V-Notching lobsters remains valuable tool

First published in Landings, January, 2013.

Since 1982, the MLA has been conducting an annual V-notch Survey. Early to mid-October was chosen as the annual survey week because there has historically been a good run of egg-bearing and V-notched lobsters at that time and the weather is still good enough to haul regularly. During any two days of the survey week, lobstermen record the number of eggers, V-notch, oversize and short lobsters on a data card. The results from this survey have been used to track the effectiveness of v-notching as a conservation measure to protect lobster brood stock in the Gulf of Maine.

The survey took place in 2012 between October 10 and 16, and marked the 30^th year of v-notch data collected by the MLA. This year saw one of the lowest number of participants, but the highest number of v-notched lobsters recorded.

“We need to make sure v-notching continues,” said Kathleen Reardon, director of the sea sampling program at Department of Marine Resources (DMR). The practice of v-notching as we know it today began in 1975. Long ago, in 1872, the Maine legislature passed a law prohibiting the catching egg-bearing female lobsters. In 1903, the Maine Sea and Shore Fisheries Department (which became the Department of Marine Resources in 1973) further protected females by buying them from lobstermen at 15% over the market price and then releasing them into state waters. In 1917, the state decided to identify those seed lobsters by physically marking them. Each female lobster purchased by the state had a hole punched through the middle flipper before release. Those lobsters were state property. Anyone selling a punched lobster was fined $50, a significant penalty in those days.

In 1948, the state began marking its female lobsters with a V-notch in the middle flipper. It turned out that the punched lobsters were having a hard time molting with a hole in their middle flipper. Egg-bearing females still could be caught by licensed lobstermen who then sold them to the state to go to a lobster hatchery or to be released. A revised Lobster Seed Program to purchase and release female lobsters remains in effect today.

The MLA began its v-notch survey to prove that protecting egg bearing females through v-notching was a legitimate conservation measure. At that time, regulators were seeking to increase the gauge and did not consider v-notching a worthwhile conservation measure.

In 1985, 36% of the MLA survey participants were in zone B; in 2012 that fell to 22%. Participation has declined steadily over the years, as has the number of traps hauled. Overall, however, the volume of lobsters hauled during the survey week hasn’t changed much. The lowest number of pounds recorded was in 1986, which was also a year with very low survey participation (90 lobstermen). In 2012, there were 46 participants with a reported 43,724 pounds hauled.

So what does this all mean? More pounds of lobster were hauled by fewer people this year than in the past 30 years, which is not surprising given the record landings. And v-notching has likely contributed to the industry’s success. “V-notching allows lobsters a chance to molt and reproduce [resulting in more lobsters],” emphasized Reardon. “V-notching is making a difference.”

Reardon has yet to analyze data from this year’s sea sampling trips, but she has run the observed discard rates seen in sea sampling over the past five years in the University of Maine Lobster Stock Assessment Model to evaluate the importance of v-notching. “The sea sampling data shows a 20% discard rate in all females at legal size (3 ¼ in). That rate went up to about 80% in select sized female lobsters. The discard of these otherwise legal-sized females is due to the presence of a notch or eggs. Those numbers show there is high compliance,” Reardon said. The University’s computer model predicts recruitment into the fishery decades out and makes those predictions using three scenarios: the fishery with v-notching, without v-notching, or at a reduced rate of v-notching. The model results imply that a predicted high and sustainable recruitment rate is very dependent on the present rate of v-notching, Reardon said.

MLA v-notch data indicates that in 1985, only 15% of lobsters in a trap were v-notched. In 2000, that climbed to 45%. Most of those notched lobsters did not have eggs, supporting Reardon’s observation that there is a high compliance rate in discarding egged and notched females. She has also heard from many lobstermen that there have been more shorts with eggs this year than in the past. “I looked at the data and the percent of short lobsters with eggs does seem to have increased slightly in the eastern part of the state. But this is only a preliminary analysis,” Reardon said. She said this could be a result of water temperatures increasing. Data from MLA’s survey support this finding. In 1990, 10% of egged lobsters recorded were shorts. By 2005 that had increased slightly to 11%. In 2012, 15% of egged lobsters recorded were shorts.

To ensure a continued healthy population of lobsters, V-notching remains essential. A mature female lobster may carry up to 100,000 fertilized eggs upon her abdomen and while not all of those eggs will survive to maturity, they do lead to more lobsters in the Gulf of Maine.