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Commercial Fisheries News
Volume 37 Number 11
July 2010
Lobster reference points now color-coded
ALEXANDRIA, VA – The Atlantic States Marine Fisheries Commission’s (ASMFC) American Lobster Management Board has adopted new reference points to monitor the health of all three of the region’s lobster stocks – Gulf of Maine, Georges Bank, and Southern New England.
The new stock status measurements utilize the increasingly familiar “traffic light” concept but in a more detailed way. The Southern New England stock will continue to be measured by the standard green, yellow, and red colors, but the Gulf of Maine and Georges Bank stocks now will be sized up against four colors with the addition of orange.
Furthermore, each color is associated with a percentile bracket ranging from below the 25th to above the 75th.
The board adopted this new system during its May 3 meeting based on advice from the American Lobster Technical Committee (TC).
The new reference points were established through Addendum XVI to Amendment 3 of the interstate lobster plan. The addendum also includes exploitation reference points to determine the level of fishing pressure on each stock, as well as mechanisms to more easily update reference points in the future based on new stock assessment information.
Lobstermen naturally tend to pay more attention to management implications rather than the biological reference points themselves, but on a technical level, this new color-coded system marks a significant change in how biologists view stock status.
Different targets
For the Gulf of Maine and Georges Bank stocks, the use of the colors to gauge stock abundance is straightforward and easy to grasp.
Green is good. It’s the “target” zone – “above the 75th percentile” – and the best place to be. Yellow is cautionary with abundance being below the desired target level. Orange is super-cautionary, approaching an undesirable condition. And red is flat-out bad, the bottom line “limit” that’s below the 25th percentile. Red is the “stop” light where serious management action must be taken.
The lobster board easily determined that the new four-color approach was appropriate for the Gulf of Maine and Georges Bank, but it had concerns about setting an abundance target in the 75th percentile “green” zone for Southern New England since the stock there is currently at very low abundance.
Some board members said that, under present environmental conditions, the Southern New England stock may never be able to reach historical levels, so setting unrealistically high targets for stock rebuilding would merely result in failure.
In the end, the board voted to set the “interim target reference point” for Southern New England at the “median” or 50th percentile level, but it kept the 75th percentile standard for the Gulf of Maine and Georges Bank.
GOM, GB colors
Here is a more detailed explanation of the new color-coded reference point system to measure abundance levels for the Gulf of Maine and Georges Bank stocks. Each color is associated with one of the following four percentile brackets: 75% and above; 50% to less than 75%; 25% to less than 50%; and below 25%.
Green – This is the most desirable “target” color. It means that recent abundance, as measured against the 1982-2003 reference period, is “at or above the 75th percentile,” which is as good as it gets under the new reference points.
Both the Gulf of Maine and Georges Bank lobster stocks currently fall into the “green” zone for abundance, which, under ASMFC terminology, means they are in “favorable” condition.
Yellow – This color means recent stock abundance is somewhere between the 50th and 75th percentiles. It is a cautionary category that calls for extra stock monitoring.
Orange – Orange indicates that the stock is approaching a worrisome abundance level, ranging between the 25th percentile to less than the 50th percentile. Like in the yellow zone, orange calls for extra stock monitoring. And
Red – Red means the stock is under the rock-bottom limit, which means it is below the 25th percentile. In this case, action is required to rebuild the stock.
TC suggestion
The TC had recommended a second layer of review for the yellow and orange zones. If a stock should happen to fall into one of these cautionary categories, the TC said biologists could look at two other independent stock indicators: a spawning stock index, possibly based on trawl surveys or the number of mature lobsters being caught; and a young-of-the-year index, possibly based on settlement surveys or postlarval surveys.
For the yellow zone, the TC suggested that management action would be needed if the spawning stock index and the recruitment indices fell below the 25th percentile in three of the last five years.
For the orange zone, the TC suggested that management action would be needed if the spawning stock index or recruitment indices fell below the 25th percentile in three of the last five years.
TC Chairman Carl Wilson of the Maine Department of Marine Resources (DMR) said of the indicators, “If those are crashing, that’s telling you something.”
The board, however, did not adopt this additional review level or identify any potential management actions.
Said board member Dave Simpson, director of Connecticut’s Marine Fisheries Division, “We’re not there yet.”
Southern New England
The debate over Southern New England, which was led by Simpson, was far more complicated.
First, Simpson vehemently opposed using the word “depleted” to define a stock in the red zone, as was initially proposed by the TC.
“Depleted” by definition means “used up,” and even though the Southern New England stock is at an extremely low abundance level, it isn’t “used up” by any means, Simpson argued.
“It’s not an appropriate term,” he said. “You don’t want to be below 25%, but in and of itself, it doesn’t mean anything. You have to look at it in terms of the other indicators.”
Simpson offered up a motion – to which the board eventually agreed – to replace the term “depleted” with “limit reference point” to describe the red zone.
“The limit reference point is the floor you never want to go under,” Simpson said. “You need to take action if you get there.”
SNE median target
Second, Simpson pushed hard to win board support for adopting a different “target” abundance level for the Southern New England lobster stock that was different from the 75th percentile used for the Gulf of Maine and George Bank.
“We cannot achieve the 75th percentile given the current recruitment conditions, so to go forward to the public with unachievable goals sets us up for failure,” he said. “No one can expect us to achieve the 75th percentile for Southern New England – with or without a fishery – but we could at least think about achieving the median if we set very significant measures.”
Board member and Maine DMR Commissioner George Lapointe expressed some concern about the proposal.
“I would rather have the TC say what we need to do to reach the median than to change the reference points,” he said.
“Maybe we need something that’s more like the Magnuson-Stevens Act where if you can’t rebuild within a specified timeframe, then you get more time. But don’t change the target,” Lapointe said.
Board Chairman Mark Gibson, deputy chief of the Rhode Island Division of Fish and Wildlife, said he viewed the percentile target as a goal post.
“It’s the bar at which you claim victory,” he said. “It’s more realistic that we’ll reach the 50th percentile. My thinking on this is that it’s simply how high the goal post is.”
Under this “median” approach, the Southern New England stock would be judged against three colors instead of four: red, which is where stock abundance currently sits in the less than 25th percentile zone; yellow, which is the cautionary zone between the 25th and 50th percentiles; and then the green “target” zone, which is above the 50th percentile.
In the end, the board agreed to adopt the “median” approach for Southern New England, recognizing that the new reference points likely would be modified again after the next stock assessment. The TC recommended updating the stock assessment every five years to determine stock status.
Fishing pressure
The board also agreed to adopt a second set of reference points to gauge exploitation, meaning fishing pressure.
Like abundance, exploitation will be viewed in terms of green, yellow, orange, and red percentiles but, for ASMFC, fishing pressure is secondary for lobsters when compared to abundance.
The TC said in a memo to the board, “The exploitation reference point is designed to be a conditional target as exploitation has remained relatively stable in all areas over a wide range of abundance during the reference period.”
The TC said it recommended the board take action only “if exploitation falls above the 75th percentile,” which in this case is the red zone. None of the three stocks is in the red zone for exploitation.
It takes a minute to think this through because the traffic light signals are flip-flopped for exploitation compared to abundance. Being in the red zone for abundance means you are at a very low stock level that’s below the 25th percentile, but for fishing pressure, being in the red zone means you are above the 75th percentile because effort is extremely high.
If exploitation is in the yellow or orange zone, the TC recommended that the board monitor the situation and go back and look at abundance levels to determine if management changes are needed.
So, for example, fishing pressure could be in the orange zone, which normally would be troublesome, but if abundance at the same time was in the green zone, then it might be OK.
For more information about the new reference points or lobsters in general, call ASMFC lobster plan coordinator Toni Kerns at (202) 289-6400. Her e-mail address is <tkerns@asmfc.org>.
Janice M. Plante
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