Biodiversity Legal Foundation
P.O. Box 278
Louisville, CO 80027
February 14, 2002
Dr. William Hogarth
Assistant Administrator for Fisheries
National Marine Fisheries Service
1315 East-West Highway
Silver Spring, Maryland 20910
Re: Atlantic White Marlin Critical Habitat Designation
Dear Dr. Hogarth:
These comments are submitted on behalf of the Biodiversity Legal Foundation and myself in response to the agency's request for public comment (66 FR 65676, December 20, 2001) on the designation of critical habitat of Atlantic white marlin. Our comments supplement and should be read in conjunction with those contained in our joint petition to you dated August 31, 2001, requesting that this species be listed as a "threatened" or as an "endangered species" throughout its range and that its critical habitat be designated and protected under the authorities provided by the Endangered Species Act and other statutes.
We believe that this species' critical habitats (particularly its prime spawning and feeding areas), at least for the North Atlantic sub-population, are clearly indicated on maps showing those areas where U.S. longliners reported the highest concentration of white marlin in their catches. We refer to such areas as "hot spots." To assist the agency in identifying and designating the white marlin's critical habitats, we have undertaken an effort to determine and document the location of at least some of its primary spawning, nursery and feeding area "hot spots" and its major migration routes. This is based on information from a variety of sources including the published literature and more than a decade of commercial and recreational catch records. Enclosed are our detailed comments identifying those areas that are critical habitat of Atlantic white marlin.
As you know, the latest international stock assessment indicates that Atlantic white marlin are rapidly nearing extinction, which moved us to file our petition. At its current rate of decline the species is less than five years from functional extinction, as described in detail in our petition. The latest management recommendations by the International Commission for the Conservation of Atlantic Tunas (ICCAT) will slow but not stop the rapid decline in abundance. ICCAT had directed that all live marlin be released, but 30 percent caught on longlines (which cause 92 percent of the mortality) come to the boat dead. Therefore, the existing rate of mortality (8 times the sustainable level and rising rapidly) can be reduced by no more than 70 percent (to not less than 2.4 times the sustainable level). With its biomass declining rapidly and last estimated to be only 13 percent of its maximum sustainable yield at the end of 1999, this species was already much too close to extinction. Over two years of additional mortality has now occurred. There is no time to waste if this species is to be saved.
Those "hot spots" in the U.S. Exclusive Economic Zone (EEZ), where the greatest number of marlin are caught and killed by commercial vessels, should be placed off limits to longlines as soon as possible. Doing so will eliminate about 85 percent of the white marlin mortality caused by U.S. longlines, but it will deny access to only about 2 percent of the area fished annually by these vessels. Closing the "hot spots" to commercial fishing has the added benefit of protecting the other large pelagic species (including swordfish, bluefin tuna, bigeye tuna, sailfish, spearfish, and many species of large sharks) that concentrate in these same highly productive areas and whose populations have also declined to dangerously low levels. The "hot spots" that should be closed are located on the edge of the continental shelf (roughly in a narrow band between the 600 and 6,000 ft. depth contours). They can be seen easily on maps prepared by Dr. Pamela Mace of NMFS based on U.S. longliners' mandatory logbook reports. She has produced color maps in exquisite detail (by quarter for 1986 through 1996). Maps for the two most recent complete years are reproduced in the petition (Appendix 8).
Many consider white marlin to be the perfect gamefish. It is central to most Atlantic billfish tournaments. As noted in our petition, with about 400 big game fishing tournaments held each year, many fishing "destinations" already documented as contributing tens of millions of dollars in annual regional economic activity (there are an estimated 230,000 billfish anglers in the U.S. who spend an estimated $2.13 billion annually on fishing), and big game fishing (almost totally catch and release) already large and growing in popularity, the species is simply too valuable to lose.
As the federal steward of the nation's living marine resources, it is the responsibility of NMFS to act aggressively before this magnificent and extremely valuable premiere game fish species vanishes forever. Therefore, we request that NMFS act on an emergency basis to: (1) designate, to the degree it is known, the white marlin's critical habitat throughout its range, (2) prohibit commercial fishing for highly migratory species in those white marlin "hot spots" located within the U.S. EEZ (including the Caribbean), and (3) seek international agreements (at ICCAT) to further identify and close their spawning area "hot spots" to commercial fishing for large pelagic species.
James R. Chambers
Critical Habitat of Atlantic White Marlin
These comments are provided to assist the National Marine Fisheries Service (NMFS) in identifying and designating critical habitat of Atlantic white marlin, particularly that of the northern hemisphere. Our comments are based on published literature and information from more than a decade of commercial and recreational catch records.
White marlin have evolved by exploiting particular habitats throughout their life cycle from egg to adult. They spawn, feed and migrate within specific areas having characteristics that maximize their growth and survival. Those areas which are their critical habitats - areas essential to their survival - include their primary spawning sites, nursery grounds, feeding grounds and migratory routes. We can get a very good idea of where such areas lie by examining records of where longline catches are made throughout the year. Additional confirmation is provided by noting the peak seasons of the top billfish "destinations" and the timing of the approximately 400 sport fishing tournaments held each year throughout the range of the white marlin. As described by de Sylva and Breder (1997), Baglin (1979), Mather et al. (1975), Nakamura (1985) and Arfelli (1986), previous collections of eggs and larvae and records of adults in spawning condition indicate the location of at least some of their primary spawning areas.
The following discussion of critical habitats relates primarily to the Atlantic white marlin of the northern hemisphere. We are convinced that, as has already been accepted for Atlantic swordfish, there are two separate and distinct sub-populations or stocks of Atlantic white marlin. (We also believe the same is true of Atlantic blue marlin.) The basis for this position is discussed in detail in the petition filed jointly on September 3, 2001, by the Biodiversity Legal Foundation and James R. Chambers requesting the National Marine Fisheries Service to list white marlin as a threatened or as an endangered species throughout its Atlantic Ocean range and to designate and protect its critical habitat under authority provided by the Endangered Species Act and other statutes. (The references and Appendices mentioned below refer to those contained in that petition.) We believe the two hemispheres' sub-populations of white (and blue) marlin do not interbreed. One sub-population inhabits the northern hemisphere and spawns in the Caribbean area during its spring (March through mid-June). The other inhabits the southern hemisphere and spawns in the region of the Royal Charlotte Bank off Cabo Frio in central Brazil during its spring to early summer (Arfelli, 1986). These too spawning epicenters can be seen in ICCAT/SCRS maps showing quarterly international catch records (SCRS/00/23). As the primary southern hemisphere spawning area for Atlantic white marlin, the Royal Charlotte Bank area is obviously critical habitat.
The epicenters of these two sub-populations' spawning areas are separated by approximately 5,000 miles and spawning occurs six months apart. As noted in the petition, white marlin tagged in the western North Atlantic have been recaptured on the eastern side of the North Atlantic. However, there has never been a verifiable case of a white marlin tagged in the northern hemisphere crossing the equator and being recaptured in the southern hemisphere. So, even if a white marlin from the northern hemisphere's population that was reproductively ready to spawn (March through mid-June) was to stray into the southern hemisphere (an additional journey of 5,000 miles), it would find that the southern hemisphere's white marlin would not be ready to spawn for at least another five months.
Large areas of the western North Atlantic Ocean, including the Caribbean Sea and Gulf of Mexico, are fished throughout the year by U.S. longline vessels providing a very extensive "sampling" record of billfish distribution. Their annual coverage is depicted for 1990 through 1994 in Figures 4 through 8 by Cramer (1996a, Appendix 12). These maps show a very broad distribution of longline effort by U.S. vessels throughout the western North Atlantic Ocean. As will be shown below, this longline effort is extensive in its areal extent, and is much broader than are the small spawning and feeding areas of white marlin that we refer to as "hot spots." What is also apparent is that these white marlin "hot spots" do not necessarily coincide with areas of greatest longline effort or catch per unit effort. Thus, they are not just those areas that longliners fish most heavily. They are simply very small, distinct areas where white marlin are highly concentrated. As will be shown, these "hot spots" are also areas where blue marlin, swordfish and sailfish are also highly concentrated during the same periods of the year.
Catch data from mandatory logbook reports received from U.S. longline vessels were used by Dr. Pamela Mace of NMFS to map the concentrations of white marlin by quarter over a period of 10 years from mid-1986 through mid-1996 (Mace, 1997). She also did the same for blue marlin and sailfish. These maps are of exquisite detail. They are infinitely finer detail than that produced by Goodyear (1997), and on which NMFS has frequently relied for determining billfish bycatch in U.S. longline fisheries. Mace's maps show exactly where the majority of these fish are being caught throughout the year by longline vessels that are inadvertently "sampling" virtually the entire western North Atlantic Ocean (see Cramer's maps in Appendix 12). When combined with knowledge of the location of the major surface currents and subsurface landform features shown on bathymetric charts (e.g., continental shelf edge, submarine canyons, "banks" and sea mounts), such precise longline catch location data provide a powerful tool in delineating these species' most important habitats, including those of white marlin. Copies of Dr. Mace's map sets (in color) are available from NMFS' HMS Division. The most recent two full years (1994 and 1995) of these maps for all three species are reproduced for illustration in Appendix 8. Also, of great importance in identifying potential critical habitats of white marlin is Dr. F. Arocha's Ph.D. dissertation (1997), copies of which are also available from NMFS' HMS Div. Most instructive is his map showing the primary (known and suspected) spawning, nursery and feeding areas and the migratory pathways of swordfish in the North Atlantic Ocean. This map is reproduced in Appendix 5. What we have come to recognize is that white marlin (and blue marlin) appear to have adopted a nearly identical life cycle strategy as have swordfish.
Examination of these maps shows clearly that white marlin, swordfish, blue marlin and to a lesser degree, sailfish all are found concentrated in generally the same small "hot spots" - that are their critical habitats - at the same time of year each year with predictable occurrence. These "hot spots" change throughout the year as the fish migrate from their spawning grounds in the tropics (occupied during the spring) to their fall feeding grounds at the northern ends of their range, then back again. Most appear to return to the Caribbean along the same major surface current systems which they followed north. However, at least some of the adult swordfish, blue marlin and white marlin appear to follow the major ocean currents in a grand clockwise circle following the North Atlantic Gyre completely around the Sargasso Sea. From recent tagging data (Block et al., 2001) and other sources of information, we believe the same is probably true of western North Atlantic bluefin tuna.
Like salmon returning to the stream where they were spawned, adult white marlin concentrate during the second quarter (April - June) in the large gaps between the major islands of the Caribbean region and in two large areas well east of the Lesser Antilles (or Leeward Islands) along two major oceanic currents (North Equatorial and South Equatorial). As described in the petition, white marlin spawning in the northern hemisphere occurs from March through mid-June, and is apparently centered in the western Bahamas, the Straits of Florida (between Florida and Cuba) and the Greater Antilles including Puerto Rico, according to de Sylva and Breder (1997), Baglin (1979), Mather et al. (1975) and Nakamura (1985). Dr. Mace's maps show additional spawning "hot spots" in the largest channels or passages between the islands of the Caribbean chain, an area south southeast of the U.S. Virgin Islands (but still largely within the U.S. EEZ) and the two very important areas in the Atlantic Ocean well east of the Lesser Antilles (or Leeward Island) chain. Since they are based on U.S. longline vessels' catch, they do not show any catches from the EEZ waters of other nations (especially the Bahamas and Cuba). We believe these "hot spots" are the primary spawning sites and thus are critical habitat for white marlin of the northern hemisphere.
It is also quite possible that such specific spawning sites are used by distinct races of white marlin whose members return annually to these locations, just as do the separate races of salmon (to the specific stream of their origin), with only minimal straying. Thus, there could well be a Florida Straits race of white marlin, a Grand Bahama Bank race, a Yucatan Channel race, a Windward Passage race, etc. The point is that each of these Caribbean area "hot spots" depicted on Dr. Mace's maps and referenced in the literature is a prime spawning site and thus a very important component of this species' critical habitat. In view of the dangerously low population level of white marlin, each of these areas is of even greater importance to the species' survival.
Dr. Arocha's map (Appendix 5) shows that these same white marlin "hot spots" are also prime spawning areas of north Atlantic swordfish, and thus are critical habitat for that northern hemisphere sub-population as well. Dr. Mace's maps show that these same specific sites are also the areas where adult blue marlin are most concentrated during the period when they too are spawning (late spring-early summer, according to de Sylva and Breeder, 1997) in the northern hemisphere. Her maps showing sailfish concentrations indicate that members of this species occupy many of the same "hot spots" although their overall range is much smaller than the larger billfish species. A primary spawning epicenter for sailfish appears to be located in the Florida Straits and lower East Coast of Florida. (Other sailfish spawning epicenters may very well exist along the coast of Central and South America.) From all these maps we can see that most of these same distinct spawning area "hot spots" are critical spawning habitat for not only white marlin but also the other three billfish species. This fact has important management implications because protecting such areas for one species benefits all.
These four billfish species' primary spawning areas are quite small, certainly in relation to the total range of all these highly migratory billfish. They are occupied consistently year after year and at the same time each year by all these species. There are probably slight differences (micro-habitat differences) within the same general spawning site "hot spots" used by these species. For example, sailfish are known to favor shallower habitats (reef fronts) closer to shore than the deep, bluewater areas and current edges preferred by the larger billfish species (according to longliners as relayed by their representative, N. Beideman - personal communication). While swordfish spawn in the same general area, they are thought to spawn at a greater depth in the water column than do white and blue marlin. Presumably, this behavior evolved because it gave swordfish larvae a selective advantage to be in a different layer of the ocean and away from other hungry young billfish (and other predators) that are concentrated near the surface.
As depicted in Dr. Mace's maps (Appendix 8) and the literature cited herein (and in the petition), the primary white marlin spawning site "hot spots" include:
Nursery grounds are probably very much larger in size and much more diffuse than are the white marlin's spawning "hot spots." Nursery grounds would naturally be located "downstream" or down-current from the primary spawning sites. We have much more limited information on the location of the juveniles' nursery areas primarily because white marlin generally do not become vulnerable to longline gear until they reach a weight of about 30 lbs. (NMFS, 1999a).
Apparently, all four billfish species use many of the same areas as their nursery grounds (particularly white marlin, blue marlin and swordfish), possibly because they offer the greatest opportunity for young billfish survival. The coast of Venezuela is well known in sport fishing circles as a site where young white and blue marlin can be found consistently year-round and adults found just before and after the peak of their (spring) spawning season. This probable primary nursery area is located directly "downstream" from one of the two primary spawning areas in the Atlantic Ocean - east of the Lesser Antilles along the edge of the South Equatorial Current and its extension, the Caribbean Current. Other likely white marlin nursery areas are "downstream" from its other primary spawning sites. They would include the northern part of the Caribbean Sea (down-stream from the various passages), the Bahamas, the northern Gulf of Mexico, Florida Straits and the east coast of Florida. These areas are probably the primary nursery grounds for not only white marlin but also blue marlin, swordfish and sailfish. We do know that such areas are important to North Atlantic swordfish. For example, important year-round swordfish nursery grounds are indicated by high year-round catches of small swordfish by longliners along edge of the continental shelf from Florida's Panhandle down to the level of Tampa Bay and from the Straits of Florida up the East Coast of Florida (see maps reproduced in Appendix 12). Young swordfish found in the northeastern Gulf of Mexico likely were spawned in the narrow Yucatan Channel "hot spot" (between Mexico and Cuba) and carried by the Loop Current to their nursery grounds in the northern Gulf of Mexico located off northwest Florida. Swordfish spawned in the Straits of Florida are similarly carried "downstream" by the Florida Current and its extension as the Gulf Stream up the East Coast of Florida to about the level of Charleston, SC. This results in high levels of young swordfish catches by longliners off Charleston (the "Charleston Bump" area) particularly in the fall until winter drives them south again. This same pattern likely holds true for not only swordfish but also white marlin, blue marlin and (to a lesser degree) sailfish. Important nursery areas for white marlin and the other billfish species that lie within the continental U.S. EEZ have also been identified as Essential Fish Habitat in Amendment 1 to the Atlantic Billfish FMP (NMFS, 1999a). All these common nursery grounds are probably used year-round for the first few years of their life by all four billfish species, including white marlin, until they become adults and can withstand the colder temperatures in northern waters where suitable prey is (ordinarily) more abundant.
Prime feeding grounds occupied by white marlin adults during mid-summer and through late fall are located at the northern end of the species' range where their prey is (or was) relatively much more abundant than is the case in the more sterile tropics and sub-tropics. In the Mid-Atlantic region, such areas are important fall feeding "hot spots" because they provide steep drop-offs adjacent to deep water and against which huge eddies (called gyres or "warm-core rings") of the Gulf Stream flow thus creating upwellings (bringing nutrient-rich waters to the surface and fueling an explosion of life) and concentrating vast assemblages of prey species along this edge. Dr. Mace's maps show that white marlin off the U.S. East Coast concentrate during the third quarter of every year in a very narrow band located along the top edge of the continental slope roughly between the 100 fathom (600 ft.) and 1,000 fathom (6,000 ft.) depth contours and extending continuously from the eastern tip of Georges Bank to just south of Cape Hatteras, NC, including the area known as the "Point."
White marlin begin to move up the Atlantic coast immediately following spawning, which peaks in April and May (de Sylva and Breeder, 1997). As can be seen in Dr. Mace's maps (Appendix 8), some adults begin to pass by the Charleston Bump "hot spot" on their way to the long narrow Mid-Atlantic "hot spot" even before the end of the second quarter (April through June). Such concentration points along the route to their fall feeding areas (as indicated in the second quarter maps) should therefore not be confused as spawning areas. There is no advantage in remaining in the spawning grounds after completing spawning since their prey is (or was) more abundant in northern, colder waters than in tropical waters. Thus there would be a selective advantage to migrating north as soon after spawning as possible. Some of these "early arrivals" appear in concentration points toward the northern ends of their range in the second quarter maps from each year.
Other than its spawning sites, the Mid-Atlantic feeding area (on the edge of the continental shelf extending from Cape Hatteras to the eastern end of Georges Bank) appears to be the white marlin's most critical habitat in the northern hemisphere. Its size and location is shown clearly in Dr. Mace's map of the third quarter of 1994 (Appendix 8). The major big game fishing tournaments held each year along the Mid-Atlantic, which are described in the petition, take full advantage of the development of this seasonal "hot spot" for white marlin and the other large pelagic species. White marlin seek out this prime feeding ground as quickly after spawning as possible. They abandon it only when cold temperatures brought on by winter drive them slowly south along the edges of the Gulf Stream and continental shelf toward their Caribbean spawning grounds. They do not re-appear in any numbers in the longliners' catches off the Mid-Atlantic until the second quarter. The same is also true of blue marlin and, to a lesser extent, sailfish.
The same pattern occurs simultaneously in the Gulf of Mexico, as well. The prime feeding grounds are located in the northern Gulf between the 100 and 1,000 fathom depth contours. Three distinct "hot spots" are evident from Dr. Mace's maps (particularly if the full 10 years of longline catch data are considered) - one near the Flower Gardens Banks off Texas, one in the De Soto Canyon area off Pensacola, FL, and one midway between these other two areas off the Mississippi River Delta. White marlin begin to occupy these areas before the end of the second quarter, probably in June and shortly after completing spawning. These three prime feeding areas appear to be occupied continuously from June through at least October. Examining Dr. Mace's maps for all 10 years confirms this same seasonal pattern of use by white marlin as well as by blue marlin and, to a lesser extent, sailfish.
The three Gulf of Mexico "hot spots" and the long Mid-Atlantic "hot spot" are all critical habitat for the white marlin during its feeding period extending from mid-summer through late fall. These areas are particularly important for the females because they must build up stores of energy necessary for the production of millions of eggs by spring. Unfortunately, federal fishery management bodies (NMFS and the Fishery Management Councils) have allowed commercial fishing vessels to severely overfish and thus decimate populations of all the primary prey species of white marlin (as well as the prey of the other large pelagic species of billfish and tunas).
It should be recognized that specific areas along the path of the Gulf Stream and its extensions (the Azores and Canary Currents) in the central and eastern North Atlantic Ocean (see the Atlantic Currents map in Appendix 5) are also probable prime summer through fall feeding grounds for at least a portion of the northern sub-population of white marlin (and blue marlin, swordfish and bluefin tuna) that may be following the "grand circle" route completely around the Sargasso Sea. This "grand circle" route is depicted for a portion of the adult north Atlantic swordfish population by Dr. Arocha, whose map is also reproduced in Appendix 5. Prime big game fishing destinations in the path of these currents include the Azores, Madeira and the Canary Islands. To illustrate the importance of such prime feeding areas to white marlin, this past season a single sportfishing crew (Capri) caught and released 157 white marlin during one 5-day period while fishing on Azores Bank in August of 2001, as reported by angler David Lauzen to the IGFA. According to the IGFA, this may be a record for the most white marlin ever caught by a single angler in a 5-day period. While white marlin are seasonally abundant in the Azores, they are avoided by most sport fishermen who are seeking potential world record-sized blue marlin weighing over 1400 lbs. and (in some years) "grander" bluefin tuna that also concentrate in this prime feeding area. Using larger lures trolled at greater speed (above 8 knots) maximizes chances of attracting and catching the much larger blue marlin and minimizes hookups of white marlin. This fact also has important management implications as it provides a means to minimize the catch and potential harm to white marlin by billfish anglers.
Migration routes of white marlin are also among its critical habitats. Based on their observed preference for the edges of major oceanic surface currents, as described previously, and records of their catch by U.S. longliners and in the international billfish sportfisheries, we suggest that the primary migration routes of the northern hemisphere's sub-population of white marlin include: the Gulf Stream (particularly its shoreward or western edge and its warm-core gyres), the Florida Current, the Loop Current (particularly its shoreward edge and gyres), the Caribbean Current (particularly its shoreward or southern edge), the Puerto Rico Current, the Antilles Current, the South Equatorial Current, the North Equatorial Current, the Canary Current and the Azores Current. The major surface currents of the North Atlantic Ocean are shown on the map in Appendix 5.
Of all these ecologically critical habitats - for spawning, nursery, feeding and migration - those located within the U.S. EEZ (including the Caribbean) should also be designated "Essential Fish Habitat" (EFH) within the meaning of the Magnuson-Stevens Act. (EFH has been interpreted by the U.S. government as being limited to only those waters within the U.S. EEZ boundary.)
Primary Source of White Marlin Mortality
Based on the SCRS's most recent statistics as documented in the petition, commercial fishing vessels from many nations are responsible for 99.89 percent of the reported Atlantic-wide mortality of Atlantic white marlin. The international recreational fishing community (which voluntarily releases roughly 99 percent of its billfish catch) is responsible for the remainder (0.11 percent). Of the commercial mortality, longlines are responsible for 92 percent. Therefore, it is clear as to which sector and which gear-type needs to substantially reduce its mortality if white marlin are to be saved from extinction. The most recent ICCAT recommendation (Annex 7-13) calls for the release of all live billfish at the vessel. This is a very good step, but it may come too late to save white marlin, for the following reasons. First, it did not go into effect until June 1, 2001, or two years after the last stock assessment (1999) meaning two years of additional mortality has occurred. At the end of 1999, total Atlantic stock's biomass had rapidly declined to just 13 percent of its sustainable level (MSY) and the fishing mortality rate had risen dramatically to eight times the sustainable rate. At its rate of decline in abundance due to this excessive level of overfishing, the biomass of Atlantic white marlin could be expected to intersect the zero line within five years.
It is known that approximately 30 percent of the white marlin (and 25 percent of blue marlin) caught on longlines come to the boat dead. This means that if ICCAT's new recommendation are followed by every ICCAT member (many members routinely ignore ICCAT recommendations for quotas and minimum size limits), the rate of mortality could be reduced by no more than 70 percent. Thus, the mortality rate could at most be reduced from eight times the sustainable level to 2.4 times the sustainable level. This is still more than double the sustainable rate of fishing mortality. At best, this reduction in fishing pressure will slow but not halt the population's slide toward extinction. The only way to eliminate this remaining mortality is to prevent commercial vessels from fishing in the white marlin's critical habitats where 30 percent of those caught will continue to come to the boat dead.
In view of the extremely low biomass level and its continued steep rate of decline, as projected by the SCRS (SCRS/00/23), additional steps are needed. We recommend that the U.S. government immediately seek international agreement (at ICCAT) to prohibit longlines and other commercial vessels from fishing in the white marlin's primary spawning area "hot spots" in both hemispheres. To set a good example and to reduce the interception and kill of white marlin by U.S. longline vessels by approximately 85 percent, we also recommend that the action recommended below be taken by the U.S. in its waters.
All commercial fishing affecting white marlin need not be halted, only that causing the bulk of the problem and then, only in their key habitats. Aggressive U.S. leadership is urgently needed now to address the problem. Without such U.S. leadership, reliance on ICCAT member nations to conserve the species is an illusion. The United States must take the lead by reducing the major sources of white marlin bycatch mortality within the U.S. EEZ and by immediately seeking international agreements (1) to reduce overall fishing mortality to levels that will stop the decline and ensure a recovery, and (2) to close at least their prime spawning areas to commercial fishing.
Critical Habitat in U.S. EEZ Waters Needing Protection
Pelagic longline bycatch accounts for more than 98 percent of reported U.S.-caused white marlin mortality (SCRS/00/23, Table 2). However, the U.S. government has done nothing to significantly reduce the bycatch of this extremely overfished species despite the clear direction of the Magnuson-Stevens Act to minimize bycatch and the mortality of bycatch that can not be avoided to the extent practicable. As a consequence, indiscriminant longline fishing continues to drive this population ever closer toward extinction.
Bycatch mortality is occurring primarily in this species' key spawning and feeding areas - the "hot spots" referred to earlier. Specified below are those located within the U.S. EEZ that should be closed to commercial fishing for HMS. They are all clearly depicted on Dr. Mace's maps. The total area contained within these "hot spots" is less than 2 percent of the total area fished predominantly by the U.S. longline fleet (see Appendix 12). Consequently, their closure will not affect a large portion of the ocean areas fished by longliners - only that portion which is the most important to white marlin. Reducing bycatch in the primary U.S. EEZ "hot spots" will significantly reduce fishing mortality on white marlin over a large percentage of their most important habitats. This will contribute very substantially to the population's recovery. The relative amount of bycatch reduction possible by closing these 'hot spots" could be quantified readily by using the GIS maps prepared by NMFS' Dr. Pamela Mace based on U.S. longline logbook data for 1994 and 1995 (Appendix 8, White Marlin, Quarters 2 and 3). A rough approximation is that more than 85 percent of the white marlin interception and kill would be eliminated by adopting the seasonal longline closure areas in U.S waters recommended below. Applying 85 percent mortality reduction to the 3,658 white marlin that NMFS estimates were killed by U.S. longline vessels in 1995 (Cramer and Adams, 1999), would eliminate the deaths of over 3,100 white marlin per year. It would do so by affecting only about 2 percent of the U.S. longline vessels' normal fishing area. It is certainly time for the commercial sector to start shouldering some of the load of conservation that until now has been borne by the recreational sector. It has established a very high standard for the commercial sector by reducing its mortality to a handful of white marlin per year - eight fish reported killed in the latest year (2000).
If there are actually two separate sub-populations of Atlantic white marlin (i.e., a North and a South Atlantic population), which is clear to us as discussed in detail in the petition, this recommended U.S. action will have a profound effect on the recovery of the northern sub-population. Therefore, the societal and economic benefits of the northern sub-population's recovery will flow largely to the U.S. and the nations of the broader Caribbean region.
From tagging returns and 11 years of detailed catch history data from U.S. longline vessels (as mapped by Dr. Mace), we know that this sub-population spends a majority of its life history in U.S waters and those of our neighbors to the south in the Caribbean region. Dr. Mace's maps make this point very well. It is confirmed by years of tagging returns. Except for occasional strays, tagging returns show that the range of the northern white marlin sub-population does not overlap that of the southern hemisphere's sub-population. Of the 41,177 northern hemisphere white marlin that have been tagged, not one has been recovered in the southern hemisphere. The epicenters of the two hemispheres' spawning areas are separated by 5,000 miles. Moreover, they are used during the spring in each hemisphere thus occupied six months apart. White marlin in the North Atlantic Ocean are concentrated along the mid-Atlantic and northern Gulf of Mexico "hot spots" in our fall when the white marlin of the South Atlantic Ocean are moving toward the coast of central Brazil (specifically the Royal Charlotte Bank area) in preparation for their spawning in that hemisphere's spring.
The United States has the authority to independently protect key habitats (i.e., spawning areas and important feeding areas) in its EEZ waters. ATCA, the federal statute authorizing U.S. implementation of ICCAT's recommendations, does not prevent complementary conservation action in U.S. waters. In particular, there is no prohibition against closing any areas to U.S. fishing vessels as a means to assist in conserving and rebuilding a population. In fact, ICCAT has recommended the use of area closures to protect important habitats, and NMFS has recently closed several areas to reduce longline bycatch of very small (sub-legal) swordfish.
The United States has a duty to properly manage fishing in its own waters to help conserve Atlantic white marlin. U.S commercial fishing vessels should be prohibited from using non-selective gear in white marlin "hot spots" located in U.S. EEZ waters (see below and Appendix 8), and existing closures should be continued. (This will also provide a good example for the international community to follow, which is a prerequisite for seeking further international reductions in mortality.) Therefore, the United States should immediately take the necessary steps to prohibit commercial vessels from fishing for any large pelagic species in the critical habitats of white marlin which are located in the U.S. EEZ.
By region, the portion of the critical habitat of Atlantic white marlin, which is located within U.S. EEZ waters, is as follows:
Northeast To protect white marlin, blue marlin and bigeye tuna, prohibit the use of longlines in the U.S. EEZ along the Continental Slope from the 100 fathom contour out to the 1,000 fathom contour between the eastern tip of Georges Bank (66° 10' W long.) to Cape Hatteras (35° N lat.) from June through October.
Southeast To protect blue marlin, sailfish, white marlin and juvenile swordfish, prohibit the use of longlines in the U.S. EEZ along the Continental Slope from the 100 fathom contour out to the 1,000 fathom contour between Cape Hatteras (35° N lat.) and Cape Canaveral (29° N lat.) from March through November.
Florida East Coast To protect blue marlin, sailfish, white marlin, bluefin tuna and juvenile swordfish, prohibit the use of longlines in the U.S. EEZ along the Continental Slope from the 100 fathom contour out to the 1,000 fathom contour or the edge of the U.S. EEZ from Cape Canaveral (29° N lat.) through the Straits of Florida (to 82° W long.), year-round.
Gulf of Mexico To protect blue marlin, sailfish, white marlin, bluefin tuna and juvenile swordfish, prohibit the use of longlines in the U.S. EEZ along the Continental Slope from the 100 fathom contour out to the 1,000 fathom contour from the Straits of Florida (82° W long.) to the border between the United States and Mexico (26° N lat.) year-round.
Caribbean Sea To protect a key spawning (and nursery) area of swordfish, blue marlin, white marlin and sailfish, prohibit the use of longlines in the U.S. EEZ east of 65° 30' W long. and along the Continental Slope from the 100 fathom contour out to the 1,000 fathom contour surrounding Puerto Rico and the U.S. Virgin Islands on a year-round basis.
Many consider white marlin to be the perfect gamefish. It is fast, powerful, very acrobatic and reaches 200 pounds in weight. It is central to most Atlantic billfish tournaments. As noted in our petition, with about 400 big game fishing tournaments held each year, many fishing "destinations" already documented as contributing tens of millions of dollars in annual regional economic activity (there are an estimated 230,000 billfish anglers in the U.S. who spend an estimated $2.13 billion annually on fishing, as documented by Ditton, 2000, and ASA, 1997), and big game fishing (almost totally catch and release) already large and growing in popularity, the species is simply too valuable to lose. Therefore, we expect NMFS to act as its steward by promptly designating and taking action to protect its critical habitats, particularly the identified "hot spots."
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Mace, P.M. 1997c. A series of maps showing the occurrence of blue marlin, white marlin, an sailfish in the catch of the U.S. pelagic longline fishery during 1986-1996 based on longline operators’ logbook reports and developed using GIS mapping techniques (ArcInfo and ArcView). National Marine Fisheries Service, Woods Hole, MA.
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SCRS. 2000. Report of the Fourth ICCAT Billfish Workshop (Miami, F1orida, USA, July 18-28, 2000) - Billfish Detailed Report (SCRS/00/23). Standing Committee on Research and Statistics, International Commission for the Conservation of Atlantic Tunas.
Annex 7-13 Recommendation by ICCAT to establish a plan to rebuild blue marlin and white marlin populations.