CASTRO, J. I.;CLARK, E.

(JIC) National Marine Fisheries/Noaa/Mote Marine Laboratory (EC) University of Maryland/Mote Marine Laboratory 1600 Ken Thompson Parkway; Sarasota, FL 34236

Whale shark: What do we really know about it?

The maximum size of the whale shark is not known with certainty because actual measurements of large specimens are few. The largest measured specimens that we know of are a 12.1m female that stranded off Mangalore, India, and a male 12.18m from Bombay, India. Photographic evidence suggests that the whale shark may grow to a larger size. There are few reliable weights for adult specimens, given the lack of scales suitable for weighing such large animals. The weights of the 1912 Knights Key specimen often given in the literature have little or no scientific basis. Joung et al. (1996) gave the weight of a ~10.6m TL as 16,000 kg, as weighed by a construction crane. These authors also gave weights of 15,220 kg and 36,000 kg for sharks landed in Taiwan on 30 March 1994 but without adducing any other data or evidence. Whale sharks at birth range from 55 to 64 cm. The nurseries of the whale shark are poorly defined because very few small whale sharks have been captured. If the dates of capture of juveniles given in the literature are correct, newborn whale sharks can be found in summer as well as in winter, suggesting year round reproduction. The reasons for the paucity of small specimens in collection are probably the widespread nature of the nurseries in tropical waters and the unusually rapid growth of whale sharks. Remoras and cobias often accompany the whale shark. The remoras often enter the mouth, the spiracle and the anus, and sometimes they can be seen peering out of the anus.

 

UCHIDA, S.;TODA, M;KAMEI, Y.;TERUYA, H.

Okinawa Expo Aquarium, Okinawa, 905-0206 Japan

The husbandry of 16 whale sharks Rhincodon typus, from 1980 to 1998 at the Okinawa expo aquarium

From 1980 to 1998 16 whale sharks, Rhincodon typus , were kept in captivity at Okinawa Expo Aquarium, Okinawa, Japan. They were captured around Okinawa Is. by set-nets the center of which is located at 2623N, 12741E from March to September. The sea water temperature of the time captured were 21.1 to 29.0C at the depth of 20 m. Only two of 16 sharks were females and 14 were males, The mean value and range in total length and body mass were 4.8 m and 3.1 to 6.3 m, and 814 kg and 290 to 1750 kg respectively. They were kept in the Kurosio tank which is 27 m long, 12 m wide and 3.5 m deep 1,100 m3 in volume. Water parameters of the tank in mean and range were as follows : Water temperature(C) was 24.6 and 19.8 to 29.6, ph 8.2 and 7.9 to 8.35, and salinity (o/oo) 35.79 and 33.04 to 37.36. Mean and range of survival time in the tank were 502 days and 3 to 2056 days (ca. 5y 8m). The Whale sharks were fed on Euphausia pacifica, E. superba, Sergia lucens, Loligo japonica and Spratelloides gracilis once a day 6 days week. Mean feeding rates (food quantity / body mass / week x 100) of a 3.65 m female were 11.0 % in the first year of keeping, 8.5 % in the second year and 8.0 % in the third year. Mean growth per year of this shark was 29.5 cm in total length ( survival time : 2056 days) , 4.5 m male shark 21.6 cm (1040 days) and 4.85 m male 25.5 cm (458 days) respectively. Feeding and other behaviors in tank are reported.

 

ECKERT, S. A.;DOLAR, M. L. L.;KOOYMAN, G. L.;PERRIN, W. F.;RAHMAN, A. R.

(SAE) Hubbs Sea World Research Institute, 2595 Ingraham St., San Diego, CA 92109; (MLLD) Silliman University, 6363 Lakewood St., San Diego, CA 92122 , USA; (GLK) Scholander Hall, Scripps Institution of Oceanography, University of California San Diego, CA; (WFP) Southwest Fisheries Science Center, U.S. National Marine Fisheries Service, P.O. Box 271, La Jolla, CA. ; (RAR) Head, Borneo Marine Research Unit, Jalan Tuaran, Campus, Universiti Malaysia, Sabah, Locked Bag 2073, 88999 Kota Kinabalu, Sabah, East Malaysia.<O:P</O:P

Are the whale sharks (Rhincodon typus) of Southeast Asia resident or migratory?

Movements of individual whale sharks (Rhincodon typus), are almost unknown. Recent studies from the Sea of Cortez, indicates that whale sharks are highly mobile and may range for thousands of kilometers. However, most information on distribution is related to seasonal occurrences based on anecdotal reports of occasional sightings. This lack of information on basic biology, especially movement and migration patterns is a problem for resource managers, as the species is increasingly utilized for ecotourism and commercial harvest. The latter use had become particularly intense in the Philippines, where an unregulated harvest burgeoned in response to a dramatic increase in the market for whale shark meat and fins in Taiwan. Catches had fallen steeply despite increasing fishing effort and rising prices. In January 1998 we initiated an international cooperative research program with the Borneo Marine Research Unit of the Univ. of Malaysia, Sabah, the Marine Laboratory of Silliman University, Dumaguete, Philippines; and the World Wildlife Fund-Philippines to determine if the whale sharks observed in the greater Sulu Sea region are resident or migratory. Using satellite telemetry we monitored the movements of whale sharks from the greater Sulu Sea region for up to 4 months. Results of this study will be presented.<O:P</O:P

YAPTINCHAY, A. A.;*ALAVA, MOONYEEN N. R.<O:P</O:P

World Wildlife Fund - Philippines,23 Maalindog St., UP Village, Diliman, Quezon City 1101

Philippines community-based whale shark conservation and ecotourism development

Report on a whale shark aggregate in Donsol, Sorsogon (southern Luzon) in January 1998 led to the discovery and promotion of the area as a potential whale shark ecotourism site. Media coverage of this discovery led to tourist influx to an ill-equipped community as well as hunters' encroachment to the site which otherwise had no history of hunting. The municipal waters of Donsol were protected by a local ordinance establishing the site as a whale shark sanctuary in early March 1998. Despite this ordinance, seven whale sharks were poached in the area. This raised a national alarm which ultimately led to the estbalishment of a Fishery Administrative Order (FAO) 193, also called as the Whale Shark and Manta Ray Ban, in late March 1998. WWF-Philippines was invited to help establish the whale shark exotourism activity and through a consultative effort with stakeholders, the Donsol Whale Shark (Butanding) Ecotourism Management Plan was developed, with financial support from UNDP. A tri-partite agreement was drawn up involving the local government of Donsol, a local NGO (Donsol Municiapl Torusim Council), and WWF-Philippines. The whale shark interaction tourism in Donsol has been operational for two seasons and tourism statistics is presented for 1998 and 1999. Tourism as an economic alternative to hunting has been proven to be successful. This strategy is able to support community development, conservation, and the tourism industry as well as provide a multitude of venues for increased appreciation of natural resources, protecting habitats and threatened species. However, politicial rivalries and administrative problems have blighted tourism management itself.<O:P</O:P

 

NORMAN, B.

City West Lotteries House 2 Delhi Street West Perth Western Australia 6005

Whale shark conservation via a collaborative approach

An ecotourism industry revolving around the whale sharks (Rhincodon typus) at Ningaloo Marine Park, Western Australia has been operating since 1993. A study aimed at determining how to minimise the impacts of ecotourist interactions on these sharks has been underway since 1995. This research was possible through the combined efforts of industry, government management agencies, Murdoch University and Australia's leading non-government marine conservation group - the Australian Marine Conservation Society (AMCS). Suggested amendments to some of the ecotourism management guidelines were tested during the 1999 'season', with excellent results. Through the development of a whale shark photo-identification library, it was possible to identify sharks that had returned to the same location on the northwest coast of Australia between 1995 and 1999. It is likely that sharks from Australian waters may migrate to areas where they active hunting is permitted. It is suggested that at the current level, fishing pressure on whale sharks is unsustainable. AMCS are currently coordinating a collaborative effort to encourage nations to ban the hunting of this species and work towards greater global conservation for the largest living shark.

 

ANTONIOU, A.

Shark Research Insitute, P.O. Box 40, Princeton, New Jersey 08540

Aggregations of whale sharks (Rhincodon typus) occur each year off South Africa (Indian Ocean) and in the waters surrounding Utila, Bay Islands Honduras (Caribbean Sea) where they form the basis of an ecotourism industry

In 1998 and 1999 the Shark Research Institute deployed satellite tags on 5 whale sharks in an effort to gather information on their long term and short term movements. Problems were encountered with the attachment of the tags to the sharks. Satellite tags were attached to the sharks by divers and various tag-anchors were utilized with varying degrees of success. Tethered tags were attached by divers and a variety of tag-anchors were utilized. Data received so far is encouraging, which will enable us to drawn a picture of the day to day life of a whale shark.<O:P</O:P

 

GRAHAM, R. T.;HEYMAN, W. D.;KJERFVE, B.<O:P</O:P

(WH) 62 Front Street, Punta Gorda, Belize, (BK) Department of Geological Sciences and Marine Science Program, University of South Carolina, Columbia, SC 29208, USA.

Population size estimates of whale sharks, Rhincodon typus, off the Belize Barrier Reef

At least 6 sites where whale sharks aggregate predictably are recorded for the Indo-Pacific and Pacific Oceans, whereas the literature reports none, save occasional sightings, for the Atlantic Ocean. Following an investigation of local fishermen's reports, we document here a new aggregation site and possible centre of distribution of whale sharks Rhincodon typus in the Caribbean, on the Belize Barrier Reef. Gladden Spit, a promontory on the barrier reef harbours a dense and predictable aggregation of whale sharks that feed on the freshly released gametes of large spawning aggregations of 2 Lutjanid species during the full moon periods from April to June. A preliminary survey of the population in 1998 based on individual markings and scars yielded an estimated population of 25 individuals. A tagging programme undertaken in 1999 identified 15 sharks. Combined with a mark release recapture study undertaken in 1999, that also accounted for sighted but untagged sharks, the population is estimated at a minimum of 23 individuals. Mean tail length (TL) of tagged whale sharks was 5.05 m. Although the sex ratio could not be determined with confidence, only one shark possessed the TL to qualify it as sexually mature. Tagged individuals from the May full moon were re-sighted feeding during the June full moon indicating tag retention and site fidelity at Gladden Spit during the snapper spawning-season. Following this period, tagged whale sharks were re-sighted north, south, and east of the aggregation site outside the barrier reef in deep water, associated with schools of bonito, blackfin, bigeye, and skipjack.<O:P</O:P

 

*HEYMAN, W. D.;GRAHAM, R. T.;KJERFVE, B.

(DWH) The Nature Conservancy, 62 Front Street, Punta Gorda, Belize; (RG) Environment Department, University of York, Box 170, Punta Gorda, Belize,; (BK) Department of Geological Sciences and Marine Science Program, University of South Carolina, Columbia, SC 29208, USA,<O:P</O:P

Whale sharks feed on gametes released from snapper spawning aggregations in Belize

Whale sharks (Rhincodon typus) are considered opportunistic planktivores, whose diet includes nektonic prey such as squid and small fry. They are commonly known to target dense patches of their prey. Here we report the first direct observations of whale sharks feeding on the freshly released gametes of reef fish in large spawning aggregations. This food source attracts the densest and most predictable aggregation of whale sharks ever reported with 25 individual whale sharks recorded in less than a 100m diameter area. Over 126 hours of underwater observations made during the April-June full moon periods in 1998 and 1999 indicate that whale sharks aggregate to feed at dusk on the spawn of two reef snappers, Lutjanus cyanopterus and L. jocu. Several additional species of finfish are also thought to spawn at Gladden Spit during this season, including mutton snappers (L. analis), and Carangids Caranx ruber and C. hippos. Scuba observations of these seasonally aggregating finfish in proximity to whale sharks, and gonadal analysis of captured fish, indicate that their spawn may also be targeted by feeding whale sharks. Whale shark feeding on spawning snapper has implications for traditional snapper fisheries, predictable whale shark visitations, and the burgeoning whale shark tourism at the site.

 

*CHILDS, J.;BURKS, C. M.;MULLIN, K. D.;HEWITT III,

(JC) Center for Coastal Studies, Texas A&M University-Corpus Christi, 6300 Ocean Dr Nrc 3200, Corpus Christi, TX 78412; (CMB;KDM) Southeast Fisheries Science Center, NMFS/NOAA, Mississippi Laboratories, P.O. Drawer 1207, Pascagoula, MS 39568-1207; (JH) Aquarium of the Americas, #1 Canal Street, New Orleans, LA 70130

The occurrence and distribution of the whale shark (Rhincodon typus) in the northern Gulf of Mexico

The whale shark (Rhincodon typus) frequents the northern Gulf of Mexico, however, little is known regarding its seasonal distribution, abundance, and behavior in the region. This paper present the occurrences of whale sharks in the northern Gulf of Mexico, gathered using three different survey methods (aerial, underwater, and offshore platform). Data presented using geographic information system technology illustrates the seasonal distribution of whale sharks in the region, including strong evidence of seasonal habitat use of neritic waters in the northern Gulf during warmer months. The occurrence of whale sharks associated with topographic high communities and mass spawning events in the northern Gulf are also examined.

15/06/2000 - 03:45:00 PM - Salon Madre Perla

 

LOZANO, A. R.

Baja Quest, Scuba Diving and Adventure Travel Service & NIPARAJA A.C. - Environmental Group, La Paz, B.C.S. C.P. 23060, Mxico

A proposed management program for the whale sharks Rhincodon typus of La Paz Bay, B.C.S.

Recorded whale shark (Rhincodon typus Smith, 1828) sightings during the last 5 years show that aggregations occur in La Paz Bay at specific locations during seasonal plankton blooms. The sites are currently well known by the local dive operators and other outdoor service providers. The relatively predictable presence of the sharks in the proximity of the city has increased the number of tourists who come to La Paz to interact with the whale sharks. Even though whale sharks are not commercially fished in Mexico, the increased tourism may generate detrimental impacts to the whale sharks feeding or migration patterns. The presence of whale sharks represents economic revenue for La Paz tourism industry and an ideal location for research and monitoring of their biology and ecology. Very little is known about the abundance, distribution and reasons why they aggregate in La Paz Bay, consequently, tourism impacts are difficult to estimate. This paper suggests a precautionary approach to manage the area where whale sharks seasonally occur. The program's objectives are to provide guidelines for sustainable human-whale shark interactions and to implement a monitoring program that will generate scientific information. The proposed management program takes into consideration the Mexican authorities' environmental regulations and their criteria for protected areas.

15/06/2000 - 04:00:00 PM - Salon Madre Per

 

KETCHUM, J. T.;LOZANO, A. R.

(KJT) Museo de Historia Natural, Universidad Autnoma de Baja California Sur. Carretera al sur, km 5.5, La Paz, B.C.S., C.P. 23080, Mexico., (LAR) Baja Quest & Niparaja, A.C., La Paz, B.C.S.

Observations on the seasonal occurrences of whale sharks (Rhincodon typus Smith, 1828) in the southern Gulf of California

Historical records of whale sharks in the Gulf of California are anecdotal and unreliable for the most part. In spite of recent reports of whale sharks associated with seasonal plankton blooms in the Bay of La Paz, formal studies on their distribution and abundance within the Bay and neighboring areas are almost non-existent. For this reason, a five year survey on whale shark occurrences started since 1995 in the Bay of La Paz and neighboring islands such as San Jose, Espiritu Santo and Cerralvo, plus offshore islets and seamounts. A spotter plane and different vessels were used in order to search these areas during the plankton bloom seasons (May-June and October-November). During each sighting information such as location, size, sex, markings and behaviour of each individual were recorded by swimming close to each animal both free-diving or by using SCUBA. Our observations indicate that younger animals occur more commonly feeding on plankton blooms closest to the coastline in the Bay of La Paz, whereas older animals tend to appear non-feeding in offshore areas such as El Bajo and east of Espiritu Santo island. The locations with the highest number of occurrences were the area between the phosphate mine in San Juan de la Costa and Punta Mogote, and El Bajo seamount. Overall, females were larger, especially those apparently pregnant seen in offshore areas, and more abundant than males in all locations. The continuity of studies such as these will help to build a solid background for future studies on population and migratory patterns of whale sharks in the area, that will ultimately support conservation and managememt efforts for this species in the Gulf of California.

 

NELSON, J. D.;ECKERT, S. A.

(DJN) University of San Diego, Department of Marine and Environmental Sciences, 5998 Alcala Park, San Diego, California, 92129 USA; (ASC) Hubbs-Sea World Research Institute, 2595 Ingraham St.; San Diego, California, 92110 USA University of San Diego, Department of Marine and Environmental Sciences 5998 Alcala Park, San Diego, California, 92129 USA

Local habitat distribution and utilization of whale shark (Rhincodon typus) within Bahia de Los Angeles, B.C.N., Mexico<O:P</O:P

Although the whale shark (Rhincodon typus) is the world's largest fish, the species has been the subject of very limited scientific study and much of this elusive creature's natural history is unknown. This project seeks to understand how the whale shark utilizes coastal ecosystems. Field research was conducted in Bahia de Los Angeles, B.C.N., Mexico, from July 28, 1999 through October 26, 1999. Research focused on movements and locations of observed whale sharks and feeding within the bay. Over 170 whale shark sightings were recorded, from which 19 individuals were identified. Several individuals (6) were tracked using VHF radio telemetry for periods of up to two weeks. Data collected included size, sex, distinguishing marks, behavior of the animal, as well as weather and water conditions. Sixteen plankton stations within the bay were sampled regularly throughout the field season. Samples were also taken during observed feeding events. Over 200 plankton samples were analyzed. The composition and densities of plankton samples taken during active feeding events were compared to the composition and densities of plankton samples taken from stations throughout the bay. Analysis of shark movements as they relate to plankton abundance/composition will be presented.

 

O'SULLIVAN, J. B., Mitchell, T.,

Monterey Bay Aquarium 886 Cannery Row, Mtry. CA.

Discover Baja , S.D. CA

A fatal attack on a whale shark Rhincodon typus, by killer whales Orcinus orca off Bahia de Los Angeles, Baja California

In July of 1992 two killer whales Orcinus orca attacked, killed and fed on an 8-meter whale shark Rhincodon typus in the waters off Bahia de los Angeles. Throughout most of the year both of these species are common inhabitants in the Gulf of California, yet until this time there had been no observations on this behavior to date. Besides the activities of man, few predators have been speculated that have the ability to take the young, juveniles or adults of this species. A discussion on the need for regulations for the protection of this species from human activities in the waters of Mexico will be discussed.

 

 

TORRES, D. S.; LIM, I. A.; REYES, C. T.; NARIDA, E.

(STD; ALI) Dos Palmas Research Center, Arrecife Island, Barangay Manalo, Puerto Princesa City. (TRC; NE) Palawan Geographic Society, Lacao St., Puerto Princesa City.

Notes on the characteristics of whale sharks (Rhincodon typus) in Honda Bay (Palawan, Philippines)

Whalesharks were observed in Honda Bay from September 1999 to January 2000 through more than 60 research interactions using six types of observation platforms. No evidence of tags or tag scars were observed suggesting this whaleshark grouping has not been previously studied. Claspers were detected only on one whaleshark suggesting conformity with sex-segregation observed for other elasmobranchs. Modal class length was 4.4 - 5.6 meters (15-19 feet) suggesting conformity with size-segregation reported for other shark species. A maximum of nine whale sharks occurred simultaneously in two sightings (Sept. 21, 1999 and October 10, 2000). Sightings aggregated at a 40 km2 region adjacent to the 20-fathom isobath. Vertical feeding using active suction mechanism was a common foraging strategy. Whalesharks formed foraging assemblages with up to hundreds of birds and thousands of fishes indicating intense ecological processes in regions where whalesharks were encountered. Photo- and video-record analysis can identify at least twelve individuals, thus providing evidence for temporal segregation and shifts in individual composition through time. Six negative human-whaleshark interactions were recorded, two of which were fatal. These are: (1) deep cut across the left dorsal, anterior; (2) right pectoral amputated by straight, sharp object; (3) fishing gear fragments entangled on caudal peduncle; (4) scarring; (5) fatal entanglement in drift gill net; and (6) directed take. Government inspectors intercepted 829 kg of whaleshark meat in Puerto Princesa City Airport and are filing appropriate charges. Information generated enabled interested individuals and institutions in adjacent communities to initiate, coordinate and prepare conservation action plans addressing whaleshark related issues.