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Home , Bluntnose sixgill shark, Prickly shark, Sandbar shark, Smooth hammerhead

Pacific Science (1996), vol. 50, no. 4: 382-392 © 1996 by University of Hawai'i Press. All rights reserved

Shark Records from Longline.Fishing Programs in Hawai'i with Comments on Pacific Ocean Distributions 1

GERALD L. CROW,2 CHRISTOPHER G. LOWE,3 AND BRADLEY M. WETHERBEE3

ABSTRACT: This paper summarizes records from programs conducted in Hawai'i between 1959 and 1980. Data from 11 of (173 individual sharks) are reported and compared with worldwide records. Although much of the data is nearly 30 yr old, the information was never fully utilized and represents the following important findings. The relationship be­ tween clasper length and total length (TL) for bluntnose sixgill , Hex­ anchus griseus (Bonnaterre), indicates that males mature at about 309 cm TL. High fecundity (114 pups) is reported for the , cookei Pietschmann. The smallest mature male E. cookei (183 cm TL) and the smallest pregnant (205 cm TL) , altimus (Springer), are re­ corded. New maximum depth of capture records for the , Carcharhinus Umbatus (Valenciennes), at 64 m, and for the smooth hammer­ head shark, zygaena (L.), at 68 m, are also documented. Distributions of deep-sea sharks in Hawai'i appear to be associated with isothermic sub­ mergence, and the sharks remain below the thermocline (100-400 m) and in water temperatures of 9-12°C. Carcharhiniform sharks in Hawai'i range to greater depths than reported elsewhere; this appears to be correlated with the Tropics having warmer water temperatures (20-26°C), which extend down to 100-400 m in depth.

HISTORICALLY, SHARK ATTACKS in Hawai'i Hawai'i were conducted between 1959 and have resulted in the establishment of shark 1976 (for additional details see Wetherbee et control programs (Wetherbee et al. 1994). al. [1994]). In addition to the control pro­ Recent attacks in Hawai'i have placed re­ grams, sharks were caught by longline during newed emphasis on understanding the biol­ the Resource Investigations in the North­ ogy of sharks. Shark control longline fishing western Hawaiian Islands (RINWHI) con­ programs have targeted potentially danger­ ducted from 1978 to 1980 (De Crosta et al. ous shark species, but have also resulted in 1984). These longline fishing programs cap­ the capture of a number of poorly under­ tured IS species of sharks. Despite this ex­ stood species. Six shark control programs in tensive fishing effort, accounts have been published for only four of the IS species of sharks, including the sandbar, Carcharhinus 'Original funding for the shark control programs was plumbeus (Nardo) (Wass 1973); gray reef, provided by NSF GB-6139, Oceanic Institute, and the C. amblyrhynchos (Bleeker) (Wass 1971, State of Hawai'i. The work in the Northwestern Hawai­ De Crosta et al. 1984, Radtke and Cailliet ian Islands was supported in part by the University of 1984); Galapagos, C. galapagensis (Snod­ Hawai'i Sea Grant Program under grants from NOAA Office of Sea Grant, Department of Commerce, by Proj­ grass & Heller) (De Crosta et al. 1984, We­ ect NI/R-4 and Institutional Grants NA79AA-D-00085 therbee et al. 1996); and the tiger, Galeocerdo and NA8IAA-D-00070. Manuscript accepted 26 Jan­ cuvier (Peron & LeSueur) (De Crosta et al. uary 1996. 1984, Lowe et al. 1996). 2Waikiki Aquarium, University of Hawai'i at Manoa, Honolulu, Hawai'i 96815. The purpose of this paper is to summarize 3Department of Zoology, University of Hawai'i at records of II species of sharks captured by Manoa, Honolulu, Hawai'i 96822. longline fishing in Hawai'i, with an emphasis 382 Shark Fishing Records from Hawai'i-CRow ET AL. 383 on biological data of poorly investigated (USNM), Washington, D.C., and the Bernice species. In addition, this paper updates the P. Bishop Museum (BPBM), Honolulu, Ha­ geographic distribution of these species in the wai'i. The collection catalog numbers are Pacific Ocean. provided for the uncommon species. Sharks captured during fishing programs were brought on board the boat and mea­ sured for total length (TL) and precaudal MATERIALS AND METHODS length (PCL) in cm. For male sharks, clasper For a review offishing methods, locations, length and width were recorded. In addition, and catch per unit effort around the main claspers were examined to determine the Hawaiian Islands, see Wetherbee et al. (1994) degree of calcification. For female sharks, and in the Northwestern Hawaiian Islands maximum ova diameter and the width of the see De Crosta et al. (1984). Surface water uterus were measured; the presence or ab­ temperatures around O'ahu during the 1967­ sence of pups, sex of embryos, and TL of 1969 program ranged from a winter low of pups were also recorded. Recognizable prey 23°C to a summer high of 28°C (Wass 1971). items from stomach contents were identified All shark program data were combined and to the lowest possible taxon. reported in individual species accounts except for four species, where sample size was lim­ ited. The individual species accounts were RESULTS AND DISCUSSION divided into the following sections: (1) mu­ seum collections; (2) distribution of speci­ Eleven shark species (173 sharks) in this mens from Hawai'i, with a comparison with report were captured during longline fishing Pacific Ocean and worldwide geographic and programs (Table 1). Because the University depth records; (3) reproduction; and (4) diet. of Hawai'i program in 1967-1969 composed The common and scientific names follow the major data set, these data were used to Compagno (1984). During the 1959-1960 evaluate depth distributions and provide and 1967-1969 shark control programs, se­ catch per unit effort (standardized per 100 lected voucher specimens were sent to the hooks) at different depth intervals (converted U.S. National Museum of Natural History from 20-fathom intervals) (Table 2).

TABLE I

NUMBERS OF SHARKS IDENTIFIED TO SPECIES (EXCLUDING Pups) REPORTED IN THIS PAPER CAUGHT DURING SHARK FISHING PROGRAMS IN HAWAI'( BETWEEN 1959 AND 1980 (DATA FROM DE CROSTA ET AL. 1984 AND WETHERBEE ET AL. 1994)

SPECIES'

PROGRAM" H. g. E. c. C. c. 1. o. P.m. e. al. e.r. C.1. P. g. S. I. S. z.

BW (1959-1960) II 3 2 12 4 OI (1966-1968) 2 UH (1967-1969) 9 10 2 2 9 44 23 10 SH (1971) I 19 N (1976) I 1 RINWHI (1978-1980) 4 I Total 20 13 4 5 2 9 68 36 14

• BW, Billy Weaver program; 01, Oceanic Institute program; UH, University of Hawai'i program; SH, State of Hawai'i program; N, Naftel et al. unpubl.; RINWHI, De Crosta et al. (1984). b H. g., griseus; E. c., Echinorhinus cookei; C. c., Carcharodon ; I. 0., oxyrinchus; P. m., Pseudo/riakis microdon; C. aI., Carcharhinus altimus; C. f., Carcharhinus falciformis; C. I., Carcharhinus Iimba/us; P. g., Prionace glauca; S. I., Sphyrna lewini; S. z., Sphyrna zygaena. 384 PACIFIC SCIENCE, Volume 50, October 1996

TABLE 2

NUMBERS OF SHARKS CAPTURED AT DEPTH INTERVALS DURING THE 1967-1969 SHARK CONTROL PROGRAM OF THE UNIVERSITY OF HAWAI'I

SPECIES· HOOK HOOKS SHARKS/l 00 DEPTHS (m) RECOVERED H. g. E. c. I. o. P.m. C. al. C. f. c.1. S. 1. S. Z. HOOKS (CPUE)

0-37 4,114 I 24 15 3 1.1 38-73 5,295 2 20 7 6 0.7 74-110 481 0.2 111-146 137 I 1.5 147-183 103 I 1.9 184-220 171 2 1.2 221-256 15 0.0 257-293 63 0.0 294-329 32 3 9.4 330-366 105 8 3 2 13.3 367-402 66 2 4.5

NOTE: Depth intervals were standardized to catch per unit effort (CPUE) for 100 hooks. •Abbreviations of shark scientific names as in Table I.

Four species of sharks were caught in captured II November 1959, 243.8 cm TL, very low numbers. Four great white sharks, 159 kg; USNM 220178, captured 9 March Carcharodon carcharias (L.), were caught in 1968, 308 cm TL, male in pieces; USNM the control programs; three were captured 206071, captured 9 March 1968, no fur­ between December and March, at depths of ther information; USNM 232588, captured 9 33 to 47.5 m. Two were captured on the west March 1968, skull only. coast of the island of Hawai'i (no size re­ DISTRmUTION. Twenty bluntnose sixgill ported), one on the north shore of the island sharks were caught during the control pro­ of O'ahu (348 cm TL), and one on the east grams on deep longline sets off the southern coast of O'ahu (279 cm TL). Taylor (1985) and western coasts of O'ahu. Specimens were provided additional records of great white captured on bottom longline sets between sharks in Hawai'i. Five shortfin mako sharks, 110 and 366 m, and all but one were caught [surus oxyrinchus Rafinesque, were captured deeper than 330 m (Table 2). An additional in control programs off the north and south male specimen was captured off the south shores of O'ahu and the west coast of the coast of O'ahu at a depth of 347 m on 21 island of Maui at depths that ranged from March 1995. This species has also been ob­ 34.7 to 54.9 m. Males measured 152 to 237 served by submersible on the east coasts of cm TL (n 3) and females were 338 and = the islands of Hawai'i and O'ahu at depths 355.6 cm TL. A 229-cm TL female silky between 500 and 1400 m (Chave and Mundy shark, Carcharhinus falciformis (Bibron), was 1994). In the Hawaiian Island chain, blunt­ captured off the east coast of O'ahu in 37 m. nose sixgill sharks range from the island A , Prionace glauca (L.), 228.6 cm of Hawai'i, throughout the Northwestern TL, was hooked off the south coast of O'ahu Hawaiian Islands, to Kimmei Seamount at an estimated depth of 47.5 to 51.2 m. (34°54'-35°36' N, 170°43'-172°00' E) of the southern Emperor Seamounts (Humphreys Species Accounts et al. 1984, Borets 1986, Chave and Mundy 1994). , Hexanchus griseus Worldwide, this species has been reported (Bonnaterre) from the surface to at least 1875 m (Com­ MUSEUM COLLECTIONS. BPBM 9649, captured pagno 1984). Yano and Kugai (1993) re­ 9 March 1968, 276 cm TL; USNM 179770, ported the capture of seven bluntnose sixgill Shark Fishing Records from Hawai'i-CRow ET AL. 385

TABLE 3

RELATIONSHIP OF CLASPER LENGTH TO BODY LENGTH OF THE BLUNTNOSE SIXGILL SHARK, Hexanchus griseus, FROM O'AHU, HAWAI'I

DATE OF CAPTURE TL (cm) PCL (cm) CLASPER LENGTH (cm) CALCIFIED

21 March 1995 273 196 14.0 No 9 March 1968 276 199 17.0 No 9 March 1968 308 224 18.5 No 9 March 1968 309 225 26.2 Yes 9 March 1968 326 238 21.4 Yes 24 March 1968 326 239 23.0 Yes 28 May 1968 331 241 24.0 Yes

sharks on bottom longlines in Okinawa at a had calcified claspers (Branstetter and Mc­ narrow depth range of 400 to 550 m while Eachran 1986). fishing at depths that ranged from 210 to A 378-cm TL female, with small ova, 1 1250 m. In Bermuda, two bluntnose sixgill rom maximum diameter, was captured in sharks tracked using acoustic transmitters March, in Hawai'i. No pregnant females showed an orientation to the Bermuda es­ were captured in this study. Female sharks carpment, typically remaining within a 600­ have been reported to mature at about 421­ to 1100-m depth range in 9SC water (Carey 482 em TL (Compagno 1984, Ebert 1986). and Clark 1995). Hubbs (1952) suggested This species has been reported to exhibit isothermic submergence to explain the pres­ aplacental viviparity, with litters that ranged ence of the bluntnose sixgill shark in the from 22 to 108 and a 65- to 70-cm TL size Tropics. at birth (Compagno 1984). Ebert (1986) re­ In the Pacific, this species has been re­ ported that a 421-cm TL shark was pregnant ported from Hawai'i, Okinawa, , Tai­ with 51 pups that measured 68-73.6 em TL. wan, Malaysia, Sumatra, , New DIET. Of nine stomachs examined from Zealand, , Guam, Enewetak, Aleutian Hawaiian sharks, two contained unidentified Islands to Baja , Mexico, and remains and another had a cepha­ (Kami 1971, Compagno 1984, Randall 1986, lopod beak. In South , ontogenetic Yano and Kugai 1993). In addition, this dietary shifts have been reported for the species has been reported to be almost cos­ bluntnose sixgill shark (Ebert 1994). The diet mopolitan, inhabiting tropical to temperate of juvenile bluntnose sixgill sharks <120 em waters of all oceans and the Mediterranean TL consisted of 54% , 5% sharks, Sea (Compagno 1984, Borets 1986). and 40% , whereas the diet of sharks REPRODUCTION. In this study, eight males >200 em TL included 11 % cephalopods, 11% measured 273 to 331 em TL, and two fe­ chimaerids, 29% te1eosts, 18% , and males were 311 em and 378 em TL. For 11 18% cetaceans (numbers expressed as percen­ additional specimens, no size was reported. tage frequency of occurrence) (Ebert 1994). Males 273-308 em TL had uncalcified clas­ pers, whereas males 309-331 em TL had cal­ Prickly shark, Echinorhinus cookei Pietsch­ cified claspers and appeared to be mature. mann Information on size at maturity for male bluntnose sixgill sharks from Hawai'i repre­ MUSEUM COLLECTIONS. USNM 179768, cap­ sents the largest data set reported for this spe­ tured 6 November 1959, pregnant female cies and is summarized in Table 3. Clark and 304.8 em TL, mold made of specimen 267 Kristof (1990) reported the capture of a ma­ kg; USNM 179805, 90 pups from the above ture 287-cm TL male from Bermuda. A 325­ specimen in two jars; USNM 179769, captured em TL male caught in the 9 November 1959, 238.8 em TL, 136 kg. 386 PACIFIC SCIENCE, Volume 50, October 1996

DISTRIBUTION. Thirteen prickly sharks were from Japan, California, , and captured during Hawaiian control programs (Taniuchi and Yanagisawa 1983). on deep longline sets off the southern coast REPRODUCTION. Seven males ranging be­ of O'ahu. Depth of capture ranged from 177 tween 183 and 233 cm TL and two females to 370 m, and all but one were caught deeper 184 cm and 304.8 cm TL were captured in than 294 m (Table 2). The prickly shark Hawai'i. No size was reported for four addi­ was originally described from Hawai'i off tional specimens. All male sharks caught in the south coast of the island of Kaua'i Hawai'i had calcified claspers and appeared (Pietschmann 1930). Submersible observa­ to be mature. Apparently this species ma­ tions have been made from the southern tures at a smaller size than the 220 cm TL coast of the island of Hawai'i and Cross reported by Compagno (1984). A 184-cm Seamount (18°44'N, 158°15'W) over sandy TL female captured in August had a maxi­ bottoms at depths of 360-420 m (Chave mum ova diameter of 6 mm, and a 304.8-cm and Mundy 1994). The prickly shark occurs TL female captured in November was preg­ throughout the Hawaiian Island chain to nant with 114 pups, which were reported to Kimmei Seamount (Borets 1986, Chave average 61 cm TL (Ikehara 1961). However, and Mundy 1994). recent measurements of pups showed an Depths of capture records worldwide average of 21.6 cm TL (range 16.5-24.1 cm, range from 11 to 650 m (Compagno 1984, n 20) in the USNM collection (Jerry Finan, Kobayashi 1986). Prickly sharks have been = pers. comm.). Females are reported to be captured at depths between 550 and 650 m adult at 299 cm TL (Compagno 1984). Size off Japan (Kobayashi 1986). This shark was at birth has been reported to be about 45 cm observed on the Nazca Submarine Ridge (off TL (Compagno 1984). the coast of Chile), swimming 0.3 to 1.3 m over the top of seamounts at 300 to 340 m DIET. Of nine stomachs examined from (Golovan and Pakhorukov 1987). Prickly Hawaiian prickly sharks, four had unidenti­ sharks have also been observed by scuba fied teleost remains and one contained shark divers in the Monterey Submarine Can­ remains. This species has been reported to yon, Monterey, California, at depths of 15­ feed on a wide variety of organisms including 35 m, either singly or in groups of up to 30 , , shark, blunt­ sharks (Crane and Heine 1992). This species nose sixgill shark, , hake, , was captured in 5.5-6.0°C water on bottom rockfish, , topsmelt, and gill net sets off Japan (Kobayashi 1986), (Compagno 1984). and Chavez-Ramos and Castro-Aguirre (1975) suggested a preferred temperature False cat shark, Pseudotriakis microdon range of 9-11 °C, which may dictate geogra­ Capello phic depth distribution. Hubbs (1952) sug­ MUSEUM COLLECTIONS. BPBM 9653, cap­ gested isothermic submergence to explain tured 24 March 1968, 274 cm TL; BPBM the presence of the prickly shark in the 9654, captured 4 September 1968, 264 cm Tropics. TL, head only. Prickly sharks have been reported only from the Pacific Ocean at the following loca­ DISTRIBUTION. Two false cat sharks were tions: Hawai'i, Japan, Taiwan, Palau, central caught in the Hawai'i control programs dur­ California to the , Isla ing deep longline sets: one each off the south­ Guadalupe, Mexico, Peru, Chile, and New ern and western coasts of O'ahu. Specimens Zealand (Kato et al. 1967, Chavez-Ramos were captured at depths of 366 and 371 m and Castro-Aguirre 1975, Flores and Rojas (Table 2). A false cat shark was observed 1979, Taniuchi and Yanagisawa 1983, Com­ during a submersible dive off southern O'ahu pagno 1984). Prickly sharks were mis­ at 500 m (Chave and Mundy 1994). identified as the , Echinorhinus Yano and Kugai (1993) reported the cap­ brucus (Bonnaterre), in capture records ture of 22 false cat sharks from Okinawa on Shark Fishing Records from Hawai'i-CRow ET AL. 387 deep bottom longlines at depths that ranged able depth range of 25-810 m (Compagno from 470 to 899 m while fishing between 210 1984, Stevens and McLoughlin 1991). and 1250 m. False cat sharks were also cap­ In the Pacific, the bignose shark has been tured on bottom gill nets in Japan at depths reported from Hawai'i, Taiwan, China, Gulf of 300-500 m (Kobayashi 1986). Worldwide, of California, southern Mexico, Columbia, this species has been reported to be asso­ , Revillagigedo Islands, and Aus­ ciated with the bottom and has never been tralia (Compagno 1984, Chen et al. 1985, caught shallower than 200 m, with a max­ Stevens and McLoughlin 1991). This species imum depth of capture at 1500 m (Com­ has also been reported from the Indian and pagno 1984). Atlantic oceans and the Mediterranean and This species has been reported in the Pa­ Red seas (Compagno 1984). cific from Hawai'i, Okinawa, Japan, Taiwan, REPRODUCTION. Four males caught in Ha­ and (Compagno 1984, Yano wai'i ranged from 115 to 152 cm TL, and 1992, Yano and Kugai 1993). The false cat five females ranged from 147 to 244 cm TL, shark has also been reported from the Indian with no size reported for two additional and Atlantic oceans (Compagno 1984). females. All males were immature, with clas­ REPRODUCTION. Both sharks captured in per lengths of 3.5-5.4 cm. Male bignose Hawaiian waters were females, 264 and 274 sharks, worldwide, have been reported to cm in TL. The 264-cm TL shark was cap­ mature at between 204 and 267 cm TL tured in August and had a maximum ova (Compagno 1984, Stevens and McLoughlin diameter of 14 mm. A 275-cm TL female 1991). captured in October off New Zealand had A 147-cm TL female caught in Hawai'i, mature, ovulated eggs 30-50 mm in diame­ with a 0.5-cm uterus width and 8 mm max­ ter (Yano 1992). Compagno (1984) esti­ imum ova diameter, appeared to be im­ mated size at maturity for males to range mature. Two Hawaiian bignose sharks were from 200 to 269 cm TL, and for females pregnant. A 244-cm TL shark captured in from 212 to 295 cm TL. Yano (1992) re­ August had 11 embryos that averaged 5.8 cm ported embryonic nutrition to be matrotro­ TL, and a 205-cm TL female captured in phic oophagy, with one embryo per uterus November had three embryos that averaged and a near-term size of 116-120 cm TL. 29 cm TL. The 205-cm TL female was the smallest pregnant bignose shark recorded, DIET. Of the two false cat sharks captured indicating that female bignose sharks mature in Hawai'i, one contained unidentified teleost at a smaller size than the 226-282 cm TL re­ remains. Yano and Musick (1992) reported ported by Compagno (1984). This species is cephalopods, shark remains (including Squal­ viviparous, with a -sac , and re­ idae), and teleosts from sharks captured in ported litter sizes of 3-15, and a birth size of the Pacific. Stomach contents from specimens 70-80 cm TL (Compagno 1984). A 60-cm captured off Japan consisted of octopus and TL free-swimming bignose shark with a Heterocarpus (Kobayashi 1986). fresh umbilical scar was caught off Australia (Stevens and McLoughlin 1991). Bignose shark, Carcharhinusaltimus(Springer) DIET. Of the seven sharks examined in MUSEUM COLLECTIONS. BPBM 9651, cap­ Hawai'i, two stomachs contained elasmo­ tured 14 November 1967, 147 cm TL. branchs (including one whole 75-cm TL DISTRIBUTION. Nine bignose sharks were Squalus mitsukurii Jordan & Synder), and captured off the southern and eastern coasts two had teleost remains (including Scorpaen­ of O'ahu, and the southwestern coast of idae). Worldwide, this species has been re­ Kaua'i. Sharks were captured at depths that ported to feed on , cephalopods, ranged from 27 to 360 m (Table 2). World­ elasmobranchs, and a wide variety of teleosts wide, they are reported from warm-temper­ (Compagno 1984, Stevens and McLoughlin ate and tropical waters, with a highly vari- 1991). 388 PACIFIC SCIENCE, Volume 50, October 1996

Blacktip shark, Carcharhinus limbatus (Va­ reported mature females as small as 120 cm lenciennes) TL. In , maximum ova diameter measured during the mating season was 34 DISTRIBUTION. Sixty-eight blacktip sharks mm (Dudley and Cliff 1993). This species were caught during fishing programs (64 was reported to exhibit viviparity with a from the main Hawaiian Islands and four yolk-sac placenta, a 12-month gestation with from the Northwestern Hawaiian Islands), litters ranging from 1 to 11, and a size at between 13 and 64 m (Table 2). The capture birth of 38-72 cm TL (Compagno 1984, at 64 m represents a new depth record for this Dudley and Cliff 1993). species. Previously, this species was docu­ mented from shallow coastal waters rarely DIET. Of the 20 blacktip sharks examined deeper than 30 m (Compagno 1984). in Hawai'i, seven had food in their stom­ In the Pacific, this species has been re­ achs. Six contained teleost remains (including corded from Hawai'i, Australia, New Guinea, Anguilliformes, Muraenidae, and Sphraeni­ Java, Borneo, , Tahiti, Mar­ dae), one an ophiuroid, and one a cephalo­ quesas, , Thailand, China, Tai­ pod. The diet of 655 South African blacktip wan, southern California to Peru, and the sharks, expressed as percentage frequency of Revillagigedo and Gahipagos Islands (Com­ occurrence, consisted of 83% teleosts, 16% pagno 1984). Worldwide, they are reported elasmobranchs, 10% cephalopods, 4% crusta­ to be common in tropical and warm-temper­ ceans, and <1% cetaceans (Dudley and Cliff ate inshore and offshore waters of the Atlan­ 1993). tic and Indian oceans and the Mediterranean and Red seas (Compagno 1984). Scalloped , Sphyrna lewini REPRODUCfION. Ninteen male blacktip (Griffith & Smith) sharks captured in Hawai'i measured 108­ 201 cm TL, and 15 females were 116-215 DISTRIBUTION. Thirty-five scalloped ham­ cm TL. No data were reported for 14 addi­ merhead sharks were caught in the main Ha­ tional sharks. Male blacktip sharks 108-163 waiian Islands and one from the Northwest­ cm TL had uncalcified claspers, whereas ern Hawaiian Islands. These sharks were males 182-201 cm TL had calcified claspers captured at depths that ranged from 6 to and appeared to be mature. Size at maturity 139 m (Table 2). The maximum depth ofcap­ of the b1acktip shark is variable depending on ture record for Hawai'i was from a gill net at geographic location. Killam and Parsons 275 m (Clarke 1971). In Hawai'i, Clarke (1989) reported male maturity at 133-136 (1971) studied the ecology of juveniles, and cm TL for sharks from Tampa Bay, . Holland et al. (1993) studied activity pat­ In , the smallest mature male was 155 terns of juveniles in Kane'ohe Bay, O'ahu. cm TL (Devadoss 1988), and Dudley and Adult sharks in Ha­ Cliff (1993) reported 50% of the males were wai'i appear to be offshore in deeper water mature at 199-204 cm TL in South Africa. and enter coastal waters for mating and pup­ In Hawai'i, female blacktip sharks began ping (Clarke 1971). Worldwide, this species to mature at about 176 cm TL and the has been recorded as circumglobal, from smallest pregnant shark was 184 cm TL. Lit­ coastal and pelagic, semioceanic, warm-tem­ ters ranged from two to seven pups (n = 5), perate, tropical waters from the surface to and ovulation occurred in June and July with 275 m (Compagno 1984). maximum ova diameters of 40-47 mm. In the Pacific this species has been re­ Killam and Parsons (1989) reported fe­ ported from Hawai'i, Guam, Indonesia, male maturity at 158-162 cm TL in Tampa China, Taiwan, Japan, Philippines, Aus­ Bay, Florida, and the smallest mature female tralia, New Caledonia, Tahiti, southern from India was 165 cm TL (Devadoss 1988). California to the Gulf of California, Pa­ Dudley and Cliff (1993) reported 50% of the nama, Ecuador, and Peru (Kami 1971, females were mature at 206-211 cm TL from Compagno 1984). The scalloped hammer­ South Africa, although Compagno (1984) head shark has also been reported from the Shark Fishing Records from Hawai'i-CRow ET AL. 389

Atlantic and Indian oceans and the Medi­ of ~i'ihau, and Penguin Banks. In Hawai'i, terranean and Red seas (Compagno 1984). specImens were captured at depths that ranged from 33 to 68 m (Table 2). All cap­ REPRODUCTION. Eleven male sharks cap­ tures from Hawai'i represent new maximum tured in Hawai'i measured 54-260 cm TL depth records for this species, because it pre­ and eight females were 52-309 cm TL. Mal~ viously was recorded from the surface to 20 scalloped hammerhead sharks 54-138 cm TL m (Compagno 1984). Juveniles have been re­ had uncalcified claspers, whereas males 213­ ported from coastal waters, whereas adults 260 cm TL had calcified claspers and ap­ are believed to occur offshore over deep peared to be mature. Compagno (1984) and water (Smale 1991), which may explain the Devadoss (1988) reported that males mature abs~nce of adults from the coastal longline at 140-165 cm TL. Stevens (1984) reported fishIng programs in Hawai'i. that males mature at 235-281 cm TL in Aus­ This species has been reported in the t~alia, and Chen et al. (1988) reported matu­ Pacific from Hawai'i, Thailand, Indonesia, nty between 198 and 210 cm TL in Taiwan. ~hina, Taiwa.n, Vietnam, Japan, Philip­ In Hawai'i, an immature female 214 cm pInes, AustralIa, New Caledonia, Norfolk TL had a uterus diameter of 1.5 mm. A 309­ Island, Kermadec Islands, New Zealand cm T!-- scalloped hammerhead shark cap­ Tahiti, southern California, Gulf of Califor~ tured In May was pregnant with 31 pups that nia to , Ecuador to Chile and the averaged 44.7 cm TL. Worldwide, size of Gahipagos Islands (Compagno 1984, Francis maturity for females ranged from 180 to 230 1993). This species was also captured from cm TL (Compagno 1984, Chen et al. 1988, coastal and pelagic, semioceanic, warm-tem­ Devadoss 1988). This species has been re­ perate and tropical Atlantic and Indian po~ted to be viviparous, with a compartmen­ oceans and the Mediterranean and Red seas talIzed uterus and a yolk-sac placenta with (Compagno 1984). litters that ranged from 12 to 38 (Chen et al. 1988). Worldwide, the size at birth ranged REPRODUCTION. Five males collected in from 42 to 55 cm TL (Compagno 1984). Hawai'i measured 162-202 cm TL, and three females were 197-213 cm TL. All DIET. Of 17 stomachs examined in Ha­ males were immature, with uncalcified clas­ wai'i, seven contained teleosts (including pers that ranged in length from 5.5 to 7.5 Aulostomidae), two had beaks, cm. All females examined were also imma­ two had crustaceans, one had indigestible ture. Stevens (1984) suggested that males ma­ material (mud). The percentage frequency of ture at about 250-260 cm TL and females at o~currence of prey in the diet of 108 juve­ about 265 cm TL. This species has been re­ mles from Kane'ohe Bay, O'ahu, consisted ported to exhibit viviparity, with a yolk-sac of 68% teleosts and 54% crustacea (Clarke placenta and litters that ranged from 20 to 1971). In the Gulf of California, stomach 49, and a size at birth of 50-61 cm TL contents as an index of relative importance (Compagno 1984, Stevens 1984). from 108 adult sharks included 65% teleosts 30% pelagic cephalopods, and 5% crusta~ DIET. Of the eight smooth hammerhead ceans (Galvan-Magana et al. 1989). World­ shark stomachs examined from Hawai'i, six wide, this species has also been reported had teleo~t remains (including Carangidae), to feed on gastropods and elasmobranchs five contaIned cephalopods, and one had iso­ (Compagno 1984). pods. In South Africa, stomachs of sharks <200 cm TL as percentage frequency of oc­ curren~e contained 62% cephalopods, 1% Smooth hammerhead shark, Sphyrna zygae­ chondncthyes, and 38% teleosts (Smale na (L.) 1991). The diet of 42 sharks from Australia DISTRIBUTION. Fourteen smooth hammer­ as percentage frequency of occurrence con~ head sharks were caught during the Hawai'i sisted of 76% cephalopods and 55% t~leosts control programs on shallow longline sets, (Stevens 1984). In the Gulf of California along the shorelines of O'ahu, both coasts stomach contents expressed as an index of 390 PACIFIC SCIENCE, Volume 50, October 1996

relative importance of 27 adult smooth ham­ m. Conversely, depth distribution of car­ merhead sharks included 58% teleosts and charhiniform sharks appears to be associated 43% pelagic cephalopods (Galvan-Magana with water temperatures of 20-26°C, which et al. 1989). extend down to the thermocline. The depth of the thermocline around Hawai'i may ex­ Distributions ofHawaiian Sharks plain the resulting maximum depth of cap­ ture records for the at 286 The geographic isolation of the Hawaiian m (Wetherbee et al. 1996), the at Islands provides an ideal location for the ex­ 371 m (Wetherbee et al. 1994), the scalloped amination of patterns of shark distribution. hammerhead at 275 m (Clarke 1971), and Many factors may influence shark distribu­ from this report the blacktip, at 64 m, and tion in Hawaiian waters, including food the smooth hammerhead, at 68 m. availability, space, associated biota, slope, currents, substrate , salinity, pressure, temperature, oxygen, and light (Carney et al. ACKNOWLEDGMENTS 1983). An understanding of the distribution on the Pacific Plate of most carcharhiniform This paper is dedicated to the memory of sharks has been hampered by limited access Albert L. Tester, whose scientific efforts to specimens and misidentifications. made this research possible. We thank J. Oceanic sharks (mako, silky, and blue) Stimson, J. Parrish, and the Zoology De­ have wide-ranging distributions in temperate partment, University of Hawai'i at Manoa, and tropical waters and could easily reach for maintaining the longline fishing records. Hawaiian waters by following ocean cur­ We also thank all the individuals involved in rents. The primarily coastal blacktip, scal­ the longline fishing programs for their data loped hammerhead, and smooth hammer­ collection. Special thanks to A. Suzumoto at head sharks, which are commonly associated the B. P. Bishop Museum and J. Finan at the with land masses and are semioceanic, may U.S. National Museum of Natural History have reached Hawai'i by island hopping. for checking records and providing catalog Deep-sea sharks (bluntnose sixgill, prickly, numbers. We appreciate the mauncript re­ and false cat) have been observed by sub­ view by B. Carlson, A. Suzumoto, and K. mersible, swimming directly over seamounts Yates. We thank J. Randall, K. Yano, and L. (Chave and Mundy 1994) and appear to be Yasukochi for providing selected references. associated with canyons and outcroppings. These geographic features may serve as ref­ erence points or refuging areas. Smith and LITERATURE CITED Jordan (1988) reported a current total of 30,000 Pacific Ocean seamounts that are BORETS, L. A. 1986. Ichthyofauna of the more than 1000 m in height; these areas may Northwestern and Hawaiian submarine serve as reference points. It is also possible ranges. J. Ichthyol. 26: 1-13. that submarine ridges serve as stepping­ BRANSTETTER, S., and J. D. McEACHRAN. stones by means of which deep-sea sharks 1986. A first record of noron­ reach Hawai'i. hai (Lamniformes: Odontaspidae) for the Water temperature appears to be a key western north Atlantic, with notes on factor in determining depth distribution. In two uncommon sharks from the Gulf of Hawai'i, water temperature drops abruptly Mexico. Northeast Gulf Sci. 8: 153-160. from 20-26°C to 9-12°C at the thermocline CAREY, F. G., and E. CLARK. 1995. Depth (100-400 m) (Chave and Mundy 1994). telemetry from the six gill shark, Hexan­ Deep-sea sharks from this study have been chus griseus, at Bermuda. Environ. BioI. caught below the thermocline, with the shal­ 42: 7-14. lowest depth of capture at 110m. All but CARNEY, R. S., R. L. HAEDRICH, and G. T. three were captured in water deeper than 322 ROWE. 1983. Zonation of fauna in the Shark Fishing Records from Hawai'i-CRow ET AL. 391

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