There is fresh news out of the National Oceanic and Atmospheric Administration regarding the status of Gulf of Maine cod, and the outlook isn’t good. Atlantic cod, the mainstay of New England fisheries for more than 400 years, is now at 3 percent to 4 percent of its target levels.

On the heels of a dramatic 78 percent reduction in fishing quotas that went into effect in 2013, it is likely that further, even more severe, fishing restrictions will be needed to revive this iconic stock.

Cod landings and biomass in the Gulf of Maine have fluctuated dramatically for as long as we have records. Some of this is because of environmental conditions, and some is because of past fishery management decisions that led to decades of overfishing.

Today, despite a wealth of survey data, a sophisticated process to estimate the number of fish and determine catch levels and a fishery that now operates well within these limits, we find ourselves with a cod stock that remains drastically overfished and unresponsive to our best rebuilding efforts.

This story may sound familiar. In 1992, the Canadian government called for a moratorium on cod fishing in Newfoundland in response to a similar decline in their stocks. The expectation was that cod would respond promptly to this strictest of measures and that fishermen would be back to work within a few years.

Two decades later, Newfoundland cod biomass still remains at relatively low levels. We now know that all cod are not created equal, a fact that becomes all too apparent when populations are low.

One important attribute that distinguishes one cod from another is age. Ideally, cod in the North Atlantic should live about 20 years, but it is now rare to find cod older than 5 to 6 years. These younger, smaller female cod spawn fewer and poorer-quality eggs than their older, larger counterparts.

They also typically only spawn once per spawning season, if at all. Older cod tend to spawn in several batches throughout the spawning season. This batch spawning is like diversifying an investment portfolio; there is a good chance that at least one will encounter the conditions it needs for success.

It is also now recognized that the Gulf of Maine cod stock was once comprised of a great diversity of spawning groups that utilized different spawning grounds during different seasons. This is no longer the case, and most spawning is confined to the western Gulf of Maine.

All this is to say that cod have evolved to hedge their bets when dealing with variable ocean conditions in the Gulf of Maine, and we now find ourselves in a situation with all our eggs in one basket. The fish are young and getting younger; spawning locations are few and getting fewer; and spawning behavior is increasingly uniform. This erosion of diversity within the cod stock presents a challenging starting point for the recovery of cod from their current all-time low.

So where do we go from here? There will undoubtedly be reductions in cod quotas over the coming months in response to the latest interim assessment. However, in order for cod to recover, managers must focus on rebuilding attributes of the stock that have been severely reduced.

Great work has been done in Massachusetts state waters to protect known spawning locations by closing these important areas during the spawning season. This work should be continued and expanded.

We have also found more old, large cod inside the few regions in the Gulf of Maine that restrict fishing. These closed areas, which were established in the 1990s to reduce groundfish mortality, may be our best tool for protecting older, larger females, and current plans to alter their boundaries should be considered very carefully in light of the current cod situation.

Finally, it may be that warming ocean conditions will make it harder and harder for cod – a sub-Arctic species at the southern end of its range – to exist in the Gulf of Maine. Efforts to protect diversity within the stock should help buffer cod against highly variable climate and ocean conditions, which are likely to intensify in the future.

In doing so, we may help to build a stock that is much more resilient to adverse conditions, making the road to recovery a little shorter.

— Special to the Press Herald


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