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Bycatch rates within the California halibut trawl fishery were calculated using landed catch data from 1997-2020 fishery logbooks and estimated using landed and discarded catches from 2002-2019 fishery observer data. Average bycatch rates were significantly different between the two datasets. The average bycatch ratio estimated from fishery logbooks was 0.36 [+ or -] 0.17 while the average bycatch ratio estimated from the observer data was 4.61 [+ or -] 1.29, based on the weight of bycatch to weight of California halibut catch. Additionally, the most frequently caught bycatch species were estimated for each dataset. Bycatch rates calculated from the observer data were closely aligned with fishery-independent surveys conducted by the California Department of Fish and Wildlife, signaling the importance of using fishery observers to obtain estimates of bycatch within the California halibut fishery. Spatial patterns of bycatch revealed that fishing effort was highest near Monterey, San Luis Obispo and Ventura. Our results suggest that data from logbooks alone are not sufficient to adequately estimate bycatch within the California halibut trawl fishery., In 2018, the California Fish and Game Commission adopted a new master plan for California fisheries. The new master plan, titled '2018 Master Plan for Fisheries, A Guide for Implementation [...]

Marine Protected Areas (MPAs) are being implemented worldwide, yet there are few cases where managers make specific predictions of the response of previously harvested populations to MPA implementation. Such predictions are needed to evaluate whether MPAs are working as expected, and if not, why. This evaluation is necessary to perform adaptive management, identifying whether and when adjustments to management might be necessary to achieve MPA goals. Using monitoring data and population models, we quantified expected responses of targeted species to MPA implementation and compared them to monitoring data. The model required two factors to explain observed responses in MPAs: (a) pre‐MPA harvest rates, which can vary at local spatial scales, and (b) recruitment variability before and after MPA establishment. Low recruitment years before MPA establishment in our study system drove deviations from expected equilibrium population size distributions and introduced an additional time lag to response detectability. Synthesis and applications. We combined monitoring data and population models to show how (a) harvest rates prior to Marine Protected Area (MPA) implementation, (b) variability in recruitment, and (c) initial population size structure determine whether a response to MPA establishment is detectable. Pre‐MPA harvest rates across MPAs plays a large role in MPA response detectability, demonstrating the importance of measuring this poorly known parameter. While an intuitive expectation is for response detectability to depend on recruitment variability and stochasticity in population trajectories after MPA establishment, we address the overlooked role of recruitment variability before MPA establishment, which alters the size structure at the time of MPA establishment. These factors provide MPA practitioners with reasons whether or not MPAs may lead to responses of targeted species. Our overall approach provides a framework for a critical step of adaptive management.

Integral projection models (IPMs) have a number of advantages over matrix-model approaches for analyzing size-structured population dynamics, because the latter require parameter estimates for each age or stage transition. However, IPMs still require appropriate data. Typically they are parameterized using individual-scale relationships between body size and demographic rates, but these are not always available. We present an alternative approach for estimating demographic parameters from time series of size-structured survey data using a Bayesian state-space IPM (SSIPM). By fitting an IPM in a state-space framework, we estimate unknown parameters and explicitly account for process and measurement error in a dataset to estimate the underlying process model dynamics. We tested our method by fitting SSIPMs to simulated data; the model fit the simulated size distributions well and estimated unknown demographic parameters accurately. We then illustrated our method using nine years of annual surveys of the density and size distribution of two fish species (blue rockfish, Sebastes mystinus, and gopher rockfish, S. carnatus) at seven kelp forest sites in California. The SSIPM produced reasonable fits to the data, and estimated fishing rates for both species that were higher than our Bayesian prior estimates based on coast-wide stock assessment estimates of harvest. That improvement reinforces the value of being able to estimate demographic parameters from local-scale monitoring data. We highlight a number of key decision points in SSIPM development (e.g., open vs. closed demography, number of particles in the state-space filter) so that users can apply the method to their own datasets.

Climate change and anthropogenic stressors affect the distribution, abundance, and diversity of fish communities across the world. To understand rapidly changing biotic communities, resource managers need a method to quickly and efficiently document temporal and spatial changes in community assemblages across various spatial scales. In this study, we describe the use of new video lander tools to survey fish communities in rocky marine habitats on the continental shelf and slope in California, USA. We evaluate how fish diversity metrics determined by video surveys vary among geographically distinct areas. Our results demonstrate that species diversity, evenness, and richness vary spatially across the coast. Furthermore, community assemblages differ at both broad and fine spatial scales because of differences among habitats. Length frequencies and densities of species in this study were similar to those reported in previous studies. As community assemblages and biodiversity metrics shift in response to changing stressors, it is increasingly important to develop tools and methodologies to detect and rapidly monitor these changes. [ABSTRACT FROM AUTHOR]

Globally, small-scale fisheries are influenced by dynamic climate, governance, and market drivers, which present social and ecological challenges and opportunities. It is difficult to manage fisheries adaptively for fluctuating drivers, except to allow participants to shift effort among multiple fisheries. Adapting to changing conditions allows small-scale fishery participants to survive economic and environmental disturbances and benefit from optimal conditions. This study explores the relative influence of large-scale drivers on shifts in effort and outcomes among three closely linked fisheries in Monterey Bay since the Magnuson-Stevens Fisheries Conservation and Management Act of 1976. In this region, Pacific sardine (Sardinops sagax), northern anchovy (Engraulis mordax), and market squid (Loligo opalescens) fisheries comprise a tightly linked system where shifting focus among fisheries is a key element to adaptive capacity and reduced social and ecological vulnerability. Using a cluster analysis of landings, we identify four modes from 1974 to 2012 that are dominated (i.e., a given species accounting for the plurality of landings) by squid, sardine, anchovy, or lack any dominance, and seven points of transition among these periods. This approach enables us to determine which drivers are associated with each mode and each transition. Overall, we show that market and climate drivers are predominantly attributed to dominance transitions. Model selection of external drivers indicates that governance phases, reflected as perceived abundance, dictate long-term outcomes. Our findings suggest that globally, small-scale fishery managers should consider enabling shifts in effort among fisheries and retaining existing flexibility, as adaptive capacity is a critical determinant for social and ecological resilience.

Collaborative fisheries research programs engage stakeholders in data collection efforts, often with the benefit of increasing transparency about the status and management of natural resources. These programs are particularly important in marine systems, where management of recreational and commercial fisheries have historically been contentious. One such program is the California Collaborative Fisheries Research Program (CCFRP), which was designed in 2006 to engage recreational anglers in the scientific process and evaluate the efficacy of California's network of marine protected areas. CCFRP began on the Central Coast of California and expanded statewide in 2017 to include six partner institutions in three regions: Northern, Central, and Southern California. To date, over 2,000 volunteer anglers have participated in the program, with many anglers volunteering for multiple years. However, the impacts of outreach, education, and collaborative research on those anglers at the statewide scale are currently unknown. Thus, the objective of the current study was to survey the statewide pool of volunteer anglers to assess the degree to which participation in CCFRP has influenced angler perceptions of MPAs, fisheries management, and conservation. We received 259 completed surveys out of a pool of 1,386 active anglers, equating to an 18.7% response rate. Participation in CCFRP resulted in a significant, positive impact on anglers' attitudes towards MPAs in California across all regions. Anglers who participated in six or more CCFRP fishing trips had a more positive perception of MPAs than those who participated in fewer trips. Volunteer anglers across all regions perceived that they caught larger fishes, a higher abundance of fishes, and a greater diversity of species inside MPAs, consistent with the ecological findings of the program. These results highlight the benefits of involving community members in collaborative scientific research. Collaboration between researchers and the broader community increases transparency and trust between stakeholders, and results in greater understanding of natural resource dynamics, ultimately producing better management outcomes. [ABSTRACT FROM AUTHOR]

The California Collaborative Fisheries Research Program, a partnership of fishermen, non-governmental organizations, and agency and academic scientists, developed protocols for monitoring marine protected areas in central California using hook-and-line and trap fishing gear. In the summer and fall of 2007, 2008, and 2009 the protocols were used to collect information about species composition, catch rates, and sizes of nearshore fishes in the Año Nuevo, Point Lobos, Piedras Blancas, and Point Buchon State Marine Reserves, and corresponding co-located reference sites. A total of 115 surveys, employing hook-and-line methods, were conducted from 2007 – 2009; 47 in the fall of 2007, 48 in the summer and fall of 2008, and 24 in the summer and fall of 2009, in and near the Año Nuevo, Point Lobos, Piedras Blancas and Point Buchon marine protected areas. A total of 68 trap fishing surveys occurred in and near the Año Nuevo, Point Lobos, Cambria, and Piedras Blancas marine protected areas; 43 in 2008 and 25 in 2009. During these surveys, all caught fishes were identified, measured, tagged with external T-bar anchor tags, and released at location of capture. A total of 12 Commercial Passenger Fishing Vessels, 4 commercial trap-fishing vessels, and 415 volunteer anglers spent a total of 1,121 hours fishing with hook-and-line gear, and 3,445 hours fishing with trap gear. This combined effort resulted in a total catch of 26,262 fishes, which were comprised of 42 species. Of the total catch 22,551 fishes were tagged and released. Out of the fishes released with tags, 119 were recaptured and reported to our offices with information about the location of recapture. The ten most frequently caught species were similar among marine protected areas, and the composition between paired marine protected areas and reference sites is more similar than among marine protected areas, indicating that the reference sites chosen are well-suited for comparisons with associated marine protected areas. Catch and biomass rates for most species were higher in marine protected areas than in reference sites, indicating habitat differences existed prior to the establishment of the MPAs. When differences in mean lengths of fishes were detected, the lengths were most often greater in marine protected areas than in associated reference sites.

In September 2009 we surveyed the deep habitats and fish assemblages of Las Gemelas seamounts and Parque Nacional Isla del Coco, as part of the National Geographic expedition. We conducted four submarine dives at the Las Gemelas seamounts and 18 dives around Isla del Coco, using a combination of quantitative video transects and general observations to characterize fish communities at each study site. We surveyed habitats in depths ranging from 50 – 402 m, but are reporting only the data obtained from dives in rocky habitats that were deeper than 150 m, to facilitate a comparison of deepwater communities at Las Gemelas seamounts and Isla del Coco.

University of California Sea Grant Extension Program and the California Department of Fish and Game (CDFG) convened a fisheries management workshop December 1-4, 2008, in Berkeley, CA. The workshop, entitled “Managing Data-Poor Fisheries: Case Studies, Models and Solutions,” was designed to provide ideas to CDFG about ways to manage California fisheries when available data are insufficient for single species or ecosystem-based management.

The prickly shark Echinorhinus cookei is a poorly known predatory shark that occurs in the Monterey Canyon, USA. Between March 2005 and September 2006, 15 subadult prickly sharks (170 to 270 cm total length) were tagged with acoustic transmitters and tracked to determine their site fidelity, home range, habitat use, rates of movement, and diel activity. An array of moored receivers extending 3.5 km offshore from the apex of the Monterey Canyon recorded the occurrence of 8 sharks tagged with coded transmitters for 400 to 561 d. Four sharks were tagged with continuous transmitters and monitored by a moored receiver that recorded date, time, and depth for 123 to 212 d. Three sharks were tagged with archival transmitters that were monitored by a 2-way communicating moored receiver. One female and 2 males tagged with continuous transmitters were also tracked manually from a surface vessel for 61.0, 51.8 and 62.8 h, respectively, over a period of 64 to 71 d. Home ranges for these sharks were 0.20, 2.20, and 1.46 km2. All tagged sharks showed a high degree of site fidelity to the study area and demonstrated pronounced diel movements, moving along the axis of the canyon offshore to discrete areas during the day and inshore at night. Sharks were sedentary during the day and actively swam in the water column at night and were most active during crepuscular and nighttime periods.

Abstract--In August and September of 1997 and 1998, we used SCUBA techniques to surgically implant Vemco V16 series acoustic transmitters in 6 greenspotted rockfish (Sebastes chlorostictus) and 16 bocaccio (S. [...]