Chub Mackerel

Scomber japonicus

Sometimes known as Blue Mackerel or Pacific Mackerel.

This species is wild-caught.

Summary

Chub Mackerel are found along both coasts of North America, but the fisheries in California and Mexico are most important. Chub Mackerel school at the surface of coastal waters, often with sardines and anchovy. Bycatch is usually low, because fishers set nets directly on schools. Sardines and anchovies caught in the process are sold. Impacts of fishing gear on habitat are also low, because the fishery uses pelagic seine nets that rarely contact the seafloor. Chub Mackerel are sold fresh and as fish meal, oil, and tuna bait.

Criterion	Points
Life History	3.25
Abundance	2.00
Habitat Quality and Fishing Gear Impacts	3.75
Management	3.25
Bycatch	3.25
Final Score (average of criteria)	3.10
Color

Final Score	Color
2.60 - 4.00
2.20 - 2.59
1.80 - 2.19
1.40 - 1.79
0.00 - 1.39

Last updated November 12, 2004.

Life History

Core Points (only one selection allowed)

If a value for intrinsic rate of increase (‘r’) is known, assign the score below based on this value. If no r-value is available, assign the score below for the correct age at 50% maturity for females if specified, or for the correct value of growth rate ('k'). If no estimates of r, age at 50% maturity, or k are available, assign the score below based on maximum age.

1.00	Intrinsic rate of increase <0.05; OR age at 50% maturity >10 years; OR growth rate <0.15; OR maximum age >30 years.
2.00	Intrinsic rate of increase = 0.05-0.15; OR age at 50% maturity = 5-10 years; OR a growth rate = 0.16–0.30; OR maximum age = 11-30 years.
3.00	Intrinsic rate of increase >0.16; OR age at 50% maturity = 1-5 years; OR growth rate >0.30; OR maximum age <11 years. The intrinsic rate of increase is unknown. All Chub Mackerel are sexually mature within four years, and some individuals mature by age one. The maximum recorded age is 11 years, but most commercially captured Chub Mackerel are less than 4 years old (PFMC 1998).

Points of Adjustment (multiple selections allowed)

-0.25	Species has special behaviors that make it especially vulnerable to fishing pressure (e.g., spawning aggregations; site fidelity; segregation by sex; migratory bottlenecks; unusual attraction to gear; etc.).
-0.25	Species has a strategy for sexual development that makes it especially vulnerable to fishing pressure (e.g., age at 50% maturity >20 years; sequential hermaphrodites; extremely low fecundity).
-0.25	Species has a small or restricted range (e.g., endemism; numerous evolutionarily significant units; restricted to one coastline; e.g., American lobster; striped bass; endemic reef fishes).
-0.25	Species exhibits high natural population variability driven by broad–scale environmental change (e.g., El Nino; decadal oscillations). Changes in climatic and oceanic conditions affect Chub Mackerel populations. El Nino Southern Oscillation (ENSO) events and environmental changes that occur over longer time-scales are linked to changes in Chub Mackerel abundance (D. Waldeck, pers. comm., 10/7/2004; PFMC 1998). Managers think that occasional, relatively large catches of Chub Mackerel in Oregon and Washington waters are related to ENSO events, perhaps reflecting movement of the fish into preferable habitat conditions (PFMC 2004).

+0.25	Species does not have special behaviors that increase ease or population consequences of capture OR has special behaviors that make it less vulnerable to fishing pressure (e.g., species is widely dispersed during spawning).
+0.25	Species has a strategy for sexual development that makes it especially resilient to fishing pressure (e.g., age at 50% maturity <1 year; extremely high fecundity). Once sexually mature, Chub Mackerel spawn whenever sufficient food and environmental conditions are available and are able to spawn daily or every other day (PMFC 1998). Therefore, the abundance of Chub Mackerel does not rely on spawning success within one short season or at a single spawning site, where temporarily poor conditions may decrease egg or hatching survival rates.
+0.25	Species is distributed over a very wide range (e.g., throughout an entire hemisphere or ocean basin; e.g., swordfish; tuna; Patagonian toothfish). Chub Mackerel are a cosmopolitan species, inhabiting temperate waters in the Atlantic and Pacific Oceans (Fishbase, 10/14/2004). In the eastern Pacific, they are found along the coast of North America from Banderas Bay, Mexico to southeastern Alaska, including the Gulf of California (PMFC 1998).
+0.25	Species does not exhibit high natural population variability driven by broad-scale environmental change (e.g., El Nino; decadal oscillations).

3.25	Points for Life History

Abundance

Core Points (only one selection allowed)

Compared to natural or un-fished level, the species population is:

1.00	Low: Abundance or biomass is <75% of BMSY or similar proxy (e.g., spawning potential ratio).
2.00	Medium: Abundance or biomass is 75–125% of BMSY or similar proxy; OR population is approaching or recovering from an overfished condition; OR adequate information on abundance or biomass is not available. The projected Chub Mackerel biomass estimate for July 1, 2004 was 81,383 metric tons (mt), which is well above the catch guideline of 13,269 mt set by the MSY Control Rule for Chub Mackerel (PFMC 2004). Although the population remains at relatively low levels compared to the populations of the 1980s and early 1990s, when the population peaked at 1.39 million mt, biomass levels that high are unusual and thought to only occur every 60 years (PFMC 2004).
3.00	High: Abundance or biomass is >125% of BMSY or similar proxy.

Points of Adjustment (multiple selections allowed)

-0.25	The population is declining over a generational time scale (as indicated by biomass estimates or standardized CPUE). Biomass has stabilized in the last 2 years but, overall, has declined since the 1980s and 1990s. Several strong year classes in the late 1970s produced a record peak in Chub Mackerel biomass, 1.39 million metric tons in 1982 (PFMC 2004). The population then declined to 10,438 metric tons in 2001, which was attributed to several weak year classes, relatively low reproductive success, and high fishing mortality in 1998. We chose not to subtract points here because Chub Mackerel biomass has recently stabilized and may be rebounding.
-0.25	Age, size or sex distribution is skewed relative to the natural condition (e.g., truncated size/age structure or anomalous sex distribution).
-0.25	Species is listed as “overfished” OR species is listed as “depleted”, “endangered”, or “threatened” by recognized national or international bodies. This species is not overfished.
-0.25	Current levels of abundance are likely to jeopardize the availability of food for other species or cause substantial change in the structure of the associated food web.

+0.25	The population is increasing over a generational time scale (as indicated by biomass estimates or standardized CPUE).
+0.25	Age, size or sex distribution is functionally normal.
+0.25	Species is close to virgin biomass.
+0.25	Current levels of abundance provide adequate food for other predators or are not known to affect the structure of the associated food web. Chub Mackerel are likely to be important prey of seabirds and have been observed in the diet of pelicans (PFMC 2001). There is no mention of directed research to assess whether the population abundance is adequate to sustain predator abundances. We chose not to award points until the role of Chub Mackerel in the coastal Pacific food web is further elucidated.

2.00	Points for Abundance

Habitat Quality and Fishing Gear Impacts

Core Points (only one selection allowed)

Select the option that most accurately describes the effect of the fishing method upon the habitat that it affects.

1.00	The fishing method causes great damage to physical and biogenic habitats (e.g., cyanide; blasting; bottom trawling; dredging).
2.00	The fishing method does moderate damage to physical and biogenic habitats (e.g., bottom gillnets; traps and pots; bottom longlines).
3.00	The fishing method does little damage to physical or biogenic habitats (e.g., hand picking; hand raking; hook and line; pelagic long lines; mid-water trawl or gillnet; purse seines). Chub Mackerel are fished with purse seines and lampara nets, which have lateral wings that surround fish schools from the sides. As the fish become crowded next to the vessel by the closing net, pumps are lowered into the water to pump the fish directly into the vessel's hold. Netted scoops (brails) may also be used (PFMC 2004). These fishing methods have little impact on habitats.

Points of Adjustment (multiple selections allowed)

-0.25	Habitat for this species is so compromised from non-fishery impacts that the ability of the habitat to support this species is substantially reduced (e.g., dams; pollution; coastal development).
-0.25	Critical habitat areas (e.g., spawning areas) for this species are not protected by management using time/area closures, marine reserves, etc.
-0.25	No efforts are being made to minimize damage from existing gear types OR new or modified gear is increasing habitat damage (e.g., fitting trawls with roller rigs or rockhopping gear; more robust gear for deep-sea fisheries).
-0.25	If gear impacts are substantial, resilience of affected habitats is very slow (e.g., deep water corals; rocky bottoms).

+0.25	Habitat for this species remains robust and viable and is capable of supporting this species. Habitat for the Chub Mackerel population fished in the U.S. is the pelagic coastal region off of the west coast of North America (PFMC 1998). There is no indication that habitat for Chub Mackerel is not robust.
+0.25	Critical habitat areas (e.g., spawning areas) for this species are protected by management using time/area closures, marine reserves, etc.
+0.25	Gear innovations are being implemented over a majority of the fishing area to minimize damage from gear types OR no innovations necessary because gear effects are minimal. Gear effects are likely to be minimal.
+0.25	If gear impacts are substantial, resilience of affected habitats is fast (e.g., mud or sandy bottoms) OR gear effects are minimal. Gear effects are likely to be minimal.

3.75	Points for Habitat Quality and Fishing Gear Impacts

Management

Core Points (only one selection allowed)

Select the option that most accurately describes the current management of the fisheries of this species.

1.00	Regulations are ineffective (e.g., illegal fishing or overfishing is occurring) OR the fishery is unregulated (i.e., no control rules are in effect).
2.00	Management measures are in place over a major portion over the species’ range but implementation has not met conservation goals OR management measures are in place but have not been in place long enough to determine if they are likely to achieve conservation and sustainability goals.
3.00	Substantial management measures are in place over a large portion of the species range and have demonstrated success in achieving conservation and sustainability goals. The PFMC's Coastal Pelagic Species Fishery Management Plan actively manages (i.e. harvest guidelines and fishing seasons are used) Chub Mackerel, and the council assesses the population annually. Fishing effort tracks the availability of Chub Mackerel in nearshore waters, which is influenced by environmental forces. The council constrains fishing effort with a conservative catch limit during years of high levels of biomass (Hill, K., pers. comm., 11/8/2004; PFMC 2004).

Points of Adjustment (multiple selections allowed)

-0.25	There is inadequate scientific monitoring of stock status, catch or fishing effort. There is little biological information (i.e. size and age composition of landings) available on Chub Mackerel that occur outside of the Southern California Bight, especially in the Ensenada, Mexico fishery, which catches a comparable volume to the California fishery. Lack of fishery-independent survey data and data on recruitment contribute to uncertainty in the biomass and recruitment models used to set catch guidelines. Incidental take of Chub Mackerel in Pacific Whiting and Salmon troll fisheries in the Pacific Northwest is unknown, and a reporting system is needed (PFMC 2004).
-0.25	Management does not explicitly address fishery effects on habitat, food webs, and ecosystems.
-0.25	This species is overfished and no recovery plan or an ineffective recovery plan is in place.
-0.25	Management has failed to reduce excess capacity in this fishery or implements subsidies that result in excess capacity in this fishery.

+0.25	There is adequate scientific monitoring, analysis and interpretation of stock status, catch and fishing effort.
+0.25	Management explicitly and effectively addresses fishery effects on habitat, food webs, and ecosystems.
+0.25	This species is overfished and there is a recovery plan (including benchmarks, timetables and methods to evaluate success) in place that is showing signs of success OR recovery plan is not needed. This species is not overfished.
+0.25	Management has taken action to control excess capacity or reduce subsidies that result in excess capacity OR no measures are necessary because fishery is not overcapitalized. Managers use a limited entry system to prevent overcapitalization of the fishery (K. Hill, pers. comm., 11/8/2004; PFMC 2004).

3.25	Points for Management

Bycatch

Core Points (only one selection allowed)

Select the option that most accurately describes the current level of bycatch and the consequences that result from fishing this species.

The term, "bycatch” used in this document excludes incidental catch of a species for which an adequate management framework exists.

The terms, “endangered, threatened, or protected,” used in this document refer to species status that is determined by national legislation such as the U.S. Endangered Species Act, the U.S. Marine Mammal Protection Act (or another nation's equivalent), the IUCN Red List, or a credible scientific body such as the American Fisheries Society.

1.00

Bycatch in this fishery is high (>100% of targeted landings), OR regularly includes a “threatened, endangered or protected species.”

2.00

Bycatch in this fishery is moderate (10-99% of targeted landings) AND does not regularly include “threatened, endangered or protected species” OR level of bycatch is unknown.

3.00

Bycatch in this fishery is low (<10% of targeted landings) and does not regularly include "threatened, endangered or protected species."

Bycatch in the Chub Mackerel fishery is low and most commonly consists of other species managed under the Coastal Pelagic Species Fishery Management Plan. The percentage of targeted landings that is comprised of bycatch in the Chub Mackerel fishery is unknown. Managers are certain that it is low, however. Port samples showed only a 3.4% occurrence of incidental catch in the Chub and Jack Mackerel and Pacific Sardine fisheries from 1985 to 1999.

The species caught as bycatch in the Chub Mackerel fisheries are generally landed and processed (i.e. sardines and anchovy) and therefore do not meet the definition of bycatch under the Magnuson-Stevens Act (PFMC 2004; D. Waldeck, pers. comm., 10/7/04). Fishers release large, non-CPS bycatch species alive before pumping or brailing the catch onboard (PFMC 2004).

Points of Adjustment (multiple selections allowed)

-0.25	Bycatch in this fishery is a contributing factor to the decline of “threatened, endangered, or protected species" and no effective measures are being taken to reduce it.
-0.25	Bycatch of targeted or non-targeted species (e.g., undersize individuals) in this fishery is high and no measures are being taken to reduce it.
-0.25	Bycatch of this species (e.g., undersize individuals) in other fisheries is high OR bycatch of this species in other fisheries inhibits its recovery, and no measures are being taken to reduce it.
-0.25	The continued removal of the bycatch species contributes to its decline.

+0.25	Measures taken over a major portion of the species range have been shown to reduce bycatch of “threatened, endangered, or protected species” or bycatch rates are no longer deemed to affect the abundance of the “protected” bycatch species OR no measures needed because fishery is highly selective (e.g., harpoon; spear).
+0.25	There is bycatch of targeted (e.g., undersize individuals) or non-targeted species in this fishery and measures (e.g., gear modifications) have been implemented that have been shown to reduce bycatch over a large portion of the species range OR no measures are needed because fishery is highly selective (e.g., harpoon; spear).
+0.25	Bycatch of this species in other fisheries is low OR bycatch of this species in other fisheries inhibits its recovery, but effective measures are being taken to reduce it over a large portion of the range. The catch guideline set for the Chub Mackerel fishery incorporates consideration of incidental catch of the species in other Coastal Pelagic Species fisheries. For the 2003-4 season, managers established a 10,652 mt catch guideline, with 3,152 mt set aside for incidental catch in other fisheries. Bycatch of Chub Mackerel in other fisheries is low. When Chub Mackerel are incidentally caught in the other Coastal Pelagic Species fisheries, they are generally sold. In 2000, a regulation was implemented that no more than 20% by weight of any landing of Pacific Sardine, Northern Anchovy, Jack Mackerel, or Market Squid may consist of Chub Mackerel (PFMC 2004). The Pacific Whiting and salmon troll fisheries catch Chub Mackerel as bycatch to an unknown degree (PFMC 2004).
+0.25	The continued removal of the bycatch species in the targeted fishery has had or will likely have little or no impact on populations of the bycatch species OR there are no significant bycatch concerns because the fishery is highly selective (e.g., harpoon; spear).

3.25	Points for Bycatch

References

Fishbase. Accessed on 10/14/2004 at http://www.fishbase.org.

Hill, K. NOAA. Personal communication. 11/8.2004.

NOAA Trade Statistics. Accessed on 10/1/2004 at http://www.st.nmfs.gov/st1/commercial/landings/annual_landings.html.

Pacific Fishery Management Council (PFMC). June 2004. Status of the Pacific Coast Coastal Pelagic Species Fishery and Recommended Acceptable Biological Catches, Stock Assessment and Fishery Evaluation.

PFMC. March 2001. Amendment 9 to the Coastal Pelagic Species Management Plan. Environmental Assessment/Regulatory Impact Review and Determination of the Impact on Small Businesses.

PFMC. December 1998. Amendment 8 to the Northern Anchovy Fishery Management Plan: The Coastal Pelagic Species Fishery Management Plan.

Waldeck, D. NOAA. Personal communication. 10/7/2004.