California Department of Fish and Wildlife

Trapping and Mark-Recapture of Nearshore Fishes in Carmel Bay

Updated June 30, 2011

Background

Project logo

The sustainable management of marine fisheries requires basic information about the biology and harvest of fish species. This may include information on life history (e.g. age, growth, and reproduction), habitat requirements, and fishery trends. Collectively, this body of biological, ecological, and socioeconomic information is known as essential fishery information (EFI), which is used in the development of fishery management plans (FMPs).

Under the Marine Life Management Act, the CDFW is required to create FMPs that will form the primary basis for managing California's marine fisheries. Kelp greenling (Hexagrammos decagrammus) and cabezon (Scorpaenichthys marmoratus) are two of the 19 finfish species in the CDFW's Nearshore Fishery Management Plan. Both species inhabit nearshore kelp beds and rocky reefs, and are highly sought after by both recreational and commercial fishermen. Recent reviews in California have listed these species, as well as several other nearshore species, as lacking EFI. Current knowledge on kelp greenling and cabezon population biology is limited, especially regarding abundance and mortality.

Study Methods

T-bar anchor tag in cabezon, CDFW photo by Diane Haas
T-bar anchor tag in cabezon

Tagging a black-and-yellow rockfish, CDFW photo by Diane Haas
Tagging a black-and-yellow rockfish

Black-and-yellow rockfish recently recaptured after 267 days at liberty, CDFW photo by Diane Haas
Black-and-yellow rockfish recently
recaptured after 267 days at liberty

From 2008 to 2010, a trapping study was conducted to capture, tag, and recapture fishes to collect missing EFI for kelp greenling, cabezon, and other important nearshore fishes at two sites around Carmel Bay. These sites were located in both fished and protected areas. Information collected includes species composition, catch per unit of effort (CPUE), size, and movement of nearshore groundfishes. This study will augment data used by other projects and will be valuable for management and future stock assessments.

Fish trapping:

Two sites were sampled: Lingcod Reef off of Pescadero Point and Point Lobos State Marine Reserve (SMR). Traps were deployed each year during summer months, typically July through September. Each site consisted of four 250 x 500 m grid cells.

At each site, grid cells were randomly selected to sample over a three day period. In each selected grid cell, three sets of 12-15 traps were deployed daily. One set was attempted in each of three depths per day: less than 30 ft., 31-60 ft., and 61-90 ft. Each trap was baited with chopped squid, deployed 10 to 20 meters apart, and soaked for about one hour. Captured fish were measured, weighed, tagged, and released.

Findings to Date

Catch and effort

  • 2,272 traps deployed over 60 days of sampling
  • 1,673 fish from 16 species captured and tagged
  • Average CPUE = 0.73 fish/trap hour
    • Overall, CPUE was greater at Point Lobos (0.76 fish/trap hour) than at Lingcod Reef (0.70 fish/trap hour)
  • The most abundant species caught were:
    • Gopher rockfish (Sebastes carnatus)
    • Black-and-yellow rockfish (Sebastes chrysomelas)
    • Kelp greenling
    • Cabezon
  • A wide size-range of fish were caught:
    • Smallest: 124 mm TL striped surfperch (Embiotoca lateralis)
    • Largest: 1,150 mm TL wolf-eel (Anarrichthys ocellatus)

Effects of sites and depths

  • CPUE varied by site, depth, and species
    • Gopher rockfish had greater CPUE at Point Lobos SMR
    • Cabezon had greater CPUE at Lingcod Reef
  • Fish were larger at Point Lobos, particularly black-and-yellow and gopher rockfish
  • More species were captured at Lingcod Reef than at Point Lobos SMR each year
  • In all years combined, 16 species were found at Lingcod Reef while 11 species were found at Point Lobos SMR.

Catch per unit effort (CPUE) for the six of the most abundant species by site
Catch per unit effort (CPUE) for four of the most abundant species by site and year.

Recaptures

  • To date, 46 fish have been recaptured (~3% recapture rate)
  • Recapture species include black-and-yellow rockfish, gopher rockfish, cabezon, kelp greenling, and lingcod
  • Fish made gross movements of 3 to 270 m from tagging site
  • Fish were recaptured from 22 to 1,014 days after original capture
  • Nine tagged fish have been re-sighted during scuba surveys

Map of Carmel Bay showing grid cells at Lingcod Reef and Point Lobos sampling sites
Map of Carmel Bay showing grid cells at Lingcod Reef and Point Lobos SMR sampling sites.
Recaptured fish start and end points are shown in green.


Overall, trapping efforts were successful in collecting cabezon, greenling, and other nearshore species of interest. The species composition, CPUE and recapture rate of fishes collected during this study were comparable to those found in other nearshore trap studies. The information collected during this study will provide a basis of comparison for future studies. Stay tuned for more information!

What to do if you catch a tagged fish

Each tag has a unique ID number and a CDFW phone number for anglers to call when they catch a tagged fish. Anglers are asked to provide the following information when reporting a tagged fish:

  • tag number
  • date caught
  • general location or GPS coordinates
  • total length (estimated or measured)
  • any additional information