Research Document 1998/53

Evaluation of the Emerald/Western Bank juvenile haddock closed area

By K.T. Frank and J.E. Simon

Abstract

A juvenile haddock closed area was established in Div. 4W in 1987 with the objective to protect incoming recruits and allow the stock to rebuild. The areas chosen for closure included Emerald and Western banks; these areas contain relatively large and persistent aggregations of young haddock as revealed by the July research vessel survey series. Initially, it was decided that fixed gear fisheries could fish inside the closed area because these gears were believed to catch older fish than that of mobile gear. Such was not the case and fixed gear fishing was prohibited inside the closed area in 1993. Ten years have now elapsed since the establishment of the closed area and a review of the impact of the closure has been requested by industry and managers. The current review focused on evaluation of changes in abundance and mortality rate of haddock inside the closed area and in contiguous areas subjected to fishing. Several other groundfish species have also been examined for changes in abundance inside the closed area and in relation to adjacent areas. The most significant findings were as follows: i) haddock yearclasses inhabiting the Emerald/Western banks region that were in existence during the imposition of the closed area experienced lower mortality in comparison to adjacent areas, ii) juvenile mortality was highly variable and the expected trend of declining mortality coincident with the establishment of the closed area was not discernable, iii) a declining trend in adult mortality preceded the imposition of the closed area and, on average, adult mortality was higher prior to the mid-1980s and lower thereafter, in both the closed area and adjacent reference areas, iv) the eastern boundary of the closed area divides the distribution of haddock in Div. 4W which complicates the interpretation of the impact of the closed area, and v) American plaice was more abundant inside the closed area after the imposition of the closure relative to the adjacent reference areas and this species is poorly selected by fixed gear directing for haddock and would have been protected from fishing inside the closed area for over a decade. Although no effects have been detected on juvenile haddock mortality in the closed area it does not rule out the potential beneficial impacts on the stock.)

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