First published in Landings, May, 2016.
The Lobster Quality Tour 2016, organized by the Maine Lobstermen’s Association and the Maine Lobstermen’s Community Alliance, brought Prince Edward Island lobster veterinarian Jean Lavallée to more than 200 lobstermen along the Maine coast during one week in April. Lavallée spoke in each of the state’s seven lobster zones about the unusual physiology of the lobster and commonsense practices lobstermen can employ to ensure the highest-quality catch regardless of the number of pounds hauled each day.
Lavallée began each workshop by explaining the odd way a lobster’s body works. For example, a lobster’s kidneys are located just behind the eye sockets. They excrete urine from small holes behind the eyes. “That’s how they talk to each other, from certain chemicals in their urine,” Lavallée said.
A lobster may appear to be as armored as a tank, yet its internal structures make it prone to injury. For example, a lobster’s nerve cord runs down its belly, without the protection of vertebrae. A cut from another lobster or a rough toss by a lobsterman can sever that cord, resulting in paralysis of the lobster’s tail and eventual death. A lobster’s heart is on its back, where the carapace meets the tail. Whack a lobster on the back and it’s likely the heart will rupture. Furthermore, unlike a human being, a lobster has a semi-open blood circulation system. That means the heart pumps blood through ever smaller arteries until finally the blood vessels simply spill the blood into the animal’s tissues; it doesn’t recirculate. “The tissues are bathed in blood all the time. As soon as the shell is broken, then the blood comes out,” Lavallée explained. Lobsters have a powerful clotting system, which prevents something like a V-notch from harming them. But if they suffer serious injuries, they can bleed to death.
When a lobster is taken out of the water, its many gills will collapse, like the sodden pages of a book soaked in water. But it has a method for staying alive on dry land. It captures water in its gill chambers to maintain a thin layer of seawater over those gills. Oxygen from the air will enter through this layer, allowing the gills to work at about 10% efficiency compared to 100% in salt water. “A lobster will last out of the water for two, three days as long as the lobster doesn’t do any work, like fighting,” Lavallée said. The problem for the lobsters is that CO2 and ammonia wastes build up in their blood; if they stay out of water too long, those wastes will kill them.
Molting is the most vulnerable time for a mature lobster. A molt is triggered by water temperature and length of daylight but also by the presence of other molting lobsters. “The males will molt within two to four weeks of each other. The females stagger their molt,” Lavallée said. When a lobster gets ready to molt, often its shell gets thin and crackly to the touch. That is because the animal is drawing calcium and other minerals from its shell to store in nodules, called gastroliths, in its stomach. After the molt, it can reabsorb those minerals to strengthen its shell.
A lobster stops drinking water in order to shrink the mass of its tissues just before it molts. During that time, proteins in its blood increase as the blood becomes thicker. To molt, it will suddenly drink a lot of water to crack the old shell. The lobster then drinks even more water to bulk up in size while its new shell is still soft. “That means its blood proteins will be low. That tells you that the lobster hasn’t recovered from its molt yet,” Lavallée said.
When it comes to what makes a high-quality lobster, Lavallée pointed out that the answer depends on your point of view. In his opinion, the best prices are paid for intact lobsters with a hard shell, low expected shrink rate, high meat yields and maximum shippability.
Together, Canada and the U.S. land more than 350 million pounds of lobster annually, light years ahead of other lobster fishing countries like Australia, Indonesia and Chile. However, the shrink rate in the U.S. and Canada is also very high, from 5% to 10% each year. In absolute numbers, “That’s more than most of these other countries land in one year!” Lavallée said. “That’s a lot of lobsters.”
Careful handling of lobsters, based on a better understanding of their anatomy and biology, can reduce losses and save millions of dollars.
“Quality is like a one-way gas tank. You can take the quality out of the lobster but it’s very hard to put it back in,” he said. All sorts of things stress out a lobster, weakening it over time. Rapid hauling from the bottom is one stressor. Researchers looked at lobsters hauled at the typical 500-feet-per-minute rate and those hauled more slowly, at 80 feet per minute. “They [the latter] were more vigorous,” he said. Other things, like variations in temperature, the amount of oxygen in the tank, exposure to fresh water or ice, all cause stress on the lobster. “Stress has a snowball effect on lobsters. They don’t recover from it as quickly as we do.”
Minor injuries to lobsters also add up to lost money, he said. Practices such as tossing lobsters, handling traps roughly, and overstuffing, dropping or banging crates can increase limb loss and bleeding. “Lobsters that bleed lose fluid. That means they lose weight. When you think about it, a one- to three-pound loss of weight per every 100 pounds caught is about $10 per crate. Think of the number of crates you’ve landed in your life,” Lavallée said.
Lavallée offered simple suggestions such as “one hand, one lobster” when handling lobsters and treating them as if they were eggs. “It doesn’t take a lot of money,” he said. “It doesn’t take a lot of time.”
Slow down your hauler. Bring the trap over the rail smoothly and don’t bang it around so that lobsters’ small legs are snapped off. Don’t throw the shorts back into the water while the boat is moving. “It’s like hitting concrete. It will snap their claws off,” Lavallée explained.
He advises placing lobsters in the crate all going the same way. At the dock, wharf workers should lift the crate horizontally by two handles, not by one, which smashes all the lobsters over to one side. Don’t drop the crate. Don’t over pack it either because the lobsters will inevitably stab each other with their nose or horns.
“Quality is as important to the processing sector as it is to the live sector,” Lavallée emphasized. “Processors live and die by meat yield. They want a high-quality non-injured lobster to start with.”Category: Programs