California Collaborative Fisheries Research Project: Surveys of Nearshore Fishes in and near Central California Marine Protected Areas
- Richard Starr
California Sea Grant
- Dean Wendt
California Polytechnic State University, San Luis Obispo
California's Central Coast Marine Protected Areas (MPAs) took effect Sept. 21, 2007. From Pigeon Point (San Mateo County) south to Point Conception (Santa Barbara County), the series of 29 marine protected areas represent approximately 204 square miles (or approximately 18 percent) of state waters (intertidal to 3 nautical miles offshore) in the Central Coast Study Region. The 29 sites include:
This new network effectively launches the Marine Life Protection Act Program, which was designed to better conserve marine resources for their long-term sustainable use while also enhancing outdoor recreation and ocean research opportunities along the coast.
We worked with the fishing communities of Half Moon Bay, Monterey Bay, Morro Bay, and Port San Luis, California to develop monitoring protocols for the use of hook and line fishing gear, and to collect baseline information for three Marine Protected Areas that were established in September 2007. We completed a total of 34 fishing trips in the Fall of 2007 in the Año Nuevo, Point Lobos, and Point Buchon State Marine Reserves, and in corresponding reference sites. Within these areas, we used a stratified random sampling design to determine sampling locations. At each location, experienced volunteer anglers fished with standardized gear for a specified amount of time. We worked with a total of five Commercial Passenger Fishing Vessels (CPFV) and 174 volunteer anglers, and caught a total of 7,928 fishes, comprised of 27 species. Caught fishes were identified, measured, tagged with external T-bar anchor tags, and released at location of capture.
Summary to DateOn September 21, 2007, 29 Marine Protected Areas (MPAs) were established along the central California coast from Pigeon Point to Point Conception. The 1999 Marine Life Protection Act that led to the formation of the new MPAs specifically required California MPAs to be monitored and evaluated. As part of 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 winter of 2006 and spring of 2007, we conducted a series of five workshops with fisheries scientists and the fishing communities of Half Moon Bay, Monterey, Morro Bay, and Port San Luis, California to develop protocols for monitoring MPAs using hook-and-line fishing gear. Since 2007, we have used the protocols developed at the workshops to collect information every summer about species composition, catch rates, and sizes of nearshore fishes in the Año Nuevo, Point Lobos, Piedras Blancas, and Point Buchon State Marine Reserves (MPAs; Figure 1), and corresponding reference (REF) sites. In 2008, we conducted additional workshops with members of the live-fish fishery to develop protocols for monitoring MPAs using trap fishing gear. Trap fishing protocols were used in 2008 and 2009 to assess the Año Nuevo, Point Lobos, Piedras Blancas, and Cambria MPAs and REF sites (Figure 2). Specific sampling protocols and terminologies are described in more detail at the California Collaborative Fisheries Research Program web site.
In the summer and fall from 2007 – 2011, 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. In our five years of sampling, a total of 179 days of fishing surveys, employing hook-and-line methods, were conducted across central California. Additionally, 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 16 Commercial Passenger Fishing Vessels, 4 commercial trap-fishing vessels, and more than 500 volunteer anglers spent a total of 4,855 hours fishing with hook-and-line gear, and 3,445 hours fishing with trap gear. This combined effort resulted in a total catch of 32,858 fishes, which were comprised of 42 species. Of the total catch, 26,721 fishes were tagged and released. To date, 335 tagged fishes were recaptured and reported to our offices with information about the length of the fish at the time of capture and location of recapture. The thirteen most frequently caught species were similar among marine protected areas (Figure 3). 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 (Figure 4). 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 (Figure 5). When differences in mean lengths of fishes were detected, the lengths were most often greater in marine protected areas than in associated reference sites.
During the course of this study, 27 different species of fishes from 10 genera were caught. The majority (97%) of the caught fishes were rockfishes, from the Genus Sebastes. For all areas combined, blue rockfish were the most frequently caught (38% of the total catch), followed by gopher rockfish (27%), black rockfish (11%), and olive rockfish (10%). The Shannon diversity index (H) value was 1.80 for all areas and sites combined and for the individual sites values ranged from 1.35 to 1.82.
Total lengths (measured to the nearest cm) of caught fishes ranged from 8 – 87 cm. Of the ten most frequently caught species (those species that were greater than or equal to 1.5% of the total catch in any area), mean lengths of six species were significantly different (p<0.05) among areas. Mean lengths of the fishes in Point Lobos (all sites combined) were larger than both of the other areas, with the exception of gopher rockfish, which were largest in Año Nuevo. Average lengths of these species also showed variation between the MPA and reference sites.
A two-sample t-test indicated that mean lengths of black, blue, and yellowtail rockfish at Año Nuevo were significantly larger (p < 0.001) in the MPA than in the reference site, and vermilion rockfish were significantly larger (p < 0.05) in the reference site.
A two-sample t-test indicated that mean lengths of black, copper, kelp, and vermilion rockfish at Point Lobos were significantly larger (p < 0.05) in the MPA than in the reference site, as were blue and china rockfish (p < 0.001).
A two-sample t-test indicated that mean lengths of lingcod and vermilion rockfish at Point Buchon were significantly (p < 0.05) larger in the MPA than in the reference site; olive rockfish also were significantly (p < 0.001) larger in the reference site.
Catch rates are reported as the average catch per angler hour and were calculated by dividing the total number of fishes caught by the total number of angler hours fished in a grid cell in a day. Catch rates varied among areas and sites. The highest catch per angler hour was in the Point Lobos MPA (19.2 total fish per angler hour) and the lowest was in the Año Nuevo MPA (4.3 total fish per angler hour). Within each site, catch rates also varied by species. The highest overall catch per angler hour values were for black, blue, gopher, and olive rockfishes.
Comparisons with Other Data:
We compared catches from the trips completed in Año Nuevo to CPFV (Commercial Passenger Fishing Vessel) landings on the same day from the same general area. The catches were similar in species composition and abundance, indicating that our survey is representative of what is being caught by other recreational anglers. Likewise, for Point Buchon, catch rates, sizes, and species composition were similar to that reported by Stephens et al. (2006) in their analysis of catch on CPFVs for the south central coast from 1988-2006.
For several species, we compared average fish lengths from this study to historic average lengths of fishes caught near our study areas. These values were obtained by compiling unpublished California Department of Fish and Game onboard central California CPFV observer data from 1987 to 1998 (Data courtesy of Deborah Wilson-Vandenberg). For most species that were evaluated, the average lengths from this study fell within the range of historic values.
Año Nuevo MPA + Reference Site
August 12, 13, 14, 15
1,677 fishes from 19 species
September 23, 24, 25, 26
2,028 fishes from 16 species
Point Lobos MPA + Reference Site
August 19, 20, 26, 27
877 fishes from 17 species
September 9, 10, 16, 17
542 fishes from 18 species
Piedras Blancas MPA + Reference Site
July 15, 16, 29, 30
622 fishes from 19 species
August 19, 20, September 3, 4
718 fishes from 16 species
DiscussionThe California Resources Agency and California Department of Fish and Game have partnered with the Resources Legacy Fund Foundation in an initiative to achieve the goals of the 1999 Marine Life Protection Act (MLPA). The MLPA directs the state to design and manage a network of marine protected areas in order to, among other things, protect marine life and habitats, marine ecosystems, and marine natural heritage, as well as improve recreational, educational and study opportunities provided by marine ecosystems. Scientists, resource managers, experts, stakeholders and members of the public all play important roles in guiding the outcomes of this public-private partnership. Marine protected areas include state marine reserves, state marine parks and state marine conservation areas.
Implementation of the act will occur in five study regions, in the following order:
- Size structure
- Age structure
- Migration/movement patterns
- Habitat association
During the planning phase of this project, a series of five workshops were held in Morro Bay, Moss Landing, and Santa Cruz, California to obtain ideas about protocols for this study from the fishing, science, and management communities. During the later workshops, boat captains used their experience and knowledge to assist us in choosing sampling locations. Additional workshops were held after the field sampling season in Morro Bay, Moss Landing, and Half Moon Bay, at which members from these communities offered suggestions on how to improve upon this project.
Sampling Locations and Nomenclature:
The Año Nuevo, Point Lobos, and Point Buchon State Marine Reserves (SMR) were chosen as sampling locations for this study because the nearshore rocky habitat within the selected MPAs is extensive and representative of the rocky habitat in the central California coastal region, and the sites have long been popular fishing areas for both recreational and commercial fishermen. The Año Nuevo, Point Lobos, and Point Buchon SMRs encompass areas of 10.2, 5.4, and 6.7 square miles, respectively. Reference sites were based on the criteria that they shared similar size, habitat, and oceanographic conditions with the nearby MPAs.
Within each MPA and reference site, 500 m x 500 m grid cells were created and used to delineate sampling locations. A total of 22 grid cells in Año Nuevo, 18 in Point Lobos, and 22 in Point Buchon were generated, with equal numbers of grid cells located in both the MPA and reference sites. The grid cells were positioned in nearshore rocky habitats, in water less than 40 meters deep (to limit fishing mortality from barotrauma), and in areas that had previously been identified by fishermen as having suitable habitat for nearshore fishes.
In each area, we sampled four days a month in August, September, and October (a total of 12 days in each area) to account for temporal variability in fishing conditions and fish distribution. Half of the fishing days were spent in the Marine Protected Area (MPA) sites and the other half in the reference sites. During each day of sampling, four of the grid cells (in a given MPA or reference site) were chosen at random and sampled. In the morning, the captain was provided with the coordinates of the sampling cell and asked to fish in each cell in locations where he thought he could best catch fish. A total sampling time of 1½ hr was allotted for each grid cell. In order to account for the variability within each cell, the captain was instructed to locate three suitable fishing locations within each grid cell and complete a fishing drift in each for 15 minutes. If a single 15-minute drift was not possible, due to strong currents or other reasons, the captain could choose to make several drifts in the same location for a combined total of 10-15 minutes. The objective was to fish in three discrete locations within the grid cell for a total of at least 30 minutes, but no more than 45 minutes.
We recruited volunteer anglers to fish in this study. Anglers were recruited from various fishing clubs, online fishing websites, and from previous collaborative studies. Some anglers volunteered after they heard of the project through local media. We required that all volunteer anglers were experienced with rockfish fishing, over the age of 16, and capable of fishing consistently for six hours.
At the beginning of the trip, each angler was assigned to a fishing station, which was organized by gear type. Once on station, the captain signaled the start of the drift, and the anglers would commence fishing using standardized gear for a measured amount of time.
When a fish was caught, it was identified to species, measured (total length), tagged with an external T-bar anchor tag (unless the fish was in poor condition or was too small), and released. The location (latitude and longitude) and depth where a fish was released were recorded. In order to reduce incidental mortality, care was taken when handling the fishes, and the duration of time that the fishes were on board the vessel was minimized. If a high catch rate precluded rapid processing of the captured fishes, anglers were instructed to stop fishing so that the fish on board could be processed and the number of anglers was reduced before fishing recommenced. If a fish exhibited signs of barotrauma, its swim bladder was vented with a hypodermic needle and/or was released at depth with a fish-descending device (either the Ace Calloway Barotrauma Reversing Fish Release or a weighted milk crate). All caught fishes were released after processing, except for a small sub-sample of gopher rockfish, which were retained for a diet study.
At each grid cell that was sampled in Año Nuevo and Point Lobos, we measured water temperature at depth using a sensor that continuously recorded temperature and pressure readings. Water clarity was measured with a secchi disc in each cell. Also, during each drift we recorded surface water temperature, observations on the weather, wind speed and direction, swell height and direction, presence of harbor seals and/or seal lions and/or kelp beds, and, if possible, current direction and speed and amount of relief.
Two websites were created for this project, one through a San Luis Obispo Science and Ecosystem Alliance domain (http://www.slosea.org/collaborative) and one through a Moss Landing Marine Laboratories, domain (http://seagrant.mlml.calstate.edu/crmpamonitor.php). Information about this study is posted on these websites. The websites contain a project overview, background information, a description of the study areas (including maps), sampling results, volunteer sign up information, media related to the project, and information on what to do with a recaptured tagged fish. In addition, information about the project was posted periodically on well-known fishing websites.
Posters illustrating a tagged rockfish, with a summary of the objectives of this study, and an explanation of how and where to report a tagged rockfish were disseminated to all of the volunteer anglers, to local fishing websites, on the websites for this project, and were placed in key fishing areas along the central coast. These posters spread awareness about the project and will increase tag returns and participation in further collaborative projects.
Figures and Images
Figure 1. Marine Protected Areas (MPAs) evaluated using CCFRP’s hook-and-line surveys.
Figure 2. MPAs evaluated using CCFRP’s trapping surveys.
Figure 3. A total of 13 species accounted for 98% of the fishes caught in CCFRP surveys and their relative abundance varies by area.
Figure 4. Spatial analyses of MPA and REF (reference) pairs indicate that the species composition in a MPA and its REF pair is more similar than among MPAs in different areas, indicating that the reference sites were well chosen.
Figure 5. Total BPUE (biomass (kg) per angler hour) for the MPA and REF, all species combined (2007-2010) for the sites of (a) Año Nuevo; (b)Point Lobos; (c) Piedras Blancas; and (d) Point Buchon.
Figure 6. Average total lengths (cm, with standard error bars) for the ten most frequently caught species by site (Marine Protected Area (MPA) and Reference (REF)) in a) Año Nuevo (AN), b) Point Lobos (PL), and c) Point Buchon (PB). Significant differences between sites were determined using a two-sample t-test. Significance is indicated with asterisks (*).
Figure 7. A brown rockfish (Sebastes auriculatus), recently caught by a volunteer angler. The captain and deckhand of the boat are also pictured.
Figure 8. Moss Landing Marine Lab Researcher Noëlle Yochum tagging a lingcod (Ophiodon elongatus) prior to releasing it back into the ocean.
Figure 9. Volunteer anglers fish, while Moss Landing Marine Lab Researcher Kristin Hunter-Thomson tags and releases fishes.
Figure 10. A tagged vermilion rockfish (Sebastes miniatus) on the measuring board.
Figure 11. The F/V Huli Cat, one of the Commercial Passenger Fishing Vessels (CPFVs) on which the surveys were conducted.
Figure 12. A tagged black rockfish (Sebastes melanops) just before being released back into the water.