A Study of Sri Lanka's Manta & Mobula Ray Fishery

Transcription

1 P a g e 1 A Study of Sri Lanka's Manta & Mobula Ray Fishery September, 2011 RESEARCHER Daniel Fernando Lead Scientist, Sri Lanka Manta Trust SRI LANKA +94 (0) daniel@mantatrust.org SUPERVISOR Guy Stevens Director Manta Trust Landaa Giraavaru, Baa Atoll REPUBLIC OF MALDIVES guy@mantatrust.org

2 P a g e 2 Overview Sri Lanka is a small island nation off the southern coast of the Indian subcontinent, surrounded by the Indian Ocean, the Gulf of Mannar and the Palk Strait. It has a population of just over 21 million inhabitants, with a significant proportion living along the 1,770 km stretch of coastline. Fish products are an important source of protein (55 percent of total animal protein consumed by the population) and contribute around 1.5 percent to GDP (Sri Lankan Department of Fisheries and Aquaculture Resources, 2007). The Sri Lankan Exclusive Economic Zone (EEZ) covers an area of 517,000 km 2 and includes vital shipping lanes connecting West Asia and Europe to South East Asia and the Far East. Fishing is an integral part of the Sri Lankan culture it employing over 650,000 people. The fishing industry consists of three primary sectors: coastal fisheries, off shore/deep sea fisheries and inland and aquaculture fisheries. In 2007, these sectors earned US$ 173 million through exports (Sri Lankan Department of Fisheries and Aquaculture Resources, 2007), with the coastal fisheries contributing 165,320 metric tons and the offshore and deep sea fisheries contributing 109,310 metric tons. The Sri Lankan government is also keen to increase the national fishing productivity with the provision of subsidies for fuel and boats and the establishment of new fishery harbors, fish processing and canning factories and the introduction of trawlers to engage in deep sea trawling (Mahinda Chintana 2005 Election Campaign by the President of Sri Lanka). Coastal and deep sea fishing takes place all around Sri Lanka and is affected by both the South-West and North-East Monsoons due to the geographical location of Sri Lanka; between latitudes 5 and 10 N, and longitudes 79 and 82 E. The South-West monsoon generally occurs from June until October, while the North-East monsoon lasts from November until March. Depending on migration patterns of marine species, catches of certain species may increase or Sri Lanka and the Indian Ocean decrease between the two monsoons. However, fishermen also tend to change their fishing patterns with the monsoons, occasionally travelling to the other side of Sri Lanka, or further afield for more favorable conditions. For many species this often tends to result in similar levels of catches observed throughout the year at the markets.

3 P a g e 3 Contents Page Sri Lankan Manta Project (Page 4) Fish Market Overview (Page 5-7) Fishing Techniques & Fishing Grounds (Page 8-9) Data Collection (Page 10-11) o Negombo Fish Market o Mirissa Fish Market o DNA Sampling Catch Summary (Page 12-14) o Spine-tail Devil Ray - Mobula japanica o Sickle-fin Devil Ray - Mobula tarapacana o Bent-fin Devil Ray - Mobula thurstoni o Oceanic Manta Ray - Manta birostris Market Value & Trade (Page 15-19) o Meat Trade o Gill Raker Trade Sri Lanka's Annual Mobulid Ray Landings (Page 20-21) Discussion & Conclusions (Page 22-25) o Fishery Impact o Nursey Ground o Gill Raker Trade o Conclusions o Future Work Additional Information (Page 26-27) Aknowledgements & Thanks (Page 28) References (Page 29)

4 P a g e 4 Sri Lanka Manta Project During the months of May to August 2011, surveys were conducted at the Negombo and Mirissa fish markets in order to evaluate the extent of the manta and mobula ray fishery of Sri Lanka. The number of each species encountered was recorded, along with their gender and sexual maturity. DNA samples of species of interest were also collected and additionally disc width and body length measurements taken for all manta specimens. Disc widths were also recorded for specimens of mobula species when time permitted. Interviews were conducted with both fisherman and market dealers to establish the catch methods, fishing grounds, seasonality, market values and product usage of the species caught. Information on the processes surrounding the preparation and exportation of particular parts of mantas and mobula Locations of the Negombo and Mirissa Fish Markets in Sri Lanka were also collected and an estimation of the total yearly catch and monetary value of this fishery within Sri Lanka as a whole was calculated. A Scientist measuring a dead Oceanic Manta Ray (Manta birostris) at a fish market in Sri Lanka

5 P a g e 5 Fish Market Overview A total of 2,026 specimens were recorded at both the Negombo and Mirissa fish markets during the months of May through August, 2011 (totaling 75 survey days). Of these 2,026 specimens, detailed records (Disc Width; DW, and Body Length; BL) were documented for 569 specimens. The observed species in order of frequency were Mobula japanica, Mobula tarapacana, Manta birostris and Mobula thurstoni. Negombo Fish Market The Negombo market landed the largest number of specimens and the majority of boats supplying this market are multi-day vessels (7 days up to around 45 days) which would arrive the previous night and unload their entire catch at the market in the morning (between 03:00 am and 06:00 am). Their primary fishing grounds serving the market were in the West and North-West of Sri Lanka, Multi-day vessels at the Negombo Fish Market with some boats going to the Western coast of Southern India. Occasionally during the South-West Monsoon boats would also fish the East coast of Sri Lanka, either landing their fish in Trincomalee (selling at the market there or sending it over-land to the Negombo market), or coming by boat around Sri Lanka (usually only if a full catch). The catches from these boats are comprised primarily of tuna, sharks, billfishes, mobula and manta rays. On most mornings there are several trucks that have brought sharks, tuna and mobula from other fish markets in the country, particularly from the Eastern coast. Landings at the Negombo market generally sell at higher prices due to the large number of dealers and exporters that buy fish at this market. This market also seems to land some of the highest numbers of sharks in the country and there appears to be a well established shark fin trade. The gill raker dealers at this market specialize and focus on only manta and mobula rays. Mobula and manta are generally auctioned whole to these dealers. Piles of sharks and mobulas at the Negombo Fish Market

6 P a g e 6 There is also a smaller retail fish market across the road, where one-day or 12-hour boats land their catches (mostly reef fish, cuttlefish, prawns, crabs, with the occasional small ray). Some trucks from other parts of the country may also bring their fish (including rays) to this retail market. In addition to these sources, mobula (and rarely manta) that are sold across the road at the whole-sale market may be brought to be sold at this retail market. Marlin at Mirissa Fish Market The fishermen at the market are mostly Catholics, which means that the market is open throughout the year with the exception of Sundays, Catholic holidays and on days when there are Church feasts in the villages of the fisherman. Mirissa Fish Market The Mirissa fish market also receives both daily and multi-day vessels (7 days up to around 60 days) every morning (from 05:00 am until around 08:00 am). However, unlike the Negombo fish market, they may not unload their whole catch at once, but rather over two or three days in an attempt to keep the prices high. The smaller daily boats unload their entire catch immediately and often bring in complete manta or mobula (without gutting). Rotten M. tarapacana at Mirissa Fish Market Their primary fishing grounds are in the South of Sri Lanka and toward the South-East, occasionally venturing as far as Indonesia. Their catches comprise mostly of tuna, sailfish, marlin, sword fish, mobula, manta and some sharks. Most boats in Mirissa carry harpoons, which they claim to use if they see manta or mobula swimming at the surface (only two recorded incidents so far). Mirissa has a history of harpooning dolphins (prior to the ban on the fishing of marine mammals). The overall quality (freshness) of the fish (including manta and mobula) landed at Mirissa is lower than at Negombo. This is due to longer average vessel times at sea and because the catch is often not unloaded immediately upon returning to port. Furthermore, at the end of their fishing trips the Mirissa boats generally have much less remaining packing ice in their boat's hold when compared to the Negombo boats, further adding to the degradation of the catch quality. Smaller M. birostris sold in halves

7 P a g e 7 There are occasionally some dealers that buy whole mobula and transport them to Negombo by truck, in order to re-sell at a higher price. The gill raker dealers at this market often specialize in sharks and mobula/manta as well as marlin, swordfish and sailfish. The manta or mobula are sold in halves, or sometimes the wings as one part, and the head as another. Fresh mobula meat is not sold at local retail markets in the Mirissa area due to lack of local demand, but instead is transported to other areas of the country; coastal or hill country (central Sri Lanka). However, this is only done if the meat is fresh and in most cases it is old and therefore sorted for drying together with other fish (waste pieces, or M. thurstoni at the Negombo Fish Market caught near Indonesia rotten fish). The final dried product, locally called dried fish is consumed throughout Sri Lanka, either as flakes or chunks in local cuisine. This dried-fish does not exclusively contain mobula meat and the end-of-the-line customer will not know whether or not the dried-fish actually contains any manta or mobula meat. The fishermen and dealers at this market are mostly Buddhists, so the market is open on all days except full moon days (Poya days) and other Buddhist holidays.

8 P a g e 8 Fishing Techniques & Fishing Grounds Interviews with the fisherman have indicated that almost all manta and mobula are caught as bycatch in gill-nets. Additionally, the majority of the rays caught are still alive when brought on to the boats and only die when cut in half in order to fit them into the ice hold of the boat. The boats from Mirissa usually carry harpoons on board, but the last four months of research have not revealed a death by harpoon yet (only two recorded instances over the last one year). Generally both Negombo and Mirissa fishermen state that if they see a lot of mobula or manta, they do not lay their nets as they get badly entangled when mobula or manta are caught. This entanglement would result in a lot of lost time spent freeing up the nets and repairing any damages. There is also the potential for the entire net to be lost as mobula often swim in aggregations and can be too heavy for the nets, which sink under their accumulated weight. The fishermen maintain that this is Gill nets used by the fishermen another reason why they have to pull the nets in quickly, since if mobula are caught, it is easier to bring the nets on board when they are still alive (which means that they must sink when dead). In the unusual case of a large manta getting caught, they may even simply tow the nets behind the boat as it may be too strenuous to attempt to haul the manta on board and kill it. Fishermen report rare cases of a manta being brought to the market while still alive, towed behind a boat. The fishermen also claim that mantas and mobulas melt the ice in the hold much faster than other types of fish. This means that they do not like to catch them at the beginning of a fishing trip, but rather on the way back to the harbor. Catches early in the trip are often discarded/released (alive or dead). They also allege that pregnant mantas and mobulas are released if still alive and that young mobula are only caught in the nets if they are in a rush or panic. Fishermen also say that the seasons do not seem to influence the catching of mobula rays, but do influence the numbers of manta rays that are brought in. The numbers are generally said to increase during the South-West monsoon (June until end of September). However, this year the monsoon appears to be arriving late and described seasonal increases may not be reflected in the acquired data. Furthermore, a lot of fishermen also claim that the manta and mobula catches increase significantly with the presence of krill. They say this can attract manta Krill taken from the stomach of M. Japanica in Sri Lanka

9 P a g e 9 rays at any time of the year, regardless of the monsoon direction. They also believe that manta rays live at great depths and only migrate upwards when there is krill near the surface. Fishermen in Sri Lanka often travel great distances to reach the most productive fishing grounds. Many claim that the Sri Lankan waters are already over-fished, so they venture into International Waters or sometimes into the EEZ of neighboring countries, such as India, the Maldives and Indonesia. They used to venture as far as the Seychelles and Madagascar; however, the recent issues with piracy in Somalia prevent them from going in to those particular areas. Fishermen at Negombo have mentioned that the Chagos Archipelago (now the largest marine reserve in the world) is particularly good for shark fishing, although the penalties of getting caught in those waters make fishing these waters a risk business. The fishermen also have a tendency to fish the same area, particularly from Mirissa (see below map), as they use the GPS coordinates made available by the meteorological department (which are provided from NARA - National Aquatic Resources Research and Development Agency), indicating potentially productive fishing grounds. Map indicating primary Mobulid Ray fishing grounds GPS coordinates obtained by interviewing the skippers of the vessels at the markets. Coordinates with yellow icons (North-West and South- West; close to Maldives) are coordinates obtained at Negombo market, while all remainder are from Mirissa.

10 P a g e 10 Data Collection Species Negombo Fish Market: Number of Specimens Recorded May (10 days) June (10 days) Month July (10 days) August (10 days) Total (40 days) Daily Average M. birostris M. japanica M. tarapacana M. thurstoni All spp Extrapolating these values to a yearly basis Taking into account 26 public holidays (less or no fish sold) and 52 Sundays (market closed): 287 days in the year. Species No. of specimens per year M. birostris M. japanica M. tarapacana M. thurstoni All spp

11 Species Mirissa Fish Market: Number of Specimens Recorded May (5 days)* June (10 days) Month July (11 days) August (9 days) Total (35 days) P a g e 11 Daily Average M. birostris M. japanica M. tarapacana M. thurstoni All spp * Only 5 days were surveyed as the other 5 were spent in Trincomalee (data from Trincomalee was not included as there was no proper central market. This location was not surveyed again for this project). Extrapolating these values to a yearly basis Taking into account 26 public holidays (less or no fish sold): 339 days in the year. Note; Mirissa market does not close on Sundays. Species No. of specimens per year M. birostris M. japanica M. tarapacana M. thurstoni All spp Total Number of DNA Samples Collected at both Fish Markets Species No. of DNA samples collected M. birostris 37 M. japanica 194 M. tarapacana 106 M. thurstoni 19 All spp. 356

12 P a g e 12 Catch Summary The majority of specimens recorded were M. japanica (n=1739), followed by M. tarapacana (n=224), M. birostris (n=40) and finally M. thurstoni (n=21). Spine-tail Devil Ray - Mobula japanica The recorded specimens of M. japanica totaled 611 females, 295 immature males, 413 mature males and 420 unknowns. The largest recorded specimen (female) had a DW of 252 cm. The smallest M. japanica recorded was a female with a disc width of 60 cm and body length of 28 cm. The fisherman reported that it was entangled in the nets and was not removed as a fetus from inside a pregnant female. There was only one recorded specimen that was taken from a pregnant female and it had a DW of 71 cm. The average DW was cm. Sickle-fin Devil Ray - Mobula tarapacana

13 P a g e 13 Catches of M. tarapacana comprised of 101 females, 43 immature males, 39 mature males and 41 unknowns. The largest specimen (male) had a DW of 314 cm. The smallest specimen had a DW of 138 cm. The average DW was cm. Only 56% (n=127) of the surveyed tarapacana specimens were measured as this species is usually landed already cut into more than two pieces, making measurements difficult and inaccurate. Bent-fin Devil Ray - Mobula thurstoni Of the recorded M. thurstoni, 10 were females, 5 immature males, 3 mature males and 3 unknowns. The largest recorded specimen had a DW of 168 cm, while the smallest a DW of 64 cm. The average DW was only cm, which is considerably smaller than the recorded maximum DW of 220 cm. Furthermore, it is interesting to note that the average size (DW) of M. thurstoni caught in waters close to Sri Lanka was only cm, while the 6 recorded M. thurstoni caught by a Sri Lankan boat close to Indonesia had an average DW of cm.

14 P a g e 14 Oceanic Manta Ray - Mobula birostris The M. birostris specimens included 16 females, 21 males and 3 unknowns. The largest had a DW of 414 cm (mature male), while the smallest a DW of only 177 cm (immature male). The average DW was cm, which is a lot smaller than the recorded maximum of 680 cm in scientific literature. There was a reported catch of two large manta rays at the Galle fish market and these appeared to be over 500 cm, however such cases seem to be quite rare. Out of the total number of measured M. birostris observed at the markets (n=40), based on the conservative assumption that a mature M. birostris has a disc width (DW) greater than 350 cm, the vast majority of all the specimens were juveniles or immature adults (n=38): Negombo: Of 27 specimens measured, 25 were immature sub-adults or juveniles Mirissa: Of 13 specimens measured, all 13 were immature sub-adults or juveniles

15 P a g e 15 Market Value & Trade (Local Consumption and Export) The driving revenue generated from the mobulid fishery in Sri Lanka is divided among a number of traders in several countries. The general flow is as follows: Fishermen Gill Raker Dealers Exporters Importers Retailers Sri Lanka Asia Interviews at the markets have indicated that the business of exporting gill rakers is fairly new. There has been a demand over the last 10 to 15 years, but it has only been in the last 3 to 5 years that the demand has greatly risen and that the prices paid for rakers has increased. This could be due to the growing economy of China (primary buyers of rakers) allowing larger numbers of people to afford traditional medicine that was perhaps previously only available to the exclusive upper classes. Another contributing factor might be the collapse of other mobulid fish stocks in other parts of the world that may have been supplying China (e.g. Indonesia). On a more local level, it could simply be an attempt to diversify into new fisheries as the traditional and more desirable fish stocks are depleted (i.e. sharks, tunas and billfishes). Additional interviews conducted with both fisherman and gill raker dealers at the Mirissa and Negombo fish markets revealed that while the fisherman on the boats do not earn much, or benefit greatly from the fishing of mobula/manta, the small number of gill raker dealers and exporters seem to be profiting considerably within Sri Lanka. Once the mobula or mantas are landed at the markets, they are generally bought by gill raker dealers or dry fish dealers. In the latter case, the heads of the rays are then bought by the gill raker dealers at the market itself. Occasionally, at markets such as Mirissa, there are whole-sale buyers that may purchase whole mobula (rarely manta and usually with heads) to transport and sell at another larger market (generally the Negombo market). Meat Trade The meat (consisting of wings and posterior part of body) from the mobula rays is generally bought and sent to the smaller retail markets to be re-sold on a per/kg basis to individual buyers. This is of course done only with fresh meat. The meat of M. tarapacana fetches the highest prices, followed by M. japanica, while M. thurstoni is considered similar to M. japanica Dried mobula meat and only results in lower prices due to their general smaller size. The meat of M. birostris is rarely sold for immediate human consumption, instead it is dried to be sold as low quality dried fish or used as animal feed (chicken and shrimp farms), as the dealers and fishermen say that manta meat has a sandy or grainy texture.

16 P a g e 16 Fresh mobula meat sold locally at retail markets Meat that has gone off (identified by the color of the meat or by smelling a sample) is bought, dried and also later sold as dry fish used in local cuisine, or for farm animal fodder. The drying of this meat may take place on a large scale, generally on beaches with good sun, or on a small scale, such as a dealer s private house (on his roof or backyard). If the meat is quite fresh, the gill raker dealers themselves may purchase the entire mobula, keep the head and sell the rest to small retailers. The rotten Mobulid rays are generally bought by the dry fish dealers who then sell the heads to the gill raker dealers. In some cases the gill raker dealers may also have a small side business selling dry fish. At the Mirissa market, the mobula rays are sold in halves (or more pieces if large individuals). For an average sized mobula (M. japanica) in Sri Lanka (DW: cm) the price of one half is around Rs. 2, (US$ 22.80) up to around Rs. 3, (US$ 34.66). The prices are similar at the Negombo market, where the rays are sold as whole individuals. The other main species of mobula is M. tarapacana, which sells for around Rs. 5, (US$ 45.60) to around Rs. 20, (US$ ) for entire individuals. Mobula meat processing site; the rays are filleted, salted and dried Piles of mobula at Negombo Fish Market These higher prices reflect the general larger size of this species of mobula and the fact that the meat is more highly valued. The prices rise and fall depending on the freshness of the meat and the size of the catches on a particular day (or from previous days). There are also circumstances when mobulas are sold on a per/kg basis to the dealers. This occurs when large numbers of mobula are landed. The price ranges from around Rs (US$ 1.28) per kg up to around Rs (US$ 1.46) per kg for mobula rays and around Rs (US$ 0.91) per kg for manta rays (which get dried). The retailers at the smaller markets purchase fresh mobula meat from the whole sale markets and sell it on at prices ranging from Rs (US$ 2.01) per kg to Rs (US$ 2.37) per kg.

17 P a g e 17 Averaged Value of Manta and Mobula Ray Species Species Average size of individual (DW) Cost of average sized whole individual Approximate value of meat per kg M. birostris cm Rs. 4, (US$ 40.93) Rs (US$ 0.91) M. japanica cm Rs. 3, (US$ 28.20) Rs (US$ 1.36) M. tarapacana cm Rs. 11, (US$ ) Rs (US$ 1.64) M. thurstoni cm Rs. 1, (US$ 10.00) Rs (US$ 1.36) Gill Raker Trade The gill rakers are the driving force behind this fishery. Although they comprise just a tiny percentage of a manta or mobulas mass, they sell for significantly more than the rest of the body parts put together. Manta ray gill rakers fetch the highest prices, followed by the mobulas (generally M. tarapacana and then M. japanica and other mobula species), with the price reducing as the size of the rakers decreases. Therefore, a large manta may fetch a very high price, even though the meat would only be sold as low quality dried fish. This high value of the mantas rakers at the Wet Gill Rakers - from left to right: M. japanica, M. birostris & M. tarapacana markets is quite apparent. For example, a manta with a DW of 220 cm at Negombo market typically sells for around Rs. 3, (US$ 27), while a manta with a DW of 392 cm would sell for around Rs. 25, (US$ 228). This tenfold price increase is due to the considerably larger, and disproportionately more valuable gill rakers found inside the larger animal. There have however been a few recorded instances (mostly at the Mirissa fish market), where fishermen have discarded the mobula heads at sea only bringing the meat of the Mobulid rays to the market for sale. These fishermen did not realize that the heads were the most valuable part of their catch, indicating that this source of revenue is still quite new to some fishermen. Dried Mobula tarapacana gill rakers If a mobula ray is bought by a dried-fish dealer, the gill raker dealers would then purchase the head or the rakers from this person directly at the fish market itself. The head of an average size mobula ray sells for between Rs (US$ 7.30) to around Rs. 1, (US$ 9.12), while the wet cleaned rakers sell for around Rs. 1, (US$ 13.68) per kg to around Rs. 3, (US$ 27.36) per kg, depending on the size.

18 P a g e 18 Disproportionate Value Increase of Manta Rays with Size Size of M. birostris (DW) Average price of whole manta (meat and rakers)* 177 cm Rs (US$ 6.37) 220 cm Rs. 3, (US$ 27.29) 294 cm Rs. 14, (US$ ) 341 cm Rs. 23, (US$ ) 392 cm Rs. 25, (US$ ) 414 cm Rs. 29, (US$ ) > 500 cm More than Rs. 50, (US$ ) * Prices are highly variable, depending on availability of mobula/manta and freshness of meat even though M. birostris is always dried, the older the meat, the less can be made use of. The gill raker dealers that purchase the rakers at the markets will clean and dry them at one of their warehouses or personal houses (see Additional Information at the end of this report for the process of removing and cleaning the rakers from the mobulid rays). Upon drying, the loss of weight means that around 8 kg of wet rakers gives around 1 kg dry rakers. However, the larger the size of rakers and the better the quality, the less is lost. So it is even possible to obtain 1 kg of Manta and mobula gill rakers drying in the sun dry rakers from around 4 kg of wet rakers. The dry rakers are then sold to an Asian exporter at a larger warehouse in the suburbs of Colombo. Information on this exporter is very limited and the gill raker dealers do not seem to know much either. They are usually contacted by an individual who may come and collect the rakers from them, or request them to drop a large shipment of rakers at a sideentrance to one of the warehouses. Gill rakers being removed from a Manta birostris at Mirissa Fish Market The dried gill rakers are sold by the gill raker dealers at prices ranging from Rs. 10, (US$ 90.92) per kg to around Rs. 15, (US$ ) per kg. This may increase to even around Rs. 25, (US$ ) per kg, if the rakers are exceptionally large.

19 P a g e 19 Size of specimens* Gill Raker Pricing Categories Wet rakers (per full mobula/manta head) Selling price (to exporters in Sri Lanka) of dried rakers per kg Small (M. japanica or M. thurstoni) Rs. 1, (US$ 9.10) Rs. 10, (US$ 95.53) Medium (M. tarapacana) Rs. 2, (US$ 18.19) Rs. 12, (US$ ) Large (M. birostris ) Rs. 3, (US$ 27.29) Rs. 15, (US$ ) * Species in brackets are the most common within specified size group. M. birostris have the largest gill rakers vs. body size. Also exceptionally large rakers sell at higher than specified prices. These prices are based on M. birostris individuals not greater than around DW:300 cm. These are prices when gill raker dealers buy the heads from the dried fish dealers. Generally 5-8 kg of wet rakers are required to produce 1 kg of dry rakers (the larger the rakers, the better the wet to dry ratio)

20 P a g e 20 Sri Lanka's Annual Mobulid Ray Catch In order to obtain an estimate for the annual catch of Mobulid rays throughout all of Sri Lanka as a whole, the data collected from the two study markets has been extrapolated to include all the fish markets in Sri Lanka. Estimates of catches at these other fish markets were calculated based on their relative size and popularity. It is also worth noting that even though this research was conducted over a period of only four months, the fish markets were visited by the authors of this report on numerous other occasions during other times of the year, across multiple years, and recorded similar catch numbers at these times to those reported here. So even with the seasonal changes in Sri Lanka (with the two monsoons), it can be assumed that the catch numbers are relatively consistent throughout the year. Furthermore, the fishermen also move to other areas of the ocean (West to East or vice versa) if conditions are too rough, but generally return to the same markets to land their catches. Map of the Fish Markets in Sri Lanka - Made available by the Ceylon Fisheries Harbors Corporation Note: These figures are approximate, providing a conservative estimate of the entire annual catch of mobulid rays in Sri Lanka. It must also be noted that certain traders purchase entire mobulas at other markets around Sri Lanka (particularly in the East and South) and transport to Negombo in order to sell at higher prices, as Negombo is the most popular market in the country. Using the map of fish markets provided by the Ceylon Fisheries Corporation (see above), the largest markets were selected and the following assumptions about their landings were made: Markets with mobulid catch likely to be similar to Negombo's landings: 1. Kalpitiya Markets with mobulid catch likely to be similar to Mirissa's landings: 1. Beruwela 2. Codbay (Trincomalee)

21 P a g e 21 Markets with mobulid catch estimated at 30% of Mirissa's landings: 1. Chilaw 2. Hikkaduwa 3. Galle 4. Hambantota 5. Valachchennai (Reported to land significant numbers of M. birostris) Markets with mobulid catch estimated at 10% of Mirissa's landings: 1. Mutwal 2. Panadura 3. Ambalangoda 4. Dodanduwa 5. Puranawella 6. Kudawella 7. Tangalle 8. Kirinda Estimated Total Annual Landings for Mobulid Ray in Sri Lanka Mobulid Species Total Landings M. birostris 1,055 M. japanica 48,357 M. tarapacana 6,691 M. thurstoni 449 All spp. 56,552

22 P a g e 22 Discussion & Conclusions The data collected in this study indicate the importance of monitoring landings at fish markets around Sri Lanka, since they appear to be responsible for a significant percentage of the global manta and mobula catches. Fishery Impact The extrapolated yearly catches of manta and mobula rays are 1,055 and 55,497 respectively. When certain aspects of manta and mobula rays biology such as their low fecundity rates, slow growth and late maturity are taken into account, these high catch rates suggest significant impacts on the respective populations in this region. These impacts are especially critical for M. birostris, which are estimated to require around 15 years to reach sexual maturity and A pile of Mobula japanica at Negombo fish market in Sri Lanka produce only one pup at a time once every few years at most. M. birostris is already classified as Near Threatened on the IUCN Red List of Threatened Species (assessed in 2006), along with M. japanica and M. thurstoni (which are categorized as Vulnerable for the Southeast Asia region), while M. tarapacana is listed as Data Deficient globally, with a Vulnerable status in the Southeast Asia region due to increasing catches and demand. Virtually no data exists on the natural population sizes of Manta birostris in the Indian Ocean, or indeed throughout their range globally, but given their life history strategies it is highly likely that this fishery is having a significant and detrimental impact on the population. One interesting observation is the comment by the majority of fishermen who claim they still regularly release manta rays from their nets (approximately 50% of which they claim are still alive upon release) because they are too big, not easy to kill, have rough skin, and the meat is not worth very much. A juvenile Mobula japanica, possibly aborted by the mother after she became entangled in the gill net which then ensnared her pup. However, even after taking into account these discarded or released mantas, the fishermen still commented that the numbers of mantas caught overall are significantly lower when compared to the mobula ray catches. The majority of fishermen also commented that the numbers of mantas caught have decreased over the last five years. While this could be due to natural fluctuations in the migration patterns of the species into Sri Lankan waters and the surrounding seas, this drop in catch

23 P a g e 23 rates is more likely to be due to the increased fishing pressures being exerted upon this species throughout their range. Nursery Ground Another vital discovery at the markets was that the overwhelming majority of the M. birostris recorded were juveniles and sub-adults (n=38/40), indicating the high possibility of the existence of a manta 'nursery' grounds close to shore in the South of Sri Lanka, where the majority of the mantas in this study were captured. Observations of juvenile M. birostris in the wild are extremely rare, so to find an area where juveniles are consistently encountered could prove to be extremely important for this species, of which we still know so little. Further research into this preliminary data is of paramount importance, but if this area of southern Sri Lanka is indeed an important aggregation site for juvenile M. birostris it would be the first one of its kind to be reported anywhere in the world and would make a strong argument for the rapid introduction of conservation measures to protect these species and this aggregation area within Sri Lanka. A juvenile male Manta birostris is chopped up into five separate pieces in order to fit into the fishing boat's hold before being pieced back together again for sale on the docks at the fish market Gill Raker Trade The demand for gill rakers, which is driving the fishing of mobulid rays, appears to be increasing. Most of the dealers currently involved in this trade are new to this particular business and say that in the last four or five years there has been a rapid increase in demand and price for these gill rakers. This new demand could well be linked to the increasing prosperity of the mainland Chinese who are the primary consumers of rakers, and/or the collapse of mobulid fisheries in other countries. While there are still occasional cases of fishermen throwing away the heads of manta or mobula out at sea, most are now aware that this new demand for the mobulid's rakers makes fishing the animals worthwhile. The fishermen however, do not benefit as much as the middlemen from the mobulid fishery, but do rely on these species- when catches of other more desirable fish stocks are scarce. Mobulid rays are currently still mainly caught only as bycatch and are often avoided altogether by the fishermen if possible due to their propensity to destroy or entangle fishing nets, and because the meat is harder to keep fresh for long periods at sea. This means that the fishermen usually tend to keep mobulid rays in their ice hold only when on the way back to shore. However, before the A mound of mobulas are offloaded onto the docks at Mirissa Fish Market in Sri Lanka

24 P a g e 24 increased demand for the rakers, the boats rarely targeted mantas or mobulas, even when returning to shore. If catches of the more desirable species continue to decline the fishermen will be driven more often to fill their holds with the less desirable mobulids. The main benefactors of the gill raker trade in Sri Lanka are the few local gill raker dealers and the exporter/s. Overall this is a much smaller number of people than would be involved in the trade of other fish stocks, such as tuna. While mobula meat is consumed locally, this consumption is still limited due to its inferior quality when compared to most other locally available fish species, making it much less desirable. For example, while fresh mobula meat would sell for only around Rs (US$ 2.18) per kg, skipjack tuna sells at over Rs (US$ 3.18) per kg, swordfish at around Rs (US$ 3.36) per kg and marlin at approximately Rs (US$ 4.91) per kg. Additionally, most manta and mobula meat, which is not fresh, is sold to the dry fish market at less than Rs (US$ 1.09) per kg and these prices can drop to around Rs (US$ 0.64) per kg when large numbers of mobula are landed, flooding the market. However, even the smallest dried gill rakers sell for over Rs. 10, (US$ 95.53) per kg, making them considerably more valuable than the meat. Conclusions If the fishing of manta and mobula rays carries on at its existing levels in Sri Lanka it is highly likely that there will be a population crash of these species in this region within just a few years. Similar population crashes have been documented in the gulf of Mexico and Indonesia where boom and bust fisheries for these species have occurred in recent decades. It is therefore critical that steps are urgently taken to stop these unsustainable fisheries and prevent a repeat incident, if it is not already too late. One of the easiest and most effective ways of Three juvenile Manta birostris cut up for sale at Mirissa Fish Market in Sri Lanka addressing this problem would be to introduce a ban on the export of gill rakers from Sri Lanka, which is the primary driving force behind the manta and mobula fishery. Such a ban, coupled with the lack of demand for the animal s meat and the difficulties in fishing these species, would immediately make the fishery for these species economically unviable for the Sri Lankan fishermen. Furthermore, such a ban would have very little overall monetary loss for the local economy as the majority of the profits from this fishery are going to just a few gill raker dealers. Additionally, more significant profits are made overseas by the importers and retail stores in Asia and not by Sri Lankans. In many other country's with populations of manta rays these animals often become a major tourist attraction, generating millions of dollars annually for the local economy through directed tourism excursions. In the Maldives, for example, manta ray tourism has been calculated to be worth 8.1 million US$ annually to the local economy in direct revenue from manta tourism dive and snorkel excursions (Anderson et al, 2010). This alternative source of revenue is completely sustainable if managed effectively. With Sri Lanka's tourism industry continuing to make a resurgence as peace and stability returns to this magnificent island after years of civil war, it would seem that this is the

25 P a g e 25 perfect time to promote manta ray tourism in those areas where encounters are most reliable. Indeed it appears that the best manta aggregation sites so far identified are in the same area that blue whales are also spotted with regularity at certain times of the year. Manta and whale watching trips could be promoted together, and the key aggregations area should be set aside as a Marine Protected Area (MPA) with a comprehensive management plan implemented to protect and benefit not just the marine life and habitat, but the local communities as well. Future Work For future projects, expansion of monitoring to other fish markets should be taken into consideration along with more regular monitoring (daily basis). This would of course require continuous funding, along with additional volunteers and project leaders for each fish market. However, certain fish markets (such as Mirissa) may perceive constant monitoring as a direct threat, so this would need to be undertaken with caution. Most fishermen at the fish markets have experienced the implementation of species specific fishing bans before after the conduction of long-term research at markets (e.g. the ban on dolphin fishing). A long-term conservation strategy is also needed, providing scientific data and recommendations to the Fisheries and Wildlife departments of Sri Lanka. This should also include an action plan for raising awareness and improving education regarding over-fishing within the local communities, presenting suitable alternatives to fishing wherever possible and stressing the virtues of sustainable fishing techniques. Methods to efficiently monitor and enforce the conservation processes and any implemented regulations should also be taken into consideration. While continued and expanded work is needed on this fishery in Sri Lanka, there is also an urgent need to assess the extent and impact of a similar fishery which are occurring in India. To date no data has been collected on the mobula and manta ray fishery in this much larger neighboring country, where the scale of the fishery is likely to be even larger than in Sri Lanka.

26 P a g e 26 Additional Information What is a Gill Raker? Every manta or mobula has five pairs of gills, each protected inside a gill slit. Inside each of the ten gill slits there is one complete feathery gill raker which forms a circle around the periphery of the slit, trapping their planktonic food as it is funneled through the mobula or manta ray's mouth and out through these gill rakers. The complete brachial set of gill rakers from inside the mouth of a small Mobula japanica Depending on the method by which the feathery gill rakers are removed from the cartilaginous structure of the animals head, the rakers are usually broken down into halves, or quarters in extremely large individuals. As a result, in the gill raker trade a "raker" is in fact usually one half of a full raker, resulting in 20 rakers per individual ray. The waste remains from the gill raker removal process (heads, cartilage and filaments) are also cut up and dried. These get sold among the lowest quality of dry fish, usually used as animal fodder. Five pairs of gill slits on the underside of a Manta birostris The Process of Removing and Cleaning the Gill Rakers A. The gill rakers are cut from head. B. Excess meat is removed.

27 P a g e 27 C. The rakers are cut from the supporting cartilage. D. Each individual raker is separated. E. The individual rakers are then cut in half. F. Excess meat from each raker is removed. G. The waste remains are sold as dried fish. H. The final " raker" which is then dried.

28 P a g e 28 Acknowledgements & Thanks The Manta Trust would like to thank all those people who contributed their knowledge, time and images to the creation of this guide. Without their help and assistance this guide would not have been possible. I would like to say a special thanks to the Save Our Seas Foundation for supporting our research, enabling us to focus our time and effort on this report's completion. I would also like to thank the Manta Ray of Hope Project for supporting our fieldwork and for supplying market research data at other study sites in Asia. All images are copyright to: Daniel Fernando, Guy Stevens, Gisela Kaufmann & Thomas Peschak.

29 P a g e 29 References Anderson, R.C., Adam, M.S., Kitchen-Wheeler, A-M. and Stevens, G., (2010). Extent and economic value of manta ray watching in Maldives. Tourism in Marine Environments. Dewar, H., (2002). Preliminary report: manta ray harvest in Lamakera. Report to the World Wildlife Fund. Cited on 12 th August, Available online at: IUCN Red List of Threatened Species, (assessed in 2006). Manta birostris; Mobula Japanica; Mobula tarapacana; Mobula thurstoni. Cited on 15 th August, Available online at: < Mahinda Chintana, (2005). The 2005 Election Campaign by the President of Sri Lanka. Cited on 20 th August, Available online at: < Sri Lankan Department of Fisheries and Aquaculture Resources, (2007). Fisheries Data. Cited on 20 th August, Available online at: < Stevens, J.D., Bonfil, R., Dulvy, N.K. and Walker, P.A., (2000). The effects of fishing on sharks, rays, and chimaeras (chondrichthyans), and the implications for marine ecosystems. ICES Journal of Marine Science, 57: White, W., Giles, J., Dharmadi and Potter, I. C., (2006). Data on the bycatch fishery and reproductive biology of mobulid rays (Myliobatiformes) in Indonesia. Fisheries Research, 82(1-3):