Lobster Recruitment Index Project

Measuring GaugeIntroduction: A primary research focus for the FSRS is the American lobster, an extremely important species to the Canadian East Coast fishery. Both fishermen and scientist members have expressed concern over the need for more science in support of lobster management. The FSRS has responded by initiating and participating in a number of research projects. A major focus of the FSRS lobster research program is lobster recruitment.

In the spring of 1999, the FSRS launched a Lobster Recruitment Index Project. During the regular commercial season, fishermen use a particular number of scientific lobster traps to gather information about undersize lobsters intheir area. Volunteer fishermen count, sex and measure the size of lobsters from their science traps and record them in a logbook. They also indicate if lobsters are berried, tagged, and/or v-notched. Participants also monitor bottom temperatures by placing a computerized temperature recorder, or VEMCO minilog, in one of their project traps for the entire lobster season

The project has participants in all Lobster Fishing Areas (LFAs) along the Atlantic coast of Nova Scotia, from LFA 27 to LFA 35 (ranging from Cape Breton to the Upper Bay of Fundy), with over 150 fishermen in total. Each participant fishes two to five project traps, depending on the LFA. These project traps are fished in the same locations each year to minimize location variables. All undersized lobsters are released after they are measured and sexed. In areas that fishermen have chosen to have their recruitment traps to be in addition to their legal limit also have to throw back the legal size lobsters.

Project Objectives: The project is designed to study changes in abundance of juvenile lobsters that will be recruited into the lobster fishery in the upcoming seasons and, as the project continues, allow an index of recruitment to be developed. Lobster fisheries in Atlantic Canada rely heavily on newly-recruited lobsters. Hence, we hope to be able to predict, with some degree of uncertainty, if there will be increases or declines for the commercial lobster fishery.

Standardized Project TrapTrap and Gauge Design: It was decided that all participating fishermen should use a standard trap. The standardized science traps have two 5-inch entrance rings, 1-inch wire mesh, no escape vents, and a biodegradable ghost panel. This design was used to maximize the capture and retention of smaller size lobsters (Figure 1). Fisheries and Oceans Canada (DFO) support this research initiative and supply scientific trap tags for the project traps.

The fishermen use a specially designed gauge to measure the carapace length of captured lobsters within defined size intervals (Figure 2). The size groupings are coded from 1 to 15 and are in 10 mm increments, with the exception of size groupings 8 and 9 which are in 5mm increments to give a clear indication of the number of lobsters just under the legal size limit. In the project logbook fishermen can specify if a captured lobster was above minimum legal size within the size grouping which encompasses the legal limit (which can vary between LFAs in the study region, and over time as new conservation measures are introduced).

2015/2016 Results

2011 Data

For additional information or to become more involved in this FSRS project, please contact the FSRS office at 1-800-226-3777. 

Commercial Trap Survey Project

Lobster Recruitment Trap Project - 2014-2015 Update