Mar. Res. Indonesia Vol.32, No.1, 2007: 7-19

SIZE, SEX AND LENGTH AT MATURITY OF FOUR COMMON CAUGHT FROM WESTERN INDONESIA

Fahmi and Kurnaen Sumadhiharga Research Center for Oceanography — Indonesian Institute of Sciences Jl. Pasir Putih I, Jakarta Utara 14430, Indonesia e-mail: fahmi_lipi@ yahoo.com

ABSTRACT A study on four common in Indonesia, the spinner shark brevipinna (Muller and Henle, 1839), Carcharhinus falciformis (Bibron, 1839), spot-tail shark Carcharhinus sorrah (Valenciennes, 1839) and scalloped hammerhead Sphyrna lewini (Griffith and Smith, 1834) was conducted at several shark landing sites in western Indonesia from March 2002 to December 2004. Data were collected from the surveyed areas including the length of frequency, sex composition and length at maturity. In general, they were caught at size smaller than their maturity size. The proportion of immature C. brevipinna, C. falciformis, C. sorrah and S. lewini to their total number recorded at the surveyed area during the study were about 87%, 50%, 80% and 65%, respectively. According to the length at maturity, females generally attained their maturity in larger size than males. Some factors contributing the catches in immature size and of those four species were also discussed. Keywords: Shark, Size composition, Western Indonesia

INTRODUCTION and their biology in Indonesia are very few. Attention on shark in Indonesia starts in 2001 Shark fishes are one of the most important through a cooperative study between Indonesia commodities in Indonesia. They are caught and on elasmobranch fishes. Several either as a target of fishing in artisanal or preliminary surveys have been conducted since as by catch in the pelagic tuna fisheries. Even then and some information about shark at several though they only contribute about 2% of the total locations in Indonesia has been recorded. production of marine fisheries in Indonesia in 2001, Four shark species are indicated as common the total catch of shark in Indonesia is 65,860 t species in Indonesian waters, namely spinner (DKP, 2003). This record makes Indonesia being shark, Carcharhinus brevipinna (Muller and recognized as a country that has the highest annual Henle, 1839), silky shark, C. falciformis (Bibron, total production of sharks in the world (Stevens et 1839), spot-tail shark, C. sorrah (Valenciennes, al., 2000; Bonfil, 2002; TRAFFIC, 2002), which 1839) and scalloped hammerhead, Sphyrna lewini is of concern due to global alarm toward the status (Griffith and Smith, 1834). They have been of shark resources. Due to their biology, sharks recorded during studies in a number offish landings and rays are more vulnerable to over-exploitation in western Indonesia, including Sumatra, Jawa, Bali than other fishes (Camhi et al., 1998; Stevens et and Nusa Tenggara. Several studies on shark al., 2000). Therefore, elasmobranch fishes are diversity in other areas also indicate that these considered as fully exploited in Indonesian waters species are quite common in the world (Amorim with indications of depletion in some areas (Bonfil, et al., 1998;Krogh, 1994; Pepperell, 1992). 2002; White et al., 2006). They are normally caught by gill nets and long In order to encourage regional concerns on lines from coastal areas to the open seas as by shark conservation and management, information catch or even as target of fishing in Indonesia. about sharks should be accumulated in each Habitat of each shark species varies, country. Unfortunately, studies on shark diversity depending on their characterizations. C.

DOI: 10.14203/mri.v32i1.427 Mar. Res. Indonesia Vol.32, No.1, 2007: 7-19

brevipinna is known as a common coastal-pelagic on their fishing areas including the Malacca Strait shark; it lives in shallow waters at a depth less (Belawan and Tanjung Balai), West Sumatra - than 30 m, but ranging down to at least 75 m depth (Bengkulu, Padang, Sibolga), South Sumatra (Compagno, 1984). C. falciformis inhabits (Lampung), South Java (Pelabuhan Ratu and oceanic waters near and beyond the continental Cilacap), and South Bali-Lombok (Kedonganan slopes, but also inhabit in coastal waters. C. sorrah and Tanjung Luar) (Fig. 1). Survey trips in Java, is common coastal, shallow water tropical shark Bali and Lombok were funded by ACIAR project, of the continental and insular shelves, primarily while survey trips in Sumatra, one trip in Bali and around coral reefs at depth up to 73 m. Whilst S. Lombok were funded by LIPI. All sites in Sumatra lewini is a coastal pelagic, semi oceanic, warm were surveyed only once and other sites were more temperate and tropical species occurring over than one trip (Table 1). continental and insular shelves and in deep water Data was collected by recording the number adjacent to them, often approaching close inshore of shark species landed including size composition and entering enclosed bays and estuaries. It based on their total length (to the nearest millimeter ranges from the intertidal and surface down to at using tape meter-scale), the outer clasper length least 275 m depth (Compagno, 1984; 1999). (to the nearest 0.1 mm using dial caliper), sex and This paper presents data on species and size maturity stages. Species identification was carried compositions of C. brevipinna, C. falciformis, out using the keys and descriptions in Compagno C. sorrah and S. lewini in western Indonesia, and (1999). also provides some biological information, such as Size distributions of each species were tested sex ratio, length at maturity and litter size. using two-samples Kolmogorov-Smirnov Test Conservation status of these species is also (Motta et al., 2005), and sex ratio between males discussed. and females of each species was analyzed using Chi-square test to determine the significant MATERIALS AND METHODS difference from the expected ratio 1:1 (Gay, 1996). Maturity stages of males were classified based A total of 14 survey trips were undertaken on the condition of the claspers. The mature males from March 2002 to December 2004 at nine were indicated by their calcified and enlarged landing sites and fish markets in western Indonesia. claspers, while females were indicated as mature These locations were grouped into five zones based by the presence of embryos, large developing ova

Size, Sex And Length At Maturity Of Four Common Sharks … (Fahmi & Kurnaen Sumadhiharga)

and the enlarged uteri (Hazin et al., 2000; Size composition Wetherbee et al., 1997; White et al., 2002). During the study, 190 females and 170 males of C. brevipinna were examined. The size of RESULTS females ranged from 710 to 2490 mm total length (TL) and males from 670 mm to 2490 mm TL. During the present studies, there were more Females were about equal in size with males than 80 shark species have been recorded, (t=0.25; P>0.05) and the Kolmogorov-Smirnov test representing 16 families. The most common shark was failed to detect the difference of size family encountered was Carcharhinidae (27 distributions between them (P>0.05). More than species), making up 33.75% of the total species 50% of males and females were recorded at size of sharks in Indonesia. C. brevipinna, C. less than 800 mm TL (Fig. 2a). falciformis, C. sorrah and Sphyrna lewini Another carcharhinid, C. falciformis was (Sphyrnidae) are the most common sharks consisted of 342 females and 330 males during occurring in Indonesian waters. They were found the study. The size of females ranged from 650 to in significant number at most of the observed fish 2800 mm TL and males from 695 to 2450 mm TL. landing sites and fish markets. A Total of 360 C. The Kolmogorov-Smirnov test was failed to detect brevipinna, 672 C. falciformis, 293 C. sorrah the difference of size distributions between them and 265 S. lewini were recorded from nine (P>0.05). About 50% of females were recorded locations (fish markets or landing sites) in Sumatra, at size less than 1429 mm TL while the 50% of Java, Bali and Lombok, represented of five zones males were between 553 and 1401 mm TL (Fig. in western Indonesia. The size ranges of these 2b). species in each location are showed in Table 2 A total of 179 females and 114 males of C. and general information on each species are sorrah were recorded. Females size ranged from showed in Table 3.

Table 2. Size ranges (in mm TL) of the most common species in the surveyed locations (n/a = not available). Mar. Res. Indonesia Vol.32, No.1, 2007: 7-19

Size, Sex And Length At Maturity Of Four Common Sharks … (Fahmi & Kurnaen Sumadhiharga)

consisting of 164 females and 96 males. The size female (3168 mm TL) that was also recorded from of females ranged from 440 to 3168 mm TL and Cilacap in October 2004. Juveniles (at size males from 430 mm to 2355 mm TL. The between 440 and 620 mm TL) represented for Kolmogorov-Smirnov test detected significant 34.33 % of the total hammerheads that have been differences in the length frequency distributions recorded in western Indonesia during the study. between females and males (P<0.05). About 50% Immature size contributed about 65% of total of females were recorded at size between 440 species recorded during the study. and 1815 mm TL while 50% males were recorded at size less than 700 mm TL (Fig. 2d). The 400 - Sex ratio 599 size class represented the most abundance Overall ratio between males and females of size class of S. lewini in western Indonesia. C. brevipinna in western Indonesia during study At least 87% of total catch of C. brevipinna was 1:1.05. This ratio indicated that there was no in all surveyed areas during this period in Indonesian significant difference from 1:1 (2=0.22; P>0.05). waters was in immature size (< 1400 mm TL) and The comparison between males and females in 55.48 % of them were juveniles (less than 800 each region were also equal (2 = 0.01 - 1.5; mm TL and having an umbilical scar). Both small P>0.05) as shown in the South Java and South and large individuals of this species were recorded Bali-Lombok regions at several occassions (Fig. in large numbers in the South Bali-Lombok region 3). during the study. The Kedonganan fish landing The overall sex ratio of C. falciformis was site in Bali contributed 67.61 % of total immature 1:1.04. This ratio was not significantly different sharks recorded in the region (215 individuals). from ratio 1:1 (2= 0.42, P>0.05). Generally, the Conversely, most of larger sharks were recorded proportions of males and females were equal in at the Tanjung Luar landing site in Lombok. At each region (2= 0.07 - 1, P>0.05). The sex this area, 51.39 % of the spinner sharks were ratio of this species in South Java and South Bali- considered as mature (more than 1600 mm TL). Lombok regions was also equal except for June Almost 50 % of total catch of C. falciformis 2002 in South Java (2=4.; P<0.05) and for August in all surveyed areas during the study in Indonesian 2002 in South Bali-Lombok region (2= 4.84.; waters was in immature size (< 1400 mm TL), but P<0.05). Females were dominated in the less than 5% of them were juveniles (less than abundance of C. falciformis in both occassions 700 mm TL and having an umbilical scar). Female (Fig. 4). juveniles contributed 1.94% and male juveniles The overall ratio between males and females were only 0.30% of the total number of silky sharks of C. sorrah was 1:1.57 and the Chi Square test recording in western Indonesia during this study. showed a significant difference from the expected The most abundant sharks were recorded from sex ratio 1:1, which females were more abundant the South Bali-Lombok region (69.30%), especially than males (2 = 14.20, P<0.05). Based on the from the Tanjung Luar landing site. region, the sex ratios in the Malacca, West Sumatra The smallest C. sorrah (520 mm TL) was and South Java were generally equal (2 = 1 - recorded from Tanjung Balai landing site in the 2.30; P>0.05). In contrast, the sex ratio in other Malacca Strait region and the largest (1572 mm regions (South Sumatra and South Bali-Lombok) TL) was from Tanjung Luar landing site in the was different significantly (2= 4.17 and 13.12; South Bali-Lombok region. During the study, this P<0.05). The obvious difference in the proportion species was commonly caught at size between 520 between males and females in the South Bali- and 1030 mm TL. About 80% of total number of Lombok was showed on the comparison of both C. sorrah recording during the study was sexes in April 2004 with the ratio 1:14 (Fig. 5). immature (< 1100 mm TL). A large number of The overall males and females ratio of the those species recorded from Tanjung Balai landing scalloped hammerhead sharks, S. lewini, was site contributed most. 1:1.71 and it showed a significant difference from On the other hand, a male juvenile of this the expected ratio 1:1 (2= 17.78, P< 0.05). Based scalopped hammerhead from Cilacap, South Java on the region, the sex ratio in the South and West (432 mm TL) was considered as the smallest Sumatra and South Java was generally equal (2 = species recorded and the largest 5. lewini was a 0.13 - 1.67; P>0.05). In contrast, the overall Mar. Res. Indonesia Vol.32, No.1, 2007: 7-19

Size, Sex And Length At Maturity Of Four Common Sharks … (Fahmi & Kurnaen Sumadhiharga)

Mar. Res. Indonesia Vol.32, No.1, 2007: 7-19

embryos size was varied between 135 mm and mm TL and the smallest mature male spot-tail 350 mm TL, depending on the reproductive stage shark was also recorded at the same size. On the of the mothers. The mature sharks were recorded other hand, mature females were receded at size only at Tanjung Luar (South Bali-Lombok) and between 1328 and 1572 mm TL. The biggest Pelabuhan Ratu (South Java region). In Tanjung female shark was recorded at Tanjung Luar landing Luar landing site, the mature sharks (both females site. Pregnant females were recorded at size and males) represented for 22.47% of total silky between 1328 and 1348 mm TL. During this study, sharks recording in this area. Conversely, there the number of embryos was varied from five to were no mature female sharks recorded at six embryos at size between 315 and 353 mm TL. Pelabuhan Ratu landing site and mature males Mature C. sorrah were only recorded at Tanjung represented only 6.58% of the total silky sharks Luar and Sibolga (West Sumatra region), recorded during the study. In general, mature representing 56.32% of the total number of spot- males and females of silky sharks from western tail sharks recorded from those areas. Indonesia represented 10.13 and 4.02% of the total In general, males of 5. lewini attained their number of the species recorded during the study, maturity at 1620 mm to 1812 mm TL. Figure 7d respectively. shows the relationship between the length of During the study, male spot-tail sharks reached claspers and the total length of male scalloped their full maturity at size between 1030 and 1200 hammerhead. The increase of claspers length of mm TL. There was a gap in the transition between male 5. lewini when they reached maturity was the mature and immature male sharks because not as rapid as other three carcharhinids in this inadequate data of the mature males (Fig. 7c). study. The largest immature male was recorded However, there was a rapid increase in the length at size 1700 mm TL, while the smallest mature of claspers when this species reached its maturity. male was at 1620 mm TL. Conversely, mature The largest immature male was recorded at 1030 females attained their maturity from 2130 mm TL. Size, Sex And Length At Maturity Of Four Common Sharks … (Fahmi & Kurnaen Sumadhiharga)

Size, Sex and Length at Maturity of...

During the study, pregnant females were recorded Conversely, the size and sex ratio C. sorrah and at size between 2830 mm and 3060 mm TL. The S. lewini were significantly different. Females number of embryos in the uteri varied from 13 to were larger than males and the size distribution 28 embryos and the sizes were between 174 mm between both sexes was not equal. The range sizes and 415 mm TL, depending on the embryonal of females were generally wider than males for development stages. A 2830 mm female of C. sorrah and S. lewini. The maximum total scalloped hammerhead was recorded carrying length of females was also higher. This could be embryos consisting of 18 males and 10 females at meant that the growth rate of females was higher size between 320 and 370 mm TL. In addition, the than males. A study on age and growth of blue mature hammerhead sharks were commonly shark Prionace glauca in the North Atlantic caught only in the South Bali-Lombok region. They Ocean concluded that when males and females represented 19.62% of the total hammerheads that attained five years old, the growth rate of males have been recorded in Indonesia during the study. was getting slow while the growth rate of females On the other hand, the West Sumatra region only remained constant (Skomal and Natanson, 2003). contributed for 3.77 % of the total mature This condition might be happened to other shark hammerheads recording during the study. species. During the study, a female C. brevipinna attained up to 2900 mm TL. This was a new record DISCUSSION for the maximum size of this species in the world. The maximum total length of this species that has According to the size distribution and sex ratio, been recorded before was 2780 mm (Compagno, the proportion between males and females of C 1984; 1999). brevipinna and C. falciformis were about equal.

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Sex ratio between males and females showed sharks. This situation is not a good sign for the that females were caught more frequent than sustainability of shark resource, regarding to the males. There was an idea of segregation between biological characteristics of these species. Due to females and males that occurred at different area, their biology, sharks are more vulnerable to over- as suggested by Heithaus (2001). Another exploitation than other fishes. Sharks are long lived, possibility was adult females may occur at have a long gestation periods (nine to 22 months), shallower waters to give birth (Simpfendorfer, slow growth, late age at maturity (ten to twenty 1992). The difference of maximum size between years for some species), low fecundity and low males and females was also related to the natural mortality (Coleman, 1996; Camhi et al., difference in the length at maturity of each sex. 1998; Stevens et al., 2000; Bonfil, 2002; Cavanagh Males were usually faster in attaining its maturity et al., 2003). There will be a small chance for than females. According to Branstetter (1987), these species to recover from their exploitation if the size at maturity of females of C. falciformis the existence of female sharks in nature is threated. from the north-western Gulf of Mexico was more In addition, the exploitation on the immature sharks than 2250 mm, with an estimated age of seven to make they have no opportunity to get mature and nine years, while the size at maturity of males was reproduce. This will lead to the extinction for these between 2100 and 2200 mm with an estimated species in the next decades if there is no control age of 6-7 years. Conversely, Oshitani et al. and assessment for the shark fishery in Indonesia. (2003) examined the age and growth rate of C. In general, juveniles and sub adult sharks tend falciformis from the Pacific Ocean and found that to occur in the coastal area and shallow waters. males considered attaining its maturity in estimated Larger sharks mostly occur in the deeper waters age of five to six years, while females in age of or open seas while coastal and shallow waters are six to seven years and had larger size. Males known as nursery area for juveniles of some shark attained maturity at 1350 to 1400 mm (precaudal species (Castro, 1993; Carlson, 1999). This length) and females were at 1450 to 1500 mm. condition makes immature sharks can be caught The range size at maturity of male C. falciformis easier than the adults. The tendency of catching in this study was presumably shorter than the size immature sharks by Indonesian fishers was not range mentioned by Branstetter (1987), Compagno only caused by lack of their knowledge but also it (1999) and Oshitani et al. (2003). On the other depends on several factors such as fishing gear hand the size at maturity of C. sorrah in western type, size and capability of fishing boat and fishing Indonesia was about equal in size at maturity of areas. the same species from northern Australia Fishing gears became one of the main factors (Davenport & Stevens, 1988). A condition when in determining this variation. Long lines and gill sharks attained their maturity in earlier time could nets were the most common fishing gears that were be indicated as one of the species adaptation used for shark fishing. Size variation of the methods for the pressure such as over exploitation captures was dependent on the hook size of the or natural selection (Lucifora et al., 1999). long lines or mesh size of the gill net. Hence, larger In this study, the size at maturity for female S. hooks or mesh size of the net will catch larger lewini from western Indonesia was much larger sharks ideally. Long lines were quite common to than those mentioned by Compagno (1999) or be used by fishers from Tanjung Luar (South Bali- recorded from other region such as northeastern Lombok region) and South Java region, while gill Brazil. The size of mature females of scalloped nets were common to be used in the Kedonganan hammerhead sharks recorded in northeastern (South Bali-Lombok region), West Sumatra, South Brazil was from 2135 to 2550 mm TL, while the Sumatra and Malacca Strait regions. The mesh litter size ranged from two to 21 embryos (Hazin size of the gill nets was also varied in each region. et al., 2001). Due to inadequate data of mature The gill net that is specialized for shark catching is females recorded in western Indonesia during the called as 'Shark net' or tangle net, which has large study, the result for length at maturity of female S. mesh size (up to 20 inches) and it is operated by lewini was not representative. medium to large sized boat (more than 10 m in Shark fishing activities in western Indonesia length). This fishing gear has ability to catch are faced to a fact that generally the Indonesian medium to large sharks (one meter in length or fishers tend to catch a large number of immature more) and rarely catch the smaller sharks (less Size, Sex And Length At Maturity Of Four Common Sharks … (Fahmi & Kurnaen Sumadhiharga)

than one meter in total length). The type of gill endangered species in the future if the exploitation nets like this was commonly used by fishers from keep continues without any management actions. Sibolga and Bengkulu (West Sumatra). On the Therefore, further studies should be taken to other hand, other fishers from Kedonganan (South estimate the sustainable stock for those species Bali-Lombok), Labuhan Maringgai (South and to make recommendation for preparing a better Sumatra), Pelabuhan Ratu (South Java) and management and regulation of shark fishing in Tanjung Balai (the Malacca Strait) and other areas Indonesia. in Indonesia are using smaller mesh-size gill nets and long lines to catch fish as target of CONCLUSION fishing. They do not catch sharks as target species but only as by catch. Unfortunately, they often The captures of young sharks and more get small sharks in their catches and sometimes females than males by Indonesian fishers can the number of sharks that are being caught is affect the recruitment process of shark recources greater than the target fishes. Some of those and their ability to recover from the exploitation. fishers also make sharks as their main target in Lack of facilities and abilities to catch fishes in order to get their fins. Other factors related to the the further areas from the coastal zones were the immature shark catching are fishing boat and the main reason why Indonesian fishers caught the area of fishing. In general, local fishers or artisanal young more frequent than the adults. Moreover, fishers cannot afford to have big boat for their socio-economical factors and the acknowledgment effort. They only have small boats with simple of fishers about shark characteristics are also instruments. This condition makes Indonesian contributing on that condition. Therefore, fishers are fishing close to the shore and in shallow Indonesian government should have a good waters (less than 60 m depth). The daily-trip management for sustainability of shark fisheries gillnetters usually get small sharks and rarely get and find out a better solution for shark fisheries in large sharks in their fishing grounds, while their this country. boats are also not designed to load large fishes (>200kg). Acknowledgements. We thank to Dr. Stephen Blaber from Commonwealth Scientific and Shark Status Industrial Research Organization (CSIRO) Australia for giving the opportunity presenting this Even though spinner shark, silky shark, spot- th tail shark and scalloped hammerhead are quite paper in 7 Asian Fisheries Forum in Penang, common in Indonesian waters, the World Malaysia, ACIAR project team who helped Conservation Union (IUCN) classifies three of collecting the data: Dr. William White (Murdoch them as "Near threatened (NT) status" species in University Australia / CSIRO Hobart) and Drs. the IUCN red list table for C. brevipinna, C. Dharmadi (RCCF), also LIPI project team: Drs. sorrah and Sphyrna lewini (IUCN, 2005). This M. Adrim and P. Agustono. status is given to these three species because they are more conducive to become endangered in the REFERENCES future if there is no management action for them. In addition, generally all sharks are vulnerable to Ali, A., Hilmi, A. H., A. C. Gambang, A. Sade and over exploitation because of their characteristics. S.A.Razak, (eds.). 2004. Elasmobranch resources, utilization, trade and management in Malaysia. Those characteristics make elasmobranch fishes Malaysia: Marine Fishery Resources Development should be exploited wisely. A condition when and Management Department Southeast Asian sharks are caught in their immature stages and Fisheries Development Center. 46p. the vulnerability of females on C. sorrah and S. Amorim, A. F., C. A. Arfelli, and L. Fagundes. 1998. lewini, could threat the sustainability of both Pelagic elasmobranchs caught by longliners off species in nature. Conversely, C. falciformis is southern Brazil during 1974-97: an overview. Mar. not categorized as near threatened (NT) status Freshwater Res.y 49:621- 632. because there is still not enough data to categorize Bonfil, R. 2002. Trend and patterns in world and Asian this species. However, it is not impossible for C. elasmobranch fisheries. In: S. L. Fowler, T. M. Reed falciformis to turn into threatened or even and F. A. Dipper (eds.) Elasmobrach biodiversity Mar. Res. Indonesia Vol.32, No.1, 2007: 7-19

conservation and management: Proceeding of the Davenport, S. and J. D. Stevens. 1988. Age and growth International Seminar and Workshop in Sabah, July of two commercially important sharks 1997. Gland, Switzerland and Cambridge, UK: (Carcharhinus tilstoni and C. sorrah) from IUCN-The World Conservation Union, pp. 15-24. Northern Australia. Aust. J. Mar. Freshwater Res., Branstetter S. 1987. Age, growth and reproductive 39:417-433. biology of the silky shark, Carcharhinus Demski, L. S. and J. P.Wourms. 1993. The Reproduction falciformis, and the scalloped hammerhead, and Development of Sharks, Skates, Rays and Sphyrna lewini, from the northwestern Gulf of Ratfishes Introduction, History, Overview, and Mexico. Environ. Biol Fish., 19:161-173. Future Prospects. In: J. P. Wourms and L. S. Demski Camhi, M. S., S. Fowler, J. Musick, A. Brautigam, and S. (eds.) The Reproduction and Development of Fordham. 1998. Sharks and Their Relatives - Sharks, Skates, Rays and Ratfishes. Kluwer Ecology and Conservation. Gland, Switzerland and Academic Publishers. London. 299p. Cambridge, UK: IUCN SSC Shark Specialist Group. DKP. 2003. Statistik Perikanan Tangkap Indonesia, 39p. 2001. Jakarta: Direktorat Jenderal Perikanan Carlson, J. K. 1999. Occurrence of neonate and juvenile Tangkap, Departemen Kelautan dan Perikanan. of sandbar sharks (Carcharhinus plumbeus) in the Jakarta. 94p. north-eastern Gulf of Mexico. Fisheries Bulletin., Gay, L.R. 1996. Educational research: competences 97(2), 387-391. for analysis and application. Prentice-Hall, Inc. Castro, J.I. 1993. The shark nursery of Bulls Bay, South New Jersey. 662p. Carolina, with a review of the shark nurseries of Hazin, F, A. Fischer, and M. Broadhurst. 2001. Aspect the southeastern coast of the United States. of reproductive biology of the scalloped Environmental Biology of Fishes, 38: 37-48. hammerhead shark, Sphyrna lewini, off northeastern Brazil. Environmental Biology of Cavanagh, R. D., P. M. Kyne, S. L. Fowler, J. A. Musick Fishes, 61:151-159. and M. B. Bennett. 2003. The conservation status Heithaus, M. R. 2001. The biology of tiger sharks, of Australasian chondrichthyans. Report of the Galeocerdo cuvier, in Shark Bay, Western IUCN Shark Specialist Group Australia and Oceania Australia: sex ratio, size distribution, diet, and Regional Red List Workshop, Queensland, seasonal changes in catch rates. Environmental Australia, 7-9 March 2003. The University of Biology of Fishes, 61: 25-36. Queensland. Brisbane. 170p. IUCN. 2005. The IUCN Red List of Threatened Species Clarke, S. 2004. Understanding pressures on fishery - Summary Statistics. Retrieved 9 May 2005, resources through trade statistics: a pilot study of from four products in the Chinese dried seafood market. http://www.redlist.org/info/tables/tarte3a.html. Fish and Fisheries., 5: 53-74. Krogh, M. 1994. Spatial, Seasonal and Biological Coleman, N. 1996. Australia's Sharks and Rays. NSW Analysis of Sharks Caught in the New South Wales Australia: National Book Distributors and Protective Beach Meshing Programme. Aust. J. Publishers. 61p. Mar. Freshwater Res., 45:1087-1106. Compagno, L. J. V. 1984. FAO species catalogue. Vol. 4. Lucifora, L. O., J. L. Valero, and V. B. Garcia. 1999. Sharks of the world. An annotated and illustrated Length at maturity of the greeneye spurdog shark, catalogue of sharks species known to date. Part 2. Squalus mitsukurii (: Squalidae), . FAO Fish. Synop., (125) Vol. 4: from the SW Atlantic, with comparisons with other 251-655. regions. Mar. Freshwater Res., 50:629-632. Compagno, L. J. V. 1999. Sharks. In: K E. Carpenter, and Motta, F S., O. B. F. Gadig, R. C. Namora, and F. M. S. V. H. Niem (eds.). FAO Species Identification Guide Braga. 2005. Size and sex compositions, length- for Fishery Purposes. The living marine resources weight relationship, and occurrence of the Brazilian of the Western Central Pacific. Volume 2. sharpnose shark, lalandii, , , holuthurians and caught by artisanal fishery from southeastern sharks. FAO, Rome. pp. 1193-1366. Brazil. Fisheries Research, 74:116-126. Daley, R. K., J. D. Stevens, P. R. Last, and G K. Yearsley. Oshitani, S., H. Nakano, and S. Tanaka. 2003. Age and 2002. Field Guide to Australian Sharks and Rays. growth of the silky shark Carcharhinus falciformis Australia: CSIRO Marine Research and from the Pacific Ocean. Fisheries Science, 69: 456- Development Corporation. 84p. 464. Size, Sex And Length At Maturity Of Four Common Sharks … (Fahmi & Kurnaen Sumadhiharga)

Pepperell, J. G. 1992. Trends in the distribution, species TRAFFIC. 2002. A CITES priorities: Sharks and the composition and size of sharks caught by gamefish twelfth meeting of the conference of the parties to anglers off South-eastern Australia, 1961-90. Aust. CITES. Retrieved 6 February, 2004, from http:// J. Mar. Freshwater Res., 43: 213-225. www.traffic.org/news/Sharks_CoP12.pdf. Simpfendorfer, C. 1992. Biology of tiger sharks Wetherbee, B. M., G L. Crow and C. G Lowe. 1997. (Galeocerdo cuvier) caught by the Queensland Distribution, reproduction and diet of the gray reef shark meshing program off Townsville, Australia. shark Carcharhinus amblyrhynchos in Hawaii. Aust. J. Mar. Freshwater Res., 43: 33-43. Mar. Ecol. Prog. Ser., 151:181-189. Skomal, G B. and L. J. Natanson. 2003. Age and growth White, W. T., N. G Hall, and I. C. Potter. 2002. Size and of the (Prionace glauca) in the North age compositions and reproductive biology of the Atlantic Ocean. Fishery Bulletin, 101:627-639. nervous shark Carcharhinus cautus in a large Stevens, J. D., R. Bonfil, N. K. Dulvy, and P. A.Walker. subtropical embayment, including an analysis of 2000. The effects of fishing on sharks, rays and growth during pre- and postnatal life. Marine chimaeras (chondrichthyans), and the implications Biology, 141:1153-1164. for marine ecosystem. ICES Journal of Marine White, W. T., P. R. Last, J. D. Stevens, G K. Yearsley, Science, 57:476-494. Fahmi, and Dharmadi. 2006. Economically important sharks and rays of Indonesia. ACIAR. Canberra. 329p.