LobSense is the user-friendly version of the egg-per-recruit model that has been used for the last ten years to determine whether the fishing mortality rate on a particular lobster stock is above or below the official definition of overfishing. A lobster stock is classified as overfished if the fishing mortality rate is higher than that which would allow the average female lobster to produce 10% of the eggs that she would if she were allowed to live out her natural lifespan (F10%).
LobSense also calculates the yield-per-recruit that a stock will produce at any given fishing mortality rate. A recruit is a young lobster entering the fishery. If all of the lobsters are caught at a small size, the yield-per-recruit will be less than it would be if the lobsters are caught at a slower pace (lower fishing mortality rate) and allowed to stay in the water longer and grow larger, on average. This assumes that the lobsters will not die from other causes while waiting to be caught. LobSense can determine the fishing mortality rate that will maximize yield per recruit, depending on the natural mortality rate.
Because lobsters bring a different price per pound depending on their size, LobSense also allows the user to assign different prices by month to different size classes of lobsters. In this way LobSense can calculate the optimum fishing mortality rate and yield-per-recruit on an economic basis as well as a poundage basis.
Although the different lobster stocks on the Atlantic coast of the U.S. and Canada have different life history characteristics (primarily growth rates and age of sexual maturation), LobSense currently uses one set of average characteristics. The general results are likely to be representative of most lobster stocks, but precise results would require that the appropriate populaton parameters be entered into the model for the stock under consideration. This is currently being done for the three major stock areas. If you would like to obtain the updated population parameters when they become available, please let me know.
Lobsense can be downloaded by clicking on the hyperlink at the bottom of the page. If you have questions or suggestions concerning LobSense, please contact Dick Allen at rba@FisheryConsulting.com, or call (401) 789-1463.
LobSense was created with funding from the Pew Fellows Program in Marine Conservation and utilizes a model developed by Josef Idoine at the Northeast Fisheries Science Center of the National Marine Fisheries Service at Woods Hole, MA. The graphic user interface was created by Paul Gaertner. Technical advice was provided by Richard McGarvey.
