Mahimahi - pole and troll caught |
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Sometimes known as Dolphinfish, Clipper, Dorado
This Species is Wild Caught
Summary
Fast-growing, short-lived species, Mahimahi potentially can withstand high fishing pressure. Pole- or troll-caught are better than longline-caught because fewer unintended fish and marine mammals are taken, and there is no problem of seabird and marine turtle bycatch.
| CRITERION | Points |
|---|---|
| Life History | 3.00 |
| Abundance | 2.00 |
| Habitat Quality and Fishing Gear Impacts | 3.75 |
| Management | 0.75 |
| Bycatch | 3.75 |
| Final Score | 2.65 |
| Color | |
| Final Score | Color |
|---|---|
| 2.60 - 4.00 | |
| 2.20 - 2.59 |  |
| 1.80 - 2.19 |  |
| 1.40 - 1.79 |  |
| 0.00 - 1.39 |  |
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. No value for intrinsic rate of increase was available. Mahi reach sexual maturity in 4-5 months to one year (Fishbase, 2003; Palko et al., 1982). Fishbase (2003) reports a mahi k value as 0.4 to 1.2. The maximum reported age is 5 years (Fishbase, 2003). |
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.). Mahi aggregate around floating objects, making them easier to locate. Consequently, fishers can use attracting devices including cork planks, or floating bundles of bamboo reeds to concentrate fish (Fishbase, 2003). | |
| -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). Mahi population abundance is highly susceptible to ocean regime shifts (Paulo Bartrum, personal communication, Akala Products, 24 July, 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). Because they mature in less than one year and live only a maximum of five years, we consider this species to have a life history strategy with high potential for resilience to fishing pressure. Fishbase (2003) also describes this species' resilience as 'high'. | |
| +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). Mahi are distributed worldwide in tropical and subtropical ocean waters (Prager 2000). They are a highly migratory species (Fishbase, 2003). | |
| +0.25 | Species does not exhibit high natural population variability driven by broad-scale environmental change (e.g., El Nino; decadal oscillations).
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| 3.00 | 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. There is limited information available on abundance of Mahi worldwide, as no formal assessments have been conducted. In the U.S., there is no statistics program in place that is specifically aimed at sampling the species, and international agencies that monitor other highly migratory species (e.g. IATTC, ICCAT) have not assessed abundance of Mahi. The only available report is an exploratory assessment of Mahi based on U.S. landings from the Atlantic Ocean and Gulf of Mexico. This assessment developed an index of relative abundance using data from the U.S. longline fishery and estimated that stock status in the U.S. Western Atlantic was above Bmsy in 1998 (Prager 2000). |
| 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). | |
| -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. | |
| -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). The abundance index used in Prager (2000) indicates an increasing trend in stock size in the U.S. Atlantic. This abundance index, however, has a low level of certainty. In the U.S. Western Pacific, CPUE has been stable with no increasing or decreasing trends. Elsewhere, there are no data on trends available. No points were added or subtracted here to account for lack of data on trends. | |
| +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. | |
| 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). Worldwide, the majority of dolphinfish are taken as incidental catch in fisheries targeting other species. They are mostly caught in pelagic longline fisheries targeting tunas and swordfish, as well as in purse seine fisheries. However, there are commercial pole/troll fisheries in the U.S. South Atlantic, Gulf of Mexico, and Hawaii. Additionally, some recreational fisheries using pole/troll gear may sell their catch. In the United States, 90% of the domestic catch is taken by recreational fisheries, which largely use hook and line or troll methods. Some of the recreational catch may be sold in local markets, as charter boat captains can hold commercial permits. (Branstedder, NMFS, personal comm. 2/2003) All of these gear types have a relatively low impact on habitat. |
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. Worldwide, there is very little information available on migrational patterns and habitat areas. | |
| -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. Dolphinfish is an oceanic fish. We consider open water habitat to be relatively robust and viable. | |
| +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. The effects of pole and troll gear on habitat are 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. The effects of pole and troll gear on habitat are 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). There is no international management framework in place for Mahi nor do individual countries have management measures in place specifically addressing the management of Mahi. Recreational bag limits for Mahi are in place in some states in the U.S. Under the Coastal Migratory Species Fishery Management Plan for the Gulf of Mexico and the South Atlantic, a permit is required for catching Mahi, but no management measures exist. Mahi is a Pelagic Management Unit Species in the Western Pacific Regional Fishery Management Council's Pelagics Fishery Management Plan, but there are no regulations in place specifically dealing with the management of Mahi. |
| 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. |
Points of Adjustment (multiple selections allowed)
| -0.25 | There is inadequate scientific monitoring of stock status, catch or fishing effort. No formal assessments of Mahi have been conducted. | |
| -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. | |
| +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. | |
| 0.75 | 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." Although bycatch is not monitored adequately in pole and troll Mahi fisheries (including recreational fisheries where catch is sold), pole and troll gear have relatively low bycatch. |
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). Pole and troll fisheries have few discards and very low bycatch of non-targeted species. No measures are needed because they are not known to have any bycatch of threatened, endangered or protected species. They are a model for selective fisheries. | |
| +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). No measures are needed because pole and troll fisheries have few discards and very low bycatch of non-targeted species. | |
| +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. | |
| +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). There are no significant bycatch concerns with pole and troll fisheries. They are a model for selective fisheries. | |
| 3.75 | Points for Bycatch | |
Reference
Branstedder, Steven, National Marine Fisheries Service, personal communication, February, 2003)
Crowder, Larry B. and Myers, Ransom A. 2001 First Annual Report to the Pew Charitable Trusts. A Comprehensive Study of the Ecological Impacts of the Worldwide Pelagic Longline Industry.
Fishbase, March 8, 2002. Online at: http://www.fishbase.org/Summary/SpeciesSummary.cfm?genusname=Coryphaena&speciesname=hippurus
Prager, Michael. National Marine Fisheries Service. 2000. Exploratory Assessment of Dolphinfish, Coryphaena hippurus, based on U.S. landings from the Atlantic Ocean and Gulf of Mexico.
Fish Key
 | Species is relatively abundant, and fishing/farming methods cause little damage to habitat and other wildlife. |
 | Species has medium to high levels of abundance, or fishing/farming methods cause some damage to the environment. |
 | Some problems exist with this species' status or catch/farming methods, or information is insufficient for evaluating. |
 | Species abundance is generally low, or fishing/farming methods typically have large environmental impact. |
 | Species has a combination of problems such as overfishing, high bycatch, and poor management; or farming methods have serious environmental impacts. |
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A fishery targeting this species has been certified as sustainable and well managed to the Marine Stewardship Council's environmental standard. Learn more at www.msc.org. |  |
These fish contain levels of mercury or PCBs that may pose a health risk to adults and children. Please refer to http://www.edf.org/seafood for more details. |
