NORTHERN COD RESEARCH

Part of the work of NCSP's egg and larval drift research has been to reconcile this apparent contradiction. At the beginning, there seemed to be three possibilities:

1. Cod spawn more widely across the shelf than the Russian data suggested;
2. Storms or currents sweep the eggs and larvae of cod spawned offshore into inshore rearing habitat;
3. Some of the juveniles found inshore come from inshore spawning;

Five years research and analysis, approaching the matter from several directions, found that all three of these statements are true.

For example, scientists analysed 47 years of trawl survey data and five years of research gillnet data, to find where cod had been caught in spawning condition. This analysis showed that northern cod spawn widely across the Northeast Newfoundland Shelf, the Grand Bank and the outer slope of Hamilton Bank. It also showed that inshore spawning could be much more important than was previously thought.

A CHANGE IN THE RANGE

Stock collapses are often accompanied by a change in the area occupied by a stock. This is well known in pelagic fisheries and proved to be true of adult northern cod in the years leading up to the moratorium in 1992. In the case of young cod, there was no evidence of a contraction of range along the coast, despite the marked decline in numbers. That is, young cod were present in the same coastal areas as they were in the 1960's, but they were much more thinly spread.

However, there is evidence that the range of young cod has contracted in the other direction. As the historical data shows, juveniles were distributed widely over the Shelf when fish were abundant. After the stock collapse, however, most young fish are found inshore, with the youngest found nearer to shore and the older ones farther out.

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