Abstract Pop-up satellite archival tags (n = 31) were deployed on Yellowfin Tuna Thunnus albacares in the Gulf of Mexico for periods ranging from 14 to 95 d. Differences in diel vertical behavior were assessed by comparing time spent at temperature relative to the surface temperature (ΔT). Pooled samples revealed that 31% of darkness hours, 20% of twilight hours, and 12% of daylight hours were spent in the uniform-temperature surface layer (i.e., ΔT = 0). Total time spent above 100 m was less during daylight (90.0%) than during darkness (99.8%), suggesting greater exploration of deeper depths during daylight hours. Maximum depth visited ranged from 208 to 984 m, and minimum temperature visited ranged from 5.4°C to 11.8°C. Only a small proportion of total time was spent at temperatures colder than 8°C below the surface temperature. Horizontal excursions for the majority of individuals were less than 100 km from the point of release; however, three individuals moved distances of 411–1,124 km, suggesting that this species has the capability to move relatively long distances within the Gulf of Mexico. The ΔT values are provided in tabular format and serve as direct input variables for use in habitat standardization models.

In June 2003, fisheries research was conducted in the Windward Passage using a chartered commercial pelagic longline vessel (Rice and Snodgrass 2003). This paper describes the habitat use by an escolar in this location tagged with a pop-up satellite archival tag (PSAT) that remained attached to the fish for 14 d. Data recovered from the PSAT were used to directly document diel vertical migration and ambient temperature range for the first time in a mesopelagic teleost.

Journal of Applied IchthyologyVolume 23, Issue 2 p. 184-188 Tracking gender factors in fish surface mucus: temporal patterns in individual Koi (Cyprinus carpio) D. R. Schultz, D. R. Schultz Department of Medicine, University of Miami School of MedicineSearch for more papers by this authorN. Perez, N. Perez Department of Medicine, University of Miami School of MedicineSearch for more papers by this authorA. J. Mendez, A. J. Mendez Clinical Chemistry Laboratory, Diabetes Research Institute, University of Miami School of MedicineSearch for more papers by this authorD. Snodgrass, D. Snodgrass Southeast Fisheries Science Center, National Marine Fisheries Service, Miami, FLSearch for more papers by this authorJ. E. Serafy, J. E. Serafy Southeast Fisheries Science Center, National Marine Fisheries Service, Miami, FLSearch for more papers by this authorE. D. Prince, E. D. Prince Southeast Fisheries Science Center, National Marine Fisheries Service, Miami, FLSearch for more papers by this authorW. A. Crow Jr, W. A. Crow Jr Department of Medicine, University of Miami School of MedicineSearch for more papers by this authorT. R. Capo, T. R. Capo Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USASearch for more papers by this author D. R. Schultz, D. R. Schultz Department of Medicine, University of Miami School of MedicineSearch for more papers by this authorN. Perez, N. Perez Department of Medicine, University of Miami School of MedicineSearch for more papers by this authorA. J. Mendez, A. J. Mendez Clinical Chemistry Laboratory, Diabetes Research Institute, University of Miami School of MedicineSearch for more papers by this authorD. Snodgrass, D. Snodgrass Southeast Fisheries Science Center, National Marine Fisheries Service, Miami, FLSearch for more papers by this authorJ. E. Serafy, J. E. Serafy Southeast Fisheries Science Center, National Marine Fisheries Service, Miami, FLSearch for more papers by this authorE. D. Prince, E. D. Prince Southeast Fisheries Science Center, National Marine Fisheries Service, Miami, FLSearch for more papers by this authorW. A. Crow Jr, W. A. Crow Jr Department of Medicine, University of Miami School of MedicineSearch for more papers by this authorT. R. Capo, T. R. Capo Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USASearch for more papers by this author First published: 31 January 2007 https://doi.org/10.1111/j.1439-0426.2006.00799.xCitations: 7 Author's address: D. R. Schultz, Department of Medicine, University of Miami School of Medicine, R-102, PO Box 016960, Miami, FL 33101, USA.E-mail: [email protected] Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL References Barbieri, L. R.; Chittenden, M. E. Jr; Lowerre-Barbieri, S. K., 1994: Maturity, spawning, and ovarian cycle of Atlantic croaker, Micropogonias undulatus, in the Chesapeake Bay and adjacent coastal waters. US Fish. Bull. 92, 671– 685. Barry, T. P.; Santos, A. J. G.; Furukawa, K.; Aida, K.; Hanyu, I., 1990: Steroid profiles during spawning in male common carp. Gen. Comp. 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R., 1996: Reconnaissance of 17 ß-estradiol, 11-ketotestosterone, vitellogenin, and gonad histopathology in common carp of United States Streams: potential for contaminant-induced endocrine disruption. USGS-Pesticide National Synthesis Project Pesticides Report. US Geological Survey Open-File Report 96–627, USGS, Denver, CO. Goodwin, A. E.; Grizzle, J. M.; Bradley, J. T.; Estridge, B. H., 1992: Monoclonal antibody-based immunoassay of vitellogenin in the blood of male channel catfish (Ictalurus punctatus). Comp. Biochem. Physiol. 101B, 441– 446. Gordon, M. P.; Owen, T. G.; Ternan, T. A.; Hildbrand, L. K., 1984: Measurement of a sex-specific protein in skin mucus of premature coho salmon (Oncorynchus kisutch). Aquaculture 43, 333– 339. Grier, H. J., 2002: The germinal epithelium: its dual role in establishing male reproductive classes and understanding the basis for indeterminate egg production in female fishes. Proc. Gulf Carib. Fish. Inst. 53, 537– 552. Kime, D. E.; Nash, J. P.; Scott, A. P., 1999: Vitellogenesis as a biomarker of reproductive disruption by xenobiotics. Aquaculture 177, 345– 352. Kishida, M.; Anderson, T. R.; Specker, J. L., 1992: Induction of vitellogenin in striped bass (Morone saxatilis): characterization and quantification in plasma and mucus. Gen. Comp. Endocrinol. 88, 29– 39. Laemmi, U. K., 1970: Cleavage of structural proteins during the assembly of the head of the bacteriophage T4. Nature 227, 680– 685. Leatherland, J. F.; Copeland, P.; Sumpter, J. P.; Sonstegard, R. A., 1982: Hormonal control of gonadal maturation and development of secondary sexual characteristics in coho salmon, Oncorhynchus kisutch, from Lakes Ontario, Erie and Michigan. Gen. Comp. Endocrinol. 48, 196– 204. Lokman, P. M.; Vermeulen, G. J.; Lambert, J. G. D.; Young, G., 1998: Gonad histology and plasma steroid profiles in wild New Zealand freshwater eels (Anguilla dieffenbachia and A. australis) before and after onset of the natural spawning migration. I. Females. Fish Physiol. Biochem. 19, 325– 338. Lowerre-Barbieri, S. K.; Chittenden, M. E., Jr; Barbieri, L. R., 1996: The multiple spawning patterns of weakfish, Cynoscion regalis, in the Chesapeake Bay and Middle Atlantic Bight. J. Fish. Biol. 48, 1139– 1163. Mommsen, P. T.; Walsh, P., 1988: Vitellogenesis and oocyte assembly. In: Fish physiology, Vol. 11A. W. S. Hoar, D. J. Randall and E. M. Donaldson (Eds). Academic Press, New York, pp. 347– 406. Moncaut, N.; Nostro, F.; Maggese, M. C., 2003: Vitellogenin detection in surface mucus of the South American cichlid fish Cichlasoma dimerus (Heckel, 1840) induced by estradiol-17ß. Effects on liver and gonads. Aquat. Toxicol. 63, 127– 137. Schultz, D. R.; Perez, N.; Tan, C.-K.; Mendez, A. J.; Capo, T. R.; Snodgrass, D.; Prince, E. D.; Serafy, J. E., 2005: Concurrent levels of 11-ketotestosterone in fish surface mucus, muscle tissue and blood. J. Appl. Ichthyol. 21, 394– 398. Slater, C. H.; Schreck, C. B.; Swanson, P., 1994: Plasma profiles of the sex steroids and gonadotropins in maturing female spring Chinook salmon (Oncorhynchus tshawytscha). Comp. Biochem. Physiol. 109A, 167– 175. Sumpter, J. P., 1991: The purification, radioimmunoassay and plasma levels of vitellogenin from the rainbow trout, Salmo gairdneri. In: Current trends in comparative endocrinology, Vol. 1. B. Lofts and W. N. Holmes (Eds). Hong Kong University Press, Hong Kong, pp., 355– 357. Tan, C.-K.; Perez, N.; Mendez, A. J.; Snodgrass, D.; Prince, E. D.; Serafy, J. E.; Arocha, F.; Schultz, D. R., 2006: Identification of vitellogenic Atlantic blue marlin (Makaira nigricans) from muscle samples using an ELISA for vitellogenin-derived yolk proteins. Bull. Mar. Sci., 78, 319– 329. Towbin, H.; Staelin, T.; Gordon, J., 1979: Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications. Proc. Natl Acad. Sci. USA 76, 4350– 4354. Wiegand, M. D., 1996: Composition, accumulation and utilization of yolk lipids in teleost fish. Rev. Fish Biol. Fish. 6, 259– 286. Citing Literature Volume23, Issue2April 2007Pages 184-188 ReferencesRelatedInformation

This study evaluates the performance of two types of non-offset circle hooks (traditional and non-traditional) and a similar-sized 'J' hook commonly used in the south Florida recreational live-bait fishery for Atlantic sailfish, Isiophorus platypterus (Shaw). A total of 766 sailfish were caught off south Florida (Jupiter to Key West, FL, USA) to assess hook performance and drop-back time, which is the interval between the fish's initial strike and exertion of pressure by the fisher to engage the hook. Four drop-back intervals were examined (0-5, 6-10, 11-15 and > 15 s), and hook performance was assessed in terms of proportions of Successful catch, undesirable hook locations, bleeding events and undesirable release condition associated with physical hook damage and trauma. In terms of hook performance, the traditionally-shaped circle hook had the greatest conservation benefit for survival after release. In addition, this was the only hook type tested that performed well during each drop-back interval for all performance metrics. Conversely, 'J' hooks resulted in higher proportions of undesirable hook locations (as much as twofold), bleeding and fish released in undesirable condition, particularly during long drop-back intervals. Non-traditional circle hooks had performance results intermediate to the other hook types, but also had the worst performance relative to undesirable release condition during the first two drop-back intervals. Choice of hook type and drop-back interval can significantly change hook wounding, and different models of non-offset circle hooks should not be assumed to perform equivalently.

The purpose of this study was to develop a direct sandwich enzyme-linked immunosorbent assay (ELISA) for vitellogenin-derived yolk proteins (VDYP) in muscle tissue of pelagic Atlantic blue marlin. Gravid ovaries were extracted with physiologic buffer, and purification steps by chromatography were monitored with a cross-reactive mouse monoclonal antibody produced to swordfish (Xiphias gladius Linnaeus, 1758) VDYP. A polyclonal goat antiserum was produced to the enriched VDYP from which specific IgG was purified by affinity chromatography, using immobilized VDYP as the immunoadsorbent. A direct sandwich ELISA was developed using the purified IgG for both capture and detection of the VDYP in standard samples up to a concentration of 1000 ng/ml, and in physiologic buffer-extracted muscle tissue of test samples, using biotin-streptavidin-peroxidase technology. The assay distinguished vitellogenic from non-vitellogenic females and males in extracts of muscle tissue from 27 specimens collected from different areas of the western North Atlantic Ocean during May-September, 2002-2003. The assay for VDYP, and a second for the fish androgen 11-ketotestosterone are in use to indicate gender of electronically-tagged blue marlin from biopsy samples taken just before fish release.

A quantitative framework and numerical methodology were developed to characterize vertical habitat utilization by large pelagic animals and to estimate the probability of their capture by certain types of fishing gear. Described are the steps involved to build 'vertical habitat envelopes' from data recovered from an electronically tagged blue marlin (Makaira nigricans) as well as from a longline fishing gear experiment employing temperature-depth recording devices. The resulting vertical habitat envelopes, which integrate depth and temperature preferences of tagged fish, are conducive for comparative studies of animal behavior and for calculation (and visualization) of degrees of overlap - be it among individuals, species or fishing gear. Results of a computer simulation evaluation indicated our numerical procedure to be reliable for estimating vertical habitat use from data summaries. The approach appears to have utility for examining pelagic longline fishing impacts on both target and non-target species and could point to ways of reducing bycatch via modification of fishing strategy or gear configuration.

With a focus on white marlin (Tetrapturus albidus), a concurrent electronic tagging and larval sampling effort was conducted in the vicinity of Mona Passage (off southeast Hispaniola), Dominican Republic, during April and May 2003. Objectives were 1) to characterize the horizontal and vertical movement of adults captured from the area by using pop-up satellite archival tags (PSATs); and 2) by means of larval sampling, to investigate whether fish were reproducing. Trolling from a sportfishing vessel yielded eight adult white marlin and one blue marlin (Makaira nigricans); PSAT tags were deployed on all but one of these individuals. The exception was a female white marlin that was unsuitable for tagging because of injury; the reproductive state of its ovaries was examined histologically. Seven of the PSATs reported data summaries for water depth, temperature, and light levels measured every minute for periods ranging from 28 to 40 days. Displacement of marlin from the location of release to the point of tag pop-up ranged from 3l.6 to 267.7 nautical miles (nmi) and a mean displacement was 3.4 nmi per day for white marlin. White and blue marlin mean daily displacements appeared constrained compared to the results of other marlin PSAT tagging studies. White marlin ovarian sections contained postovulatory follicles and final maturation-stage oocytes, which indicated recent and imminent spawning. Neuston tows (n=23) yielded 18 istiophorid larvae: eight were white marlin, four were blue marlin, and six could not be identified to species. We speculate that the constrained movement patterns of adults may be linked to reproductive activity for both marlin species, and, if true, these movement patterns may have several implications for management. Protection of the potentially important white marlin spawning ground near Mona Passage seems warranted, at least until further studies can be conducted on the temporal and spatial extent of reproduction and associated adult movement.

A rapid, reproducible method is described for extracting and comparing levels of the ether-soluble fish androgen 11-ketotestosterone (11-KT) in blood serum, muscle tissue and surface mucus. Because widely different volumes of extract were recovered after centrifugation from the three sources, it was important to express androgen levels as pg 11-KT/mg of total soluble protein (TSP). For six male and four female sexually-staged freshwater Koi (Cyprinus carpio), the method yielded similar pg 11-KT/mg TSP ratios in blood serum and extracts of muscle tissue and surface mucus, with the strongest correlation between blood serum and surface mucus. While male Koi were distinguishable from females based on the magnitude of 11-KT levels, reproductive stage and gonadosomatic index levels were not correlated with the 11-KT levels of either sex. Similar pg 11-KT/mg TSP ratios were also found for autologous muscle tissue and surface mucus extracts of 37 captured and sexed wild marine fishes representing seven genera. However, high 11-KT levels were not restricted to mature males. Collectively, results suggest that surface mucus collection (followed by 11-KT assay) is a useful alternative to more invasive methods of determining systemic hormone levels in fish. Without knowledge of seasonal variation in levels of this and other sex hormones, however, reliance on 11-KT levels alone may lead to spurious identification of gender, let alone reproductive stage.

Blue marlin (Makaira nigricans) sup(MSY) and that current harvests are port commercial and recreational more than twice the replacement yield, fisheries throughout the tropical and further contributing to the decline of subtropical waters of the Atlantic the stock (ICCAT, 2001). A reduction in Ocean. The species is taken in directed fishing mortality of approximately 60% recreational and artisanal fisheries is needed simply to halt the decline in in several areas and constitutes an stock abundance (Goodyear, 2000). incidental catch of the widespread One means of reducing fishing mor­ commercial pelagic longline fishery. tality on blue marlin, without severely Although blue marlin comprise only a impacting catches of target species of small fraction of the catch of the pelathe pelagic longline fishery, is to release gic longline fishery that targets tunas those blue marlin that are alive at the and swordfish, this fishery accounts time longline gear is retrieved (hauled for the majority of fishing mortality back). Jackson and Farber (1998) reon Atlantic blue marlin (ICCAT, 1997; ported that 48% of blue marlin caught 2001). in the Venezuelan longline fishery are Atlantic blue marlin were last asalive at the time of haulback. Data from sessed in 2000 by the Standing Committhe U.S. observer program between tee for Research and Statistics (SCRS) 1992 and 1996 indicate that 66% of of the International Commission for the blue marlin were released alive from Conservation of Atlantic Tunas (ICthe domestic longline fishery (Lee and CAT). The assessment indicated that Brown, 1998) and U.S. National Marine the total biomass of Atlantic blue marFisheries Service (NMFS) data and lin is only about 40% of that necessary mandatory pelagic longline logbook to produce maximum sustainable yield submissions between 1987 and 1991 indicate that 59.8% of blue marlin are released alive from commercial pelagic longline gear (Cramer, 1998). ICCAT has been encouraging the release of live blue marlin for several years, and in 2000 the Commission mandated that all live blue marlin and white marlin be released from com­ mercial longline and purse seine ves­ sels. However, for such a management measure to significantly reduce fishing mortality, released animals must have a reasonably high postrelease survival rate. Little information exists about postrelease survival of blue marlin, espe­ cially of animals taken on pelagic longline gear. In general, recovery rates of billfish tagged with conventional (streamer) tags have been quite low (<2%; Jones and Prince, 1998; Ortiz et al., 1998). This observation is consis­ tent with high postrelease mortality, although low recovery rates could also result from tag shedding and a lack of reporting recovered tags (Bayley and Prince, 1994; Jones and Prince, 1998). Results of acoustic tracking studies of blue marlin captured on recreational gear suggest that postrelease survival over periods of a few hours to a few days is relatively high, although mortalities have been noted (reviewed in Pepperell and Davis, 1999). More recently, popup satellite archival tags (PSATs) have been used to study postrelease survival of blue marlin taken in a recreational fishery. Graves et al. (2002) attached nine PSATs to blue marlin caught on recreational gear off Bermuda. Eight of the tags detached from the animals and reported as expected after five days; net displacement and direction, tag incli­ nation, and temperature data for all eight individuals were consistent with postrelease survival for five days. In this note, we present the results of a study evaluating the postrelease survival of blue marlin from pelagic longline fishing gear in the western North Atlantic. We include analyses of the movement and behavior of these animals for tagging periods of both five days and thirty days.

We describe a two-phased project that examines "essential fish habitat" for blue marlin, Makaira nigricans. It builds on previous work and constitutes an international cooperative research effort involving government and university scientists and recreational and commercial fishers. Neuston sampling during July 2000 and July 2001 in the vicinity of Exuma Sound, Bahamas, yielded some of the highest densities of circa 2 - 17 day old blue marlin larvae ever reported. This indicates that the waters directly upstream of the Sound served. as blue marlin spawning grounds and that the Sound itself may be an important nursery area, at least during the summer. These results have prompted implementation of the second phase of the project: "pop-up" satellite tagging of adults at locations both upstream and downstream of the Sound during the peak of the next spawning season (i.e., June, 2002) followed by additional, larval sampling in the vicinity of the Sound during July, 2002. This work may provide valuable insight into the nursery role of Exuma Sound relative to open-ocean environments as well as into the extent of adult movement during the peak l of their spawning period. Concurrent with our work are three other studies that will complement our research:i) An effort to combine genetic and traditional methods for identifying even badly damaged billfish larvae to species;ii) An effort to age larval blue marlin from their otoliths; andiii) An effort to determine the sex and reproductive status of tagged adults from a small sample of muscle tissue.Collectively, these ongoing investigations may provide critical information for the protection of spawning and nursery habitats for Atlantic blue marlin and possibly other billfishes in the region. A future application for this work, if the study is expanded spatially and a time series is developed, is to assess whether abundances of larval blue marlin can be used as a fishery-independent index of spawning stock biomass.

Release and recovery files from the world's five major constituent-based billfish (Istiophoridae) tagging programs were assembled into a single composite database. Data sources included the National Marine Fisheries Service's (NMFS) Cooperative Tagging Center (MIA) in the Atlantic Ocean, the NMFS's Cooperative Billfish Tagging Program (LJA) in the Pacific and Indian Oceans, the Australian Cooperative Tagging Program in the Pacific and Indian Oceans, the New Zealand Cooperative Game Fish Tagging Program in the Pacific Ocean, and The Billfish Foundation's (TBF) tagging program in the Atlantic, Pacific and Indian Oceans. Results for the main target species, including black marlin (Makaira indica), blue marlin (Makaira nigricans), white marlin (Tetrapturus albidus), striped marlin (Tetrapturus audax) and sailfish (Istiophorus platypterus) were compared and contrasted based on species, ocean body and tagging program. A total of over 317 000 billfish have been tagged and released, and 4122 have been recovered since 1954. Tag recovery percentages were generally higher for a recently developed double-barb nylon anchor tag compared with the typically used stainless steel dart tag. Greatest distances moved were largest for blue marlin and black marlin, followed by striped marlin, white marlin and sailfish. The TBF program had the highest tag recovery percentages for white marlin (2.4%) and blue marlin (1.7%), whereas the MIA program had the highest percentage recovery for sailfish (1.8%). The LJA program had the highest recovery percentages for black marlin (1.9%) and striped marlin (1.4%). The annual number of releases and recoveries for each target species tended to increase over the time series, particularly during the last decade. Cyclic annual movement patterns and/or seasonal site fidelity were evident for black marlin and white marlin. The data suggest that tag recovery percentages can be affected by tag type, reporting rate, localized fishing activities, outreach activities, and a variety of logistical issues indirectly related to size of ocean body. The efficiencies of the tagging programs are compared and recommendations are made to improve the programs. The composite tagging database provides the opportunity for a more comprehensive evaluation of the data and tagging programs than has previously been possible by examining the individual programs in isolation. The main advantage of constituent-based tagging programs is that large numbers of billfish can be tagged at a minimum cost. The main drawbacks are a lack of control over the tagging event and return of recovery data. Constituent-based tagging programs provide essential data on billfish movement and biology, and should be expanded and improved to meet the increasing need for this information.

The Cooperative Tagging Center (CTC) of the National Marine Fisheries Service's Southeast Fish- eries Science Center operates one of the largest and oldest fish tagging programs of its type in the world. Since 1954, more than 35,000 recreational and commercial fishing constituents have voluntarily participated in the CTC, and this has resulted in tagging more than 245,000 fish of 123 species. Although some tagging activities have been conducted by scientists, most of the tag release and recovery activities were achieved by recreational and commercial fishery constituents. Five large highly migratory species have historically represented the Program's primary target species, including Atlantic bluefin tuna Thunnus thynnus, blue marlin Makaira nigricans, white marlin Tetrapturus albidus, sailfish Istiophorus platypterus, and broadbill swordfish Xiphias gladius. Tagging equipment and procedures for catching, tagging, and resuscitation of species too large to be brought aboard fish- ing vessels have evolved and improved considerably over the years. This paper presents a review of the devel- opment of the most efficient tagging, handling, and dehooking techniques used on a variety of large highly migratory species in the CTC. In addition, the results of a comparative tag retention study on billfish are presented, com- paring stainless steel dart tags used for nearly 30 years with a hydroscopic nylon double-barb dart tag, recently developed in conjunction with The Billfish Foundation. Recommendations are made on the best techniques, pro- cedures, and equipment for in-water tagging of large, highly migratory species.

This study evaluates the performance of circle and comparable-size "J" hooks on Atlantic and Pacific sailfish Istiophorus platypterus and, to a lesser extent, on Pacific blue marlin Makaira nigricans. Terminal gear performances were assessed in terms of fishing success. hook location, and bleeding associated with physical hook damage and trauma. Evaluations of trolling with dead bait took place off Iztapa, Guatemala, during the spring and summer of 1999, and assessment of drifting/kite fishing with live bait took place Off South Florida during the summer of 1999.Three hundred and sixty Pacific sailfish were caught in Iztapa, Guatemala, to assess terminal gear performance; 235 sailfish were on circle hooks, and 125 were on "J" hooks. Circle hooks used on sailfish bad hooking percentages (i.e., fish hooked/fish bite) that were 1.83 times higher compared with "J" hooks. Once the fish were hooked, no difference in catch percentage (i.e., fish caught/fish hooked) between hook types was detected. Significantly more sailfish were hooked in the corner of the Mouth using circle hooks (85%). as compared with "J" hooks (27%). In contrast, significantly more sailfish were deep hooked in the throat and stomach with "J" hooks (46%), as compared with circle hooks (2%). Only one sailfish (1%) was foul hooked using circle hooks. while 11 (9%) sailfish caught on "J" hooks were foul hooked. Sailfish caught on "J" hooks are 21 times more likely to suffer hook-related bleeding than those caught on circle hooks.Seventy-five Atlantic sailfish were caught using circle hooks in the South Florida live bait recreational fishery to assess possible differences in hook performance between circle hooks with and without an offset point. No difference in catch percentage or bleeding was found between circle hooks with no offset, minor offset (about 4 degrees), or severe offset points (about 15 degrees). However, the percentage of deep hooking in the throat and stomach for circle hooks with a severe offset (44%) was comparable to the deep hooking percentage for "J" hooks (46%) used in the Guatemala study. A comparison of circle and "J" hook catch rates of Pacific sailfish and blue marlin, using logbook catch statistics from recreational fishing off Iztapa, Guatemala, was also conducted. In general, use of circle hooks resulted in measures of fishing success that were comparable to or higher than "J" hooks. Circle hooks also minimized deep hooking, foul hooking, and bleeding. Thus, the use of circle hooks has con-(sic).

Because commercially caught billfishes are usually processed at sea. and because size measurements are usually taken after the fish have been dressed, there is a need for conversion among different measures of size (length or weight) for assessment and management purposes. Here, we present empirical equations for converting among measures of size for blue marlin, Makaira nigricans; white marlin, Tetrapturus albidus; and sailfish, Istiophorus platypterus, from the North Atlantic Ocean. A series of length-length equations allows conversion from any of six length measures to lower jaw-fork length; and a series of length-weight and weight-length equations allow conversion between lower jaw-fork length and round weight. To estimate the equations, we used large data sets that have recently become available. We incorporated bias corrections into the length-weight and weight-length equations and used robust regressions for the length conversions. Equations for each species are given by sex and also for combined sexes, so that conversions can be made whether the sex of the specimen is known or not.