Designate a Marine Protected Area and prohibit commercial fishing

Supporting evidence from individual studies

1. A replicated, before-and-after study in 1977–2005 of nine rocky seabed sites in the South Pacific Ocean, north-eastern New Zealand (Shears et al. 2006a) found that over the 12 years after implementing a marine park prohibiting commercial fishing but allowing the recreational harvest of spiny lobsters Jasus edwardsii, abundance and biomass of lobsters inside the park did not increase. Average lobster abundance was statistically similar before (7–47 lobsters/transect) and 12 years after implementation (4–9). Average biomass of legal-size lobsters (>95 mm carapace length) was similar before (1–3 kg/transect) and after implementation (0–1). Mimiwhangata Marine Park was established in 1984 (implemented 1993). Between 1977 and 2005, nine sites inside the park were surveyed annually. Divers counted all lobsters and visually estimated the size and weight of legal-size lobsters along one 50 x 10 m transect/site.

    

   A replicated, site comparison study in 2003 of 17 rocky seabed sites in the South Pacific Ocean, north-eastern New Zealand (Shears et al. 2006b) found that 10 years after implementing a marine park prohibiting commercial fishing but allowing the recreational harvest of spiny lobsters Jasus edwardsii, abundance and size of lobsters were not higher inside the park compared to outside where fishing occurred. Lobster abundance was not different inside (24 lobsters/transect, of which 8 were legal-sized) and outside the park (28 lobsters/transect, of which 6 were legal-sized). The carapace length of lobsters was not different inside (82 mm) and outside (88 mm) the park. Mimiwhangata Marine Park was established in 1984 (implemented 1993). In 2003, nine sites inside the park and eight fully-fished sites outside were surveyed. Divers counted and visually estimated the size of lobsters along three 50 x 10 m transects/site.

   Study and other actions tested

   Referenced paper

   Shears N.T., Grace R.V., Usmar N.R., Kerr V. & Babcock R.C. (2006) Long-term trends in lobster populations in a partially protected vs. no-take marine park. Biological Conservation, 132, 222-231.

2. A site comparison study in 2011–2012 of two areas in the Caribbean Sea, Mexico (Ley‐Cooper et al. 2014) found that Carribbean spiny lobsters Panulirus argus grew larger in an area where commercial fishing was banned compared to a fished area, and that a high proportion of the lobster population in the unfished area stayed there over the duration of the study and thus remained protected. Lobster sizes were greater in the unfished area (94 mm) compared to the fished area (73 mm). In the unfished area, this corresponded to 99% of lobsters being bigger than the minimum legal catch size (74.5 mm), while in the fished area it corresponded to only 25%. In addition, an estimated 20% of the lobster population occurring in the unfished area moved to the fished area over the duration of the study, thus 80% remained protected inside the unfished area. The study was carried out in a Biosphere Reserve (year of designation unspecified) which restricted commercial fishing to shallow depths (<20 m) and banned it where depths exceed 20 m (see paper for details). In August–September 2011, lobsters were hand-caught from the unfished area, tagged, sized (carapace length) and released in the unfished area (379 in total). During the 2011/2012 fishing season in the fished area, all lobsters caught by fishermen were sized, and tagged lobsters recorded. A tag-recapture model based on the number of recaptured tagged lobsters (20 in total) was used to estimate the percentage of the lobster population moving from the protected to the fished area.

   Study and other actions tested

   Referenced paper

   Ley-Cooper K., De L.S., Phillips B.F. & Lozano-Álvarez E. (2014) An unfished area enhances a spiny lobster, Panulirus argus, fishery: implications for management and conservation within a Biosphere Reserve in the Mexican Caribbean. Fisheries Management and Ecology, 21, 264-274.