Halfmoon/Blue Perch

The Science

They have a dark spot over the gill that may serve as a ‘fake eye’ to distract or confuse predators [15]

The Fishery

Will attach to anything it thinks is food, even if the item doesn’t remotely look like food [13]

The Seafood

Easy to cook in many different ways, if you’re looking for a healthy alternative protein source, perch tastes great baked [18]

The Science

Sean Glumace, glumacefishing,com

Taxonomic description

  • Tail fin shape looks like a crescent moon, hence its name [17]
  • Body is oval and typically dark blue in color [9], dark spot just above gill opening [15], looks similar to opaleye [1]
  • Adults mature at around 20-34 cm (8-13 in.), but can reach up to 50 cm [2]
  • Scales are small, thick and rough [15]


  • Range from Gulf of California to Vancouver Island, British Columbia [9]

Life history

  • Typically lives from 1-8 years, 8 years old being the maximum known [15]
  • Sexually mature at about 2 years old, internal fertilization, spawns eggs during July to October [15]
  • Fertilized eggs and hatched larvae float in the water column as plankton [15]
  • Juveniles typically school together and are sometimes found mixed with pileperch schools of 15-50 members [15, 6]


  • Typically inhabits shallow rocky areas, kelp beds and floating kelp paddies [9]
  • Common predators include sea lions, larger fish, and, specifically at the Santa Catalina Island, Bald Eagles [15]
  • Susceptible to disturbances that influence its kelp forest home, like habitat degradation and pollution [4]

The Fishery

Ken Jones

Seasonal availability

  • Available from August to April [18]

Managing authority

  • NOAA Fisheries and Pacific Fisheries Management Council under the Federal Groundfish Fisheries Management Plan, within which this species is incidentally caught [11]
  • California Department of Fish and Wildlife, may also fall under the State’s Nearshore Fisheries Management Plan as incidental catch [8]

Gear type

  • Mostly hook and line, with some Incidental catch in traps [18] and round haul nets [8]
  • Bait and tackle, prefers mussels or small crabs [7]

Status of the fishery

  • There are no regulations specific to this species; before 1976, catch of this species was grouped into the category of ‘surf perch,’  a more popular species, but now catch is reported separately [8]
  • Despite dips and peaks since 1970, there was overall decline in amount of halfmoon perch caught per year, with 0 pounds reported 1996-2002 [12] due to poor documentation, perch species were often unspecified [8]
  • IUCN Red List classifies halfmoon perch as “least concern” throughout its range [5]

Potential ecosystem impacts

  • According to a Productivity Susceptibility Analysis, low risk from being impacted by fishing activities [10]
  • No significant ecosystem impacts known.

The Seafood

Roz Corieri Paige, La Bella Vita Cocina

Edible portions

  • Can be eaten whole, scaled, and/or gutted [21]

Description of meat

  • Light, white, mild flavored meat, similar to surfperch [13, 7]

Culinary uses

  • Available fresh and whole [21]
  • Used as filets, with the skin on or off, or whole [19, 21]
  • Often baked, grilled, breaded and fried, or sautéed [19]
  • Prep instructions can be found at [3] and [21]

Nutritional information

  • One perch fillet is measured in the nutritional facts label [20]
  • Rich in omega-3 fats and Vitamin B12 [20]

Toxicity report

  • No toxins or dietary warnings [6]

Seasonal availability

  • Seasonal from August to April [18]


[1] Boerger, Christiana M. 2011. “Life History, Diet, and Production of an Herbivorous Temperate Marine Fish, Medialuna Californiensis (Fam. Kyphosidae).” California State University, Northridge. http://scholarworks.csun.edu/bitstream/handle/10211.2/824/Thesis.pdf?seq....

[2] Bredvik, Jessica J., Christiana Boerger, and Larry G. Allen. "Age and growth of two herbivorous, kelp forest fishes, the opaleye (Girella nigricans) and halfmoon (Medialuna californiensis)." Bulletin, Southern California Academy of Sciences 110, no. 1 (2011): 25-34.

[3] Croswell, Jonathan. 2015. “How to Cook Ocean Perch Fillets.” Web. http://www.livestrong.com/article/445749-how-to-cook-ocean-perch-fillets/.

[4] Fisheries, NOAA. 2017. “Threats to Kelp Forests: NOAA Fisheries.” Accessed May 28. http://www.westcoast.fisheries.noaa.gov/habitat/habitat_types/kelp_forest_info/kelp_forest_threats.html.

[5] International Union for Conservation of Nature and Natural Resources. 2000. The IUCN Red List of Threatened Species. IUCN Global Species Programme Red List Unit. http://www.iucnredlist.org/details/183618/0.

[6] Jones, Ken. 2014. “Pier Fish of Catalina Island.” Web. http://kenjonesfishing.com/2014/02/pier-fish-of-catalina-island/.

[7] Jones, Ken. 2017. “Halfmoon [Pier Fishing in California].” Web. Accessed May 28. http://www.pierfishing.com/resources/index.php?id=fish:halfmoon.

[8] Larinto, Traci (Editor). 2013. “STATUS OF THE FISHERIES REPORT AN UPDATE THROUGH 2011.” https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=65489&inline.

[9] Marine Region, California Department of Fish and Game, and Nancy Wright. 2002. “Nearshore Fishery Management Plan (NFMP).” Web. https://www.wildlife.ca.gov/Conservation/Marine/NFMP#27981664-list-of-ta

[10] Micheli, Fiorenza, Giulio De Leo, Cheryl Butner, Rebecca G. Martone, and Geoff Shester. "A risk-based framework for assessing the cumulative impact of multiple fisheries." Biological Conservation 176 (2014): 224-235.

[11] NOAA, Pacific Fishery Management Council. 2017. “PACIFIC COAST GROUNDFISH FISHERY MANAGEMENT PLAN FOR THE CALIFORNIA, OREGON, AND WASHINGTON GROUNDFISH FISHERY.” Web. http://www.pcouncil.org/wp-content/uploads/2017/03/GF_FMP_FinalThruA27-Aug2016.pdf.

[12] Simons, R.A. 2016. ERDDAP. https://coastwatch.pfeg.noaa.gov/erddap . Monterey, CA: NOAA/NMFS/SWFSC/ERD.

[13] Spira, Jeff. Saltwater Angler's Guide to Southern California. Wilderness Adventures Press, 2007.

[14] “California Marine Sportfish Identification: Other Fishes.” 2013. October 17. https://www.wildlife.ca.gov/Fishing/Ocean/Fish-ID/Sportfish/Other-Fishes#halfmoon.

[15] “Aquarium of the Pacific | Online Learning Center | Halfmoon.” 2017. http://www.aquariumofpacific.org/onlinelearningcenter/species/halfmoon

[17] “NOAA - Encyclopedia of the Sanctuaries.” 2017. Web. https://www8.nos.noaa.gov/onms/park/parks/SpeciesCard.aspx?pID=3&refID=2&CreatureID=85.

[18] “Tuna Harbor Dockside Market.” 2017. Web. http://thdocksidemarket.com/new/#species.

[19] “How Do You Cook Surf Perch?” 2017. Web. http://www.ifish.net/board/showthread.php?t=226190.

[20] “Fish, Raw, Mixed Species, Perch: Nutritional Value and Analysis.” Data from USDA. 2017. Web. https://www.nutritionvalue.org/Fish%2C_raw%2C_mixed_species%2C_perch_nutritional_value.html.

[21] “Perch Recipes - Food.com.” 2017. Web. http://www.food.com/topic/perch