Lobster Egg Production and Larval Drift Potential in the Tickles MPA
There has been increasing use of closed areas as a conservation tool for a wide range of species including lobster. Empirical evidence to evaluate the efficacy of closed areas, especially over broader spatial scales of the closed area itself, is generally lacking. In Newfoundland, there are areas closed to lobster fishing at Eastport and in the Tickles Marine Protected Area (MPA); voluntary bans on fishing for lobster exist at other sites. Area closures are often popular with fishers, ecologists and conservationists because they have the potential to yield positive changes to populations within and beyond the boundaries of the protected area. Research suggests that within closed areas adult mortality may be lower, growth rates could be elevated, and fecundity could be greater, however, the influence of closed areas on adult lobster populations has not been evaluated in the Tickles MPA. The goals of this project were to (1) determine the size-fecundity relationship for female lobsters in the Tickles MPA (2) compare lobster larval abundance inside and outside closed areas of the Tickles MPA and (3) investigate larval drift patterns in the Tickles MPA with drifters. The results of this project are insufficient to test the hypothesis that lobster populations within the Tickles closed areas produce more eggs per individual than populations outside closed areas, but there is some suggestion in the preliminary data collected to date that supports this idea. Areas closed to lobster fishing may be sources of lobster larvae for the Tickles MPA. This study found that large lobsters produce proportionately more eggs than smaller individuals, and the largest lobsters sampled (though sample size was small and differences were not statistically different) were collected in closed areas. Therefore, lobster populations inside closed areas compared to those outside may produce more eggs. V-notching may also contribute greatly to total lobster egg production because of the logarithmic relationship between number of eggs and lobster size and the positive effect notching has on allowing lobsters to grow to a larger size. No lobster larvae were collected during sampling in the Tickles MPA during 2005, highlighting that local influences on the horizontal and vertical distributions of lobster larvae are not known and require more intensive sampling effort. The results of drifter studies suggest that lobster eggs and larvae produced in Glovers Harbour remain nearby. However, the proportion of eggs produced at Mouse Island that seed sites in the Tickles MPA may depend on the timing of larval hatch and larval development rates in relation to physical processes.
01 Jan 2005
Fishing, hunting and trapping
Department Of Fisheries And Oceans – Oceans Branch, Harris Centre
Strategic Research Theme
Oceans, Fisheries and Aquaculture