Lobster T.V.

Lobster Trap Video (LTV)

What is LTV (lobster trap video)?
LTV consists of a traditional two parlor lobster trap equipped with a time-lapse video recording system. We are able to obtain 24-48 continuous hours of video during each soak, depending on whether we use lights and record at night. We can then take these videos and analyze the movements and interactions of the lobsters around the trap.

LTV was first developed as part of a UNH Ocean Projects course, and then Sea Grant funds were used to improve it. If you would like a short video about this project, send us $5 to cover the cost of copying of the tape and postage. If you would like to read a publication about LTV, coauthored by Steve Jury, go the the Publications section of this site.Click on images to enlarge.

Current Projects
Currently, we are comparing data collected with LTV, traditional traps, and diver surveys to determine why catch in traps does not accurately correlate with the density of lobsters on the ocean floor. We are also using ultrasonic tracking in association with LTV to determine the area fished by a trap.

Our goal is to develop a more accurate way to easily and accurately assess the actual abundance of lobsters on the ocean floor. These studies are being carried out at our Wallis Sands study site, adjacent rocky habitats and waters off of Newcastle Island (see the following sections and the Ultrasonic Tracking Project for details).

Graduate students launching LTV
Graduate students launching LTV
LTV with lobster inside
LTV with lobster inside
LTV with lobster inside
LTV with lobster inside
LTV on ocean floor
LTV on ocean floor

LTV - Observations/Data

Based on our observations of approximately 24 videos obtained during the summers of 1998-2000, we have drawn a number of conclusions, a few of which are listed below. For more details about these studies see our first manuscript on the subject (Jury and Watson, 2001) in the Publication section of this website.

1. A large number of lobsters approach and enter traps, yet typically we only catch 1-3 per trap haul because the vast majority escape. We estimate that 10% of the lobsters that approach a trap enter, and of the ones that enter, only 6% are caught. Over 75% of the lobsters that escape the trap do so through the entrance. Video 1, on the right, shows a lobster escaping through the entrance to the kitchen.

2. Lobsters are very active around traps during the day, as well as the night. This confirms other field observations indicating that lobsters in their natural habitat are not as strickly nocturnal as previously thought.

3. Agonistic encounters around traps appear to limit entry and stimulate exits. Video 2 shows a large lobster chasing away smaller lobsters and then entering the trap. Small lobsters are very hesitant to enter, while larger lobsters tend to move right in like the one shown in this video.

4. Once in the trap, lobsters tend to "defend" the resource. Video 3 demonstrates this behavior. This also limits entry and it is probably one of the main behaviors that lead to trap "saturation".

LTV Study Site - Wallis Sands

We focused our initial studies with LTV at the Wallis Sands study site because it is dominated by a sandy substrate which makes it very easy to obtain accurate estimates of lobster density using SCUBA divers (see images). In addition, there is a seasonal fluctuation in the density of lobsters so that we can obtain catch and LTV data over a range of densities. Click to enlarge images.

Currently, most of our work with LTV is taking place in a cover near Newcastle Commons and the UNH Coastal Marine Laboratory. At this location we are using LTV and ultrasonic telemetry to measure the attraction of lobsters to traps. For more information about this study site go to the ultrasonic telemetry pages of this website.

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