Long-term trends in lobster populations in a partially protected vs. no-take marine park

Published source details 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.
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This study is summarised as evidence for the following.

	Action	Category
	Designate a Marine Protected Area and prohibit commercial fishing Action Link
	Designate a Marine Protected Area and prohibit all types of fishing Action Link

Designate a Marine Protected Area and prohibit commercial fishing

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.

(Summarised by: Anaëlle Lemasson)
Designate a Marine Protected Area and prohibit all types of fishing

A replicated, before-and-after, site comparison study in 1977–2005 of 10 rocky sites in the South Pacific Ocean, northeastern New Zealand (Shears et al. 2006) found that during the 22 years after implementing a protected marine park prohibiting all fishing (no-take), abundance and biomass of spiny rock lobsters Jasus edwardsii increased and became greater than at adjacent fished sites. Before designation, lobster abundance and biomass were similar inside (4–19 lobsters/transect; 0–3 kg/transect) and outside (0–7 lobsters/transect; 0.1 kg/transect) the park. Legal-size lobsters (>95 mm carapace length) in the park were 10.9 times more abundant after implementation (6–32 lobsters/transect) compared to before (0–5 lobsters/transect), with biomass 25 times higher (before: 0–3; after: 14–41 kg/transect). There was no change in abundance of sublegal-size lobsters inside the park. No legal-size and only 0–7 sublegal-size lobsters/transect were present outside the park after implementation. Tāwharanui Marine Park was established in 1981 (implemented 1983). Between 1977 and 2005, five no-take sites and five fully-fished sites outside the park were surveyed annually. Divers counted all lobsters and visually estimated the size and weight of legal-size lobsters along a 50 × 10 m fixed transect at each site.

(Summarised by: Anaëlle Lemasson)