(DRAFT) - Taxonomy
Species marlin, white
Species Id M010408
Date 26 AUG 96
TAXONOMY
NAME - marlin, white
OTHER COMMON NAMES -
ELEMENT CODE -
CATEGORY - Fish
PHYLUM AND SUBPHYLUM - Chordata,
CLASS AND SUBCLASS - Osteichthyes (Bony fishes),
ORDER AND SUBORDER - Perciformes,
FAMILY AND SUBFAMILY - Istiophoridae (Billfishes),
GENUS AND SUBGENUS - Tetrapturus,
SPECIES AND SSP - albidus,
SCIENTIFIC NAME - Tetrapturus albidus
AUTHORITY - Poey
TAXONOMY REFERENCES - 190
Taxonomy - 1 (DRAFT) - Status
Species marlin, white
Species Id M010408
Date 26 AUG 96
STATUS
Coded Status
Sport Fish
Game (Consumptive Recreational)
Existing, FMP exists
Commercial/consumption
Commercial
REFERENCES FOR STATUS - 182, 111 and 189
COMMENTS ON STATUS -
A Billfish Fishery Management Plan was prepared jointly by the South
Atlantic, New England, Mid-Atlantic, Gulf of Mexico, and Caribbean Fishery
Management Councils. It establishes a management regime for billfishes
harvested from the management unit and possessed shoreward of the outer
boundary of the EEZ (Exclusive Economic Zone) of the Atlantic Ocean,
Gulf of Mexico and Caribbean Sea.*111*
The White Marlin is the most frequently caught marlin along the east coast
of the United States. This oceanic, migratory species is a popular trophy
fish.*182*
Status - 1 (DRAFT) - Distribution
Species marlin, white
Species Id M010408
Date 26 AUG 96
DISTRIBUTION
Distribution - 1 HABITAT ASSOCIATIONS
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Marine OW0 H
REFERENCES FOR NWI - 111
COMMENTS ON HABITAT ASSOCIATIONS -
The habitat for the billfishes in the management unit is the oceanic
pelagic waters of the Atlantic Ocean. Blue and white marlin, sailfish and
spearfish venture into coastal waters only occasionally, usually in areas
such as the Caribbean Islands where there is little continental shelf or in
southeast Florida, where the shelf is very narrow and the Gulf Stream is in
close proximity to shore. Because of their oceanic nature, the specific
habitat interactions of these species are not well known. White marlin are
generally more oceanic and more common at higher latitudes than some
billfish such as sailfish. Like all oceanic pelagics they are often
associated with current boundaries, upwellings, thermal fronts and other
oceanic features that act to concentrate nutrients or food. Fisheries thus
are concentrated in such areas.
The habitat of the billfishes is the water column itself. Because of their
oceanic nature, changes to the habitat of sufficient magnitude to directly
impact the billfish fishery are relatively unlikely. However, oil spils,
ocean dumping, OTEC projects (Offshore Thermal Energy Conversion), and the
general degradation of the oceanic environment may impact the survival of
larvae and possibly adults (either directly or through the food
chain).*111*
Water temperature appears to be a major factor influencing the distribution
of billfishes. They are generally found in waters with surface
temperatures above 70 degrees F (21 degrees C).
Major currents also play an important role in the distribution and
migration of billfishes. Concentrations of sailfish, white marlin and blue
marlin are found within or near the Gulf Stream, which flows in a
northeasterly direction along the Atlantic coast of the U.S. at varying
distances from shore. In the northeastern Gulf of Mexico, billfishes are
abundant in and around the Loop Current. The northward extent of their
migration into the Gulf appears to be related to the northward extent of
the current's penetrations. The northward migration of white marlin from
wintering areas off northern South America occurs in association with the
Antilles Current, which flows on the north side of the Caribbean Island
chain.
Localized occurrence of blue and white marlin is influenced by bottom
topography. Steep drop-offs, submarine canyons, and shoals, when located
in areas with suitable water conditions, often harbor feeding
concentrations of these species. Along the Atlantic coast of the United
States, important topographical features of this nature include the Five
Fathom Bank off southern New Jersey; the Cigar southeast of the Virginia
Capes; the Jack Spot off Maryland; Hudson Canyon, southeast of New York
City; Wilmington, Baltimore and Washington Canyons off the Delmarva
Peninsula; and Norfolk Canyon off the Virginia Capes. DeSoto Canyon in the
northeastern Gulf of Mexico and drop-offs in the Bahamas, Puerto Rico and
the Virgin Islands also attract feeding concentrations of marlins.*111*
Habitat Associations - 1 (DRAFT) - Food Habits
Species marlin, white
Species Id M010408
Date 26 AUG 96
FOOD HABITS
TROPHIC LEVEL -
CARNIVORE
REFERENCES FOR TROPHIC LEVEL - 189
LIFESTAGE FOOD FOOD PART
General Squid, Octopus Not Specified
General Osteichthyes Not Specified
REFERENCES FOR GENERAL FOOD - 189
COMMENTS ON FOOD -
White marlin appear to be primarily daytime feeders, although they may
occasionally feed at night as well. Stomachs of white marlin in the
northeastern Gulf of Mexico have been reported to most frequently contain
squid, mackerel (Auxis sp.), tuna (Euthynnus sp.), and Atlantic moonfish
(Vomer setapinnis). Others have noted the importance of squid in the white
marlin diet. The round herring, Etrumeus teres, has been reported to be
occur most frequently in stomachs of white marlin caught off the middle
Atlantic coast. It has been hypothesized that differences in diet between
areas reflects differences in the distribution and abundance of prey
species.
White marlin may feed both in shallow and deep waters, both in coastal areas
and in the open sea. Sargassum lines have been suggested as feeding areas
for white marlin in the Gulf of Mexico. Feeding concentrations have also
been observed in locations such as submarine canyons, shoals, and steep
drop-offs.*189*
Food Habits - 1 (DRAFT) - Environment Associations
Species marlin, white
Species Id M010408
Date 26 AUG 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G Water Temperature: Between 21-27 degrees C
G Water Temperature: Between 15-21 degrees C
G
REFERENCES FOR ENVIRONMENTAL ASSOC_ - 189
COMMENTS ON ENVIRONMENTAL ASSOCIATIONS -
Temperature:
The white marlin is usually found in water with surface temperatures over
66 degrees F (19 degrees C) and lower than 81 degrees F (27 degrees C).
Optimal temperature for the species has been suggested to be 75 degrees F
(24 degrees C).*189*
Salinity:
White marlin show a preference for waters with relatively high surface
salinities, in the range of 35 ppt - 37 ppt.*189*
Environment Associations - 1 (DRAFT) - Life History
Species marlin, white
Species Id M010408
Date 26 AUG 96
LIFE HISTORY
Migration:
The degree of concentration of white marlin in the western North Atlantic
varies greatly both geographically and seasonally. Indications are that
white marlin migrate seasonally from a summer habitat in the northern Gulf
of Mexico or off the Middle Atlantic coast (from Cape Hatteras to Cape Cod)
to a winter habitat in the southern Caribbean (northern coast of South
America from Colombia to the Guianas). The latter migration pattern is
northward along the length of the Middle Atlantic summering grounds,
easterly offshore in late summer and early fall, and then southward to the
wintering grounds. No trans-Atlantic or trans-equatorial migrations have
been recorded despite a substantial fishery for white marlin in the South
Atlantic, particularly off Brazil.*189*
The migration northward in the spring is via the Yucatan Channel and the
Straits of Florida for some; through the Passages of the Greater Antilles
for others; and still others migrate northward with the Antilles Current
and pass east of the West Indies and the Bahamas.*189*
The northern migration of the species appears to be related to water
temperature. The white marlin reaches higher latitudes as the water
warms.*189*
Reproduction:
Researchers have reported that white marlin reach sexual maturity at 51
inches (130 cm) eye-fork length, or at about 44 pounds (20 kg).
Fecundity estimates range from 3.8 to 10.5 million eggs for fish weighing
between 59 and 82 pounds.*189*
Spawning:
Information regarding the spawning grounds of the white marlin is
incomplete. Three spawning grounds have been suggested in the western North
Atlantic: northwest of Grand Bahama Island, southwest of Bermuda, and
northeast of Little Bahama Bank off Abaco Islands. A high percentage of
post-spawning females have been found in the sport fishery of Ocean City,
MD., which led researchers to conclude that spawning probably takes place
somewhere between the Bahamas and Cape Hatteras, NC. Nearly ripe females
have been found off Puerto Rico in April and white marlin spawn in the
Florida Straits during April and May.*189*
Age and Growth Characteristics:
Accurate aging techniques have not been developed for the white marlin.
Consequently, information regarding age-size relationships, age composition
of the population, size and age at first maturity, and growth rate is
limited. In an unpublished paper, white marlins were aged using otoliths.
Male and female marlins were determined to be between 0 and 16 years of age.
Age of both sexes combined averaged 5.7 years, with 4-5 year olds
dominating.*189*
At sizes smaller than 68 inches (173 cm) fork length, females tend to be
heavier than males of comparable length. In addition, females tend to
attain both greater lengths and greater weights than males.
Abundance and Present Condition:
From 1977 to 1979 the white marlin catch averaged approximately one half of
Life History - 1 (DRAFT) - Life History
Species marlin, white
Species Id M010408
Date 26 AUG 96
the average of the previous 10 years. Although fishing effort has declined
somewhat recently, the decline has not been as great as the decline in
catch. The present status of the stock is unclear, but the recent low
catches are cause for concern.*189*
Predation:
Predation by dolphins on billfish in larval and juvenile stages is
significant. Shark attacks on billfishes hooked on longline gear have been
observed frequently, but the degree of predation by sharks on free swimming
billfishes is unknown.*189*
Competition:
Studies have indicated that the centers of billfish abundance coincide
during certain seasons of the year. Since the dietary preferences of the
three species (white and blue marlin and sailfish) are similar (fish and
squid are important food items for all three), it is likely that some
competition for food and space occurs. An inverse relationship between the
relative abundance of white and blue marlin during the sport fishing season
in the Gulf of Mexico has been observed. It is possible that a competitive
relationship of some sort exists between the two species. However, these
differences in relative abundance could also be due to changes in fishing
method or location of effort directed to one or the other species, i.e.,
what types of bait or whether "light" or "heavy" tackle is being used.*189*
Population Trends:
Considering the number of countries currently participating in the billfish
fishery outside of national jurisdictions, the probable future condition of
the stocks cannot be accurately assessed without knowing the long range
intentions of these fisheries with regard to their high seas operations and
coastal fisheries. However, in view of the increasing world demand for
protein, accompanied by increasing prices for tuna and billfish in world
markets, sustained or increasing fishing effort for billfishes can
reasonably be expected.
The average size of both blue and white marlin has increased in recent
catches. Increase in size would be consistent with (1) a general decline in
the number of young fish entering the fishery, (2) the progression of a
large year-class (or year-classes) through the fishery, or (3) shifts of
the fishery to times or places where older marlins are disproportionately
abundant. Which of these is the cause of increasing size of fish in the
catch is not apparent from available information. However, fishing effort
has shifted spatially and temporally in recent years.*189*
REFERENCES FOR LIFE HISTORY- 189
Life History - 2 (DRAFT) - Management Practices
Species marlin, white
Species Id M010408
Date 26 AUG 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Existing Regulating harvest of species being described
Existing Prohibiting harvest of species being described
Existing Regulating harvest - setting size limits
Existing Regulating commercial harvest levels
Existing Other management practices [specified in comments]
Beneficial Controlling pollution [thermal, chemical, physical]
REFERENCES FOR BENEFICIAL MANAGEMENT PRACTICES - 111
REFERENCES FOR EXISTING MANAGEMENT PRACTICES - 111
COMMENTS ON MANAGEMENT PRACTICES -
Economic, Social and Ecological Considerations of Management:
The higher the availability of billfishes within the EEZ (Exclusive Economic
Zone), the greater the likelihood that U.S. anglers will catch a billfish.
Any increase in the likelihood of success should have a substantial,
positive impact on the socio-economic values of the fishery. Thus, the
optimum yield will result from reserving to the U.S. recreational fishery
the most billfish possible occurring in the EEZ at any given time. The
recreational billfish fishery plays a significant role in the economic and
social well being of a great many people.*111*
Fishery Management Plan:
A Billfish Fishery Management Plan was prepared jointly by the South
Atlantic, New England, Mid-Atlantic, Gulf of Mexico, and Caribbean Fishery
Management Councils. It establishes a management regime for billfishes
harvested from the management unit and possessed shoreward of the outer
boundary of the EEZ (Exclusive Economic Zone) of the Atlantic Ocean,
Gulf of Mexico and Caribbean Sea.*111*
Summary of FMP (May, 1988):
Management Measure #l: No Sale Provision
The no sale provision is for the express purpose of preventing a commercial
market for these species from developing, thus preventing the primary
objective of the FMP from being realized.
Management Measure #2: Minimum Sizes
The intent of this management measure is to significantly reduce billfish
mortality in the recreational fishery by releasing more billfish alive,
which will increase the availability to the recreational fishery, thus
helping accomplish the plan's principal objective.
Management Measure #3: No Possession By Longliners & Drift Net Vessels:
This measure is intended to maximize the release of live billfish by those
commercial vessels that would routinely catch them in the course of their
commercial fishing operation. Since the objective of this plan is to
maximize the availability of billfishes to the recreational fishery, any
measure which results in the release of live billfish will help accomplish
Management Practices - 1 (DRAFT) - Management Practices
Species marlin, white
Species Id M010408
Date 26 AUG 96
that objective.
Management Measure #4: Data Reporting Requirements
Data reporting requirements consist of a recommendation for the continuation
of the existing logbook requirement and voluntary observer program as
specified in the swordfish FMP and mandatory reporting of catch and effort
data for recreational fishing tournaments.
Management Measure #5: Puerto Rican Handline Exemption:
A traditional, artisanal handline fishery in Puerto Rico has a small bycatch
of billfishes, primarily blue marlin. The capture of a billfish in this
small-scale fishery is a rare, but fortuitous event for the few artisanal
fishermen in Puerto Rico. This measure provides the only exemption to the
no sale provision, complicating enforcement, and providing a potential
loophole through which illegally harvested billfish may enter commercial
markets. To lessen these impacts restrictions have been placed on this
exemption.*111*
Foreign Longline Fishery:
Longline catch rates for white marlin, blue marlin and sailfish/spearfish
within 200 miles of the U.S. have declined markedly in recent years. In
recent years, Japanese fishing effort has been reduced dramatically in the
EEZ. In 1986, for example, 272 white marlin and 37 blue marlin were
recorded by U.S. observers (100 percent coverage). Of those, 54 percent of
the white marlin and 57 percent of the blue marlin were dead. The Japanese
have agreed not to fish in the Gulf of Mexico and have not done so since
1982.*189*
Need for International Management Plan:
There is a pressing need for the rapid development and institution of an
international management plan in order to maintain the stocks of billfish in
an expanding fishery. Other unregulated common property fisheries have
overfished the population to varying degrees ranging from reducing annual
yields below MSY (maximum sustainable yield - the largest quantity of fish
that can be harvested annually from a resource without reducing its
long-term productive potential), through economic disruption of the fishery
to its economic extinction. In the absence of an international fishing
regime, further increases in the level of effort for billfishes are likely.
Considering the status of these stocks (billfishes), such increases in
effort are not likely to produce increases in yield, at least for blue and
white marlin, and could result in recruitment overfishing and depletion of
the stocks.*189*
Habitat areas of Particular Concern:
There are no habitat areas of particular concern in the sense that the term
is generally applied (e.g., estuarine nurseries in the case of estuarine
dependent species). The billfishes are highly migratory, oceanic species
whose habitat and environmental requirements during early stages of their
life cycles are not well known. Billfish spawning grounds are at or near
the surface of oceanic waters relatively far from coastal sources of
pollution. Offshore pollutants, such as oil spills, may be deleterious to
the young stages. Billfish can also be influenced by subsurface and
substrate pollutants, such as heavy metals, pesticides and radionuclides,
Management Practices - 2 (DRAFT) - Management Practices
Species marlin, white
Species Id M010408
Date 26 AUG 96
through the food chain. Billfish living on or near canyons of the
continental shelf may be affected by pollutants carried through direct ocean
dumping.
Oil spills, ocean dumping, OTEC projects (Offshore Thermal Energy
Conversion), and the general degradation of the oceanic environment may
impact the survival of larvae and possibly adults. The effects of
sub-lethal concentrations of chemical and other pollutant on these species
is not known, but their oceanic distribution suggests a requirement for
extremely high water quality. Any degradation of this water quality can be
expected to impact their survival which would obviously impact the fishery.
Habitat Preservation, Protection and Restoration Recommendations:
1) Research should be conducted to quantify the impacts of ocean disposal
of dredge materials, industrial waste and sewage sludge on oceanic pelagics
such as billfish.
2) The disposal of contaminated sewage sludge, industrial waste and
contaminated dredge material that would degrade the environmental quality of
the marine environment utilized by billfish should be prohibited.*111*
Description of Vessels and Gear Employed:
Sport fishing for marlins is done with rod and reel. The boats used in the
U.S. sport fishery for billfishes range from 16 to more than 65 feet in
length and the method of power ranges from outboard engines to large
diesels. Marlin fishing generally requires a large (greater than 25 feet in
length), inboard, usually diesel-powered vessel because of the distance that
has to be traveled to reach suitable fishing grounds, as many as 75 to 100
miles from shore off many areas on the Atlantic and Gulf coasts. The use of
smaller outboard powered boats (in the 16 to 25 foot range) in the fishery
is particularly evident off the southeast coast of Florida from Key West to
Ft. Pierce and in the northern Gulf of Mexico and the Caribbean where
productive billfish fishing waters are only a few miles from shore. The
development of small, fast, sea worthy fishing boats (20-30 feet in length)
and reliable high-powered outboard engines has made even the offshore
fishing grounds accessible to a great many anglers.*111*
Fishing Seasons and Areas:
The U.S. recreational fishery for billfishes is conducted from every state
along the Atlantic and Gulf coasts from Massachusetts southward, as well as
from Puerto Rico and the Virgin Islands. Anglers from the U.S. also fish
extensively in foreign waters, particularly offshore of the Bahamas,
Venezuela, Mexico, Dominican Republic and British Virgin Islands.
The fishery is, for the most part, a seasonal one, which coincides with the
months of highest availability of billfishes within the EEZ. Off the
Atlantic and Gulf coasts of the U.S., recreational activity is most intense
from April through October. In the Caribbean EEZ, fishing for billfish is a
year-round activity with seasonal peaks for each species.*111*
Management Practices - 3 (DRAFT) - References
Species marlin, white
Species Id M010408
Date 26 AUG 96
References
111 South Atlantic Fishery Management Council. 1988. Fishery
Management Plan, Final Environmental Impact Statement,
Regulatory Impact Review, and Initial Regulatory Flexibility
Analysis for the Atlantic Billfishes. South Atlantic Fishery
Management Council Charleston, SC pp 26.
182 * Manooch, Charles S. III. 1984. Fisherman's Guide to the
Fishes of the Southeastern United States. North Carolina State
Museum of Natural History Raleigh, North Carolina:362.
183 * Gusey, William F. 1981. The Fish and Wildlife Resources of
the South Atlantic Coast. (ed.). Environmental Affairs, Shell
Oil Company Houston, Texas:552.
References - 1