Mark and Recapture Studies of Nearshore Groundfishes in the Carmel Bay Area
- Scot Lucas
California Department of Fish and Wildlife
- Chuck Valle
California Department of Fish and Wildlife
This project consists of two components that are part of a broader project to collect information to support fisheries management and baseline information for the purpose of evaluating marine protected area (MPA) efficacy for marine resources in the Monterey Bay region. This project provides critical information on nearshore groundfish populations, movement, and species composition in the Carmel Bay region. A focal area for this project is the Carmel Pinnacles State Marine Reserve, which was implemented in September 2007. Since then coordinated efforts to collect baseline information have been ongoing. Data are being collected within the MPA and at fished reference sites outside the MPA to track changes in community structure and to inform fishery management on the status of populations following spatial and temporal fishery restrictions.
This project supports two very different methods to collect fishery-related data. The goal is to provide two independent data sets: 1) the mark and recapture component provides information on population size, catch rates, species composition including individual size, and movement while 2) the diving portion provides information on community structure and species composition, abundance, and information on the health of fish after tagging.
Summary to DateThe following findings are preliminary and based on data collected in 2008.
A total of 72 anglers using hook-and-line gear caught 1833 fish, more than 1400 of which were tagged aboard the vessel and released on site (Table 2). More fishes were caught outside the MPA than were caught inside; canary, black, vermilion, olive, and yellowtail rockfish were much more abundant at Carmel Point. Blue, gopher and olive rockfish were the most common fishes caught both inside and outside of the MPA.
471 fishes were caught using trap gear and over 450 of these were tagged on the vessel and subsequently released (Table 1). Using trap gear, more fishes were caught inside the MPA than outside; gopher rockfish, china rockfish, and cabezon were more abundant at the Carmel Pinnacles SMR. Gopher rockfish was the most common fish caught at both sites.
Most fishes caught by hook-and-line fishing inside the MPA were similar in size to those caught outside the MPA. However, blue rockfish, olive rockfish, and kelp greenling were moderately larger at the Carmel Pinnacles SMR whereas lingcod and copper rockfish were moderately larger at the non-protected Carmel Point site (Table 3). Fishes caught by trapping were similar in size inside and outside the SMR; however, black-and-yellow rockfish were moderately larger at the SMR (Table 4).
As of January 1, 2009, 13 tagged fish have been recaptured and released by us on our sampling days; 6 tagged fish have been recaptured by the public (recreational skiff fishermen); and 5 tagged fish have been visually recaptured by our efforts using SCUBA gear on 4 dives (Table 5).
DiscussionFor the near future, this study should be repeated annually during the same months for three consecutive years (at a minimum). This is funding dependent. In the long-term, surveys should be repeated periodically (e.g., every 2nd or 3rd year) to track temporal trends and evaluate whether the fish community has changed over time.
- Size structure
- Migration/movement patterns
Study MethodsA commercial passenger fishing vessel was used as a platform to hook-and-line catch and tag fishes at Pinnacles and a nearby reference site, Carmel Point (Figure 1). Fishing occurred within two 500m x 500m grid cells at each site. Three 15-minute drifts were fished in each of the four grid cells each sampling day for nine days from July-September 2008. To utilize local fishing knowledge of the Carmel Bay area, locations of each drift within a grid cell were determined by the skipper and fished by 6-12 anglers. Three gear types were used equally to catch fish: shrimp flies, shrimp flies with bait, and bar jigs with a shrimp fly teaser. To reduce mortality, fishing was limited to depths less than 120 feet; similar depths were fished both inside the MPA and at the reference site. Following capture, fish were measured, tagged and released. Fish exhibiting excessive trauma or fish that were less than 20 cm total length were not tagged. Flyers posted at boat ramps, tackle shops and online, were used to recruit experienced volunteer anglers to catch fish for the study.
Trapping complemented the hook-and-line component of this study to aid in catching certain fish that are more effectively sampled using trap gear. Trapping occurred within the same grid cells as above, but during different weeks than the hook-and-line fishing. Two sets of 10 traps (24”X 24”X10”) each were fished in each of the four grid cells during 8 days from August-October 2008. One pint of squid was used as bait and set in a smaller cage in the center of the trap. Traps were pulled after soaking for about one hour. To reduce mortality and facilitate trap retrieval, trapping was limited to depths less than 75 feet; similar depths were fished both inside the MPA and at the reference site. Following capture, fish were measured, tagged and released.
Species of interest include: cabezon (Scorpaenicthys marmoratus), kelp greenling (Hexagrammos decagrammus), lingcod (Ophiodon elongatus), black rockfish (Sebastes melanops), black-and-yellow rockfish (S. chrysomelas), blue rockfish (S. mystinus), bocaccio rockfish (S. paucispinis), brown rockfish (S. auriculatus), canary rockfish (S. pinniger), china rockfish (S. nebulosus), copper rockfish (S. caurinus), gopher rockfish (S. carnatus), grass rockfish (S. rastrelliger), kelp rockfish (S. atrovirens), olive rockfish (S. serranoides), treefish (S. serriceps), vermilion rockfish (S. miniatus) and yellowtail rockfish (S. flavidus).
Figures and Images
Figure 1. Location of sampling sites at Carmel Pinnacles State Marine Reserve (SMR) and the Carmel Point reference area.
Table 1. Number of fishes caught using trapping gear in 2008.
Table 2. Number of fishes caught at both sites using hook-and-line gear in 2008.
Table 3. Minimum, maximum and average total length of fishes caught using hook-and-line gear in 2008.
Table 4. Minimum, maximum and average total length (cm) of fishes caught using trap gear in 2008.
Table 5. Recaptures of tagged fishes by method in 2008.