A network of marine protected areas (MPAs) has recently been established off the coast of southern California. In order to monitor species within these reserves, it is necessary to assess the current state of populations. A baseline for monitoring fish spawning within two of these MPAs was established from 2012 to 2013 using a standardized vertical plankton net tow to collect fish eggs off the pier at Scripps Institution of Oceanography multiple times per week. Molecular methods were used to identify eggs, allowing for more accurate identification than the more commonly used morphological methods. The mitochondrial COI or 16S gene was amplified from extracted DNA, and sequences were compared to DNA barcode databases. A total of 8588 eggs and 38 different species of fish were identified, including commercially and recreationally important species such as Engraulis mordax (Northern anchovy), Sardinops sagax (Pacific sardine), and Semicossyphus pulcher (CA sheephead). Species that are uncommon in this region, including Cynoscion parvipinnis (shortfin weakfish) and Citharichthys gordae (mimic sanddab), were observed, which may be indicative of ongoing range shifts in breeding habitat. Permutational multivariate analysis of variance (PERMANOVA) was used to test for differences in species assemblages between months. Using a likelihood ratio test, spawning was found to be significantly correlated with sea surface temperature for many species. This survey can allow future studies to monitor changes in spawning activities over time

In order to protect the diverse ecosystems of coastal California, a series of marine protected areas (MPAs) have been established. The ability of these MPAs to preserve and potentially enhance marine resources can only be assessed if these habitats are monitored through time. This study establishes a baseline for monitoring the spawning activity of fish in the MPAs adjacent to Scripps Institution of Oceanography (La Jolla, CA, USA) by sampling fish eggs from the plankton. Using vertical plankton net tows, 266 collections were made from the Scripps Pier between 23 August 2012 and 28 August 2014; a total of 21,269 eggs were obtained. Eggs were identified using DNA barcoding: the COI or 16S rRNA gene was amplified from individual eggs and sequenced. All eggs that were successfully sequenced could be identified from a database of molecular barcodes of California fish species, resulting in species-level identification of 13,249 eggs. Additionally, a surface transport model of coastal circulation driven by current maps from high frequency radar was used to construct probability maps that estimate spawning locations that gave rise to the collected eggs. These maps indicated that currents usually come from the north but water parcels tend to be retained within the MPA; eggs sampled at the Scripps Pier have a high probability of having been spawned within the MPA. The surface transport model also suggests that although larvae have a high probability of being retained within the MPA, there is also significant spillover into nearby areas outside the MPA. This study provides an important baseline for addressing the extent to which spawning patterns of coastal California species may be affected by future changes in the ocean environment.