. americanus of 71–118 cm total length were collected from commercial gillnet fishers operating in the mid-Atlantic Bight (n = 689) and in the Gulf of Maine (n = 10) to investigate growth rates, reproductive biology, and feeding habits of large monkfish. All those collected were mature females ranging in age from 7 to 13 years. Growth was linear at an average annual rate of 7.6 cm. Hepatosomatic indices peaked in February and gonadosomatic indices between February and April. Postovulatory follicles and vitellogenic oocytes were observed in the same ovaries, evidence that monkfish spawn over a protracted period and possibly more than once annually. Food habits were similar to those reported for smaller benthic phase monkfish, but cannibalism was more prevalent in large fish (5.6% frequency of occurrence). Frequencies of feeding and cannibalism were greatest in females in the final stage of oocyte maturation.

Parallel macrostructure analysis of otoliths versus scales was conducted on Georges Bank Haddock Melanogrammus aeglefinus sampled in spring 2011 to test whether annuli widths of both structures yield comparable estimates of back‐calculated length at age. While generally similar in number, scale and otolith annuli were found to differ systematically in their relative widths, mainly because initial annuli are deposited closer to the origin in scales than in otoliths. Accounting for the delayed onset of scale versus otolith formation did not remove the systematic bias. To make both structures comparable, we developed an age‐independent correction approach that can adjust cumulative relative annuli widths (RAWs) of Haddock scales to otolith RAWs by the quadratic formula loge(RAWoto) = 0.7244·loge(RAWscale) + 0.0751·loge(RAWscale)2. Our study comprises a necessary step towards extracting and comparing longitudinal growth data over the entire time series of archived Haddock scales (1931–1993) and otoliths (1994–present) to improve understanding of decadal drivers of growth patterns in this fish stock. Historical longitudinal growth data for exploited stocks are currently underutilized despite their high potential value, given that such data do not confound growth and mortality the way population‐based age–length relationships do. Mixed archives consisting of multiple growth structures exist not only for Haddock but for many commercial fish species; hence, prior to mining these valuable time series of longitudinal data the comparability not only of age but also of back‐calculated growth estimates between structures needs to be ascertained.

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