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Marine protected areas (MPAs) aim to protect habitats and ecosystems to promote the diversity and health of marine populations. To evaluate the health of fish populations within and outside of MPAs in Southern California, we used flight initiation distance (FID). FID is the distance at which an individual will flee from a perceived predator and is a direct measure of boldness. Lower FIDs are indicative of bolder populations. Lower FID values indicate that fish will have the opportunity to dedicate less energy to fleeing from predators which could then be used for increased foraging. Data was collected from eight locations along the Southern California coast, four in protected areas and four in non-protected areas. FIDs were measured with a sonar-based range finder. All fish species that recreational fishermen could catch were targeted, with a focus on six core species spearfishermen catch commonly. Results showed that all fish sampled in MPAs have significantly lower FIDs than those in non-protected areas. An ANOVA showed no significant difference between different locations of the same protected status. The six core species had lower average FIDs in protected areas, three species had significant differences between protected and non-protected populations, and there was no significant difference in FIDs between species. These results show that Southern California MPAs are promoting healthier fish communities with respect to boldness behavior. This data and methods can be implemented in future projects to expand the range of metrics measured to inform management tools for California’s MPAs and MPAs at large. 

Submarine groundwater discharge (SGD) in high volcanic islands can be an important source of freshwater and nutrients to coral reefs. High inorganic nutrient content is generally thought to augment primary production in coastal systems but when this is delivered via a freshwater vector as is the case with SGD in this study, the effects on productivity are unclear. In the current literature, there is limited evidence for a direct association between SGD and primary productivity of reefs. To elucidate the response of primary productivity to SGD, we conducted spatially and temporally explicit in situ benthic chamber experiments on a reef flat along a gradient of SGD. We found significant quadratic relationships between C-uptake and SGD for both phytoplankton and the most abundant macroalga, Gracilaria salicornia , with uptake maxima at SGD-derived salinities of ~21−22 (24.5−26.6 μmol NO 3 -L −1 ). These results suggest a physiological tradeoff between salinity tolerance and nutrient availability for reef primary producers. Spatially explicit modeling of reefs with SGD and without SGD indicate reef-scale G. salicornia and phytoplankton C-uptake decreased by 82% and 36% in the absence of SGD, respectively. Thus, nutrient-rich and low salinity SGD has significant effects on algal C-uptake in reef systems. 

Abstract Submarine groundwater discharge (SGD) is an important transporter of solutes and fresh water in coastal systems worldwide. In high island systems with a mixed semidiurnal tidal cycle driving SGD, coastal biogeochemistry is temporally and spatially variable. Past studies have shown that SGD covaries with the local species composition, diversity, and richness of biological communities on a scale of meters. Empirical orthogonal function analyses (EOF)—a method analogous to principal components analysis which finds spatial patterns of variability and their time variation period—were used to define both the spatial and temporal variation in SGD using spatially resolved time series of salinity. The first two EOFs represented variability at the tidal 12‐h period and the daily 24‐h period, respectively, and were responsible for more than 50% of the SGD‐derived salinity variability. We used the first two EOFs to explore spatiotemporally explicit patterns in SGD variability and their relationships with benthic community structure in reef systems. Distance‐based linear models found significant relationships between multivariate community structure and variability in SGD at different periods. Taxa‐specific logistic regressions showed that zoanthids and turf are more likely to be present in areas with high tidally driven SGD variability, while the inverse relationship is true for the invasive rhodophyteAcanthophora spicifera, calcifying macroalgae, the native rhodophytePterocladiellasp., the cyanobacteriaLyngbyasp., and the invasive chlorophyteAvrainvillea amadelpha. These results show that benthic communities vary with respect to SGD derived salinity at the scale of hundreds of meters resulting in spatially heterogeneous biotic patches.