Marine Protected Areas (MPAs) are designed to enhance biodiversity and ecosystem services. Some MPAs are also established to benefit fisheries through increased egg and larval production, or the spillover of mobile juveniles and adults. Whether spillover influences fishery landings depend on the population status and movement patterns of target species both inside and outside of MPAs, as well as the status of the fishery and behavior of the fleet. We tested whether an increase in the lobster population inside two newly established MPAs influenced local catch, fishing effort, and catch-per-unit-effort (CPUE) within the sustainable California spiny lobster fishery. We found greater build-up of lobsters within MPAs relative to unprotected areas, and greater increases in fishing effort and total lobster catch, but not CPUE, in fishing zones containing MPAs vs. those without MPAs. Our results show that a 35% reduction in fishing area resulting from MPA designation was compensated for by a 225% increase in total catch after 6-years, thus indicating at a local scale that the trade-off of fishing ground for no-fishing zones benefitted the fishery.

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Co-operation in the management of shared fish stocks is often necessary to achieve sustainability and reduce uncertainty. The United States of America (USA) and Mexico share a number of fish stocks and marine ecosystems, while there is some binational co-operation in scientific research, unilateral management decisions are generally the rule. We present a case study using the giant sea bass (Stereolepis gigas, Polyprionidae) to highlight how these management and research asymmetries can skew national perceptions of population status for a fully transboundary species.Scientific publications and annual funding related to giant sea bass are 7x and 25x higher in the USA, respectively, despite the fact that 73% of the species' range occurs in Mexico. Conversely, annual fishery production and consumptive value of giant sea bass in Mexico are 19x and 3.5x higher than in the USA, respectively, while the nonconsumptive value related to dive ecotourism is 76x higher in the USA. These asymmetries have generated a distorted view of the population status of the giant sea bass across its entire range. This and other factors related to historical fishery dynamics and policy must be accounted for when assessing population status, and subsequent appropriate management responses, across geopolitical boundaries. | 1393 RAMÍREZ-VALDEZ Et AL. 2.1. Asymmetry in scientific research 1394 2.2. Fishery and management trends 1395 2.3. Spatial patterns of the contemporary fishery 1397 2.4. Asymmetry in economic value 1397 3. RESULTS 1397 3.1. Asymmetry in scientific research 1394 3.2. Fishery and management trends 1399 3.3. Spatial patterns of the contemporary fishery 1401 3.4. Asymmetry in the economic value 1401 4. DISCUSSION 1402 4.1. Asymmetry in scientific research 1403 4.2. Fishery and management trends 1404 4.3. Spatial patterns of the contemporary fishery 1405 4.4. Asymmetry in economic value 1405 5. CONCLUSIONS AND FUTURE DIRECTIONS 1406 ACKNOWLEDGEMENTS 1407 CONFLICT OF INTEREST 1407 AUTHOR CONTRIBUTION 1407 DATA AVAILABILITY STATEMENT 1408Peer-reviewed papers -Information exclusively from the USA 39Peer-reviewed papers -Information exclusively from Mexico 13Peer-reviewed papers -Information from both the USA and Mexico 4Total unique GSB-centric papers 21 GSB-centric papers -Data exclusively from the USA 21 GSB-centric papers -Data exclusively from Mexico 0 GSB-centric papers -Data from both the USA and Mexico 3 Notes: WS, ISI Web of Science; GS, Google Scholar; GSB-listed, Papers that mention GSB; GSB-centric Paper, Papers that are focussed on GSB. Giant sea bass and black sea bass are common names in English used in the literature. Mero gigante and pescara are common names in Spanish (sensu Page et al., 2013).a Pescara is also a noun in Italian.

The conservation benefits of marine reserves are well established but their contribution to adjacent fisheries via spillover is less certain and context‐dependent. Theoretical predictions do not always match empirical evidence from individual reserves, so carefully designed studies are essential for accurately assessing spillover and its contribution to fisheries. Biomass buildup within reserves, and spillover from reserve borders, also usually takes time to develop. In 2003, a network of no‐take marine reserves was established in the Northern Channel Islands (NCI) of southern California (CA) to conserve biodiversity and to eventually enhance local fisheries through spillover of larvae, juveniles, and adults. The reserve network impacted the local CA spiny lobster (Panulirus interruptus) fishery by removing about 20% of fishing grounds in the NCI. In 2008, a collaborative fisheries research effort detected substantial lobster population increases within reserves, and an indication of the possible spillover of adult lobsters across reserve borders. To estimate whether and how much populations within reserves, and spillover from reserves, have increased through time, we repeated the sampling program 10 years later in 2018 at two of the three original reserves. Scientific trapping was conducted prior to the fishing season along a spatial gradient beginning deep within the reserves to reference sites located outside (≥2 km) of reserve borders. Results showed that legal‐sized lobster abundance in traps (catch per unit effort) increased by 125%–465% deep inside reserves, and by 223%–331% at sites near to reserve borders, and by nearly 400% just outside of reserve borders over the 10‐year period, thus indicating a substantial increase in spillover across reserve borders. A similar pattern was observed in lobster biomass caught in traps at the two reserves. This study demonstrates how spillover scales with biomass buildup and that collaborative fisheries research can be used to assess the efficacy of marine reserves as fishery management tools worldwide.