Evaluation of a Fishery Resource Response to a Net-Use Restriction in Saipan Lagoon, Commonwealth of the Northern Mariana Islands

A wide variety of fishing methods is used to harvest coral-reef fishes worldwide, with increasing concerns regarding long-term sustainability. As such, there is a need to determine the degree to which specific fishing methods influence coral-reef fish resources. In 2004 the Commonwealth of the Northern Mariana Islands instituted restrictions on use of gill, drag, and surround nets, limiting use to special exemption for annual fiestas. Historical creel survey data and data from net-use exemptions were reviewed and underwater visual census surveys conducted in southern Saipan Lagoon to assess changes in abundance and biomass from 2004 to 2011. Generalized linear modeling results showed numerical increases in four reef fish families, including Labridae, Scaridae, Mullidae, and the primary target of exempted net-fishing events, Lethrinidae. In addition, mean increases in total reef fish biomass were observed from 2004 to 2011. Positive changes in abundance and biomass of certain coral-reef fish families suggest that decreased fishing mortality via gear restrictions on use of nets can be a useful tool toward the goal of reef fish sustainability in coral-reef ecosystems.