Bluefish, Pomatomus saltatrix, are distributed worldwide and found regionally along the eastern United States in the Gulf of Mexico and from Florida to Maine. The species supports a major recreational fishery and to a lesser extent a seasonal commercial fishery in NAFO Divisions 5 and 6. The ages of 3 334 bluefish were determined using scales from bluefish collected off the U.S. northeast coast during Northeast Fisheries Science Center autumn bottom trawl surveys in 1985 96, a period within which bluefish abundance decreased substantially. This study used length and age data to estimate growth rates by sex and by year. Maturation patterns were examined for the period 199396. The autumn geographical distribution of age-classes 0, 1, 2 and 3+ fish was also analyzed.The oldest bluefish in the study was twelve years old and the largest was 88 cm (fork length). No significant differences were found in growth between sexes or on an inter-annual basis; von Bertalanffy growth parameters for both sexes and all years combined were L inf = 87.2 cm, k = 0.26 and t 0 = -0.93. Incremental growth rates in length showed a significant decrease after the age of two. The median length at maturity was 33.9 cm for males and 33.4 cm for females. The median age at maturity was 1.2 and 1.1 years for males and females, respectively. Younger fish were almost always found inshore and older age-classes tended to be found mostly offshore.
Fork length–total length conversions for haddock Melanogrammus aeglefinus from Georges Bank and pollock Pollachius virens from the Gulf of Maine were developed by linear regression with data from fish caught during gear comparison studies. These conversions were developed to replace previous conversions that were inaccurate or insufficiently documented. Total lengths (TLs) and fork lengths (FLs) were obtained from 216 haddock ranging from 35 to 73 cm TL (median = 57 cm) and 220 pollock ranging from 43 to 107 cm TL (median = 75 cm). The conversion equation for haddock was FL = 0.95 × TL + 0.65. For pollock, it was FL = 0.94 × TL − 0.62. Reciprocal equations were also determined. Received August 27, 2010; accepted February 17, 2011
The use of midwater trawls to harvest Atlantic herring (Clupea harengus) in the Gulf of Maine has been a controversial topic for many years. A majority of the concern revolves around the potential physical disruption of Atlantic herring aggregations and the potential impact on ecological processes and other industries (e.g., other fisheries and eco-tourism) that rely on these aggregations. Preliminary acoustic data collection in fall 2008 using a combination of Simrad ES60 echosounders (38 and 120 kHz) and a Simrad SP90 omni-directional sonar (20–30 kHz) showed promise for quantifying herring aggregation metrics. In this presentation, we report on a pilot study conducted in the summer of 2009 that uses these acoustic systems to quantify and describe herring aggregations before and after midwater trawling with a pair of fishing vessels. We used a systematic grid design to survey an area continuously for 24 h both before and after pair trawl fishing over multiple fishing trips. We report on the efficacy of using acoustic systems to quantify the potential impacts of fishing on herring aggregations and discuss the next steps to fully evaluate these potential impacts at spatial and temporal scales relevant to the fishery.
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